Part 12

GUATEMALA: Chanquejelve, 1; Nenton, 3000 ft., 1; Jacaltenango, 5400 ft., 8; La Primavera, 5; 4 mi. S Guatemala City, 4700 ft., 3; 5 mi. S Guatemala City, 4050 ft., 10; 6 mi. S Guatemala City, 4680 ft., 1; Lake Amatitlan, 4500 ft., 13; El Progresso (Distrito Santa Rosa), 3; 2 mi. N, 1 mi. W Cuilapa, 2980 ft., 1; 1 mi. WSW El Molino (Distrito Santa Rosa), 2; 2-1/2 mi. W, 2-1/4 mi. N San Cristobal, 2900 ft., 1; El Zapote, 1.

EL SALVADOR: 1 mi. NW San Salvador, 29; 1 mi. S Los Planes, 15.

Marginal Records.--CHIAPAS: Bochil; 25 mi. E Comitan, Las Margaritas, 1250 ft. GUATEMALA: Chanquejelve; La Primavera; Jacaltenango, 5400 ft.; 4 mi. S Guatemala City, 4700 ft.; El Progresso. El Salvador: 1 mi. NW San Salvador; 1 mi. S Los Planes. GUATEMALA: El Zapote. CHIAPAS: Mapastepec, 45 m.; Pijijiapan, 10 m.; 6 mi. NW Tonala; 15 mi. SW Las Cruces; Cintalpa, 555 m.; Ocuilapa, 3500 ft.

American Museum of Natural History.

Univ. Michigan, Museum of Zoology.

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

University of Florida Collections.

=Baiomys musculus pallidus= Russell

Baiomys musculus pallidus Russell, Proc. Biol. Soc. Washington, January 29, 1952; Davis and Russell, Jour. Mamm., 35:75, February 10, 1954; Miller and Kellogg, Bull. U. S. Nat. Mus., 205:512; Hall and Kelson, The Mammals of North America, 2:662, March 31, 1959.

Peromyscus musculus brunneus, Elliot, Field Columb. Mus. Publ., 115(8):203, 1907 (part).

Peromyscus musculus [musculus], Osgood, N. Amer. Fauna, 28:257, April 17, 1909 (part).

Baiomys musculus musculus, Miller, Bull. U. S. Nat. Mus., 79:137, December 31, 1912 (part); Miller, Bull. U. S. Nat. Mus., 128:318, April 29, 1924 (part); Davis, Jour. Mamm., 25:394, December 12, 1944 (part); Hooper, Jour. Mamm., 28:50, February 15, 1947 (part); Goldman, Smith, Miscl. Coll., 115:336, July 31, 1951 (part); Miller and Kellogg, Bull. U. S. Nat. Mus., 205:512, March 3, 1955 (part); Booth, Walla Walla Publs., Dept. Biol. Sci., 20:15, July 10, 1957 (part); Hall and Kelson, The Mammals of North America, 2:661, March 31, 1959 (part); Goodwin, Amer. Mus. Novitates, 1929:1, March 5, 1959.

B. [aiomys] m. [usculus] musculus, Hooper, Jour. Mamm., 33:97, February 18, 1952 (part).

B. [aiomys] m. [usculus] nigrescens, Hooper, Jour. Mamm., 33:97, February 18, 1952 (part).

Baiomys musculus nebulosus Goodwin, Amer. Mus. Novitates, 1929, March 5, 1959.

Type.--Adult female, skin and skull; No. 4501 Texas A&M Cooperative Wildlife Collection; 12 kms. NW Axochiapan, 3500 feet, Morelos, Republic of Mexico, obtained on July 28, 1950, by W. B. Davis, original number 5112.

Range.--Guerrero thence eastward into Morelos and west central Puebla along the southern edge of the Transverse Volcanic Biotic Province (Goldman and Moore, 1945:349), south into Oaxaca, see Figure 10. Zonal range: largely Arid Lower Tropical Subzone of Goldman (1951:330). Occurs from near sea level in Oaxaca and Guerrero up to 6550 feet in Oaxaca.

Diagnosis.--Size medium for the species; dorsum Buffy Brown in palest series to Olive-Brown in darkest series, individual hairs Warm Buff, Neutral Gray basally, some with black tips and a subterminal band of Warm Buff, guard hairs of dorsum black-tipped, gray basally; hairs on sides creamy-buff, gray basally; face same color as back fading to white on throat; vibrissae white-tipped, pale brown basally; venter, whitish with tinges of buff on lower throat, individual hairs having tips white to buffy-white, light gray basally; dorsal surface of forefeet and hind feet whitish to flesh-color; tail indistinctly bicolored, brownish above, grayish brown below; zygoma bowed as in B. m. grisescens; tail short; average and extreme external and cranial measurements for 17 adults from Tehuantepec, Oaxaca, are: total length, 117.3 (110-126); length of tail vertebrae, 46.9 (41-51); length of body, 70.4 (65-76); length of hind foot, 15.8 (15-16); occipitonasal length, 18.9 (18.2-20.1); zygomatic breadth, 10.1 (9.7-10.6); postpalatal length, 6.9 (6.6-7.5); least interorbital breadth, 3.8 (3.6-3.9); length of incisive foramina, 4.4 (4.2-4.7); length of rostrum, 6.7 (6.3-7.2); breadth of braincase, 9.3 (8.7-9.7); depth of cranium, 6.6 (6.4-6.8); alveolar length of maxillary tooth-row, 3.2 (3.1-3.4); for photographs of skull, see Plate 1g, and Plate 3g.

Comparisons.--For comparisons with B. m. brunneus and B. m. infernatis, see accounts of those subspecies.

From B. m. musculus, B. m. pallidus differs in: dorsum more olive-gray and brown, less ochraceous on either side of mid-dorsal region; face below eye grayish, not buffy; sides gray with buffy overtone, not creamy with light yellow overtones; venter grayish-white rather than an olive-buff; zygomata more tapering anteriorly; maxillary part of zygoma narrower when viewed from above; external and cranial dimensions smaller.

From B. m. nigrescens, B. m. pallidus differs in: dorsum paler, fewer black hairs medially; face paler, less sooty; vibrissae brownish with white tips rather than black with brownish tips; venter paler; dorsal surface of forefeet and hind feet whitish to flesh-colored rather than sooty to dusky-white; tail paler; nasals slightly more attenuated; averaging slightly larger in external and cranial measurements.

Remarks.--Russell (1952:21) described pallidus, on the basis of specimens from the arid Balsas Basin, of Morelos, as pale gray dorsally. After examining the original material from Morelos, I find the dorsal color of pallidus to be much closer to a buffy brown than a pale grayish. Even so, smaller size differentiates pallidus from musculus. B. m. infernatis, not B. m. pallidus, is the most pallid of all named subspecies of B. musculus.

B. m. pallidus intergrades to the northwest with B. m. musculus, to the northeast with B. m. infernatis, and to the southeast with B. m. nigrescens.

According to Goodwin (1959:2), B. m. nebulosus (named on the basis of one specimen) differs from B. m. musculus [= pallidus] from southern Oaxaca in: darker and longer pelage; larger skull; interorbital region broader and less constricted posteriorly. From B. m. nigrescens and B. m. brunneus, B. m. nebulosus differs as follows: pelage longer and softer; skull larger.

Study of specimens of B. musculus from Oaxaca reveals considerable variation in external and cranial measurements as well as color, corresponding to that reported by Goodwin (loc. cit.). Specimens from higher altitudes average somewhat darker and larger in external and cranial size than those at lower elevations. These differences seem to be microgeographic and not of subspecific rank. Among specimens that I have studied in Oaxaca are several from different localities (KU 63052, an adult male, from 3 mi. W Miahuatlan; KU 68964, an adult male from 3 mi. W Mitla, 6000 ft.; KU 63055, an adult female from 3 mi. S Candelario, 1200 ft.) that, according to Goodwin (in. litt.) match nebulosus in reported color, size of body and skull (except for the region of the rostrum).

Two of the three specimens (KU 63052 and 63055) are the darkest of a series in which the palest are inseparable from B. m. pallidus. Goodwin, who kindly compared the three specimens with the type of nebulosus, mentioned (in. litt.) that the skull of the type has a slenderer rostrum. Included in the series of skulls of B. m. pallidus from 3 mi. W Mitla are several adults (not seen by Goodwin) with slender rostra. B. m. nebulosus is judged to be a synonym of B. m. pallidus.

Populations of pygmy mice occurring in partially isolated areas of highland in Oaxaca seem to me to be incipient subspecies.

Specimens examined.--Total 824 all from the Republic of Mexico and distributed as follows: PUEBLA: 2 mi. S Atlixco, 5800 ft., 1; 1 mi. SSW Tilapa, 5800 ft., 2; 6 mi. SW Izucar de Matemores, 7; Piaxtla, 3900 ft., 4; Acatlan, 4100 ft., 1. MORELOS: 5 mi. W Tepoztlan, 6000 ft., 7; 1 mi. W Tepoztlan, 6000 ft., 9; 2 mi. SW Tepoztlan, 7000 ft., 1; Cuernvaca, 9; 6 mi. W Yautepec, 4500 ft., 1; Yautepec, 12; 3 mi. N Alpuyeca, 4000 ft., 2; Puente de Ixtla, 2; Tetecala, 4; 2 km. S Jonacatepec, 4500 ft., 6; type locality, 6 (including the type). GUERRERO: Yerbabuena, 1800 m., 1; Cueva de tia Juana [= 1.5 km. SSW Yerbabuena], 1; Laguna Honda, 1840 m. [= 1.5 km. S Yerbabuena], 3; 9 mi. SE Taxco, 3800 ft., 1; 17 km. S Taxco, 4000 ft., 2; Iguala, 5; 3.2 km. SSE Iguala, 970 m., 1; 1 km. SSE Texcaizintla, 1600 m., 2; Teloloapan, 20, 5; 1 km. N Chapa, 1470 m., 6; Chapa, 1470 m., 5; El Limon, 3; 2-1/2 mi. W Mexcala, 2100 ft., 1; Rio Balsas, 1; Ayusinaha [= Ayotzinapa], 1; Tlapa, 3900 ft, 1; 2.5 mi. S Almolonga, 5600 ft., 13; 1 km. N Zihuatanejo, 1; Zihuatanejo Bay, 4; Las Gatas [= 2 km. S. Zihuatanejo], 2; 2 km. SSE Zihuatanejo, 9; 4 mi. W Chilpancingo, 5800 ft., 3; Chilpancingo, 4800 ft., 14, 21, 45; 2 mi. N Tixtla, 4400 ft., 3; 3.2 km. S Chilpancingo, 4; Cd. Chamilpa [= 12 km. ESE Chilpancingo], 5; Tlalixtaquilla, 4200 ft., 2; 15 km. S. Chilpancingo, 4300 ft., 10; 1 mi. SW Colotlipa, 2700 ft., 16; 2 mi. SW Colotlipa, 2700 ft., 1; Achuitzotla, 2800 ft., 7; 8 mi. SW Colotlipa, 1; 5 mi. S Rincon, 2600 ft., 2; 8 mi. SW Tierra Colorado, 600 ft., 1; Rio Aguacatillo, 30 km. N Acapulco, 1000 ft., 3; 5 mi. ESE Tecpan, 50 ft., 9; Ejido Viejo, 12 km. NNW Acapulco, 1; 2 mi. NNW Acapulco, 7; Acapulco, 3, 3; Omentepec, 200 ft., 7. OAXACA: 4 mi. E Huajuapam, 5000 ft., 1; 2 mi. NW Tamazulapan, 6550 ft., 1; Yalalag, 3000 ft., 5; 11 mi. NW Oaxaca [City], 1; Yaganiza, 3900 ft., 1; Oaxaca , 5000 ft., 15, 7, 7, 5; 3 mi. ESE Oaxaca [City], 30; 4 mi. ESE Oaxaca [City], 5050 ft., 1; 10 mi. SE Oaxaca , 1; Cerro Ocotepec, 1; Tepantepec, 9; 1 mi. E Tlacolula, 5500 ft., 53; 3 mi. W Mitla, 11; Jalapa, El Campanario, 1; 2 mi. SE Matalan, 5950 ft., 14; Lachiguiri, 2; Tres Cruces, 10; Agua Blanca, 11; San Jose, 1; Reforma, 30, 7, 10, 6 Totolapa, 1; Nejapa, 85 km. WNW Tehuantepec, 500 m., 12, 6; Chicapa, 2; Gueladu [= Jalapa], 6; Juchitan, Laguna Superior; Manteca, 8, 1; San Bartolo, 3000 ft., 1; Ejutla, 1400 m., 21; El Bambita, Tequisitlan 4; Mixtequilla, 2; Guiencola, 5; Tehuantepec, 200 ft., 26, 11; Sola de la Vega, 26, 3; Huilotepec, 13, 3; Santa Lucia, 24; Cerro de Paste, Tenango, 7; Sta. C. Quieri, 3; Santa Marie Ecatepec, Zarzamora, 13; Rincon Bamba, 11; 3 mi. W Miahuatlan, 5300 ft., 1; Miahuatlan, 12, 1, 6; San Juan Acaltepec, 5; Zapotitlan, 1; Llano Grande, 3; Pinotepa, 700 ft., 2; Juquila, 8; Arroyo, San Juan, north of Cerro Otate, 1; Cerro Otate, 3; 3 mi. S Candelaria, 1.