Noteworthy Mammals from Sinaloa, Mexico Part 1

Noteworthy Mammals from Sinaloa, Mexico.

by J. Knox Jones, Jr. and Ticul Alvarez and M. Raymond Lee.

In several of the past twelve years field parties from the Museum of Natural History have collected mammals in the Mexican state of Sinaloa.

Most of the collections contained only a modest number of specimens because they were made by groups that stopped for short periods on their way to or from other areas, but several collections are extensive. Field work by representatives of this inst.i.tution now is underway in Sinaloa with the aim of acquiring materials suitable for treating the entire mammalian fauna of that state.

Among the mammals thus far obtained are specimens of twenty species that represent significant extensions of known range, are of especial taxonomic or zoogeographic interest, or that complement published information, and it is these records that are reported herein.

The following persons obtained specimens mentioned beyond: J. R. Alcorn (1950); J. R. and A. A. Alcorn (1954 and 1955); R. H. Baker and a party of students (1955); W. L. Cutter (1957); S. Anderson and a party of students (1959); M. R. Lee (1960 and 1961); and J. K. Jones, Jr., accompanied by R. R. Patterson and R. G. Webb (1961). The Kansas University Endowment a.s.sociation and the American Heart a.s.sociation provided funds that helped to defray the cost of field operations.

In the accounts that follow, all measurements are in millimeters and all catalogue numbers refer to the mammal collection of the Museum of Natural History, The University of Kansas. Placenames a.s.sociated with specimens examined are indicated on the accompanying map (Fig. 1).

_Notiosorex crawfordi_ (Coues).--A non-pregnant female (75184) was obtained on November 29, 1957, at El Fuerte by W. L. Cutter. Comparison of this specimen with topotypes of _N. evotis_ (see below) and with undoubted examples of _N. crawfordi_ proves our specimen to be referable to the latter. We presume that the shrew reported as _evotis_ on geographic grounds from El Carrizo by Hooper (1961:120) also is referable to _crawfordi_. External measurements of our female are: total length, 77; length of tail, 20 (tip missing); length of hind foot, 11; length of ear from notch, 8; weight in grams, 4. Cranial measurements of this individual are given in Table 1.

[Ill.u.s.tration: FIG. 1. Map of Sinaloa on which are plotted symbols representing placenames mentioned in text. From north to south, these are: El Fuerte; San Miguel; Los Mochis; Guamuchil; Terrero; Pericos; Culiacan; El Dorado; Piaxtla and Camino Real (one symbol); Panuco; Mazatlan; Matatan; Rosario; Escuinapa; Concepcion.]

_Notiosorex evotis_ (Coues).--Four topotypes (85533-36), all males, were collected by Lee at Mazatlan. One was caught on December 17, 1960, in a museum special trap set "in low weeds near thorn bush" in a sandy field at the north edge of Mazatlan, less than a mile from the ocean. A few trees and some gra.s.ses grew in this area; _Mus musculus_ and _Perognathus pernix_ were taken in the same line of traps. Additional trapping at this locality failed to produce more shrews. The other three specimens were captured alive on February 1 (one) and February 2 (two), 1961, in the wake of a bulldozer that was clearing land adjacent to the place where the first specimen was trapped. The ground cover being cleared away consisted mostly of dry, dense weeds and short, th.o.r.n.y scrub; the latter was spa.r.s.e in some places and formed dense thickets in others. One individual that was kept alive for a short time in a can ate crickets and roaches readily and ate one spider, but refused isopods. On one occasion it ate six crickets in about three hours. Wet oatmeal and oatmeal mixed with peanut b.u.t.ter both were refused.

Average and extreme external measurements of the four males are as follows: total length, 93.2 (90-98); length of tail, 25.5 (23-27); length of hind foot, 11.9 (11-13); length of ear from notch, 7.7 (7-8); weight in grams, 5.4 (4.4-6.3). Cranial measurements are given in Table 1.

_Notiosorex evotis_ was described by Coues (1877:652) on the basis of a single specimen, obtained at Mazatlan by Ferdinand Bischoff in 1868, that originally had at least the partial skull inside. Subsequently the skull was removed and evidently lost (Poole and Schantz, 1942:181).

Coues named _evotis_ as a species distinct from _crawfordi_ (described by him in the same paper) on the basis of larger size, shorter tail, and alleged slight differences in color. He did not describe the skull, but did note that the dent.i.tion was "substantially the same as that of _N.

crawfordi_." Evidently, the only other correctly identified specimen of _evotis_ on record is an individual from Mazatlan in the British Museum, the skull of which was figured by Dobson (1890:pl. 23, fig. 20).

Merriam (1895:34) characterized _evotis_, known to him by only the holotype, as: "Similar to _N. crawfordi_, but slightly larger and darker." He did not examine the skull, which by that time had been "lost or mislaid." Merriam reduced _evotis_ to subspecific status under _crawfordi_ with the following remarks: "In the absence of sufficient material of _N. evotis_, it is impossible to determine its exact relations to _crawfordi_. Dobson did not recognize it as distinct, but figured its teeth under the name _crawfordi_ [_loc. cit._, possibly a _lapsus_]. For the present it seems best to retain it as a subspecies."

Merriam's arrangement of _evotis_ as a subspecies of _crawfordi_ has been followed by subsequent workers, mostly, we suppose, because additional material of undoubted _evotis_ has not until now been available. Comparisons of our four specimens with specimens (from Jalisco, Sinaloa and Tamaulipas) and published descriptions and measurements (see especially Hoffmeister and Goodpaster, 1954:46-47, 51) of _crawfordi_ reveal that _evotis_ has a longer body and hind foot than _crawfordi_ but a relatively (sometimes actually) shorter tail and ear, and a distinctly larger, heavier skull (see Table 1). The upper parts of our specimens average pale brownish gray and are paler, not darker, than the upper parts of _crawfordi_. But, all of the latter were obtained in the warm months of the year except one November-taken individual from El Fuerte, Sinaloa, the dorsal pelage of which approaches in color that of the darkest of the _evotis_. The pelage of both kinds probably is paler in winter than in summer and may be indistinguishable in the same season. Ventrally, all four _evotis_ are grayish white, faintly to moderately tinged with brownish buff.

_Notiosorex evotis_ differs cranially from _Notiosorex crawfordi_ as follows: larger (see measurements); mesopterygoid fossa squared rather than broadly U-shaped anteriorly; rounded process on maxillary at posterior border of infraorbital ca.n.a.l well developed (faint or lacking in _crawfordi_); occipital condyles smaller and, in lateral view, elevated above basal plane of skull; upper molars slightly more crowded in occlusal view. These differences, although admittedly slight, appear to be constant in the specimens we have seen, but ought to be used cautiously owing to the small samples studied.

Shrews of the genus _Notiosorex_ have been reported twice previously from localities in west-central Mexico, other than from Mazatlan, as follows: 21 mi. SW Guadalajara (remains from owl pellets) and 13 mi. S, 15 mi. W Guadalajara, Jalisco, by Twente and Baker (1951:120-121); and Cerrito Loco, 2 mi. E La Palma, Michoacan (remains from owl pellets), by Baker and Alcorn (1953:116). The remains were referred to _evotis_ on geographic grounds in one instance and were so referred inferentially in the other. Examination of the specimens upon which these reports were based reveals that all are _crawfordi_ on the basis of characters previously cited. As a result, _N. evotis_ is known only from the type locality at Mazatlan, whereas _N. crawfordi_ is widely distributed on the Mexican Plateau as far south as Jalisco and northern Michoacan, and occurs on the west side of the Sierra Occidental as far south as northern Sinaloa.

The two kinds obviously are closely related and intergradation eventually may be demonstrated between them. But, for the present, we adopt a conservative course and treat _evotis_ as a full species owing to its distinctive features, restricted geographic distribution, and the lack of evidence of intergradation between it and _crawfordi_.

_=Balantiopteryx plicata pallida=_ Burt.--Thirty-five specimens from two adjacent localities along the Rio del Fuerte in northern Sinaloa, 3 mi.

NE San Miguel, 300 ft. (84944-48) and 10 mi. NNE Los Mochis (60572-75, 60667-78, 60681-94), provide the first records of the subspecies from the state. Individuals from both localities were shot at dusk as they foraged among trees in the valley of the river. Fifteen of 18 females from 10 mi. NNE Los Mochis, collected on June 5, 6 and 7, 1955, were pregnant; each contained a single embryo, the embryos ranging from 7 to 15 mm. in crown-rump length. _B. p. pallida_ previously has been reported from the southern parts of Baja California and Sonora.

_=Balantiopteryx plicata plicata=_ Peters.--Specimens in the Museum of Natural History from the following localities, several of which are marginal, doc.u.ment better than previously has been done the distribution of this subspecies in Sinaloa: 32 mi. SSE Culiacan (60699); 10 mi. SE Escuinapa (68629); 17 mi. SSE Guamuchil (60576); 5 mi. NW Mazatlan (85537-61, 85901-04); 1 mi. SE Mazatlan, 10 ft. (39461-76); 1 mi. S Pericos (60697-98, 60700); mi. E Piaxtla (60701); mi. W Rosario, 100 ft. (39477-79); 5 mi. SSE Rosario (60702-03); 4 mi. N Terrero (60695-96).

Pregnant females, each with a single embryo, were recorded in 1954 from 4 mi. N Terrero, 2 (June 9), 1 mi. S Pericos, 2 (June 13), and 5 mi. SSE Rosario, 2 (June 20). None of 16 December-taken females from 5 mi. NW Mazatlan was pregnant.

The specimen from 17 mi. SSE Guamuchil, preserved in alcohol, is provisionally referred to _B. p. plicata_ on geographic grounds inasmuch as specimens from the nearby localities of 1 mi. S Pericos and 4 mi. N Terrero, although more grayish on the average than specimens from southern Sinaloa, are somewhat darker and distinctly larger than specimens of _B. p. pallida_ from along the Rio del Fuerte in northern Sinaloa. Specimens from southern Sinaloa average only slightly paler than typical _plicata_ examined from southern Mexico and Nicaragua.

_=Pteronotus psilotis=_ (Dobson).--A total of six specimens from two localities in southern Sinaloa provide the first records from the state and are the northernmost records in western Mexico. The two localities are: mi. S Concepcion, 250 ft. (84987-90); 1 mi. W Matatan (84985-86). The two individuals from the last-mentioned place extend the known range of the species approximately 275 miles north-northwest from a locality 7 mi. W, mi. S Santiago, Colima (Anderson, 1956:349), and place the limit of the known distribution of _P. psilotis_ farther to the north in western Mexico than in the eastern part of the country. We follow Burt and Stirton (1961:24-25) in use of the generic name _Pteronotus_ for this species.

The two specimens from 1 mi. W Matatan were shot at late dusk as they foraged with other bats, presumably of the same species, low over water at the place where the Rio San Antonio joins the larger Rio Baluarte.

The four individuals from mi. S Concepcion were captured in mist nets stretched across the Rio de las Canas at the Sinaloa-Nayarit border, and were taken shortly after dark at heights of three feet or less above the water. Our six specimens all are males. Five are in the reddish color phase and one is in the brownish phase.

Average and extreme measurements of the six males, which average slightly smaller than specimens examined from Colima and Guerrero, are as follows: total length, 66.8 (65-69); length of tail, 16.3 (15-18); length of hind foot, 11.8 (11-12); length of ear from notch, 16.9 (16.5-17.0); length of forearm (dry), 41.5 (40.6-42.4); weight in grams, 8.3 (6.9-9.8); greatest length of skull, 15.4 (15.2-15.5); zygomatic breadth, 8.3 (8.2-8.4); interorbital constriction, 3.4 (3.3-3.6); mastoid breadth, 8.7 (8.6-8.8); length of maxillary tooth-row, 5.8 (5.8-5.9); breadth across M3, 5.4 (5.3-5.6).

_=Sturnira lilium parvidens=_ Goldman.--The first specimens to be reported from Sinaloa are as follows: 32 mi. SSE Culiacan (61087); 1 mi.

S El Dorado (75207); Panuco, 22 km. NE Concordia (85648-50). The three bats from the last-mentioned locality were caught after midnight in a mist net stretched across a road adjacent to a nearly dry stream bed.

The vegetation in the vicinity of the net consisted mostly of dry weeds and gra.s.s along with some low shrubs, but a tree-filled canyon was about one-fourth mile above the net. We lack details about the capture of the other two bats.

_S. l. parvidens_ has been reported only once from farther north in western Mexico than Sinaloa. Anderson (1960:7) recorded five specimens from along the Rio Septentrion, 1 mi. SW Tocuina, Chihuahua.

_=Artibeus lituratus palmarum=_ Allen and Chapman.--This species has been reported once previously from Sinaloa (from 1 mi. S El Dorado by Anderson, 1960:3). Six specimens (85668-72, 85674), all males, collected on December 23 and 24, 1960, at Panuco, 22 km. NE Concordia, provide the second known occurrence in the state.

_=Artibeus toltecus=_ (Saussure).--A male (85666) from Panuco, 22 km. NE Concordia, provides the first record of this species from Sinaloa and extends the known range northwestward approximately 182 miles from Ambas Aguas [= 6 km. SW Amatlan de Jora], Nayarit (Andersen, 1908:300). Our specimen was taken on December 22, 1960, in a mist net placed across a road in an area where vegetation consisted mostly of weeds, gra.s.ses and shrubs. Two _Glossophaga soricina leachii_ and two _Ch.o.e.ronycteris mexicana_ were taken in the same net.

Davis' (1958:165-166) key is useful in separating the small Mexican members of the genus _Artibeus_, but we have found some adults of _toltecus_ to be smaller than the key indicates. For example, in the 12 Mexican specimens (Oaxaca, 6, Tamaulipas, 3, Jalisco, 2, Sinaloa, 1) examined by us the total length of skull varies from 19.7 to 21.0 and the forearm from 36.3 to 42.6.

Dalquest (1953) and more recently Koopman (1961) regarded _A. toltecus_ and the larger _A. aztecus_, which occurs in the same areas but at higher elevations than _toltecus_, as subspecies of the more southerly _A. cinereus_. Davis (_op. cit._), on the other hand, recognized _toltecus_, _aztecus_, and _cinereus_ as distinct species. More specimens of small and medium-sized _Artibeus_ are needed from Mexico before this baffling complex can be studied adequately, but on the basis of specimens examined we are inclined to agree with Davis as concerns the specific distinctness of _toltecus_ and _aztecus_. In Tamaulipas (the mammalian fauna of which is currently under study by Alvarez) for example, _toltecus_ is known from Rancho Pano Ayuctle at an elevation of 300 feet in tropical deciduous forest, whereas _aztecus_ has been taken only four miles away at Rancho del Cielo, but at an elevation of 3000 feet in cloud forest. The alt.i.tudinal difference between ranges of the two kinds in Tamaulipas corresponds to that found in Sinaloa (see Koopman, _loc. cit._) and is of approximately the same magnitude found by Davis at higher elevations in Guerrero. This relationship suggests that the two kinds are neither subspecies of a single species, nor individual variants of a widespread, monotypic species, but probably are two different species. We agree that one, most likely the smaller _toltecus_, may eventually prove to be a northern subspecies of _cinereus_.

_=Myotis occultus=_ Hollister.--A single specimen of this species (67491) from 1 mi. N, mi. E San Miguel provides the first certain record from Sinaloa, and is indistinguishable from specimens from Alamos, Sonora, that were referred to _occultus_ by Hall and Dalquest (1950:587). Miller and Allen (1928:100) identified a skin alone from Escuinapa as _occultus_, but Hall and Dalquest (_loc. cit._) later a.s.signed this specimen provisionally to _M. fortidens_ on geographic grounds and because it agreed in color with undoubted specimens of the latter from Guerrero. Specimens from south of San Miguel and north of the undoubted range of _fortidens_ are needed in order to ascertain whether the two kinds are distinct species or instead only subspecies of a single species.

The Sinaloan bat was taken in a mist net stretched over a drainage ditch adjacent to the Rio del Fuerte on the night of June 19-20, 1955, by R.

H. Baker. Several other kinds of bats were obtained (shot or netted) at the same place, among which was one specimen of _Myotis velifer_. The specimens studied of _occultus_ from Sinaloa and Sonora are clearly separable from specimens of _velifer_ from the same region (Sonora and northern Sinaloa) in having paler (more reddish) pelage, shorter forearm, smaller skull, relatively broader rostrum, and four fewer teeth.

_=Myotis velifer velifer=_ (J. A. Allen).--Three specimens from the following localities in northern Sinaloa provide the first records of the species from the state: El Fuerte (75234); Rio del Fuerte, 1 mi. N, mi. E San Miguel (67490); Rio del Fuerte, 10 mi. NNW Los Mochis (61149). The subspecies _M. v. velifer_ has been reported previously from the adjacent states of Chihuahua, Durango, and Sonora.

A female (61149) obtained on June 8, 1954, carried a single embryo that measured 3 mm. in crown-rump length.

_=Lasiurus borealis teliotis=_ (H. Allen).--A female from 10 mi. NNW Los Mochis (61172), obtained on June 8, 1954, represents the first record of the species from Sinaloa, and is tentatively referred to this subspecies. It resembles cranially, but is paler than, Californian specimens seen of _teliotis_.

_=Molossus ater nigricans=_ Miller.--This large free-tailed bat previously has been reported no farther north in western Mexico than the type locality, Acaponeta, Nayarit. Nineteen specimens from four different localities in Sinaloa are as follows: 1 mi. SE Camino Real, 400 ft. (85093-99); 32 mi. SSE Culiacan (61279-87); 1 mi. S Pericos (61277-78); mi. E Piaxtla (61288). The specimens labeled with reference to Camino Real and Piaxtla were obtained along the Rio Piaxtla at approximately the same place. Those from 1 mi. S Pericos extend the known range of the species approximately 225 miles northwestward.

_M. a. nigricans_ is characteristically an early flier. Along the Rio Piaxtla, 1 mi. SE Camino Real, where bats probably found daytime retreats in the rocky walls of the steep-sided valley of the river, individuals first appeared early in the evening when the sun was still on the western horizon, but were gone before other species of bats were seen. A female from 32 mi. SSE Culiacan, taken on June 18, 1954, contained one embryo that was 18 mm. in crown-rump length. Each of the color phases of the species, reddish (8) and black (11), are represented among our specimens. We follow Goodwin (1960) in the use of the specific name _ater_ for this bat.

_=Dasypus novemcinctus mexica.n.u.s=_ Peters.--Two armadillos (85402-03) from the valley of the Rio del Fuerte, 3 mi. NE San Miguel, 300 ft., are the first of the species to be reported from northern Sinaloa. They extend the known range northwestward in the state approximately 285 miles from Escuinapa (Russell, 1953:25) and signal the possible occurrence of _D. n. mexica.n.u.s_ in southern Sonora. Sign of the armadillo was abundant at the place where our two specimens were collected. Because it was felt that the species possibly had been introduced along the Rio del Fuerte, a number of local residents were questioned on the point, but all insisted that armadillos were native to the area.

External measurements of 85402 (female) and 85403 (male) are, respectively, as follows: total length, 725, 748; length of tail, 351, 357; length of hind foot, 87, 89; length of ear from notch, 39, 39.

_=Sylvilagus audubonii goldmani=_ (Nelson).--This cottontail has been reported from Sinaloa only from Bacubirito, Culiacan (type locality), and Sinaloa (Nelson, 1909:226). Additional records are: 12 mi. N Culiacan (67561-62); 6 mi. N El Dorado (75263); 6 mi. N, 1 mi. E El Dorado (75264-66); 7 mi. NE El Fuerte (81076-77); and 1 mi. S Pericos (61292-93). Specimens from the vicinity of El Dorado extend the known range some 30 miles southward from the type locality. A female from 1 mi. S Pericos that was taken on June 13, 1954, carried three embryos that measured 29 mm. in crown-rump length.

_=Sciurus truei=_ Nelson.--Three specimens (61300-02) of this species collected by A. A. Alcorn on June 19, 1954, 32 mi. SSE Culiacan extend the known range approximately 210 miles south-southeast from Guirocoba, Sonora (Burt, 1938:38), and provide the first record from Sinaloa. Two of the specimens are females and each was pregnant, one with two embryos and the other with three.

Our specimens generally agree in color with _S. truei_, but are larger than typical individuals and in this respect approach _S. sinaloensis_ of southern Sinaloa. Probably _truei_ and _sinaloensis_ both are only subspecies of the more southerly _S. colliaei_. The three nominal species currently const.i.tute the _S. colliaei_ group in which the presence or absence of P3 seems to vary geographically. The tooth frequently is absent in the northern _truei_ and usually present (invariably in the specimens we have examined) in _colliaei_. Only one of our Sinaloan specimens is accompanied by a skull; in it P3 is present on the right side and absent on the left.

External measurements of the male and two females are, respectively: total length, 512, 508, 504; length of tail, 263, 263, 252; length of hind foot, 64, 63, 64; length of ear from notch, 28, 29, 28. Cranial measurements of 61300 (a female) are: greatest length of skull, 56.2; zygomatic breadth, 32.6; interorbital constriction, 17.9; pos...o...b..tal constriction, 17.9; length of nasals, 17.3; alveolar length of maxillary tooth-row (on side lacking P3), 10.9.

_=Th.o.m.omys umbrinus atrovarius=_ J. A. Allen.--Two specimens (85104-05) from the valley of the Rio Piaxtla, 1 mi. SE Camino Real, 400 ft., resemble the description of _atrovarius_ and agree in size, color and most cranial details with a specimen (85744) from 5 mi. NW Mazatlan. The first-mentioned specimens extend the known range of the subspecies some 50 miles northward from Mazatlan (Bailey, 1915:96), and indicate the probable occurrence of the species at lower elevations in other parts of central Sinaloa.

_=Peromyscus merriami goldmani=_ Osgood.--This subspecies has been reported previously only from the type locality, Alamos, Sonora. Eight specimens were collected in Sinaloa by W. L. Cutter in the autumn of 1957 as follows: 6 mi. N, 1 mi. E El Dorado (75368-72); 2 mi. N El Fuerte (75365-66); El Fuerte (75367). The first-mentional locality is approximately 200 miles south-south-east of the type locality. All specimens collected by Cutter were taken in lowland areas, supporting remarks by Commissaris (1960) concerning habitat preferences of _P.

merriami_ as compared with those of the closely related _P. eremicus_.