Short one today,
more ‘show’ than ‘tell’ as one picture and a caption pretty much tell the tale.
And a cladogram
for phylogenetic context (Fig. 2).
Onychonycteris finneyi (Simmons, Seymour, Habersetze and Gunnell 2008) Eocene (~52mya), ~27 cm in length, is the most primitive known bat. It retained unguals (claws) on all five digits, a primitive trait not shared with other bats. Derived from a sister to Chriacus, Onychonycteris phylogenetically preceded Icaronycteris, Myotis and Pteropus in the LRT (subset Fig. 2).
Onychonycteris is smaller than Chriacus,
but the preserved portions of the skull and teeth are similar in proportion and morphology (Fig. 3). So… perhaps the proportions of the missing portion of the Chriacus skull are similar (fig. 1). More fossils will tell.
Veselka et al. 2010
concluded that O. finneyi may have been capable of echolocation.
By contrast, Simmons et al. 2010
argued that O. finneyi was probably not an echolocating bat.
Simmon NB, Seymour KL, Habersetzer J, Gunnell GF 2008. Primitive Early Eocene bat from Wyoming and the evolution of flight and echolocation. Nature 451 (7180): 818–21. doi:10.1038/nature06549. PMID 18270539.
Simmons NB, Seymour KL, Habersetzer J and Gunnell GF 2010. Inferring echolation in ancient bats. Nature 466: E8.
Veselka et al. (8 co-authors) 2010. A bony connection signals larygenal echolocation in bats.Nature 463: 939–942.