Part 9

Diagnosis.--Size medium to large for the species; ground color of dorsum of paratypes near Olive Brown; darkest of specimens of this subspecies examined (from Potrero Viejo, Veracruz) between Prouts Brown and Mummy Brown; distal two-thirds of guard hairs of dorsum black, proximal third dark gray to sooty; hairs of dorsum black-tipped having subterminal band of Ochraceous-Tawny; sides paler (less of dark brown) than dorsum; venter Deep Olive Buff to clay color, individual hairs pale olive buff at tips, dark gray basally; region of throat and chin sooty gray; ventralmost vibrissae white to base, other vibrissae black to base; ears dark brown, sparsely haired; forefeet and hind feet flesh-colored in palest specimens, sooty in darkest; tail pale brown, slightly paler below than above; presphenoid only slightly constricted towards midline; average and extreme external and cranial measurements of 10 adults from Cerro Gordo, Veracruz, are as follows: total length, 118.9 (112-127); length of tail vertebrae, 45.1 (42-50); length of body, 74.0 (69-78); length of hind foot, 16.0 (16); length of ear from notch, 12.8 (12-13); occipitonasal length, 19.5 (19.0-20.0); zygomatic breadth, 10.3 (10.0-10.8); postpalatal length, 7.1 (6.7-7.5); least interorbital breadth, 3.9 (3.7-4.0); length of incisive foramina, 4.4 (4.1-4.6); length of rostrum, 6.9 (6.5-7.2); breadth of braincase, 9.5 (9.2-9.7); depth of cranium, 7.1 (7.1-7.4); alveolar length of maxillary tooth-row, 3.3 (3.2-3.3); for photographs of skull, see Plate 1a, and Plate 3a.

Comparisons.--For comparisons with B. m. nigrescens, see account of that subspecies. From B. m. pallidus, B. m. brunneus differs in: dorsal, lateral, and facial coloration deeper reddish brown, more melanins present; venter darker; buff gray rather than whitish buff to gray as in paratypical series; vibrissae black rather than brownish to white; tail sooty, less flesh-colored; forefeet and hind feet averaging slightly grayer; most external and cranial dimensions averaging slightly larger; nasals less attenuated; presphenoid less hour-glass shaped, sides more nearly straight.

From B. m. infernatis, B. m. brunneus differs in: side of face and neck deep reddish-brown rather than yellowish-gray (the differences in dorsal colorations are greater between brunneus and infernatis than between brunneus and pallidus); venter darker buff-gray; tail brownish rather than flesh-colored; forefeet and hind feet average slightly grayer; most external dimensions averaging slightly larger; cranial dimensions nearly the same except length of incisive foramina, which is smaller; presphenoid differs in much the same way as from pallidus.

Remarks.--Specimens from Chichicaxtle, Puente Nacional, 3 km. W Boca del Rio, 1 km. E. Mecayucan, and Rio Blanco (20 km. WNW Piedras Negras), are all paler than the paratypical series and other specimens from within the assigned range of B. m. brunneus. All these specimens from the coastal plain average considerably paler than those from the front range and slopes of the mountains. Specimens from Puente Nacional are intermediate in color between paler, grayish brown, specimens from the coastal plains and the darker, brown, specimens from the mountains. When Allen and Chapman (1897:203) described brunneus, they did so on the basis of the darker brown mice from the higher altitudes. The name, brunneus, sensu stricto, could be restricted to those mice from the higher altitudes of central Veracruz. However, when the mice of intermediate color from Puente Nacional are considered, it seems best to include the material from the coastal plain with brunneus. Crania from the higher altitudes are slightly larger than, but not significantly different from, crania of specimens from the coastal plains. Specimens examined from the coastal plains resemble the darker series of B. m. pallidus to the west in central Mexico. But there is no evidence of gene flow between the paler coastal specimens and B. m. pallidus to the west. In fact, these paler brown mice on the coastal plain grade in color into the darker brown mice from the mountains. The paler mice from the coast may be an incipient subspecies.

The type and paratypes seem to have faded somewhat since they were described by Allen and Chapman (loc. cit.) and by Osgood (1909:259). However, the color of the paratypes and other specimens herein assigned is the feature most useful for distinguishing brunneus from all other subspecies of B. musculus.

Specimens examined.--Total 187 all from VERACRUZ, Republic of Mexico, and distributed as follows: type locality, 4400 ft., 16 (including the type), 6, 1; Cerro Gordo, 1500 ft., 19; Teocelo [= Texolo], 4500 ft., 1; 2 mi. NW Plan del Rio, 1000 ft., 14; Plan del Rio, 1000 ft., 2; Carrizal, 4; Chichicaxtle, 3; Puente Nacional, 500 ft., 1, 2; Santa Maria, near Mirador, 1800 ft., 10; Boca del Rio, 10 ft., 1, 8; Cordoba [= Cordova], 14; 4 km. WNW Fortin, 4; Rio Atoyac, 8 km. NW Potrero, 1; 2 km. N. Paraje Nuevo, 1700 ft., 9; El Xuchil, 1 mi. W. Paraje Nuevo, 6; Potrero Viejo, 1700 ft. 15; Cautlapan [= Ixtaczequitlan], 4000 ft., 16; Micayucan, 1; 3 km. SE Orizaba, 5500 ft., 3; Rio Blanco, 20 km. WNW Piedras Negras, 400 ft, 7; 29 km. SE Cordoba, Presidio, 15; 3 km. N Presidio, 1500 ft., 2; Presidio, 600 meters, 6.

Marginal records.--VERACRUZ: type locality; Chichicaxtle; Boca del Rio, 10 ft.; Rio Blanco, 20 km. WNW Piedras Negras, 400 ft; Presidio; 3 km. SE Orizaba, 5500 ft.

American Museum of Natural History.

U. S. Nat. Museum (Biol. Surv. Coll.).

Chicago Natural History Museum.

Univ. Michigan, Museum of Zoology.

Texas A & M, Coop. Wildlife Res. Coll.

Univ. Illinois, Mus. Nat. History.

=Baiomys musculus grisescens= Goldman

Baiomys musculus griesescens Goldman, Proc. Biol. Soc. Washington, 45:121, July 30, 1932; Ellerman, The Families and Genera of Living Rodents, 2:402, March 21, 1941; Poole and Schantz, Bull. U. S. Nat. Mus., 178:259, March 6, 1942; Goodwin, Bull. Amer. Mus. Nat. Hist., 79(2):160-161, May 29, 1942 (part); Miller and Kellogg, Bull. U. S. Nat. Mus., 205:513, March 3, 1955 (part); Felten, Senck. Biol., 39:136, August 30, 1958; Packard, Univ. Kansas Publs., Mus. Nat. Hist., 9:401, December 19, 1958; Hall and Kelson, The Mammals of North America, 2:661, March 31, 1959 (part).

Type.--Adult female, skin and skull; No. 257083 U. S. Nat. Mus. (Biol. Surv. Coll.); Comayabuela [= Comayaguela] just south of Tegucigalpa, 3100 feet, Honduras; obtained on March 6, 1932, by C. F. Underwood, original number 838.

Range.--Central to south-central Guatemala, east to south-central Honduras. Zonal range: Lower parts of the Merendon Biotic Province of Smith (1949:235). Occurs from 3200 feet at a place 1/2 mi. N and 1 mi. W Salama, Guatemala, up to approximately 4500 feet at Monte Redondo, Guatemala.

Diagnosis.--Size medium to small for the species; general ground color of dorsum between Olive Brown and Buffy Brown; distal fourth of individual guard hairs of dorsum black-tipped, proximal three-fourths gray, underfur black-tipped with subterminal band of Vinaceous-Buff, gray basally; facial region below eye Olive-Buff to Deep Olive-Buff; regions of flanks without black-tipped guard hairs, therefore, appearing paler brownish-buff than dorsum; venter Pale Olive-Buff to whitish in midline, hairs there white to base, laterally grayish basally; hairs in region of throat and chin resemble those of underparts; forefeet and hind feet flesh-colored with grayish suffusion; ears dusky brown; tail almost unicolored, slightly darker brown above than below; coronoid process less acutely falcate than in other subspecies; zygoma bowed. Average and extreme external and cranial measurements of 14 adults from La Piedra de Jesus Sabana Grande, Honduras, are as follows: Total length, 110.7 (100-123); length of tail vertebrae, 44.0 (32-55); length of body, 66.7 (60-70); length of hind foot, 14.1 (12-15); length of ear from notch, 11.8 (10-13); occipitonasal length, 19.3 (18.9-19.8); zygomatic breadth, 10.1 (9.8-10.4); postpalatal length, 6.8 (6.2-7.3); least interorbital breadth, 3.9 (3.8-4.1); length of incisive foramina, 4.3 (4.0-4.5); length of rostrum, 6.9 (6.6-7.2); breadth of braincase, 9.6 (9.2-10.1); depth of cranium, 7.0 (6.8-7.3); alveolar length of maxillary tooth-row, 3.2 (3.0-3.4); for photographs of skull, see Plate 1b, and Plate 3b.

Comparisons.--For comparisons with B. m. pullus and B. m. handleyi, see accounts of those subspecies. From B. m. nigrescens, B. m. grisescens differs in: dorsum less blackish (dark brown to buffy); face buffy below eye rather than brownish-black; venter buffy to whitish in midline, not sooty gray; forefeet and hind feet flesh-colored with gray overtones, not dusky to sooty; zygoma bowed, sides less parallel; braincase and bony palate slightly broader.

Remarks.--Goodwin (1942:160) mentioned that a specimen from the type locality of grisescens was as dark as specimens of B. m. nigrescens from Guatemala. However, all specimens from Guatemala, other than those from Sacapulas, were referred by Goodwin (1934:40) to B. m. nigrescens. My studies reveal a grayish-brown population in central Honduras near to and including the type locality. This population appears to grade into a slightly paler, particularly as concerns color of hind foot and tail, group of Guatemalan mice from 1 mi. S Rabinal, from 1/2 mi. N, 1 mi. E Salama, and from Lake Atescatempa. Specimens from western Guatemala at Nenton and Jacaltenango, on the other hand, are darker brownish-black, more nearly like the paratypical series of nigrescens from the Valley of Comitan, Chiapas, Republic of Mexico. This darker brownish-black color of the back persists in specimens from southern Guatemala and El Salvador (see specimens examined of B. m. nigrescens for localities), and they are best referred to nigrescens. B. m. grisescens, in color and certain cranial characters, therefore, seems to grade into two different subspecies: (1) B. m. handleyi, pale mice in the Rio Negro valley in central Guatemala, and (2) B. m. nigrescens, dark mice from southern Guatemala, and parts of El Salvador.

Felten (1958:136) referred all B. musculus from El Salvador to B. m. grisescens. Although I have not examined the specimens reported on by Felten (loc. cit.), I have examined specimens from Lake Atescatempa, Guatemala (which I refer to grisescens), not too distant from Cerro Blanco, and Finca Las Canarias, Department of Ahuachapan, and Laguna de Guija, Department of Santa Ana (localities listed by Felten). It would seem that specimens from these localities might indeed be grisescens. However, specimens that I examined from 1 mi. S Los Planes, and 1 mi. NW San Salvador were considerably darker than paratypes of grisescens and were nearly intermediate in color between nigrescens and pullus. I refer the specimens from 1 mi. NW San Salvador, and 1 mi. S Los Planes to nigrescens rather than to grisescens.

There is no positive evidence that B. m. grisescens intergrades with B. m. pullus to the south in Nicaragua. But, there is a suggestion that intergradation occurs between these subspecies in a series of 76 skins from La Piedra de Jesus Sabana Grande, Honduras, referable to grisescens. A total of 16 of 76 skins from this locality (21 per cent) possess the mid-ventral white stripe found in 18 of 20 skins (90 per cent), from the type locality of pullus in Nicaragua. Further collection in areas between central Honduras and western Nicaragua may yield specimens of B. musculus that are intermediate in characters between grisescens and pullus.

Specimens examined.--Total 149, distributed as follows: GUATEMALA: 1 mi. S Rabinal, 3450 ft., 14; 1/2 mi. N, 1 mi. E Salama, 3200 ft., 10; Lake Atescatempa, 10. HONDURAS: Cementario, Gracias, 1; Monte Redondo, 1; El Caliche, Cedros, 1; La Flor Archaga, 2, 1; Hatillo, 1; type locality, 7, 6 (including the type), 3; El Zapote, Sabana Grande, 4; La Piedra de Jesus Sabana Grande, 76; Cerro de las Cuches Sabana Grande, 5.

Marginal records.--GUATEMALA: 1/2 mi. N, 1 mi. E Salama, 3200 ft. HONDURAS: El Caliche, Cedros; Hatillo; La Piedra de Jesus Sabana Grande; Cementario. GUATEMALA: Lake Atescatempa; 1 mi. S Rabinal, 3450 ft.

United States National Museum (Biol. Surv. Collections).

American Museum of Natural History.

Univ. Michigan, Museum of Zoology.

=Baiomys musculus handleyi= Packard