Baiomys True 1893

Wilson, Don E. & Reeder, DeeAnn, 2005, Order Rodentia - Family Cricetidae, Mammal Species of the World: a Taxonomic and Geographic Reference (3 rd Edition), Volume 2, Baltimore: The Johns Hopkins University Press, pp. 955-1189 : 1049

Baiomys True 1893

Baiomys True 1893 , Proc. U. S. Natl. Mus ., 16: 758.

Type Species: Hesperomys taylori Thomas 1887

Species and subspecies: 2 species:

Species Baiomys musculus (Merriam 1892)

Species Baiomys taylori (Thomas 1887)

Discussion: Baiomyini new tribe. Type genus— Baiomys True, 1894 . Definition—small terrestrial muroid rodents with tail shorter than head-and-body ( Hooper, 1972; Osgood, 1909; Packard, 1960); hindfoot narrow with digits I and V short relative to II-IV, plantar pads 1 and 4 proximally positioned compared with 2-3 ( Carleton, 1980; Osgood, 1909); cranium small but stoutly built, rostrum short, interorbit and braincase lacking ridges; interparietal compressed, wedge-shaped, not contacting squamosal; carotid circulation derived (character state 3 per Carleton, 1980); tegmen tympani adnate to squamosal (Voss, 1993), alisphenoid strut present; M3 cylindrical, less than ½ size of M2; vertebral column with 13 thoracic and 6 lumbar vertebrae, 1 st rib articulating 7 th cervical and 1 st thoracic, humerus lacking entepicondylar foramen ( Carleton, 1980); trochlear process of calcaneum distal ( Carleton, 1980); two complete and five incomplete transverse palatal ridges ( Carleton, 1980); stomach unilocular-hemiglandular, caecum a short simple sac, gall bladder present ( Carleton, 1973, 1980); ampullary glands simple and preputial glands large ( Arata, 1964; Carleton et al., 1975); baculum and phallus short and broad, with a shallow crater and terminal urinary meatus, dorsal and ventral lappets absent ( Blair, 1942; Hooper, 1960); voice a staccato trill, males with prominent midventral glands ( Blair, 1941; Hooper and Carleton, 1976). Contents— Baiomys True, 1894 ; Scotinomys Thomas, 1913 .

Relegated to a subgenus of Peromyscus by Osgood (1909) but reinstated as a separate genus by Miller (1912 b), a status reinforced by Blair (1942) and Hooper (1958). Relationship to South American forms (i.e., Calomys ) advanced by Packard (1960), but other studies have disclosed cognate affinity to Scotinomys ( Carleton, 1980; Carleton et al., 1975; D’Elía, 2003; Engel et al., 1998; Hooper, 1960; Hooper and Musser, 1964 a). Revised by Packard (1960), who delineated subspecific ranges and also summarized fossil taxa (early Pliocene through Pleistocene) within a phylogenetic context. Karyology evaluated by Yates et al. (1979) and biochemical variation by Calhoun et al. (1989). Hershkovitz (1962) transferred the South American form hummelincki , erroneously described under Baiomys , to the phyllotine genus Calomys .