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4 March 2010 On the Phylogenetic Placement of the Spider Genus Atimiosa Simon, 1895, and the Circumscription of Dolichognatha O.P.-Cambridge, 1869 (Tetragnathidae, Araneae)
Dimitar Dimitrov, Fernando Álvarez-Padilla, Gustavo Hormiga
Author Affiliations +
Abstract

The genus Atimiosa Simon, 1895, is a junior synonym of Dolichognatha O. P.-Cambridge, 1869. This synonymy is strongly supported by cladistic analyses of morphological characters and examination of types of all known Atimiosa species. Two new combinations resulted from this nomenclatural change, Dolichognatha comorensis (Schmidt and Krause, 1993), new combination, and Dolichognatha quinquemucronata (Simon, 1895), new combination. New illustrations and photographs of these two species and of the poorly known Dolichognatha longiceps (Thorell, 1895) are provided. We also describe for the first time the web architecture of D. longiceps.

INTRODUCTION

Tetragnathidae is a family of orbweaving spiders found worldwide; however, most of its species diversity is concentrated in the humid tropical regions of the world. More than 900 valid species of tetragnathids have been described, classified in 47 genera (Platnick, 2010). Many tetragnathid genera are associated with ecosystems neighboring freshwater bodies, such as lakes or rivers, where their population density is often very high, making them the dominating orbweavers in the habitat. Members of the family are also common in humid tropical forests where they are found from the ground level to the top of the canopy. As with many other tropical arthropods, most of the diversity is still undescribed. Inadequate descriptions and poor knowledge of many of the species further complicates any systematic work, hence the need for generic systematic revisions to address this problem. In recent years, several authors have addressed different aspects of tetragnathid systematics (e.g., Tanikawa, 2001; Gillespie, 2003a, 2003b; Álvarez-Padilla, 2007; Dimitrov et al., 2008; Smith, 2008; Dimitrov and Hormiga, 2009; Álvarez-Padilla et al., 2009), but due to the large size of the group many genera still require systematic revisions. The present paper is a continuation of our efforts to update tetragnathid systematics. It focuses on the South Asian genus Atimiosa 18Simon, 1895. We have examined the type specimens of the two known species of Atimiosa and studied their phylogenetic position within Tetragnathidae using morphological characters. The type species, Atimiosa quinquemucronata 18Simon, 1895, was originally described by 18Simon (1895) based on a subadult female specimen (fig. 1A–E) from Sri Lanka that is conspicuously similar to some Dolichognatha species. Schmidt and Krause (1993) subsequently described another species, Atimiosa comorensis Schmidt and Krause, 1993, from the Comoro Islands. It is in fact puzzling how Schmidt and Krause (1993) may have decided on this generic placement given that Simon's description mentions very few diagnostic traits, all of them consistent with Dolichognatha. A rationale for the generic placement is absent from Schmidt and Krause's paper. In this paper we propose the synonymization of the genus Atimiosa with Dolichognatha based on the examination of the type specimens of both species and on the results of cladistic analyses that include all known Atimiosa species and a broad sample of tetragnathids. Recent treatments of Dolichognatha and several small and poorly known tetragnathid genera from Australasia and Africa have produced six generic synonymies for Dolichognatha (Levi, 1981; Smith, 2008). In addition, they have also provided illustrated descriptions of several Dolichognatha species. We extend these efforts to facilitate identification and future taxonomic work by providing illustrations and photographs of all species formerly included in Atimiosa. Specimens of the poorly known species Dolichognatha longiceps (Thorell, 1895) are also illustrated and included in the analyses to better test the monophyly of the genus; that species was also selected because of its unusual morphological features, such as the absence of PME. Here we provide additional illustrations of D. longiceps and document for the first time its web architecture.

Fig. 1

Dolichognatha quinquemucronata (18Simon, 1895), new combination. Subadult female holotype from Sri Lanka (MNHM 16140): ventral (A), dorsal (B). Cephalothorax: dorsal (C), frontal (D). Abdomen and genital area, ventral (E).

i0003-0082-3683-1-1-f01.tif

MATERIALS AND METHODS

Type specimens for this study were borrowed from the museum collections listed at the end of this section. Specimens from Dolichognatha longiceps were collected by GH in Thailand. Digital photographs of the type in the Muséum National d'Histoire Naturelle, Paris (MNHN) were taken by FAP with a Nikon Coolpix 995 camera while visiting the collections. The morphological methods of our study follow those previously described in Hormiga (2002). Other specimens were examined and illustrated using Leica MZ16 or Leica MZ16A stereoscopic microscopes with a camera lucida and Leica DMRM compound microscope with a drawing tube. Drawings were prepared with graphite pencils on acid-free cotton paper. Hairs and macrosetae are not depicted in the final drawings. For male palp illustrations the left palp was used. Epigyna were treated with SIGMA Pancreatin LP 1750 enzyme complex (Álvarez-Padilla and Hormiga, 2008) and transferred to methyl salicylate solution for examination and illustration.

All pencil drawings were scanned and further improved with the help of the Gimp 2.4 and Adobe Photoshop CS2 programs. Digital images of the specimens were taken in alcohol with Nikon DXM1200F digital camera mounted on a Leica MZ16A stereoscopic microscope. Final plate layout and editing was done with Adobe Illustrator CS2. All measurements are in millimeters.

Abbreviations Used in Text and Figures

ALE

anterior lateral eyes

C

conductor

CB

cymbium

CEBP

cymbial ecto-basal process

CD

copulatory duct

E

embolus

FD

fertilization duct

MEA

metine embolic apophysis

MPT

maximum parsimony tree

P

paracymbium

PLE

posterior lateral eyes

PME

posterior median eyes

S

spermatheca

ST

subtegulum

T

tegulum

Museum Collections

AMNH

American Museum of Natural History, New York, USA

MCZ

Museum of Comparative Zoology, Cambridge, USA

MNHN

Muséum National d'Histoire Naturelle, Paris, France

NRM

Naturhistoriska riksmuseet, Stockholm, Sweden

RMCA

Musée royal de l'Afrique centrale, Tervuren, Belgium

PHYLOGENETICS

Morphological characters for Atimiosa comorensis, A. quinquemucronata, Dolichognatha incaensis (18Simon, 1895), D. longiceps, and Cyrtognatha insolita (Chickering, 1956) were scored (Appendix 1) and added to the morphological matrix of Álvarez-Padilla et al. (2009). That work (Álvarez-Padilla et al., 2009) provides the largest and most complete morphological data matrix for Tetragnathidae to date, along with a large number of outgroup representatives. This relatively extensive taxon sample, coupled with the large number of characters (213 morphological and behavioral characters), allows robust testing of phylogenetic hypotheses for the relationships of tetragnathid genera. Here we use that dataset to test the phylogenetic position of the tetragnathid genus Atimiosa. We retain the original taxon sample of Álvarez-Padilla et al. (2009) and add to the matrix the taxa listed above and in Appendix 1.

Very few characters were scored for A. quinquemucronata because the only specimen available for study was the subadult type. Nonetheless, we have added this species to the matrix because it is the type species of the genus Atimiosa. Several somatic characters reflecting traits such as eye size and distribution, which do not show sexual dimorphism, were scored from the male type of A. comorensis. Dolichognatha incaensis specimens were not directly examined, but we used available information (SEM images, drawings, descriptions, and character scores) from the literature (Smith, 2008). The type species of Dolichognatha, D. nietneri O. P.-Cambridge, 1869, was not included in the analyses. This species is known from just a single male specimen lodged in the Natural History Museum (London). The original description of D. nietneri provides very detailed information on the somatic morphology of this species (O. P.-Cambridge, 1869). The type specimen was also examined by Levi (1981), who confirmed O.P.-Cambridge's observations. Based on these data we can confirm that D. longiceps and D. incaensis are congeneric with D. nietneri and that all of them share the same putative synapomorphies of the genus. The monophyly of Dolichognatha is not questioned, and thus, unlike in the case of Atimiosa whose type species is a subadult specimen with unclear affinities, we did not include D. nietneri in the analyses. Instead, we scored two other species (D. longiceps and D. incaensis) for which we have detailed information of male and female morphology and behavior (in the case of D. longiceps). Dolichognatha pentagona (Hentz, 1850) is the only other Dolichognatha species for which detailed morphological and behavioral information is available and it was already included in the matrix of Álvarez-Padilla et al. (2009). We have also added the species C. insolita to the analyses to better represent the morphological variability of Cyrtognatha (see appendix 1). The character scores of C. insolita are based on direct examination of the holotype (male from Panama, Barro Colorado Island, in MCZ 21668) in addition to the SEM images, drawings, and descriptions provided by Dimitrov and Hormiga (2009). One characteristic of C. insolita, the presence of a “metine embolic apophysis” (MEA), is particularly relevant as most of the species of Cyrtognatha have this apophysis (Dimitrov and Hormiga, 2009), which is absent in C. espanola (Bryant, 1945). The latter species was used in the phylogenetic analyses of Álvarez-Padilla et al. (2009). Dolichognatha has an MEA and the proper representation of the dominant embolic morphology in Cyrtognatha is important for the correct optimization of this character. To reflect recent observations we have also changed two scores for Pachygnatha autumnalis Marx, 1884 as follows: character 154 (female abdominal dorsal surface) from 0 to 1 and character 183 (male palpal trochanter length) from 0 to 1. Character descriptions are discussed elsewhere (Dimitrov and Hormiga, 2009; Álvarez-Padilla et al., 2009). Character numbers and character definitions are as in Álvarez-Padilla et al. (2009).

Matrix editing and manipulation was performed in Mesquite version 2.0 (build i69) (Maddison and Maddison, 2008). Parsimony analyses under equal and implied weights were performed in TNT version 1.1 (Goloboff et al., 2003). Cladistic analyses were performed following the methodology of Dimitrov and Hormiga (2009).

RESULTS FROM THE CLADISTIC ANALYSES

Analysis of the complete data matrix under equal weights found six minimal length trees 1045 steps long (CI  =  0.26, RI  =  0.60). The strict consensus of these trees is shown in figure 9 (L  =  1059, CI  =  0.25, RI  =  0.60). Atimiosa comorensis is nested in a clade together with the Dolichognatha species and A. quinquemucronata, but this clade is not well supported by resampling indices and Bremer support. The sister group of Dolichognatha is the genus Metellina Chamberlin and Ivie, 1941. Dolichognatha together with Meta C.L. Koch, 1836, and Metellina form a monophyletic group but it does not receive support form the resampling indices and Bremer support is low (Bremer support  =  1). When missing data are reduced by excluding A. quinquemucronata (92.5% missing data) from the analyses, the same six trees are found, but they are one step shorter (L  =  1044, CI  =  0.26, RI  =  0.60). Their strict consensus is shown in figure 10 (L  =  1058, CI  =  0.25, RI  =  0.60). The topology of these trees is exactly the same as when A. quinquemucronata is included in the analyses with one difference: the clade that includes the species of Dolichognatha and A. comorensis receives very high support from the resampling indices and has the highest Bremer support (12).

Analyses under implied weights always recover a monophyletic group that includes Dolichognatha, Meta, and Metellina. The topology of this group is the same as under equal weights when k ≥5. At k values lower than 5 Dolichognatha (including Atimiosa) is paraphyletic with respect to Meta and Metellina. The same results are obtained when A. quinquemucronata is excluded from the analyses (Fig. 11.Continued.fig. 11).

Three additional monophyletic groups that receive support and are stable under different analytical treatments can be distinguished within Tetragnathidae: Leucauginae, Tetragnathinae, and the Australian lineage known as “Nanometa clade” (see Álvarez-Padilla, 2007; Dimitrov and Hormiga, 2009; Álvarez-Padilla et al., 2009). The phylogenetic placement of the genera Azilia Keyserling, 1881, Mollemeta Álvarez-Padilla, 2007, Chrysometa Simon, 1894, and Allende Álvarez-Padilla, 2007, however, is very unstable and varies with values of k. Alternative topologies under different k values when missing data are reduced (A. quinquemucronata excluded from the analyses) are shown in Fig. 11.Continued.figure 11.

Tetragnathidae is recovered as monophyletic in all analyses, but it does not receive support from any of the resampling indices. However, tetragnathids are well supported by the Bremer support (5) when missing data are reduced (fig. 10).

DISCUSSION

Our results show that if treated as a separate genus, Atimiosa would render Dolichognatha paraphyletic. If Atimiosa comorensis were to be transferred to the genus Dolichognatha, Atimiosa would be rendered monotypic and sister to Dolichognatha, which we view as undesirable. Detailed examination of the morphology of Atimiosa quinquemucronata shows that it has all diagnostic characters of Dolichognatha (e.g., see Levi, 1981). Treating Atimiosa as a junior synonym of Dolichognatha is the soundest alternative.

Results from different analytical treatments always recovered a Metainae lineage including Dolichognatha, Meta and Metellina. For further discussion on higher-level tetragnathid relationships, see recent phylogenetic treatments in Álvarez-Padilla (2007), Dimitrov and Hormiga (2009), and Álvarez-Padilla et al. (2009).

A very interesting feature of D. longiceps that deserves comment is the strong reduction of the PME. As far as we know this is the only case in tetragnathids where complete eye reduction (loss) has taken place. Cases of eye reduction are common in cave-dwelling spiders and there are many Meta species known to exhibit cavernicolous tendencies. All known species of Meta, however, have eight eyes. Interestingly D. longiceps does not live in caves but in humid Southeast Asian tropical forests where it builds its webs near the ground between the roots and buttresses of trees (fig. 8). Variation in the size of the PME across Dolichognatha species suggests a possible process of eye reduction in this genus. The evolutionary forces driving this process and its biological significance remain unknown.

TAXONOMY

  • Dolichognatha O. P.-Cambridge, 1869

  • Type species

    Dolichognatha nietneri O. P.-Cambridge, 1869.

  • Landana Simon, 1884, transferred from Archaeidae to Araneidae by Lehtinen, 1967: 289, here by Levi, 1981: 277.

  • Paraebius Thorell, 1894, Prolochus Thorell, 1895, Nicholasia Bryant and Archer, 1940, type Araneus pentagonus (Hentz, 1850) and Afiamalu Marples, 1955, type Afiamalu richardi Marples, 1955, transferred here by Levi, 1981: 277.

  • Homalopoltys 18Simon, 1895, transferred here by Smith, 2008: 10.

  • Atimiosa 18Simon, 1895, new synonymy, type species Atimiosa quinquemucronata 18Simon, 1895.

  • Justification for the synonymy

    The holotype of Atimiosa quinquemucronata is a subadult female. Describing new taxa based on juvenile specimens was common before the early 20th century. The validity of taxa based on such specimens is often difficult to assess because genital morphology cannot be examined and they are subsequently neglected or treated as nomina dubia. Fortunately, A. quinquemucronata shares some easily recognizable somatic features with the genus Dolichognatha, such as the separated lateral eyes, PME smaller than the lateral eyes, and the absence of fourth femur trichobothria in females. The size and distribution of the eyes are particularly relevant, as those are among the most important diagnostic characters of Dolichognatha. The pointed tip of the abdomen and the shape of the labium and sternum are also as in Dolichognatha. Based on these observations and the results from our cladistic analyses (figs. 9; 10), we transfer all Atimiosa species to Dolichognatha, which renders the former genus into a junior synonym of Dolichognatha.

    Diagnosis

    The genus Dolichognatha can be most easily distinguished from close relatives (Meta and Metellina) by the very long male chelicerae and the characteristic shape and coloration of the prosoma. In Dolichognatha the cephalic region is rectangular in shape and elongated with dark sides (e.g., fig. 6A). In addition, the following combination of characters differentiates Dolichognatha from other tetragnathids: aggregate spigots not embracing the flagelliform spigot, PME and PLE without canoe tapetum, PME smaller than PLE, abdomen with anterior tubercles, and horizontal orb web with closed web hub close to the substrate.

    Phylogenetics

    The monophyly of Dolichognatha is supported by all analyses and it is placed in a Metainae lineage together with the genera Meta and Metellina (figs. 9; 10), which includes also Mollemeta, Chrysometa, and Allende when k  =  4–7 (Fig. 11.Continued.fig. 11). All analyses, except when k ≤ 3, found Dolichognatha sister to Metellina. Three unambiguous synapomorphies support the monophyly of Dolichognatha (fig. 12A): PLE larger than PME, lateral eyes separated, and anterior abdominal tubercles present. When A. quinquemucronata is excluded form the analyses the number of synapomorphies supporting Dolichognatha increases to 17 (fig. 12B) due to the reduction of data missing from the matrix. These synapomorphies include: aggregate spigots not embracing the flagelliform spigot; apically distended conductor path; short clypeus; PME close to each other (less than one PME diameter); PME without canoe tapetum; PLE without canoe tapetum; PME smaller than PLE; lateral eyes separated; male paturon with a basal tubercle; male chelicerae larger than in female; intermediate length of copulatory ducts; short fertilization ducts; abdomen with anterior tubercles; male palpal patella without macrosetae; horizontal orb web; and closed web hub.

    Composition

    Dolichognatha comprises 29 described species (Platnick, 2010), including the two new combinations proposed here: D. aethiopica Tullgren, 1910; D. albida (18Simon, 1895); D. baforti (Legendre, 1967); D. cygnea (Simon, 1893); D. deelemanae Smith, 2008; D. ducke Lise, 1993; D. erwini Brescovit and Cunha, 2001; D. incanescens; D. kampa Brescovit and Cunha, 2001; D. kratochvili (Lessert, 1938); D. lodiculafaciens (Hingston, 1932); D. longiceps; D. mandibularis (Thorell, 1894); D. mapia Brescovit and Cunha, 2001; D. maturaca Lise, 1993; D. minuscula (Mello-Leitão, 1940); D. nietneri; D. pentagona; D. petiti (Simon, 1884); D. pinheiral Brescovit and Cunha, 2001; D. proserpina (Mello-Leitão, 1943); D. quadrituberculata (Keyserling, 1883); D. raveni Smith, 2008; D. richardi (Marples, 1955); D. spinosa (Petrunkevitch, 1939); D. tigrina Simon, 1893; D. umbrophila Tanikawa, 1991; D. quinquemucronata (18Simon, 1895), new combination; and D. comorensis (Schmidt and Krause, 1993), new combination.

    Distribution

    Dolichognatha has a circumtropical distribution with the highest species diversity in South America and Southeast Asia.

    Natural History

    The majority of Dolichognatha species live near the ground where they build nearly horizontal orb webs (Levi, 1981; Smith, 2008 and observations reported herein). However, there are at lest some species, such as D. albida, that were reported to build vertical orb webs (Simon, 1894). Smith (2008) confirms that Dolichognatha species may live in the canopy, as specimens for her study were collected using canopy-fogging techniques. Unfortunately, she did not observe the webs of these specimens. Our observations of D. longiceps webs are consistent with the descriptions of Levi (1981) and represent the most common web architecture in Dolichognatha (horizontal orbs close to the substrate).

  • Dolichognatha quinquemucronata (18Simon, 1895), new combination

  • Figures 1A–E

  • Atimiosa quinquemucronata Simon, 1894: 742 (nomen nudum).

  • Atimiosa quinquemucronata Simon, 1895a: 154.

  • Type

    Subadult female holotype from Sri Lanka. The only information on the label, other than the collection number and the species name, is “Nuw. El.” (MNHN 16140, examined).

    Justification of the Transfer

    The type specimen, which is also the only known specimen of this species, is a subadult female (fig. 1A, E), thus it is impossible to study its genital morphology. However, it has all somatic characters diagnostic of Dolichognatha, such as: PME smaller than the PLE, PLE, and ALE separated, chelicerae slender and elongated, and femur IV without trichobothria. Even with 92.5% missing data in the data matrix, the cladistic analyses unambiguously placed this species in a group together with the Dolichognatha species included in our analyses and with A. comorensis. Based on this cladistic hypothesis (fig. 9), we transfer A. quinquemucronata to the genus Dolichognatha.

    Comments

    There are three other species of Dolichognatha besides D. quinquemucronata described from Sri Lanka: D. incanescens, D. nietneri, and D. albida. This makes a reconciliation of the subadult specimen of D. quinquemucronata a very difficult task. However, the presence of characteristic abdominal tubercles in D. quinquemucronata, which differ from those of the other three Sri Lankan species, and its eye pattern, may prove useful if adults with these traits are collected. At present, as the holotype of D. quinquemucronata is a subadult specimen that cannot be identified, we suggest that it should be treated as nomen nudum.

  • Dolichognatha comorensis (Schmidt and Krause, 1993), new combination

  • Figures 2A–E; 3A–C

  • Fig. 2

    Dolichognatha comorensis (Schmidt and Krause, 1993), new combination. Male palp: prolateral (A), retrolateral (B), ventral (C), schematic (ventral) (D). Habitus: dorsal (E).

    i0003-0082-3683-1-1-f02.tif

    Fig. 3

    Dolichognatha comorensis (Schmidt and Krause, 1993), new combination holotype from Grande Comoro (RMCA 160.649). Male: ventral (A), lateral (B), frontal (C).

    i0003-0082-3683-1-1-f03.tif

    Type

    Holotype male from Comoros Islands, Grande Comoro, Boboni, 27.xi.1983, elevation 600m, R. Jocqué leg. (RMCA 160.649, examined).

    Justification for the Transfer

    Morphology of the male palp of this species (presence of CBEP and metine embolic apophysis; shape of conductor and embolus) as well as eye size and arrangement are consistent with placement in the genus Dolichognatha. Transfer is further supported by the results from our cladistic analyses: parsimony analyses under equal and implied weights always, except when k ≤ 3, found A. comorensis nested within Dolichognatha (figs. 9, 10).

  • Dolichognatha longiceps (Thorell, 1895)

  • Figures 4A–F; 5A–D; 6A–D; 7; 8

  • Prolochus longiceps Thorell, 1895: 122; Simon, 1895b: 932, 1004.

  • Fig. 4

    Dolichognatha longiceps (Thorell, 1895) from Thailand (specimen in AMNH). Male palp: ventral (A), retroalteral (B), prolateral (C), schematic (ventral) (D). Dolichognatha longiceps (Thorell, 1895) from Thailand (specimen in AMNH). Epigynum: dorsal (E), ventral (F).

    i0003-0082-3683-1-1-f04.tif

    Fig. 5

    Dolichognatha longiceps (Thorell, 1895) from Thailand (specimen in AMNH). Male: dorsal (A), frontal (B), lateral (C), ventral (D).

    i0003-0082-3683-1-1-f05.tif

    Fig. 6

    Dolichognatha longiceps (Thorell, 1895) from Thailand (specimen in AMNH). Female: dorsal (A), frontal (B), lateral (C), ventral (D).

    i0003-0082-3683-1-1-f06.tif

    Fig. 7

    Dolichognatha longiceps (Thorell, 1895) from Thailand (specimen in AMNH), epigynum.

    i0003-0082-3683-1-1-f07.tif

    Fig. 8

    Dolichognatha longiceps (Thorell, 1895) from Thailand. Web architecture (web about 40 cm wide; photo F. Álvarez-Padilla) (A), hub (photo F. Álvarez-Padilla) (B).

    i0003-0082-3683-1-1-f08.tif

    Fig. 9

    Strict consensus of the six MPTs found by TNT under the equal weights parsimony criterion analyzing the complete data set (L  =  1059, CI  =  0.25, RI  =  0.60). Numbers cutting the branches represent Bremer support; over the branches, standard bootstrap/jackknife; below the branches, Poisson bootstrap/symmetric resampling. Dolichognatha is shown in a gray box.

    i0003-0082-3683-1-1-f09.tif

    Fig. 10

    Strict consensus of the six MPTs found by TNT under the equal weights parsimony criterion analyzing the matrix without A. quinquemucronata (L  =  1058, CI  =  0.25, RI  =  0.60). Numbers cutting the branches represent Bremer support; over the branches, standard bootstrap/jackknife; below the branches, Poisson bootstrap/symmetric resampling. Dolichognatha is shown in a gray box.

    i0003-0082-3683-1-1-f10.tif

    Fig. 11

    Alternative topologies (above and at right, on opposite page) obtained analyzing the data under the implied weighting criterion using different values of the concavity constant k (A. quinquemucronata not included in the analyses).

    i0003-0082-3683-1-1-f11p1.tif

    Fig. 11.Continued.

    i0003-0082-3683-1-1-f11p2.tif

    Fig. 12

    Unambiguous synapomorphies of Dolichognatha and sister taxa mapped over the consensus tree from analyses of the complete matrix (A) and when A. quinquemucronata is not included in the analyses (B). All changes in the Metainae lineage depicted in this figure are homoplasious, thus marked with white circles.

    i0003-0082-3683-1-1-f12.tif

    Types

    Syntypes of Dolichognatha longiceps are deposited in NRM. We did not directly examine the type specimens ourselves. However, to ensure correct determination we have compared our specimens to a digital photograph of the male holotype that was kindly made available by Torbjörn Kronestedt and Gunvi Lindberg, and to the drawings available in the literature.

    Description of the Web

    Dolichognatha longiceps spins its orb web near the ground at the base of trees. The web that we observed was built between the buttresses of a tree. It is two-dimensional with oval shape (fig. 8A) and with a major axis of 40 cm. The web orientation is horizontal with dense spiral turns and numerous radii, without split radii (fig. 8). The web frame is an irregular polygonal shape and has numerous attachment sites (fig. 8A). The hub is closed (fig. 8B) and seems somewhat displaced toward one of the edges.

    Additional Material Examined

    One male and two females from Thale Ban National Park, Satun Province, THAILAND. N6°42′37.0″, E100°10′09.2″, elev. 270m, 15–18.x.2003, G. Hormiga leg. In AMNH.

    Acknowledgments

    We thank Mark Harvey and an anonymous reviewer for their comments on the manuscript. For the loan of specimens we would like to thank Rudy Jocqué, Musée royal de l'Afrique centrale (Tervuren) and Gonzalo Giribet, Museum of Comparative Zoology (Cambridge). We thank Torbjörn Kronestedt and Gunvi Lindberg, Naturhistoriska riksmuseet (Stockholm) for providing digital images of the type of D. longiceps. We also thank Christine Rollard, Musée National d'Histoire Naturelle (Paris) for access to the collections. For help with the fieldwork in Thailand we would like to acknowledge C. Hutacharern, N. Scharff, M. Ramírez, J. Birkedal, J. Coddington, D. de Roche, and P. Wongprom.

    Funding for this research has been provided by a PEET grant from the U.S. National Science Foundation (DEB-0328644 to G. Hormiga and G. Giribet) and by Research Enhancement Fund and Selective Excellence grants from the George Washington University. Fieldwork in Thailand was funded by an ATOL grant from the U.S. National Science Foundation (EAR-0228699) to W. Wheeler, J. Coddington, G. Hormiga, L. Prendini, and P. Sierwald.

    REFERENCES

    1.

    F. Álvarez-Padilla 2007. Taxonomic revision of the spider genus Metabus (Araneae: Tetragnathidae) with comments on the tetragnathid fauna of Chile and the phylogeny of Tetragnathidae. Zoological Journal of the Linnaean Society 151:285–335. Google Scholar

    2.

    F. Álvarez-Padilla, D. Dimitrov, G. Giribet, and G. Hormiga . 2009. Phylogenetic relationships of the spider family Tetragnathidae (Araneae, Araneoidea) based on morphological and DNA sequence data. Cladistics 25:109–146. Google Scholar

    3.

    F. Álvarez–Padilla and G. Hormiga . 2008. A protocol for digesting internal soft tissues and mounting spiders for scanning electron microscopy. Journal of Arachnology 35:538–542. Google Scholar

    4.

    O. P- Cambridge 1869. Catalogue of a collection of Ceylon Araneida lately received from Mr J. Nietner, with descriptions of new species and characters of a new genus. I. Journal of the Linnean Society London (Zoology) 10:373–397. Google Scholar

    5.

    D. Dimitrov, F. Álvarez-Padilla, and G. Hormiga . 2008. Until dirt do us apart: on the unremarkable palp morphology of the spider Sternospina concretipalpis Schmidt & Krause, 1993, with comments on the genus Prionolaema Simon, 1894 (Araneae, Tetragnathidae). Zootaxa 1698:49–56. Google Scholar

    6.

    D. Dimitrov and G. Hormiga . 2009. Revision and cladistic analysis of the orbweaving spider genus Cyrtognatha Keyserling, 1881 (Araneae, Tetragnathidae). Bulletin of the American Museum of Natural History 317:1–140. Google Scholar

    7.

    R. G. Gillespie 2003a. Marquesan spiders of the genus Tetragnatha. Journal of Arachnology 31:62–77. Google Scholar

    8.

    R. G. Gillespie 2003b. Spiders of the genus Tetragnatha in the Society Islands. Journal of Arachnology 31:157–172. Google Scholar

    9.

    P. Goloboff, J. Farris, and K. Nixon . 2003. T.N.T.: Tree analyses using new technology. (Program and documentation available from the authors and at  www.zmuc.dk/public/phylogeny).  Google Scholar

    10.

    G. Hormiga 2002. Orsonwelles, a new genus of giant linyphiid spiders (Araneae) from the Hawaiian Islands. Invertebrate Systematics 16:369–448. Google Scholar

    11.

    P. T. Lehtinen 1967. Classification of the cribellate spiders and some allied families, with notes on the evolution of the suborder Araneomorpha. Annales Zoologici Fennici 4:199–468. Google Scholar

    12.

    H. W. Levi 1981. The American orb-weaver genera Dolichognatha and Tetragnatha north of Mexico (Araneae: Araneidae, Tetragnathinae). Bulletin of the Museum of Comparative Zoology Harvard 149:271–318. Google Scholar

    13.

    W. P. Maddison and D. R. Maddison . 2008. Mesquite: a modular system for evolutionary analysis. Version 2.0. ( http://mesquiteproject.org).  Google Scholar

    14.

    N. I. Platnick 2010. The world spider catalog, version 10.5. American Museum of Natural History (online at  http://research.amnh.org/entomology/spiders/catalog/index.html).  Google Scholar

    15.

    G. Schmidt and R. H. Krause . 1993. Spinnen von den Komoren III: Tetragnathinae und Metinae (Araneida: Araneidae). Teil I. Arachnologisches Magazin 1 10:4–9. Google Scholar

    16.

    G. Schmidt and R. H. Krause . 1994. Spinnen von den Komoren 3: Tetragnathinae und Metinae (Araneida: Araneidae). Arachnologisches Magazin 2 Sonderausgabe 1:3–25 [reprint of Schmidt and Krause, 1993]. Google Scholar

    17.

    E. Simon 1894. Histoire naturelle des araignées. 1:489–760. Paris Roret. Google Scholar

    18.

    E. Simon 1895a. Etudes arachnologiques. 26e. XLI. Descriptions d'espèces et de genres nouveaux de l'ordre des Araneae. Annales de la Société Entomologique de France 64:131–160. Google Scholar

    19.

    E. Simon 1895b. Histoire naturelle des araignées. 2:761–1084. Paris Roret. Google Scholar

    20.

    H. M. Smith 2008. Synonymy of Homalopoltys (Araneae: Araneidae) with the genus Dolichognatha (Araneae: Tetragnathidae) and descriptions of two new species. Zootaxa 1775:1–24. Google Scholar

    21.

    A. Tanikawa 2001. Okileucauge sasakii, a new genus and species of spider from Okinawajima Island, southwest Japan (Araneae, Tetragnathidae). Journal of Arachnology 29:16–20. Google Scholar

    22.

    T. Thorell 1895. Descriptive catalogue of the spiders of Burma. London British Museum. 406. Google Scholar

    Appendices

    APPENDIX 1

    Matrix for cladistic analyses Characters are numbered as in Álvarez-Padilla et al. (2009). Character descriptions and scores for the remaining taxa are discussed and published in Álvarez-Padilla et al. (2009).

    i0003-0082-3683-1-1-ta01.tif

    Dimitar Dimitrov, Fernando Álvarez-Padilla, and Gustavo Hormiga "On the Phylogenetic Placement of the Spider Genus Atimiosa Simon, 1895, and the Circumscription of Dolichognatha O.P.-Cambridge, 1869 (Tetragnathidae, Araneae)," American Museum Novitates 2010(3683), 1-19, (4 March 2010). https://doi.org/10.1206/669.1
    Published: 4 March 2010
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