Chaetodipus goldmani, Osgood, 1900

Don E. Wilson, Thomas E. Lacher, Jr & Russell A. Mittermeier, 2016, Heteromyidae, Handbook of the Mammals of the World – Volume 6 Lagomorphs and Rodents I, Barcelona: Lynx Edicions, pp. 170-233 : 219

43.

Goldman’s Pocket Mouse

Chaetodipus goldmani

French: Souris-a-abajoues de Goldman / German: Goldman-Rauhaartaschenmaus / Spanish: Raton de abazones de Goldman

Taxonomy. Chaetodipus goldmani Osgood, 1900 ,

Sinaloa, Sinaloa, Mexico.

Based on detailed sequencing of nDNA and mtDNA genes, C. goldmani is a close relative of C. artus . The two species are next closely related to C. nelsoni , and all three are part of the continental lineage of the “modern” clade of coarse-haired pocket mice, along with C. intermedius , C. penicillatus , C. eremicus , and C. pernix . Chromosomal complement of C. goldmani varies widely; six allopatric races have 2n = 50-56 and FN = 54-56. The six chromosomal races described byJ. L. Patton in 1969 have not been recognized taxonomically in this monotypic species. The southern four races are separated from each other by river systems and riparian or more tropical short-tree forest that is occupied by this species’ close relative, C. artus . The northern two races are restricted to relatively mesic areas along rivers and are isolated from each other by arid, mountainous habitat. Chromosomal races are distributed as follows (from north to south): race theta (0; 2n = 52, FN = 54) occurs along the Rio Bavispe; race epsilon (g; 2n = 54, FN = 54) occurs along the Rio Moctezuma; race gamma (7; 2n = 52, FN = 54) occurs south-east of the Rio Yaqui to the Rio Mayo, Sonora; race delta (3; 2n = 50, FN = 54) occurs east of the Rio Mayo and Rio Cuchijaqui, Sonora, and north of the Rio Fuerte, Sinaloa; race alpha (a; 2n = 52, FN = 54) occurs south of the Rio Mayo and west of the Rio Cuchijaqui, Sonora, and north of the Rio Fuerte, Sinaloa; and race beta (B; 2n = 56, FN = 56) occurs south of the Rio Fuerte, Sinaloa. Later morphometric analysis of these races indicated generally concordant morphological distinetion among chromosomal races. Insufficient samples of adult specimens of race theta were available for comparison, but 80% and 83-9%, respectively, of individuals ofthe remaining peripheral races (epsilon and beta) were correctly classified a posteriori based on a discriminant function analysis of external and cranial measurements. Incorrectly classified individuals were mostly misclassified to neighboring races. Correct classification of individuals of the geographically intermediate races (gamma, delta, and alpha) was lower (58:1%, 55-4%, and 53%, respectively), with individuals generally misclassified to neighboring races. Patton indicated that chromosomal complement of C. artus (2n = 54, FN = 54) is not homologous with that of race alpha of C. goldmani but instead is derived from an ancestral complement of 2n = 56 and FN = 54. Monotypic.

Distribution. NW Mexico (Sonoran Desert of S Sonora, W Chihuahua, and N Sinaloa).

Descriptive notes. Head—body mean 83 mm, tail mean 107 mm, ear mean 11 mm, hindfoot mean 24 mm; weight 19-23 g. There is no significant secondary sexual dimorphism. Goldman's Pocket Mouse is a coarse-haired pocket mouse and mediumsized for the genus, with heavily crested and tufted tail thatis longer than head-body length and sharply bicolored. Ears are large, rounded, and blackish, but whitish for distal one-half; a subauricular spotis present. Pelage is relatively coarse with conspicuous spines on rump. Pelage is broccoli-brown, obscured by black hairs along midline and particularly toward rump, with conspicuous pinkish buff lateral stripe and white under parts. A population with black pelage occurs on the lava field south of Moctezuma, Sonora. Goldman’s Pocket Mouse is narrowly sympatric with its close relative, the Narrow-skulled Pocket Mouse ( C. artus ) in the southern one-half of its distribution. Compared with that species, Goldman’s Pocket Mouse is slightly larger, with a wider skull and larger auditory bullae, and has more well-developed rump spines, narrower dorsaltail stripe and more hairy tail, lighter ears, and lighter and less uniform (more grizzled) dorsal pelage. Where the coarse-haired Goldman's Pocket Mouse occurs in the vicinity of either of two smooth-haired pocket mice (the Sinaloan Pocket Mouse, C. pernix , or the Desert Pocket Mouse, C. penicillatus ), it avoidsfine, sandy soils to which the smooth-haired pocket mice are restricted. Bailey's Pocket Mouse ( C. baileyi ), another species that occurs in the general vicinity, is larger, has a lighter-colored pelage lacking rump spines, and favors more open areas of pebbly soils that mark transitions from sandy flats to rocky alluvial slopes or “bajadas.”

Habitat. In the southern part of its distribution, where it is sympatric with its close relative, the Narrow-skulled Pocket Mouse, Goldman’s Pocket Mouse occurs in thorn scrub and short-tree forests on alluvial soils, and is absent or uncommon in riparian communities, along river terraces, or on rocky slopes. The Narrow-skulled Pocket Mouse occupies the closed, more mesic short-tree forest and riparian galleries along river and streambeds, apparently excluding Goldman’s Pocket Mouse and reducing gene flow between its chromosomal races. Further north, where it is sympatric with the Sinaloan Pocket Mouse, Bailey's Pocket Mouse, or the Desert Pocket Mouse, all of which occupy finergrained soils, Goldman’s Pocket Mouse is common near rocks, steep rocky slopes, and dry arroyos and is associated with mesquite ( Prosopis , Fabaceae ).

Food and Feeding. Diet of Goldman's Pocket Mouse consists largely of seeds of shrubs, annuals, and grasses, but it also includes smaller amounts of green vegetation and insects. Food items are collected in external, fur-lined cheek pouches and transported back to burrows, where they are stored in burrow caches. It does not need to drink water, subsisting entirely on water from its food and water produced as a byproduct of metabolism.

Breeding. There is no information available for this species.

Activity patterns. Goldman's Pocket Mouse is nocturnal and terrestrial, and it is active throughout the year.

Movements, Home range and Social organization. There is no information available for this species.

Status and Conservation. Classified as Near Threatened on The [UCN Red List. At least 60% of the historical distribution of Goldman’s Pocket Mouse has been converted to agriculture. In the southern part ofits distribution, threats include agricultural development and use of rodenticides.

Bibliography. Alvarez-Castafeda et al. (2010), Aquino & Neiswenter (2014), Best (1993a), Ceballos & Oliva (2005), Lackey & Best (1992), Patton (1969a), Williams et al. (1993).

Figures

27. Hispid Pocket Mouse (Chaetodipus hispidus), 28. Long-tailed Pocket Mouse (Chacetodipus formosus), 29. Bailey's Pocket Mouse (Chaetodipus bailey), 30. Peninsular Pocket Mouse (Chaetodipus rudinoris), 31. Spiny Pocket Mouse (Chaetodipus spinatus), 32. California Pocket Mouse (Chaetodipus californicus), 33. San Diego Pocket Mouse (Chaetodipus fallax), 34. Little Desert Pocket Mouse (Chaetodipus arenarius), 35. Dalquest’s Pocket Mouse (Chaetodipus ammophilus), 36. Cerralvo Island Pocket Mouse (Chaetodipus siccus), 37. Desert Pocket Mouse (Chaetodipus penicillatus), 38. Chihuahuan Desert Pocket Mouse (Chaetodipus eremicus), 39. Sinaloan Pocket Mouse (Chaetodipus pernix), 40. Rock Pocket Mouse (Chaetodipus intermedius), 41. Nelson’s Pocket Mouse (Chaetodipus nelsoni), 42. Lined Pocket Mouse (Chaetodipus lineatus), 43. Goldman’s Pocket Mouse (Chaetodipus goldmani), 44. Narrow-skulled Pocket Mouse (Chaetodipus artus)

Distribution. NW Mexico (Sonoran Desert of S Sonora, W Chihuahua, and N Sinaloa).