Notes on distribution and variation in the Mexican big-eared bat, _Plecotus phyllotis_

Southwestern Association of Naturalists Notes on Distribution and Variation in the Mexican Big-Eared Bat, Plecotus phyllotis Author(s): Hugh H. Genoways and J. Knox Jones, Jr. Source: The Southwestern Naturalist, Vol. 12, No. 4 (Dec. 31, 1967), pp. 477-480 Published by: Southwestern Association of Naturalists Stable URL: http://www.jstor.org/stable/3669618 . Accessed: 18/06/2013 07:01 Your use of the JSTOR archive indicates your acceptance of the Terms & Conditions of Use, available at . http://www.jstor.org/page/info/about/policies/terms.jsp . JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact [email protected]. . Southwestern Association of Naturalists is collaborating with JSTOR to digitize, preserve and extend access to The Southwestern Naturalist. http://www.jstor.org This content downloaded from 128.103.149.52 on Tue, 18 Jun 2013 07:01:15 AM All use subject to JSTOR Terms and Conditions Pampa-Borger highway, deep sand prairie along right-of-way, high plains, "very infrequent here, only one clump seen, this collected," M. C. Johnston 6809 (with James W. Walker), 24 Aug. 1961 (LL); Hartley Co., on white sand-clay hills about 8 miles west of Channing, D. S. Correll 30359, 9 Oct. 1964 (LL). This species has previously been known in "Dry hills and sandy plains, South Dakota and Nebraska to Wyoming, New Mexico and Arizona" (A. S. Hitchcock with A. Chase, Man. of the Grasses of the U.S., p. 401, 1950) --The collections and their study represent work on the MANUAL OF THE VASCULAR PLANTS OF TEXAS, co-authored by D. S. Correll and supported by grants (NSF G-15901, GB-572, GB-3138) to Texas Research Foundation.-Marshall C. Johnston, Herbarium and Department of Botany, The University of Texas at Austin; and Research Associate, Texas Research Foundation, Renner. NOTES ON DISTRIBUTION AND VARIATION IN THE MEXICAN BIGEARED BAT, PLECOTUS PHYLLOTIS.-When Handley (1959) revised the American bats of the genus Plecotus, he had but three specimens of Plecotus phyllotis (G. M. Allen, 1916)-two from Mexico and one from Arizona. Subsequent to Handley's work, this uniquely large-eared bat has been recorded from several additional localities in Arizona and from adjacent New Mexico, but has been reported from Mexico only from two places in northern Durango (Gardner, 1965), and one each in Nuevo Le6n (Carter et al., 1966:497) and Distrito Federal (Villa, 1967:427). Six additional Mexican specimens in the collections of the Museum of Natural History, The University of Kansas, from the states of Chihuahua, Jalisco, and Nuevo Le6n, add to our understanding of the distribution of P. phyllotis in Mexico (see Fig. 1) and make possible, when compared with earlier reported material, preliminary remarks on geographic variation in this bat. Previously unreported Mexican localities are listed below; the Jaliscan specimens provide the southwesternmost record for P. phyllotis. 2 mi. S and 5 mi. W San Francisco, 5500 ft., Chihuahua.---A male (KU 73594) was netted over a small pool in rocky Madera Canyon on 26 June 1957 by Sydney Anderson and a party of students. The testes measured 2.5. Six other species of vespertilionids and Tadarida brasiliensis were captured at the same place. Vegetation in the immediate area consisted mostly of cedar, oak, and sycamore; slopes adjacent to the rock-walled canyon were described in field notes as "semi-barren." 5 mi. W Atenquique, 7700 ft., Jalisco.-On the evening of 5 July 1966 one of us (Genoways) and Percy L. Clifton obtained a male (KU 107498) in an area heavily forested with tall trees (mostly pine, but also some oak and a few fir). The bat was trapped in a mist net stretched across a logging trail under low-hanging pine branches. A single Myotis californicus was the only other bat taken in the same net on a cold night (estimated 400 F); rain fell intermittently. Volcdn de Fuego (also known as Volcdn de Colima), 9800 ft., Jalisco.-A male (KU 107499) was captured on the evening of 6 July 1966 under weather conditions similar to those described above. The mist net in which this bat was taken was placed across a narrow road between two old lava flows not far from the base of the active volcano. Bunch grass and a few small shrubs constituted the only vegetation in the immediate vicinity but conifers grew on slopes to the north. No other bats were trapped in this net, even though it was in place for five consecutive nights. A second male (KU 107500) was collected at Volcin de Fuego on the following evening, in a net across a logging road. Forest at this place was composed of tall firs and a few large oaks, all of which supported epiphytes. A thick understory of brush 477 This content downloaded from 128.103.149.52 on Tue, 18 Jun 2013 07:01:15 AM All use subject to JSTOR Terms and Conditions grew to a height of 6-8 feet under the tall trees. Aside from the one big-eared bat, a single Myotis californicus was netted (although other bats were seen) on a night that was clear and cold. Volcin de Fuego, a few miles south of the place 5 mi. W Atenquique, is the southwesternmost locality whence P. phyllotis has been collected and also is the highest in elevation. 3 mi. SW La Escondida, 6300 ft., Nuevo Ledn.--At this place on the night of 31 July-i August 1964, Arturo Jiminez G. and Clifton netted over a small water hole in an area where scattered oak prevailed; a few pines grew on adjacent ridges. Among the bats taken, which included Leptonycteris nivalis, Eptesicus fuscus, Lasiurus borealis, Lasiurus cinereus, and Tadarida brasiliensis, were two P. phyllotis (KU 98548-49), a subadult female and an adult male (testes 4 x 2). External and cranial measurements (in millimeters) of the six specimens mentioned above, in the same order in which they are listed, are as follows: total length, 114, 112, 108, 109, 110, 110; length of tail, 51, 46, 44, 45, 48, 50; length of hind foot, 11, 10, 11, 10, 9, 10; length of ear from notch, 35, 37, 39.5, 37, 41, 41; length of forearm, 45.8, 45.5, 43.8, 41.8, 44.9, 43.9; weight (in grams), 10.0, 11.3, -, -, 11.5, 12.4; greatest length of skull, 17.3, 17.0, 17.2, 16.6, 17.0, 16.8; zygomatic breadth, 9.5, 9.8, -, 9.8, 9.3, 9.7; postorbital constriction, 4.1, 4.0, 4.1, 4.4, 4.0, 4.2; breadth of braincase, 8.9, 8.9, 8.9, 9.1, 8.7, 8.9; length of maxillary toothrow, 5.7, 5.9, 5.8, 5.6, 5.3, 5.6; palatal breadth, 6.5, 6.6, 6.4, 6.6, 6.1, 6.5; postpalatal length, 6.4, 6.5, 6.3, 6.3, 6.4, 6.4. Cranial measurements were taken as described by Handley (1959:98). Handley (op. cit.: 130) compared the one specimen he examined from Arizona with the two available from northeastern Mexico and noted that the Arizonan bat was larger, had a more broadly rounded tragus distally, and was "more pallid throughout." We have studied 25 specimens of phyllotis, 18 from Arizona and one from Durango in addition to the six Mexican specimens discussed above, and have perused the recent literature in which descriptive notes and measurements of other specimens have been recorded. As a result, we note some geographic variation in external and cranial size, slight variation in color, but find no consistent differences in the structure of the tragus or in other features. In color, specimens from the northern part of the range of the species (from northern Durango northward to Arizona) average somewhat paler, both dorsally and ventrally, than do bats from the southern part of the range-paler in the ways mentioned by Handley (loc. cit.). Nevertheless, the differences are slight and of an average nature, and we are unable to distinguish differences in color of ears and membranes in the specimens at hand. In size, we note a slight increase from south (small) to north (large) in at least some external and cranial features (see Fig. 1) except that five individuals examined from Mohave County, Arizona, at the northern limit of the distribution as presently known, reverse the cline and are small. Specimens from eastern and central Mexico and from northwestern Arizona are the smallest, those from elsewhere in Arizona the largest, and bats from other localities generally are intermediate in size. Present evidence does not seem to justify nomenclatorial recognition of more than one taxon in P. phyllotis, and we retain the monotypic arrangement employed by Handley. Judging from the evidence at hand, Plecotus phyllotis is distributed primarily on the Mexican Plateau and in adjacent areas to the northwest in Arizona and western New Mexico. The known altitudinal range of the species varies from 9800 feet in Jalisco northward to 2600 feet (Cockrum and Musgrove, 1964:473) in northwestern Arizona, but the vast majority of known specimens are from altitudes between 3500 and 7500 feet. 478 This content downloaded from 128.103.149.52 on Tue, 18 Jun 2013 07:01:15 AM All use subject to JSTOR Terms and Conditions 114 108 102 SI 68(5) . ---- N 44(~5) 2 I 34 9, 0,7.4(2) I I ??47.00(41 . 47.2(3) 5 17.7(4)-/ " 46.o04f 30 - . ) " ' 45.8(I) i O 030 ( )> ( t,. -,, 26 8 S174(6) ( \ 9 ; "-- 26 'i 17 5(I) ,--- / 9\ 90 3-0 6 9(36.9)2 \~ ~ i. ' -/ ".(2) \,, 16.7(I) 2 \? ./ .- -/. 44.0( 1 L .-) Scale in Miles 3 3 -1..f-I, 8 , i 0 108 102 Fig. 1. Records of occurrence of Plecotus phyllotis outlining the general distribution of the species. Greatest length of skull and length of forearm (sample sizes in parentheses) are indicated. Numbers for localities correspond with those listed in text. Solid symbols indicate localities whence specimens have been examined; open symbols represent specimens recorded in the literature. Localities from which specimens were examined, and those cited from the literature for which measurements are recorded in Fig. 1, are identified on the map by the same number under which they are listed below. Where one symbol on the map represents several points of occurrence, the one listed first after the parenthetical number is the point plotted on Fig. 1. In addition to specimens in the Museum 479 This content downloaded from 128.103.149.52 on Tue, 18 Jun 2013 07:01:15 AM All use subject to JSTOR Terms and Conditions of Natural History (KU), we have examined some from the collections of the University of Arizona (UA), the loan of which was arranged by E. L. Cockrum. ARIZONA. Mohave County: (1) 1 mi. S Union Pass, 4 (UA); 2 mi. W Union Pass, 2 (UA); vicinity Pipe Springs National Monument, 5000 ft., 1 (UA). Coconino County: (2) 28 mi. S, 9 mi. E Flagstaff (see Findley and Jones, 1961:97). Gila County: (3) Wilbanks' Ranch, Sierra Ancha, 7200 ft., 4 (KU). Graham County: (4) Oak Grove Canyon, 1 mi. N, 6/ mi. W Klondyke, 3550 ft., 3 (UA). Cochise County: (5) 1 mi. WNW Portal, 4900 ft., 2 (1 KU, 1 UA); 31 mi. SW Portal, 5500 ft., 1 (KU); S fork Cave Creek, 5400 ft., 1 (UA). NEW MEXICO. Catron County: (6) 9 mi. E Mogollon, 7800 ft., and other nearby localities (see Jones, 1961:538-539). MEXICO. Chihuahua (7-see text). Durango: (8) Navarro, 6100 ft., 1 (UA)- see also Gardner (1965:105) for measurements of additional specimens from Navarro and one from nearby Presa de Ojito. Nuevo Leon: (9) 17 mi. SW Monterrey, 4500 ft. (Carter et al., 1966:497); (10) 3 mi. SW La Escondida (see text). Tamaulipas: (11) Miquihauna (Handley, 1959:131). San Luis Potosi: (12) probably near San Luis Potosi (Handley, 1959:131). Jalisco (13-see text). Distrito Federal: (14) Ciudad Universitaria, 2250 m. (Villa, 1967:427). LITERATURE CITED CARTER, D. C., R. H. PINE, and W. B. DAVIS. 1966. Notes on Middle American bats. S. W. Nat. 11: 488-499, December 31. COCKRUM, E. L., and B. F. MUSGROVE. 1964. Additional records of the Mexican big-eared bat, Plecotus phyllotis (Allen), from Arizona. J. Mammal. 45: 472474, September 15. FINDLEY, J. S., and C. JONES. 1961. New United States record of the Mexican big-eared bat. J. Mammal. 42: 97, February 20. GARDNER, A. L. 1965. New bat records from the Mexican state of Durango. Proc. Western Foundation Vert. Zool. 1: 101-106, June. HANDLEY, C. O., JR. 1959. A revision of American bats of the genera Euderma and Plecotus. Proc. U.S. Nat. Mus. 110: 95-246, 27 figs., September 3. JONES, C. J. 1961. Additional records of bats in New Mexico. J. Mammal. 42: 538-539, November 20. VILLA-R., B. 1967. Los murcidlagos de M~xico. Inst. Biol., Univ. Mexico, xvi -491 pp., illustrated, February 6. Hugh H. Genoways and J. Knox Jones, Jr., Museum of Natural History, The University of Kansas, Lawrence. SWIMMING ABILITY IN POCKET MICE.-Little has been recorded concerning swimming ability in mammals. Noteable exceptions are Kennerly's (S.W. Nat. 8: 85-88, 1963) and Sheppe's (J. Mammal. 46: 336-337, 1965) studies of Geomys bursarius and Peromyscus leucopus respectively. Perusal of the literature revealed a single report of swimming in pocket mice (see Davis, J. Mammal. 23: 99, 1943). To our knowledge, there have been no studies designed to compare the swimming ability of closely related species and relate such ability to dispersal potential and geographic distribution. The purpose of our studies were to determine: (1) whether or not Perognathus 480 This content downloaded from 128.103.149.52 on Tue, 18 Jun 2013 07:01:15 AM All use subject to JSTOR Terms and Conditions