Cylindrophis maculatus (Linneaus 1758) extant was considered closely related to other snakes, including Pachyrhachis. The problem with Wilcox et al. (2002) and Vidal and Hedges (2002) is they placed the most derived burrowing snakes, Anomochilus and Leptotyphlops, at the basal node with no legged taxa, such as Heloderma, included. Here Cylindrophis is derived from a sister toLanthanotus and phylogenetically preceded Uropeltis. The loss of limbs, elongation of the torso, and reduction of certain skull bones are all convergent.
Distinct from Heloderma, the skull of Cylindrophis has a smaller pair of frontals and a longer, narrower set ot parietals. The prefrontals are larger and the maxilla is not so tall. The jugal is reduced both below the orbit and behind it. The postfrontal descends nearly to the maxilla. The retroarticular process is absent. Like Heloderma the coronoid is a raised triangle immediately behind the the dentary. Cylindrophis is non-venemous.
The tail is stocky and closely resembles the head. All four limbs are missing.
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