Ben Creisler
New lizard papers:
Bicuspidon hogreli sp. nov.Â
Romain Vullo & Jean-Claude Rage (2018)
The first Gondwanan borioteiioid lizard and the mid-Cretaceous dispersal event between North America and Africa.
The Science of Nature (advance online publication)
Borioteiioidea are an enigmatic group of Cretaceous lizards widely distributed in northern continents (Laurasia). Here, we describe the first borioteiioid lizard from Gondwana, represented by a new species of the polyglyphanodontine genus Bicuspidon, B. hogreli sp. nov., from the Cenomanian Kem Kem beds of Morocco. The discovery of Bicuspidon hogreli sp. nov., which is one of the oldest known member of Polyglyphanodontini, challenges previous assumptions on the center of origin and dispersal of the group. In addition, the known distribution of Bicuspidon (Cenomanian of Utah and Morocco, and SantonianâMaastrichtian of eastern Europe) suggests a complex palaeobiogeographical history for the genus. The existence of a terrestrial dispersal route persisting during the whole Early Cretaceous between North America and Africa is hypothesized to explain some similarities observed between the Cenomanian squamate assemblages of these two continents. Alternatively, dispersal between the two landmasses may have occurred by transatlantic rafting. During the CenomanianâSantonian interval, Bicuspidon colonized the European archipelago probably from North Africa, like many "Eurogondwanan" taxa.
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Callopistes rionegrensis Quadros, Chafrat & Zaher, 2018 sp. nov.
Ana B. Quadros, Pablo Chafrat & Hussam Zaher (2018)
A new teiid lizard of the genus Callopistes Gravenhorst, 1838 (Squamata, Teiidae), from the lower Miocene of Argentina.
Journal of Vertebrate Paleontology e1484754(4)
DOI: 10.1080/02724634.2018.1484754
Although squamates are commonly found in Cenozoic South American deposits, most findings correspond to fragmentary cranial materials or isolated vertebrae. Among the known South American vertebrate fossil localities, the lower section of the Chichinales Formation (Early Miocene, Colhuehuapian South American Land Mammal Age [SALMA]), in Paso CÃrdoba Protected Natural Area, RÃo Negro Province, Argentina, recently yielded an almost complete skull of a previously unknown teiid lizard. Here, we provide a detailed description of this new fossil, based on stereoscopic and high-resolution X-ray computed tomography (CT scan) analyses. Our phylogenetic analysis recovered the new fossil within the monophyletic genus Callopistes, as the sister group of the fossil C. bicuspidatus from upper Mioceneâlower Pliocene sediments (Montehermosan SALMA) of the Monte Hermoso Formation. The new species antedates the oldest previously known fossil record of the genus by at least 14âMa, providing a minimum age of origin for the genus of approximately 20.1âMa (based on recent revisions of the Cenozoic fossil record of SALMA). The current distribution of the two known extant species of Callopistes and the locality from which the new taxon was recovered indicate that this genus had a much broader distribution in the past that included cis-Andean areas of Patagonia during the Miocene. Our phylogenetic results further suggest that Tupinambis uruguaianensis should be allocated to the genus Dracaena.
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AurÃlien Miralles, Julie Marin, Damien Markus, Anthony Herrel, S. Blair Hedges & Nicolas Vidal (2018)
Molecular evidence for the paraphyly of Scolecophidia and its evolutionary implications.
Journal of Evolution (advance online publication)
Free pdf here:
The phylogenetic relationships between the three main clades of worm snakes remain controversial. This question is, however, crucial to elucidate the origin of the successful snake radiation, as these burrowing and miniaturized wormlike organisms represent the earliest branching clades within the snake tree. The present molecular phylogenetic study, intended to minimize the amount of missing data, provides fully resolved interâsubfamilial relationships among Typhlopidae. It also brings robust evidence that worm snakes (Scolecophidia) are paraphyletic, with the scolecophidian family Anomalepididae recovered with strong support as sister clade to the 'typical snakes' (Alethinophidia). Ancestral state reconstructions applied to three different traits strongly associated to a burrowing lifeâstyle (scolecoidy, absence of retinal cones and microstomy) provide results in favour of a burrowing origin of snakes, and suggest that worm snakes might be the only extant fossorial representatives of the primordial snake incursion towards an underground environment.
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relevant to Sphenodon and lizards...
Graham P. Wallis & FÃtima Jorge (2018)
Going under down under? Lineage ages argue for extensive survival of the Oligocene marine transgression on Zealandia.
Molecular Ecology (advance online publication)
DOI: 10.1080/02724634.2018.1484754
25 years ago, it was suggested that currentâday New Zealand, part of the largely sunken continent of Zealandia, could have been completely inundated during the Oligocene Marine Transgression (OMT) some 25â23 million years ago. Such an event would, of necessity, imply that all terrestrial, freshwater, and maybe coastal marine species must have dispersed there since. This idea has generated heated debate, on which geological, palaeontological and molecular data are being brought to bear. Here we review the phylogeographic literature in the form of molecular estimates of divergence times between New Zealand lineages and their closest overseas sister groups. Using an eventâbased approach, we show that these divergence times follow approximately a smooth exponential over the last 50 Ma or more. ~75 of these 248 lineages appear to have survived the OMT in situ; some of these major lineages comprise multiple additional lineages as a result of autochthonous speciation prior to the OMT. Nonâvolant terrestrial animals, freshwater animals and trees are particularly well represented in surviving lineages, whereas marine animals, herbs and shrubs tend to show more recent arrival times. There is no evidence for a deficit of preâOligocene lineages, nor an excess of ones arriving just afterwards. The pattern is one of geometric increase in new lineages with more recent time, reflecting a balance between immigration and extinction. Consequently, this large body of molecular data provides no evidence for complete inundation of New Zealand during the Oligocene. In conjunction with new geological and palaeontological findings, these data suggest that it is time to put the idea to rest.
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