Amphibia-Reptilia

Baffico, Gustavo; Úbeda, Carmen

doi: 10.1163/156853806777239986pmid: N/A

AbstractAlsodes gargola is an endemic species from northwest Patagonia, Argentina. Its tadpoles inhabit oligotrophic high altitude lakes and mountain streams from their sources. Tadpole diet is an important yet still unknown feature of its biology. This study analyzes alimentary tract content from A. gargola tadpoles collected from several of the species' typical habitats. For each group of items eaten, frequency of occurrence and its importance in the diet according to biovolume was calculated. Tadpole feeding behavior was also observed. The most common items were periphyton and plant material. The predominant algae were diatoms (typically periphytic), chlorophytes (periphytic and some planktonic) and a few cyanobacteria. Planktonic components were found in low proportion in all samples. The animal component (mainly from periphyton) was represented by ciliates, flagellates and amoebae, and varied according to the habitats, as did vascular plant fragments. There was a wide size range of ingested particles (from 10 to 400 μm) and a wide variety of components, according to the features of each habitat. These results suggest that tadpole of A. gargola are grazers of the periphytic community and detritus gatherers. The larval diet matches the tadpole's morphological and structural adaptations to a lotic-benthic habitat (depressed body, ventral subterminal oral disc capable of adherence, dorsal eyes, low, subparallel fins) and direct observation of behavior in natural environments (slow-swimming bottom-dwelling tadpoles in still water or streams with slow-flowing microhabitats). We discuss the ecological role of slow-developing tadpoles (regulation of periphyton development), which attain large biomass in their particular ecosystems, where they are the only aquatic vertebrates.

Mazerolle, Marc

doi: 10.1163/156853806777239922pmid: N/A

AbstractIn ecology, researchers frequently use observational studies to explain a given pattern, such as the number of individuals in a habitat patch, with a large number of explanatory (i.e., independent) variables. To elucidate such relationships, ecologists have long relied on hypothesis testing to include or exclude variables in regression models, although the conclusions often depend on the approach used (e.g., forward, backward, stepwise selection). Though better tools have surfaced in the mid 1970's, they are still underutilized in certain fields, particularly in herpetology. This is the case of the Akaike information criterion (AIC) which is remarkably superior in model selection (i.e., variable selection) than hypothesis-based approaches. It is simple to compute and easy to understand, but more importantly, for a given data set, it provides a measure of the strength of evidence for each model that represents a plausible biological hypothesis relative to the entire set of models considered. Using this approach, one can then compute a weighted average of the estimate and standard error for any given variable of interest across all the models considered. This procedure, termed model-averaging or multimodel inference, yields precise and robust estimates. In this paper, I illustrate the use of the AIC in model selection and inference, as well as the interpretation of results analysed in this framework with two real herpetological data sets. The AIC and measures derived from it is should be routinely adopted by herpetologists.

Busack, Stephen; Lawson, Robin

doi: 10.1163/156853806777239968pmid: N/A

AbstractPairwise sequence polymorphism in mitochondrial DNA and levels of differentiation among presumptive gene loci (expressed as Nei's Dˆ) tend to be greater between populations separated by the Strait of Gibraltar than between populations inhabiting either Morocco or Spain. Ancestral Psammodromus algirus inhabiting Iberia and North Africa while the Strait of Gibraltar was being formed and stabilized (Miocene-Pliocene) evolved in association with physiogeographic change brought about by this barrier to gene exchange. Considered in units of genetic change per kilometer, mtDNA differentiation is greater in Morocco than in Spain, and allozyme differentiation is slightly greater than, or equal to, that in Spain, suggesting that P. algirus has a longer and more complex history in Morocco than in Spain.

Fritz, Uwe; Petzold, Antje; Auer, Markus

doi: 10.1163/156853806777240029pmid: N/A

AbstractThirty-six complete skeletons, three shells, and x-rays of the extremities of 32 additional turtles of the Cuora galbinifrons complex have been compared with 38 other geoemydid species from 19 genera. Cuora bourreti differs from C. galbinifrons and C. picturata by a lost phalanx in the fourth finger and fourth toe. Individuals with a shell shape intermediate between C. bourreti and C. galbinifrons, as found on Hainan Island (China), have either the reduced phalangeal formula of C. bourreti (manus: 2-3-3-2-2, pes: 2-3-3-2-1) or the complete number of phalanges (manus: 2-3-3-3-2, pes: 2-3-3-3-1). Only in C. flavomarginata did we also register a lost phalanx in the fourth digit of manus and pes; in the pes of C. mouhotii the same character state may occur. In C. flavomarginata the fifth digit of the pes is also lacking. Some other terrestrial and semiterrestrial geoemydids (Cuora mccordi, Heosemys spinosa, and in part C. mouhotii and Leucocephalon yuwonoi) display a similar pattern of phalangeal reduction, resulting in the loss of the fifth digit of the pes. Likewise, in tortoises (Testudinidae), a further group of terrestrial chelonians, and the terrestrial turtle genus Terrapene (Emydidae) the loss of phalanges or complete digits is known to occur. Malayemys subtrijuga, Morenia petersi, Pangshura smithii and Siebenrockiella crassicollis differ from all other studied geoemydid taxa by an additional phalanx in the fifth digit of the manus (2-3-3-3-3); one P. smithii has on one body side three phalanges in the fifth digit of the pes (2-3-3-3-3). These are highly aquatic turtles with extensive toe webbing. Probably, longer digits (and thus a higher phalangeal number) are a favorable prerequisite for swimming while phalangeal loss seems to be the consequence of walking.Cuora bourreti and C. picturata have consistently in the bony carapace a very rare character state regarding the articulation of the rib tips with the peripheral plates. In both species the rib tips are intercalated between two peripheral plates in the bridge region. Intercalated rib tips like those in C. bourreti and C. picturata were found only in C. m. mouhotii, but not in the southern subspecies C. mouhotii obsti. In C. galbinifrons and all other geoemydid taxa studied the rib tips articulate on the bridge within the underlying peripheral and not between two peripherals. In turtles morphologically intermediate between C. bourreti and C. galbinifrons both characters states are found. This suggests that such individuals are hybrids or intergrades. Three known-locality specimens from Hainan Island display both extremes and an intermediate character state. This, together with external morphology and the occurrence of both phalangeal formulae in approximately the same frequency on that island, argues for genetic introgression of C. bourreti on the Hainan population of C. galbinifrons. We conclude that our findings qualify C. galbinifrons and C. bourreti under the Biological Species Concept as conspecific.

Andrade, Denis; Nascimento, Luciana; Abe, Augusto

doi: 10.1163/156853806777239995pmid: N/A

AbstractWe review the information currently available on the reproduction of the Amphisbaenia and provide original data on the reproductive biology of four Neotropical species: Amphisbaena alba; A. mertensi; Cercolophia roberti, and Leposternon infraorbitale. In total, we compiled data for 22 species: 17 Amphisbaenidae, 1 Rhineuridae, 3 Bipedidae, and 1 Trogonophidae. The majority of the species were oviparous with the exceptions of Loveridgea ionidesii, Monopeltis anchietae, M. capensis, and Trogonophis wiegmanni. Viviparity was interpreted as a derived trait that evolved independently for at least 3 times within the Amphisbaenia. In most species, reproduction is synchronized with the hot and rainy season and seems to vary with latitude. Although Amphisbaenia eggs have been found in ant nests, it remains disputable whether this is an obligatory or even a preferable location for egg-laying. Incubation time in A. mertensii lasts 59 days and this is the first report encompassing egg-laying to hatching for any Amphisbaenia species. Nonetheless, a two months incubation period seems to be the common rule for oviparous Amphisbaenia. The general pattern of reproductive output in Amphisbaenia is characterized by a low number of eggs/embryos per clutch whose individual size is comparatively large in relation to adult body size. Eggs are markedly elongated on the long axis and arranged in-line within the abdominal cavity possibly to prevent/diminish biomechanic drawbacks of egg bearing. Hatchlings of A. mertensi possess an egg-tooth implanted at the upper jaw, exhibit positive geotropism, and display defensive behaviors known to be present in adults. Our review shows that our current knowledge of Amphisbaenia reproduction is fragmentary, often based on the examination of small samples, and heavily dependent on the publication of anedoctal observations. Future publications on this subject are encouraged.

Brito, José; Santos, Xavier; Pleguezuelos, Juan; Fahd, Soumia; Llorente, Gustavo; Parellada, Xavier

doi: 10.1163/156853806777239940pmid: N/A

AbstractThe Lataste's viper Vipera latastei is a medium-sized viper distributed throughout almost the entire Iberian Peninsula and north-west of Africa. Former morphological studies noted the existence of two subspecies, V. l. gaditana and V. l. latastei, as well as a full species, V. monticola, in the High Atlas, corresponding to the prior overall range described for V. latastei. However, some results remained unclear in these former studies, e.g. the specific status of the Medium Atlas populations, the intra-subspecific differences in V. l. gaditana and, the true status of some isolated populations of the northern range. For this reason, 45 morphological characters were analysed in 672 preserved specimens covering the entire range. Categorical Principal Components Analysis (CATPCA) and Discriminant Function Analysis (DFA) were used to assess geographic variability, treating specimens individually or assigning them a priori to groups, respectively. Geographic groups were established according to the origin of specimens in isolated areas of mountain chains. As the percentage of correct assignment was low in DFA, initial groups were combined to maximize the percentage. The results from the multivariate analysis suggest morphological differentiation between populations. Some variables accounted for geographic variability: e.g. rows of dorsal scales at mid-body are taxonomically stable and clearly separate the African populations; and number of ventral scales showed a clinal variation from 126 to 143 ventrals in extreme populations. The three African groups manifested clear morphological differences, and especially specimens from the High Atlas (V. monticola) and Alger. On the contrary, a large number of initial Iberian groups were merged because of the low scores in the correct classification. The final groups showed a vast central area with low morphological differentiation as well as isolated populations in the NW, NE and SW Iberian Peninsula. This conclusion matches well with allopatric speciation processes during the Quaternary ice ages, which contributed to the contraction/expansion of range, isolation events, and peripheral population refugia. Morphological differentiation in external characters of V. latastei exhibited similar results with respect to V. aspis and V. ammodytes, the vipers occupying other southern European peninsulas. Molecular markers will contribute to elucidate the relationships between V. latastei populations and the history of colonisation across the Strait of Gibraltar.

Alcalde, Leandro; Blotto, Boris

doi: 10.1163/156853806777239959pmid: N/A

AbstractThe present paper provides original data on the chondrocranium, cranial muscles, oral disc and buccopharyngeal morphology of Limnomedusa macroglossa. We found that the cranial muscles and the buccopharyngeal papillation are not useful to relate Limnomedusa either to telmatobiine or leptodactyline genera. There are two chondrocranial characters (presence of a long processus pseudopterygoideus and sindesmotic connection of the partes alares and partes corpora of the cartilago suprarostralis) that relate Limnomedusa to the telmatobiine genera more than to any other genus within Leptodactylidae. Additionally, the processus pseudopterygoideus of Limnomedusa is fused to the basi cranii, a character state only known for some telmatobiine genera such as Alsodes and Telmatobius.

Luiselli, ; Akani, ; Bello, ; Angelici, ; Ude,

doi: 10.1163/156853806777239896pmid: N/A

AbstractHome range and nesting habitat were studied in two sympatric pelomedusid terrapins (Pelusios niger and Pelusios castaneus) from two study areas in the Niger Delta (Nigeria, West Africa), one with pristine habitat conditions and one which was polluted by a oil spill event some years before. Seventy-seven individuals (38 P. niger and 39 P. castaneus) were radiotracked, each for more than 60 days, and their home range was calculated by the minimum convex polygon method, with 95% of the point locations per individual. The mean home range size of females was significantly larger in the polluted area than in the pristine area in both P. niger and P. castaneus, and the mean home range size of female P. niger was significantly larger than that of female P. castaneus in the polluted area, but not in the pristine area. The mean home range size of males was significantly larger in the polluted area than in the pristine area in P. niger but not in P. castaneus, and the mean home range size of male P. niger was significantly larger than that of male P. castaneus in the polluted area but not in the pristine area. Radiotracked females of both species showed a clear preference for nesting sites situated along ponds and not along the banks of the river, on sandy soil, often with abundant vegetation around. Some females of both species deposited their eggs at greater distances from water bodies in the polluted area than in the pristine area. The comparative evidence of these patterns indicates consistent responses of the two species to the altered habitat, which further supports the general hypothesis that habitat pollution has seriously affected the ecological strategies of these terrapin species.

Logares, Ramiro; Úbeda, Carmen

doi: 10.1163/156853806777239913pmid: N/A

Kutrup, Bilal; Yilmaz, Nurhayat; Canakci, Sabriye; Belduz, Ali Osman; Doglio, Stefano

doi: 10.1163/156853806777239931pmid: N/A