Banded Karyotypes of 11 Species of American Bats (<i>Genus Myotis</i>)

Abstract

The vespertilionid bat genus Myotis is among the most speciose of mammalian genera. It is comprised of some 68 species (Anderson and Jones 1967) and is found on virtually all major land masses of the world and in a wide variety of ecological situations. These bats are mostly insectivorous although at least one, Myotis (Pizonyx) vivesi, is a fish eater.Although there is a considerable volume of literature on the ecology, natural history, and behavior of the members of this genus, the systematic and phylogene tic relationships of many of the species remain poorly understood. Miller and Allen's (1928) revision is still the most complete work available for American Myotis. More recently LaVal (1973) has revised the Neotropical species, and Findley (1972) studied phenetic relationships on a world-wide basis.Karyotypic studies have failed to shed much light on intrageneric relationships due to the conservative nature of the Myotis karyotype in that all species studied to date appear to possess 2n=44. This paper reports the chromosomal banding patterns for approximately two-thirds of the recognized species of Myotis that occur in North America. Standard karyotypes have been reported for nine species used in this study: M. sodalis, M. grisescens, M. austroriparius, M. yumanensis, M. velifer, M. keenii, M. evotis, M. thysanodes, and M. nigricans (Baker and Patton 1967). The karyotypes of M. auriculus and M. keaysi are reported for the first time. In addition, the karyotypes for males of M. thysanodes and M. keenii have not been recorded previously. Chromosomal variation and its phylogenetic significance is discussed and a system of nomenclature for the banded chromosomes of vespertilionids is presented. Materials and methodsBats were collected from natural populations and tissue explants of lung or ear were taken at field stations. Fibroblast cultures were established, the cells grown in plastic flasks using Ham's F-10 medium fortified with 8 precent fetal calf serum. Velban (0.025 percent) was added to actively dividing cultures at a rate of .3ml to 10ml growth medium. After 10 minutes, the cells were removed from the flask with trypsin and treated with hypotonic solution (one part growth

Molecular Phylogenetics of the Chiropteran Family Vespertilionidae

“…They studied a rather thorough taxonomic sample (primarily Old World members), including all putative subfamilies, and employed explicit methods for phylogenetic analysis. Furthermore, chiropteran karyotypes are conservative at the genus level and seem especially useful for inferring inter-generic relationships of bats (Baker, 1970;Bickham, 1979aBickham, , 1979bZima and Horáèek, 1985;Volleth and Heller, 1994b). Accordingly, others also have pointed to the study as positive evidence for including Miniopterus within Vespertilionidae (e.g., Simmons, 2000: 3334).…”

“…As a result, classical inferences of species relationships have been difficult. Karyotypic studies have been of little help as well because Myotis is one of the most karyotypically conservative genera within Vespertilionidae (2N = 44, FN = 5052;Bickham 1979aBickham , 1979bBickham et al, 1986;McBee et al, 1986).…”

Pericentric satellite DNA sequences in Pipistrellus pipistrellus (Vespertilionidae; Chiroptera)

“…However, C-banding studies have demonstrated the presence of pericentromeric heterochromatic regions in most karyotypes of bat species analysed to date, with similar size to those described in most of the mammal species (Pathak et al, 1973;Bickham, 1979;Haiduk et al, 1981;Morielle-Versute et al, 1996;Santos and Souza, 1998;Volleth et al, 1999;Volleth et al, 2001).…”

Karyological Analysis and Morphometrics of Horsfield's Bat, <i>Myotis horsfieldii</i> (Chiroptera, Vespertilionidae)

“…Extensive karyological analyses of Vespertilionidae species have been undertaken (Zima and Horacek 1985), with GTG-banding technique karyotypes available for most genera (Bickham 1979a, b, 1987, Zima 1982, Fedyk and Ruprecht 1983, Stock 1983, Harada 1988, Volleth and Tidemann 1989, 1991, Zima et al 1989, Volleth 1992, Volleth and Heller 1994, Volleth et al 2001, Kearney et al 2002. Some researchers have suggested the 2n=44 karyotype of genus Myotis as the ancestral vespertilionid karyotype based on fossil records and primitive morphology of the genus Myotis (Capanna and Civitelli 1970, Andō et al 1977, Bickham 1979b, Baker et al 1985, Zima 1982.…”

“…Others have preferred a 2n=50 ancestral karyotype similar to the genus Eptesicus karyotype that consists of acrocentric autosomes (Fedyk andRuprecht 1983, Stock 1983). GTGbanding comparisons have suggested chromosomal homologies among various species of the family Vespertilionidae (Bickham 1979a, b, 1987, Baker et al 1985, Volleth and Heller 1994, Volleth et al 2001. Robertsonian fusions or centric fusions are proposed as the major chromosomal rearrangements that have occurred during the karyotype evolution of the vespertilionid (Bickham 1979b, Baker et al 1985, Volleth and Heller 1994, Volleth et al 2001.…”