Chromosomal Variation in Vampyressa and a Review of Chromosomal Evolution in the Phyllostomidae (Chiroptera)

Abstract

Gardner, A. L. (National Fish and Wildlife Laboratory, Fish and Wildlife Service, National Museum of Natural History, Washington, D.C. 20560) 1977. Chromosomal variation in Vampyressa and a review of chromosomal evolution in the Phyllostomidae (Chiroptera). Syst. Zool., 26:300-318.-Comparisons of the karyotypes of the species of Vampyressa suggest two modes of chromosomal rearrangements in the derivation of the Vampyressa karyotypes: pericentric inversions in V. brocki, V. nymphaea, and V. bidens; and translocations (fusions) in V. melissa and the variants of V. pusilla. This Vampyressa phylogenetic model was used to evaluate the possible derivations of the chromosomal patterns of the 97 species of phyllostomid bats whose karyotypes are known. Sufficient variation to indicate probable evolutionary patterns, in addition to that outlined for Vampyressa, was found at the species level for Micronycteris and Tonatia, and at the generic level for the Glossophaginae, Carolliinae, and Stenoderminae. The analysis supports the points of view presented herein that (1) the common (often considered the ancestral) 2n = 32, FN = 60 configuration was independently acquired by three or more evohitionary lineages and, therefore, must be considered to be derived; (2) the primitive phyllostomid karyotype had a high diploid number (near 40, but possibly as high as 46) and a low fundamental number (near minimum); (3) there was a general trend toward reduction in diploid numbers concomitant with maximization of fundamental numbers; and (4) totally biarmed autosomal configurations, which characterize the majority of the Phyllostomidae, are comparatively more stable than those karyotypes in which half or more of the autosomes are uniarmed. Fourteen karyotypes are reported here for the first time, including that of Vampyressa melissa, which has the lowest diploid number known in the Chiroptera (2n = 14). [Phyllostomidae; evolution; karyotypes.] As presently understood, Vampyressa contains five species (Peterson, 1968). Karyotypically, these five demonstrate sufficient variation to permit not only an evaluation of chromosomal evolution within the genus but insight into the karotypic origins and the directions and kinds of chromosomal change that may have occurred within the family Phyllostomidae. This analysis is based on chromosomal material processed in the field as well as on published karyotype descriptions. Field prepared material was processed by the colchicine-hypotonic citrate technique outlined by Patton (1967). Chromosomal morphology and fundamental number (FN) are as defined by Patton (1967). The specimens whose chromosomes are described herein for the first time are deposited in the collections of the Louisiana State University Museum of Zoology (LSUMZ), the Museum of Vertebrate Zoology, University of California, Berkeley (MVZ), and the National Museum of Natural History (USNM) as indicated in Table 1. KARYOTYPES OF Vampyressa Of the Vampyressa karyotypes discussed here, the V. melissa and V. bidens karyotypes and the V. pusilla variant from Peru have not been described previously. Vampyressa pusilla.-Two geographically distinctive chromosomal variants are known (Baker et al., 1973) and a third from Peru is described as follows: 2n =22 (&), 23 (9); FN=22 (Fig. 1, B and C). Autosomes: 1 unpaired large metacentric and 9 pairs of medium-sized to small acrocentrics. The female has an additional pair of autosomes, the smallest in the complement, here considered to be acrocentric for the determination of FN although each bears a very short second arm. The male possesses an unpaired acrocentric (designated XA in Fig. 1C), which for descrip-