Morelia Gray, 1842

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

Morelia Gray, 1842

Material examined.

Morelia spilota ( Lacépède, 1804) (MNHW Reptilia -0328; SMF PH 4; SMF PH 6; SMF PH 8; SMF PH 67); Morelia viridis (Schlegel, 1872) (QM J2108; SMF PH 12; SMF PH 22 [juvenile]; SMF PH 183; UF Herp 120539 [Morphosource.org: Media 000408449, ark:/87602/m4/408449]; ZFMK 5212).

Description (Figs 158-161).

Trunk vertebrae. Centrum shorter than wide; cotyle and condyle orbicular; neural arch vaulted; posterior median notch of the neural arch deep; neural spine as high as long. In the neural spine of Morelia viridis , its dorsal edge is slightly expanded laterally and produced anteriorly into a prominent bifurcated spur (these structures disappear in the trunk/caudal transition). Neural spine of posteriormost trunk vertebrae rather short; prezygapophyseal accessory processes vestigial; hypapophyses disappearing at the level of V 60 approximately in M. viridis and after V 70 in M. spilota ; haemal keel in more posterior vertebrae flattened, moderately developed; paracotylar foramina absent. The vertebrae of Morelia spilota illustrated by Gasc (1974: fig. 7) possess relatively much shorter than wide centrum and distinctly higher than long neural spine.

Trunk / caudal transition. The last trunk and cloacal vertebrae provided with a ridge-like haemal keel (in one examined specimen of Morelia viridis expanded posteriorly into a widened spur). Paired haemapophyses first appear usually in the second caudal vertebra (in one specimen of M. viridis [QM J2108] the first haemapophysis is unpaired), although they can also appear in the first caudal ( Morelia spilota [SMF PH 8]). In one specimen of Morelia viridis (SMF PH 183) clearly paired haemapophyses already appear in the last (4th) cloacal vertebra. In one specimen of M. spilota , the first haemapophysis is unpaired and appears already in the last (5th) cloacal vertebra. Posteriormost caudal vertebrae can be fused in M. spilota .

Number of vertebrae. Morelia spilota (SMF PH 67): 392 (305+5+82 [posteriormost caudal vertebrae are fused]); Morelia spilota (SMF PH 6): 366 (277+5+84); Morelia spilota (MNHW Reptilia -0328): 354 (287+5+62); Morelia spilota (SMF PH 8): 320+ (260+4+56+ [posteriormost caudal vertebrae are missing]); Morelia viridis (QM J2108): 339 (248+4+87); Morelia viridis (ZFMK 5212): 317 (240+4+73); Morelia viridis (SMF PH 22 [juvenile]): 326 (237+4+85); Morelia viridis (SMF PH 183): 345 (243+4+98); Morelia viridis (UF Herp 120539): 337 (242+4+91).

Data from literature and unpublished data from personal communications: Morelia spilota : 371 vertebrae in total ( Parmley and Reed 2003); Morelia spilota : 286 trunk vertebrae plus 75 cloacal and caudal vertebrae ( Polly et al. 2001); Morelia spilota : 276 trunk and cloacal vertebrae plus 86 caudal vertebrae ( Python [ Morelia ] Python argus of Alexander and Gans 1966); Morelia spilota : 269 trunk vertebrae plus unknown number of cloacal and caudal vertebrae ( Python argus of Gasc 1974); Morelia viridis : 248 trunk and cloacal vertebrae plus 89 caudal vertebrae (Jingsong Shi, unpublished data, personal communication to GLG); Morelia viridis : 240 ± 2 trunk and cloacal vertebrae plus 83 ± 6 caudal vertebrae ( Alexander and Gans 1966); Morelia viridis : 232-237 trunk vertebrae plus 40-75 cloacal and caudal vertebrae ( Holman 1967).

It is worth highlighting the remarkably high number of caudal vertebrae (reaching up to 98), apparently correlated with the arboreal lifestyle of this genus.