Veselka et al. reply

Abstract

Replying to: N. B. Simmons, K. L. Seymour, J. Habersetzer & G. F. Gunnell Nature 466, 10.1038/nature09219 (2010).

We appreciate the comments of Simmons et al.¹ and welcome the new information they have provided about the oldest fossil bat, Onychonycteris finneyi, as well as their confirmation of contact between the stylohyal and tympanic bones in Myzopoda aurita, an extant laryngeal echolocator. Two skeletal features—relatively large cochleae and contact between the stylohyal and tympanic bones—identify extant bats with the capacity for laryngeal echolocation. Although the size of the cochlea can be measured in O. finneyi, the stylohyals may or may not have contacted the tympanics. Simmons et al.¹ disagree with our interpretation² of the possible contact between the stylohyal and the tympanic bone in O. finneyi, which indicated that this Eocene bat may have had the capacity for laryngeal echolocation, and have a different interpretation of our results.

Main

We agree with Simmons et al.¹ that the known specimens of O. finneyi do not provide clear morphological evidence about contact between the stylohyal and tympanic bones and, by extension, about the applicability of this character for identifying this bats’ capacity for laryngeal echolocation. As they note, the holotype of O. finneyi does provide data about the form of the stylohyal and the size of the cochlea, leading them to conclude that the bat did not echolocate.

Simmons et al. propose that the elongated stylohyal in bats is an ossified combination of stylohyal, tympanohyal and the ligament/cartilage between these two elements. The predictions arising from this hypothesis can be tested by studying patterns of development and ossification in living bats.

We join Simmons et al.¹ in awaiting the discovery and description of further fossil bats that can help to resolve the question of the origin and timing of the evolution of flight and echolocation in bats.