Translocations of captive-reared animals are commonly used to stabilize declining wildlife populations. However, captive-reared animals are often raised in conditions dissimilar to their release sites and lacking natural characteristics, which could alter movement patterns and postrelease survivorship. These patterns can be further altered by season of release and soft-release conditions. We reared juvenile Eastern Hellbenders (Cryptobranchus alleganiensis alleganiensis) for 18 mo in captivity in one of two conditions: a control condition with low-velocity water flow (unconditioned) or a treatment condition with moving water (conditioned) that simulated natural flow velocities at their intended release site. We divided 4-yr-old Hellbenders (n = 118) into six treatment groups to determine the effects of release season (fall or summer), release type (standard soft release or enhanced soft release), and conditioning (unconditioned or conditioned) on the number of days until first movement, release site retention, and survival. In November 2017, we released 80 radio-tagged individuals (40 conditioned and 40 unconditioned) into soft-release structures in the Blue River, Indiana. In July 2018, we released another 38 radio-tagged individuals (18 conditioned and 20 unconditioned) into soft-release structures at the same site. After release, we tracked each individual one to three times weekly for 10 mo (fall release) or 12 mo (summer release). We found that treatment groups released into caged cobble beds (i.e., enhanced soft release) delayed their first movement and had higher release site retention relative to groups released under caged shelter rocks (i.e., standard soft release). We found that conditioning had a positive effect on survival but only in the treatment group released in the summer. By combining techniques and releasing conditioned individuals in the summer using enhanced soft releases, we increased annual survival of captive-reared Hellbenders from a probability of 0.50 (95% confidence interval [CI] = 0.31–0.79) to 0.74 (95% CI = 0.55–0.99). Our results provide important information about techniques that can be adopted across captive-rearing programs to help maximize the conservation success of Eastern Hellbenders.

Research on anuran parasites often focuses on the description and identification of parasites and demonstrating that parasitic infection can have deleterious effects on the health of amphibians. There is comparatively little research on how parasitism influences evolutionary dynamics such as sexual selection. Here, we explore anuran blood parasites with a focus on parasite-mediated sexual selection. The Hamilton–Zuk hypothesis posits that parasite–host coevolution drives sexual ornamentation of hosts, and that the degree of ornament expression honestly signals heritable parasite resistance. Although the Hamilton–Zuk hypothesis has received support in a number of animal taxa, it has received little attention in amphibians. Neotropical Yellow Toads (Incilius luetkenii) are sexually dichromatic toads with an unusual sexual ornament: males turn from cryptic brown to bright lemon yellow for a very short period during the brief breeding season. In this study, we identify blood parasites in male Neotropical Yellow Toads, and we investigate one component of the Hamilton–Zuk hypothesis by comparing skin color and body condition to blood parasite levels. We found four types of parasites. Apicomplexa and frog erythrocytic virus were the most common, infecting 73% and 46% of toads, respectively, whereas Nematoda and bacteria were found in 27% and 36% of toads, respectively. We found negative relationships between parasites and male color: males infected with fewer Apicomplexa and Nematoda had higher yellow saturation, and males with fewer Nematoda had longer-wavelength hue. In contrast, we found one positive relationship between parasites and male color: males infected with higher levels of frog erythrocytic virus had higher brightness. Our results suggest that parasites may influence sexual traits in this species, but that the relationship is complex. This research contributes to our understanding of amphibian host–parasite coevolution by demonstrating a relationship between parasites and host coloration.

Detailed studies on the natural history of snakes are essential for ecological hypothesis-driven research and effective conservation. Herein, we studied the diet composition and morphology of Yucatecan Cantils (Agkistrodon russeolus Gloyd 1972 [Serpentes: Viperidae]), an understudied viperid species endemic to the Yucatán Peninsula. We collected data from live free-ranging snakes; freshly road-killed snakes and snakes deliberately killed by local villagers; and museum specimens and literature sources. We compared their age classes, sexes, and color morphs. Data came from snakes from Yucatán, Quintana Roo, and Campeche in Mexico, and two records were from northern Belize, comprising most of the species' distribution range. Examination of 76 individuals resulted in 77 prey items from 68 snakes. Results indicated that A. russeolus is a generalist-opportunistic predator that feeds on a wide variety of vertebrates, but primarily on lizards and small mammals and less frequently on birds, snakes, and anurans. Geographic patterns in the diet and morphology of A. russeolus were evident: snakes from the coastal region were smaller in body size and less heavy bodied and with a heavily lizard-based diet, whereas snakes from both dry and moist forest regions were larger and heavier and their diet was primarily mammal based. We did not detect differences in diet composition among age classes because lizards and mammals were eaten at all stages of life, but an “ontogenetic telescope” was evident; that is, the importance of mammals increases with snake body size and the spectrum of prey types consumed also broadens. Males had longer tails than females, and females were light colored more often than males, but other morphological characteristics were similar between the sexes. The sexes and color morphs did not differ in diet composition. We did not detect dietary composition variations between seasons, and our data indicate that this species can feed year-round opportunistically. Because of increasing environmental pressures within its range, studies are urgently needed to elucidate other critical aspects of the ecology of this viperid species.

Hyloxalus edwardsi and H. ruizi are high-Andean dendrobatid frogs that inhabit the Cordillera Oriental of Colombia. Both species were placed in the H. edwardsi group on the basis of the synapomorphic presence of an elongate cloacal sheath and the absence of a tarsal keel and vocal slits. The group was originally placed in Colostethus sensu lato and was subsequently transferred to Hyloxalus; however, no species of the group were included in previous phylogenetic analyses. Both species are critically endangered, and recent expeditions to their type localities have yielded no additional specimens. Nevertheless, on the western flank of the Cordillera Oriental of Colombia, we discovered a population possessing the elongate cloacal sheath but with other morphological character states that differentiate it from the previously known species. On the basis of this new material and examination of H. edwardsi, H. ruizi, and other Andean dendrobatids, we describe this population as a new species and test the phylogenetic position of this group. Our results corroborate the placement of this group within Hyloxalus, specifically as sister to H. picachos, thereby refuting the monophyly of the recently proposed H. subpunctatus clade. We also identify several new putative morphological synapomorphies of the H. edwardsi group related to the extrinsic cloacal musculature and the subarticular tubercles of the hand. Although the cloacal sheath character is still taxonomically useful, given the inherent difficulty in scoring it unambiguously on the basis of external morphology, we deprecate it for phylogenetic analysis in favor of the internal morphological characters.

Hyloxalus edwardsi e H. ruizi son dos dendrobátidos altoandinos que habitan la Cordillera Oriental de Colombia. Ambas especies hacen parte del grupo monofilético Hyloxalus edwardsi, puesto que comparten la presencia sinapomórfica de la proyección cloacal (o embudo cloacal, tubo cloacal), la ausencia de la quilla del tarso y de hendiduras vocales. Este grupo de especies fue ubicado dentro del género Colostethus sensu lato, y posteriormente fue transferido a Hyloxalus; sin embargo, ninguna de estas dos especies fue incluida en análisis filogenéticos anteriores. Ambas especies están en peligro crítico y en salidas de campo recientes a las localidades tipo no se encontraron registros adicionales. No obstante, sobre la vertiente occidental de la Cordillera Oriental de Colombia, descubrimos una población que presenta proyección cloacal y una quilla del tarso débil, pero con características morfológicas que diferencian esta población de las otras dos especies descritas del grupo H. edwardsi. Con base en este material y la revisión de H. edwardsi, H. ruizi, y de otros dendrobátidos de los Andes, describimos esta población como nueva especie, revisamos la proyección cloacal, reportamos la presencia de tubérculos hiperdistales en el dedo manual IV and V (nueva sinapomorfia putativa para el grupo H. edwardsi), y evaluamos la posición filogenética de este grupo por medio de la nueva especie. Los resultados corroboran que este grupo es parte de Hyloxalus, puesto que es la especie hermana de H. picachos, y también se refuta la monofilia del clado H. subpunctatus la cual fue recientemente propuesta. Además, también identificamos nuevos caracteres morfológicos, como por ejemplo series de transformaciones en la musculatura extrínseca de la cloaca y en los tubérculos subarticulares de los dedos manuales. A pesar que la “proyección cloacal” aún tiene utilidad taxonómica, este carácter es rechazado en inferencia filogenética, debido a su dificultad inherente para codificar sin ambigüedad a partir de la morfología externa y favorecemos sobre este los caracteres de morfología interna.

We describe Geophis berillus sp. nov., a new species of the Geophis sieboldi group based on three specimens from the Valle de Bravo region in the Trans-Mexican Volcanic Belt, Estado de México, Mexico. The new species differs from all other members of this group by having 17 dorsal scale rows without apical pits, 149 and 151–152 ventrals (in males and females, respectively), and the lower portion of each scale in the first dorsal scale row pale. The new species is allopatric respective to other Geophis species. A phylogenetic analysis based on mitochondrial DNA (cyt-b) supports the inclusion of G. berillus sp. nov. in the G. sieboldi group and a sister relationship with G. sieboldi, a finding corroborated by morphological evidence.

Describimos a Geophis berillus sp. nov una nueva especie del grupo Geophis sieboldi con base en tres especímenes de la región de Valle de Bravo en la Faja Volcánica Transmexicana. La nueva especie se diferencia de otros miembros del grupo por poseer 17 hileras de escamas dorsales sin fosas apicales, 149 y 152–153 ventrales (en machos y hembras, respectivamente) y la porción inferior de cada escama en la primera hilera de escamas dorsales clara. La nueva especie es alopátrica con respecto a otras especies de Geophis. Un análisis filogenético basado en DNA mitocondrial (cyt-b) respalda la inclusión de Geophis berillus sp. nov en el grupo G. sieboldi y su relación como grupo hermano de G. sieboldi, lo cual se corrobora con la evidencia morfológica.