Sonora michoacanensis Dugès

Cox, Christian L., Davis Rabosky, Alison R., Holmes, Iris A., Reyes-Velasco, Jacobo, Roelke, Corey E., Smith, Eric N., Flores-Villela, Oscar, McGuire, Jimmy A. & Campbell, Jonathan A., 2018, Synopsis and taxonomic revision of three genera in the snake tribe Sonorini, Journal of Natural History 52 (13 - 16), pp. 945-988 : 977-978

Sonora michoacanensis Dugès in Cope (1885)

Contia michoacanensis Dugès in Cope 1885:178–179. Holotype: Neotype British Museum of Natural History (BMNH) 1903.3.21, now 1946.1.14.65. The original holotype from the Museo Alfredo Dugès was lost ( Stickel 1943; Flores-Villela et al. 2016); a specimen collected in Michoacan with no additional locality information was designated as neotype by Stickel (1943). Type locality: Given as ‘from the state of Michoacan’ in Dugès in Cope (1885). Neotype locality is given as ‘Michoacán’ ( Stickel 1943). Restricted to ‘Apatzingan, Michoacán’ by Smith and Taylor (1950), but they did not provide any evidence for this restriction.

Elapomorphus michoacanensis Cope 1895:218

Homalocranium michoacanense Gunther 1895:150

Chionactis michoacanensis Cope 1896:1024

Scolecophis michoacanensis Boulenger 1896:211–212

Sonora erythura Taylor 1937:69–71 . Holotype: University of Illinois Museum of Natural History ( UIMNH) 25063. Type locality: ‘ 16 km S of Taxco, Guerrero’ .

Sonora michoacanensis michoacanensis Stickel 1943:113

Sonora michoacanensis Ponce-Campos et al. 2004:144–148

Sonora michoacanensis Cox et al. 2012:102

Diagnosis

This species is distinct from Sonora cincta , S. fasciata , S. straminea , S. aemula , S. annulata , S. occipitalis , and S. palarostris by the lack of rostral or caudal adaptations. This species can be distinguished from S. mutabilis based on the almost invariable absence of banding on the tail, and from S. aemula based on the absence of a file-like tail

( Figure 5 ). We note that one specimen from the University of Michigan Museum of Zoology ( UMMZ 109904 ) has a single narrow band on the tail .

Variation

This species is extremely variable in colour pattern, ranging from uniform red to a banded tricoloured pattern ( Echternacht 1973). In tricoloured animals, the number of bands and shape of bands varies greatly ( Echternacht 1973). In some individuals, the black and yellow bands appear as black-bordered yellow spots. Morphological measurements and meristic characters are mostly overlapping between S. mutabilis and S. michoacanensis . The hemipenis is depicted in Cope ( Cope 1895; Plate XXIX, Figure 6 ).

Distribution

This species is found on the Pacific coast and Balsas Basin in the Mexican states of Colima, Guerrero, Michoacan, Morelos, and Puebla ( Figure 6 ).

Remarks

This species is in the subgenus Eosonora along with S. mutabilis .

Figures

Figure 5. Map of the geographic distribution from IUCN and georeferenced occurrence records from GBIF (grey crosses) for the subgenus Chionactis, including Sonora occipitalis, S. palarostris and S. annulata. The top of the map has images of the bicoloured (a), and tricoloured (b) morphs of S. occipitalis. The side panel (c) depicts S. plarostris. The bottom panel depicts the bicolour (d) and tricolour (e) morphs of S. annulata. Photos by T. Brennan (a, b, and c) and M. Mulks (d and e). Colours of shaded ranges and circular points on the map correspond to the phylogenetic tree in Figures 1 and 2.

Figure 6. Map of the geographic distribution from IUCN and georeferenced occurrence records from GBIF (grey crosses) for the subgenus Eosonora, including Sonora mutabilis and S. michoacanensis. The top of the map has images of the bicolour (a) and tricolour (b and c) morphs of S. mutabilis. The bottom panel depicts the tricolour morphs (d and e) of S. michoacanensis that vary in the expression and number of bands. Photos by C. Grunwald (a), C. L. Cox (b), J. Reyes-Velasco (c), A. Mendoza (d) and O. Medina-Aguilar (e). Colours of shaded ranges and circular points on the map correspond to the phylogenetic tree in Figures 1 and 2.