New earliest Paleocene (Puercan) periptychid ‘condylarths’ from the Great Divide Basin, Wyoming, USA

Abstract

An earliest Paleocene (Puercan) locality in the China Butte Member of the Fort Union Formation in the Great Divide Basin (GDB) of Wyoming contains a diverse mammalian faunal assemblage, including a number of 'condylarth' taxa. From UCM locality 2011035, we describe three new periptychid 'condylarths' and report first occurrences of Maiorana noctiluca, Ampliconus antoni and Conacodon harbourae from the GDB. The new genus and species Miniconus jeanninae is characterized by a ridge-like metaconid and incipient paraconid on p4, and a molar parastylid. Based on its similarity to M. jeanninae and differences from other species of Oxyacodon, O. archibaldi is placed within the new genus Miniconus. A second new genus and species Beornus honeyi is characterized by its large size with inflated premolars and molars, and small molar paraconid. A new species of Conacodon, C. hettingeri, is similar to other species of Conacodon but differs in its m3 morphology. To examine the relationships of the three new GDB taxa to each other and to other Puercan 'condylarths' from the Western Interior of North America, a phylogenetic analysis was performed using 28 Puercan periptychid and arctocyonid taxa as well as the eutherian outgroup taxon Procerberus formicarum and 64 dental characters. The resulting strict consensus tree of 210 steps confirms that the three new species from the GDB fall within Periptychidae. Beornus honeyi forms a polytomy with Mithrandir gillianus and Hemithlaeus kowalevskianus. Conacodon hettingeri is recovered as the basal member of a clade that includes the other species of Conacodon. Miniconus jeanninae is the sister to M. archibaldi. Additionally, the early Puercan Mimatuta spp. and Maiorana noctiluca fall within the Arctocyonidae, supporting the phylogenetic placement of these taxa by other recent analyses. The occurrence of the three new periptychids in the GDB indicates that mammalian diversity is higher than previously suggested for the early Puercan. http://zoobank.org/urn:lsid:zoobank.org.pub:4F31F461-814D-4C4A-99A9-3D7ED5D6701C

Evolution of olfactory receptor superfamily in bats based on high throughput molecular modelling

“…The early diversification of bats may be linked to the ecological opportunity afforded by niches vacated by the extinction of non-avian dinosaurs (Madelaine & Atteberry, 2021). Although early fossils are lacking, it has been suggested that ancestral bats in the Paleogene resembled terrestrial small-bodied insectivores (Gill et al, 2014;Madelaine & Atteberry, 2021).…”

New mammalian local faunas from the first ca. 80 ka of the Paleocene in northeastern Montana and a revised model of biotic recovery from the Cretaceous–Paleogene mass extinction

“…Thus, the greater taxonomic richness and evenness of the Littleton local fauna relative to more northern and eastern local faunas such as Luck O Hutch could relate to latitudinal and/or paleoenvironmental differences as well. The high richness of archaic ungulates in the Pu1 local fauna of the Great Divide Basin in Wyoming might also reflect a closer proximity to upland environments (Atteberry & Eberle, 2021; McComas & Eberle, 2016). That said, we underscore that these faunas have wide age brackets that might give a false sense of contemporaneity.…”

Skull of a new periptychid mammal from the lower Paleocene Denver Formation of Colorado (Corral Bluffs, El Paso County)

“…Nonetheless, the generic and specific constituents of the periptychid subgroups-Periptychinae, Anisonchinae, Conacodontinae-have fluctuated substantially (e.g., Archibald et al 1983a, b), with some likely being paraphyletic (e.g., Anisonchinae; Archibald 1993Archibald , 1998Shelley 2018). Further, recent phylogenetic hypotheses propose that Mimatuta and Maiorana, two genera traditionally considered basal periptychids (Van Valen 1978;Archibald 1998), do not belong in the Periptychidae (Shelley 2018;Atteberry and Eberle 2021), raising questions about periptychid character polarity and evolutionary trends.…”

“…Note the high species richness of periptychids relative to all other eutherian families. Species richness data were compiled from Lofgren et al (2004), Silviria (2019), Atteberry and Eberle (2021), and Wilson Mantilla et al (2021). Note that the white portion between Purgatoriidae and Taeniodonta represents the putative carnivoran Ravenictis krausei, Arctocyonidae includes taxa (e.g., Carcinodon) that were previously considered oxyclaenids (see Williamson and Carr 2007), and taxa included in the Mioclaenidae and Apheliscidae have been variously referred to the Hyopsodontidae (see Zack et al 2005 andWeil 2011).…”