Sonora straminea, (Cope 1860 b)

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 : 974-975

Sonora straminea ( Cope 1860b)

Chilomeniscus stramineus Cope 1860b:339 . Syntypes: The type series is in the USNM (4674 and 6495) . Type locality: ‘Cape St. Lucas, Lower California [Baja California Sur] ’.

Chilomeniscus stramineus stramineus Banta and Leviton 1963:323

Chilomeniscus stramineus Grismer et al. 2002:28

Chilomeniscus stramineus Holm 2008:37

Diagnosis

Sonora straminea can be distinguished from all other Sonora except for S. fasciata and S. cincta by the presence of an elongated rostrum. Sonora straminea is sympatric or narrowly allopatric only with S. fasciata , which shares the elongated rostrum. S. fasciata can be distinguished from S. straminea by the lack of apical maculations.

Variation

Sonora straminea is one of only three species of Sonora that lack coloured bands or stripes, and is uniformly brown. Accordingly, this species lacks colour polymorphism and coral snake mimicry.

Distribution

Sonora straminea is found only in the extreme southern tip of Baja California Sur, Mexico ( Figure 4 ) . Holm (2008) restricts this species to east of the Sierra de la Laguna and south of the Sierra de La Gata .

Remarks

While Sonora straminea is morphologically and genetically distinct from S. fasciata , the potential for hybridization and contact is not well known, and the northern extent of the range of S. straminea (and southern extent for S. fasciata ) bears further study. This species is in the subgenus Chilomeniscus with S. fasciata and S. cincta .

Figures

Figure 4. Map of the geographic distribution from IUCN and georeferenced occurrence records from GBIF (grey crosses) for the subgenus Chilomeniscus, including Sonora cincta, S. fasciata and S. straminea. The top of the map has images of the banded (a) morph of S. cincta. The side panel (b) depicts S. straminea. The bottom panel depicts the banded (c) morph of S. fasciata. Photos by C. L. Cox (a) and J. A. McGuire (b, c). Colours of shaded ranges and circular points on the map correspond to the phylogenetic tree in Figures 1 and 2.