ALETHINOPHIDIA Nopsca, 1923

Jacisin Iii, John J. & Lawing, A. Michelle, 2024, Fossil snakes of the Penny Creek Local Fauna from Webster County, Nebraska, USA, and the first record of snakes from the Early Clarendonian (12.5 - 12 Ma) of North America, Palaeontologia Electronica (a 2) 27 (1), pp. 1-42 : 7

Infraorder ALETHINOPHIDIA Nopsca, 1923

Diagnosis. Vertebrae of Infraorder Alethinophidia are variable, but can typically be identified by the presence of a neural spine, a somewhat high neural arch, and the presence of a median notch on the posterior border of the neural arch has a median notch ( Rage, 1984; Holman, 2000).

Remarks. While the above characters are true for most of Alethinophidia , both Rage (1984) and Holman (2000) noted exceptions in the Uropeltidae , which lack neural spines, and the genus Coniophis , where the vertebrae lack both a neural spine and a median notch in the posterior neural arch. The “higher neural arch” of Rage (1984) is relative to the lower neural arch of Scolecophidia. Ikeda (2007) examined these characters in additional taxa, and stated that despite the exceptions above, the character states of Rage (1984) and Holman (2000) can be considered diagnostic.