A review of age estimation methods in non-avian reptiles by growth marks in hard tissues.

Age and growth-related data are basic biological parameters, essential in population ecology, evolution, and conservation biology. There is a growing body of published information on reptile demography derived from sclerochronology, a technique based on counting the growth layers deposited in bones (skeletochronology) and other hard body structures. Since the data are not always easily available, we compiled the existing published data, described the current status of knowledge, synthetized the conclusions of disparate studies, and identified patterns of research and information gaps, prioritizing the needs for future research. Our database includes the results of 468 published studies covering 236 reptile species from 41 families. These represent less than 2% of the total number of known extant species. Turtles and crocodiles are proportionally better studied, while snakes are the least examined group. The distribution of the research does not reflect conservation needs; we found an important geographic bias, with an overrepresentation of Northern temperate species. Only 23% of the studies checked the assumption of periodicity of growth marks deposition, and the method was found to be reliable or adequate in 79% of the cases. Overall, the data obtained through sclerochronology can be considered robust, especially if validation methods are employed, since the general goal is to characterize population parameters, trends, and dynamics, rather than determining the exact age of any specimen in particular.

Food and light availability induce plastic responses in fire salamander larvae from contrasting environments.

Phenotypic plasticity has been proposed as a mechanism facilitating the colonisation and adaptation to novel environments, such as caves. However, phenotypic plasticity in subterranean environments remains largely unexplored. Here, we test for plasticity in growth and development of fire salamander larvae (Salamandra salamandra) from subterranean and surface habitats, in response to contrasting food availability and light conditions. We hypothesized that: (i) low food availability and absence of light decrease larval growth and delay metamorphosis, (ii) light conditions mediate the effects of food availability on growth and time to metamorphosis, and (iii) larval response to contrasting light and food conditions is shaped by the habitat of origin. Our study showed that reduced food availability significantly delayed metamorphosis and slowed total length and body mass growth rates, while exposure to constant darkness slowed body mass growth rate. However, larvae slowed growth rates and increased time to metamorphosis without compromising size at metamorphosis. The effect of food availability on growth and time to metamorphosis did not change under different light conditions. Fire salamanders from subterranean and surface habitats responded differently only in relation to contrasting food availability conditions. Specifically, larvae from the surface habitat grew faster in high food conditions, while growth in larvae from the subterranean habitat was not influenced by food availability. Initial size also appeared to be an influential factor, since larger and heavier larvae grew slower, metamorphosed faster, and the size advantage was maintained in newly-metamorphosed juveniles. Overall, the results of our experiment suggest that plasticity and local adaptation favor the exploitation of aquatic subterranean habitats for breeding by fire salamanders, allowing successful development even under food shortage and day-length constraints, without compromising metamorphic size. Our findings have implications for conservation because they confirm that phenotypic plasticity plays a critical role in allowing fire salamanders to overcome altered environmental conditions.

A new glassfrog species of the genus Centrolene (Amphibia, Anura, Centrolenidae) from Cordillera del Cóndor, southern Ecuador.

Based on an integrative taxonomical approach, using molecular, morphological, and bioacoustics data, a new species of glassfrog of the genus Centrolene is described from Refugio de Vida Silvestre El Zarza, southern Ecuador. Centrolenezarzasp. nov. is a medium sized species, easily distinguished from all other glassfrogs by its unique combination of characters, such as a shagreen dorsum with elevated warts corresponding to white spots, an evident tympanum, half or more than half of the upper parietal peritoneum covered by iridophores, iridophores absent on all visceral peritonea, including the pericardium, a lobed liver lacking iridophores, males with small projecting humeral spines, the outer edges of forearms and tarsus with a row of enameled warts that often continue into the external edges of Finger IV and/or Toe V, and white or yellowish white iris with thick black reticulations. The new species is closely related to a currently undescribed species and superficially resembles C.condor, C.pipilata, C.solitaria, C.altitudinalis, and C.daidalea. The tadpole and advertisement and courtship calls are described, and the threats to the species survival, mainly represented by habitat loss and contamination due to mining activities, are briefly discussed.

ResumenSe describe una nueva especie de rana de cristal del género Centrolene, del Refugio de Vida Silvestre El Zarza, sur del Ecuador, basada en un enfoque de taxonomía integrativa, utilizando datos moleculares, morfológicos y bioacústicos. La especie Centrolenezarzasp. nov. es de tamaño mediano, que se distingue fácilmente de todas las demás ranas de cristal por su combinación única de caracteres tales como dorso de piel rugosa con verrugas elevadas que corresponden a manchas blancas, tímpano evidente, la mitad o más del peritoneo parietal superior cubierto por iridóforos, iridóforos ausentes en todos los peritoneos viscerales, incluido el pericardio, hígado lobulado sin iridóforos, machos con pequeñas espinas humerales salientes, borde externo de los antebrazos y el tarso con hilera de verrugas esmaltadas que a menudo continúan en los bordes externos del Dedo IV y/o del Dedo V del pie, e iris blanco o blanco amarillento con reticulaciones negras gruesas. La nueva especie está estrechamente relacionada con una especie no descrita y se parece superficialmente a C.condor, C.pipilata, C.solitaria, C.altitudinalis o C.daidalea. Se describen renacuajos, cantos de aviso y cortejo, y se discuten brevemente las amenazas para su supervivencia, representadas por la pérdida de hábitat y la contaminación debido a las actividades mineras.

Feeding ecology of the Terciopelo pit viper snake (Bothrops asper) in Ecuador.

Thoroughly documenting prey items and diet composition is crucial for understanding a predator's role in the ecosystem. In gape restricted predators, such as snakes, documenting and analyzing the type and size of the prey is important to interpret their ecological role. We describe the diet patterns of a species of venomous snake, the Terciopelo pit viper (Bothrops asper), from its Ecuadorian populations. Examining the gastrointestinal contents of museum specimens collected over an extensive area of the Pacific lowlands of Ecuador, we encountered 69 identifiable prey items from four major taxonomic groups (amphibians, centipedes, mammals, and reptiles). We evaluated the observed composition of prey to check for differences between sexes and size-classes. To complement our observations of the Terciopelo species complex throughout their distribution, we carried out a systematic literature review. Our data show an ontogenetic shift in diet, with a transition from more diverse diet in juveniles towards a mammal-specialized diet in adults, and distinct proportion of prey taxa between the sexes in the juvenile size class.

Amphibians of the equatorial seasonally dry forests of Ecuador and Peru.

Seasonally dry forests (SDFs) are one of the most challenging ecosystems for amphibians, fueling the diversity of this group of vertebrates. An updated inventory of native amphibians present in the Equatorial SDF is provided, which extends along the Pacific coast of Ecuador and northwestern Peru. The study is based on an extensive field sampling (two thirds of the total records) carried out throughout the Equatorial SDF, along with a compilation of the available information on distribution of amphibians in the region from published scientific papers, museum collections and on-line databases. The final dataset included 2,032 occurrence records for 30 amphibian species, belonging to eight anuran families. Additionally, data regarding conservation status, habitat use, spawn deposition site, reproductive mode, and body size, along with an identification key for all encountered species are provided. The results indicate a strong sampling bias with a deficit in the Peruvian part of the study area, and a need for urgent inventories targeted at under-sampled areas, using modern taxonomic methods. The study emphasizes the conservation priorities in the Equatorial SDF, based on the distribution, conservation status and life-history data. This information should be useful for the local authorities and institutions involved in the management and conservation of biodiversity in SDF.

Our unknown neighbor: A new species of rain frog of the genus Pristimantis (Amphibia: Anura: Strabomantidae) from the city of Loja, southern Ecuador.

We describe a new species of rain frog of the genus Pristimantis from the city of Loja, Southern Ecuador, based on an integrative taxonomy approach, combining molecular, morphological and bioacoustics data. Pristimantis lojanus sp. nov. is a medium sized species of the phylogenetically strongly supported P. phoxocephalus group, and its sister species is P. torresi. The new species can be easily distinguished from its closest congeners and morphologically similar species (that also have acuminate snout with a fleshy keel) by its characteristic advertisement call and morphological features (dorsum finely tuberculate with scattered larger tubercles, flanks without longitudinal lateral folds, no markings in axilla, groin or on concealed limb surfaces, and bronze iris). Additionally, we describe the advertisement call of its sister species, P. torresi. Finally, we detail the current situation of the amphibian species present in the city of Loja and its surroundings.

Age, size and body condition do not equally reflect population response to habitat change in the common spadefoot toad Pelobates fuscus.

Urbanization impacts biodiversity both directly through physical expansion over land, and indirectly due to land use conversion and human behaviors associated with urban areas. We assessed the response of a common spadefoot toad population (Pelobates fuscus) to habitat loss and fragmentation resulting from urban development by studying changes in size, body condition and age parameters. We compared samples collected in the early 2000s (sample A) and later on during 2012-2014 (sample B). The terrestrial habitats in the study area were severely reduced and fragmented due to the expansion of the human settlement. We found no significant differences in the age parameters between the two sampling periods; the median lifespan shortened from 3.5 (sample A) to 3.0 years (sample B), while the other age parameters were similar in both samples. In contrast, snout-vent length, body mass and body condition experienced a significant decrease over time. Our results suggest that changes in body size and body condition, rather than age parameters, better reflect the response of the common spadefoot toad population to declining habitat quality. Therefore, body measurements can provide reliable estimates of the impact of habitat degradation in amphibian populations.

Red List assessment of amphibian species of Ecuador: A multidimensional approach for their conservation.

Ecuador is one of the most biodiverse countries in the world, but faces severe pressures and threats to its natural ecosystems. Numerous species have declined and require to be objectively evaluated and quantified, as a step towards the development of conservation strategies. Herein, we present an updated National Red List Assessment for amphibian species of Ecuador, with one of the most detailed and complete coverages for any Ecuadorian taxonomic group to date. Based on standardized methodologies that integrate taxonomic work, spatial analyses, and ecological niche modeling, we assessed the extinction risk and identified the main threats for all Ecuadorian native amphibians (635 species), using the IUCN Red List Categories and Criteria. Our evaluation reveals that 57% (363 species) are categorized as Threatened, 12% (78 species) as Near Threatened, 4% (26 species) as Data Deficient, and 27% (168 species) as Least Concern. Our assessment almost doubles the number of threatened species in comparison with previous evaluations. In addition to habitat loss, the expansion of the agricultural/cattle raising frontier and other anthropogenic threats (roads, human settlements, and mining/oil activities) amplify the incidence of other pressures as relevant predictors of ecological integrity. Potential synergic effects with climate change and emergent diseases (apparently responsible for the sudden declines), had particular importance amongst the threats sustained by Ecuadorian amphibians. Most threatened species are distributed in montane forests and paramo habitats of the Andes, with nearly 10% of them occurring outside the National System of Protected Areas of the Ecuadorian government. Based on our results, we recommend the following actions: (i) An increase of the National System of Protected Areas to include threatened species. (ii) Supporting the ex/in-situ conservation programs to protect species considered like Critically Endangered and Endangered. (iii) Focalizing research efforts towards the description of new species, as well as species currently categorized as Data Deficient (DD) that may turn out to be threatened. The implementation of the described actions is challenging, but urgent, given the current conservation crisis faced by amphibians.

Fifty years after: A taxonomic revision of the amphibian species from the Ecuadorian biodiversity hotspot Abra de Zamora, with description of two new Pristimantis species.

Abra de Zamora is an important biodiversity hotspot in southern Ecuador. Between 1938 and 2010, eleven species of frogs were described from here: Lynchius flavomaculatus, Gastrotheca psychrophila, Pristimantis balionotus, P. colodactylus, P. cryptomelas, P. percultus, P. versicolor, P. vidua, Telmatobius cirrhacelis, P. andinognomus, and Atelopus podocarpus. Unfortunately, many of these species were not re-encountered after their original description, and for the majority DNA samples were not available, making their phylogenetic position unknown. In this study, we assess the current state of the amphibians from Abra de Zamora, by: i. redescribing the species which were first reported from the area, by contributing genetic delimitation (for L. flavomaculatus, P. balionotus, P. colodactylus, P. percultus, and P. vidua), release call (L. flavomaculatus) and advertisement call descriptions (for P. balionotus, P. vidua and P. versicolor); ii. presenting an updated amphibian species list of Abra de Zamora, with the description of two additional Pristimantis species; iii. updating the distribution of these species, including data collected in similar montane habitats from surrounding areas; and iv. amending recommendations regarding their conservation status.

Adult-Juvenile interactions and temporal niche partitioning between life-stages in a tropical amphibian.

Divergence in ecological niche offers organisms the opportunity of exploiting different food and habitat resources, scaling down competition and predation both among species, and within different age or size-classes of the same species. In harsh environments, where abiotic factors determine a clustering of resources during short timespans, competition and predation between organisms is likely to be enhanced. This is the case in tropical dry forests, where amphibians have limited opportunities to feed, their activity being restricted to the short rainy season. One way to maximize resource exploitation while avoiding predation risk is by adopting different diel activity patterns. We tested this hypothesis by comparing activity patterns in adults and recently metamorphosed juveniles of Pacific horned frogs (Ceratophrys stolzmanni) during field surveys and in an experimental study. Field surveys showed that the adults are strictly nocturnal, whereas freshly metamorphosed juveniles can be found active above ground at all hours, with a peak activity during daytime. The average body condition index of juveniles found active during the night was higher than that of juveniles found active during the day, suggesting that the weaker individuals may be constrained to being active during the day. On the other hand, in a laboratory experiment, juveniles that were visually exposed to adults moved less than those in the absence of adults. Both field and experimental observations indicate a temporal niche divergence between life stages. The results of the experiment offer support to the hypothesis that the juveniles in this species display an inverse activity pattern compared to adults, which can reduce competitive interactions and predation pressure from the larger conspecifics.

How to recover from a bad start: size at metamorphosis affects growth and survival in a tropical amphibian.

BACKGROUND: In species with complex life cycles, size at metamorphosis is a key life-history trait which reflects the complex interactions between costs and benefits of life in the aquatic and terrestrial environments. Whereas the effects of a deteriorating larval habitat (e.g. pond desiccation) on triggering an early metamorphosis have been extensively investigated in amphibians, the consequences of the resulting reduced size at metamorphosis on fitness in the post-metamorphic terrestrial stage remain poorly understood. We tested the hypothesis that a smaller size at metamorphosis negatively affects performance and survival in the ensuing terrestrial stage. Using as model a tropical amphibian (Ceratophrys stolzmanni) showing a large phenotypic plasticity in metamorphosing traits, we evaluated the effects of size at metamorphosis on fitness-related trophic and locomotor performance traits, as well as on growth and survival rates. RESULTS: Our results support the hypothesis that a larger size at metamorphosis is correlated with better survival and performance. The survival rate of large metamorphosing individuals was 95%, compared to 60% for those completing metamorphosis at a small size. Locomotor performance and gape size were positively correlated with body size, larger animals being more mobile and capable to ingest larger prey. However, smaller individuals achieved higher growth rates, thus reducing the size gap. CONCLUSIONS: Overall, size at metamorphosis affected profoundly the chances of survival in the short term, but smaller surviving individuals partly compensated their initial disadvantages by increasing growth rates.

Genetic delimitation of Pristimantisorestes (Lynch, 1979) and P.saturninoi Brito et al., 2017 and description of two new terrestrial frogs from the Pristimantisorestes species group (Anura, Strabomantidae).

In the genus Pristimantis, species are often combined into taxonomic units called species groups. The taxonomy of these groups is frequently inaccurate due to the absence of genetic data from type series and repeated misidentifications generated by high morphological resemblance between taxa. Here, we focus on the P.orestes species group, providing the first genetic assessment of P.orestes sensu stricto from individuals collected from the type locality, with a reviewed diagnosis and description of advertisement calls. We find that two lineages previously named P.orestes are genetically distinct and should be separated into two different species. Based on genetic and morphological data, we name one of these species P.cajanuma sp. nov. This new species is morphologically distinct from other members of the group by having shagreen dorsal skin, evident dorsolateral folds, broader discs on toes and fingers and pale gray ventral coloration. Additionally, P.saturninoi is placed within the P.orestes species group based on genetic data from its type series. However, we find that one of its paratypes is genetically distinct and belongs to a clade containing a new species we name P.quintanai sp. nov. This new species is morphologically distinguished by lacking a tympanic membrane and vocal sacs in males, and by having expanded discs on toes and fingers, finely tuberculated dorsal skin and irregular white or cream spots in the groin and concealed surfaces of thighs. Our findings highlight the importance of providing genetic characterization and placement from the type series in taxonomic challenging groups, such as Pristimantis. We also suggest that the diversity of species within the P.orestes group will increase as more sampling is achieved in the southern Andes of Ecuador.

ResumenLas especies pertenecientes al género Pristimantis usualmente están agrupadas en unidades taxonómicas llamadas grupos de especies. A menudo la taxonomía de estos grupos es problemática debido a la ausencia de información genética de las series tipo de las especies o debido a identificaciones erróneas generadas por la elevada similitud morfológica entre especies. Aquí nos enfocamos en el grupo de especies P.orestes y proveemos la primera evaluación genética de P.orestes sensu stricto en base a individuos colectados en la localidad tipo de la especie con una diagnosis revisada y descripción de vocalizaciones. Encontramos que dos linajes previamente nombrados como P.orestes son genéticamente distintos y deberían ser considerados como dos distintas especies. En base a evidencia genética y morfológica nombramos a una de estas especies P.cajanuma sp. nov. La nueva especie es distinta de otras especies del grupo por presentar piel dorsal con textura finamente granular, pliegues dorsolaterales evidentes, discos amplios en dedos de pie y manos y una coloración ventral gris pálido. Adicionalmente, P.saturninoi es colocada dentro del grupo de especies P.orestes en base a información genética de especímenes tipo. Sin embargo, encontramos que uno de los paratipos es genéticamente distinto y está dentro de un clado que incluye a una nueva especie morfológicamente similar que nombramos como P.quintanai sp. nov. Esta nueva especie se distingue de otros Pristimantis del grupo por carecer de una membrana timpánica diferenciada, machos sin sacos vocales y por presentar discos expandidos en los dedos de pies y manos, una piel dorsal con textura finamente tubercular y manchas irregulares blancas o crema-blanquecinas en las ingles y superficies ocultas de los muslos. Nuestros resultados resaltan la importancia de proveer caracterizaciones genéticas de especímenes tipos en grupos taxonómicamente complejos como los Pristimantis. Sugerimos que la diversidad de especies dentro del grupo de especies P.orestes incrementara a medida que más expediciones de campo se realicen en el sur de los Andes de Ecuador.

What does a Pacman eat? Macrophagy and necrophagy in a generalist predator (Ceratophrys stolzmanni).

We describe for the first time the feeding ecology of the Pacific horned frog (Ceratophrys stolzmanni), as inferred through gastrointestinal tract content analysis and behavioural observations in its natural habitat. Ingested prey in adults ranged from mites and various insects to frogs and snakes. Prey items predominantly consisted of gastropods, non-formicid hymenopterans, and centipedes. We found no relationship between the size of the predator and the prey ingested, in terms of prey size, volume or number of items ingested. Additional direct observations indicate that all post-metamorphic stages are voracious, preying on vertebrates and engaging in anurophagy, cannibalism, and even necrophagy. Our study sheds light on the feeding habits of one of the least known species of horned frog.

A new minute Pristimantis (Amphibia: Anura: Strabomantidae) from the Andes of southern Ecuador.

We describe a new rainfrog species (Pristimantis), from the wetland complex Oña, Nabón, Saraguro and Yacuambi, in the Andes of southern Ecuador, at altitudes ranging between 3000-3400 m a.s.l. Pristimantis tiktik sp. nov. is a small frog, displaying sexual dimorphism (the males with dorsum of various shades of gray, brown, orange or green and a whitish or pinkish yellow venter; females with brownish gray or gray dorsum and a reticulated white and black venter), with SVL ranging between 19.7-20.4 mm in females (n = 3) and 16.1-18.4 mm in males (n = 6). The skin on dorsum is tuberculated, that on venter is coarsely areolate, dorsolateral folds are absent, tympanic membrane is absent but the tympanic annulus is evident, cranial crests are absent, discs on fingers just slightly expanded, heel is lacking enlarged tubercles, inner edge of tarsus is bearing a long fold, Toe V is slightly longer than Toe III and the iris coloration is bronze with fine black reticulations. The males have a large subgular vocal sac that extends onto the chest and vocal slits but lack nuptial pads. The unique advertisement call consists of long duration series of periodically repeated clicks: "tik". Molecular analyses place the new species in the recently resurrected P. orestes group, as the sister species of the assemblage that contains P. bambu, P. mazar, P. simonbolivari and an undescribed species.

Out of the ground: two coexisting fossorial toad species differ in their emergence and movement patterns.

Understanding the way species with similar niches can coexist is a challenge in ecology. The niche partitioning hypothesis has received much support, positing that species can exploit available resources in different ways. In the case of secretive species, behavioural mechanisms of partitioning are still poorly understood. This is especially true for fossorial frogs because individuals hide underground by day and are active only during the night. We investigated the nocturnal activity and tested the niche partitioning hypothesis in two syntopic fossorial spadefoot toads (Pelobates fuscus and Pelobates syriacus) by examining interspecific variation in emergence from the soil. We employed a night vision recording system combined with video tracking analyses in a replicated laboratory setting to quantify individual movement patterns, a procedure that has not been used until now to observe terrestrial amphibians. Most individuals appeared on the surface every night and returned to their original burrow (about 60% of the times), or dug a new one around morning. There was a large temporal overlap between the two species. However, P. syriacus was significantly more active than P. fuscus in terms of total distance covered and time spent moving, while P. fuscus individuals left their underground burrow more frequently than P. syriacus. Consequently, P. fuscus adopted more of a sit-and-wait behaviour compared to P. syriacus, and this could facilitate their coexistence. The use of night video tracking technologies offered the advantage of individually tracking these secretive organisms during their nocturnal activity period and getting fine-grained data to understand their movement patterns.

A new species of Pristimantis from southern Ecuador (Anura, Craugastoridae).

A new species of Pristimantis is described from Reserva Buenaventura, southern Ecuador, at elevations between 878 and 1082 m. A molecular phylogeny based on nuclear and mitochondrial genes shows that the new species is closely related to Pristimantis phoxocephalus, Pristimantis riveti, and Pristimantis versicolor. The new species differs from them and other morphologically similar congeners in having a low W-shaped dermal ridge in the scapular region, a large conical tubercle on the upper eyelid and on the heel, a thin mid dorsal fold, and a longitudinal lateral fold starting behind the tympanic fold and extending along the anterior two thirds of the flank. The new species inhabits cloud forests in the Pacific slopes of the Andes.

ResumenDescribimos una nueva especie de Pristimantis de la Reserva Buenaventura, al sur del Ecuador, entre elevaciones de 878 y 1082 m. Una filogenia molecular basada en genes nucleares y mitocondriales revela que la nueva especie está cercanamente relacionada a Pristimantis phoxocephalus, Pristimantis riveti y Pristimantis versicolor. La nueva especie difiere de ellas y otros congéneres morfológicamente similares por presentar un pliegue bajo en forma de "W" en la región escapular, un tubérculo cónico sobre el párpado y en el talón, un delgado pliegue mediodorsal y un pliegue lateral longitudinal que se inicia detrás del pliegue timpánico y se extiende a lo largo de dos tercios del flanco. La nueva especie vive en bosques nublados de las estribaciones pacíficas de los Andes.

Diversity and distribution of reptiles in Romania.

The reptile fauna of Romania comprises 23 species, out of which 12 species reach here the limit of their geographic range. We compiled and updated a national database of the reptile species occurrences from a variety of sources including our own field surveys, personal communication from specialists, museum collections and the scientific literature. The occurrence records were georeferenced and stored in a geodatabase for additional analysis of their spatial patterns. The spatial analysis revealed a biased sampling effort concentrated in various protected areas, and deficient in the vast agricultural areas of the southern part of Romania. The patterns of species richness showed a higher number of species in the warmer and drier regions, and a relatively low number of species in the rest of the country. Our database provides a starting point for further analyses, and represents a reliable tool for drafting conservation plans.