Constrictores Oppel, 1811 (sensu Georgalis and Smith 2020)

Szyndlar, Zbigniew & Georgalis, Georgios L., 2023, An illustrated atlas of the vertebral morphology of extant non-caenophidian snakes, with special emphasis on the cloacal and caudal portions of the column, Vertebrate Zoology 73, pp. 717-886 : 717

Constrictores Oppel, 1811 (sensu Georgalis and Smith 2020)

General information.

Constrictores represents a recently defined group encompassing Booidea and Pythonoidea , plus tentatively also Bolyeriidae and Xenophidiidae ( Georgalis and Smith 2020). They comprise the largest known snakes, both extant and extinct (see Georgalis and Smith 2020). They have a widespread current distribution ( Georgalis and Smith 2020), coupled with an extensive and rich fossil record, especially during the Paleogene ( Szyndlar and Rage 2003; Georgalis et al. 2021a; Smith and Georgalis 2022). The group has been recovered as monophyletic in several recent phylogenies (e.g., Slowinski and Lawson 2002; Lee et al. 2007; Pyron et al. 2013; Streicher and Wiens 2016; Zheng and Wiens 2016; Burbrink et al. 2020; Onary et al. 2022; Zaher et al. 2023), although other studies have instead proposed a closer relationship of pythonoids to uropeltoids instead ( Lawson et al. 2004; Reynolds et al. 2014).

The generalized vertebral morphology of Constrictores is defined by massively built vertebrae, with a generally low ratio of their centrum length / neural arch width (<1.1), high neural spines, and a thick zygosphene ( Georgalis and Smith 2020). However, significant deviations exist to this generalized rule, such as the elongated vertebrae of ungaliophiids, or the much thinner zygosphene of several taxa, or the complex caudal morphology of erycids and charinaids.