Phalangerida

Beck, Robin M. D., Voss, Robert S. & Jansa, Sharon A., 2022, Craniodental Morphology And Phylogeny Of Marsupials, Bulletin of the American Museum of Natural History 2022 (457), pp. 1-353 : 234-235

Phalangerida Aplin and Archer, 1987

CONTENTS: Acrobatidae , † Balbaridae , Burramyidae , † Ekaltadeta , Hypsiprymnodontidae , Macropodidae , Petauridae , Phalangeridae , Potoroidae , Pseudocheiridae , and Tarsipedidae .

STEM AGE: 39.8 Mya (95% HPD: 35.5–45.2 Mya).

CROWN AGE: 34.2 Mya (95% HPD: 30.1–38.7 Mya).

UNAMBIGUOUS CRANIODENTAL SYNAPOMORPHIES: Auditory bulla very large, extending posteriorly across the petrosal to contact the exoccipital (char. 55: 1→3; ci = 0.300); anterior limb of ectotympanic attached firmly to postglenoid process of squamosal (char. 59: 1→2; ci = 0.214); caudal tympanic process of petrosal contacts but not fused with pars cochlearis (char. 68: 0→1; ci = 0.154); postgenoid vein emerges from the postglenoid foramen in the posteromedial corner of the glenoid fossa, medial or anteromedial to the postglenoid process (if present) (char. 77: 0→1; ci = 0.250); and facial nerve exits middle ear via a a stylomastoid foramen formed by the ectotympanic, posttympanic process of the squamosal and pars canalicularis of the petrosal (char. 79: 0→4; ci = 0.625).

COMMENTS: As proposed by Aplin and Archer (1987), the suborder Phalangerida comprises all nonvombatiform diprotodontians (see also Jackson and Groves, 2015: 102–103). All recent molecular and total-evidence phylogenies, including those presented here (figs. 27–29, 32, 33), strongly support monophyly of Phalangerida to the exclusion of living vombatiforms ( Phascolarctos , Lasiorhinus , and Vombatus ). All five features that optimize as unambiguous craniodental synapomorphies of Phalangerida in our dated total-evidence analysis are in the basicranium, but all show subsequent modifications (including reversals) among different phalangeridan subclades.

Within Phalangerida , our molecular (figs. 27–29) and total-evidence (figs. 32, 33) analyses agree with most recent molecular studies (e.g., Beck, 2008a; Meredith et al., 2008b, 2009a, 2009 c, 2011; Phillips and Pratt, 2008; Mitchell et al., 2014; May-Collado et al., 2015; Duchêne et al., 2018; Álvarez-Carretero et al., 2021) in strongly supporting three major clades: Petauroidea ( Acrobatidae , Tarsipedidae , Petauridae , and Pseudocheiridae ), Burramyoidea + Phalangeroidea, and Macropodiformes. By contrast, the branching relationships among these three clades have proven difficult to resolve. In our molecular and total-evidence analyses we consistently found Petauroidea and Macropodiformes to be sister taxa in agreement with some molecular studies ( Meredith et al., 2011; Mitchell et al., 2014; May-Collado et al., 2015) but not others ( Phillips and Pratt, 2008; Meredith et al., 2009a, 2009c). Indeed, Meredith et al. (2009a) proposed the name Australoplagiaulacoidea for the Burramyoidea + Phalangeroidea + Macropodoidea clade found in their analyses. However, Duchêne et al. (2018) found that different sets of nuclear genes support alternative resolutions of this trichotomy, a result they attributed to incomplete lineage sorting.

The oldest known phalangeridans include representatives of several already distinct modern families from the late Oligocene of Australia ( Flannery and Rich, 1986; Archer et al., 1999; Long et al., 2002; Archer et al., 2006; Archer and Hand, 2006; Black et al., 2012b; Butler et al., 2017). We estimate that Phalangerida began to diversify during the late Eocene or early Oligocene.