Hesperoptenus, Peters, 1868

Hesperoptenus View in CoL Subgenus Milithronycteris is

Rendered Paraphyletic

Based on some morphological differences between the type species of the genus Hesperoptenus , H. doriae , and the other three Hesperoptenus species known at that time, Hill (1976) proposed the subgenus Milithronycteris for H. blanfordi , H. tomesi and H. tickelli , with H. tickelli as type species. More recently, the species H. gaskelli was also included into the new subgenus ( Hill, 1983).

Among other morphological characters the following cranial features were described as characteristic for this subgenus: a broad and elongate braincase, a supraorbitally expanded rostrum and an outer upper incisor (i 3) which is lying behind the inner tooth (i 2) ( Hill, 1976). Although the larger species H. tomesi and H. tickelli were judged as more closely related because they differ quite sharply in a number of features from the much smaller H. blanfordi , all three species were united in Milithronycteris ( Hill, 1976) .

Comparative cytogenetic analysis in the species H. blanfordi , H. tomesi and H. doriae revealed many common features between H. tomesi and H. doriae despite different diploid numbers (this report, Volleth et al., 2023), but a profoundly different karyotype composition to that found in H. blanfordi (this study, Volleth et al., 2001). Similarly, a close relationship between H. tomesi , H. doriae and H. tickelli was found by cyt b and COI sequence comparison, again rendering H. blanfordi as the most distantly related species. As a consequence, the subgenus Milithronycteris must be judged as paraphyletic. We therefore propose to synonymize the subgenus Milithronycteris with the subgenus Hesperoptenus . Despite large karyological differences, the unique structure of the MMY13 homolog, detected in all Hesperoptenus species studied, may serve as synapomorphic character for the genus. Furthermore, Hassanin et al. (2018), in a comparative study of four nuclear genes, detected a shared derived character, a deletion in the gene HDAC2, in both species studied, H. blanfordi and H. tickelli . For these reasons, we refrain from establishing a new (sub)genus for H. blanfordi despite the presence of distinct morphological characters, as for instance adhesive pads on the thumbs, which are missing in the other congeners.

Conclusions

Two different genetic data sets, karyological characters and mtDNA sequences, point to a close relationship between H. tomesi and H. doriae . As a consequence, the subgenus Milithronycteris is rendered as paraphyletic and should be synonymized with the subgenus Hesperoptenus .