Systematic revision of the early Miocene fossil Pseudoepicrates (Serpentes: Boidae): implications for the evolution and historical biogeography of the West Indian boid snakes (Chilabothrus)

Abstract

The taxonomy of the early Miocene genus Pseudoepicrates is controversial. Originally interpreted as the viperid Neurodromicus, subsequent work deemed the material to represent an extinct boid, Pseudoepicrates stanolseni. However, more recent work considered Pseudoepicrates to be a synonym of the extant Boa constrictor. Due to these conflicting interpretations, we provide a revision of the systematic affinities of P. stanolseni. This redescription was based on the first-hand analysis of all material of Pseudoepicrates, together with the comparison of extant boids. Our findings suggest that, in addition to being an invalid taxon, 'Pseudoepicrates' cannot be referred to B. constrictor. Instead, the extant Chilabothrus is here regarded as the most cogent generic assignment, with Chilabothrus stanolseni comb. nov. proposed for the extinct species. The referral of this material to Chilabothrus suggests that the genus originated as early as ~18.5 Mya. The revised history of this record has interesting implications for our understanding of the early divergence of the group. The presence of Chilabothrus in the early Miocene of Florida supports biogeographical hypotheses, which suggest that the genus reached the West Indian island complex around 22 Mya, dispersing into the North American territory by at least 18.5 Mya.

Cretaceous Blind Snake from Brazil Fills Major Gap in Snake Evolution

“…The vertebrae of afrophidian snakes (i.e., Henophidia + Caenophidia) differ from those of Boipeba in many respects. In general, Henophidia (e.g., boids and pythonids like Simalia amethistina ; Figure 2 H) sharply differ from the Cretaceous fossil due to a well-developed neural spine, broad and vaulted neural arch (in posterior view) with marked parasagittal ridges and a deep posterodorsal notch, massive zygosphene with median tubercle (in some species), synapophyses subdivided in para- and diapophyses, rounded cotyle and condyle, prezygapophyseal accessory processes reduced to a small pyramidal projection, variable presence of paracotylar and neural arch foramina (sensu Onary and Hsiou, 2018 ), weak interzygapophyseal constriction, pre- and postzygapophyseal facets that are typically inclined between 0° and 15° above horizontal (steeply inclined in Boipeba , ∼25°), and a broad subtriangular centrum with prominent hemal keel and strong precondylar constriction. Boipeba shares with members of the Caenophidia (e.g., Colubroidea) the presence of elongated prezygapophyseal processes.…”

Ocorrência de Anura e Squamata na Coleção Etnográfica Awá-Guajá do estado do Maranhão, Brasil: observações taxonômicas e etnobiológicas

“…Comentários gerais: A classificação como pertencente ao gênero Eunectes é baseado nas suas características diagnósticas mais evidentes como o tamanho grande, espinha neural mode radamente baixa, zigosfeno robusto e modera damente espesso com um tubérculo mediano proeminente (Fig. 4), típicas do gênero (Onary & Hsiou, 2018).…”