We infer phylogenetic relationships within Teioidea, a superfamily of Nearctic and Neotropical lizards, using nucleotide sequences. Phylogenetic analyses relied on parsimony under tree‐alignment and ...similarity‐alignment, with length variation (i.e. gaps) treated as evidence and as absence of evidence, and maximum‐likelihood under similarity‐alignment with gaps as absence of evidence. All analyses produced almost completely resolved trees despite 86% of missing data. Tree‐alignment produced the shortest trees, the strict consensus of which is more similar to the maximum‐likelihood tree than to any of the other parsimony trees, in terms of both number of clades shared, parsimony cost and likelihood scores. Comparisons of tree costs suggest that the pattern of indels inferred by similarity‐alignment drove parsimony analyses on similarity‐aligned sequences away from more optimal solutions. All analyses agree in a majority of clades, although they differ from each other in unique ways, suggesting that neither the criterion of optimality, alignment nor treatment of indels alone can explain all differences. Parsimony rejects the monophyly of Gymnophthalmidae due to the position of Alopoglossinae relative to Teiidae, whereas support of Gymnophthalmidae by maximum‐likelihood was low. We address various nomenclatural issues, including Gymnophthalmidae Fitzinger, 1826 being an older name than Teiidae Gray, 1827. We recognize three families in the arrangement Alopoglossidae + (Teiidae + Gymnophthalmidae). Within Gymnophthalmidae we recognize Cercosaurinae, Gymnophthalminae, Rhachisaurinae and Riolaminae in the relationship Cercosaurinae + (Rhachisaurinae + (Riolaminae + Gymnophthalminae)). Cercosaurinae is composed of three tribes—Bachiini, Cercosaurini and Ecpleopodini—and Gymnophthalminae is composed of three—Gymnophthalmini, Heterodactylini and Iphisini. Within Teiidae we retain the currently recognized three subfamilies in the arrangement: Callopistinae + (Tupinambinae + Teiinae). We also propose several genus‐level changes to restore the monophyly of taxa.
ABSTRACT The Lygodactylus genus is one of the most species-rich genera of gekkonid lizards in Africa. It is one of relatively few exclusively diurnal geckos’ lineages and its members include some of ...the smallest gekkonids. Osteological features within Lygodactylus have never been addressed in detail. We here provide a detailed bone-by-bone skull description of Lygodactylus picturatus to expand the knowledgebase on gecko cranial structure. High-Resolution X-ray Computed Tomography (HRCT) has been used, followed by bone-by-bone segmentation and description. As expected, L. picturatus presents some modifications on the basic gekkotan plan due to miniaturisation, such as an increase in the overlap area of the muzzle unit and lost or reduction of jugal bone. In addition, the skull of this species is characterised by the absence of the squamosal, fused nasals, reduced postorbitofrontal bone and extremely rounded parietal bones. Finally, we observed a reduction of the orbital space, in comparison with other miniaturised gekkotans, presumably as a consequence of their diurnal behaviour and niche preference.
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•Many studies analyze higher-level relationships with many genes but few taxa (e.g. phylogenomic).•Alternately, other studies analyze many taxa but few genes (e.g. supermatrix).•Here, ...we demonstrate the potential to combine these two approaches, using published data from squamate reptiles.•The tree from the combined analysis more closely resembles the higher-level phylogeny based on many genes and few taxa.•We provide a time-calibrated tree for squamate reptiles based on 52 genes and 4162 species.
Two common approaches for estimating phylogenies in species-rich groups are to: (i) sample many loci for few species (e.g. phylogenomic approach), or (ii) sample many species for fewer loci (e.g. supermatrix approach). In theory, these approaches can be combined to simultaneously resolve both higher-level relationships (with many genes) and species-level relationships (with many taxa). However, fundamental questions remain unanswered about this combined approach. First, will higher-level relationships more closely resemble those estimated from many genes or those from many taxa? Second, will branch support increase for higher-level relationships (relative to the estimate from many taxa)? Here, we address these questions in squamate reptiles. We combined two recently published datasets, one based on 44 genes for 161 species, and one based on 12 genes for 4161 species. The likelihood-based tree from the combined matrix (52 genes, 4162 species) shared more higher-level clades with the 44-gene tree (90% vs. 77% shared). Branch support for higher level-relationships was marginally higher than in the 12-gene tree, but lower than in the 44-gene tree. Relationships were apparently not obscured by the abundant missing data (92% overall). We provide a time-calibrated phylogeny based on extensive sampling of genes and taxa as a resource for comparative studies.
Mosasaurs are large, carnivorous aquatic lizards with a global distribution that lived during the Late Cretaceous. After 200 years of scientific study, new mosasaur species are still being discovered ...as new localities are explored and specimens collected long ago are reevaluated using modern standards of species delimitation. Even so, the phylogenetic positions of many key taxa are unresolved and therefore our understanding of mosasaur macroevolution is muddled. Here, we describe a new genus and species of mosasaurine mosasaur comprising a partial skull and skeleton from the Pembina Member of the Pierre Shale Formation in Cavalier County, North Dakota. The lower bound on the age of the specimen is 80.04 ±0.11 Ma, provided by the underlying bentonite bed. Its skull and jaws are nearly complete, and the postcranial skeleton preserves seven cervical vertebrae with three hypapophyseal peduncles, 11 ribs, and five anterior dorsal vertebrae. The new specimen was scored into a modified version of an existing phylogenetic matrix of Mosasauroidea and was recovered in a polytomy with Clidastes; however, given that its morphology is significantly different from that of Clidastes, we refer it to a new genus and species, Jormungandr walhallaensis. Notably, this new taxon shares a mosaic of features seen in both basal (e.g., Clidastes; high dental counts) and derived (e.g., Mosasaurus; subrectangular quadrate) mosasaurines, in addition to possessing its own unique suite of autapomorphies. Given that it possesses morphology intermediate between Clidastes and Plotosaurini, we suspect that future analyses of mosasaur phylogeny, following the addition of new characters and taxa, will recover Jormungandr as transitional between them. Its occurrence increases the known diversity of mosasaurs from the Pembina Member and is the earliest mosasaur to possess autapomorphies of Plotosaurini. Finally, we also analyzed the matrix using different outgroups to test their effect on tree topology and resolution, and found that including multiple nonmosasauroid anguimorphs increased resolution, but not support, of mosasaurid ingroup relationships.
We describe a new species of
Ninia
Baird & Girard, 1853 endemic to the cloud forests of northwestern Ecuador. The new species has previously been confused with
N. atrata
(Hallowell, 1845) and
N. ...teresitae
(Angarita-Sierra and Lynch 2017) but is genetically most closely related to a third species of
Ninia
endemic to the Chocoan–Tumbesian transition area of western Ecuador. We revalidate the name
N. schmidti
(Jan, 1862), designate a neotype, and provide a diagnosis of the taxon and a description of its hemipenial morphology based on new material. The new and revalidated species can easily be identified from one another and from other trans-Andean South American
Ninia
based on ventral and subcaudal scale counts, hemipenial morphology, and coloration of the supralabials, throat, and belly. Finally, we remove
N. atrata
from the herpetofaunal list of Ecuador.
Pereira et al discuss the distribution extension of Alopoglossus buckleyi (O'Shaughnessy, 1881) (Squamata: Alopoglossidae). On Sep 2018 an individual of Alopoglossus buckleyi was captured in a ...pitfall trap at the Cazumba-Iracema Extractive Reserve in the State of Acre, Brazil. Although knowledge on the taxonomic status of Alopoglossus has increased in recent years, many species still lack important information about natural history and distribution, which increases the need for further studies. This new record highlights our lack of knowledge on A. buckleyi, which is the result of poor sampling in many areas of the Amazon.
Phylogenetic and morphological analyses delimit and diagnose, respectively, a new population of a karst-dwelling Cyrtodactylus from extreme northern Thailand. The new species, Cyrtodactylusphamiensis ...sp. nov., of the chauquangensis group inhabits karst caves and outcroppings and karst vegetation in the vicinity of Pha Mi Village in Chiang Rai Province, Thailand. Within the chauquangensis group, Cyrtodactylusphamiensis sp. nov. is the earliest diverging species of a strongly supported clade composed of the granite-dwelling C.doisuthep and the karst-dwelling sister species Cyrtodactylus sp. 6 and C.erythrops. The nearly continuous karstic habitat between the type locality of Cyrtodactylusphamiensis sp. nov. and its close relatives Cyrtodactylus sp. 6 and C.erythrops, extends for approximately 200 km along the border region of Thailand and the eastern limit of the Shan Plateau of Myanmar. Further exploration of this region, especially the entire eastern ~ 95% of the Shan Plateau, will undoubtably recover new populations whose species status will need evaluation. As in all other countries of Indochina and northern Sundaland, the continual discovery of new karst-dwelling populations of Cyrtodactylus shows no signs of tapering off, even in relatively well-collected areas. This only highlights the conservation priority that these unique karstic landscapes still lack on a large scale across all of Asia.
The extant squamates (>9400 known species of lizards and snakes) are one of the most diverse and conspicuous radiations of terrestrial vertebrates, but no studies have attempted to reconstruct a ...phylogeny for the group with large-scale taxon sampling. Such an estimate is invaluable for comparative evolutionary studies, and to address their classification. Here, we present the first large-scale phylogenetic estimate for Squamata.
The estimated phylogeny contains 4161 species, representing all currently recognized families and subfamilies. The analysis is based on up to 12896 base pairs of sequence data per species (average = 2497 bp) from 12 genes, including seven nuclear loci (BDNF, c-mos, NT3, PDC, R35, RAG-1, and RAG-2), and five mitochondrial genes (12S, 16S, cytochrome b, ND2, and ND4). The tree provides important confirmation for recent estimates of higher-level squamate phylogeny based on molecular data (but with more limited taxon sampling), estimates that are very different from previous morphology-based hypotheses. The tree also includes many relationships that differ from previous molecular estimates and many that differ from traditional taxonomy.
We present a new large-scale phylogeny of squamate reptiles that should be a valuable resource for future comparative studies. We also present a revised classification of squamates at the family and subfamily level to bring the taxonomy more in line with the new phylogenetic hypothesis. This classification includes new, resurrected, and modified subfamilies within gymnophthalmid and scincid lizards, and boid, colubrid, and lamprophiid snakes.
ABSTRACT Viviparity has evolved independently multiple times within squamate reptiles. In the Lacertidae, two genera and several species from the Northern Hemisphere are known to be viviparous. ...However, although viviparity is present in many African reptiles, all African lacertids were considered exclusively oviparous. The lacertid genus Tropidosaura is restricted to mountainous grassland habitats across central and southern South Africa. Prompted by the dissection of a gravid T. essexi specimen containing well-developed embryos, we dissected additional gravid females from two museum collections to assess parity mode in the four Tropidosaura species. Gravid females of three species contained developing eggs, but all gravid Tropidosaura essexi specimens examined exhibited simple placental development or contained well-developed embryos with the presence of a simple placenta and an absence of any eggshell. The large yolks and simple placentae suggest that viviparity in T. essexi is lecithotrophic. T. essexi thus represents the only known viviparous species of lacertid in Africa and therefore, the first known viviparous lacertid in the Southern Hemisphere, revealing yet another independent case of the evolution of viviparity within the squamates. T. essexi occurs at higher maximum elevations than any of its oviparous congeners, and the recorded litter size in T. essexi was slightly higher than the clutch sizes of other members of the genus. Previously reported oviparity in T. essexi may either be the result of specimen misidentification or potential bimodal reproductive in this species, but this latter explanation is unlikely, given that none of the T. essexi examined in this study showed evidence of oviparity.
Climate change represents a real threat to biodiversity conservation worldwide. Although the effects on several species of conservation priority are known, comprehensive information about the impact ...of climate change on reptile populations is lacking. In the present study, we analyze outcomes on the potential distribution of the black beaded lizard (
Heloderma
alvarezi
Bogert & Martin del Campo, 1956) under global warming scenarios. Its potential distribution, at present and in projections for the years 2050 and 2070, under both optimistic and pessimistic climate change forecasts, were computed using current data records and seven bioclimatic variables. General results predict a shift in the future potential distribution of
H.
alvarezi
due to temperature increase. The optimistic scenario (4.5 W/m
2
) for 2070 suggests an enlargement in the species’ distribution as a response to the availability of new areas of suitable habitat. On the contrary, the worst-case scenario (7 W/m
2
) shows a distribution decrease by 65%. Moreover, the range distribution of
H.
alvarezi
is directly related to the human footprint, which consequently could magnify negative outcomes for this species. Our research elucidates the importance of conservation strategies to prevent the extinction of the black beaded lizard, especially considering that this species is highly threatened by aversive hunting.
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