Craniodental Morphology And Phylogeny Of Marsupials Author Beck, Robin M. D. School of Science, Engineering and Environment University of Salford, U. K. & School of Biological, Earth & Environmental Sciences University of New South Wales, Australia & Division of Vertebrate Zoology (Mammalogy) American Museum of Natural History Author Voss, Robert S. Division of Vertebrate Zoology (Mammalogy) American Museum of Natural History Author Jansa, Sharon A. Bell Museum and Department of Ecology, Evolution, and Behavior University of Minnesota text Bulletin of the American Museum of Natural History 2022 2022-06-28 2022 457 1 353 https://bioone.org/journals/bulletin-of-the-american-museum-of-natural-history/volume-457/issue-1/0003-0090.457.1.1/Craniodental-Morphology-and-Phylogeny-of-Marsupials/10.1206/0003-0090.457.1.1.full journal article 10.1206/0003-0090.457.1.1 0003-0090 6971356 Vombatiformes Woodburne, 1984 CONTENTS: †Diprotodontoidea, † Ilariidae , † Muramura , † Namilamadeta , Phascolarctidae , and Vombatidae . STEM AGE: 39.8 Mya (95% HPD : 35.5–45.2 Mya). CROWN AGE: 32.4 Mya (95% HPD : 29.1–36.4 Mya). UNAMBIGUOUS CRANIODENTAL SYNAPOMORPHIES : Lacrimal exposure with one or more distinct tubercles (char. 8: 0→1; ci = 0.118); paroccipital process is a large erect process usually directed ventrally (char. 93: 1→2; ci = 0.100); P1 absent (char. 114: 0→1; ci = 0.200); P2 absent (char. 116: 0→1; ci = 0.333); distinct posterolingual cusp on semi- or fully sectorial P3 present (char. 125: 0→1; ci = 0.250); second lower premolar absent (char. 154: 0→1; ci = 1.000); entostylid labial to the entoconid present and cusplike (char. 174: 0→1; ci = 0.333). COMMENTS: Beck et al. (2020 : table 1 ) defined Vombatiformes as the most inclusive clade including Vombatus ursinus and Phascolarctos cinereus but not Phalanger orientalis . The family † Thylacoleonidae has usually been considered to be a member of Vombatiformes (e.g., Archer, 1984c ; Aplin and Archer, 1987 ; Aplin, 1987 ; Marshall et al., 1990 ; Munson, 1992 ; Szalay, 1994 ; Archer and Hand, 2006 ; Gillespie, 2007 ; Black et al., 2012a , 2012b ; but see Murray et al., 1987 , for an alternative view), within which it is usually placed closer to Vombatus than to Phascolarctos —in other words, as a member of Vombatomorphia sensu Beck et al. (2020 ; see below). However, as noted above, † Thylacoleonidae was placed as the sister to all other vombatiforms (i.e., outside Vombatomorphia) in our undated total-evidence analysis (fig. 32; a relationship also found by Gillespie et al., 2016 ; Beck et al., 2020 ), and it was recovered in a trichotomy at the base of Diprotodontia together with Vombatiformes and Phalangerida in our dated total-evidence analysis ( fig. 33 ). Based on these results, we suggest that † Thylacoleonidae is best considered as Diprotodontia incertae sedis. Thus, in our dated total-evidence analysis, Vombatiformes sensu Beck et al. (2020) is restricted to †Diprotodontoidea, † Ilaria , Phascolarctidae , Vombatidae , † Muramura , and † Namilimadeta . Members of the families † Maradidae , † Palorchestidae , and † Mukupirnidae have not been included here, but have been recovered within Vombatiformes in recent phylogenetic analyses ( Black et al., 2012a ; Brewer et al., 2015 ; Gillespie et al., 2016 ; Beck et al., 2020 ). Among the unambiguous synapomorphies of this restricted Vombatiformes are loss of P1, P2, and p2 (see above); all these teeth are retained in plesiomorphic thylacoleonids ( Gillespie et al., 2016 ; Beck et al., 2020 ). The oldest known definitive vombatiforms are from the late Oligocene of Australia ( Archer et al., 1999 ; Long et al., 2002 ; Archer and Hand, 2006 ; Black et al., 2012b ). This is congruent with our estimated divergence dates, which suggest that the initial diversification of vombatiforms took place during the late Eocene or early Oligocene.