A recent definition of Asterorhombus is composed of only two characters: lack of sexual dimorphism; deep clefts in caudal bones (parhypural, hypurals, epurals). The genus currently contains seven nominal species: A. annulatus, A. bleekeri, A. osculus, A. cocosensis, A. fijiensis, A. intermedius, and A. filifer. Herein the genus is redefined, and as a result, A. annulatus, A. bleekeri, and A. osculus are transferred to Engyprosopon; Asterorhombus is reduced to four nominal species, A. cocosensis, A. fijiensis, A. intermedius, and A. filifer. Asterorhombus fijiensis is shown to be a junior synonym of A. cocosensis. Asterorhombus filifer and A. cocosensis are confirmed to have sexual dimorphism in interorbital width. Species of Asterorhombus were found to show two patterns of distribution: A. intermedius and A. cocosensis, Indo-West Pacific–distributed from the Indian Ocean to the western Pacific, not occurring nonmarginally on the Pacific Plate; A. filifer, Indo-Pacific–distributed from the Indian Ocean to nonmarginal localities on the Pacific Plate.

We describe two new species of salamanders of the genus Pseudoeurycea from mountains in the northern part of the state of Oaxaca, Mexico. Pseudoeurycea papenfussi, a large, muscular member of the P. gadovii group, occurs near the peaks (just below 3000 m) of the highest mountains of the Sierra de Juárez. It is related to P. smithi, a more southerly species, and possibly to P. aquatica, another species from Oaxaca. Pseudoeurycea obesa, a rotund member of the P. leprosa group, is known only from the type locality in the Sierra Mazateca at the northernmost extremity of Oaxaca. It is related to P. werleri and P. mystax, which are known from more southern parts of Oaxaca. These descriptions bring to 27 the number of species of salamanders known from Oaxaca. Most of these species are endemic to the state and are known only from regions that are undergoing rapid habitat modification and destruction.

A new species of Etropus, E. ciadi, is described, and it is characterized by the following combination of characters: small size (maximum 92.7 mm SL); body depth generally more than 50% SL (47.1–60.6%, only 1.6% of 243 specimens less than 50%); head relatively small (22.1–26.6% SL); deciduous scales without small accessory scales on exposed surface; teeth feeble and mobile; 66–79 and 52–62 dorsal-and anal-fin rays, respectively; 36–43 lateral-line scales; pelvic-fin rays nearly always 6; gill rakers 2–7 5–10 on first arch; dark brown speckles on body and dorsal-and anal-fin rays. Of its eastern Pacific congeners, E. ciadi is most similar to E. crossotus. Etropus ciadi is endemic to the Gulf of California and lives on soft bottoms in shallow depths (8–40 m), from Rocas Consag, Baja California, (31°18.2′ N, 114°25.0′ W) to Bahía Altata, Sinaloa (ca. 24°36′ N, 107°55′ W).

Three new species of Phrynopus (Anura: Leptodactylidae) are described from cloud forest and puna habitats in central Peruvian Departamento de Pasco between 3600 and 4390 m elevation, the latter is the highest known elevation of the genus. The new species have first finger shorter than second, vomerine teeth absent, and tympanic membrane and tympanic annulus absent, but differ in snout-vent length, skin texture, and coloration. Currently 37 species of Phrynopus are described, 26 (70.3%) of which are endemic to Peru.

Brachyplatystoma capapretum n. sp., a pimelodid catfish from the Amazon River, is described and diagnosed by its fine, densely spaced outer jaw teeth and relatively few rows of straight, depressible inner teeth; juveniles with large dark blotches on and above lateral line; adults with exceptionally dark pigmentation dorsally, abruptly countershaded near lateral line; broad, shallowly forked caudal fin. The systematic position of the new species was investigated with a maximum parsimony phylogenetic analysis of morphological characters. The resulting cladograms identify a nested set of unambiguous characters supporting the following monophyletic groups and taxonomic recommendations. Brachyplatystomatini new tribe is established for Brachyplatystoma and Platynematichthys and supported by two synapormorphies: two-chambered gas bladder connected by paired lateral tubes; cleithrum with blade-like ventral crest between pectoral spine articulation and posterior process of cleithrum. The monotypic genera Goslinia and Merodontotus are placed in synonymy with Brachyplatystoma characterized here by two synapomorphies: suspensorium greatly expanded mediodorsally, forming a massive plate approaching parasphenoid; juveniles with greatly elongated caudal-fin filaments developed from single outermost, unbranched principal rays. Bleeker's genus group name Malacobagrus is employed as a subgenus within Brachyplatystoma to include B. filamentosum, B. capapretum, and B. rousseauxii. Monophyly of Malacobagrus is supported by five synapomorphies: adults developing extensive reticulated system of lateralis tubules on body; Weberian complex with thick, ventral bony platform at gas bladder attachment; subquadrangular shape of opercle; pectoral spine with sulcus along anterior edge; small, non-sutured endopterygoid. Two unique synapomorphies place B. capapretum and B. filamentosum together as sister species: juveniles with spots on and above lateral line; caudal peduncle subcircular in cross-section.

The comparative diet and body size of the Four-Lined Snake (Elaphe quatuorlineata), one of the largest and more vulnerable species of snakes in Mediterranean central Italy, were studied in five different habitats. Data given here collated both literature and original data. Overall, females were significantly larger than males but the strength of these differences varied considerably with sample size. Overall, small mammals (almost exclusively rodents) accounted for the main part of the diet (66.7%), followed by birds and their eggs (mainly Passeriformes; 26.4%), and by lizards (6.9%), although the number of eggs in the diet was probably greatly underestimated. In qualitative terms, both sexes fed on the same prey types, but, quantitatively, males and females differed significantly in terms of prey composition; females fed on more birds and fewer lizards than males. Rodents were the most important prey source in most habitat types, although birds were preyed upon slightly more frequently in the wet habitat than rodents, which, nonetheless, still represented a important prey source. Four-Lined Snakes started feeding in early April and continued feeding until early November. The monthly frequency of occurrence of birds in snake stomachs differed significantly from that of small mammals; birds were taken almost exclusively in April and May (and mainly by females), and small mammals were taken all throughout the annual feeding cycle of snakes.

A small collection of anurans from the Cordillera Yanachaga in central Peru revealed the presence of 10 species of Eleutherodactylus. Four of these species are unknown elsewhere and are described herein. Three of the new species are members of the immense Eleutherodactylus unistrigatus group, and one belongs with the smaller, South American Eleutherodactylus conspicillatus group. The 83 described species of Eleutherodactylus known in Peru belong to six species groups that have different patterns of distribution. Most species in the cloud forest in the Cordillera Oriental, Cordillera Central, and associated ranges have small latitudinal and elevational distributions.

We studied spatiotemporal patterns of fish assemblage structure in the Neosho River, Kansas, a system impounded by low-head dams. Spatial variation in the fish assemblage was related to the location of dams that created alternating lotic and lentic stream reaches with differing fish assemblages. At upstream sites close to dams, assemblages were characterized by species associated with deeper, slower-flowing habitat. Assemblages at sites immediately downstream from dams had higher abundance of species common to shallow, swift-flowing habitat. Temporal variation in assemblage structure was stronger than spatial variation, and was associated with fish life history events such as spawning and recruitment, as well as seasonal changes in environmental conditions. Our results suggest that low-head dams can influence spatial patterns of fish assemblage structure in systems such as the Neosho River and that such assemblages also vary seasonally.

A new species of Pareiorhina is described from the Ribeirão Grande and adjacent drainages, in the left bank of the Rio Paraíba do Sul basin, in São Paulo State, southeastern Brazil. Pareiorhina brachyrhyncha is uniquely diagnosed among its congeners by the reduction or absence of azygous plates in front of the nuchal plate. It also differs from its congeners by the presence of a minute lateral cusp in the teeth, wider body, anterior and lateral profile of head rounded, broad distal profile of the paired fins, and lower number of vertebrae. The species is considered to be closely related to the sympatric P. rudolphi, based on the lack of azygous dorsal plates above the caudal peduncle.

Sturisoma kneri is a mailed catfish, endemic to the Lago Maracaibo drainage of northern South America. It was originally listed as Loricaria kneri and briefly diagnosed, cited as an unnamed species of Sturisoma in a type catalog of the Museo di Torino, Italy. In this work, the validity and authorship of the name Loricaria kneri are discussed, and S. kneri is made available. Sturisoma kneri is described as a new taxon and diagnosed based on interorbital width, osteological features of the roof of the skull, and number of plates in the midventral plate series.

A new species of the schilbid catfish genus Clupisoma Swainson, 1838, was discovered in the Salween River [= Nujiang] of western Yunnan Province, China. There are no previous records of schilbid catfish from the middle reaches of the Salween River before this discovery. Clupisoma nujiangense, new species, is the ninth species of the genus Clupisoma and only the third schilbid catfish species recorded from China.

The Quillfish, Ptilichthys goodei, is a slender, elongate fish distributed along the coastline of the North Pacific from Oregon to the Sea of Japan. It is the sole member of the monotypic family Ptilichthyidae, which is classified among the Zoarcoidei (eelpouts and their allies). Little is known of its osteology and there is much conflicting information in the literature regarding its morphology. In this paper we describe the skeleton of Ptilichthys based on newly collected and prepared specimens. Because of the small number and size range of our specimens, the emphasis of our study is on the juvenile skeleton, although the adult skeleton is also described as far as our material allows. We conclude by briefly discussing the phenomenon of axial elongation in Ptilichthys.

An experimental approach was taken to evaluate the role of phenotypic plasticity in reptile coloration for three lizard species which exhibit dramatic variation in dorsal body darkness associated with different substrate environments. In southern New Mexico, blanched color morphs of Aspidoscelis inornata, Holbrookia maculata, and Sceloporus undulatus inhabit the gypsum dunes of White Sands, and a melanic color morph of S. undulatus is found on the Carrizozo lava flow. Temperature was manipulated to determine the extent of physiological (rapid) plasticity in coloration for all three species. Color change in response to short-term stimuli did not explain the variation among lizards from different habitats. Although lizards of all color morphs were slightly darker when colder, more melanic lizards displayed a diminished capacity for rapid color change. Common garden experiments were conducted to evaluate the potential for ontogenetic plasticity in coloration for H. maculata and S. undulatus. Offspring from mothers of different substrate environments were distinguishable by color despite identical developmental conditions. Hatchlings and adults exhibited similar coloration for H. maculata, but a developmental trajectory in coloration was observed in S. undulatus. Overall, environmental variation alone did not explain differences in dorsal coloration among lizards from distinctive habitats. Results from these experiments support the hypotheses that color morphology in Tularosa Basin lizards has a strong heritable component and that observed variation is likely adaptive.

Adult male Eastern Fence Lizards (Sceloporus undulatus) possess blue and black ventral patches that function in sex recognition and intrasexual social signaling, but this ventral coloration is absent or greatly reduced in females and juvenile males. Adult males also exhibit a relatively uniform, reddish brown dorsal coloration, while females and juvenile males are cryptically colored, with two rows of dark brown or black chevrons set against a background of gray and brown. In the present report, we show that sexual divergence in ventral coloration is temporally correlated with sexual divergence in plasma testosterone in free-living juvenile males and females, supporting the hypothesis that sexual dichromatism is regulated at least in part by testosterone. We experimentally tested this hypothesis by (1) removing the primary source of circulating testosterone in juvenile males via surgical castration, (2) restoring testosterone in castrated males with tonic-release implants, and (3) implanting intact juvenile females with exogenous testosterone. As predicted by our hypothesis, the development of blue and black ventral coloration in S. undulatus was (1) inhibited by castration in juvenile males, (2) restored by exogenous testosterone following castration in juvenile males, and (3) promoted by exogenous testosterone in juvenile females. The expression of male-specific dorsal coloration was also (1) inhibited by castration and (2) restored by exogenous testosterone following castration in juvenile males. Our results are consistent with established literature supporting the critical role of androgens in the mediation of sexually dimorphic coloration among phrynosomatid lizards.

The genus Phallotorynus is revised and six species are recognized: P. fasciolatus, P. jucundus, P. victoriae, and three new species from the Paraná-Paraguay drainage, whose descriptions are provided. Phallotorynus dispilos, new species, can be distinguished from its congeners by its color pattern, the presence of sexually dimorphic teeth, and by a series of axial skeleton and gonopodium features. Phallotorynus psittakos, new species, can be autapomorphically diagnosed by a very large lateral process on base of fifth median anal-fin radial of adult males. Phallotorynus psittakos can be distinguished from its congeners by a combination of several characters such as number of dorsal-fin rays, color pattern, number of epipleural ribs, and gonopodial rays. Phallotorynus pankalos, new species, can be distinguished from its congeners, except P. jucundus, by six to nine dark brown round spots along lower half of flanks and by densely pigmented dorsal fin. Phallotorynus pankalos can be distinguished from P. jucundus by the number of dorsal-fin rays, number of anal-fin rays on females, by the absence of a dark ring around border of anus in females, and by the presence of a dark brown band on lower jaw. Diagnoses of intrageneric clades of Phallotorynus and descriptions of distributions for each species are provided, as well as a key for identification.

Fluorescent microspheres and confocal microscopy were used to assess matrotrophic transfer in livebearing poeciliid fishes. High levels of transfer occurred in an obligate matrotroph, Heterandria formosa, whereas low levels occurred in a proposed lecithotroph, Poecilia reticulata. Gambusia affinis and Gambusia geiseri, proposed facultative matrotrophs, exhibited variable transfer within each brood.

Stomach contents were obtained from 165 individuals of Lapemis curtus. Food was present in 90% of the stomachs, but only on 59 occasions prey could be identified to family level. Five fish families constituted the diet of L. curtus of which, Clupeidae and Cynoglossidae dominate. There was no significant difference in the proportion of the fish families represented in the diet with the size or sex of the snakes. There was variation in this proportion with the time of the day. The proportion of Cynoglossidae in the diet showed marked difference with time of the day. The study found no geographic variation in the feeding ecology of L. curtus in this region when compared to similar studies elsewhere. This species is a generalist in its feeding habits since it feeds on fish that inhabit different depths in the water column. These results suggest that L. curtus may be an ambush forager. During the trawls, the fish families that constituted 95% of the sea snakes diet were also being harvested.

Comparative ecological data on introduced populations can contribute to understanding why Eleutherodactylus johnstonei is a good invader. We studied the reproductive features of an introduced population of this species and compared them with similar data on other introduced and native populations. Females were larger than males; sexually mature males ranged between 17–29 mm snout vent length and females between 23–32 mm. Reproductive males and females were captured throughout the year and there were no monthly significant differences in their occurrence. Clutches and neonates occurred year-round. The adjusted testicular volume did not vary significantly among months and histological analyses of the testes and ducts revealed the presence of sperm through the year, indicating continuous reproductive activity for males. The ovarian volume did not vary significantly among months and the presence of yolked follicles were observed throughout the year, indicating that females also reproduce continuously. There was a positive relationship between female body size and the number of yolked follicles. Two different relationships associated with reproduction could explain sexual differences in body size; the larger body size in females allows greater clutch sizes, and the energy cost of calling activity and paternal care of the clutch limits male growth. The colonizing success of E. johnstonei appears to be related to its reproductive features, such as flexibility in reproductive activity, direct development, and parental care of the clutch, allowing it to easily occupy disturbed areas that it encounters.

We used data from a long-term field study of two populations of the Least Killifish, Heterandria formosa, to examine whether genetically based population differences in offspring size at birth are mainly due to differences in pre-fertilization offspring provisioning (i.e., differences in egg mass) or differences in post-fertilization offspring provisioning (i.e., the degree of matrotrophy). We found differences between populations in pre-fertilization offspring provisioning and larger differences in post-fertilization provisioning. These results establish population variation in H. formosa as a potential model for studying the costs and benefits that could modulate the evolution of matrotrophy. In addition, our results illuminate some of the costs and benefits associated with matrotrophy and offer insight into how matrotrophy influences the expression of other life history relationships, including that between female size and fecundity, the trade-off between offspring number and size, and the population-specific responses of offspring number and size to variation in population density.

To date, most research on sexual selection has focused on the discrimination between attributes of individuals of the opposite sex. We have demonstrated female discrimination of a male behavioral character, bower size, by experimentally manipulating bower height in a lek of cichlid fishes from Lake Malawi, Africa. Eggs increased significantly (p<0.01) with large (15 cm) and extra large (30 cm) artificial bowers. Males with extra large bowers received a 50% greater increase in eggs laid than those with just large bowers.

Fluorescence in situ hybridization (FISH) was used to identify which chromosome pairs are involved in the difference in karyotypes of three clonal lines of Rainbow Trout (Oncorhynchus mykiss): OSU with 2n = 60, Clearwater with 2n = 58, and Swanson with 2n = 58. These lines appear to have karyotypes typical of strains from the regions from which they were derived (California, Idaho, and Alaska, respectively). Bacterial artificial chromosome clones containing mapped markers specific for different acrocentric pairs in the OSU strain were hybridized to chromosomes of hybrid fish. The OSU × Clearwater and OSU × Swanson hybrids have 2n = 59 with a chromosome pair consisting of one metacentric (fusion) chromosome and two acrocentrics. Both strains have the same chromosome fusion involving acrocentric chromosomes 25 and 29 of the OSU strain although they are from widely separate geographic regions. These results suggest that all of the 2n = 58 Rainbow Trout may have the same karyotype and a common origin.

Lobotes surinamensis is a widely distributed marine perciform and is the sole member of the family Lobotidae, which has unclear phylogenetic affinities. In this paper we describe and illustrate a mode of tooth replacement in Lobotes that we name “grouped” tooth replacement. Lateral oral teeth are replaced intraosseously, i.e., developing replacement teeth can clearly be seen beneath them within both the dentary and premaxillary bones. In contrast to the more typically seen pattern of alternate replacement, the replacement teeth of Lobotes develop as a group within the bone, lying directly beneath the group of teeth that they will replace. Within each tooth replacement group, the teeth show an anteroposterior gradient in age. Within the category of fully functional teeth there is a clear anterior to posterior gradient of eruption within a tooth group. Grouped tooth replacement may be a synapomorphy of Lobotes and Datnioides. As in Lobotes, the lateral oral teeth of Datnioides also are replaced intraosseously and in groups, although they are smaller and the groups are neither as distinct nor as regular. The significance and polarity of this character, as well as other osteological similarities of Lobotes and Datnioides, are difficult to evaluate given the lack of understanding of higher level relationships among perciforms and the paucity of information about modes of their tooth replacement.

A new hybrid flatfish (Isopsetta isolepis X Parophrys vetulus) is described from two specimens collected in the Strait of Georgia and Puget Sound, Washington. Four putative parental species were selected based on morphological similarities to the hybrid. Principal component analysis was conducted on the correlation matrix for nine meristic characters. Parentage was assigned on the basis of meristic intermediacy between the hybrid and the putative parental species.

The recent examination of the holotypes of Callichthys thoracatus and Callichthys longifilis led to important modifications in the nomenclature of the two species of Megalechis. Inspection of these holotypes demonstrated that they represent the species that has commonly been referred to in current literature as Megalechis personata. Because C. thoracatus is an older name than C. personatus, it has priority and is considered as the senior synonym. Callichthys pictus is the oldest name applicable to the species commonly referred to in current literature as Megalechis thoracata, and is thus the valid name. Rearranged synonymies, updated diagnoses, and illustrations are provided for both species of Megalechis.

We investigated the structure of the eggshells of the oviparous scincid lizards, Lampropholis guichenoti and L. delicata, and the agamid Physignathus lesueurii. The eggshells of all three species consisted of an outer calcareous layer, a fibrous shell membrane, and an inner boundary layer. The eggshells of P. lesueurii had an additional amorphous layer between the calcareous and fibrous layers. The calcareous layer of all shells was relatively thin and contained calcium carbonate in the form of calcite, typical of oviparous squamates. The multilayered fibrous shell membrane constituted the majority of shell thickness. The calcareous layer contained the majority of inorganic ions, with calcium and magnesium being present in detectable quantities. Calcium carbonate crystals were also found on the inner boundary layer of the P. lesueurii shells. This phenomenon has only been described for one other species, the Tuatara.