PUCADELPHYDAE, de Muizon, 1998

Ladevèze, Sandrine, 2007, Petrosal bones of metatherian mammals from the Late Palaeocene of Itaboraí (Brazil), and a cladistic analysis of petrosal features in metatherians, Zoological Journal of the Linnean Society 150 (1), pp. 85-115 : 106

PUCADELPHYDAE

This clade is supported by three unambiguous and two ambiguous synapomorphies.

The presence of a broad shelf of bone that surrounds the fenestra cochleae and makes a separation between it and the aqueductus cochleare is autapomorphic for pucadelphids (16 0> 1, RI = 1.000).

A vascular groove adjacent to the prootic sinus sulcus (36 0> 1, RI = 0.250) was observed on the mastoid part of petrosals of Pucadelphys , Andinodelphys , Type I, Type III, and the extant marsupials Monodelphis ( Wible, 2003) and Phascogale . This groove probably received a vein from the prootic sinus. The variability of this homoplastic character has not been tested on extant marsupials, because of the rarity of isolated petrosals.

The absence of a post-temporal sulcus on the squamosal surface of the petrosal for the diploetic vessels (37 0> 1, RI = 0.750) is a convergent apomorphy with the clade formed by Australidelphia, Caenolestes , and the Petrosal Types I, III, IV , and V.