Tarsipedidae Gervais and Verreaux, 1842

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 : 242-244

Tarsipedidae Gervais and Verreaux, 1842

CONTENTS: Tarsipes (fig. 49).

STEM AGE: 27.1 Mya (95% HPD: 24.9–29.6 Mya).

CROWN AGE: N/A.

UNAMBIGUOUS CRANIODENTAL AUTAPOMORPHIES: Nasals very broad posteriorly, contacting lacrimals on each side (char. 2: 1→0; ci = 0.667); one lacrimal foramen usually present (char. 10: 0→1; ci = 0.063); jugal terminates well anterior to glenoid region (char. 21: 0→1; ci = 1.000); transverse canal foramen absent (char. 51: 1→0; ci = 0.200); auditory bulla large, contacting rostral tympanic process of petrosal (char. 55: 3→2; ci = 0.300); ectotympanic forms a closed tube that completely encircles the ear canal (char. 58: 0→1; ci = 0.167); anterior limb of ectotympanic loosely attached to the petrosal or squamosal behind postglenoid process (char. 59: 2→1; ci = 0.214); tensor tympani muscle enclosed ventrally by a bridge of bone derived from petrosal (char. 70: 0→1; ci = 1.000); postglenoid process of squamosal absent (char. 75: 0→1; ci = 0.200); postglenoid vein exits skull via the postglenoid foramen above the ear region, posterior or posteromedial to the glenoid fossa (char. 77: 1→0; ci = 0.250); zygomatic epitympanic sinus absent (char. 85: 1→0; ci = 0.500); only one hypoglossal foramen present (char. 92: 0→1; ci = 0.500); mandible much reduced and splintlike, lacking coronoid and angular processes (char. 96: 0→1; ci = 1.000); masseteric fossa perforated by a large unossified vacuity (char. 99: 1→3; ci = 0.333); and postcanine teeth are featureless spicules (char. 113: 0→1; ci = 1.000).

COMMENTS: Aplin and Archer (1987: lii) aptly described Tarsipes rostratus , the only known tarsipedid, as the “paragon of autapomorphic specialisation within Diprotodontia ,” and we identify a correspondingly long list of craniodental apomorphies characterizing this taxon, many of which are unique to Tarsipes within Metatheria. There is no known fossil record of Tarsipes prior to the latest Pleistocene ( Balme et al., 1978; Archer, 1984c; Brammall and Archer, 1999; Long et al., 2002; Archer and Hand, 2006) despite the inferred antiquity of the tarsipedid lineage, which we estimate to have diverged from other petauroids during the Oligocene. However, it is possible that at least some of the specialized features of Tarsipes arose comparatively recently, such that plesiomorphic tarsipedids might exist unrecognized among the smaller fossil “possums” known from Oligo-Miocene sites in Australia. Unfortunately, the degenerate postcanine dentition of Tarsipes precludes relevant dental comparisons, and none of the currently known fossil “possum” familes are known from wellpreserved cranial material ( Woodburne and Clemens, 1986c; Archer et al., 1987; Woodburne et al., 1987a; Crosby and Archer, 2000; Crosby, 2002a; Crosby et al., 2004; Schwartz, 2006a; Archer et al., 2018).