Cylindrophis Wagler, 1828

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

Cylindrophis Wagler, 1828

Material examined.

Cylindrophis maculatus (Linnaeus, 1758) (ZFMK 16549); Cylindrophis ruffus (Laurenti, 1768) (NHMUK uncat.; UF Herp 143722 [Morphosource.org: Media 000445111, ark:/87602/m4/445111]).

Description (Figs 36-42).

Trunk vertebrae. Centrum elongate; cotyle and condyle strongly depressed; neural arch depressed; posterior median notch of the neural arch absent or very shallow; neural spine vestigial and restricted to the posterior portion of the neural arch, disappearing entirely in the posterior vertebrae; prezygapophyseal accessory processes short; relatively elongated hypapophyses restricted to the anterior trunk vertebrae (approximately 36-40 in Cylindrophis ruffus and 50 in Cylindrophis maculatus ); in more posterior trunk vertebrae haemal keel poorly developed and flattened; paracotylar foramina absent.

It is worth noting that Smith (2013) mentioned the presence in Cylindrophis ruffus of distinct anteriorly directed tubercles ventral to the parapophysis in anterior trunk vertebrae and of distinct subcotylar tubercles in the mid- and posterior (but not posteriormost) trunk vertebrae - we did not observe these in our sample and it seems that these features could be intraspecifically variable.

Trunk / caudal transition. No subcentral structures occur in the posterior trunk, cloacal, and caudal vertebrae except for a moderately developed ridge-like keel in the last cloacal and two succeeding caudal vertebrae in Cylindrophis ruffus (Fig. 42 ). Smith (2013) also observed a similar structure in the same species, which he termed “hypapophysis” - observing a photograph of the S 1 of that uncatalogued MNHN specimen of Cylindrophis ruffus that was kindly shared to us by Krister Smith, we consider that this is a very similar structure to the one we call moderately developed ridge-like keel in our material of this species.

Number of vertebrae. Cylindrophis maculatus (ZFMK 16549): 201 (191+3+7); Cylindrophis ruffus (NHMUK uncat.): 228 (212+4+12, including three fused posteriormost vertebrae Cylindrophis ruffus (UF Herp 143722): 199 (187+4+8, including a final fusion).

Data from literature and unpublished data from personal communications: Cylindrophis maculatus : 195-209 trunk and cloacal vertebrae plus 8-?9 caudal vertebrae ( Alexander and Gans 1966); Cylindrophis ruffus : 208 trunk vertebrae plus 4 cloacal vertebrae plus 8 caudal vertebrae (UMZC R4.12-3; Jason Head, unpublished data, personal communication to GLG); Cylindrophis ruffus : 203 trunk vertebrae plus 20 cloacal and caudal vertebrae ( Polly et al. 2001); Cylindrophis ruffus : 194 trunk vertebrae plus 3 cloacal vertebrae plus unknown number of caudal vertebrae ( Gasc 1974); Cylindrophis ruffus : 191 trunk vertebrae plus unknown number of cloacal vertebrae plus 10 caudal vertebrae, including a final fusion ( Smith 2013 and Krister Smith, unpublished data, personal communication); Cylindrophis ruffus : 188 trunk vertebrae plus 14 cloacal and caudal vertebrae ( Nopcsa 1923); Cylindrophis ruffus : 186 trunk and cloacal vertebrae plus 7 caudal vertebrae ( Alexander and Gans 1966); Cylindrophis ruffus : 184-187 trunk vertebrae plus unknown number of cloacal and caudal vertebrae ( Polly and Head 2004); Cylindrophis ruffus : 180-183 trunk vertebrae plus unknown number of cloacal and caudal vertebrae ( Tsuihiji et al. 2012); Cylindrophis ruffus : 163 trunk vertebrae plus 9 cloacal vertebrae (apparently erroneous) plus 15 caudal vertebrae ( Rochebrune 1881).

It should be noted that recently Cylindrophis ruffus has been recognized as a species complex, with several new cryptic species established (e.g., Amarasinghe et al. 2015; Kieckbusch et al. 2016, 2018; Bernstein et al. 2020); therefore, it is not certain whether all these dry skeletons (in particular specimens that were collected during the 18th, 19th, and/or early 20th centuries) that were studied by us or were mentioned in older literature, belong indeed to Cylindrophis ruffus or some other species.

Figures

Figure 42. Cylindrophiidae: Cylindrophis ruffus (NHMUK uncat.), cloacal and caudal vertebrae.