Posted by: paulgarner | February 25, 2010

Could “the oldest bat” echolocate?

The oldest known fossil bat, Onychonycteris finneyi, from the Eocene Green River Formation of Wyoming, was originally described in Nature back in February 2008 (Simmons et al). At the time, studies of the shape of the stylohyal bone in the ear region suggested that this bat could not echolocate and it was thus interpreted as a possible morphological intermediate between bats and their presumed non-flying, non-echolocating ancestors. However, Veselka et al (2010) have reported new tomographic studies of the ears and throats of modern bats which suggest that fusion or articulation of the stylohyal and tympanic bones is a better predictor of the capacity for laryngeal echolocation than the shape of the stylohyal bone. Since the stylohyal and tympanic bones may well have articulated in Onychonycteris finneyi, Veselka et al conclude that the echolocating ability of this fossil bat needs to be re-evaluated. I know this report actually appeared in last week’s Nature but I thought it was interesting enough to give it a belated mention here.

This is likely to be my last post for at least a week, because I’ll soon be heading off to do some field work with Dr John Whitmore, who’s coming over from the States. Among other things, we’ll be taking a look at Permian sandstones on the English south coast and visiting Hutton’s famous unconformity at Siccar Point in Berwickshire. Siccar Point is an iconic place and ever since Hutton visited it with Playfair and Hall in 1788 it has been associated with the concept of deep time. For those that are interested, Dr David Tyler of the Biblical Creation Society has written an excellent introduction to Hutton’s unconformity at Siccar Point and other localities from a creationist perspective (Tyler 2003).

References

Simmons N. B., Seymour K. L., Habersetzer J., Gunnell G. F. 2008. Primitive Early Eocene bat from Wyoming and the evolution of flight and echolocation. Nature 451:818-821.

Tyler D. J. 2003. Revisiting Hutton’s unconformities. Biblical Creation Society web site.

Veselka N., McErlain D. D., Holdsworth D. W., Eger J. L., Chhem R. K., Mason M. J., Brain K. L., Faure P. A., Fenton M. B. 2010. A bony connection signals laryngeal echolocation in bats. Nature 463:939-942.

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