Anomochilidae Cundall, Wallach & Rossman, 1993, 1816

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

Anomochilidae Cundall, Wallach & Rossman, 1993

General information.

A rather enigmatic lineage of snakes. Anomochilidae are known exclusively from a single genus, Anomochilus Berg, 1901, encompassing three species known from only a very few available specimens, distributed in Southeastern Asia and Indonesia ( Wallach et al. 2014). They were once lumped into an expanded concept of Aniliidae (e.g., Boulenger 1893; Dowling 1959; Rage 1987), then to Cylindrophiidae (e.g., McDowell 1975), however, they were subsequently shown to possess unique cranial features and represent a distinct family ( Cundall and Rossman 1993; Cundall et al. 1993). Indeed, morphological data suggested that Anomochilidae were lying at the base of alethinophidians ( Cundall et al. 1993) but recent molecular evidence attests for a closer relationship with cylindrophiids ( Gower et al. 2005; Vidal et al. 2009; Pyron and Burbrink 2012; Zheng and Wiens 2016).

The postcranial osteology of Anomochilus has never been studied. Indeed, so far, the only published source on the vertebrae of anomochilids is an X-ray image of a paratype of Anomochilus monticola Das et al., 2008, provided by Das et al. (2008: fig. 3) (which, however, is not very informative) plus some vertebral counts in the same paper. In a previous study, Smith (1940) also mentioned an X-ray image (which he never figured), but he confined his observation solely to the absence of pelvic bones or femur and said nothing on the vertebrae.

Material examined.

We only had available an X-ray of the posterior trunk, cloacal, and caudal regions of a skeleton (NHMUK 1946.1.17.4) of Anomochilus leonardi Smith, 1940.

Number of vertebrae. Anomochilus leonardi (NHMUK 1946.1.17.4): ~15 cloacal and caudal vertebrae (number of trunk vertebrae unknown).

Data from literature and unpublished data from personal communications: Anomochilus leonardi : 265 trunk and cloacal vertebrae plus 17 caudal vertebrae ( Das et al. 2008); Anomochilus monticola Das et al., 2008: 264 trunk and cloacal vertebrae plus 11 caudal vertebrae ( Das et al. 2008); Anomochilus weberi (Lidth de Jeude, 1890): 246 trunk vertebrae (last with forked rib) plus 4 cloacal vertebrae plus 9 caudal vertebrae (RMNH RENA 4691; Agustin Scanferla, unpublished data, personal communication).