We provide a list of lizards, snakes, chelonians, and amphibians collected during a 30-day expedition to the Seridó Ecological Station (ESEC Seridó), Rio Grande do Norte state, Brazil. We sampled ...species using thirty-seven pitfall trap stations composed of four buckets each, along with glue traps and active searches. We recorded 13 species of lizards, eight snakes, 19 amphibians, and one chelonian. Rarefaction curves suggest local biodiversity is still underestimated. Sampling during rainy season was crucial to stabilize rarefaction curve for amphibians. Comparisons of our results with data from literature show we did not capture some arboreal and semifossorial lizards known for the area. Seridó Ecological Station fauna is characterized mainly by generalist species common to lowland Caatinga sites. Still, several Caatinga endemics species are found, which underscore the importance of this small but representative protected area.
AIM: To analyze impacts of habitat loss on evolutionary diversity and to test widely used biodiversity metrics as surrogates for phylogenetic diversity, we study spatial and taxonomic patterns of ...phylogenetic diversity in a wide‐ranging endemic Neotropical snake lineage. LOCATION: South America and the Antilles. METHODS: We updated distribution maps for 41 taxa, using species distribution models and a revised presence‐records database. We estimated evolutionary distinctiveness (ED) for each taxon using recent molecular and morphological phylogenies and weighted these values with two measures of extinction risk: percentages of habitat loss and IUCN threat status. We mapped phylogenetic diversity and richness levels and compared phylogenetic distances in pitviper subsets selected via endemism, richness, threat, habitat loss, biome type and the presence in biodiversity hotspots to values obtained in randomized assemblages. RESULTS: Evolutionary distinctiveness differed according to the phylogeny used, and conservation assessment ranks varied according to the chosen proxy of extinction risk. Two of the three main areas of high phylogenetic diversity were coincident with areas of high species richness. A third area was identified only by one phylogeny and was not a richness hotspot. Faunal assemblages identified by level of endemism, habitat loss, biome type or the presence in biodiversity hotspots captured phylogenetic diversity levels no better than random assemblages. Pitvipers found in the richest areas or included in the IUCN Red List showed significant phylogenetic clustering. MAIN CONCLUSIONS: Usual biodiversity metrics were unable to adequately represent spatial patterns of evolutionary diversity in pitvipers. Current Red List status fails to properly represent evolutionary distinctiveness in the group. Phylogenetic diversity is unevenly distributed even within biodiversity hotspots, and species‐poor areas may harbour high phylogenetic diversity. This reinforces the need for targeted and spatially accurate approaches for adequately representing evolutionary processes in conservation planning.
Satellite DNAs compose a large portion of all higher eukaryotic genomes. The turnover of these highly repetitive sequences is an important element in genome organization and evolution. However, ...information about the structure and dynamics of reptilian satellite DNA is still scarce. Two satellite DNA families, HindIII and TaqI, have been previously characterized in four species of the genus Iberolacerta. These families showed different chromosomal locations, abundances, and evolutionary rates. Here, we extend the study of both satellite DNAs (satDNAs) to the remaining Iberolacerta species, with the aim to investigate the patterns of variability and factors influencing the evolution of these repetitive sequences. Our results revealed disparate patterns but also common traits in the evolutionary histories of these satellite families: (i) each satellite DNA is made up of a library of monomer variants or subfamilies shared by related species; (ii) species-specific profiles of satellite repeats are shaped by expansions and/or contractions of different variants from the library; (iii) different turnover rates, even among closely related species, result in great differences in overall sequence homogeneity and in concerted or non-concerted evolution patterns, which may not reflect the phylogenetic relationships among taxa. Contrasting turnover rates are possibly related to genomic constraints such as karyotype architecture and the interspersed organization of diverging repeat variants in satellite arrays. Moreover, rapid changes in copy number, especially in the centromeric HindIII satDNA, may have been associated with chromosomal rearrangements and even contributed to speciation within Iberolacerta.
We analysed the diversification of squamate reptiles (7488 species) based on a new molecular phylogeny, and compared the results to similar estimates for passerine birds (5712 species). The number of ...species in each of 36 squamate lineages showed no evidence of phylogenetic conservatism. Compared with a random speciation–extinction process with parameters estimated from the size distribution of clades, the alethinophidian snakes (2600 species) were larger than expected and 13 clades, each having fewer than 20 species, were smaller than expected, indicating rate heterogeneity. From a lineage‐through‐time plot, we estimated that a provisional rate of lineage extinction (0.66 per Myr) was 94% of the rate of lineage splitting (0.70 per Myr). Diversification in squamate lineages was independent of their stem age, but strongly related to the area of the region within which they occur. Tropical vs. temperate latitude exerted a marginally significant influence on species richness. In comparison with passerine birds, squamates share several clade features, including: (1) independence of species richness and age; (2) lack of phylogenetic signal with respect to clade size; (3) general absence of exceptionally large clades; (4) over‐representation of small clades; (5) influence of region size on clade size; and (6) similar rates of speciation and extinction. The evidence for both groups suggests that clade size has achieved long‐term equilibrium, suggesting negative feedback of species richness on the rate of diversification.
Reproduction entails costs, and disentangling the relative importance of each stage of the reproductive cycle may be important to assess the costs and benefits of different reproductive strategies. ...We studied the early costs of reproduction in oviparous and viviparous lizard females of the bimodal reproductive species Zootoca vivipara. Egg retention time in oviparous females is approximately one‐third of the time in viviparous females. We compared the vitellogenesis and egg retention stages that are common to both reproductive modes. Precisely, we monitored the thermoregulatory behaviour, the weight gain and the immunocompetence of the females. Moreover, we injected an antigen in half of the females (immune challenge) to study the trade‐offs between reproductive mode and immune performance and between different components of the immune system. Finally, we experimentally induced parturition in viviparous females at the time of egg laying in oviparous females. Oviparous and viviparous females did not show strong differences in response to the immune challenge. However, viviparous females spent more time thermoregulating while partially hidden and gained more weight than oviparous females. The greater weight gain indicates that the initial period of egg retention is less costly for viviparous than for oviparous females or that viviparous females are able to save and accumulate energy at this period. This energy may be used by viviparous females to cope with the subsequent costs of the last two‐third of the gestation. Such an ability to compensate the higher costs of a longer egg retention period may account for the frequent evolution of viviparity in squamate reptiles.
Transition from a lizard-like to a snake-like body form is one of the most important transformations in reptilian evolution. The increasing number of sequenced reptilian genomes is enabling a deeper ...understanding of vertebrate evolution, although the genetic basis of the loss of limbs in reptiles remains enigmatic. Here we report genome sequencing, assembly, and annotation for the Asian glass lizard Ophisaurus gracilis, a limbless lizard species with an elongated snake-like body form. Addition of this species to the genome repository will provide an excellent resource for studying the genetic basis of limb loss and trunk elongation.
O. gracilis genome sequencing using the Illumina HiSeq2000 platform resulted in 274.20 Gbp of raw data that was filtered and assembled to a final size of 1.78 Gbp, comprising 6,717 scaffolds with N50 = 1.27 Mbp. Based on the k-mer estimated genome size of 1.71 Gbp, the assembly appears to be nearly 100% complete. A total of 19,513 protein-coding genes were predicted, and 884.06 Mbp of repeat sequences (approximately half of the genome) were annotated. The draft genome of O. gracilis has similar characteristics to both lizard and snake genomes.
We report the first genome of a lizard from the family Anguidae, O. gracilis. This supplements currently available genetic and genomic resources for amniote vertebrates, representing a major increase in comparative genome data available for squamate reptiles in particular.
Here we document the addition of thousands of potentially amplifiable microsatellite loci (PALs) and associated primer sequences for public use. We conducted whole-genome shotgun sequencing to obtain ...ultra-low coverage, random genomic sampling from ten African and Asian squamate reptile species (representing ten genera). We used unique genomic processing methods and generated PALs for the following species:
Acrochordus granulatus
,
Ahaetulla prasina
,
Cerberus rhynchops
,
Gonocephalus kuhlii
,
Ophiophagus hannah
,
Python bivittatus
,
Tribolonotus gracilis
,
Trimeresurus sabahi (Popeia sabahi)
,
Uromastyx geryi
and
Varanus exanthematicus
. All taxa included, as well as other related taxa not included in our study, are exploited heavily by the international skin and pet trades, yet researchers and conservation agencies currently lack substantial genetic resources for guiding conservation and management. Using stringent filtering methods, we generated between 467 and 8641 PALs for each of the ten species (52,164 PALs total), yielding a rich database of microsatellite loci and amplification primers for these taxa. In addition to the ten species targeted in our study, microsatellite markers provided in this database can likely be applied to a variety of closely related taxa that are also of conservation and commercial interest.
Skinks represent the most diversified squamate reptiles with a great variation in body size and form, and are found worldwide in a variety of habitats. Their remarkable diversification has been ...accompanied by only a few chromosome rearrangements, resulting in highly-conservative chromosomal complements of these lizards. In this study cross-species chromosome painting using Scincus scincus (2n = 32) as the source genome, was used to detect the chromosomal rearrangements and homologies between the following skinks: Chalcides chalcides (2n = 28), C. ocellatus (2n = 28), Eumeces schneideri (2n = 32), Lepidothyris fernandi (2n = 30), Mabuya quinquetaeniata (2n = 32). The results of this study confirmed a high degree of chromosome conservation between these species. The main rearrangements in the studied skinks involve chromosomes 3, 5, 6 and 7 of S. scincus. These subtelocentric chromosomes are homologous to the p and q arms of metacentric pair 3 and 4 in C. chalcides, C. ocellatus, L. fernandi, and M. quinquetaeniata, while they are entirely conserved in E. schneideri. Other rearrangements involve S. scincus 11 in L. fernandi and M. quinquetaeniata, supporting the monophyly of Lygosominae, and one of the chromosomes S. scincus 12-16, in M. quinquetaeniata. In conclusion, our data support the monophyly of Scincidae and confirm that Scincus-Eumeces plus Chalcides do not form a monophyletic clade, suggesting that the Scincus-Eumeces clade is basal to other members of this family. This study represents the first time the whole genome of any reptile species has been used for cross-species chromosome painting to assess chromosomal evolution in this group of vertebrates.
Snakes are renowned for their ability to subdue and swallow large, often dangerous prey animals. Numerous adaptations, including constriction, venom, and a strike-and-release feeding strategy, help ...them avoid injury during predatory encounters. Burton's legless lizard (Lialis burtonis Gray, Pygopodidae) has converged strongly on snakes. It is functionally limbless and feeds at infrequent intervals on relatively large prey items (other lizards) capable of inflicting a damaging bite. However, L. burtonis possesses neither venom glands, nor the ability to constrict prey. We investigated how L. burtonis subdues its prey without suffering serious retaliatory bites. Experiments showed that lizards modified their strike precision according to prey size; very large prey were always struck on the head or neck, preventing them from biting. In addition, L. burtonis delayed swallowing large lizards until they were incapacitated, whereas smaller prey were usually swallowed while still struggling. Lialis burtonis also displays morphological adaptations protecting it from prey retaliation. Its long snout prevents prey from biting, and it can retract its lidless eyes out of harm's way while holding onto a food item. The present study further clarifies the remarkable convergence between snakes and L. burtonis, and highlights the importance of prey retaliatory potential in predator evolution.
Most snakes and lizards produce eggs with flexible shells that interact with the environment to maintain water balance. Geckos produce rigid eggshells that are independent of an external source of ...water and can be oviposited in more open, dryer locations. In this study, we analyzed and compared the amino acid composition of 24 lizard species, six snake species, and four outgroups (including avian and reptilian elastin and chicken eggshell). Rigid Gecko eggshells had significantly lower levels of seven of the 17 amino acids evaluated. Multivariate analysis showed that proline was the most important amino acid in distinguishing between these two groups of eggshells, occurring at significantly higher levels in flexible eggshells. High levels of proline have also been observed in the eggshells of other species. Proline and other amino acids are associated with the alleviation of water and salt stress in plants.
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