A new species, Careproctus ambustus, is described from 64 specimens based on evidence from morphological and molecular data. Specimens of Careproctus ambustus, new species, have been historically misidentified as the common Blacktail Snailfish, C. melanurus. The new species is distinguished from C. melanurus by its higher numbers of vertebrae (62–66 vs. 56–62 in C. melanurus), dorsal-fin rays (57–63 vs. 53–58), and anal-fin rays (51–55 vs. 46–51), and longer pelvic disc (14.1–21.2 vs. 12.6–20.7 % HL). In addition, the new species differs from C. melanurus by seven base pairs within a 492-base-pair region of the cytochrome oxidase c subunit 1 region, a 1.4% sequence divergence. Careproctus ambustus, new species, is found at depths of 58–1,172 m and ranges from Japan, through Alaska, to the west coast of Vancouver Island, British Columbia, where its distribution overlaps with C. melanurus, which ranges from southern Alaska and British Columbia to Baja California.

When color pattern variation is co-adapted with other biological features, distinct color morphs may be separated along divergent niche axes, and data on niche partitioning can provide insight into how distinct color morphs are maintained over spatiotemporal scales. The Eastern Red-backed Salamander, Plethodon cinereus, contains two common color morphs (striped and unstriped) that differ along several trait axes in addition to coloration. Previous studies from a single population have suggested that dietary composition represents an important axis of ecological differentiation between morphs of P. cinereus. To determine if morphs partition prey resources over space and time, we collected stomach contents from morphs across six populations that ranged in color morph frequency from 100% striped to >99% unstriped, and sampled each population in a spring and a fall season. From each population and season, we also sampled leaf litter invertebrates to quantify morph differences in prey selection. Based on previous studies, we predicted striped morph diet would consist of higher quality prey in polymorphic populations, whereas in monomorphic populations, we predicted both morphs would have a more variable diet due to ecological release from intermorph competition. In the two polymorphic populations we examined, one showed no evidence of diet differences and the other mirrored differences reported from previous studies. There was no change in dietary breadth between polymorphic and monomorphic populations, and thus no signature of dietary release. Our results show there is a high degree of overlap between dietary and leaf litter invertebrates, suggesting both morphs of P. cinereus are generalist predators. Finally, we found dietary composition varied across seasons and populations, which demonstrates the importance of examining morph traits over spatial and temporal scales.

The ecology of many ectotherms depends heavily on their ability to navigate the surrounding thermal environment in a manner that maintains body temperature (T_b) within or near some optimal temperature range at least some of the time. From April–December 2016, we measured shell temperatures (T_s) and water temperatures (T_w) in two Spotted Turtle (Clemmys guttata) populations in southeastern Georgia using iButton temperature loggers. We attached radio transmitters and iButtons to the carapace of adult Spotted Turtles (n = 18 and 11 in each population, respectively) in early spring. Temperature loggers recorded a T_s measurement every 90 minutes (accuracy = 0.5°C), and we restricted our analyses to temperatures recorded between sunrise and sunset. Monthly mean T_s ranged from 12.3±3.4 to 27.1±2.7°C (SD), and seasonal variation accounted for a majority of the observed variation in temperatures. We found a strong positive correlation between weekly mean T_s and weekly mean T_w at one site that remained flooded throughout the study (P < 0.0001, R² = 0.99). T_w could not be measured at the other site because it dried completely early in the study. Spotted Turtles did occasionally (<5% of total temperature observations) bask to raise T_s above that of the surrounding T_w. Gravid females achieved significantly higher daily maximum temperatures (26.2°C) than males (24.5°C) during the four weeks surrounding egg development (P = 0.043). In general, Spotted Turtles at the southern end of their range appear to spend a majority of their time conforming to environmental temperatures that often fall within the preferred range for the species.

During recent field expeditions to an Amazonian region in eastern Guiana Shield (Serra do Navio, state of Amapá, northern Brazil), we collected and recorded calls of a species of Adelophryne, a diminutive leaf-litter-dwelling, direct-developing frog genus. After a careful integrative taxonomic evaluation using morphological, molecular, and bioacoustic data, we concluded that the series of specimens collected represent a new taxon, which we describe herein. The new species of Adelophryne is distinguished from all ten congeners by the following combination of character states: (1) male SVL = 12.5 mm; female SVL = 13.0–14.4 mm; (2) tympanic membrane present; (3) tympanic annulus present, incomplete; (4) vomerine teeth absent; (5) finger terminal discs absent; (6) tips of Fingers I–IV mucronate; (7) finger pads present (formula 1–1–2–1); (8) three phalanges in Finger IV; (9) dorsum smooth; (10) cloacal flap absent; (11) multi-note advertisement call composed of non-pulsed notes; (12) the call dominant frequency (4,802–5,706 Hz) coincides with the fundamental harmonic. Our study describes the eleventh species of Adelophryne, and, despite the increase in taxonomic knowledge within the past few years, there are still some species in the genus lacking a formal taxonomic description.

Variation in lighting environments creates different demands of visual systems for the successful detection and interpretation of visual signals. Eye size is a critical property of the visual system as it has strong effects on visual acuity and visual sensitivity. While many comparative studies have examined eye size across fishes that live in disparate lighting environments (i.e., caves versus surface habitats, mesopelagic versus pelagic depths, turbid versus clear water, diurnal versus nocturnal), fewer have investigated differences in eye size as a function of water clarity at the among-population level. Here, we compared relative eye size (eye size residuals on standard length) among wild-caught Bluefin Killifish (Lucania goodei) from tannin-stained swamps and clear springs across four drainages in Florida. We also performed a laboratory rearing experiment where we reared animals in clear and tea-stained water, which mimic spring and swamp conditions, to determine whether phenotypic plasticity as a function of lighting conditions influences relative eye size. Field caught animals varied greatly in relative eye size among populations, but there was no clear relationship with lighting environment. Fish from the two southern drainages (Everglades, Withlacootchee) had greater relative eye size than two northern drainages (Suwannee, North Florida). However, the results of our laboratory rearing experiment indicated that fish reared in clear water had slightly larger eyes compared to those in tea-stained water. While there are small effects of lighting environment on eye size, there are additional unknown genetic and environmental/ecological factors that influence adult eye size.

Traditional tagging methods for fishes can have issues relating to both animal welfare and economic costs. Biometric data such as iris patterns can be captured via digital cameras, which allows for non-invasive tagging and inexpensive and rapid analysis. The purpose of this study was to investigate if the iris of Atlantic Salmon (Salmo salar) is a suitable biometric template for long-term identification of individuals. Atlantic Salmon were individually tagged in the body cavity using PIT tags at the juvenile pre-smolt stage, and the left eye was photographed six times over a 533-day period. Changes in iris stability were assessed both qualitatively and using iris-recognition software. Identification of individual Atlantic Salmon using the iris was not successful over the entire period, as the iris pattern changed significantly with time. Over a shorter time period (four months) with frequent samplings, iris software was able to correctly identify individual fish. The results show that iris identification has potential to replace other methods for Atlantic Salmon over short timeframes.

Animals can obtain social information from monitoring chemical cues in their environment left behind by conspecifics, competitors, predators, or prey. Whereas many studies have addressed the ability of snakes to trail scents in the laboratory along a homogeneous substrate (i.e., butcher paper), our objective was to determine if the scent-trailing behavior of a snake was affected by changes in substrate type (paper, sand, leaf litter, and burnt leaf litter). We brought five pregnant Timber Rattlesnakes (Crotalus horridus) into the laboratory where each gave birth to an average of nine newborns. After each newborn shed, we conducted Y-maze trials. The scent of the mother was applied down one arm of the Y-maze. Each newborn was tested on each substrate. Newborns non-randomly chose the arm with the mother's scent 87% of the time when tested on paper (P < 0.001) and 73% of the time when tested on sand (P = 0.011). When tested on leaf litter and burnt leaf litter, newborns chose the arm with the mother's scent 67% and 53% of the time (P = 0.068 and P = 0.715, respectively). Newborns also took longer to complete trials on paper compared to other substrates (F_3,112 = 10.26, P> < 0.001). Thus, substrate affected the ability of newborns to scent-trail their mother. In a natural setting, the heterogeneity of substrates may facilitate scent-trailing behavior as more conducive substrates may be present among substrates that impede scent-trailing behavior. However, as prescribed fire becomes a more popular forest management tool, care should be taken in where this tool is applied.

A major driver generating amphibian diversity in the Appalachian Mountains is the complex paleogeography of the zone. Although the Appalachian Mountains have been widely studied, much of its amphibian phylogeography remains poorly known. The Mountain Chorus Frog (Pseudacris brachyphona) is one example of an understudied organism due to its elusiveness, patchy distribution, and short breeding seasons. Phylogenetic studies have suggested the existence of divergent lineages within P. brachyphona; however, insufficient sampling and the lack of diagnostic morphological traits have prevented further assessment of their taxonomic status. Using a genome-wide nuclear data set obtained via anchored hybrid enrichment, acoustic data, and ecological modeling, we tested for the existence of cryptic species within P. brachyphona. Our species tree estimation supports previous mitochondrial-based phylogenetic hypotheses that separate P. brachyphona into the Northern and Southern clades. Population genetic clustering also shows a sharp genetic break, which is concordant with these clades. Admixture was observed between the Northern clade and another chorus frog species (P. feriarum). Analysis of advertisement calls shows a divergent, faster pulse rate, and higher dominant frequency call for the Southern clade in comparison to the Northern clade and other trilling chorus frogs. Furthermore, species distribution models showed that habitat suitability for the Southern clade included pine-dominated and drier areas compared to the Northern clade. In light of the genetic, acoustic, and ecological divergence between the clades, we propose to elevate the taxonomic status of the Southern clade and name this new species the Collinses' Mountain Chorus Frog (P. collinsorum, new species). The new species ranges across northern Alabama, and extends into Georgia, eastern Mississippi, and southern Tennessee. Pseudacris collinsorum, new species, is geographically separated from its sister species, P. brachyphona, by the Tennessee River and surrounding Blue Ridge Escarpment. This study highlights the need for genus-wide, population-level genetic assessments and integrative data sets to uncover diversity within anurans.

Achalinus, commonly known as odd-scaled snakes due to their unique scutellation, are a fascinating group of xenodermid snakes distributed throughout east Asia. Currently, northern Vietnam is known to host six species of Achalinus, three of which are considered endemic. During recent herpetofaunal surveys conducted in the Bac Me District of Ha Giang Province, we collected a single specimen of Achalinus in a lowland region surrounded by secondary forest on karst. We conducted Bayesian and maximum likelihood phylogenetic analyses using multiple mitochondrial protein-coding loci and a ribosomal subunit to ascertain the phylogenetic position of the Ha Giang specimen among currently recognized odd-scaled snake species. The results of those analyses along with morphological differences support this specimen as representing a new species, which we describe as Achalinus zugorum, new species. We provide detailed morphological descriptions and comparisons of the new species as well as brief comments on the biogeography and conservation of Achalinus in northern Vietnam.

This study provided a first detailed description of the acoustic calls and the possible sound production mechanism in the Giant Sea Bass (Stereolepis gigas). Passive acoustic (hydrophone) recordings of Giant Sea Bass sounds were made of three mature individuals (40–45 kg) held in a circular 17,000 l seawater tank isolated from other fish species. Four basic sounds plus combinations were identified from the tank recordings when fish were present and were encountered on numerous occasions throughout the study. We classified the basic sounds as two types of pulses (A and B), short bursts, and long bursts, and combinations of short and long bursts. Mean peak frequencies of the four sound types were less than 39 Hz, while mean durations ranged from 67 ms to 545 ms, depending on sound type. We also obtained and dissected two mature, adult Giant Sea Bass to describe the morphology of a putative sound production mechanism. Five putative sonic muscles were discovered between each of the first six pleural ribs of the male examined. These five massive muscles (=obliquus superioris?) unite ribs 3 to 9 and were found at the level of the deep hypaxial musculature. The identification of these sounds and accompanying sonic mechanism marks the first occurrence of sound production in the family of wreckfishes (Polyprionidae). This knowledge of the acoustic characteristics increases our ability to document the presence, activity, and possibly the abundance of this critically endangered species at spawning sites.

A new species of Careproctus is described on the basis of two individuals collected from the eastern Beaufort Sea during the U.S.–Canada 2013 Transboundary Cruise. It is distinguished from all known species of Careproctus primarily by its elongate deeply exserted filamentous rays in the middle part of the pectoral fin, an unlobed dorsal fin, protruding snout, and counts of dorsal- (58–60) and anal-fin rays (52–54) and vertebrae (64–65). The two known specimens were collected at depths of 488–599 m. Among other liparids of the Arctic and North Pacific Oceans, the new species is most similar to Careproctus mica, from which it can be readily distinguished by the filamentous rays of the pectoral fin and higher counts of median-fin rays and vertebrae.

In this study, we use a geometric morphometric and a character evolution approach to study the evolutionary patterns of body-shape change and habitat transition in the Aulopiformes. Aulopiform fishes (lizardfishes; 289 spp.) inhabit diverse marine habitats from coral reefs to the deep sea and exhibit a wide range of body morphologies. Herein, we examine over 400 aulopiform specimens representing 38 of 44 genera and all families and identify that there are distinct patterns of body-shape change across the aulopiform radiation that coincide with habitat. A fusiform (torpedo-shaped) body is predominant among aulopiforms distributed in inshore-benthic and deep-sea benthic environments (e.g., Aulopidae, Bathysauridae, Synodontidae). There is a trend towards body elongation in taxa distributed in deep-sea pelagic habitats at depths of 200–4,000 meters (e.g., Alepisauridae, Lestidiidae, Notosudidae, Paralepididae) and a trend of body elongation with more centrally positioned dorsal and anal fins in the deep-benthic family Ipnopidae (tripodfishes). Additionally, deep-sea pelagic aulopiforms exhibit the largest variance in body-shape disparity with significant shape disparity compared to aulopiforms found in inshore-benthic and deep-sea environments. Deep-sea benthic lineages also have significantly higher body-shape variance and disparity compared to inshore-benthic lineages. We identify that there are considerable changes in body shape as aulopiform lineages transitioned to differing marine habitats. We infer the common ancestor of aulopiforms to have lived in a deep-sea benthic environment with a single transition to an inshore-benthic environment in the common ancestor of the Aulopoidei (lizardfishes, flagfin fishes) and two independent transitions into deep-sea pelagic environments, once in the common ancestor of Giganturidae, and once in the common ancestor of Alepisauroidea + Notosudoidea. This is the first study to quantitatively investigate changes in the body shape of aulopiform fishes tied to habitat transitions in marine environments from the deep sea to coral reefs. Our findings suggest that aulopiform body plans have broadly diversified in deep-sea pelagic and benthic habitats while remaining comparatively conservative in inshore-benthic habitats.

Lepadichthys conwayi, new species, is described on the basis of 42 specimens (13.0–42.0 mm in standard length [SL]) collected from the central South Pacific and characterized by the following combination of characters: head sensory canal pores well developed, including 2 nasal, lacrimal and postorbital, and 3 preopercular pores; 13–16 (modally 15, rarely 16) dorsal-fin rays; 11–14 (12, rarely 14) anal-fin rays; 27–30 (28) pectoral-fin rays; 8 or 9 (9), 8–11 (9), and 8–11 (9) gill rakers on first to third arches, respectively; upper end of gill membrane level with base of 7^th to 10^th (usually 9^th) pectoral-fin ray in lateral view; disc length and width 15.0–17.1 (mean 16.0) and 11.1–16.1 (13.9) % SL, respectively, disc length plus disc width 27.8–33.2 (30.0) % SL; dorsal and anal fins with very weak membranous connections to (rarely separated from) caudal fin, posteriormost points of membranes usually just short of or just reaching vertical through caudal-fin base, otherwise very slightly beyond fin base; dorsal- and anal-caudal membrane lengths 3.4–7.1 (4.8) and 3.0–6.0 (4.8) % of caudal-fin length, respectively; black stripe on snout tip through eye to posterior region of head. In addition, examination of the type specimens of Lepadichthys springeriBriggs, 2001 revealed them to be conspecific with L. misakius (Tanaka, 1908), a valid species recently resurrected from the synonymy of L. frenatus Waite, 1904. Accordingly, L. springeri is regarded as a junior synonym of L. misakius.

Habitat loss and fragmentation are among the greatest threats to wildlife and biodiversity. Reptiles are particularly susceptible to these threats due to high site fidelity, large home ranges, and slow movement rates. To understand behavioral responses of Eastern Milksnakes (Lampropeltis triangulum) to fragmentation, we compared home range size and movement rates between a fragmented habitat and an intact habitat. Additionally, we quantified road avoidance and habitat selection in the fragmented habitat. In 2015 and 2016, we collected 453 locations from 17 individuals from Rouge National Urban Park (RNUP), the fragmented study area, using radio-telemetry. We compared our results to a previous study with 1,001 locations from 30 individuals at Queen's University Biological Station (QUBS), our intact study area, collected from 2003 to 2004. We found that home ranges were smaller, but daily movement rate (DMD) and distance-per-move (DPM) were greater in the fragmented study area. We also observed that road crossings by snakes occurred less than expected, suggesting active avoidance of roads. Milksnakes in the fragmented habitat selected locations with a greater number of cover objects within open patches surrounded by high density vegetation, which is consistent with previous findings from the intact habitat. Our findings suggest that Eastern Milksnakes benefit from heterogeneous microhabitats and an abundance of available anthropogenic or natural cover.

We studied annual trends and characteristics of nesting activities and hatchling production by female Komodo Dragons (Varanus komodoensis) in Komodo National Park, Indonesia between 2002 and 2006. During this period, we recorded 12, 16, 15, 13, and 6 females nesting annually at 42 potential nesting sites. An average female nesting periodicity was estimated at 1.2±0.4 years. This result arose because most females bred annually and some biennially. Some females reused nest sites in successive years while others did not. Nesting females had significantly lower body mass compared to when they were recaptured again in a non-nesting state. All-female nesting activities were conducted within their resident valleys and suggested a strong tendency for spatial fidelity. Komodo Dragons were generally considered solitary nesters as only on one occasion were two nesting females observed to use the same nesting site. On average, 21.0±3.6 Komodo Dragon hatchlings emerged from each nest. We estimated that within the study area, nesting female Komodo Dragons produced between 129.0±21.8 and 344.0±58.16 hatchlings per annum. We discuss the ecological and evolutionary significance of these attributes. However, the main conservation management implications drawn from this study are that there are a low annual number of nesting females and associated hatchling production in Komodo National Park. Hence, a continuation of more extensive nesting surveys could provide a cost-effective and accurate way to gather important long-term demographic information for this species.

Gobies (family Gobiidae) have a complex mechanosensory lateral line system characterized by reduced lateral line canals and a dramatic proliferation of small superficial neuromasts (on “sensory papillae”), which are arranged in lines on the head, trunk, and tail. A suite of morphological methods was used to describe the distribution and morphology of canal and superficial neuromasts in the neon goby, Elacatinus lori, and to describe the ontogeny of the lateral line system for the first time for any gobiiform fish. Portions of only three cranial lateral line canals are retained and they contain a total of eight canal neuromasts. In addition, 128–155 superficial neuromasts are found in six head series (comprising 33 neuromast lines or rows). Superficial neuromasts are found in one body series (65–80 neuromasts arranged in three groups of vertical lines or “stitches”) and one caudal fin series (3 lines, each located between fin rays and comprised of many small neuromasts; total of 27–53 neuromasts) extending to the tip of the caudal fin. The general distribution of neuromasts is established early during the larval stage, and neuromast numbers increase within and among lines resulting in an increase in overall complexity of the system. On day-of-hatch, a total of 22 neuromasts are present. At ∼15 days post-hatch, all eight cranial canal neuromasts are present, and, in post-settlement juveniles (“settlers”), they are enclosed in canals and a total of ∼185 neuromasts are found on the head, trunk, and tail. All neuromasts are small (∼40 lm long) and diamond-shaped, but three subpopulations (canal neuromasts, canal neuromast homologs, superficial neuromasts) are defined based on their location and their arrangement within lines (“tip-to-tip” or “side-by-side”). The ontogeny of the lateral line system and distinctions among neuromast subpopulations help to reveal the structural and functional organization of the complex lateral line system in Elacatinus and will contribute to the interpretation of neuromast patterns in other gobiiforms. A comparison of superficial neuromast number in 12 species of Elacatinus and Tigrigobius (sister genera) revealed variation among species that live in different reef microhabitats, which suggests that adaptive evolution in the lateral line system is evident among closely related taxa.

Gobiesocidae are a moderate-sized family (currently 182 species, 51 genera) of predominantly coastal marine fishes, commonly referred to as clingfishes. Depending on the classification adopted, the species and genera of clingfishes are organized either across ten subfamilies, based on a classification scheme introduced in the 1950s (“traditional” classification, comprising Aspasminae, Cheilobranchinae, Chorisochisminae, Diademichthyinae, Diplocrepinae, Gobiesocinae, Haplocylicinae, Lepadogastrinae, Protogobiesocinae, and Trachelochisminae), or just two subfamilies, in a classification scheme adopted only recently (“reduced” classification, comprising Cheilobranchinae and Gobiesocinae). We investigated the phylogenetic relationships among members of the family Gobiesocidae using both mitochondrial and nuclear DNA sequence data to assess whether the alternative classification schemes (traditional and reduced) are compatible with inferred evolutionary relationships. Phylogenetic hypotheses are derived from maximum-likelihood and Bayesian analyses of a seven-gene concatenated dataset (2 mitochondrial and 5 nuclear markers; 4,857 bp) compiled from individuals representing 82 (of 182) species, 42 (of 51) genera, and 10 (of 10) subfamilies of the Gobiesocidae. Although our investigation provides strong support for the monophyly of the Gobiesocidae, multiple subfamilies of the traditional classification (Aspasminae, Diademichthyinae, Diplocrepinae, Gobiesocinae, and Trachelochisminae), one subfamily of the reduced classification (Gobiesocinae), and multiple genera (Aspasmichthys, Cochleoceps, Lepadogaster, and Lepadichthys) are resolved as non-monophyletic groups. Based on our results and the results of previous studies, we recommend a systematic reassignment of genera between subfamilies, of which we recognize nine: Cheilobranchinae, Chorisochisminae, Diademichthyinae, Diplocrepinae, Haplocylicinae, Gobiesocinae, Lepadogastrinae, Protogobiesocinae, and Trachelochisminae. Membership of the Lepadogastrinae is unchanged from previous usage; the Cheilobranchinae are expanded to contain additional genera from southern Australia, including those placed previously in the Aspasminae (Nettorhamphos and Posidonichthys) and the Diplocrepinae (Barryichthys, Cochleoceps, and Parvicrepis); the Aspasminae are placed in the synonymy of the Diademichthyinae and all genera placed in the former (excluding Modicus and Posidonichthys) are transferred to the latter; the Diplocrepinae are restricted to Diplocrepis; Eckloniaichthys scylliorhiniceps is transferred from the Gobiesocinae to the Chorisochisminae; Gobiesocinae are restricted to the New World members of this group (Acyrtops, Acyrtus, Arcos, Derilissus, Gobiesox, Rimicola, Sicyases, and Tomicodon); the Haplocylicinae are expanded to include additional genera from New Zealand (Gastrocyathus, Gastrocymba, and Gastroscyphus); the Protogobiesocinae are expanded to accommodate three genera of deep water taxa (Gymnoscyphus, Kopua, and Protogobiesox); and the Trachelochisminae are restricted to Dellichthys and Trachelochismus. Four genera (Aspasmogaster, Conidens, Creocele, and Modicus) of uncertain placement are not assigned to any subfamily herein and are considered incertae sedis within the Gobiesocidae.

The Philippine archipelago is an exceptionally biodiverse region that includes at least 112 species of land snakes from 41 genera and 12 families. Recently, Cyclocoridae (formerly Lamprophiidae: Cyclocorinae) was proposed as a distinct, Philippine-endemic family, containing four genera: Cyclocorus, Hologerrhum, Myersophis, and Oxyrhabdium. Here, we describe an additional cyclocorid genus and species, Levitonius mirus, new genus and species, from Samar and Leyte Islands, Philippines. Molecular data support Levitonius, new genus, to be most closely related to Myersophis and Oxyrhabdium, and it shares multiple skeletal characteristics with these genera; Levitonius, new genus, differs from all of these taxa in body size, scalation, and other characters. Skeletal and other phenotypic data suggest that Levitonius, new genus, is fossorial and likely has a diet that is specialized on earthworms. Levitonius mirus, new genus and species, has a maximum total length of 172 mm and is at present the smallest known species in Elapoidea. Our results highlight the need for future work on Samar and Leyte Islands, which have received relatively little attention from systematists, in part because of a prevailing biogeographic paradigm that predicted (not necessarily correctly) that these islands would simply have a nested faunal subset of the Mindanao faunal region land vertebrates. The discovery of a strikingly distinct and phylogenetically divergent snake lineage on these landmasses joins numerous related studies calling for a wholesale reconsideration of the Pleistocene Aggregate Island Complex model (the PAIC paradigm of diversification) biogeographic framework.

We describe a new species of the South American frog genus Adenomera, based on external morphology, color patterns, advertisement call, and mtDNA sequences. The new species was collected from the Japurá River basin in northwestern Brazilian Amazonia and is distinguished from all congeners by the combination of large snout–vent length (SVL), toe tips unexpanded, presence of antebrachial tubercle on underside of forearm, and by a multi-note advertisement call composed of non-pulsed notes. This new species is part of the A. lutzi clade together with a candidate new species known as Adenomera sp. P and A. lutzi. The three species have the largest SVL in the genus. The presence of toe tips fully expanded and a single-note advertisement call distinguish A. lutzi from the new species. Acoustic and morphological data are still required to assess the taxonomic identity of Adenomera sp. P. Our new species of Adenomera is the third anuran species described from the Solimões-Japurá interfluve. This flags this poorly known region of lowland forests as an important area of species richness in northwestern Amazonia.

A new species of colorful snakehead from Meghalaya, northeastern India is distinguished from all its congeners by possessing a uniform bright blue to bluish-green body, bright-blue dorsal, anal, and caudal fins, submarginally black with white distal margin, series of brown to maroon-red, rounded, oblong or clover-shaped blotches or spots on dorsolateral, postorbital, and ventrolateral region of head, continued on body forming oblique pattern or randomly distributed. The new species superficially resembles C. pardalis and C. bipuli in appearance, but it can be distinguished from both in having brown to maroon-red, rounded, oblong or clover-shaped blotches or spots on head and sides of the body (vs. possession of well-defined, black to brown, rounded to oblong spots), fewer pre-dorsal scales (7 vs. 8–9), more caudal-fin rays (15 vs. 13), and more vertebrae (49 vs. 45). The new species differs from both C. pardalis and C. bipuli by Kimura's two-parameter (K2P) distance of 4.2–4.8 and 4.9–6.0% in the coxI gene sequence. A key to the snakehead Gachua group of the Eastern Himalayan region is provided herein.

Homing is a behavior in which an animal returns to a specific place after they have moved or migrated to a distant place. In anurans, most of our knowledge about homing comes from studies in temperate-region species with nocturnal activity and reproduction associated with ponds. Recently, studies with poison frogs (Dendrobatidae) have increased our understanding about homing in tropical frogs with diurnal activity, and that do not breed in large ponds. The Rubí Poison Frog Andinobates bombetes offers a good opportunity to further increase the knowledge of behavioral ecology of homing in anurans because some natural history traits in this species differ from those exhibited in most poison frogs in which homing ability has been studied. For instance, A. bombetes have a smaller body size and use phytotelmata in bromeliads for tadpole development while others use terrestrial pools. To quantify the homing ability and the factors influencing it in A. bombetes, we performed translocation experiments of individuals at distances between 5 and 90 m outside their territory in a forest remnant located in the department of Quindío, Central Andes of Colombia. In this study, we included a large sample size of females, which is important because homing studies with poison frogs has been almost exclusively studied in territorial males. Of 104 displaced individuals, 39 returned to their territory. The probability of homing in A. bombetes was negatively related to the translocation distance, but was unrelated to body size and sex. Apparently, this species has a limited homing ability when compared to most poison frogs studied so far except for O. pumilio, which seems more similar in body size and resources used for reproduction. Overall, homing ability appears to be widely shared in the family Dendrobatidae, Andinobates being the fourth genus of this family for which homing ability has been corroborated experimentally.

Resource partitioning in communities is often achieved by sympatric species having different morphologies that allow them to access different resources. This is because differences in morphology influence an organism's capability to perform a task that is relevant to their ecology. Here, we compare limb, shell, and head morphology, swimming performance, habitat use, and diet of three species (Rhinoclemmys rubida, R. pulcherrima, and Kinosternon chimalhuaca) that co-occur in the tropical dry forest of Chamela, Jalisco, Mexico. We found that these species do not overlap in both habitat or diet, and the overlap that we observed in habitat was contrasted by differences in diet. We also found a consistent relationship among limb and shell morphology, swimming speed, and habitat. Rhinoclemmys rubida occupies the driest deciduous forest atop and along hills, has shorter hands, less interdigital webbing, longer plastrons, more-domed shells, and slower swimming speeds in proportion to body size. In contrast, Kinosternon chimalhuaca exclusively occupies arroyos or seasonal streams, has longer hands, more interdigital webbing, smaller plastrons, less-domed shells, and faster swimming speeds in proportion to its body size. Rhinoclemmys pulcherrima was found in all habitats and intermediate in morphology and swimming speed between the other two species. Therefore, in this study system, limb and shell morphology are good indicators of habitat differences between turtle species. These differences are likely due to the influence that limb and shell morphology have on swimming performance. Relationships between head morphology and diet were less clear, which might be the result of changes in behavior or habitat rather than morphology. Patterns of resource partitioning in Chamela seem to coincide with other studies of turtle communities, which suggests that relationships among morphology, performance, and ecology that we observe here might be a general pattern across turtles.

We describe through integrative taxonomy a new Amazonian species of leaf-litter toad of the Rhinella margaritifera species group. The new species inhabits open lowland forest in southwest Amazonia in Brazil, Peru, and Bolivia. It is closely related to a Bolivian species tentatively identified as Rhinella cf. paraguayensis. Both the new species and R. paraguayensis share an uncommon breeding strategy among their Amazonian congeners: each breeds in moderate to large rivers instead of small streams or ponds formed by rainwater. The new species is easily differentiated from other members of the R. margaritifera species group by having a strongly developed bony protrusion at the angle of the jaw, a snout–vent length of 63.4–84.7 mm in females and 56.3–72.3 mm in males, well-developed supratympanic crests with the proximal portion shorter than the parotoid gland in lateral view, a divided distal subarticular tubercle on finger III, and multinoted calls composed of groups of 7–9 pulsed notes and a dominant frequency of 1,012–1,163 Hz. Recent studies have shown that the upper Madeira Basin harbors a megadiverse fauna of anurans, including several candidate species. This is the first member of the R. margaritifera species group to be described from this region in recent years, and at least two additional unnamed species await formal description.

Hybridization between populations along the path to complete reproductive isolation can provide snapshots of speciation in action. Here, we present a comprehensive list of salamander hybrids and estimate genetic distances between the parental hybridizing species using one mitochondrial and one nuclear gene (MT-CYB and RAG1). Salamanders are outliers among tetrapod vertebrates in having low metabolic rates and highly variable sex chromosomes. Both of these features might be expected to impact speciation; mismatches between the mitochondrial and nuclear genomes that encode the proteins for oxidative metabolism, as well as mismatches in heteromorphic sex chromosomes, can lead to reproductive isolation. We compared the genetic distances between hybridizing parental species across four main tetrapod groups that differ in metabolic rates and sex chromosome diversity: salamanders, lizards, mammals, and birds. Our results reveal no significant differences, suggesting that variation in these traits across vertebrates does not translate into predictable patterns of genetic divergence and incompatible loci in hybrids.

The genus Chapalichthys (Cyprinodontiformes: Goodeidae) consists of three allopatrically distributed species that occur on the Mesa Central, Mexico. Chapalichthys encaustus primarily occurs in the Río Lerma-Santiago basin, whereas both C. peraticus and C. pardalis have restricted distributions in the adjacent Río Balsas basin. Taxonomic issues in the genus center around the validity of C. peraticus. A formal systematic and taxonomic assessment of the genus inclusive of all three species of Chapalichthys has never been conducted. Therefore, the objectives of this study were two-fold: 1) to assess the phylogenetic relationships among multiple populations and all three species of Chapalichthys using 1,047 bp of mtDNA (ND2) sequence data, and 2) in light of the phylogenetic results, to re-examine the taxonomic status of C. peraticus using meristic and pigmentation characters. The phylogeny indicates two clades, each consisting of a valid species. One clade includes multiple populations of C. encaustus, and a second clade consists of multiple individuals of C. pardalis and C. peraticus. Chapalichthys pardalis and C. peraticus possess nearly identical mitochondrial sequences for ND2. Morphologically, meristic counts of all characters examined showed overlap for all three species and provide no species-specific diagnostic information. Chapalichthys encaustus can be differentiated from C. pardalis and C. peraticus based on the presence of vertical bars along the lateral flank versus a spotted pattern in the other two species. Chapalichthys pardalis and C. peraticus cannot be differentiated from one another based on pigmentation or meristics. The results from this study support the recognition of only two species of Chapalichthys: C. encaustus and C. pardalis.