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PROCEEDINGS OF THE UNITED STATES NATIONAL MUSEUM Issued vM^iS^yv'^'l ^H ^ SMITHSONIAN INSTITUTION U.S. NATIONAL MUSEUM Vol. 110 Washington : 1959 No. 3417 A REVISION OF AMERICAN BATS OF THE GENERA EUDERMA AND PLECOTUS By Charles O. Handley, Jr. Introduction Confusion and damage to nomenclatural stability are consequences of taxonomic revisions that do not provide adequate explanations or justifications for proposed changes in nomenclature. They are ig- nored, accepted with reservation, or blindly followed by those who have occasion to use them. Confusion of this sort involves a wide- spread American bat, now referred to in literature either as Cory- norhinus or Plecotus. The purpose of this paper is to clarify the status of this bat and its American and Eurasian relatives (particularly Euderma), to assay the evolution of the group, to map geographic distributions, and to bring together the Uterature on natural history of the group. The genera Euderma and Plecotus are vespertilionid bats with ex- ceptionally large ears. They are known colloquially as mule-eared bats, jack-rabbit bats, or, simply, big-eared bats, or long-eared bats. Some species are referred to as lump-nosed bats. Plecotus, as here understood, includes the American Idionycteris and Corynorhinus as subgenera. Perhaps the earliest published reference to an American big-eared bat was that of Clayton (1694, p. 124) in his remarks on the "beasts of Virginia": "Baits, as I remember at least two sorts; one a large 95 96 PROCEEDINGS OF THE NATIONAL MUSEUM vol. ho sort with long Ears, and particularly long stragling hairs. The other much like the English, something larger I think, very common." There is now an extensive American literature on Euderma and Plecotus, but most reports contain little more than records of speci- mens. The only revisionary works have been those of H. Allen (1864, 1894), Miller (1897), and G. Allen (1916). Most of our knowledge of the anatomy and physiology of the gi"Oup is included in the papers of Larsell and Dow (1935) and Pearson, Koford, and Pearson (1952). The few life history studies are generally superficial; those of Dalquest (1947), Pearson, et al. (1952), and Twente (1955) are notable excep- tions. Much yet remains to be learned about Euderma and the Ameri- can populations of Plecotus. These bats occur in most temperate portions of the Northern Hemisphere. They are generally scarce. In America, Euderma is known by 16 specimens, the subgenus Idionyeteris is known by less than a dozen specimens, all but two of them collected since 1955; and perhaps no other North American bat with such an extensive geo- graphic range as the subgenus Corynorhinus has been collected so in- frequently. Species of the latter subgenus are known to occur from the Atlantic to the Pacific and from Canada to the Isthmus of Tehuan- tepec in Mexico. This wide geographic range is deceptive, however, for these bats display narrow limits of tolerance in their choice of habitat. Within the bounds of their ranges are large areas in which they apparently do not occur, and others in which they occur only sparingly. There are few areas in which they are common. Materials The scarcity of Euderma and Plecotus in America is evident from the small number of museum specimens listed in the early reviews. H. Allen's 1864 monograph included only 18 specimens, and his 1894 monograph only 19. For Miller's 1897 revision, 43 examples were available. G. Allen's 1916 review was based on a total of 126 speci- mens. The material from which I have drawn my conclusions concerning these bats consists of four dry skins and skulls and a single specimen preserved in alcohol representing Euderma; three specimens of the subgenus Idionyeteris, dry skins and skulls; 25 dry skins and skulls, two skeletons, and 32 specimens preserved in alcohol, representing at least five races of the subgenus Plecotus; and about 800 specimens (see species accounts for type of preservation) representing all the named forms of the subgenus Corynorhinus. In the course of the study I have examined enough specimens to define Euderma and American Plecotus, but have not attempted to assemble aU available specimens. Those examined are in the collec- tions of the following: AMERICAN BATS—^HANDLEY 47 American Museum of Natural History Ohio State Museum (OSM) (AMNH) School of Tropical and Preventive Albert Schwartz (private collection) Medicine, Loma Linda, Calif. (AS) (STPM) California Institute of Technology Texas A. & M. College (Texas Co- (CIT) operative Wildlife Collection) Carlsbad Caverns National Park (CC) (TCWC) Charleston (South Carolina) Museum Texas State Department of Health, (ChM) Austin, Tex. (TSDH) Carnegie Museum (CM) Texas Technological College (TT) Chicago Natural History Museum (CNHM) University of Arkansas Department of Zoology (UAZ) W. Gene Frum (private collection) University of Illinois Museum of Nat- (GF) ural History (UI) Instituto de Biologia, Universidad Na- University of Kentucky Zoology cional Aut6noma de Mexico (IB) De- partment (UK) Illinois Natural History Survey (INHS) University of Michigan Museum of University of Kansas Museum of Zoology (UMMZ) Natural History (KU) University of Oklahoma Museum of Louisiana State University Museum Zoology (UOMZ) of Zoology (LSU) U.S. National Museum (including Harvard University Museum of Com- U.S. Fish and Wildlife Service's parative Zoology (MCZ) Biological Surveys collection) University of California Museum of (USNM) Vertebrate Zoology (MVZ) University of Utah Museum of Zool- Oklahoma A. & M. College (0AM) ogy (UU) I express sincere thanks and appreciation to the owners of private collections and to the museum authorities who kindly loaned speci- mens for my study. To those at the American Museum of Natural History and at the Museum of Comparative Zoology, Harvard Univer- sity, I am particularly grateful. I am indebted to Seth B. Benson, Museum of Vertebrate Zoology, University of California, and to Rollin H. Baker and E. Raymond Hall, Museum of Natural History, University of Kansas, for the loan of specimens set aside for their personal study. Special thanks are due to John A. Sealander, Univer- sity of Arkansas, for allowing me to utilize specimens under his care in the description of a new subspecies, and for his kindness in depositing the type specimen in the U.S. National Museum; and to Aurelio Malaga Alba, Pan American Sanitary Bureau, for his cooperation in securing much needed Mexican specimens, one of which has served as the type of a new subspecies. The Fish and Wildlife Service, U.S. Department of the Interior, has generously allowed me to utilize from its files the unpublished field notes of its collectors. The following individuals contributed information and other assist- ance for which I am grateful: R. W. Barbour, F. L. Burnett, W. W. Dalquest, W. G. Frum, A. F. Ganier, Helen Gaylord, B. P. Glass, Woodrow Goodpaster, R. M. Goslin, Iracy O. Handley, R. H. Hand- : : 98 PROCEEDINGS OF THE NATIONAL MUSEUM vol. no ley, H. B. Hitchcock, Patricia Isham, E. V. Komarek, Barbara Lawrence, R. E. Mumford, Thelma Reid, C. C. Sanborn, William Schaldach, Jr., Albert Schwartz, P. M. Smith, P. W. Smith, Ai-thur Stupka, Robert Traub, Bernardo Villa R., and F. N. Young. I am thankful to the persons who reviewed the manuscript and offered helpful criticism and advice: A. M. Elliott, C. W. Hibbard, E. T. Hooper, Remington Kellogg, D. H. Johnson, H. W. Setzer, A. H. Smith, and C. F. Walker. Methods In tables 7-18 cranial and external measurements, in millimeters, are given for Euderma maculatum, Plecotus auritus, Plecofus phyllotis, and for all the races of the subgenus Corynorhinus. Females are significantly larger than males in these bats. Accordingly, measure- ments for the two sexes are tabulated separately. Only adults, as determined by ossification of the linger joints and appearance of the skull, were measured. Measurements of Euderma are from the following sources : Ashcraft (1932, p. 162), Durrant (1952, pp. 59, 66), Nicholson (1950, p. 197), Parker (1952, p. 480), Stager (1957, p. 260), and four specimens measured by me. External measiu-ements of Plecotus, except of the forearm, are those taken by the collectors. I measured the forearm (greatest length of radius-ulna including carpals) on the preserved specimens . All cranial measurements (fig. 1) were taken with dial calipers and the aid of a binocular microscope in the following manner Greatest length: Distance, on the diagonal, from the anteriormost border of the premaxilla to the posterior limit of the supraoccipital; incisors are excluded. Zygomatic breadth: Greatest distance between the outer borders of the zygomatic arches. Interorbital breadth: Least diameter of the interorbital constriction of the front als. Brain case breadth: Distance, measured above the auditory bullae, between the lateral limits of the parietals. Brain case depth: Distance between the dorsal extreme of the skull and the ventral limit of the occipitosphenoid plate; auditory bullae are excluded. One bar of the caMpers lies flat on the occipitosphenoid plate; the other is in contact with the top of the brain case. Maxillary tooth row: Distance between the anterior edge of the canine and the posterior border of the third molar. Postpalatal length: Distance from the anterior limit of the mesopterygoid fossa to the ventral lip of the foramen magnum. ^. Palatal breadth : Distance between the lateral extremes of M Presence or absence of a secondary cusp in I ^ was indexed according to the following scale (fig. 2) Y AMERICAN BATS—HANDLE 09 0, Secondary cusp absent; no trace. 1, Secondary cusp incipient, in the form of a shoulder, not separated from primary cusp by a notch. 2, Secondary cusp present, separated from primary cusp by a notch. Frequently, the degree of development of the secondary cusp of I^ is not the same on both sides. When absent in one tooth and incipient in the other, it was indexed as 0.5; when absent in one and present in the other, as 1; when incipient in one and present in the other, as 1.5; etc.