Notiosorex cockrumi
Cockrum's Gray Shrew
(Notiosorex cockrumi) | |
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Range | |
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Taxonomic classification | |
Order: | Eulipotyphla |
Suborder: | Erinaceota |
Family: | Soricidae |
Subfamily: | Soricinae |
Tribe: | Notiosoricini |
Genus: | Notiosorex |
Binomial details | |
Notiosorex cockrumi R. J. Baker, O'Neill, & McAliley, 2003 |
Baker et al. (2003) recognized Notiosorex cockrumi as a species separate from the Desert Gray Shrew (Notiosorex crawfordi) based on nuclear and mitochondrial sequence data.
Description
From Ceballos (ed., 2014): "Hairs of the dorsal pelage of Notiosorex cockrumi are banded, proximally to distally, dark grayish-brown, pinkish-white, to very dark grayish-brown. Hairs of the venter are gray to white. The tail is colored uniformly very dark grayish-brown as for the dorsum."
External measurements
Length measurements are in millimeters (mm) and weight measurements are in grams (g), unless stated otherwise. If available, the sample size (n=) is provided. If a range is not provided and n= is not given, then the listed measurement represents an average.
Part of range | Reference | Total length | Tail length | Hindfoot length | Ear length | Mass |
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not reported | Ceballos (editor, 2014) | 78–86 | 19–27 | 9–11 | 7–9 | 3–6.3 |
Skull
Only three unicuspids in upper jaw; whereas Sorex have four or five.
From Baker et al. (2003): "Cranial measurements (in mm) of the holotype are as follows: greatest length of skull 16.16, rostral breadth 4.8, least interorbital breadth 3.61, cranial breadth 7.95, length of upper unicuspid toothrow 1.81, length of maxillary complex toothrow 3.81, width across M2-M2 4.84, length of mandibular toothrow 4.8, height of coronoid process 4.2, length of coronoid process-ventral point of upper condylar facet 3.39, and length of coronoid process-ventral point of lower condylar facet 3.54."
Similar species
This cryptic species is sympatric with N. crawfordi in Cochise County, Arizona. From Camargo & Álvarez-Castañeda (2020): "individuals of N. evotis, N. crawfordi and N. cockrumi do not have clear morphological characters that could be used to differentiate among them."
Taxonomy notes
From Woodman (2018): "This species represents a hypothesis in need of comprehensive testing. It was originally identified and described on the basis of differences in the sequences of the mitochondrial cytochrome b gene and a portion of intron 7 of the nuclear beta fibrinogen gene between individuals of Notiosorex crawfordi in southern Arizona and Sonora and individuals from throughout the rest of the geographic range of the species. Neither Notiosorex evotis nor Notiosorex villai was included in the analysis as an outgroup, as a gauge of interspecific variation, or to test the distinctiveness of the new species. No morphological or morphometric study was done, making it difficult to identify existing specimens in systematic collections, although the authors noted that Carraway and Timm (2000) “detected no geographically discernable patterns in skin and skull characteristics and measurements across the range of N. crawfordi” (Baker et al., 2003:4). This cryptic species is sympatric with N. crawfordi in Cochise County, Arizona, where one might expect to detect morphological character displacement between two closely related species. Similar molecular data suggest the presence of another morphologically cryptic mitochondrial species in Baja California, Mexico (Baker et al., 2003; Ohdachi et al., 2006; McAliley et al., 2007)."
Distribution notes
From Baker et al. (2003): "What can be documented at this time is that N. crawfordi and N. cockrumi are sympatric over a substantial area of southeastern Arizona. Sequence data will be needed to determine how the ranges of N. crawfordi and N. cockrumi are defined."
References
Baker RJ, McAliley LR, O'Neill MB. 2003. A new species of desert shrew, Notiosorex, based on nuclear and mitochondrial sequence data. Occasional Papers, Museum of Texas Tech University 222:1–12.
Camargo I, Álvarez-Castañeda ST. 2020. A new species and three subspecies of the desert shrew (Notiosorex) from the Baja California peninsula and California. Journal of Mammalogy 101(3):pp.872-886.
Carraway LN, Timm RM. 2000. Revision of the extant taxa of the genus Notiosorex (Mammalia: Insectivora: Soricidae). Proceedings of the Biological Society of Washington 113(1): 302-318.
Ceballos G, editor. 2014. Mammals of Mexico. Baltimore (MD, USA): Johns Hopkins University Press.
McAliley LR, O'Neill MB, Baker RJ. 2007. Molecular evidence for genetic subdivisions in the desert shrew, Notiosorex crawfordi. The Southwestern Naturalist 52(3): 410-417.
Ohdachi SD, Hasegawa M, Iwasa MA, Vogel P, Oshida T, Lin LK, Abe H. 2006. Molecular phylogenetics of soricid shrews (Mammalia) based on mitochondrial cytochrome b gene sequences: with special reference to the Soricinae. Journal of Zoology 270(1): 177-191.