The fine structure of the book lungs of scorpions is diverse and phylogenetically informative, but has not been comprehensively investigated across the major lineages of the order. In this contribution, we present a fully illustrated atlas of the variation in book lung fine structure among 200 exemplars from 100 genera and 18 families of extant scorpions. We document variation in the surface sculpturing of the respiratory lamellae, the edges of the lamellae in the atrial chamber, and the posterior valvelike edges of the spiracles. These data provide insights into the phylogenetic relationships among Recent scorpions at several branches of the tree.
According to Weygoldt and Paulus (1979b), Arachnida Lamarck, 1801, represent the monophyletic terrestrial lineage of Metastomata 43Weygoldt and Paulus, 1979, which includes the extinct aquatic Eurypterida Burmeister, 1894. With few exceptions (e.g., some Acari Sundevall, 1833 and Araneae Clerck, 1757), all arachnid species occupy terrestrial habitats today. There are several challenges associated with a terrestrial lifestyle, arguably the most severe being the evaporative water loss that results from breathing air. Different solutions for breathing air, in the form of internalized respiratory organs, have evolved among different terrestrial animals. Examples include the lungs of vertebrates, the tracheae of insects, and the gills, modified for air breathing, of terrestrial crustaceans.
The respiratory organs of scorpions, Scorpiones C.L. Koch, 1837, and tetrapulmonate arachnids, Megoperculata Börner, 1902, are called book lungs due to the booklike appearance of the layered, sheetlike lamellae (fig. 1). Book lungs are the primary organs for respiration in arachnids, presumed to have evolved as a consequence of terrestrialization in the stem group of Arachnida (Scholtz and Kamenz, 2006). Book lungs are homologous with, and/or functionally substituted by tracheae in entelegyne spiders and apulmonate arachnids, Apulmonata Firstman, 1973 (Hilken, 1998; Weygoldt and Paulus, 1979a).
Euscorpius carpathicus candota Birula, 10-3: 1 ♀ (HUB): diagrammatic representation of longitudinal histological section through book lung (foreground), showing cuticular structures in three dimensions.
The book lungs of Recent scorpions are homologous (Scholtz and Kamenz, 2006). Their similar structural complexity and identical positions within the fourth to seventh opisthosomal segments (fig. 2) are indicative of common ancestry. Several substructures, present in all scorpions examined thus far, are hypothesized to have been present in the common ancestor of arachnids (Scholtz and Kamenz, 2006). For example, bridging trabeculae (cuticular rods) connecting the proximal surfaces of adjacent lamellae and cellular pillars inside the lamellae (fig. 13) occur in all scorpions that have been studied, and also in tetrapulmonates (Scholtz and Kamenz, 2006). Other characters, e.g., spinelike processes on the lamellar edges, are widespread among scorpions and tetrapulmonates. These characters are synapomorphic for Arachnida, but have undergone secondary modifications in Scorpiones and all remaining terrestrial arachnids, called Lipoctena Pocock, 1893 (Scholtz and Kamenz, 2006).
The most obvious feature of the book lungs—their lamellate design (fig. 1)—recalls the book gills of aquatic ancestors. Gills are probably synapomorphic for Euchelicerata 43Weygoldt and Paulus, 1979. Similar structures are retained in the four species of extant horseshoe crabs, Xiphosura Latreille, 1802. Book lungs are therefore hypothesized to be homologous to the book gills of xiphosurans (Lankester, 1881a, 1881b; Kingsley, 1885) and probably became internalized during the terrestrialization of Arachnida (Weygoldt and Paulus, 1979a).
The importance of book lung morphology for the phylogeny and classification of scorpions was first recognized by Laurie (1896) and Pavlovsky (1926). Pavlovsky (1926) presented a survey of book lung morphology in 35 species from 31 genera and 11 families of scorpions (table 1), based on light microscopy. Except for mention of the shape of the spiracles in various taxonomic and phylogenetic works, no comparative studies of book lung morphology were subsequently conducted until Kamenz et al. (2005). Using scanning electron microscopy (SEM), Kamenz et al. (2005) confirmed Pavlovsky's (1926) discoveries in an examination of the fine structure of book lungs in 29 species from 28 genera and 10 families of scorpions. Due to limitations on the availability of material and constraints on the number of illustrations that could be published, the study by Kamenz et al. (2005) provided only an overview of variation in the book lung fine structure of scorpions; major lineages were not documented, restricting the utility of the data presented for phylogenetic interpretation. The aim of the study presented here is to expand the work of Kamenz et al. (2005) by providing a more comprehensive, fully illustrated survey of book lung fine structure across all the major lineages of scorpions. Exemplar species representing all scorpion families and as many genera as possible were studied and illustrated in the course of this study, providing a standardized framework that can be used to describe and define characters for phylogenetic analyses at multiple branches of the scorpion tree.
We present one interpretation of the variation observed by describing three characters, defined by Kamenz et al. (2005), which appear to be phylogenetically informative among the taxa studied (table 2): the surface sculpturing of the respiratory lamellae, the edges of the lamellae in the atrial chamber, and processes on the posterior valvelike edge of the spiracles. We chose these three characters because they are readily apparent with the SEM, and appear to be consistent within species as determined by the examination of multiple specimens. Further genetic, cellular, developmental and ultrastructural studies of the book lungs remain to be undertaken. The standardized illustrations provided in this atlas are intended to serve as a reference for further interpretation and provide a foundation upon which future studies of the book lungs of scorpions, and other arachnids, can be built.
States of the book lung characters observed in exemplar species of Scorpiones Lamellar surface (Lam. surf.): simple trabeculae (1); branched trabeculae (2); slender venation (3); ribbed venation (4). Lamellar edge (Lam. edge): bristles (1); spines (2); thorns (3); smooth/wrinkled (4); meandering (5); arcuate bows (6); padded (7). Posterior spiracle edge (Spir. edge): hillocks (1); subconical (2); hairlike (3); flattened (4); scaly (5); chisel-like (6); hexagonal tiles (7); treelike (8); subtree-like (9); polygonal columns (10); clublike (11); spiked macelike (12)
Materials and Methods
The study presented here applies the “exemplar approach” (Yeates, 1995; Prendini, 2001), according to which an exemplar species represents a supraspecific taxon (usually, but not exclusively, in the context of a phylogenetic analysis). The advantages of this method are obvious: (1) it is impossible to gather data from all species, but the use of exemplars enables the variation to be systematically surveyed in a subsample; (2) exemplar species make no assumptions about the monophyly of the supraspecific taxa they represent, allowing monophyly to be rigorously tested during a phylogenetic analysis; (3) multiple sources of data (anatomy, morphology, behavior, DNA, etc.) are readily combined if gathered from the same exemplar species; (4) the use of exemplars restricts data matrices to manageable sizes for computational purposes.
The exemplar approach is more powerful (i.e., it provides a more rigorous test of the hypothesis of monophyly) when more exemplar species are studied per higher taxon, and when these species are selected to represent the maximum morphological diversity within each higher taxon (Prendini, 2001). In the present study, 200 exemplars in 100 genera were selected to represent all 18 scorpion families (table 2; appendix 1) listed in the status quo classification scheme presented by Prendini and Wheeler (2005). Type species of genera were selected preferentially, when available. Multiple species were sampled from diverse and speciose genera, e.g., Tityus C. L. Koch, 1836, to assess the extent of variation among congeners. Contingent on the availability of suitable material, congeneric exemplars were selected to maximize morphological diversity (Prendini, 2001). In this atlas of book lung fine structure, data gathered from the exemplar species selected are presented and discussed by family for operational purposes, with putative phylogenetically related families (e.g., buthoids, chactoids, and scorpionoids) discussed in sequence, rather than in alphabetical order. Within each family, the figures for the species are presented in alphabetical order by genus. This study makes no assumptions about the monophyly or content of these families, however. It serves primarily to document the variation in book lung fine structure and stimulate further investigation into the subject.
Material, Preparation, and Terminology
Material examined was borrowed from or studied in situ at the following collections: American Museum of Natural History, New York (AMNH); Museum National d'Histoire Naturelle, Paris (MNHN); Museum für Naturkunde, Berlin (MfN), bearing ZMB accession numbers. Available collection data for voucher specimens studied are provided in appendix 1. Mounted SEM stubs are also deposited in these collections.
Standard SEM techniques were used for the preparation and investigation of book lungs. Book lungs were dissected from scorpions preserved in 70–100% ethanol. Several specimens were fixed in Bouin's fluid (15 ml saturated picric acid, 5 ml 35% formaldehyde, and 1 ml acetic acid) or using a method adapted by Karnovsky (1965), in a solution of 0.1 M phosphate-buffered saline (PBS: 10.9 g Na2HPO4 [anhydrous], 3.2 g NaH2HPO4 [anhydrous], and 90 g NaCl in 1000 ml distilled water, pH 7.2), 3.7% formaldehyde, and 2.5% glutaraldehyde plus postfixation in 2% osmiumtetroxide. Bouin's fluid was washed out with 70% ethanol and Karnovsky's fixatives using PBS first and 40% ethanol in subsequent steps. The ethanol concentration was sequentially increased to 100% for dehydrating the tissues. The ethanol was then removed in critical point dryers, BAL-TEC CPD 030 at the Humboldt-Universität, Berlin (HUB), Emitech K850 (MNHN), or in an oven (AMNH) at 60°C.
After dehydration and prior to examination with the SEM, the lungs were dissected to expose the interior structures before mounting on common stubs. The prepared lungs were then sputter-coated with gold template in a BAL-TEC SCD 005 (HUB), or with gold-paladium in a Polaron SC 7640 (MfN), Joel JFC-1200 Fine Coater (MNHN), or DENTON Desk II (AMNH). The following SEMs were used in the course of the study: a Leo 1540 VP (MfN), a Joel JSM-840 A (MNHN), and a Hitachi S 4700 (AMNH). Images of the book lungs prepared for each species studied were assembled into plates using Adobe Photoshop and Illustrator. Terminology for book lung structures follows Kamenz et al. (2005), a detailed explanation of which follows in the section on Fine Structure of Scorpion Book Lungs.
Gross Morphology and Function of Scorpion Book Lungs
Position of book lungs
The respiratory organs of scorpions occur on the inner surface of the ventral exoskeleton in the mesosoma (fig. 2). A pair of book lungs is situated laterally on the sternites of the third to sixth visible opisthosomal segments (identical to the fourth to seventh embryological opisthosomal segments; Brauer, 1895; Simonnet et al., 2006), following the pectinal segment. A mostly slitlike, in some cases oval or almost circular spiracle (fig. 3) demarcates the posteromedial margin of the book lung. The spiracle is the respiratory opening leading into the atrium of the book lung. The distance from the spiracle to the anterior margin of the sternite is approximately equal to three times the distance between the posterior margin and the spiracle. The longitudinal axis of the spiracle is inclined toward the transverse axis with the medial end lying anteriad.
Each book lung consists of a stack of leaflike lamellae situated above the ventral sternite (Treviranus, 1812; figs. 1, 4). We define the lamellae as a double layer of cuticle that is flooded by hemolymph and surrounded by air. The adjacent layers of cuticle surrounding the air between the lamellae are saclike in all terrestrial arachnids and are therefore called air sacs (fig. 5). The air sacs are held in place by bandlike ligaments (fig. 6) from an overlying layer of connective tissue in the hemolymph space, called the fenestrated membrane (Farley, 1990; fig. 7). The fenestrated membrane covers the lung from above and is held to the pericard of the heart by the hypocardial ligament (figs. 7, 8).
The lamellae are not in direct contact with the inner cuticular surface of the sternites, but are separated from it by a flat layer of the epidermis and a narrow hemolymph space (fig. 1). The stack of lamellae is slanted dorsoventrally with the medial side of the book lung situated closest to the inner surface of the sternite and the uppermost lamella situated on the lateral margin of the sternite (fig. 9). The proximal surfaces of the parallel lamellae are shallowly inclined, each lamella sloping slightly from dorsomedial to ventrolateral, to almost horizontal. The distal edges of the lamellae are more steeply inclined in the same direction. There are fewer lamellae, aligned almost horizontally, in smaller species. The lamellae are more numerous and inclined, to almost vertically aligned, in larger species.
Each air sac (fig. 5) has the shape of an almost straight or bent oval that is distally truncated. The straight distal edge of one lamella merges with the distal edge of the adjacent lamella to form the entrance of an air sac (fig. 1). All the distal lamellar edges together form a grill, merging continuously into the wall of the atrium. The atrial chamber (figs. 1, 4) is lined by cuticle, which is strongly folded and covered with small wartlike cuticular processes (fig. 10). An area of almost unfolded and smooth, wart-free cuticle occurs laterally at the regions of transition (with respect to the axis of the spiracle) where the atrium joins the posterior edge of the spiracle (figs. 1, 11). Cuticular processes, shaped like shallow bars or flat lobes (fig. 11), occur on the central region of transition from the atrial wall to the posterior spiracle edge. The shape of these processes changes closer to the posterior spiracle edge, where they transform into the taxon-specific structures described in more detail below.
Each lamella comprises two very thin, parallel layers of epidermal cells on both outer surfaces (Scholtz and Kamenz, 2006). Each layer of epidermal cells is supported by a thin layer of cuticle that separates the inner hemolymph space of the lamellae from the outer air space (figs. 1, 12). The hemolymph space, inside the lamella, is maintained at a uniform width by cellular pillars (figs. 1, 13). These cellular pillars are situated at regular intervals across the inner surfaces of the lamellae, providing a constant space for hemolymph between the inner surfaces of the two adjacent cuticle layers within each lamella. Each pillar comprises two or more cells, which originate on adjacent surfaces and meet each other in the middle, and is filled almost entirely by the nuclei of the pillar cells (Scholtz and Kamenz, 2006).
The cuticular surface of the lamellae is covered with cuticular structures that prevent the air space from collapsing. The proximal one-third to one-fifth of the lamellar surface is covered, in all scorpions, with bridging trabeculae (described further below). The distal two-thirds to four-fifths of the lamellar surface are covered with one of two kinds of cuticular structures that are not connected to the adjacent lamellae (Laurie, 1896): reticulate venation or papillate trabeculae. Venation, observed in buthoid scorpions, covers both sides of the lamellae (fig. 15C, D). Papillate trabeculae (fig. 15A, B), observed in nonbuthid scorpions, occur only on the ventral surfaces of the lamellae; their free ends are directed toward the adjacent lamellar surfaces.
Trabeculae are cuticular processes (figs. 12, 15) that separate adjacent lamellae from one another and prevent collapse of the air space with consequent reduction in the respiratory surface. Bridging trabeculae (fig. 12) are unique in forming continuous columns between adjacent lamellae. Due to their equal size and perpendicular arrangement at regular intervals, bridging trabeculae hold the lamellae at a very constant distance apart, resulting in the parallel appearance of the proximal surfaces of the lamellae.
Bridging trabeculae are present in the book lungs of all arachnids (Scholtz and Kamenz, 2006) and occur on the proximal surfaces of the book lung lamellae of all scorpions (figs. 1, 12), regardless of the presence of venation or trabeculae on the distal surfaces of the lamellae. Bridging trabeculae are situated in a bandlike zone along the anterior to medial margin of each lamella (fig. 5).
Air flows through the spiracle into the atrium (figs. 1, 4) of the book lung and from there into the air sacs between the lamellae, where it is separated from the hemolymph only by a single layer of epidermis and cuticle. Gas exchange, by diffusion to and from the hemolymph inside the lamellae, occurs across this extremely thin lamellar surface. Hemolymph flows through the lamellae from the ventral hemolymph sinus to the lateral pneumocardial sinus (fig. 8) receiving oxygen and releasing carbon dioxide along the way. The oxygenated hemolymph is transported dorsally to the heart and then distributed throughout the body.
Spiracles and ventilation
Each spiracle (fig. 3) is a small circular, oval or slitlike opening to the book lung in the sternite. The spiracle regulates the influx of gases and can be closed to prevent loss or penetration of gases, liquids, and solid particles. Cuticular processes on the spiracle and the distal edges of the lamellae probably reduce the penetration of dust particles.
Opening of the spiracle is regulated by sensory cells detecting the concentration of carbon dioxide and the pH of the hemolymph (Farley, 1990). The poststigmaticus muscle (fig. 1), attached to the posterior edge of the spiracle (Fraenkel, 1930; Pavlovsky, 1926; Du Buisson, 1925; Vyas and Laliwala, 1972, 1976; Farley, 1990), connects to the posterior part of the sternite or the posterior intersegmental membrane (fig. 14). The spiracle is opened on contraction of this muscle, which causes the posterior edge to roll or flap back, away from the anterior edge. This mechanism serves to regulate the partial pressure of oxygen and carbon dioxide (Fincke and Paul, 1989). Closure of the spiracle is a passive process. The posterior edge of the spiracle is flexible and closes the spiracle on relaxation.
Whether gas exchange in scorpions occurs by diffusion or active ventilation has not been conclusively demonstrated. Fraenkel (1930) described pumping movements of the book lung due to pulsation of the heart, transmitted via pneumocardial bands, the hypocardial ligaments described by Farley (1990), and ventilation by muscles attached to the posterior spiracle edge and the atrium. However, Fincke and Paul (1989) contradicted the suggestion of effective ventilation. Their physiological investigations on the mygalomorph spider, Eurypelma californicum Ausserer, 1871, the entelegyne spider, Cupiennius salei (Keyserling, 1877), and the scorpion, Pandinus imperator (C.L. Koch, 1841) did not reveal any rapid, rhythmic movements of the spiracle in dormancy or during phases of high activity as occur, for example, in vertebrates. Rhythmic stirring of the hemolymph stream through the book lung, generated by pulsation of the heart, might support gas exchange (Farley, 1990), but this remains to be demonstrated.
Fine Structure of Scorpion Book Lungs
The distal lamellar surfaces of scorpions may be covered with two distinct kinds of structures (character 1; fig. 15): reticulate venation or cylindrical, rodlike (papillate) trabeculae. Distal, in the sense used here, refers to the main part of the lamellar surface, distinguishing it from the surfaces along the proximal edges of the air sacs (fig. 5), where adjacent lamellae are connected by bridging trabeculae. There are two distinct states for both structures (reticulate venation and papillate trabeculae), resulting in four states for the character: simple trabeculae (state 1); branched trabeculae (state 2); slender venation (state 3); ribbed venation (state 4).
The two types of papillate trabeculae were previously described by Kamenz et al. (2005). Simple trabeculae (state 1) are observed in most nonbuthid scorpions. These trabeculae are blunt or knoblike apically. Branched trabeculae (state 2) are slender columns with as many as five narrower branches apically.
Slender venation (state 3), first described by Kamenz et al. (2005), consists of branching, reticulate veins that enclose slender areas directed toward the lamellar edges. Ribbed venation (state 4), identified here for the first time, is characterized by veins surrounding polygonal surfaces, which are broader than the surfaces characteristic of state 3 but become consistently more slender near the distal lamellar edges. Each polygonal surface contains up to five parallel ribs, directed toward the distal lamellar edge. Ribbed venation is a new state, not previously mentioned by Kamenz et al. (2005).
Distal edges of lamellae
Structures on the lamellar edges (character 2) differ significantly from those on the lamellar surfaces and are restricted to the immediate edge of the lamella (fig. 16). Although a gradation is sometimes observed from structures on the lamellar surfaces to those on the lamellar edges, the change is usually rather abrupt. Seven different states of structures on the lamellar edge can be distinguished, six of which have already been described by Kamenz et al. (2005): bristles (state 1); spines (state 2); thorns (state 3); smooth/wrinkled (state 4); meandering (state 5); arcuate bows (state 6); padded (state 7). Padded structures are described here for the first time.
The first three states of lamellar edge structures are similar. Bristlelike (state 1) and spinelike (state 2) structures have narrow bases, are rather thin, and taper slightly at the ends. Both structures occur on lamellae covered with trabeculae, but are readily distinguished from the latter, which are shorter and more cylindrical in shape. Whereas bristles are soft and flexible, spines are rigid and straight. Bristles point in all directions and often occur side by side around the semicircular (cross section) lamellar edge. Spines are usually arranged almost parallel to one another, projecting away in the same plane as the lamella. The third state of similar structures, thorns (state 3), are rather short and usually exhibit a broad base. Thorns usually arise from wrinkled venation and occur more sporadically along the lamellar edges than spines.
Venation often merges with a smooth or sometimes wrinkled (state 4) lamellar edge. Wrinkles may be very deep but are clearly distinct from meandering structures (state 5), which occur together with trabeculae on the lamellar surfaces. Meandering structures consist of more or less slender areas winding along the lamellar edges, surrounded by winding, raised bulges, sometimes enclosing groups of small spines.
The remaining states of lamellar edges are quite different from one other and from all others. Arcuate bows (state 6), the ends of which merge with the lamellar edge to create a complex, irregular reticulate vault, are always observed together with trabeculae on the lamellar surfaces. Flat or pillowlike pads (state 7), observed only in Chaerilus Simon, 1877, cover the lamellar edges with a deeply perforated network.
Posterior edge of spiracle
The posterior spiracle edge (character 3) exhibits the greatest diversity of structures (fig. 17). Twelve character states, five of which (states 8–12) are described here for the first time, can be clearly defined: hillocks (state 1); subconical (state 2); hairlike (state 3); flattened (state 4); scaly (state 5); chisel-like (state 6); hexagonal tiles (state 7); treelike (state 8); subtree-like (state 9); polygonal columns (state 10); clublike (state 11); spiked macelike (state 12). The first three character states are simple processes, the others more complex structures containing distinct substructures.
Kamenz et al. (2005) described simple cuticular processes on the posterior edge of the spiracle, ranging from small, shallow hillocks (state 1), through subconical processes that are higher than wide (state 2), to very long, hairlike processes (state 3). Kamenz et al. (2005) described lobelike, flattened processes, the tips of which vary from a single blunt end to several pointed tips, as state 4. The flattened structures described by Kamenz et al. (2005) are sometimes broadened, and overlap one another to a lesser extent than scales (state 5). Chisel-like structures (state 6) are characterised by a nearly cylindrical shaft with a flattened tip, bearing a few distinct teeth. The flattened, scaly and distinct chisel-like structures appear to be points on a continuum of variation.
The hexagonal pillars (state 7), described by Kamenz et al. (2005), are here renamed hexagonal tiles to avoid confusion with the pillar cells inside the lamellae (Scholtz and Kamenz, 2006). This amended term refers to the regular arrangement of each hexagonal plate in a particular surface, and the very regular, jointlike gaps between them. The height of these structures varies from almost zero, when only the hexagonal plates are visible, to about five times the diameter of the plate. The more slender shaft is usually cylindrical to hexagonal.
Treelike structures (state 8), i.e., spinelike to hairlike cuticular processes with several branches, are observed on the posterior spiracle edge of the bothriurid scorpion, Urophonius iheringii. Structures on the posterior spiracle edge of the bothriurids, Centromachetes obscurus and Timogenes mapuche, exhibit similar outgrowths, but the branches on these structures are short and thornlike. These subtree-like structures (state 9) may be an intermediate step in the transformation between subconical and treelike structures.
The structures on the posterior spiracle edge of Paruroctonus Werner, 1934 are superficially similar to hexagonal tiles (state 7). However, the apical plates of these structures are smaller, almost as wide as the shaft, irregular in shape, and do not all lie in the same plane. The gaps between the plates are much larger and less regular than in state 7. These structures, not considered to be homologous with the hexagonal tiles, are termed polygonal columns (state 10).
A unique, distally expanded clublike structure (state 11) is observed on the posterior spiracle edge of Teuthraustes Simon, 1878. Another unique structure, a spiked mace, shaped somewhat like a flattened hillock, densely covered with subconical thorns (state 12), is observed on the posterior spiracle edge of Uroctonites huachuca.
Book Lungs of Pseudochactidae
Viewed from the air space, the ventral surfaces of the book lung lamellae of P. ovchinnikovi are covered with simple, conical trabeculae with a broad base (pl. 1A). The trabeculae are supported by foldlike ridges merging into the lamellar surface.
Distal edges of lamellae
Bristlelike or spinelike processes project into the atrium from the lamellar edges of P. ovchinnikovi (pl. 1B). Sail-like cuticular folds are stretched between the lamellar edge and the bases of these spines.
Posterior edge of spiracle
Extremely flattened subconical structures occur along the posterior edges of the spiracles of P. ovchinnikovi (pl. 1C). Distal teeth are sometimes also observed.
Book Lungs of Buthidae and Microcharmidae
Viewed from the air space, the distal lamellar surfaces of all buthoid exemplars (including Microcharmus Lourenço, 1995) studied during the present investigation are covered on both sides with reticulate venation (pls. 2–59A). The veins are ridges that branch and fuse, surrounding more or less slender, polygonal surfaces. In some New World buthid exemplars examined (C. elii, M. rickyi, Tityus, and Z. fuscus; pls. 12A, 33A, 46–55A, 58A), the surfaces between the veins are usually polygonal and contain up to five parallel striations (ribs), but become more slender toward the distal edges of the lamellae. In all other buthoids, including Microcharmus, they are more slender (pls. 2–11A, 23–32A, 34–45A, 56A, 57A, 59A), and often contain folded ridges that branch perpendicularly or wind irregularly from the veins.
Distal edges of lamellae
The distal edges of the lamellae of buthoids (including Microcharmus) are smooth to wrinkled, with larger veins winding along the edges. Smooth edges are observed in C. elii (pl. 12B), Centruroides Marx, 1890 (pls. 13–17B), G. hirtus (pl. 21B), R. rochae (pl. 44B), and Tityus (pls. 46–55B). More wrinkled edges, with sporadic thorns, occur in A. cussinii (pl. 2B), B. buettneri (pl. 7B), H. conspersus (pl. 22B), I. angusticaudis (pl. 24B), Lychas C. L. Koch, 1845 (pls. 30B, 31B), M. rickyi (pl. 33B), O. dentatus (pl. 35B), R. bonettii (pl. 40B), R. junceus (pl. 41B), R. laticauda (pl. 42B), R. princeps (pl. 43B), T. baroni (pl. 45B), and Z. fuscus (pl. 58B). All other buthid exemplars exhibit short, strong thorns projecting at regular distances along the lamellar edges.
Posterior edge of spiracle
Low hillocks or subconical spinelike structures are observed along the posterior edges of all buthoid exemplars (pls. 2–58C). These structures are rounded in C. exilicauda (pl. 13C), C. maindroni (pl. 20C), K. methueni (pl. 27C), M. eupeus (pl. 32C), C. elii (pl. 12C), and form hillocks in G. hirtus (pl. 21C), H. conspersus (pl. 22C), I. angusticaudis (pl. 24C), Isometrus Ehrenberg, 1828 (pls. 25C, 26C), L. kessleri (pl. 29C), Lychas (pls. 30C, 31C), Orthochirus Karsch, 1891 (pls. 36C, 37C), P. pegleri (pl. 39C), R. bonettii (pl. 40C), R. laticauda (pl. 42C), T. baroni (pl. 45C), U. flavoviridis (pl. 56C), and V. globimanus (pl. 57C). The processes on the posterior edges of the spiracles are spinelike and pointed in all other buthoid exemplars. Data for the spiracle edge are unavailable for A. cussinii, T. bolivianus, and Microcharmus.
Book Lungs of Chaerilidae
The surface structure of the lamellae of C. truncatus (pl. 60A) is similar to that observed in the New World buthid exemplars of Tityus, Caribetityus Lourenço, 1999, Microtityus Kjellesvig-Waering, 1966, and Zabius Thorell, 1893. It is characterized by reticulate venation surrounding slender to polygonal surfaces with internal striations (ribs) running parallel toward the distal edge of the lamella.
Distal edges of lamellae
Irregularly arranged, pillowlike pads, mostly covered with a perforated network of veins, demarcate the distal edges of the lamellae of C. truncatus (pl. 60B). The pillowlike sculpturing along the lamellar edges gradually transforms into an extremely dense reticulate network of veins on the lamellar surfaces.
Posterior edge of spiracle
Subconical or spinelike processes are observed on the posterior edges of the spiracles of C. truncatus (pl. 60C).
Book Lungs of Iuridae
Distal edges of lamellae
The distal lamellar edge exhibits diverse structures in Iuridae (pls. 61–66B). Whereas A. phaiodactylus (pl. 61B) and H. charcasus (pl. 64B) possess flexible bristles, rigid spines are observed on the lamellar edges of H. hirsutus (pl. 65B). The lamellar edges of C. keyserlingi (pl. 63B) are covered with arcuate bowlike structures. In the iurine exemplars, C. nordmanni (pl. 62B) and I. dufoureius (pl. 66B), meandering bulges wind along the lamellar edges and surround slender areas sometimes enclosing small spines.
Posterior edge of spiracle
The structures on the posterior edge of the spiracle are similarly diverse in Iuridae (pls. 61–66C). Hadruroides charcasus (pl. 64C) displays low hillocks and subconical processes, H. hirsutus spinelike processes (pl. 65C), and C. keyserlingi (pl. 63C) spinelike processes with a tendency to branch (subtree-like). The processes along the spiracle edge of C. nordmanni (pl. 62C) are broad hillocks or lobes with teeth arranged in irregular rows along the distal margin.
Book Lungs of Euscorpiidae and Scorpiopidae
The ventral surfaces of the lamellae of all euscorpiid and scorpiopid exemplars studied are covered with regularly spaced, simple trabeculae (pls. 67–70A). The trabeculae are rather short in T. willis (pl. 69A), whiplike in S. hardwickei (pl. 70A), or end in a knoblike tip in Euscorpius Thorell, 1876 species (pl. 67A). The bases of the trabeculae tend to be stabilized by small, foldlike ridges continuously merging into the lamellar surface. Branched trabeculae occur sporadically in S. hardwickei.
Distal edges of lamellae
The lamellar edges of S. hardwickei (pl. 70B) and T. willis (pl. 69B) are covered with dense, brushlike bristles. Megacormus granosus (pl. 68B) and Euscorpius species (pl. 67B) display arcuate bowlike structures along the distal lamellar edges.
Book Lungs of Chactidae
The ventral surfaces of the lamellae of the chactid exemplars studied are covered with simple trabeculae (pls. 71–78A), regularly spaced apart. The trabeculae of most chactid exemplars are flexible and end in a knoblike tip that is at most 1.5 times the narrowest diameter of the shaft. Compared with the other chactids observed, the trabeculae are rigid in B. granulatus (pl. 72A).
Distal edges of lamellae
The lamellar edges of most chactid exemplars (pls. 71–78B) display brushlike bristles. However, the bristles are reduced to a sparse, irregular row in N. allenii (pl. 77B). Chactas Gervais, 1844 (pls. 73B, 74B) and Teuthraustes (pl. 78B) possess bow-shaped processes, fusing to form complex arcuate reticulations, along the lamellar edges.
Posterior edge of spiracle
Subconical hillocks are observed along the posterior edges of the spiracles of B. nitidus (pl. 71C) and N. allenii (pl. 77C). These processes are additionally armed with terminal teeth, often arranged in a row, in B. granulatus (pl. 72C), C. raymondhansi, C. reticulatus (pls. 73C, 74C), G. gonzalespongai (pl. 75C), and H. schaumii (pl. 76C). These processes are somewhat elongated, with a flat tip, broadened to a chisel shape, in C. reticulatus (pl. 74C; Kamenz et al., 2005). Distally expanded, clublike processes are observed in T. gervaisii (pl. 78C).
Book Lungs of Superstitioniidae and Troglotayosicidae
The ventral surfaces of the lamellae of A. tartarus (pl. 79A) are folded into small triangular, conelike structures, sometimes fusing into more complex spines. In contrast, the ventral surfaces of the lamellae of S. donensis and B. xambeui (pls. 80A, 81A) display regularly spaced, simple trabeculae with blunt, rounded ends.
Distal edges of lamellae
The distal edges of the lamellae of A. tartarus (pl. 79B) are demarcated by meandering bulges, winding along the edges, similar to the structures observed in Iurus Thorell, 1876 and Calchas Birula, 1899. These bulges leave slender areas, which may contain small spines in between. The edges of the lamellae are covered with arcuate structures, consisting of fused bow-shaped cuticular processes, in S. donensis (pl. 80B). Brushlike bristles cover the lamellar edges of B. xambeui (pl. 81B).
Book Lungs of Vaejovidae
The ventral surfaces of the lamellae of all vaejovid exemplars studied are covered with simple trabeculae (pls. 82–100A), mostly ending in a knoblike tip, which is scarcely wider than the shaft. Single-branched trabeculae are sometimes observed in P. borregoensis (pl. 85A), P. gracilior (pls. 86A, 87A), S. wupatkiensis (pl. 91A), S. vachoni (pl. 92A), S. macrura (pl. 93A), and Vaejovis C. L. Koch, 1836 species (pls. 96–99).
Distal edges of lamellae
Several variations of spiny to bristly lamellar edges occur among the vaejovids (pls. 82–100B). Spiny lamellar edges are observed in P. pumilus (pl. 82B), Paruroctonus (pls. 83–88B), S. wupatkiensis (pl. 91B), S. vachoni (pl. 92B), S. macrura (pl. 93B), V. nitidulus (pl. 98B), and V. spinigerus (pl. 99B). More bristly projections on the lamellar edges occur in all other vaejovid species, except U. mordax (pl. 95B), and may be fused into thicker bundles, e.g., in V. magdalensis (pl. 96B). The bristles on the lamellar edges of P. becki (pl. 83B), P. apacheanus (pl. 89B), and V. longiunguis (pl. 100B) are short, and not distinctly different from the trabeculae on the ventral surface. Additionally, they do not cover the lamellar edges, which thus appear smooth. Uroctonus mordax is exceptional among vaejovids in possessing arcuate structures (pl. 95B), consisting of fused, bow-shaped cuticular processes, along the lamellar edges.
Posterior edge of spiracle
The posterior spiracle edge displays a diversity of structures among Vaejovidae (pls. 82–100C). Shallow hillocks, observed in P. pumilus (pl. 82C), S. wupatkiensis (pl. 91C), and U. mordax (pl. 95C), are laterally expanded in S. wupatkiensis (pl. 91C). Pseudouroctonus (pls. 89C, 90C), S. vachoni (pl. 92C), S. macrura (pl. 93C), U. huachuca (pl. 94C), V. magdalensis (pl. 96C), V. mexicanus (pl. 97C), and V. nitidulus (pl. 98C) possess higher, subconical hillocks on the posterior spiracle edges, which are often broadened to round hillocks or lobes. These structures are often secondarily covered with small, regularly spaced wartlike processes, which are larger and thornlike in P. reddelli (pl. 90C). Massive subconical thorns without spaces cover the hillocks of U. huachuca (pl. 94C) creating a spiked, macelike surface. Primary subconical processes, also covered with secondary wartlike structures, occur on the posterior spiracle edges of V. spinigerus (pl. 99C) and V. longiunguis (pl. 100C). The secondary structures are arranged in lines or ridges from the base to the tip of the subconical processes in V. spinigerus. More complex processes occur on the posterior spiracle edges of all Paruroctonus exemplars studied (pls. 83–88C). These processes are columellar and irregular in cross section, from oval to irregular polygons with sharp or rounded corners. The distal end of these processes form irregular polygons with planar surfaces in P. gracilior (pls. 86C, 87C) and P. stahnkei (pl. 88C). The processes are fairly regularly spaced apart and superficially resemble the hexagonal tiles observed in diplocentrids, liochelids and scorpionids, but their irregular polygonal cross section suggests that they are not homologous with the tiles observed in these scorpionoid families.
Book Lungs of Bothriuridae
All bothriurid exemplars studied possess rigid, simple trabeculae, regularly spaced apart, on the ventral surfaces of the book lung lamellae (pls. 101–119A). In cross section, the trabeculae are constant throughout most of their length, becoming broader at the base, which merges gradually into the lamellar surface. The tip of each trabecula is also expanded into a knoblike disc, the diameter of which is not greater than twice the diameter of the narrowest point of the trabecula, in L. elegans (pl. 109A). The trabeculae of all other bothriurids possess blunt, somewhat rounded tips.
Distal edges of lamellae
The bothriurid exemplars L. elegans (pl. 109B), P. pictus (pl. 113) and U. tregualemuensis (pl. 118B) exhibit an abrupt change from a ventral surface covered with trabeculae to a smooth dorsal surface. However, in most other bothriurid exemplars, the trabeculae on the edge change gradually into elongated and conical spines or attenuated bristles (pls. 101–108B, 110–112B, 114–117B, 119B). At one extreme on the morphological continuum, the spines of psammophilous species such as T. mapuche (pl. 116) and B. ehrenbergii (pl. 105B) are regularly spaced in a single row, and project straight into the atrium. At the other extreme, a bristly lamellar edge is observed in silvicolous species such as C. obscurus (pl. 107B) and T. glasioui (pl. 115B), where the softer, bent bristles form a dense, brushlike surface along the lamellar edges. The lamellae of most bothriurid exemplars exhibit spination somewhere between the two extremes. The bases of the spines may also be fused to restricted ridges along the edge, as observed in B. burmeisteri (pl. 102B). Branched spines occur sporadically on the lamellae of a few species, e.g., C. sulcatus (pl. 108B).
Posterior edge of spiracle
The posterior edge of the spiracle is covered primarily with spinelike processes in all bothriurid exemplars studied (pls. 101–119C), except the two species of Lisposoma Lawrence, 1928. These spines may be rather short, as in B. ferrugineus (pl. 106C) and V. martinezi (pl. 119C), or elongated and hairlike, as in C. pocockii (Kamenz et al., 2005). In many cases, e.g., B. chacoensis (pl. 103C), B. coriaceus (pl. 104C), C. obscurus (pl. 107C), C. sulcatus (pl. 108C), and T. mapuche (pl. 116C), the long spines display a tendency to branch. Well-developed, branched treelike structures occur along the posterior spiracle edges of P. sanmartini (pl. 114C), T. glasioui (pl. 115C), and U. iheringii (pl. 117C). The structures on the posterior spiracle edge of P. iskay (pl. 112C) are flat, and form low hillocks or lobes. Lisposoma species (pls. 109C, 110C) display rigid, flattened or lobelike processes that are strengthened by lateral bulges.
Book Lungs of Urodacidae
Simple, flexible trabeculae cover the ventral surfaces of the lamellae in the Urodacus Peters, 1861 exemplars studied (pls. 120A, 121A). Most trabeculae end in a knoblike tip, but some possess a single distal, perpendicular branch, the diameter of which is narrower than the shaft.
Distal edges of lamellae
Book Lungs of Heteroscorpionidae
The ventral lamellar surfaces of H. opisthacanthoides (pl. 122A) are covered with simple trabeculae. The trabeculae are mostly cylindrical, constant in diameter, and end in a blunt tip. Some trabeculae possess single branches of smaller diameter than the shaft. These branches arise perpendicularly from the shaft of the trabecula. The trabeculae rarely exhibit multiple branches.
Distal edges of lamellae
Brushlike bristles cover the distal edges of the lamellae of H. opisthacanthoides (pl. 122B).
Posterior edge of spiracle
Polygonal columns or chisel-like processes occur on the posterior edge of the spiracles of H. opisthacanthoides (pl. 122C). The polygonal plates on top of the processes are often inclined, such that one side of the plate is fused to the shaft and the opposite side presents a sharp, chisel-like edge. All transitional states between the extremes described above, may be observed side by side along one spiracle edge.
Book Lungs of Hemiscorpiidae
Rigid erect, simple trabeculae with a cylindrical, rodlike shape cover the ventral surfaces of the lamellae of H. lepturus (pl. 123A) and H. tellinii (not shown). The tips of the trabeculae are blunt and slightly rounded.
Distal edges of lamellae
The cuticular projections on the distal lamellar edges of Hemiscorpius Peters, 1861, e.g., H. lepturus (pl. 123B), are rigid, almost conical, sharply pointed spines, often branching apically. At the base, these spines appear to have pierced through the lamellar edges from inside, and abruptly give way to a smooth edge.
Posterior edge of spiracle
The posterior spiracle edge of Hemiscorpius, e.g., H. lepturus (pl. 123C), is covered with hexagonal columns, the distal ends of which are expanded to closely aligned, hexagonal plates (tiles), leaving gaps of constant dimension across the surface.
Book Lungs of Liochelidae
Regularly spaced, simple trabeculae, each with a knoblike tip, occur on the ventral surfaces of the lamellae of all liochelid exemplars studied (pls. 124–138A). As many as three (maximum five) perpendicular branches occur on the distal ends of the trabeculae in Hadogenes Kraepelin, 1894 (pls. 127–129A), I. politus (pl. 130A), O. elatus (pl. 135A), and P. pauliani (pl. 138A). The branches are narrower in diameter than the shaft of the trabeculae and, in most cases, fairly short. The tips of the branches may be clublike or knoblike.
Distal edges of lamellae
The lamellar edges of all liochelid exemplars studied, except Liocheles Sundevall, 1833 species, are densely covered with brushlike bristles (pls. 124–138B). The bristles on the lamellar edges of Hadogenes (pls. 127–129B) and I. politus (pl. 130B) are more rigid and spinelike. Liocheles species (pls. 131–134B), in contrast, display arcuate structures formed by the fusion of bent cuticular processes covering the lamellar edges.
Posterior edge of spiracle
All liochelid exemplars, except Liocheles, possess hexagonal columns on the posterior edges of the spiracles (pls. 124–138C). The distal ends of the columns are expanded into hexagonal plates (tiles) which may be so closely aligned that they form an almost closed surface of facets, separated only by a regular, narrow network of gaps. Liocheles species (pls. 131–134C), however, display chisel-like structures with a broad, flat tip bearing several teeth in one or more irregular rows. The base of these structures is rounded and the tips may be bent posteriorly.
Book Lungs of Diplocentridae
More or less rigid, simple trabeculae cover the ventral surfaces of the lamellae of all diplocentrid exemplars studied (pls. 139–144A). The trabeculae of B. comondae (pl. 139A) are rather short compared with those of D. lesueurii (pl. 141A) and D. mexicanus (pl. 142A), the tips of which are broadened into a knob, at most twice the diameter of the shaft.
Distal edges of lamellae
Posterior edge of spiracle
All diplocentrid exemplars display columns with a hexagonal cross section along the posterior spiracle edges (pls. 139–144C). These columns vary in height from almost flat to three times their average diameter. The distal ends of the columns are expanded into hexagonal plates (tiles), often arranged side by side to form an almost closed surface of facets, separated only by a regular, narrow network of gaps.
Book Lungs of Scorpionidae
The ventral lamellar surfaces of the scorpionid exemplars studied are covered with trabeculae with up to five narrower branches (pls. 145–156A). These branched trabeculae vary from robust rodlike shapes to thinner whiplike structures.
Distal edges of lamellae
The lamellar edges of the scorpionid exemplars (pls. 145–156B) are densely covered with brushlike bristles, which are more sparsely distributed on the lamellar edges of the psammophilous O. holmi (pl. 151B) and more rigid in O. boehmi (pl. 148B).
Posterior edge of spiracle
Columns, which are hexagonal in cross section, cover the posterior spiracle edges of the scorpionid exemplars (pls. 145–156C). The distal ends of these columns are expanded into hexagonal plates (tiles), which may be so closely aligned that they form an almost closed surface of facets, separated only by a regular, narrow network of gaps across the posterior spiracle edge.
During the course of a century, only two studies, by Laurie (1896) and Pavlovsky (1926), investigated and compared the morphology of scorpion book lungs across a range of families, while a few earlier workers (e.g., Lankester, 1883; Berteaux, 1889) studied the morphology of the book lungs in a more limited sample of taxa. Laurie (1896) studied 22 species in 21 genera, whereas Pavlovsky (1926) expanded Laurie's taxon sample to 35 species in 31 genera (table 1). Although these studies were in many ways at the cutting edge of research for their time, the extent to which they can be compared with the results of the present study is, unfortunately, rather limited. Obviously, both authors were dependent on the optical equipment of the time. Many of the character states revealed in the present study cannot be observed, adequately or at all, with standard histological techniques and light microscopy, and it is not surprising that new character states have been discovered, and/or interpretations revised, with the application of SEM. Laurie and Pavlovsky were also limited by the availability of specimens and taxa for observation, necessitating generalizations about characters and their distribution in taxa. Compared with previous studies, the use of multiple exemplars for determining the distribution of character states across higher taxa in the present study is vastly superior to making assumptions based on one or a few representatives.
In spite of these advances and their implications for comparison with earlier literature on the subject, we are nevertheless able to confirm several observations made by previous authors. For example, the general observation by early workers of the occurrence of reticulated lamellae in all buthid scorpions was confirmed in the present study. Lankester (1883: pl. 81) was the first to demonstrate these “reticulate ornaments” in precise illustrations. The reticulation was subsequently reported sporadically in the literature (e.g., Berteaux, 1889; Kaestner, 1940; Rödl et al., 1989), misinterpreted by Peters (1969), in transverse sections, as papillate trabeculae covering both sides of the lamellae, and appeared finally in the first quantitative analysis of scorpion phylogeny, the unpublished Ph.D. dissertation of Stockwell (1989). The two distinct types of reticulation on the lamellar surfaces of buthoids and chaerilids (figs. 15C, D, pls. 2–60A) were not recognized prior to the present study, however.
Trabeculae were first described by Lankester (1883: 378), who observed the combination of reticulation with “punctate ornament in the periphery of the … lamella”. Lankester (1883) was probably referring to the bridging trabeculae (fig. 12), which appear as points in the view from above, but it is unclear what he referred to by “periphery of the lamella”. We prefer the use of “proximal” to emphasize the occurrence of bridging trabeculae primarily in the anterior to medial areas of the lamellae (fig. 5), where the booklike respiratory organs of all chelicerates, including xiphosurans, are flooded with hemolymph. We follow Scholtz and Kamenz (2006) in interpreting this proximal region to be plesiomorphic for arachnids.
Berteaux (1889) was the first to identify and distinguish branched trabeculae (fig. 15B), projecting into the air space, in a scorpionid, Heterometrus cyaneus (C.L. Koch, 1836), as Scorpio indicus (Karsch, 1884), from the simple unbranched trabeculae of other species (fig. 15A). This character state was not noted again until the present study, where it was confirmed in a broader group of scorpionoid taxa, including scorpionids (pls. 145–156A), liochelids (pls. 127–130A, 135A, 138A), and urodacids (pls. 120A, 121A). Pavlovsky's (1926) observations of the occurrence of reticulation (“chitinous network”) on one side and trabeculae (“chitinous columellae”) on the other side of the lamellae of Calchas nordmanni could not be confirmed in our investigations: only the usual covering of trabeculae was observed.
We also disagree with some of the terminology and observations proposed by Laurie (1896) and accepted by Pavlovsky (1926). The terms “spinous lamella” (sensu Laurie, 1896) or “barbate lamina” (sensu Pavlovsky, 1926) are too imprecise to be informative. The distinct kinds of cuticular processes on the lamellar edges were not mentioned by these authors, nor was a distinction made between the trabeculae (fig. 15) and the structures on the lamellar edges (fig. 16), as we have recognized in the present contribution. The terms “barbate” lamellar edges and “spinelets” were applied as vague, all-encompassing descriptors of diverse bristles (fig. 16A), spines (fig. 16B) and thorns (fig. 16C), some of which are probably not homologous structures, and were compared with “arcade” (sensu Laurie, 1896) or “arcuate” (sensu Pavlovsky, 1926) lamellar edges (cf. fig. 16F). The edges of the reticulated lamellae were also poorly characterized by Laurie (1896), although his documentation of arcuate structures was, with one exception, confirmed in the present study. The “arcade” structures on the lamellar edges of Iurus dufoureius (Brullé, 1832), noted by Laurie (1896), are probably misinterpretations of histological sections.
The importance of the cuticular protuberances on the “posterior margin of the stigmata” (posterior spiracle edge, character 3 in Kamenz et al., 2005) was first recognized by Pavlovsky (1926: 135), who defined six distinct states of this character: (1) “smooth margin … [to] slightly ruffled”; (2) “tuberculate margin”; (3) “columellar margin”; (4) “saw-edge, in section resembling a picket-fence with triangular protuberances”; (5) “barbate margin with fine sharp spines”; (6) “stumpy margin with chaetoids in the shape of columellae widening toward the end”. Unfortunately, such precise definitions were not provided for the surfaces and the edges of the lamellae. A smooth edge was not observed in the present study. However, Pavlovsky's (1926) “ruffled” (1) and “tuberculate” (2) states, and probably also his “saw-edge” (4) state, are comparable to the “hillocks” state (fig. 17A) described in the present contribution and previously, as state 1 of character 3, by Kamenz et al. (2005). Pavlovsky's (1926) “columellar margin” (3), “saw-edge” structures (4), and probably his “barbate margin” (5), correspond to the larger “subconical” state described in the present contribution (state 2 of character 3; fig. 17B). We do not distinguish more rounded “subconical” structures from pointed spines in the present study (fig. 17B). Our attention is focused on secondary structures like teeth on the “chisel-like” processes (state 5 of character 3; fig. 17F), which could not have been observed in histological sections with light microscopy, but are clearly visible using SEM. Pavlovsky's character state (5) “barbate margin with fine sharp spines” also corresponds to the “hairlike” structures described by Kamenz et al. (2005) as state 3 of character 3 (fig. 17C). It is not clear whether Pavlovsky (1926) recognized the hexagonal tiles of scorpionids and liochelids, but we presume that his character state (6), “stumpy margin”, is synonymous with our state 6, “hexagonal tiles” (fig. 17G), which are only recognizable as hexagonal in the transverse section of the so-called “chaetoids”, missed in Pavlovsky's (1926) studies.
In conclusion, although our observations and interpretations of character states on the posterior edge of the spiracle depart somewhat from those of earlier workers, there is much overlap. Our advances in the documentation and interpretation of these structures would not be possible without the aid of modern techniques such as SEM, allowing visualization of the complete three-dimensional structure which was not possible 80–120 years ago.
New Phylogenetic Insights
Two distinct types of reticulate venation (ribbed vs. slender; figs. 15C, D) occur on the lamellar surfaces of Buthidae (table 2). The presence of both types of venation in the diverse New World buthid genus Tityus (pls. 46–55A) suggests that this genus and, hence, the New World buthids may be basal and paraphyletic with respect to the Old World buthids, a possibility suggested by others (Fet et al., 2003; Coddington et al., 2004). Two species of Tityus studied during this investigation (T. bahiensis and T. serrulatus, pls. 47A, 54A) possess a state that appears to be intermediate between the two types of lamellar venation in Buthidae (pls. 2–59A), implying a transformation series from ribbed to slender venation. These species of Tityus may share a more recent common ancestor with the Old World buthids than with the other Tityus species studied, which show a ribbed venation pattern similar to that of the New World buthid exemplars of Caribetityus, Microtityus, and Zabius (e.g., pls. 12A, 33A, 58A).
Slender venation (fig. 15C) is observed in all Old World buthids, for which it is hypothesized to be synapomorphic. Slender venation also occurs in Microcharmus (pl. 59A), confirming a widely held opinion that Microcharmidae renders Buthidae paraphyletic (e.g., Coddington et al., 2004; Prendini and Wheeler, 2005) and should be synonymized with the latter (Volschenk et al., in press).
Chaerilus, often considered to be the sister group of all nonbuthid scorpions (Lamoral, 1980; Coddington et al., 2004), possesses the same ribbed venation (pl. 60A) as the New World buthid exemplars of Caribetityus (pl. 12A), Microtityus (pl. 33A), and Zabius (pl. 58A), and most Tityus exemplars (pls. 46A, 48–53A, 55A). This observation suggests that ribbed venation may be plesiomorphic in Buthidae and lends further support to the hypothesis that the New World buthid assemblage may be basal and paraphyletic with respect to the Old World buthids. The presence of ribbed venation in Chaerilus may also support Stockwell's (1989) hypothesis that Chaerilus is the sister group of Buthidae or “Buthoidea”. Alternatively, Chaerilus must have acquired this venation independently from Buthidae. A sister-group relationship between Chaerilidae and Buthidae, based on lamellar venation, would exclude the enigmatic Pseudochactas Gromov, 1998, however, for the lamellar surface of Pseudochactas (pl. 1A) bears no similarity to either type of buthid venation. The structures on the ventral lamellar surfaces of Pseudochactas resemble the typical trabeculae of nonbuthid scorpions and probably represent the plesiomorphic condition for scorpions, based on their occurrence in other arachnids. As with several other characters (Prendini et al., 2006), the lamellar surface structure of Pseudochactas neither confirms nor refutes Soleglad and Fet's (2003) proposal that pseudochactids are the sister group of all other Recent scorpions.
Viewed from the air space, the ventral lamellar surfaces of the remaining nonbuthid scorpion families (Bothriuridae, Chactidae, Diplocentridae, Euscorpiidae, Hemiscorpiidae, Heteroscorpionidae, Iuridae, Liochelidae, Scorpionidae, Scorpiopidae, Superstitioniidae, Troglotayosicidae, Urodacidae, and Vaejovidae) are covered with branched or simple trabeculae. Although truly branched trabeculae occur only in Scorpionidae and Liochelidae (pls. 145–156A, 127–130A, 135A, 138A), a tendency for the trabeculae to branch occurs in all Scorpionoidea sensu stricto, i.e., excluding Bothriuridae, (pls. 120–156A) suggesting that branched trabeculae are synapomorphic for Scorpionoidea s.s. Alternatively, branched trabeculae may be plesiomorphic in Scorpiones or in nonbuthid scorpions. Branched trabeculae may have evolved from trabeculae that interconnect or bridge the air space between adjacent lamellae, and are retained in the proximal region of the book lung, while detaching from one lamellar surface in the distal region of the book lung. Folds or ridges on the ventral sides of the trabeculae could be retained as branches. Similar conditions are observed in mygalomorph spiders (Reisinger et al., 1990) and uropygids (Börner, 1904), where the branched trabeculae develop a network of ridges between them. The position of the papillate trabeculae of scorpions differs from that of tetrapulmonate arachnids, however, in which the trabeculae occur on the dorsal surfaces of the lamellae. It remains unknown as to whether the trabeculae on one major surface of the lamellae are plesiomorphic in Arachnida, requiring rotation of the book lung in scorpions or tetrapulmonates, or evolved convergently in both arachnid lineages.
Considerable variation is observed in the shape of the lamellar edges (table 2). Thorny and/or smooth to wrinkled lamellar edges (fig. 16C, D) occur in buthids, almost always coincident with venation. Although thorns are observed only in buthids with slender venation, it is difficult to identify a group for which this state might be apomorphic. Smooth and wrinkled edges (e.g., fig. 16D), with a gradation of intermediates, are observed in all buthid species with ribbed surface venation (e.g., pls. 12A, 33A, 46–55A, 58A), but also in some buthids with slender venation (pls. 2A, 7A, 13–17A, 21A, 44A). The smooth to wrinkled lamellar edges appear to be plesiomorphic in buthids. The lamellar edges of Chaerilidae, a potential sister group of Buthidae, are exceptional in possessing pillow- or pad-shaped structures (figs. 16G, pl. 60B), unlike those of other scorpions, and apparently autapomorphic. However, dense reticulation, close to the lamellar edges (pl. 60B) of chaerilids, resembles similar venation in New World buthids such as C. elii and T. asthenes (pls. 12B, 46B), further evidence of a basal position for New World buthids and particularly Tityus species within the buthid clade, and also for a potential sister-group relationship between Chaerilus and the buthids.
Bristles and spines on the lamellar edges (e.g., fig. 16A, B) are longer, more slender, and have a weaker, narrower base than thorns. Bristles are typically more curved and flexible than spines, which are rather straight and rigid. These structures occur in most nonbuthid scorpions, including all exemplars of Bothriuridae, Hemiscorpiidae, Heteroscorpionidae, Pseudochactidae, Scorpionidae, Scorpiopidae, Troglotayosicidae, and Urodacidae, and have also been observed in mesothele spiders (Haupt, 2003; C. Kamenz, personal obs.), mygalomorph spiders (C. Kamenz, personal obs.), amblypygids, and uropygids (Scholtz and Kamenz, 2006). Bristles and spines are therefore probably plesiomorphic in scorpions. Bristles or spines on the lamellar edges are present in all liochelids except Liocheles (pls. 124–130B, 135–138B), and in all vaejovids except Uroctonus Thorell, 1876 (pls. 82–94B, 96–100B). The absence of spines may be autapomorphic in both genera. The absence does not support Soleglad and Fet's (2003, 2004) transferral of Uroctonus (pl. 95B) to Chactidae, however, as spines/bristles are present in most Chactidae, and also in Anuroctonus Pocock, 1893 (pl. 61B), Soleglad and Fet's (2003, 2004) putative sister group of Uroctonus. Although most chactid and iurid exemplars possess spines or bristles on the lamellar edges (e.g., pls. 69–72B, 75–77B, 61B, 64B, 65B), two euscorpiid genera, Euscorpius and Megacormus Karsch, 1881, do not (pls. 67B, 68B). The affinities of Troglocormus Francke, 1981 with Scorpiopidae, pointed out by several authors (Soleglad and Sissom, 2001; Soleglad and Fet, 2003) are confirmed by the similarity of the structures on their lamellar edges (pls. 69B, 70B).
Meandering lamellar edges (fig. 16E) are observed in only three genera among the taxon sample investigated for this study: Alacran Francke, 1982 (Supersitioniidae) (pl. 79B), Calchas (pl. 62B) and Iurus (pl. 66B) (Iuridae). These structures may be synapomorphic for Calchas and Iurus and evolved independently in Alacran, or synapomorphic for all three genera.
The lamellar edges of all diplocentrid exemplars (pls. 139–144B), most euscorpiid exemplars (pls. 67B, 68B), some chactid exemplars (pls. 73B, 74B, 78B), Caraboctonus Pocock, 1893 (pl. 63B) (Iuridae), Liocheles (pls. 131–134B) (Liochelidae), Superstitionia Stahnke, 1940 (pl. 80B) (Superstitioniidae), and Uroctonus (pl. 95B) (Vaejovidae) are covered with arcuate structures (fig. 16F), which appear to have evolved independently several times, perhaps in association with a developmental constraint. Little is known about the development and regulation, from transcription of the encoding genes to outgrowth, of cuticular structures like spines or bristles on the lamellar edges. Sanetra et al. (2005) provide a few models of how such processes could be regulated. Epigenetic effects in book lung development have not been described either. Accordingly, all explanations for the distribution of such characters in scorpions are speculative. The possibility that such structures might be associated with environmental conditions like the relative humidity of the microhabitat is also plausible, but remains to be tested.
Posterior edge of spiracle
The processes observed along the posterior spiracle edge are often variable. Different types may occur with transitional stages along a single edge. The character must therefore be scored for the state that is observed at the center of the posterior edge and contacts the anterior edge of the spiracle on closing.
The most typical structures on the posterior spiracle edge of scorpions are simple, cuticular processes, the shape of which varies from shallow hillocks to subconical or pointed spines (table 2; pls. 3–47C, 49–58C, 64C, 65C, 67–71C, 78C, 80–82C, 91C, 95C, 101–108C, 111C, 113C 116C, 119C). Such processes are absent in Pseudochactas (pl. 1C), suggesting that they may be synapomorphic for other scorpions, and hence that Pseudochactas may be basal in Scorpiones, as proposed by Soleglad and Fet (2003). On the other hand, their widespread occurrence in all other scorpion families may suggest that they are plesiomorphic, and absence (“loss”) autapomorphic in Pseudochactas.
Elongated hairs (e.g., fig. 17C) and other, more complex structures (e.g., fig. 17D–L) occur less often, and are probably derived from this generalized condition. One extreme shape among the structures observed on the posterior spiracle edge is the very regular hexagonal tiles (fig. 17G) that occur in all examined scorpionids, diplocentrids, hemiscorpiids, and liochelids (except Liocheles) (pls. 123–130C, 135–156C). The chisel-like structures (fig. 17F) observed in urodacids and Liocheles (pls. 120C, 121C, 132–134C) may represent intermediate states in a transformation between the simple subconical or spinelike structures (fig. 17B) of other scorpions and the hexagonal tiles of other scorpionoids, whereas the chisel-like structures of Heteroscorpion Birula, 1903 (pl. 122C) appear to be very similar to the hexagonal tiles, and may represent the penultimate step in a transformation series. If that were the case, hexagonal tiles would represent a synapomorphy for all scorpionoid families excluding Heteroscorpionidae and Urodacidae, following Prendini (2000, 2003) and Volschenk and Prendini (2008), with an autapomorphic reversal in Liocheles.
The sporadic occurrence of flattened and chisel-like structures is enigmatic. Flattened structures (fig. 17D) may be derived from chisel-like or simple, subconical processes (fig. 17F, B). Treelike or precursor states (e.g., fig. 17H, I) may be apomorphic in Bothriuridae, but their appearance in the family is inconsistent. For example, different states occur in the bothriurid genera, Phoniocercus Pocock, 1893 and Urophonius Pocock, 1893 (pls. 114C, 117C, 118C). A distant relative, Caraboctonus (Iuridae), also possesses these subtree-like structures (pl. 63C), otherwise unknown outside Bothriuridae.
The importance of the book lung morphology of scorpions was underestimated in the past. The tremendous diversity of structures documented in the present study is matched only by the respiratory organs of air breathing crabs (Farrelly and Greenaway, 1992). Although structural variation in the book lungs of scorpions has long been known (Laurie, 1896; Pavlovsky, 1926), modern SEM techniques reveal a much greater diversity of structures and enable them to be described and documented in more detail. It is clear that these structures contain phylogenetically informative variation at multiple branches in the scorpion tree.
One striking example is the surface sculpturing of the respiratory lamellae (Stockwell, 1989). Reticulate venation is observed only in buthoids and chaerilids, whereas papillate (simple or branched) trabeculae occur on the ventral surface of the lamellae of all other scorpion families. Both conditions of the lamellar surface structure show further variation, which may be informative at lower levels in the taxonomic hierarchy. Which of these and other structures described above are apomorphic, and which plesiomorphic, remains to be tested in a phylogenetic analysis by congruence with other characters from diverse sources (internal anatomy, external morphology, behavior and DNA). We hope that the data presented in this atlas will be incorporated into such analyses, and will also stimulate further investigations on the book lungs of scorpions and other arachnids. Future studies should build upon this work, by enlarging the taxon sample investigated, refining the homology statements proposed, defining new ones, and investigating the functionality of the diverse structures identified in the different taxa.
Kamenz is grateful for financial support from the following sources during the course of the study: SYNTHESYS grant FR-TAF-1284 from the European Economic Commission Research Infrastructure Action; an Annette Kade Graduate Fellowship from the AMNH; German Science Foundation grant DFG Scho 442/10-1. Fieldwork during which material, used in this study, was collected by Prendini was financially supported by the following sources: American Arachnological Society; American Museum of Natural History; Foundation for Research Development, South Africa; National Science Foundation, U.S.A. (grants EAR 0228699, EAR 0313698 and BIO-DEB 0413453); Richard Lounsbery Foundation; Skye Foundation and Charitable Trust; Stavros Niarchos Foundation; University of Cape Town. Prendini thanks the following for assistance with permissions, logistics, and participation in fieldwork during which material used in this study was collected, and/or for donating specimens that were used in the study: Adriano Kury, Ahmet Karataş, Alexander Gromov, Alexander Tietz, Andres Ojanguren-Affilastro, Andrew Gluesenkamp, Barney Tomberlin, Boris Striffler, Brian Fisher, the late Bryant Capiz, Camilo Mattoni, Charles Griswold, Charles Siederman, Darrin Vernier, Dietmar Huber, Edmundo González, Eduardo Florez, Elizabeth Scott, Erich Volschenk, Flora Paul, Frank Somma, František Kovařík, Gerbus Müller, Gonzalo Giribet, Halil Koç, Hamid Goodarzi, Jan Ove Rein, Javier Ponce-Saavedra, Jeremy Huff, Joe Bigelow, John Laing, John Visser, José Ochoa, José Soriano, Justin Gerlach, Kanvaly Bamba, Kari McWest, Kazuaki Suzusaki, Kian Wee, Lionel Monod, Lucie Rogo, Marius Burger, Meg Cumming, Michele McCoy, Michelle Nishiguchi, the late N. Adam Locket, Oscar Francke, Peter Sprouse, Piet Swiegers, Quinton and Nicole Martins, R. David Gaban, Randy Mercurio, Ricardo Pinto-da-Rocha, Richard Boycott, Rick West, Rob MacInnes, Rolando Teruel, Severín Tchibozo, Shane Burchfield, Siegfried Huber, Tharina and Chris Bird, Todd Gearheart, Tomás Cekalovic, Valerio Vignoli, W. David Sissom, Warren Savary, Wayne Maddison, Wolfgang Wranik, Yael Lubin. Both authors thank the following for their assistance and advice during the course of the study: Christine Rollard, Mr. Mascarel, Regis Cleva, and Wilson R. Lourenço (MNHN); Angela Klaus and Jacob Mey (AMNH Microscopy and Imaging Facility); Randy Mercurio, Camilo Mattoni, Edmundo González, Erich Volschenk, Jeremy Huff, Lauren Esposito, Lionel Monod, and Ofelia Delgado (AMNH Scorpion Systematics Research Group); Christian Wirkner and Stefan Richter (Friedrich-Schiller-Universität, Jena); Anja Friedrichs, Gabriele Drescher, and Jason Dunlop (MfN); Andrè Reimann, Anke Braband, Carsten Wolff, Caterina Biffis, Ekaterina Ponomarenko, Frederike Alwes, Franziska Knopf, Gerhard Scholtz, Ines Drescher, Juliane Zantke, Nico Küntzel, Petra Ungerer, Renate Mbacke, Tino Pabst, and all other members of the working group Vergleichende Zoologie (HUB); Danilo Harms (FUB); Martin Watz and Siegfried Huber. Finally, we thank Roger Farley and Christian Wirkner for constructive comments and suggestions that greatly improved the manuscript.
Scorpion Taxa and Material Examined in the Present Investigation
Abbreviations for collections as follows: American Museum of Natural History, New York, U.S.A. (AMNH); Humboldt-Universität, Berlin, Germany (HUB); Museum National d'Histoire Naturelle, Paris, France (MNHN); Museum für Naturkunde, Berlin, Germany (ZMB).
Bothriuridae Simon, 1880:
Bothriurus bonariensis (C. L. Koch, 1842): 1 ♀ (AMNH [LP 2165]), Argentina: ex J.O. Rein, 1.X.2002
Bothriurus burmeisteri Kraepelin, 1894: 1 ♀ (AMNH [LP 4258]), Argentina: Río Negro Province: Las Grutas: road to Cerro Banderita [40°45′18.3″S 65°2′38″W], M. Magnanelli and E.G. López, 11.I.2005
Bothriurus chacoensis Maury and Acosta, 1993: 1 ♀ (AMNH [LP 1913]), Argentina: ex F. Somma, VII.1998; 1 ♀ (ZMB 15381), Paraguay: Fiebrig
Bothriurus coriaceus Pocock, 1893: 1 ♂ (ZMB 8322), Chile: Coquimbo, IX.1893; 1 juv. ♂ (AMNH [LP 2391]), Chile: Region IV (Coquimbo): Choapa Province: Los Vilos, 1 km S [31°55.468′S 71°29.202′W], L. Prendini, C. Mattoni and J. Ochoa, 3.XI.2003, collected at night with UV light
Brachistosternus ehrenbergii (Gervais, 1841): 1 ♂ (AMNH [LP 3066]), Peru: Arequipa Departament: Islay Province: Arenales de Iberia, cerca de las lagunas de Mejma, R. Gutierrez and J.A. Ochoa, 2.III.2004
Brachistosternus ferrugineus (Thorell, 1876): 1 ♀ (MNHN RS 0619), Argentina: Presidente Peron Province: Charata, M. Rayano, X.1951
Centromachetes obscurus Mello-Leitão, 1932: 1 ♂ (AMNH [LP 2436]), Chile: Region IX (La Araucanía): Malleco Province: Parque Nacional Nahuelbuta, near campsite [37°49.744′S 73°00.418′W], L. Prendini, C. Mattoni and J. Ochoa, 14.XI.2003, collected at night with UV light and burrow excavation
Centromachetes pocockii (Kraepelin, 1894): 1 ♀ (ZMB 35145), Chile: Schönemann
Centromachetes sp.: 1 ♀ (MNHN RS 6333), Chile: Concepcion Province: Pinares, T. Cekalovic, 30.IX.1967
Cercophonius sulcatus Kraepelin, 1908: 1 ♂ (AMNH [LP 1618]), Australia: Western Australia: Jarrahdale, E.S. Volschenk, 24–25.II.1998, under stone; 1 ♂ (AMNH [LP 2117]), Australia: Western Australia: Perth escarpment [31°35′14.2″S 116°12′14.2″E], E.S. Volschenk and J. Warden, V.1999, collected with UV light in leaflitter
Cercophonius sp.: 2 ♀ (MNHN RS 0571), [Australia]: J. d'Albans, 1888
Lisposoma elegans Lawrence, 1928: 1 ♂ (AMNH [LP 1636]), Namibia: Namib-Naukluft Park, Volstruishoogte, L. Prendini and E. Scott, 18.I.1998
Lisposoma josehermana Lamoral, 1979: 1 juv. ♀ (AMNH [LP 2524]), Namibia: Oshikoto Region: Tsumeb District: Farm Varianto on Elandshoek 771 [19°22.773′S 17°44.456′E], L. Prendini, E. Scott, T. and C. Bird, Q. and N. Martins, 4.I.2004
Orobothriurus alticola (Pocock, 1899): 1 subad. ♂ (AMNH [LP 4309]), Argentina: San Juan Province: between Paso de Agua Negra and Aduana, vega and surrounds [30°17′33.1″S 69°46′45.6″W], C. Mattoni and A. Ojanguren, 27.I.2005, collected with UV light
Pachakutej iskay (Acosta and Ochoa, 2001): 1 subad. ♂ (AMNH [LP 3061]), Peru: Apurmmac Departament: Abancay, Tamburco, J. Achicahuala and J.A. Ochoa, 28.I.2004
Phoniocercus pictus Pocock, 1893: 1 ♀ (MNHN), Chile: Calbuco, 7.XI.1937
Phoniocercus sanmartini Cekalovic, 1968: 1 ♀ (AMNH [LP 1994]), Chile: Valdivia Province: Parque Oncol, Sendero Punucapa, T. Cekalovic, 13.IV.2001
Thestylus glasioui (Bertkau, 1880): 1 ♂ (AMNH [LP 1965]), Brazil: Parque Nacional da Serra dos Órgãos, Teresópolis, Rio de Janeiro, Pinto-da-Rocha, Dietz and Rosa, 23–28.XI.1999
Timogenes dorbignyi (Guérin Méneville, 1843): 1 ♂ (ZMB 31130), Bolivia: Villa Montes, Eisentraut, 5.X.1930; 1 ♂ (MNHN), H. Krieg, 1931
Timogenes mapuche Maury, 1975: 1 ♂ (AMNH [LP 4312]), Argentina: Neuquén Province: Picún Leufú [39°32′13.5″S 69°13′21.8″W], M. Magnanelli and E.G. López, 25.I.2005
Urophonius iheringii Pocock, 1893: 1 ♂ (MNHN RS 4305), Uruguay: Montevideo: Sayago: Bajo Madera, P.R. San Martín, 17.VI.1943; 1 ♀ (MNHN RS 4306), Uruguay: Maldonado Departament: Cerro de las Animas, P.R. San Martín, 9.VIII.1959, bajo piedro; 1 ♀ (AMNH [LP 3457]), Argentina: Buenos Aires Province: Villa Ventana, near Municipal Camping and Arroyo Belisario [38°05′37″S 61°56′10.2″W], C. Mattoni and M. Magnanelli, 13.VII.2004, collected with UV light
Urophonius tregualemuensis Cekalovic, 1981: 1 juv. ♂ (AMNH [LP 5165]), Chile: Region VII: Talca Province: Parque Nacional Altos del Lircay, A. Ojanguren and P. Korob, 16.II.2005
Vachonia martinezi Abalos, 1954: 1 juv. ♀ (AMNH [LP 2441]), Argentina: Balneario El Condor, M. Magnanelli, 5.V.2003
Buthidae C. L. Koch, 1837:
Ananteris cussinii Borelli, 1910: 1 ♂ (AMNH [LP 1716]), Trinidad and Tobago: Trinidad: Mt. St. Benedict [10°39′49″N 61°23′56″W], L. Prendini, 9.VII.1999, collected at night with UV light
Androctonus amoreuxi amoreuxi (Audouin, 1826): 1 ♀ (ZMB 30909), Mauretania: M. Bout and P. Spatz; 1 ♀ (MNHN RS 2034), Algeria: M. Vachon
Androctonus australis australis (Linnaeus, 1758): 1 ♀ (AMNH [LP 1970]), Egypt: ex R. MacInnes, 6.VI.2002; 1 ♀ (MNHN RS 3081), Sahara, Kef el Dor, Sidi bel Abbés, Denier
Androctonus bicolor aeneas C.L. Koch, 1839: 1 ♀ (MNHN), Tunisia: 10.X.1977
Anomalobuthus rickmersi Kraepelin, 1900: 1 ♂ (AMNH [LP 3772]), Kazakhstan: Almaty Area: Zhambyl District: Taukum Desert, S edge, 12 km NNE of Aidarly [44°17′57″N 75°54′40″E], L. Prendini and A.V. Gromov, 27.VI.2003, collected with UV light at night
Apistobuthus pterygocercus Finnegan, 1932: 1 ♀ (AMNH [LP 1795]), United Arab Emirates: ex T. Gearheart, IX.2000
Babycurus buettneri Karsch, 1886: 1 ♂ (AMNH [LP 1744]), Gabon: Province Ogooue-Maritime: Reserve Monts Doudou, 25.2 km 304° NW Doussala [2°13′36″S 10°23′12″E], M. Burger, 14.III.2000
Babycurus jacksoni (Pocock, 1890): 1 ♂ (MNHN RS 1415), Zanzibar: Mrogoro, P. Leroy, 1889
Buthacus arenicola (Simon, 1885): 1 ♀ (AMNH [LP 1973]), Egypt: ex R. MacInnes, 6.VI.2002
Buthacus leptochelys (Ehrenberg, 1829): 1 ♂ (MNHN RS 5456), Morocco: Ouzzina, 27 km S Taouz, 17.V.1970
Butheoloides maroccanus Hirst, 1925: 1 ♂ (MNHN RS 5264), Morocco: 17.V.1955
Butheolus gallagheri Vachon, 1980: 1 ♂ (AMNH [LP 2280]), Oman: ex R. MacInnes, IV.2003
Buthiscus bicalcaratus Birula, 1905: 1 ♂ (MNHN RS 1721), Algeria: Lallanda, El Oued, L. Balozet, XII.1953
Buthus ibericus Lourenço and Vachon, 2004: 1 ♀ (MNHN RS 8198), Spain: Geróna
Buthus occitanus (Amoreux, 1789): 1 ♂ (AMNH [LP 4595]), Senegal: Ndiass, 7 km W [14°41′14.6″N 17°08′37.0″W], J. Huff and V. Vignoli, 10.VII.2005, collected with UV light at night
Caribetityus elii (Armas and Marcano Fondeur, 1992): 1 ♀ (AMNH [LP 3277]), Dominican Republic: La Vega Province: Loma Casabito, Reserva Científíca Ebano Verde, alongside road to transmitter station [19.0375°N 70.5186°W], E.S. Volschenk and J. Huff, 18.VII.2004, 1478 m, pine forest to humid montane forest, hand collected from under stones and logs, and with blacklights
Centruroides exilicauda (Wood, 1863): 1 ♀ (AMNH [LP 4477]), Mexico: Baja California Sur: Municipio Loreto: Loreto, S, ca. 8 km along gravel road to San Javier, from junction with Route 1 [25°59.733′N 111°25.116′W], L. Prendini, E. González, R. Mercurio and W.E. Savary, 8.VII.2005, collected with UV light at night
Centruroides gracilis (Latreille, 1804): 1 ex. (MNHN RS 1077), Colombia: Gervais and Simon; 1 ♀ (AMNH [LP 2306]), Mexico: Tamaulipas: La Pilita, Area Aldama, P. Sprouse, 3.I.2003; 2 ♀ (AMNH [LP 2051]), Mexico: San Luis Potosí: Antena de Microondas de Ciudad Valles [21°58′55″N 99°08′58″W], L. Prendini, J. Soriano and E. Gonzalez, 2.VIII.2002, collected with UV light at night
Centruroides margaritatus margaritatus (Gervais, 1841): 1 ♂ (AMNH [LP 1787]), Honduras: ex R.D. Gaban, III.2001; 1 ♀ (ZMB)
Centruroides schmidti Sissom, 1995: 1 ♀ (AMNH [LP 2070]), Mexico: Veracruz: Estacion de Biologia ‘Los Tuxtlas’, UNAM, J. Ponce and O. Francke, 19.VII.2002, collected with UV light at night
Cicileus exilis (Pallary, 1928): 1 ♀ (MNHN RS 1273), Algeria: Tamanrasset; 1 ♀ (MNHN RS 3223), Central Sahara: Gara Assekrem, Hoggar
Compsobuthus berlandi Vachon, 1950: 1 ♀ (MNHN RS 4910), Algeria: Djanet (Tassili), W border, 29.I.1967
Compsobuthus maindroni (Kraepelin, 1900): 1 ♂ (AMNH [LP 3765]), United Arab Emirates: Ruus Al Jibal Mtn. Range, ca. 12 km WSW of Al Fujayrah, canyon near Hayl Fort [25°05′14″N 56°13′14″E], A.V. Gromov, 30.III.2003, collected with UV light at night
Grosphus flavopiceus Kraepelin, 1900: 1 ♀ (ZMB 10383), Madagascar: Tukar, S.G. Voeltzkow
Grosphus grandidieri Kraepelin, 1900: 1 ♀ (MNHN RS 1336), Madagascar: Valleé de Tiberenova
Grosphus hirtus Kraepelin, 1900: 1 ♀ (AMNH [LP 2774]), Madagascar: Antsiranana Province: Nosy Be, Parc National de Lokobe, 4.95 km 125° ESE Hellville [13°24′56″S 48°18′27.3″E], D. Andriamalala, C. Griswold, H. Ratsirarson and D. Silva, 13.II.2003
Hottentotta conspersus (Thorell, 1876): 1 juv. (AMNH [LP 2627]), Namibia: Kunene Region: Opuwo District: Hartmann's Valley, ca. 39 km N of Orange Drum [17°26.396′S 12°15.868′E], L. Prendini, E. Scott, T. and C. Bird, Q. and N. Martins, 14.I.2004
Hottentotta hottentotta (Fabricius, 1787): 1 subad. ♂ (AMNH [LP 4822]), Benin: Tanogou: Cascade de Tanogou [10°48.12′N 01°26.26′E], V. Vignoli, VI.2005; 1 ♀ (ZMB 10274), Cameroon: Lake Chad, Duma, S.G. Riggenbach, 17–20.VI.1909
Hottentotta jayakari (Pocock, 1895): 1 subad. ♀ (HUB), Yemen: 2004
Isometroides angusticaudis Keyserling, 1885: 1 ♀ (AMNH [LP 2110]), Australia: South Australia: Coolton National Park [34°12′40.5″S 140°37′42.2″E], E.S. Volschenk and J. Tregear, 9.XII.1998, collected with UV light
Isometrus maculatus (DeGeer, 1778): 1 ♀ (AMNH [LP 1788]), São Tomé and Principé: São Tomé: Praia du Mutamba [00°23′45.5″S 006°36′19.1″E], J.M. Ledford, 2.IV.2001; 1 ex. (MNHN RS 0952), Liberia: Monrovia; 1 ♀ (ZMB 8199), Jahuit, Bartels, 7.II.1900
Karasbergia methueni Hewitt, 1913: 1 ♂ (AMNH [LP 1724]), South Africa: Northern Cape Province: Lekkersing, G.J. Müller et al., 16.I.1999, collected with UV light at night
Leiurus quinquestriatus hebraeus (Birula, 1908): 1 ♀ (MNHN RS 6484), Oman: Masirah Island, R.J. Parker, 17.XII.1972
Leiurus quinquestriatus quinquestriatus (Ehrenberg, 1828): 1 ♀ (AMNH [LP 1530]), Egypt: ex B. Capiz, VII.1998
Liobuthus kessleri Birula, 1898: 1 ♂ (AMNH [LP 3790]), Kazakhstan: South Kazakhstan Area: Chardara District: 3 km W of Chardara [41°16.106′N 67°53.228′E], L. Prendini and A.V. Gromov, 20.VI.2003, collected with UV light at night
Lychas mucronatus (Fabricius, 1798): 1 ♀ (MNHN RS 1437), Indonesia: Java; 1 ♀ (MNHN RS 1474), China: Baie d'Alones, Dawydoff, X.1934
Lychas obsti Kraepelin, 1913: 1 ♂ (AMNH [LP 1797]), Kenya: ex J. Ove Rein
Lychas scutilus C.L. Koch, 1845: 1 ♀ (ZMB 11341), Indonesia: Heinroth, 28.VIII.1902
Lychas tricarinatus (Simon, 1884): 1 ex. (MNHN RS 1440), India: North Arkof, Maindron
Lychas sp.: 1 ♀ (AMNH [LP 1646]), Australia: Queensland: Undara National Park [18°12′32.2″S 144°38′30.6″E], E.S. Volschenk, T. Heslin and C. Berridge, 26.III.1999, collected with UV light in leaflitter
Mesobuthus caucasicus parthorum Pocock, 1889: 1 ex. (MNHN RS 4666), Iran: Chahpuze (Asarhaydjan), Habibi, 1968
Mesobuthus eupeus thersites (C. L. Koch, 1839): 1 ♂ (AMNH [LP 3810]), Kazakhstan: South Kazakhstan Area: Chardara District: 3 km W of Chardara [41°16.106′N 67°53.228′E], L. Prendini and A.V. Gromov, 20.VI.2003, collected with UV light at night
Mesobuthus gibbosus (Brullé, 1832): 1 ♀ (MNHN RS 7010), Greece: Aegean Sea: Arkos Is., Pili, Constantinos, 12.VIII.1972
Microtityus rickyi Kjellesvig-Waering, 1966: 1 ♀ (AMNH [LP 1717]), Trinidad and Tobago: Trinidad: Gaspar Grande Island, L. Prendini, 7.VII.1999, collected with UV light at night
Odontobuthus doriae (Thorell, 1876): 1 ♀ (MNHN RS 1823), Iran: Kashan; 1 ♀ (AMNH [LP 2908]), Iran: Yazd Province: Ardakan, 10 km E [32°18.626′N 54°15.133′E], V. Vignoli and P. Crucitti, 11.IV.2004
Odonturus dentatus Karsch, 1879: 1 ♂ (AMNH [LP 1578]), Tanzania: ex R.D. Gaban, XI.1999
Orthochirus innesi Simon, 1910: 1 ♀ (MNHN RS 5440), Morocco: Taouz (environs), 27.III.1970; 1 ♀ (AMNH [LP 4407]), Oman: ex A. Tietz, VIII.2005
Orthochirus scrobiculosus scrobiculosus (Grube, 1873): 1 ♀ (AMNH [LP 3775]), Kazakhstan: South Kazakhstan Area: Chardara District: 3 km W of Chardara [41°16.106′N 67°53.228′E], L. Prendini and A.V. Gromov, 20.VI.2003, collected with UV light at night
Parabuthus leiosoma (Ehrenberg, 1828): 1 ♀ (AMNH [LP 1845]), Kenya: Nguruman, Rift Valley, X.1999
Pseudolychas pegleri (Purcell, 1901): 1 ♀ (AMNH [LP 1326]), Swaziland: Mlawula Nature Reserve: Sara Camp [26°11′44″S 31°59′24″E], L. Prendini, G. Giribet and R. Boycott, 2.IV.2001, collected with UV light at night
Rhopalurus acromelas Lutz and Mello, 1922: 1 ♀ (MNHN), Brazil: Brasilia, Barreiras, W.R. Lourenço, 3.X.1975
Rhopalurus bonettii Armas, 1999: 1 juv. ♂ (AMNH [LP 3267]), Dominican Republic: Pedernales Provence: Parque Nacional Jaragua, Cabo Rojo [17.8958°N 71.6600°W], E.S. Volschenk and J. Huff, 9.VII.2004, collected with UV light
Rhopalurus junceus (Herbst, 1800): 1 ♀ (MNHN RS 3288), Cuba: Etangra Samorrostra, J. Négre, 21.V.1950; 1 juv. (AMNH [LP 1517]), Cuba: Santiago de Cuba Province: La Socapa, 10 km SW of Santiago de Cuba, R. Teruel, 9.IV.1999
Rhopalurus laticauda Thorell, 1876: 1 ♀ (AMNH [LP 2462]), Venezuela: Caracas, C. Siederman, 2001
Rhopalurus princeps (Karsch, 1879): 1 ♂ (AMNH [LP 1566]), Dominican Republic: Pedernales Province: Manuel Goja, 3.9 km N, D. Huber, 9.V.1998
Rhopalurus rochae Borelli, 1910: 1 ♂ (AMNH [LP 1582]), Brazil: Paraiba: Soledade [7°02.118′S 36°27.311′W], A. Kury and A. Giupponi, 16.III.1999
Tityobuthus baroni (Pocock, 1890): 1 ♂ (AMNH [LP 1941]), Madagascar: Antsiranana Province: Nosy Be, Réserve Naturelle Intégrale de Lokobe, 6.3 km 112° ESE Hellville [13°25′10″S 48°19′52″E], B.L. Fisher, C.E. Griswold et al., 19.III.2001
Tityus asthenes Pocock, 1893: 1 ♀ (AMNH [LP 1831]), Ecuador: Sarayacu, Rio Bobonaza and Capahuari, M. Peprný, VI.1999
Tityus bahiensis eickstedtae (Lourenço, 1982): 1 ♀ (AMNH [LP 1596]), Brazil: ex Instituto Butantan via R. Pinto-da-Rocha, VIII.1999
Tityus bolivianus Kraepelin, 1895: 1 ♂ (AMNH [LP 4249]), Bolivia: Potosí Department, Comunidad Phalapaya, 10 km E of Betanzos [19°36′21.6″S 65°23′54.7″W], C. Mattoni, A. Ojanguren and J. Ochoa, 9.I.2005, collected with UV light
Tityus cambridgei Pocock, 1897: 1 ex. (MNHN RS 5252), French Guiana: Saul, A.S. Balachowsky, 27.X.1969; 1 ♀ (AMNH [LP 3649]), French Guiana: Maripasoula: Saul, Chez Fred's [3°37′42.0″N 53°12′40.0″W], J. Huff, 14.XII.2004, collected with UV light; 1 ♂ (AMNH [LP 3434]), French Guiana: Roura District: Kaw Mountains, NE slopes, R.C. West, 24.IX.2004
Tityus clathratus C. L. Koch, 1844: 1 ♀ (AMNH [LP 1567]), Trinidad and Tobago: Trinidad: Gaspar Grande Island, L. Prendini, 7.VII.1999, collected with UV light at night
Tityus confluens Borelli, 1899: 1 ♀ (AMNH [LP 2938]), Argentina: Chaco: Parque Nacional Chaco, A. Ojanguren, F. Labarque, C. Grismado and L. Compagnucci, 26.II.2004
Tityus discrepans (Karsch, 1879): 1 ♀ (AMNH [LP 1547]), Venezuela: Caracas, M.A. Gonzalez-Sponga, XI.1998
Tityus melanostictus Pocock, 1893: 1 ♀ (AMNH [LP 1504]), Trinidad and Tobago: Trinidad: Gaspar Grande Island, L. Prendini, 7.VII.1999, collected with UV light at night
Tityus serrulatus Lutz and Mello, 1922: 1 ♀ (AMNH [LP 1597]), Brazil: ex Instituto Butantan via R. Pinto-da-Rocha, VIII.1999; 1 ♀ (MNHN), Brazil: Butantan, W. Bücherl, 13.XII.1961
Tityus silvestris Pocock, 1897: 1 ♂ (AMNH [LP 3643]), French Guiana: Maripasoula, Saul, Campsite Chez Fred's [03°37′42.0′N 53°12′40.0″W], J. Huff, 14–15.XII.2005, manicured landscape surrounded by primary tropical rainforest, hand collected using UV light at night; 1 ♀ (ZMB), Surinam: Paramaribo, S.V. Heller, I.1908
Uroplectes flavoviridis Peters, 1861: 1 ♀ (AMNH [LP 1707]), Zimbabwe: Highlands, Harare, M. Cumming, 24.I.1999
Uroplectes occidentalis Simon, 1867: 1 ♀ (ZMB 7599), Cameroon: Jaunde, Zenker
Uroplectes planimanus (Karsch, 1879): 1 ♀ (MNHN [ANG 1839-1]), Angola
Vachoniolus globimanus Levy, Amitai and Shulov, 1973: 1 ♂ (AMNH [LP 3767]), United Arab Emirates: Rub' Al Khali Desert, ca. 17 km SE of Dubai [25°10′04″S 55°28′07″E], A.V. Gromov, 28.III.2003
Zabius fuscus (Thorell, 1876): 1 juv. ♀ (AMNH [LP 1759]), Argentina: Córdoba: La Quebrada, M. López, 8.XI.1999
Chactidae Pocock, 1893:
Broteochactas delicatus (Karsch, 1879): 1 ♂ (MNHN RS 3392), French Guiana: Camopi, Valleé de l'Oyapock, 18.XII.1948; 1 ♂, 1 ♀, 1 juv. ♂ (AMNH), French Guiana, 2005
Broteochactas nitidus Pocock, 1893: 1 ♀ (AMNH [LP 1511]), Trinidad and Tobago: Trinidad: Mt. St. Benedict [10°39′49″N 61°23′56″W], L. Prendini, 28.VI.1999, collected with UV light at night
Brotheas gervaisii Pocock, 1893: 1 ♂ (MNHN RS 8508]), French Guiana: Rive droite de l'Arataye en aral du Sant Parané, J.P. Gasc, I.1981; 1 ♀ (ZMB 15360), Surinam: Paramaribo, Heller, 1909; 1 ♀ (MNHN RS 7389); 1 ex. (MNHN)
Brotheas granulatus Simon, 1877: 1 ♂ (MNHN RS 8508]), French Guiana: Rive droite de l'Arataye en aral du Sant Parané, J.P. Gasc, I.1981; 1♀ (AMNH [LP 3439]), French Guiana: Roura District: Kaw Mountains, NE slopes, R.C. West, 24.IX.2004; 1 ex. (MNHN)
Chactas gestroi Kraepelin, 1912: 1 ♀ (MNHN RS 0760), Colombia: Merida, Simon
Chactas raymondhansi Francke and Boos, 1986: 1 subad. ♀ (AMNH [LP 1586]), Trinidad and Tobago: Trinidad: Mt. El Tucuche summit, L. Prendini, 8.VII.1999
Chactas reticulatus Kraepelin, 1912: 1 ♀ (MNHN RS 0775), Colombia: Angelopolis, L. Fuhrmann, 1910; 1 ex. (MNHN), Colombia: Angelopolis, II.1998
Guyanochactas gonzalezspongai (Lourenço, 1983): 1 ♀ (AMNH [LP 3435]), French Guiana: Roura District: Kaw Mountains, NE slopes, R.C. West, 24.IX.2004; 1 ex. (MNHN)
Hadrurochactas schaumii (Karsch, 1880): 1 ♀ (AMNH [LP 3680]), French Guiana: Approuague-Kaw: Kaw mountains, area around Amazone Nature Lodge [4°33′35.0″N 52°12′25.3″W], J. Huff, 21.XII.2004; 1 ex. (MNHN)
Nullibrotheas allenii (Wood, 1863): 1 juv. ♂ (AMNH [LP 2869]), México: Baja California Sur: El Tecolote [24°20.259′N 110°18.580′W], R. Mercurio, M. Nishiguchi, et al., 21.V.2004, collected with UV light
Teuthraustes atramentarius Simon, 1878: 1 ♀ (MNHN RS 0784), Ecuador: Riobamba, G. Rivet, 1901
Teuthraustus gervaisii (Pocock, 1893): 1 ♀ (AMNH [LP 1855]), Ecuador: Guyallabamba, M. Peprný, VI.1999
Chaerilidae Pocock, 1893:
Chaerilus truncatus Karsch, 1879: 1 ♂ (AMNH [LP 2197A]), Nepal: Naudanda, Kaski, Gandaki (west Nepal), Tillack, Grossmann and Tillack, VII.1999
Chaerilus sp.: 1 ♀ (MNHN RS 0607), Indonesia
Diplocentridae Karsch, 1880:
Bioculus comondae Stahnke, 1968: 1 juv. ♀ (AMNH [LP 4738]), Mexico: Baja California Sur: Municipio Loreto: Loreto, S, ca. 8 km along gravel road to San Javier, from junction with Route 1 [25°59.733′N 111°25.116′W], L. Prendini, E. González, R. Mercurio and W.E. Savary, 8.VII.2005, collected with UV light at night
Cazierius gundlachii (Karsch, 1880): 1 ♂ (AMNH [LP 1779]), Cuba: Santiago de Cuba Province: Quintero, Santiago de Cuba, R. Teruel, 15.IV.1999
Didymocentrus lesueurii (Gervais, 1844): 1 ♀ (AMNH [LP 3638]), Martinique: E of Anses-d'Arlet, 6.5 km W of Le Diamant [14°29′37.6″N 61°04′16.0″W], J. Huff, 7.XII.2004; 1 ex. (MNHN), Martinique
Diplocentrus mexicanus mexicanus Peters, 1861: 1 ♀ (AMNH [LP 2055]), Mexico: Oaxaca: 3.7 km N El Moral [17°30.134′N 96°56.091′W], L. Prendini, O. Francke, E. Gonzalez and J. Ponce, 23.VII.2002
Diplocentrus tehuacanus Hoffmann, 1931: 1 ♂ (MNHN RS 4281), Mexico
Diplocentrus whitei (Gervais, 1844): 1 ♂ (MNHN RS 3350), Mexico: Genin, 1922
Diplocentrus zacatecanus Hoffmann, 1931: 1 ♂ (MNHN RS 4284), Mexico: Zacatecas: Mazapil, A. Diaz N., 4.IX.1963
Heteronebo granti Pocock, 1899: 1 juv. ♀ (AMNH [LP 1634]), Yemen: Abd-al-Kuri Island, W. Wranik, II.1999
Nebo hierichonticus (Simon, 1872): 1 juv. ♂ (AMNH [LP 1561]), Israel, Mitrani Center for Desert Ecology, ex Y. Lubin, VI.1998; 1 ♂ (MNHN RS 4541), Jordan, D. Wahbek, III.1966; 1 ♀ (MNHN), Israel: Ein Geddi, J. Wahrman, 8.IV.1951
Euscorpiidae Laurie, 1896:
Euscorpius carpathicus candiota Birula, 1903: 3 ♀ (HUB), Greece: Crete, 1999
Euscorpius flavicaudis (DeGeer, 1778): 1 ex. (MNHN)
Euscorpius italicus (Herbst, 1800): 1 juv. ♀ (HUB), Italy, 2006
Megacormus gertschi Díaz Najera, 1966: 1 ♂ (MNHN RS 0787) Mexico: Muyoapan
Megacormus granosus (Gervais, 1843): 1 ♀ (AMNH [LP 2074]), Mexico: Veracruz: Camino a Cañada Blanca [18°55.707′N 96°51.434′W], E. Gonzalez Santillan, 18.VII.2002, collected with UV light at night
Troglocormus willis Francke, 1981: 1 juv. ♂ (AMNH), Mexico: Tamaulipas: Cueva del Brinco, P. Sprouse, VII.1978
Hemiscorpiidae Pocock, 1893:
Hemiscorpius lepturus Peters, 1861: 1 ♀ (AMNH [LP 4343]), Iran: Khouzestan Province: Andimeshk, H.R. Goodarzi, V.2005
Hemiscorpius tellinii Borelli, 1904: 1 ♀ (MNHN RS 0560), Ethiopia; 1 ♀ (MNHN RS 0607)
Heteroscorpionidae Kraepelin, 1905:
Heteroscorpion opisthacanthoides (Kraepelin, 1896): 1 subad. ♂ (AMNH [LP 2706]), Madagascar: Antsiranana Province: Montagne de Français, 7.2 km 142° SE Antsiranana ( = Diego Suarez) [12°19′22″S 49°20′17″E], B.L. Fisher, C.E. Griswold et al., 22.II.2001; 1 ♀ (MNHN RS 4813), Madagascar: Nossi-Komba, Millot, 1945
Iuridae Thorell, 1876:
Anuroctonus phaiodactylus (Wood, 1863): 1 subad. ♀ (AMNH [LP 4970]), U.S.A.: California: Inyo County: Death Valley National Park: South Pass, junction of Saline Valley Road and Hunter Mountain Road [36°31.441′N 117°32.894′W], R. Mercurio and L. Prendini, 4.IX.2005, burrow excavation
Anuroctonus pococki Soleglad and Fet, 2004: 1 ♂ (MNHN RS 6207), U.S.A.: California: San Diego: Mount Soleglad, S.C. Williams, 21.III.1965
Calchas nordmanni Birula, 1899: 1 ♀ (MNHN RS 6452), Turkey: Biledjik, 23.IV.1971; 1 ♀ (AMNH [LP 2246]), Turkey: Artvin: Ardanug, A. Karataş, 26.VIII.2001; 1 ♂ (AMNH [LP 4333]), Turkey: Antep-Sehitkamil: Incesu Köyü, E. Aydin, 7.V.2005
Caraboctonus keyserlingi Pocock, 1893: 1 ♀ (MNHN RS 8561), Chile: Coquimbo Province: Bajada El Teniente, km 330, T. Cekalovic, 13.IX.1964; 1 ex. (AMNH [LP 3686]), Chile: Aguas Claras, near Zapallar, J.S. Ascher, 1.XII.2004; 1 ♂ (MNHN RS 8571), 5.IX.1968
Hadruroides charcasus (Karsch, 1879): 1 ♀ (MNHN RS 714), Peru: Baños, P.O. Simons; 1 ♀ (AMNH [LP 1555]), Peru: ex R.D. Gaban, VI.1999; 1 ♀ (AMNH [LP 1575]), Peru: ex T. Gearheart, 16.V.2000
Hadrurus concolorous Stahnke, 1969: 1 ♀ (ZMB 15220), Mexico: Baja California: San José, v. Blücher
Hadrurus hirsutus (Wood, 1863): 1 ♂ (AMNH [LP 3131]), Mexico: Baja California Sur: La Paz, 75 km NW [24°05′56.2″N 110°45′41″W], O. Francke, E. González and A. Valdez, 7.VII.2004, collected with UV light at night
Hadrurus spadix Stahnke, 1940: 1 ♀, 1 ♂ (MNHN RS 6194), U.S.A.: California: Inyo County: Saline Valley: Grapevine station 44 Canyon road, B. Banta, 4.VI.1960, collected with a pit trap
Iurus dufoureius asiaticus Birula, 1903: 1 ♂ (MNHN RS 5168), Turkey: B.H. Lamoral, 1980; 1 juv. (HUB), Turkey: Silifke, Turkish Riviera, Cennet Sinkhole [36°27′08.2″N 34°06′22.3″E], S. Huber, 4.IV.2005
Iurus dufoureius dufoureius (Brullé, 1832): 1 ♂ (ZMB 7497), Cyprus: Rolle; 1 ♀ (MNHN RS 2977]), Greece: Crete, K. Lindberg, 1979
Liochelidae Fet and Bechly, 2001 (1879):
Cheloctonus anthracinus warreni Hewitt, 1931: 1 ♀ (MNHN RS 0374 [NM 700]), South Africa: KwaZulu-Natal Province: Trurence
Cheloctonus jonesii Pocock, 1892: 1 ♂ (ZMB 35141), South Africa: Limpopo Province: Lekgalameetse, Koch, 18.XII.1995; 1 juv. ♀ (AMNH [LP 1558]), South Africa: Kwazulu-Natal Province: Weenen Nature Reserve, L. Prendini and E. Scott, 6.XII.1998, burrow excavation; 1 ex. (MNHN RS 6612), Republic of South Africa: Ubombo, J.P. Gasc, 5–7.X.1973
Chiromachus ochropus (C.L. Koch, 1837): 1 ♂ (ZMB 15169), Seychelles, Brauer; 1 ♀ (MNHN RS 0383]), Seychelles; 1 juv. ♀ (AMNH [LP 2189]), Seychelles: Fregate Island, J. Gerlach, 1.X.2002
Hadogenes trichiurus trichiurus (Gervais, 1843): 1 ♂ (AMNH [LP 3402]), South Africa: Eastern Cape Province: Graaff-Reinet District: Ouberg Pass, J. Visser, 26.IV.2004
Hadogenes troglodytes troglodytes (Peters, 1861): 1 ♂ (AMNH [LP 1315]), South Africa: Limpopo Province: Kruger National Park, Tshanga Lookout Point [23°13.73′S 31°14.28′E], L. Monod and B. Striffler, IV.2001; 1 ♀ (MNHN)
Hadogenes sp.: 1 ♀ (AMNH [LP 1794]), Tanzania: ex T. Gearheart; 1 ♀ (ZMB 7465); 1 ♂ (HUB)
Iomachus politus Pocock, 1896: 1 ♂ (AMNH [LP 1514]), Tanzania: ex T. Gearheart, 4.VI.1999
Liocheles australasiae (Fabricius, 1775): 1 ♀ (AMNH [LP 1854]), India: Andaman Islands: Havelock Island, III.1999; 1 ♀ (AMNH [LP 4764]), Malaysia: Selangor, Batu Caves area [3.244°N 101.695°E], W. Maddison, D. Li, I. Agnarsson and J.X. Zhang, 19.V.2005; 1 ♀ (MNHN RS 0454), Mariana Islands, 5–6.III.1888; 1 ♀ (MNHN RS 3236)
Liocheles karschii (Keyserling, 1885): 1 ♂ (ZMB 30838), Papua New Guinea: Kaiserins.
Liocheles waigiensis (Gervais, 1843): 1 ♀ (AMNH [LP 1502]), Australia: Queensland: Connondale National Park [26°41′50.0″S 152°33′12.4″E], E.S. Volschenk and P.A. Aitken, 17.III.1990, collected with UV light; 1 ♀ (MNHN RS 8350), New Caledonia: Ova Tom, P. Boachet, 16.IX.1979
Opisthacanthus africanus Simon, 1876: 1 ♀ (MNHN RS 0550), French Congo: Brazzaville, Roubond and Weiss, 15.III.1907
Opisthacanthus elatus (Gervais, 1844): 1 ♂ (MNHN RS 0301), 1922; 1 ♀ (AMNH [LP 1837]), Panama: Soberalie National Park, M. Makovec, 15.X.2000
Opisthacanthus lecomtei (Lucas, 1858): 1 ♀ (ZMB), Cameroon
Opisthacanthus madagascariensis Kraepelin, 1894: 1 ♀ (AMNH [LP 2799]), Madagascar: Mahajanga Province: Mahavavy River, 6.2 km 145° SE Mitsinjo [16°03′06″S 045°54′30″E], B.L. Fisher, C.E. Griswold et al., 1.XII.2002; 1 ♀ (MNHN RS 0256), Madagascar: Mahafaly, M. Bastard
Opisthacanthus validus Thorell, 1876: 1 juv. ♀ (AMNH [LP 3379]), South Africa: Eastern Cape Province: Humansdorp District: Swart River [34°04′S 24°54′E], J. Visser, 23.VII.2004
Palaeocheloctonus pauliani Lourenço, 1996: 1 ex. (MNHN RS 3970), Madagascar: Concession Wilmain, Tulear, Emerit, 30.XI.1962
Microcharmidae Lourenço, 1996:
Microcharmus sp.: 1 ♀ (AMNH [LP 1769]), Madagascar: Antsiranana Province: Réserve Spéciale Manongarivo, 10.8 km SW Antanambao [13°57.7′S 48°26.0′E], B.L. Fisher, 8.XI.1998
Pseudochactidae Gromov, 1998:
Pseudochactas ovchinnikovi Gromov, 1998: 1 juv. ♂ (AMNH [LP 2303]), 1 juv. (AMNH), Uzbekistan: Surkhandarya Area: Dikhana Canyon, ca. 5 km WSW Akmechet (Oqmachit) village, foothills on E slopes of Babatag Mtn. Range [38°01.638′N 68°15.198′E], L. Prendini and A.V. Gromov, 20.V.2003, collected with UV light
Scorpionidae Latreille, 1802:
Heterometrus fulvipes (C. L. Koch, 1837): 1 ♀ (AMNH [LP 4324]), India: Tamil Nadu: Kancheepuram District: Nemmali, 45 km from Chennai, on the eastern coastline, H.A. Vadivelu, A. and R. Ali and F. Paul, 30.V.2005
Heterometrus longimanus (Herbst, 1800): 1 ♀ (ZMB 30849), Indonesia: Sumatra: Padang, Tiefsee, 1914
Heterometrus spinifer (Ehrenberg, 1828): 1 ♂ (AMNH [LP 1604]), Singapore, K. Wee, IX.1998
Heterometrus swammerdami Simon, 1872: 1 ♂ (AMNH [LP 1607]), India: ex T. Gearheart
Heterometrus sp.: 1 ex. (MNHN)
Opistophthalmus boehmi (Kraepelin, 1896): 1 ♀ (AMNH [LP 1827]), Tanzania: ex K. Suzusaki, 27.II.2000
Opistophthalmus capensis (Herbst, 1800): 2 ♀ (AMNH [AH 1266, 1268]), South Africa: Western Cape Province: Strand District: Base of Koeëlberg, 20 km S Strand, A. Harington, 13.I.1979
Opistophthalmus carinatus (Peters, 1861): 1 ♀ (ZMB 14951), Namibia; 1 juv. ♂ (MNHN), Kalahari, B. Le Bret.
Opistophthalmus fitzsimonsi Hewitt, 1935: 1 juv. (MNHN), Kalahari
Opistophthalmus glabrifrons Peters, 1861: 1 ♀ (AMNH [LP 1074]), South Africa: Northern Province: Soutpansberg District: Crystal Salt Works, near firing range [22°58′S 29°20′E], L. Prendini and J. Laing, I.1996
Opistophthalmus holmi (Lawrence, 1969): 1 ♀ (AMNH [LP 1082]), Namibia: Karas Region: Lüderitz District, Diamond Area 1: Namib-Naukluft Park, Koichab riverbed, dunes on northern bank [26°13.41′S 15°59.24′E], L. Prendini, E. Scott and P. Swiegers, 3.I.1998
Pandinus cavimanus (Pocock, 1888): 1 ♀ (AMNH [LP 3259]), Tanzania
Pandinus imperator (C.L. Koch, 1841): 1 ♀ (AMNH [LP 4836]), Benin: Bembereké: Riviere Dere, Foret classe d'Ouenou-Benou, Gando village [10°12.09′N 02°39.05′E], V. Vignoli and S. Tchibozo, 3.VI.2005; 1 ♂ (MNHN), Sudan: Delami, W. Ruttledge, 20.V.1927
Pandinus viatoris (Pocock, 1890): 1 ♀ (ZMB 15056), Mozambique: Tiesler
Scorpio maurus fuliginosus (Pallary, 1928): 1 ♂ (AMNH [LP 1930]), Morocco: Haha Mountains (western outliers of Atlas), ca. 10 km N Isk/Immouzer, ca. 60 km N Agadir, S. Huber, 21.VII.2000; 1 ex. (MNHN RS 1200), Morocco: Kasba d'Asni, J. de Lépiney, 31.V.1939
Scorpio maurus fuscus (Ehrenberg, 1829): 1 ♂ (AMNH [LP 1556]), Israel: Mitrani Center for Desert Ecology, ex Y. Lubin, VI.1998
Scorpio maurus palmatus (Ehrenberg, 1828): 1 ♀ (AMNH [LP 1532]), Egypt: ex D. Taylor, X.1997
Scorpio maurus subsp.: 1 ♀ (MNHN), Algeria: Manoc; 1 ex. (ZMB)
Scorpiopidae Kraepelin, 1905:
Scorpiops hardwickei (Gervais, 1843): 1 ♀ (MNHN RS 0722), Himalaya: Rhala, G. Babault, 1915; 1 ♀ (MNHN RS 0725), India: Himalaya: Calcutta, Simon
Scorpiops petersii Pocock, 1893: 1 ex. (ZMB 3063), India: Himalaya, Trochnow
Superstitioniidae Stahnke, 1940:
Alacran tartarus Francke, 1982: 1 ♀ (AMNH [LP 3499]), México: Oaxaca: Municipio San Miguel: Cueva de Escorpion [18.1065°N 96.7982°W], A. Gluesenkamp, P. Sprouse and C. Savvas, 18.IX.2004
Superstitionia donensis Stahnke, 1940: 1 ♂, 2 ♀ (AMNH [LP 3420]), U.S.A.: Arizona: Piñal County: Superstition Mountains, D. Vernier, XI.2003
Troglotayosicidae Lourenço, 1998:
Belisarius xambeui Simon, 1879: 1 ♀ (MNHN RS 7743), Spain: Mataro, J. Nègre, 31.VIII.1948; 1 ♀ (MNHN RS 0801), Spain: Gerona: Camprodon, J. Mateu, IX.1954
Urodacidae Pocock, 1893:
Urodacus manicatus (Thorell, 1876): 1 ♀ (ZMB 14909), Australia: Germantown, Oschatz, 1910
Urodacus novaehollandiae Peters, 1861: 1 ♂ (AMNH [LP 1658]), Australia: Western Australia: Jarrahdale, E.S. Volschenk, 25.II.1998
Urodacus yaschenkoi (Birula, 1903): 1 ♂ (AMNH [LP 1659]), Australia: South Australia: Berri, N.A. Locket and E.S. Volschenk, 24.IX.1997
Urodacus sp.: 1 ♂ (MNHN RS 8352), Australia: Western Australia: S.D. Bradshaw, IV.1980
Vaejovidae Thorell, 1876:
Paravaejovis pumilis (Williams, 1970): 1 ♂ (AMNH), México: Baja California Sur: Ciudad Constitucion, 32 km W [24°55′17″N 111°58′5.5″W], O. Francke, W. Savary, A. Valdez and E. Gonzalez, 11.VII.2004, 26 m, UV light detection at night
Paruroctonus becki (Gertsch and Allred, 1965): 2 juv. ♀ (AMNH [LP 4991]), U.S.A.: California: Inyo County: Alabama Hills Recreational Area, 7 mi. W Lone Pine [36°35.991′N 118°11.005′W], L. Prendini and R. Mercurio, 5.IX.2005, collected with UV light
Paruroctonus boreus (Girard, 1854): 1 ♂ (AMNH [LP 4388]), U.S.A.: Washington: Yakima County: Humphrey Road, Tieton [46°41′15″N 120°46′25″W], H. Leochelt, 24.VIII.1996
Paruroctonus borregoensis borregoensis Williams, 1972: 1 ♀ (AMNH [LP 4530]), Mexico: Sonora: Municipio Puerto Peñasco: Reserva de la Biosfera and Parque Nacional El Pinacate: 95 km NW Sonoyta off Route 2, W of Microondas Cerro Lava [32°06.175′N 113°47.105′W], R. Mercurio and E. González, 28.VI.2005, collected with UV light at night
Paruroctonus gracilior (Hoffmann, 1931): 1 ♀ (AMNH [LP 2152]), U.S.A.: New Mexico: Eddy County: White's City, roadside 0.1 mi. S, K.J. McWest, 21.VI.2002; 1 ♀ (AMNH [LP 2213]), U.S.A.: Texas: Loving County: Wink, ca. 4 mi. NW at junction TX 302 and TX 1232 [31°48′55.08″N 103°12′11.43″W], WTAMU Arachnology Class, 5.X.2002
Paruroctonus stahnkei (Gertsch and Soleglad, 1966): 1 ♂ (AMNH [LP 3566]), U.S.A.: Arizona: Pima County: Tucson, near Bopp Road and Continental Road, B.R. Tomberlin and S.J. Burchfield, 15.IX.2004
Pseudouroctonus apacheanus (Gertsch and Soleglad, 1972): 1 ♀ (AMNH), U.S.A.: Arizona: Southwestern Research Station, 5 mi. W Portal, W.J. Gertsch, VII.1962
Pseudouroctonus reddelli (Gertsch and Soleglad, 1972): 1 ♀ (MNHN), U.S.A.: Texas: Travis County: Tooth Cave, Mitchell, 9.VI.1967; 1 ♀ (AMNH [LP 2155]), U.S.A.: Texas: Hays County: 0.5 mi. S Hays City, B. McMinn, 29.V.2002
Serradigitus wupatkiensis (Stahnke, 1940): 1 ♂ (AMNH [LP 3216]) U.S.A.: California: Inyo County: Inyo National Forest: White Mountains, roadside of 168 [37°15′45.0″N 118°09′19.1″W], W. Savary, R. Mercurio, K. Bamba and M. McCoy, 15.VIII.2004
Smeringurus vachoni vachoni (Stahnke, 1961): 1 ♂ (AMNH [LP 2684]), U.S.A.: California: San Bernardino County: Desert Studies Center, Soda Dry Lake, W.E. Savary and P.R. Craig, 5.VII.2003
Syntropis macrura Kraepelin, 1900: 1 juv. ♂ (AMNH [LP 4729]), Mexico: Baja California Sur: Municipio Comondú: San José de Comondú [26°03.542′N 111°48.985′W], L. Prendini, R. Mercurio, E. González, and W.E. Savary, 7.VI.2005, collected with UV light at night
Uroctonites huachuca (Gertsch and Soleglad, 1972): 1 ♀ (AMNH), U.S.A.: Arizona: Cochise County: Huachuca Mts, Cary Peak Trail, J. Burkhart, 20.IX.1969, 11:00 am, elev. 7000 ft, under rock slabs, deep pine needles
Uroctonus mordax mordax Thorell, 1876: 1 ♂ (AMNH [LP 1595]), U.S.A.: California: Contra Costa County: Clayton Road, near Clayton, W. Savary and L. Prendini, X.1997; 1 ♂ (ZMB 2392), U.S.A., California, Forrer; 2 ♀ (MNHN RS 0732), U.S.A.: California, M. Lourquin, 1953
Vaejovis intrepidus cristimanus Pocock, 1898: 1 ♂ (ZMB 15221), Mexico: San José, v. Blücher
Vaejovis magdalensis Williams, 1971: 1 ♀ (AMNH [LP 3155]), Mexico: Baja California Sur: La Paz, 50 km NW [24°5′56.2″N 110°43′41″W], O. Francke, E. González, and A. Valdez, 7.VII.2004, collected with UV light at night
Vaejovis mexicanus mexicanus C. L. Koch, 1836: 1 ♂ (AMNH [LP 1826]), Mexico: Estado de México: Municipio Atizapan de Zaragoza: Casa habitacion, O. Francke, X.2001
Vaejovis nitidulus C. L. Koch, 1843: 2 ♂ (AMNH [LP 2052]), Mexico: Hidalgo: Antena de Microondas de Zimapan [20°44′47″N 99°20′54″W], L. Prendini, O. Francke, E. Gonzalez, and J. Ponce, 3.VIII.2002, collected with UV light at night
Vaejovis spinigerus (Wood, 1863): 1 ♂ (AMNH [LP 1811]), U.S.A.: Arizona: Maricopa County: Buckeye Hills Recreation Area [33°17.039′N 112°38.754′W], J. and J. Bigelow, 24.VIII.2000
Vejovoidus longiunguis (Williams, 1969): 1 ♂ (AMNH [LP 3147]), Mexico: Baja California Sur: Guerrero Negro, 12 km S [27°56′5.8″N 113°54′23.1″W], O. Francke, W. Savary, E. González, and A. Valdez, 15.VI.2004, collected with UV light at night