Erratum: Cretaceous blind snake from Brazil fills major gap in snake evolution.

[This corrects the article DOI: 10.1016/j.isci.2020.101834.].

Cretaceous Blind Snake from Brazil Fills Major Gap in Snake Evolution.

Blind snakes (Scolecophidia) are minute cryptic snakes that diverged at the base of the evolutionary radiation of modern snakes. They have a scant fossil record, which dates back to the Upper Paleocene-Lower Eocene (∼56 Ma); this late appearance conflicts with molecular evidence, which suggests a much older origin for the group (during the Mesozoic: 160-125 Ma). Here we report a typhlopoid blind snake from the Late Cretaceous of Brazil, Boipeba tayasuensis gen. et sp. nov, which extends the scolecophidian fossil record into the Mesozoic and reduces the fossil gap predicted by molecular data. The new species is estimated to have been over 1 m long, much larger than typical modern scolecophidians (<30 cm). This finding sheds light on the early evolution of blind snakes, supports the hypothesis of a Gondwanan origin for the Typhlopoidea, and indicates that early scolecophidians had large body size, and only later underwent miniaturization.

A New Clevosaurid from the Triassic (Carnian) of Brazil and the Rise of Sphenodontians in Gondwana.

The early evolution of lepidosaurs is marked by an extremely scarce fossil record during the Triassic. Importantly, most Triassic lepidosaur specimens are represented by disarticulated individuals from high energy accretion deposits in Laurasia, thus greatly hampering our understanding of the initial stages of lepidosaur evolution. Here, we describe the fragmentary remains of an associated skull and mandible of Clevosaurus hadroprodon sp. nov., a new taxon of sphenodontian lepidosaur from the Late Triassic (Carnian; 237-228 Mya) of Brazil. Referral to Sphenodontia is supported by the combined presence of a marginal dentition ankylosed to the apex of the dentary, maxilla, and premaxilla; the presence of 'secondary bone' at the bases of the marginal dentition; and a ventrally directed mental process at the symphysis of the dentary. Our phylogenetic analyses recover Clevosaurus hadroprodon as a clevosaurid, either in a polytomy with the Late Triassic to Early Jurassic Clevosaurus and Brachyrhinodon (under Bayesian inference), or nested among different species of Clevosaurus (under maximum parsimony). Clevosaurus hadroprodon represents the oldest known sphenodontian from Gondwana, and its clevosaurid relationships indicates that these sphenodontians achieved a widespread biogeographic distribution much earlier than previously thought.

Fossil snakes (Squamata, Serpentes) from the tar pits of Venezuela: taxonomic, palaeoenvironmental, and palaeobiogeographical implications for the North of South America during the Cenozoic/Quaternary boundary.

BACKGROUND: Tar seep deposits in South America historically are well-known for their rich record of fossil mammals, contrasting with only a few formal reports of reptile remains. Here we report a new snake fauna recovered from two tar pits from Venezuela. The fossil remains come from two localities: (a) El Breal de Orocual, which comprises an inactive tar seep estimated to be Plio/Pleistocene in age; and (b) Mene de Inciarte, an active surface asphalt deposit with an absolute age dating to the late Pleistocene. METHODS: The taxonomic identity of all specimens was assessed via consultation of the relevant literature and comparison with extant specimens. The taxonomic assignments are supported by detailed anatomical description. RESULTS: The Mene de Inciarte snake fauna comprises vertebral remains identified as the genus Epicrates sp. (Boidae), indeterminate viperids, and several isolated vertebrae attributable to "Colubridae" (Colubroidea, sensu Zaher et al., 2009). Amongst the vertebral assemblage at El Breal de Orocual, one specimen is assigned to the genus Corallus sp. (Boidae), another to cf. Micrurus (Elapidae), and several others to "Colubrids" (Colubroides, sensu Zaher et al., 2009) and the Viperidae family. CONCLUSIONS: These new records provide valuable insight into the diversity of snakes in the north of South America during the Neogene/Quaternary boundary. The snake fauna of El Breal de Orocual and Mene de Inciarte demonstrates the presence of Boidae, Viperidae, "colubrids", and the oldest South American record of Elapidae. The presence of Corallus, Epicrates, and viperids corroborates the mosaic palaeoenvironmental conditions of El Breal de Orocual. The presence of Colubroides within both deposits sheds light on the palaeobiogeographical pattern of caenophidians snake colonization of South America and is consistent with the hypothesis of two episodes of dispersion of Colubroides to the continent.