Cladistical Analysis of G-Banded Chromosomes of Nectar Feeding Bats (Glossophaginae: Phyllostomidae)

Haiduk, M. W.,and R. J . Baker (Department of Biological Sciences and The Museum, Texas Tech University, Lubbock, Texas 79409) 1982. Cladistical analysis of G-banded chromosomes i n nectar feeding bats (Glossophaginae: Phyllostomidae). Syst . Zool., 31 :252-265.-Differentially stained chromosomes, when analyzed in a cladistic framework, provide a systematic hypothesis for ten glossophagine genera. Two separate groups are recognized on the basis of chromosomal data; a chromosomally conservative or plesiomorphic group consisting of Glossophaga, Monophyllus, Leptonycteris, and the brachyphyllines, and a relatively rapidly evolving derived group consisting o fdnoura , Lonchophylla, Lionycteris, Choeroniscus, Choeronycteris, Hylonycteris, and Musonycteris. Among the six genera characterized as slowly evolving, only a single rearrangement has been identified, whereas, among the seven genera characierized as rapidly evolving over 100 chromosomal rearrangements are required to explain the observed variation. Such a contrast in rate and type of chromosomal evolution is difficult to explain in terms of most currently accepted theories,,of chromosomal evolution and the pattern of change is most like "karyotypic megaevolution. Within the derived group, cladistic relationships are resolved to the generic level. Variation in the magnitude of evolution at the morphological and chromosomal levels is such that chromosomal data are useful for the resolution of relationships among genera, whereas, morphological data are more informative at the subfamilial level. A combination of the two data sets is compatible with the hypothesis that the Glossophaginae is monophyletic and provides a better understanding of the nature of evolution within this subfamily. [Glossophagines; chromosomal evolution; phylogeny; cladistics; G-banding.] The Glossophaginae (Phyllostomidae: reduced diploid and fundamental numChiroptera) is an assemblage of 13 genera bers. Baker (1967) concluded that this which due to their shared morphological group possibly represented an indepenadaptations to a nectarivorous feeding dently derived lineage related to the Carmode has been recognized as a unit since olliinae. Stock (1975), however, studied Miller (1907). More recently, however, G-banded chromosomes and demonstratdata from chromosomal (Baker, 1967, ed that little or no chromosomal homol1970; Gardner, 1977), immunological ogy was shared between Choeronycteris (Gerber and Leone, 1971), and morphoand Carollia. logical (Phillips, 1971; Griffiths, 1982) Two subgroups were also recognized studies have led to several alternative within the Glossophaginae by Phillips proposals indicating a polyphyletic ori(1971) and Gerber and Leone (1971). gin of the subfamily. Phillips, based primarily on an analysis Baker (1967) recognized two general of dental characters, suggested that the subgroups within the Glossophaginae on Glossophaga group was more closely althe basis of nondifferentially stained lied with Macrotus and Artibeus, wherechromosomes. One group was characteras, the Choeronycteris group was possiized as having diploid numbers (2n) near bly derived from the phyllostomines. 32 and fundamental numbers (FN) near Gerber and Leone (1971) recognized the 60, and was believed to be closely allied same groupings but their analysis of sewith phyllostomine taxa. The other group rum immunology suggested that the consisted of Choeroniscus and ChoeroGlossophaga group was more closely renycteris and characteristically possessed lated to the Carolliinae, whereas, the 1982 GLOSSOPHAGINE EVOLUTION 253 Choeronycteris group was allied with the Phyllostominae. Gardner (1977) examined nondifferentially stained chromosomes of additional taxa within the Glossophaginae and recognized essentially the same grouping as that proposed by Phillips (1971). However, Gardner enlarged the Choeronycteris group to include Lionycteris, Lonchophylla, Lichonycteris, Hylonycteris, Platalina, and Scleronycteris, whereas, all of these taxa were included in the Glossophaga group by Phillips (1971). Additionally, Gardner proposed that if the Glossophaginae is monophyletic, then Lonchophylla thomasi represented the probable primitive form chromosomally, but polyphyly was not eliminated as an alternative hypothesis. Baker et al. (1981) provided data sets based on electrophoretic and immunological studies. These authors concluded that the polyphyletic branching proposed by Baker (1967) was incorrect. The study of Baker et al. (1981) also suggests that the relationship between glossophagines and brachyphyllines is sufficiently close that the subfamilies form a single clade with a shared common ancestry. This is compatible with the conclusion that relative to the primitive karyotype for the phyllostomids, Glossophaga, Monoplzyllus, Phyllonycteris, Erophylla, and Brachyphylla all share identical derived Gand C-banded karyotypes (Baker and Bass, 1979). The findings of Baker and Bass (1979) and Baker et al. (1981) were compatible with the data on uterine histomorphology (Hood and Smith, 1983) which indicated that the brachyphyllines, glossophagines, and stenodermatines formed a clade within the Phyllostomidae. The brachyphyllines and glossophagines shared identical uterine morphology, and this prevented further resolution of the relationships between and within these taxa (Hood and Smith, 1983). A conflicting result was obtained by Griffiths (1982) from a comparative study of lingual and hyoid musculature. On the basis of his study, Griffiths (1982) split the Brachyphyllinae-Glossophaginaeassemblage into four subfamilies. The Glossophaginae wak recognized to consist of Glossophaga, Monophyllus, Lichonycteris, Leptonycteris, Anoura, Hylonycteris, Scleronycteris, Choeroniscus, Choeronycteris, and Musonycteris. The Lonchophyllinae was established to include Lonchophylla, Lionycteris, and Platalina, and the Brachyphyllinae was split into two subfamilies, the Brachyphyllinae to include only Brachyphylla and the Phyllonycterinae to include Phyllonycteris and Erophylla. Additionally, Griffiths concluded that the Lonchophyllinae was an independent lineage only distantly related to the other three subfamilies. A review of Systematic Zoology over the past few years reveals that systematic theory has advanced rapidly. However, few papers dealing with hard data sets have maximally utilized these advances to provide a better systematic classification. From the above discussion on the divergent interpretations of data for the nectarivorous leaf-nosed taxa, it is obvious that providing a classification compatible with modern systematic theory will be no small challenge. In this study, G-banded chromosomal data are presented for nine additional genera of glossophagines representing every major subdivision of the subfamily recognized by previous authors. These data are used in a cladistical framework to assess relationships between genera, and to address the questions of a polyphyletic origin of the Glossophaginae and a workable systematic arrangement for the