Public databases in taxonomy, phylogenetics and geographic and fossil occurrence records are key research tools that provide raw materials, on which broad-scale analyses and synthesis in their ...respective fields are based. Comparable repositories for natural history observations are rare. Publicly available natural history data on traits like diet, habitat and reproduction are scattered across an extensive primary literature and remain relatively inaccessible to researchers interested in using these data for broad-scale analyses in macroecology and macroevolution. In this paper, I introduce SquamataBase, an open-source R package and database of predator-prey records involving the world's snakes. SquamataBase facilitates the discovery of natural history observations for use in comparative analyses and synthesis and, in its current form, contains observations of at least 18,304 predator individuals comprising 1,227 snake species and at least 58,633 prey items comprising 3,231 prey taxa. To facilitate integration with comparative analysis workflows, the data are distributed inside an R package, which also provides basic functionality for common data manipulation and filtering operations. Moving forward, the continued development of public natural history databases and their integration with existing digitisation efforts in biodiversity science should become a priority.
Some form of regeneration occurs in all lifeforms and extends from single-cell organisms to humans. The degree to which regenerative ability is distributed across different taxa, however, is harder ...to ascertain given the potential for phylogenetic constraint or inertia, and adaptive processes to shape this pattern. Here, we examine the phylogenetic history of regeneration in two groups where the trait has been well-studied: arthropods and reptiles. Because autotomy is often present alongside regeneration in these groups, we performed ancestral state reconstructions for both traits to more precisely assess the timing of their origins and the degree to which these traits coevolve. Using an ancestral trait reconstruction, we find that autotomy and regeneration were present at the base of the arthropod and reptile trees. We also find that when autotomy is lost it does not re-evolve easily. Lastly, we find that the distribution of regeneration is intimately connected to autotomy with the association being stronger in reptiles than in arthropods. Although these patterns suggest that decoupling autotomy and regeneration at a broad phylogenetic scale may be difficult, the available data provides useful insight into their entanglement. Ultimately, our reconstructions provide the important groundwork to explore how selection may have played a role during the loss of regeneration in specific lineages.
The effort to uncover herpetofauna within the zone of influence of the Sierra del Divisor National Park has been focused on the northern reaches. The Abujao basin represents the Sierra del Divisor ...region well in an understudied area central to the Peruvian Amazon. We found 108 species of amphibians and squamate reptiles. Seven records extend ranges from the northern regions, while two records unite with southern regions (Madre De Dios and the Fitzcarrald Arc/Purus valley). There are higher levels of diversity attributable to land-cover units indicative of high terraces and hilly zones, as opposed to low hydromorphic habitats. Our new record for
Pristimantis iiap
Padial, Gagliardi-Urrutia, Chaparro & Gutiérrez, 2016 brings more resolution to this newly described species. We made observations of an unidentified species of blindsnake, which could represent a unique part of the fauna. Despite variations, we only uphold the presence of various subspecies of
Micrurus annellatus
Peters, 1871.
AIM: Many ecological and evolutionary hypotheses have been proposed to explain latitudinal diversity gradients. However, any mechanistic explanation must include factors that change at least one of ...the three processes that can directly affect species richness: speciation, extinction and dispersal. I hypothesize that higher extinction in temperate areas, higher speciation in tropical areas and reduced dispersal into temperate regions drives latitudinal diversity gradients in squamates, and that these processes may be common in other groups. LOCATION: World‐wide. METHODS: I test for these processes using phylogenetic methods that can untangle speciation and extinction with respect to latitudinal position (GeoSSE), using a dated phylogeny containing c. 45% of all squamates (4161 species) with data on their geographic occurrence. RESULTS: I find that lineages in the tropics have high speciation and low extinction, but that temperate lineages have even higher speciation and extinction, leading to lower net diversification and higher turnover in temperate areas, with much higher rates of dispersal into the tropics from temperate areas than the reverse. MAIN CONCLUSIONS: Recent empirical studies using dated molecular phylogenies appear to be consistent in supporting a similar set of simple and intuitive results for processes driving latitudinal gradients in species richness: higher net diversification rates in the tropics, higher relative extinction fractions in temperate regions and reduced dispersal out of the tropics. I suggest that higher temperate extinction represents a dominant force for the origin and maintenance of latitudinal gradients, particularly in groups with ancient temperate clades.
The intensification of agriculture entails the simplification and homogenisation of the landscape, which has serious negative impacts on animal biodiversity. Herbaceous ground cover in olive groves ...creates heterogeneous patchworks that differ as regards how intensively farmed olive groves are structured and composed, which may lead to a decrease in this loss of biodiversity. Reptiles rapidly respond to changes in vegetation and other habitat disturbances, in spite of which, this taxa has received very little attention with regard to their vulnerability to agriculture systems. In this study, we investigated the response of a squamate reptile assemblage to different management systems in olive groves. Reptile communities were recorded in areas with three types of olive grove management systems: bare ground, natural cover crop, and monospecific cover crop. We further compared habitat structure and vegetation richness in the study area in order to verify if management systems have an impact on the frequency of occurrence and diversity of squamate reptiles species within olive groves. The community composition of reptiles differed among the three management systems, although this was modulated by the age of the olive trees. Our results show that the squamate reptile communities were more restricted in areas of intense management (bare ground) than in those with cover crops. When herbaceous covers existed, natural ground cover harboured a more diverse community. Our data suggest that while monospecific cover crops improve the frequency of occurrence of reptiles, species richness does not increase; however, more heterogeneous herbaceous ground cover (which, for instance, contain more species and are more similar to natural vegetation) would be a better solution regarding the promotion of diversity in reptile assemblages in agricultural landscapes. Finally our results may be used to improve the habitat quality of squamate reptile communities in similar woody crops like vineyards or orchards, where cover crops are beginning to be implemented.
We investigate local lizard richness and distribution in central Brazilian Cerrado, harbouring one of the least studied herpetofaunas in the Neotropical region. Our results are based on standardized ...samplings at 10 localities, involving 2917 captures of 57 lizard species in 10 families. Local richness values exceeded most presented in earlier studies and varied from 13 to 28 species, with modal values between 19 and 28 species. Most of the Cerrado lizard fauna is composed of habitat-specialists with patchy distributions in the mosaic of grasslands, savannas and forests, resulting in habitat-structured lizard assemblages. Faunal overlap between open and forested habitats is limited, and forested and open areas may act as mutual barriers to lizard distribution. Habitat use is influenced by niche conservatism in deep lineages, with iguanians and gekkotans showing higher use of forested habitats, whereas autarchoglossans are richer and more abundant in open habitats. Contrary to trends observed in Cerrado birds and large mammals, lizard richness is significantly higher in open, interfluvial habitats that dominate the Cerrado landscape. Between-localities variation in lizard richness seems tied to geographical distance, landscape history and phylogenetic constraints, factors operating in other well-studied lizard faunas in open environments. Higher richness in dominant, open interfluvial habitats may be recurrent in Squamata and other small-bodied vertebrates, posing a threat to conservation as these habitats are most vulnerable to the fast, widespread and ongoing process of habitat destruction in central Brazil.
Squamate embryos require weeks of high temperature to complete development, with the result that cool climatic areas are dominated by viviparous taxa (in which gravid females can sun‐bask to keep ...embryos warm) rather than oviparous taxa (which rely on warm soil to incubate their eggs). How, then, can some oviparous taxa reproduce successfully in cool climates – especially late in summer, when soil temperatures are falling? Near the northern limit of their distribution (in Sweden), sand lizards (Lacerta agilis) shift tactics seasonally, such that the eggs in late clutches complete development more quickly (when incubated at a standard temperature) than do those of early clutches. That acceleration is achieved by a reduction in egg size and by an increase in the duration of uterine retention of eggs (especially, after cool weather). Our results clarify the ability of oviparous reptiles to reproduce successfully in cool climates and suggest a novel advantage to reptilian viviparity in such conditions: by maintaining high body temperatures, viviparous females may escape the need to reduce offspring size in late‐season litters.
Aim To document geographical interspecific patterns of body size of European and North American squamate reptile assemblages and explore the relationship between body size patterns and environmental ...gradients. Location North America and western Europe. Methods We processed distribution maps for native species of squamate reptiles to document interspecific spatial variation of body size at a grain size of 110 x 110 km. We also examined seven environmental variables linked to four hypotheses possibly influencing body size gradients. We used simple and multiple regression, evaluated using information theory, to identify the set of models best supported by the data. Results Europe is characterized by clear latitudinal trends in body size, whereas geographical variation in body size in North America is complex. There is a consistent association of mean body size with measures of ambient energy in both regions, although lizards increase in size northwards whereas snakes show the opposite pattern. Our best models accounted for almost 60% of the variation in body size of lizards and snakes within Europe, but the proportions of variance explained in North America were less than 20%. Main conclusions Although body size influences the energy balance of thermoregulating ectotherms, inconsistent biogeographical patterns and contrasting associations with energy in lizards and snakes suggest that no single mechanism can explain variation of reptile body size in the northern temperate zone.
Vertebrate sex‐determining mechanisms (SDMs) are triggered by the genotype (GSD), by temperature (TSD), or occasionally, by both. The causes and consequences of SDM diversity remain enigmatic. Theory ...predicts SDM effects on species diversification, and life‐span effects on SDM evolutionary turnover. Yet, evidence is conflicting in clades with labile SDMs, such as reptiles. Here, we investigate whether SDM is associated with diversification in turtles and lizards, and whether alterative factors, such as lifespan's effect on transition rates, could explain the relative prevalence of SDMs in turtles and lizards (including and excluding snakes). We assembled a comprehensive dataset of SDM states for squamates and turtles and leveraged large phylogenies for these two groups. We found no evidence that SDMs affect turtle, squamate, or lizard diversification. However, SDM transition rates differ between groups. In lizards TSD‐to‐GSD surpass GSD‐to‐TSD transitions, explaining the predominance of GSD lizards in nature. SDM transitions are fewer in turtles and the rates are similar to each other (TSD‐to‐GSD equals GSD‐to‐TSD), which, coupled with TSD ancestry, could explain TSD's predominance in turtles. These contrasting patterns can be explained by differences in life history. Namely, our data support the notion that in general, shorter lizard lifespan renders TSD detrimental favoring GSD evolution in squamates, whereas turtle longevity permits TSD retention. Thus, based on the macro‐evolutionary evidence we uncovered, we hypothesize that turtles and lizards followed different evolutionary trajectories with respect to SDM, likely mediated by differences in lifespan. Combined, our findings revealed a complex evolutionary interplay between SDMs and life histories that warrants further research that should make use of expanded datasets on unexamined taxa to enable more conclusive analyses.
We investigate whether the mechanism of sex determination (SDM) is associated with diversification in turtles and lizards and whether lifespan's effect on transition rates explains the prevalence of temperature‐dependent sex determination (TSD) in turtles and genotypic sex determination (GSD) in lizards (including and excluding snakes), using a comprehensive dataset of SDM states for squamates and turtles, and leveraging large phylogenies for these two groups. We found no evidence that SDMs affect turtle or lizard diversification, but instead, that SDM transition rates differ between groups (in lizards, TSD‐to‐GSD transitions prevail and explain the predominance of GSD lizards; while in turtles, SDM transitions do not differ such that TSD predominance results from TSD retention). Based on the macro‐evolutionary evidence, we hypothesize that turtles and lizards followed different evolutionary trajectories with respect to SDM, likely mediated by differences in lifespan, as the generally shorter lizard lifespan renders TSD detrimental favoring GSD evolution in squamates, whereas turtle longevity permits the retention of an ancestral TSD state.
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