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Cranial reconstruction of Palorchestes azael
thesisposted on 2020-06-25, 01:01 authored by Trusler, Peter William
Members of the Family Palorchestidae, are a rare and distinctive component of the Australian Cenozoic fossil fauna. The Pleistocene Palorchestes azael, was the first palorchestid species described from fragments discovered in 1851, but only in 2000 has near complete cranial material been recovered, from which a full external and internal cranial description and an accurate reconstruction could be made. This study documents the reconstruction in detailed, measured, half-tone artworks for the species. Collection surveys for comparative material has enabled the first complete cranial reconstruction for the Mid Miocene Propalorchestes novaculacephalus and the presentation of new assembled material for P. painei, P. parvus and P. pickeringi, allowing the first descriptive review of the cranial morphology of the family Palorchestidae. The distinctive retracted nasal morphology in the Palorchestidae is revealed, noting the changes that are now known to have occurred throughout their radiation. The reconstructed skull of Palorchestes azael and its related species presented here, provides an important and unique test of the correlates for a vestibular proboscis of some kind, from outside the placental lineages. There is strong support for a well-developed prehensile lip in P. azael. There is limited support for a vestibular proboscis. Many of the osteological correlates for proboscis building as defined by Clifford (2003) are lacking. Both the form and distribution of the correlates identified, negate the superficial appearance of the tapirod-like skull of P. azael and the conformation of the retracted nasal morphology of P. azael rules out the presence of a muscular proboscis of the kind seen in Tapirus. There is limited evidence for novel narial elaboration in the Palorchestidae, but beyond that, further remarks on possible structures and functions would be speculative.