Charina

Diagnosis. As diagnosed in Head (2015), Charina possesses a lobate neural spine that is laterally expanded similar to other Charinainae, and the pterapophyses are anteriorly directed in caudal vertebrae (Kluge, 1993; Szyndlar, 1994). Charina also exhibits a non-U-shaped zygosphene in dorsal view, a strongly concave zygosphene in anterior view, a relatively depressed neural arch, an incised posterior edge of the neural arch, and no paracotylar foramina (Holman, 2000).

Remarks. The fossils described here are similar in size and morphology to known species of Charina. The longer neural spine, the V-shaped (dorsal), strongly concave (anterior) zygosphene, and the depressed neural arch with a relatively deeply incised posterior edge suggest that these vertebrae do not belong to the genus Lichanura; however, it should be noted that Bell and Mead (1996) have observed some intraspecific variation in these characters. As in Parmley and Walker (2003), we instead attribute this fossil to the genus Charina based on the relative length of the neural spine, which is greater than that of Lichanura, and the lack of juvenile characteristics despite being relatively small in size. Parmley and Walker (2003) have observed that Lichanura of a similar size show juvenile characteristics such as a short, high overall morphology, thin neural arch, thin and highly arched zygosphene, exceptionally short neural spine, enlarged neural canal, and a condyle that appears too large for the centrum, none of which are visible in this specimen.

Description (Figs 109 - 112). Trunk vertebrae. Centrum longer than wide or occasionally as wide as long; cotyle and condyle slightly depressed; neural arch depressed; posterior median notch of the neural arch deep; neural spine low; prezygapophyseal accessory processes short to vestigial; hypapophyses disappearing at the level of ca. 50 th vertebra; haemal keel broad, weakly developed; paracotylar foramina absent. Trunk / caudal transition. The last trunk and cloacal vertebrae are provided with a weakly developed haemal keel; no subcentral structures are present in the anteriormost caudal vertebrae. The cloacal vertebrae are abruptly shortened compared to preceding trunk vertebrae and succeeding caudal vertebrae. Paired haemapophyses appear in the 3 rd caudal vertebra. Posterior caudal vertebrae, provided with enlarged neural spine and distinct pterapophyses, are fused into a compact structure. A detailed description of the caudal osteology of Charina will be presented elsewhere. Number of vertebrae. Charina bottae (UMMZ 240637): 256 (212 + 6 +> 38) (about 10 posteriormost caudal vertebrae are fused; precise number of caudal vertebrae cannot be estimated); Charina bottae (NHMUK 1969.2948): 241 (200 + 4 +> 37) (about 10 posteriormost caudal vertebrae are fused; precise number of caudal vertebrae cannot be estimated); Charina bottae (MNHN-RA 0730 [part of the skeleton of the holotype]): ~ 34 caudal vertebrae, including a final fusion (number of trunk and cloacal vertebrae unknown). Data from literature (all for Charina bottae): 215 trunk and cloacal vertebrae plus 44 caudal vertebrae (Alexander and Gans 1966); 209 trunk vertebrae plus 38 cloacal and caudal vertebrae (Holman 1967).

Material examined. Charina bottae (Blainville, 1835) (MNHN-RA- 0730 [part of the skeleton of the holotype]; NHMUK 1969.2948, UMMZ 240637 [Morphosource. org: Media 000068484, ark: / 87602 / m 4 / M 68484]).