标题：Auditory features and affinities of the Eocene bats Icaronycteris and Palaeochiropteryx (Microchiroptera, incertae sedis) / Michael J. Novacek. American Museum novitates ; no. 2877
摘要："The earliest known bats are skeletons of Icaronycteris index from the early Eocene of western Wyoming and a few less well-represented species from the early Eocene of France. Also known are Palaeochiropteryx tupaiodon and several other species from the middle Eocene of western Germany. These taxa have been regarded as primitive forms, either 'ancestral' to echolocating microchiropterans or 'ancestral' to both micro- and megachiropterans. Details of basicranial structure suggest that these Eocene forms were, however, specialized echolocators comparable to Recent microchiropterans. Moreover, quantitative analysis reveals that the Eocene bats have a more pronounced expansion of the cochlea than many Recent microchiropteran species. There is clear justification for reference of Icaronycteris and Palaeochiropteryx to the Microchiroptera. Conversely, there is no reason to recognize a 'primitive-ancestral' group, Eochiroptera, that is excluded from Microchiroptera or Megachiroptera. The relationships of Icaronycteris and Palaeochiropteryx within Microchiroptera remain uncertain. Association of these taxa and several other Eocene forms within the microchiropteran superfamily Palaeochiropterygoidea fails to clarify these relationships. Palaeochiropterygoidea has not been defined by derived characters, and Icaronycteris and Palaeochiropteryx are more accurately designated Microchiroptera incertae sedis. Several primitive features shown by Icaronycteris suggest that the development of a sophisticated system for echolocation within Microchiroptera occurred earlier than certain modifications of the postcranial skeleton"--P. [1].
