Caenolestidae Trouessart, 1898

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 : 203-205

Caenolestidae Trouessart, 1898

CONTENTS: Caenolestes (fig. 35), Lestoros , and Rhyncholestes .

STEM AGE: 19.0 Mya (95% HPD: 14.0–23.9 Mya).

CROWN AGE: 10.0 Mya (95% HPD: 6.6–13.2 Mya).

UNAMBIGUOUS CRANIODENTAL SYNAPOMORPHIES: None (but see Comments, below).

COMMENTS: As noted above (see Paucituberculata ), our dated total-evidence analysis ( fig. 33) recovers relationships within Paucituberculata that differ somewhat from other recent studies ( Goin et al., 2007b, 2009a; Abello, 2013; Forasiepi et al., 2013; Rincón et al., 2015; Engelman et al., 2016; Abello et al., 2020, 2021), specifically in placing the pichipilid palaeothentoid † Pichipilus closer to the extant caenolestid genera Caenolestes , Lestoros , and Rhyncholestes than the fossil caenolestid † Stilotherium . Thus, monophyly of Caenolestidae including † Stilotherium is not supported here, contra these other studies. However, Caenolestes , Lestoros , and Rhyncholestes form a clade to the exclusion of our fossil terminals in our dated total-evidence analysis, which is congruent with current published evidence. This clade is not supported by any unambiguous synapomorphies, but three traits optimize as synapomorphies under Delayed Transformation: stapes columelliform and microperforate or imperforate (char. 65: 0→1; ci = 0.143; see Gaillard et al., 2021); mastoid fenestra present dorsal and medial to the mastoid exposure of petrosal (char. 91: 0→1; ci = 0.200); and fourth lower molar (m4) trigonid structurally simplified, with only the metaconid distinct (char. 164: 0→1; ci = 0.667).

The three extant caenolestid genera are estimated here as having diverged from each other relatively recently, during the mid to late Miocene, which is somewhat younger than the estimate for this split in the a posteriori time-scaled phylogeny of Abello et al. (2020: fig. 2; ~14 Mya) and the molecular-clock estimate of Mitchell et al. (2014) for the split between Caenolestes and Rhyncholestes (point estimate: 14.3 Mya; 95% HPD: 12.2– 16.0 Mya), but similar to the molecular-clock estimates of Meredith et al. (2009a; 2011). Besides a report of subfossil remains of Caenolestes fuliginosus , there is as yet no fossil record of crownclade Caenolestidae ( Abello et al., 2021) .