Megascapheus ruidosae
| Ruidoso Pocket Gopher
(Megascapheus ruidosae) | |
|---|---|
| Range | |
 | |
| Taxonomic classification | |
| Order: | Rodentia |
| Suborder: | Supramyomorpha |
| Infraorder: | Castorimorphi |
| Superfamily: | Geomyoidea |
| Family: | Geomyidae |
| Subfamily: | Geomyinae |
| Tribe: | Thomomyini |
| Genus: | Megascapheus |
| Binomial details | |
| Megascapheus ruidosae (E. R. Hall, 1932) | |
| Other resources | |
| Full taxonomic details at MDD | |
In the range map shown on the right, the dark green area represents the distribution of Megascapheus ruidosae according to Bradley et al. (2023). The light green area represents the range of Megascapheus baileyi subspecies actuosus and an area of uncertainty for Megascapheus ruidosae. Accordingly to Bradley et al. (2023), some individuals of actuosus from the type locality in Corona, NM, possessed a mtDNA haplotype reflective of actuosus, whereas others possessed a haplotype associated with ruidosae: "Further studies are needed to determine whether samples of actuosus that presumably hybridize with ruidosae should be assigned to this new species". For more details, see below.
Description
From Bradley et al. (2023): "Its color is fuscous to fuscous-black above with underparts having a strong wash of ochraceous-tawny; its tail is black except for the distal third which is white; its feet and ankles are white; its skull is relatively broad and generally moderate in size."
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 |
|---|---|---|---|---|---|---|
| Holotype MVZ:Mamm:50431 (Ruidoso, Lincoln Co., NM) | Museum of Vertebrate Zoology | 200 | 60 | 29 | 98 |
Skull
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Holotype: MVZ:Mamm:50431. Megascapheus ruidosae. Female. Ruidoso, Lincoln County, New Mexico. Collected 30 September 1931. Dorsal view of the skull. -
Holotype: MVZ:Mamm:50431. Megascapheus ruidosae. Female. Ruidoso, Lincoln County, New Mexico. Collected 30 September 1931. Ventral view of the skull. -
Holotype: MVZ:Mamm:50431. Megascapheus ruidosae. Female. Ruidoso, Lincoln County, New Mexico. Collected 30 September 1931. Lateral view of the skull. -
Holotype: MVZ:Mamm:50431. Megascapheus ruidosae. Female. Ruidoso, Lincoln County, New Mexico. Collected 30 September 1931. Lateral view of the right mandible.
Taxonomic notes
Elevation of subgenera within genus Thomomys Wied-Neuwied, 1839
Genetic analyses (CytB and COI) by Álvarez-Castañeda and Segura-Trujillo (2025) found that the two subgenera within the genus Thomomys Wied-Neuwied, 1839 — Megascapheus and Thomomys — are genetically distinct. Morphological and genetic data support considering these differences sufficient at the genus level. Both subgenera Megascapheus and Thomomys were elevated to the taxonomic rank of genus by Álvarez-Castañeda and Segura-Trujillo (2025).
Challenges associated with assigning subspecies actuosus to species ruidosae or baileyi
Bradley et al. (2023) used DNA sequence data obtained from the mitochondrial cytochrome-b gene, as well as previous morphometric, allozymic, karyotypic, and DNA studies, to assess variation at the subspecific and species level for the three genera of pocket gophers occurring in Texas and surrounding areas. The work of Bradley et al. has importantly shed light on the taxonomy of many of these cryptic species. For Megascapheus ruidosae they add: "Although this study represents, by far, the most intensive compilation of data, it is far from being the final authority on pocket gopher systematics and taxonomy. For example, some individuals of T. baileyi actuosus from the type locality in Corona, NM, possessed a mtDNA haplotype reflective of T. baileyi actuosus, whereas others possessed a haplotype associated with T. baileyi ruidosae. This finding supports the study of Ruedi et al. (1997) who assumed hybridization between the two subspecies. Clearly, the presence of hybridization at a type locality of a taxon presents a challenge for future taxonomic studies. Given the close proximity of several sampling sites for supposedly different taxa and the propensity for pocket gophers to hybridize (several previously documented hybrid zones), it would be reasonable to assume there are other regions where hybridization is occurring... Further studies are needed to determine whether samples of actuosus that presumably hybridize with ruidosae should be assigned to this new species."
Genetic divergence from connectans
From Bradley et al. (2023): "Given the magnitude of genetic distinction, it may be appropriate to assign all recognized subspecies contained in this group to T. ruidosae (which has priority over connectens). However, connectens differs from the clade containing ruidosae by 7.70%, and given that relatively large magnitude of genetic divergence, we recognize connectens as a separate species until additional data are available."
Similar species
From Bradley et al. (2023): "ruidosae is most similar to fulvus."
References
Álvarez-Castañeda ST. 2010. Phylogenetic structure of the Thomomys bottae–umbrinus complex in North America. Molecular Phylogenetics and evolution 54(3): 671-679.
Bradley RD, Pham AT, Rich KA, Roberts EK, Soniat TJ, Poehlein CM, Mills MN, Ballard M, Pitts RM, Lindsey LL, Halsey MK. 2023. Genetic identification of pocket gophers (Genera Cratogeomys, Geomys, and Thomomys) in Texas and surrounding areas. Museum of Texas Tech University. https://www.depts.ttu.edu/nsrl/publications/downloads/SP78.pdf
Eydoux JFT, Gervais P. 1836. Sur le genre Pæphagomys et quelques autres rongeurs qui l'avoisinent. Magasin de zoologie 6:17-24.