Studies on reproductive biology of individual species provide data necessary for testing hypotheses that seek to explain the diversity of life histories observed in squamate reptiles. The reproductive cycle of Phyllodactylus lanei at Chamela Jalisco, Mexico was aseasonal and varied among months and between sexes. Males and females reached sexual maturity at 52.0 and 49.0 mm snout-vent length (SVL), respectively. Males and females were reproductively active throughout the year, but a distinct cycle was evident. Testes reached maximal size from August to March and began to decrease in size in April, reaching minimum size in July. Gonadal volume in females was greatest from January–April coincident with maximal egg production. However, some females were found with eggs in nine of the 12 months, indicating an extended egg-laying season. Some females (7.6%) contained eggs and vitellogenic follicles simultaneously. Females were capable of producing at least three clutches of two eggs during the reproductive season. The testicular cycle was correlated with photoperiod but not rainfall or temperature. The female gonadal cycle was correlated with mean monthly temperatures but not photoperiod or rainfall. Monthly production of oviductal eggs was correlated with monthly mean temperatures but not photoperiod or rainfall. Egg mass was significantly correlated with female mass but not with SVL. This study provides another example of a gecko species in which the reproductive season is extended, females reproduce repeatedly, but egg production is greatest during the dry season.

Estudios sobre la biología reproductiva de una especie proporcionan datos necesarios para probar hipótesis que traten de explicar la diversidad de historias de vida observadas en los reptiles squamata. El ciclo reproductivo de Phyllodactylus lanei de Chamela Jalisco, Mexico fue acíclico y varió entre meses y sexos. Los machos y las hembras alcanzares la madurez sexual a los 52.0 y 49.0 mm de longitud hocico-cloaca (LHC), respectivamente. Los machos y las hembras mostraron actividad reproductiva a lo largo del año, pero un ciclo distinto fue evidente. Los testículos alcanzaron el máximo tamaño de agosto a marzo, y comenzaron a decrecer en tamaño en abril, alcanzando el mínimo tamaño en julio. El volumen gonadal en las hembras fue más grande de enero a abril, coincidiendo con la máxima producción de huevos. Sin embargo, algunas hembras fueron encontradas con huevos en 9 meses de los 12, indicando una estación larga de puesta de huevos. Algunas hembras (7.6%) presentaron huevos oviductales y folículos vitelogénicos simultáneamente. Las hembras fueron capaces de producir al menos tres puestas de huevos durante la estación reproductiva. El ciclo testicular estuvo correlacionado con el fotoperiodo pero no con la precipitación o temperatura. El ciclo gonádico de las hembras estuvo correlacionado con la temperatura media mensual pero no con el fotoperiodo o precipitación. La producción mensual de huevos oviductales fue correlacionada con la temperatura media mensual, pero no con el fotoperiodo o lluvia. La masa del huevo fue significativamente correlacionada con la masa de la hembra pero no con la LHC. Este estudio proporciona otro ejemplo de una especie de gecko en la cual la estación reproductiva se extiende, las hembras se reproducen repetidas veces, pero la producción de huevos es más grande durante la estación de secas.

Paraxenisthmus cerberusi, described from four specimens from Augulpelu Reef, Palau, differs from its only congener (P. springeri from the Solomon Islands) in the following characteristics: pectoral fin rays 15–16 (vs. 18); posterior nasal (B) and ventral preopercular (Q′) cephalic lateralis pores absent (vs. present); head, nape, ventral abdomen, and dorsal midline of caudal peduncle naked (vs. scaled); and caudal peduncle with large black blotch (vs. no black blotch).

The whiptail lizard Aspidoscelis dixoni (Teiidae) comprises three distinctive color pattern classes (i.e., variants); A and B are restricted to Presidio County, Texas, and C is isolated over 500 km to the west-northwest in Hidalgo County, New Mexico. Pattern class E of A. tesselata is widely distributed in Chihuahua, Texas, and New Mexico. Genetic data have verified that these parthenogenetic species are hybrid-derivatives of A. tigris marmorata ♀ X A. gularis septemvittata ♂; however, the number of hybridization events involved in their origin has remained problematic. We used 19 lizards in laboratory skin-grafting experiments to test the histoincompatibility responses among A. dixoni A, B, C, and A. tesselata E. The results of these graft exchanges indicated that individuals of all four pattern classes were mutually histocompatible to skin grafts, a level of genetic homogeneity indicative of the origin of A. dixoni and A. tesselata from the same hybrid lizard. Thus, the color pattern variants A. dixoni A, B, C, and A. tesselata E are identifiable products of mutation and/or recombination in a single historical group. Such postformational genetic changes have not been shown to be capable of mimicking the mutual graft rejection responses that occur between all members of historical groups derived from different hybrid zygotes. Falsification of the hypothesis that A. dixoni and A. tesselata were derived from different hybrid individuals also nullified the generally accepted rationale for their treatment as separate species. Aspidoscelis dixoni is revealed to consist of a morphologically well-defined grouping of three of the several diploid color pattern classes (i.e., tokogenetic arrays) in the A. tesselata complex that are also potentially diagnosable as species using similar criteria. Based on histocompatibility data presented herein for the A. tesselata complex and a review of preexisting data for other taxa, we provide a comparison of published opinions pertaining to the taxonomic status of A. dixoni and A. tesselata and the other named parthenogenetic entities in the A. cozumela, A. sexlineata, and A. tesselata species groups of Aspidoscelis. This generic name was recently resurrected from the synonymy of Cnemidophorus; however, monophyly has yet to be achieved for the revised genus “Cnemidophorus” owing to paraphyly in the “C. lemniscatus” species group.

La lagartija cola de látigo Aspidoscelis dixoni (Teiidae) comprende tres clases distintivas de patrones de coloración (esto es, variantes); las clases A y B están restringidas al condado de Presidio, Texas, y la C está aislada a más de 500 km hacia el oeste-noroeste en el condado de Hidalgo, Nuevo Mexico. La clase E de A. tesselata está ampliamente distribuida en Chihuahua, Texas y Nuevo Mexico. Datos genéticos han verificado que estas especies partenogenéticas son derivadas de híbridos de ♀ de A. tigris marmorata y ♂ de A. gularis septemvittata; sin embargo, el núm

Three new species of the Neotropical electric fish Rhabdolichops are described from the lowland Central Amazon Basin of Brazil. These taxa are described using features of color pattern, morphometric and meristic traits, squamation, and osteology. Rhabdolichops nigrimans and R. navalha are known only from low-conductivity blackwater systems whereas R. lundbergi occurs almost exclusively in the main channel of high-conductivity whitewater rivers and adjacent floodplain channels. Rhabdolichops nigrimans and R. lundbergi are sister species, forming a sister clade to all other Rhabdolichops species, and retaining transitional phenotypes between the genera Eigenmannia and Rhabdolichops. Rhabdolichops nigrimans, but not R. lundbergi, displays a striking sexual dimorphism in caudal appendage length. Rhabdolichops navalha and R. stewarti are sister species nested within a clade comprising R. eastwardi and R. caviceps R. troscheli. Rhabdolichops navalha exhibits a unique morphology of the electric organ where the posterior margin ends abruptly and is replaced posteriorly by rigid and transparent non-electrogenic tissue.

Três espécies novas de peixes elétricos neotropicais, Rhabdolichops, são descritas da bacia Amazônica, Brasil. Estas espécies são descritas com base em características de pigmentação, morfologia, osteologia e dados merísticos. Rhabdolichops nigrimans e R. navalha são conhecidos exclusivamente de sistemas de águas pretas com condutividade baixa. Rhabdolichops lundbergi ocorre quase exclusivamente nas calhas principais dos rios de águas brancas e em canais de várzea (paranás) com condutividade alta. Rhabdolichops nigrimans e R. lundbergi formam um clado monofilético que representa um grupo irmão das demais espécies de Rhabdolichops. Estas duas espécies apresentam fenótipos transicionais entre os gêneros Eigenmannia e Rhabdolichops. Rhabdolichops nigrimans apresenta um dimorfismo sexual acentuado no comprimento do filamento caudal. Contudo, R. lundbergi não possui esta característica. Rhabdolichops navalha e R. stewarti são espécies irmãs dentro de um grupo monofilético constituido por R. eastwardi e R. caviceps R. troscheli. Rhabdolichops navalha apresenta uma morfologia única do órgão elétrico onde a sua margem posterior finda-se abruptamente e é substituída, posteriormente, por um tecido rígido e não-eletrogênico.

Three new frog species allied to Rana archotaphus are described from Laos and Vietnam. One new species from the Hoang Lien Mountains of northwestern Vietnam is characterized by having females with snout-vent length 66–68 mm, no visible pineal body, the first finger shorter than second, width of third finger disc about equal to tympanum diameter, and tympanum of males relatively larger than females. The second new species from northern Laos is characterized by having males with snout-vent length 38–44 mm, no visible pineal body, first finger shorter than second, width of third finger disc equal to the tympanum diameter, venter with very light or no spotting, and venter translucent. The third new species from the Northern Truong Son (Annamite Highlands) of Laos and the Kon Tum Plateau of Vietnam is characterized by having females with snout-vent length 56–57 mm, a visible pineal body, tympanum of males relatively equal to females, the first finger shorter than second, and males with width of third finger disc about half the tympanum diameter. Descriptions are expanded of several species that resemble the two new species: Rana archotaphus, R. daorum, R. iriodes, and Amolops chunganensis.

A new species of rubbernose armored catfish, collected by the Catherwood Foundation Peruvian Amazon Expedition from the upper Huallaga River (650 m elevation) in central Peru, is described herein. This new species differs from all other described Chaetostoma species in having a conspicuously banded dorsal fin and by the combination of the following characters: presence of fleshy excrescence on posterior tip of supraoccipital, typically nine branched dorsal-fin rays, and evertible cheek plates with two to four hypertrophied odontodes.

Una nueva especie de carachama nariz de goma colectada por la Catherwood Foundation Peruvian Amazon Expedition, en el alto Río Huallaga (650 m elevación) en Perú central es descrita. Esta nueva especie difiere de todas las otras especies descritas de Chaetostoma por tener una aleta dorsal conspicuamente bandeada, y por la combinación de los siguientes caracteres: presencia de una excresencia carnosa en el extremo posterior del supraoccipital; generalmente nueve radios dorsales ramificados; y placas evertibles de la mejilla con dos a cuatro odontodes hipertrofiados.

Movement and activity patterns are important aspects of the ecology and conservation of any organism. Among turtles, data on the behavioral ecology of hatchling stages are lacking. To increase our knowledge of hatchling turtles, I tracked 20 hatchling gopher tortoises (Gopherus polyphemus) for up to 335 days after hatching to determine movement patterns, refugia use, microhabitat use, and home range size. Consistent with other studies, hatchling gopher tortoises moved infrequently and over very short distances through their first winter, a period during which they are presumably receiving energy from yolk stores. With the onset of warm spring weather, hatchling tortoises began to move more, most likely to obtain energy after depleting yolk stores. Refugia included both burrows and pallets (short holes in the ground), which were surrounded by a high percentage of ground cover (81.4%) and tall (>50 cm) vegetation. Home range size estimations depended heavily on the number of different locations recorded for each individual and varied from 0.0001–4.8 ha, depending on the method of calculation and longevity of the hatchling. Hatchlings moved infrequently, spent large amounts of time in burrows and under tall vegetation, and moved short distances while changing refugia. However, these data represent some of the largest home range sizes reported for G. polyphemus to date, suggesting that dispersal and the hatchling life stage are important behavioral aspects that, if neglected, may result in underestimating spatial requirements necessary to support all ecological aspects of this declining species.

A new species of eelpout, Lycodes akuugun, is described from the Aleutian Islands on the basis of 11 specimens collected during bottom-trawl surveys from 1994 through 2004. This species has a distinctive color pattern, characterized by a dark brown dorsum separated from a light gray ventrum by a distinct border running along the lateral surface of the head and most of the body, as well as several distinct narrow bars on the dorsal fin and a light blotch on the posterodorsal portion of the caudal fin. It is also characterized by having an elongate body, a ventrally placed lateral line, rounded pectoral fins, and relatively high meristics, as well as the presence of an interorbital cephalic sensory pore and the absence of scales on the nape. Among sympatric congeners, L. akuugun is most similar to L. diapterus, L. brevipes, and L. concolor. It differs from all three species in color pattern and in the presence of an interorbital cephalic sensory pore. It can be distinguished from other congeners on the basis of coloration, lateral-line morphology, and meristics.

Rates of evaporative water loss (EWL) and cutaneous resistance (R_c) to water flux were measured for the two native frog species from the Fiji Islands: the Fiji Ground Frog, Platymantis vitianus, and the Fiji Tree Frog, Platymantis vitiensis (Anura: Ranidae). Surface area specific evaporative water loss was similar between the species: 10.2 (± 1.7) and 9.0 (± 1.7) mg cm⁻² h⁻¹ for P. vitiensis and P. vitianus, respectively. The total resistance (R_t) to water loss did not differ from estimates of similarly sized and shaped agar models (representative of a free water surface) for either species; thus, native Fijian frogs are “typical” anurans that have negligible cutaneous resistance (R_c) to EWL. Platymantis vitiensis is apparently able to exploit an arboreal habit, despite the concomitant increase in desiccating conditions, because of the humid environment of the Fiji Islands and by living near streams and rivers.

A new species of Apareiodon is described from the Rio Piquiri, upper Rio Paraná basin, State of Paraná, Brazil. This species occurs syntopically with one congener, A. piracicabae, with whom it shares the coloration pattern without dark vertical bands and/or blotches below lateral-line region but differs in the premaxillary teeth form, which is more pointed, and maxillary teeth number (one instead of two). However its morphological features, mainly teeth, are similar to A. ibitiensis, another congener that inhabits the upper Rio Paraná basin. Comparative diagnoses between the new species and the similar congeners based on aspects of coloration and morphology are provided.

The type species of the cyprinid genus Sinilabeo was misidentified as Varicorhinus tungting, and the species under the generic name belong to Bangana and Linichthys. In order to make Sinilabeo available, its type species is fixed under Article 70.3.2 of the 1999 edition of the International Code of Zoological Nomenclature as S. hummeli, a new species herein described from the upper Yangtze River basin in Chongqing City and Sichuan Province, South China. A re-definition is provided for Sinilabeo. It resembles Qianlabeo in having an upper lip only present in the side of the upper jaw and uncovered by the rostral fold, but missing in the median part of the upper jaw that, instead, bears a thin, flexible, and cornified sheath, covered by the rostral fold, a character that can separate both from all other existing genera of Asian labeonins. However, Sinilabeo is distinguished from Qianlabeo in the presence of a rostral fold disconnected from the lower lip; a broadly interrupted postlabial groove only restricted to the side of the lower jaw; an upper lip, which is only present in the side of the upper jaw, separated from it by a groove; 9–10 branched dorsal-fin rays; two pairs of tiny maxillary barbels.

Ecological data on poorly-known snake species can suggest novel hypotheses about selective forces for interspecific variation in morphological traits. The nocturnal fossorial snakes of the family Atractaspididae represent an ancient African radiation that may comprise the sister-group to other “advanced” snakes such as the Elapidae, but have attracted little ecological study despite their diverse and unusual morphology (including a unique “side-stabbing” mode of venom delivery in one lineage). Our measurement and dissection of 639 preserved specimens of six species showed that females attained similar or larger mean adult body sizes than did conspecific males in all six taxa, but males had relatively longer tails and, generally, relatively larger heads. The magnitude of sexual dimorphism varied considerably; for example, mean adult body sizes were similar in males and females for Atractaspis bibronii and Amblyodipsas ventrimaculata, but there was no overlap in adult body sizes between the sexes in Amblyodipsas polylepis. All species produced small clutches of relatively large eggs, but with significant interspecific variation in fecundity. Diets also differed, within a general pattern of specialization on elongate fossorial reptiles. Xenocalamus species mainly took amphisbaenians (at least during adult life), whereas Atractaspis, Amblyodipsas, and Macrelaps consumed a wider array of prey, especially snakes and burrowing skinks. In contrast to previous reports, we found few mammalian prey items in Atractaspis. Multiple evolutionary shifts in feeding structures (venom systems, head shapes, etc.) within this group may represent adaptations to taking fossorial prey in narrow burrows, and specifically to overcome the challenges posed by the ability of squamate prey to block burrows (and thus, impede predator pursuit) by tail autotomy.

The Walleye Pollack (Theragra chalcogramma) produces sounds by contractions of a pair of intrinsic sonic muscles located on the swimbladder. The innervation pattern of this muscle was investigated. It is innervated by branches (sonic branches) of the third to eighth spinal nerves. The Walleye Pollack was found to be one of the rare sonic fishes with the sonic muscle innervated only by the spinal nerves.

Chaunacops Garman, 1899, is shown to be a senior synonym of the chaunacid anglerfish genus Bathychaunax Caruso, 1989. While Chaunacops has not been used as valid since its erection in 1899, conditions do not exist to allow “reversal of precedence,” as provided by Article 23.9.1. of the International Code of Zoological Nomenclature. Thus, Chaunacops, type species Chaunax coloratus Garman by monotypy, must be regarded as valid and Bathychaunax set aside as a junior synonym.

Specimens of the pearlfish Carapus mourlani (Carapidae) were observed for the first time in association with the sea cucumber Isostichopus fuscus (Holothuroidea: Echinodermata) along the coast of Ecuador. Out of 4345 sea cucumbers collected from various depths between 5 and 60 m, 12 harbored a pearlfish either in the coelomic cavity, the respiratory tree, or the digestive tract, yielding a prevalence of ca. 0.0028. The presence of C. mourlani appeared to be detrimental to the holothurian host in some cases. Side effects resulting from coelomic cavity infections included less advanced gonad maturity (reduced gonadal tubule diameter and length, lower ratio of mature oocytes) and a significant proportion of necrotic and shriveled gonadal tubules, devoid of gametes. Aside from discussing this evidence, the present paper briefly describes the biology of the pearlfish, its relationship with the host, and its daily activity cycle.

Studies of ecological energetics in chelonians are rare. Here, we report the first measurements of daily energy expenditure (DEE) and water influx rates (WIRs) in free-ranging adult Gopher Tortoises (Gopherus polyphemus). We used the doubly labeled water (DLW) method to measure DEE in six adult tortoises during the non-breeding season in south-central Mississippi, USA. Tortoise DEE ranged from 76.7–187.5 kJ/day and WIR ranged from 30.6–93.1 ml H₂O/day. Daily energy expenditure did not differ between the sexes, but DEE was positively related to body mass. Water influx rates varied with the interaction of sex and body mass. We used a log/log regression model to assess the allometric relationship between DEE and body mass for Gopher Tortoises, Desert Tortoises (Gopherus agassizii), and Box Turtles (Terrapene carolina), the only chelonians for which DEE has been measured. The slope of this allometric model (0.626) was less than that previously calculated for herbivorous reptiles (0.813), suggesting that chelonians may expend energy at a slower rate per unit of body mass compared to other herbivorous reptiles. We used retrospective power analyses and data from the DLW isotope analyses to develop guidelines for sample sizes and duration of measurement intervals, respectively, for larger-scale energetic studies in this species.

We studied the courtship behavior of two species of chorus frogs, Pseudacris illinoensis and P. triseriata, in western Illinois. We report observations of courtship behavior and describe courtship calls for each species. These calls were given in response to both male and female conspecifics entering the calling spaces of resident males. Courtship calls given in response to an intruder were never followed by aggressive behaviors from the resident or the intruder, and courtship calls were never given in response to playbacks of conspecific advertisement calls. Thus, these calls do not appear to be used in an aggressive context. Courtship calls of P. illinoensis are longer in duration than advertisement calls. Courtship calls in P. triseriata consist of multiple notes compared to single note advertisement calls. These courtship calls have higher pulse rates and lower dominant frequencies, and they are given at faster calling rates than advertisement calls. Courtship calls of both species are more variable in structure within males than advertisement calls. Like two other species of chorus frogs for which courtship calls have been reported, courtship calls in P. illinoensis and P. triseriata are modifications of the advertisement call. Courtship calls in the genus that have been described so far do not appear to share a common structure. The recognition of courtship calls in a chorus may play a useful role in long-term monitoring of anuran breeding activity, especially in remotely determining the presence of gravid females.