Didelphinae Gray, 1821

Voss, RS & Jansa, SA, 2009, Phylogenetic Relationships And Classification Of Didelphid Marsupials, An Extant Radiation Of New World Metatherian Mammals, Bulletin of the American Museum of Natural History 2009 (322), pp. 1-177 : 100

Subfamily Didelphinae Gray, 1821

CONTENTS: Marmosini , Metachirini , Didelphini , and Thylamyini .

DIAGNOSIS: Members of this clade uniquely differ from other didelphids by lacking an anterior cutting edge on P3 (the third upper premolar is double bladed in all basal didelphids). In addition, Didelphinae differs from Glironiinae by having a caudal dorsum that is macroscopically naked, at least near the tip; an unpaired median teat; welldeveloped posterolateral palatal corners; and postorbital processes that (when present) are formed only by the frontals. Didelphinae additionally differs from Caluromyinae by having a shorter fourth manual digit (dIII is subequal to or longer than dIV), an incompletely ossified palate (maxillopalatine and sometimes other fenestrae are invariably present), transverse canal foramina, a wide gap between the alisphenoid tympanic process and the rostral tympanic process of the petrosal, an acute and strongly inflected mandibular angle, an upper canine alveolus that lies within the premaxillary-maxillary suture, a nonvestigial P1, a larger P3 (subequal to or taller than P2), and a distinct ectoflexus on M3. Didelphinae additionally differs from Hyladelphinae by having an unpaired median teat, nonvestigial milk teeth, and a larger P3 (subequal to or taller than P2).

REMARKS: The monophyly of Didelphinae is strongly supported by all analyses of BRCA1 sequences (fig. 31), concatenated sequence data from five genes (fig. 33), and combined (nonmolecular + molecular) data when Chacodelphys is excluded (fig. 35). Subfamilial monophyly is also supported by a uniquely shared insertion (not coded for phylogenetic analysis) at the BRCA1 locus (fig. 31). However, only two morphological traits optimize as unambiguous synapomorphies of Didelphinae : an unpaired median teat and a strongly labially inflected centrocrista (subsequently reversed in Didelphini ; appendix 5). In addition to genera referred to the tribes named above, the genus † Hyperdidelphys (here unassigned to tribe) clearly belongs to this subfamily based on characters described and illustrated by Goin and Pardiñas (1996) and others subsequently scored for phylogenetic analysis by D.A. Flores and the senior author.