Taxonomic Notes on Mexican Bats of the
Genus Rhogeëssa

BY

E. RAYMOND HALL

University of Kansas Publications
Museum of Natural History

Volume 5, No. 15, pp. 227-232
April 10, 1952

University of Kansas
LAWRENCE
1952

University of Kansas Publications, Museum of Natural History

Editors: E. Raymond Hall, Chairman, A. Byron Leonard,
Edward H. Taylor, Robert W. Wilson

Volume 5, No. 15, pp. 227-232
April 10, 1952

University of Kansas
Lawrence, Kansas

PRINTED BY
FERD VOILAND, JR., STATE PRINTER
TOPEKA, KANSAS
1952

24-1780

Taxonomic Notes on Mexican Bats of the
Genus Rhogeëssa

BY
E. RAYMOND HALL

Five skins with skulls of Rhogeëssa , collected by J. R. Alcorn in the states of Sonora and Nayarit of western Mexico, were recently received at the Museum of Natural History of the University of Kansas. Two other specimens of the same genus, collected by Walter W. Dalquest in the state of Veracruz of eastern Mexico, also are in the Museum of Natural History. With the aim of applying names to these bats they were compared with materials in the United States National Museum (including the Biological Surveys collection) where there are approximately the same number of Mexican specimens of Rhogeëssa as are in the Museum of Natural History.

The three kinds of Rhogeëssa named from Mexico are as follows: R. parvula from the Tres Marias Islands off the west coast of Nayarit; R. tumida from Mirador, Veracruz, on the eastern slope of the Republic; and R. gracilis from Piaxtla, Puebla, on the southern end of the Mexican Plateau.

Of Rhogeëssa gracilis Miller (N. Amer. Fauna, 13:126, October 16, 1897) only three specimens are known; two are from Piaxtla, Puebla, and the third is from the Isthmus of Tehuantepec. Only the specimen from the Isthmus has a complete skull. The broken skull of the holotype is partly separated from the skin of the head and in such a manner as to reveal the teeth. The skull of the holotype seems to be broader (relative to its length) across the mastoids and posterior parts of the zygomata than in R. tumida or than in R. parvula . My comparisons indicate that Rhogeëssa gracilis has larger (longer and wider) ears than R. parvula and R. tumida and that it is specifically distinct from the two last mentioned kinds.

The two other nominal species from Mexico, R. parvula and R. tumida , were named and described by Harrison Allen (Proc. Acad. Nat. Sci. Philadelphia, 1866: 285 and 286, respectively) on the basis of three specimens in the United States National Museum. Two were from the Tres Marias Islands and were the basis of the name R. parvula ; the third was from Mirador, Veracruz, and was the basis [Pg 230] of the name R. tumida . These specimens seem to have been preserved in alcohol. I have examined the skulls of two of these. One (U.S.N.M., new number 37329, old number 7842) is alleged to be the paratype of R. parvula and the other (U.S.N.M., 84021) is alleged to be the holotype of R. tumida . In the glass vial containing skull No. 84021, there is a label in the handwriting of Gerrit S. Miller, Jr., bearing the following information: "In the orig. descr. the number of this sp. is said to be 8195. This is an error. Specimen catalogued 3.1.98 G.S.M. Jr." On the back of a second label in the skull vial there is written, "There is no doubt that this is the type skull. It was returned by H. A. with no. given in orig. descr. G.S.M. Jr." In the catalogue of the U. S. National Museum there is the statement that the type of Rhogeëssa tumida was collected by H. A. Grayson.

The name Rhogeëssa parvula was based on two specimens (Smithsonian Institution Nos. 7841 the type and 7842, in alcohol, collected by Col. Grayson in the Tres Marias Islands off the west coast of Mexico.) The type seems never to have been returned from the Academy of Sciences of Philadelphia to the U. S. National Museum in Washington, D. C., and cannot (in 1951) be found in Philadelphia or anywhere else. The skull, but no other part, of the second specimen is in the United States National Museum under the catalogue number 37329 (old No. 7842). The skull has been broken in two through the interorbital region but is glued together.

Of R. tumida , no additional specimen has been saved, so far as I know, from the type locality, Mirador, Veracruz.

Of R. parvula , Nelson and Goldman, on May 19, 1897, on María Madre Island, saved in alcohol an additional specimen (92413 U.S.N.M.) from which J. Biggs, Preparator at the National Museum, in 1951, removed and cleaned the skull. In small size and in all other features, the skull of 92413 closely resembles those of specimens saved by Alcorn from the adjoining mainland of Mexico in Sonora and Nayarit. The pelage of the upper parts of 92413 could be described as "of a light greyish-brown at basal third, fawn-chestnut-brown at apical two-thirds" which are the words that H. Allen ( op. cit. : 285) used to describe the pelage of his R. parvula . The external measurements of 92413 are: total length, 60; length of tail, 25; length of hind foot, 5.5; and ear from notch, 11.0. The first two measurements are slightly smaller than the corresponding measurements of any other specimen seen. Nevertheless, the measurements (tail, 30.5; hind foot, 5.3 [after H. Allen, orig. descr.]) of the [Pg 231] holotype of R. parvula , also from the Tres Marias Islands, show that it was as large as no. 39724 from the adjoining mainland (see table 1).

According to the original descriptions, R. parvula and R. tumida differ in size, R. parvula being the smaller. As may be seen from table 1, the alleged type of R. tumida and the alleged paratype of R. parvula indicate the opposite! All specimens obtained since the time of the original descriptions, as may be seen by inspecting table 1, support the correctness of the original descriptions. Therefore, and also because of the other information presented above, I am inclined to the opinion that the holotype of R. tumida and the paratype of R. parvula have been switched; each now is associated with the name and data, at least for locality, of the other.

Other opinions are that Rhogeëssa from the Tres Marias Islands average smaller than Rhogeëssa of the adjoining mainland of western Mexico but not enough smaller to warrant subspecific separation of the two. Specimens from places geographically intermediate between the geographic ranges, as now known, of R. parvula and R. tumida probably will reveal intergradation between the two kinds, which, therefore, should stand as subspecies of a single species.

As understood now, the Mexican Rhogeëssa are as follows:

Transmitted November 30, 1951.

TABLE LEGEND
Column FO: Forearm
Column GR: Greatest length of skull including teeth
Column CO: Condylobasal length (not including teeth)
Column LE: Length of upper tooth-row, C1-M3
Column ZY: Zygomatic breadth
Column MA: Mastoid breadth
Column BR: Breadth across upper molars

Transcriber's Notes:
Standardized Punctuation.
Left inconsistent usage of accents.
Page 229: Changed Ishtmus to Isthmus.
Footnote A: Changed Natoinal to National