Omar Torres-Carvajal

Early bursts of body size and shape evolution are rare in comparative data.

George Gaylord Simpson famously postulated that much of lifes diversity originated as adaptive radiations—more or less simultaneous divergences of numerous lines from a single ancestral adaptive type. However, identifying adaptive radiations has proven difficult due to a lack of broad‐scale comparative datasets. Here, we use phylogenetic comparative data on body size and shape in a diversity of animal clades to test a key model of adaptive radiation, in which initially rapid morphological evolution is followed by relative stasis. We compared the fit of this model to both single selective peak and random walk models. We found little support for the early‐burst model of adaptive radiation, whereas both other models, particularly that of selective peaks, were commonly supported. In addition, we found that the net rate of morphological evolution varied inversely with clade age. The youngest clades appear to evolve most rapidly because long‐term change typically does not attain the amount of divergence predicted from rates measured over short time scales. Across our entire analysis, the dominant pattern was one of constraints shaping evolution continually through time rather than rapid evolution followed by stasis. We suggest that the classical model of adaptive radiation, where morphological evolution is initially rapid and slows through time, may be rare in comparative data.

The global distribution of tetrapods reveals a need for targeted reptile conservation

The distributions of amphibians, birds and mammals have underpinned global and local conservation priorities, and have been fundamental to our understanding of the determinants of global biodiversity. In contrast, the global distributions of reptiles, representing a third of terrestrial vertebrate diversity, have been unavailable. This prevented the incorporation of reptiles into conservation planning and biased our understanding of the underlying processes governing global vertebrate biodiversity. Here, we present and analyse the global distribution of 10,064 reptile species (99% of extant terrestrial species). We show that richness patterns of the other three tetrapod classes are good spatial surrogates for species richness of all reptiles combined and of snakes, but characterize diversity patterns of lizards and turtles poorly. Hotspots of total and endemic lizard richness overlap very little with those of other taxa. Moreover, existing protected areas, sites of biodiversity significance and global conservation schemes represent birds and mammals better than reptiles. We show that additional conservation actions are needed to effectively protect reptiles, particularly lizards and turtles. Adding reptile knowledge to a global complementarity conservation priority scheme identifies many locations that consequently become important. Notably, investing resources in some of the world’s arid, grassland and savannah habitats might be necessary to represent all terrestrial vertebrates efficiently.The global distribution of nearly all extant reptile species reveals richness patterns that differ spatially from that of other taxa. Conservation prioritization should specifically consider reptile distributions, particularly lizards and turtles.

Phylogeny and biogeography of the most diverse clade of South American gymnophthalmid lizards (Squamata, Gymnophthalmidae, Cercosaurinae).

Nearly 50% of the diversity of the speciose Neotropical lizard clade Gymnophthalmidae is nested within the subclade Cercosaurinae. The taxonomy of Cercosaurinae lizards has been historically confusing because many diagnostic characters of those clades traditionally ranked as genera do not represent true diagnostic apomorphies. Even though molecular phylogenies of several genera have been presented in the last few years, some of them remain poorly sampled (e.g., Anadia, Echinosaura, Potamites, Riama). In this paper we present a more comprehensive phylogeny of Cercosaurinae lizards with emphasis on Andean taxa from Ecuador and Peru, as well as a time-calibrated phylogeny with reconstruction of ancestral areas. Our analysis includes 52% of all recognized species of Cercosaurinae (67 species) and 1914 characters including three mitochondrial and one nuclear gene. We find that Anadia, Echinosaura, Euspondylus, Potamites, Proctoporus, and Riama are not monophyletic: the Tepuian Anadia mcdiarmidi is not sister to Andean species of Anadia; Echinosaura sulcarostrum is not included in the same clade formed by other species of Echinosaura and their more recent common ancestor; Teuchocercus is nested within Echinosaura; species of Euspondylus included in this study are nested within Proctoporus; Riama laudahnae is included in Proctoporus; and Potamites is paraphyletic and split in two separate clades, one of which we name Gelanesaurus, also a new genus-group name. Within Potamites, P. ecpleopus is paraphyletic, and P. strangulatus strangulatus and P. strangulatus trachodus are recognized as two distinct species. We also identify three unnamed clades (i.e., not nested within any of the recognized genera) from Andean populations in Ecuador and Peru. The estimated age of the clade Cercosaurinae (∼60Ma) corresponds to the early stages of the northern Andes. Even though the distribution of the most recent common ancestor of Cercosaurinae remains equivocal, our analysis shows that these lizards colonized and radiated along the northern Andes before reaching the central Andes in Peru. Finally, we present phylogenetic definitions for some of the recovered clades to promote a clear and precise classification of Cercosaurinae lizards.

Phylogeny of Neotropical Cercosaura (Squamata: Gymnophthalmidae) lizards☆

Among Neotropical lizards, the geographically widespread gymnophthalmid Cercosaura as currently defined includes lowland and highland taxa from Panama to Argentina, with some species occurring in the northern Andes. In this study we analyze three mitochondrial (12S, 16S, ND4) and one nuclear (c-mos) gene using Bayesian methods to clarify the phylogenetic relationships among most species of Cercosaura based on a well-supported phylogenetic hypothesis that also includes a large sample of other taxa within Cercosaurini. The phylogenetic tree obtained in this paper shows that Cercosaura as currently defined is not monophyletic. Two species from the northern Andes (C. dicra and C. vertebralis) are nested within Pholidobolus, which has been formerly recognized as a major radiation along the Andes of Ecuador and Colombia. Therefore, Cercosaura has probably not diversified in the northern Andes, although the phylogenetic position of C. hypnoides from the Andes of Colombia remains unknown. Tree topology and genetic distances support both recognition of C. ocellata bassleri as a distinct species, C. bassleri, and recognition of C. argula and C. oshaughnessyi as two different species. In the interest of promoting clarity and precision regarding the names of clades of gymnophthalmid lizards, we propose a phylogenetic definition of Cercosaura.

A new species of Riama Gray, 1858 (Squamata: Gymnophthalmidae) from the Tropical Andes

A new species of Riama lizard from the western slopes of the Andes in northern Ecuador is described herein. Morphologically, Riama yumborum sp. nov. can be distinguished from all other congenerics by having an incomplete nasoloreal suture and a cylindrical hemipenial body with diagonally orientated flounces on its lateral aspect. Phylogenetic analyses of mitochondrial and nuclear DNA support the monophyly of the new species and its sister taxon relationship with R. labionis, which occurs allopatrically.

Evolutionary history of Andean Pholidobolus and Macropholidus (Squamata: Gymnophthalmidae) lizards

Andean Pholidobolus and Macropholidus lizards contain seven and two species, respectively, as currently recognized. We analyze three mitochondrial loci (12S, 16S, ND4) using Bayesian methods to clarify the phylogenetic relationships between these genera based on a well-supported phylogenetic hypothesis. The phylogenetic tree obtained in this paper includes two main clades and shows that both Pholidobolus and Macropholidus are not monophyletic. A chronophylogenetic analysis indicates that the southernmost clade, occurring in the Huancabamba Depression, diversified earlier than the northern-Andes clade. Bayesian hypothesis tests reject previous phylogenetic hypotheses. We propose phylogenetic definitions for the main clades inferred herein.

Notes on the Natural History of the Little-Known Ecuadorian Horned Anole, Anolis proboscis

Abstract Until very recently, the horned anole of Ecuador, Anolis proboscis, was known from only six male specimens, the last collected in 1966. The species was rediscovered in 2005 and in subsequent years additional specimens have been collected in the general vicinity of the type locality. These include several females, which lack the conspicuous rostral appendage seen in males. Despite rediscovery, the natural history of this enigmatic anole remains almost completely unknown. We conducted an ecological and behavioral study of this species near Mindo, Ecuador. Anolis proboscis is an extremely slow-moving and cryptic species that often occurs high in the trees. The rostral horn notwithstanding, A. proboscis is indistinguishable from Greater Antillean anoles of the “twig” ecomorph class in morphology, ecology, and behavior. The possession of a horn only by males suggests a role in sexual selection. We found the horn in life to be soft and highly flexible and thus unsuitable for use as a weapon in male–male combat; hence, the horn most likely serves as a signal and may be involved in mate choice or territorial displays. However, we did not observe any social encounters during our observations and are thus unable to test these hypotheses. Given its cryptic morphology and behavior, it is not surprising that A. proboscis is so rarely observed.

Priority areas for biodiversity conservation in mainland Ecuador

Ecuador’s territory harbors a unique set of species and ecosystems, many of them endemic to the countries’ territory and subject to different sources of threat of anthropogenic origin. Despite national and subnational conservation strategies developed in Ecuador to conserve its biodiversity in the long run, including the National System of Protected Areas (PANE) and the forest conservation incentive program SocioBosque (PSB), further actions are needed to mitigate and reverse the effects of threats for the persistence of biodiversity. This study was designed to identify the most important areas for biodiversity conservation in mainland Ecuador that can contribute to preserving key species (i.e. endemic, threatened) and ecosystems in the wider landscape, thus complementing current conservation efforts (i.e. PANE). Species distribution models and recent maps were used to identify a set of 744 species and 87 ecosystems as surrogates of the country’s biodiversity. Marxan, a systematic reserve selection algorithm was used to identify important biodiversity areas that could represent between 10% and 20% of the remnant distribution of the surrogates. The optimized solution generated by Marxan included 24% (3.64 million ha) of Ecuador′s remnant vegetation, of which 35% is within the current national protected area system and 13% (456 000 ha) are included within SocioBosque communal and private conservation agreements. Major conservation shortfalls of the PANE were concentrated in the Southern Andes, Central Amazonia, and the Central and Southern portions of the Coastal plain. The incidence of complementary criteria to prioritize conservation strategies, related to climate change, ecosystem conversion, carbon and accessibility, and population density change in relation to the important biodiversity areas was heterogeneous among regions. This confirms the need to implement differentiated conservation and sustainable landscape management strategies. Fourteen priority landscapes were identified based on these important biodiversity areas, including remnant ecosystems considered critical for maintaining large-scale connectivity among regions and preservation of restricted range and threatened species. Further work is needed to expand base information about distribution patterns of biodiversity, improve the representation of endemic and threatened species in conservation strategies, and to fully integrate conservation priorities among a wider set of goals in land use planning exercises at different scales.

Independent Demographic Responses to Climate Change among Temperate and Tropical Milksnakes (Colubridae: Genus Lampropeltis )

The effects of Late Quaternary climate change have been examined for many temperate New World taxa, but the impact of Pleistocene glacial cycles on Neotropical taxa is less well understood, specifically with respect to changes in population demography. Here, we examine historical demographic trends for six species of milksnake with representatives in both the temperate and tropical Americas to determine if species share responses to climate change as a taxon or by area (i.e., temperate versus tropical environments). Using a multilocus dataset, we test for the demographic signature of population expansion and decline using non-genealogical summary statistics, as well as coalescent-based methods. In addition, we determine whether range sizes are correlated with effective population sizes for milksnakes. Results indicate that there are no identifiable trends with respect to demographic response based on location, and that species responded to changing climates independently, with tropical taxa showing greater instability. There is also no correlation between range size and effective population size, with the largest population size belonging to the species with the smallest geographic distribution. Our study highlights the importance of not generalizing the demographic histories of taxa by region and further illustrates that the New World tropics may not have been a stable refuge during the Pleistocene.

Cost-effectiveness of using small vertebrates as indicators of disturbance

In species-rich tropical forests, effective biodiversity management demands measures of progress, yet budgetary limitations typically constrain capacity of decision makers to assess response of biological communities to habitat change. One approach is to identify ecological-disturbance indicator species (EDIS) whose monitoring is also monetarily cost-effective. These species can be identified by determining individual species responses to disturbance across a gradient; however, such responses may be confounded by factors other than disturbance. For example, in mountain environments the effects of anthropogenic habitat alteration are commonly confounded by elevation. EDIS have been identified with the indicator value (IndVal) metric, but there are weaknesses in the application of this approach in complex montane systems. We surveyed birds, small mammals, bats, and leaf-litter lizards in differentially disturbed cloud forest of the Ecuadorian Andes. We then incorporated elevation in generalized linear (mixed) models (GL(M)M) to screen for EDIS in the data set. Finally, we used rarefaction of species accumulation data to compare relative monetary costs of identifying and monitoring EDIS at equal sampling effort, based on species richness. Our GL(M)M generated greater numbers of EDIS but fewer characteristic species relative to IndVal. In absolute terms birds were the most cost-effective of the 4 taxa surveyed. We found one low-cost bird EDIS. In terms of the number of indicators generated as a proportion of species richness, EDIS of small mammals were the most cost-effective. Our approach has the potential to be a useful tool for facilitating more sustainable management of Andean forest systems.