New cladotherian mammal from southern Chile and the evolution of mesungulatid meridiolestidans at the dusk of the Mesozoic era

A large therian mammal from the Late Cretaceous of South America

Theria represent an extant clade that comprises placental and marsupial mammals. Here we report on the discovery of a new Late Cretaceous mammal from southern Patagonia, Patagomaia chainko gen. et sp. nov., represented by hindlimb and pelvic elements with unambiguous therian features. We estimate Patagomaia chainko attained a body mass of 14 kg, which is considerably greater than the 5 kg maximum body mass of coeval Laurasian therians. This new discovery demonstrates that Gondwanan therian mammals acquired large body size by the Late Cretaceous, preceding their Laurasian relatives, which remained small-bodied until the beginning of the Cenozoic. Patagomaia supports the view that the Southern Hemisphere was a cradle for the evolution of modern mammalian clades, alongside non-therian extinct groups such as meridiolestidans, gondwanatherians and monotremes.

Coenura Bigot as a valid genus: A molecular and morphological phylogenetic analysis of Pelecorhynchus Macquart sensu lato (Diptera: Pelecorhynchidae)

The phylogeny of the genus Pelecorhynchus Macquart (Diptera: Pelecorhynchidae) was analyzed using three genes, cytochrome oxidase I, 28S ribosomal DNA, and CAD5, with 112 morphological characteristics. A total of 59 specimens (13 outgroups and 46 ingroups) were included in the analysis. The monophyly of Pelecorhynchidae was recovered under all analyses, with Glutops Burgess as the sister group of Pelecorhynchus s.l., while Pseudoerinna jonesi (Cresson) was the sister group. Within Pelecorhynchus there are three main clades with unresolved affinities. Clade I was formed by P. personatus (Walker), P. vulpes (Macquart), P. penai Pechuman and P. kroeberi (Lindner), a well-supported clade. Clade II corresponds to the set of species of Chilean Pelecorhynchus, conformed to P. biguttatus (Philippi), P. toltensis Llanos & Gonzlez, P. elegans (Philippi), P. xanthopleura (Philippi), P. hualqui Llanos & Gonzlez, and P. longicauda (Bigot), a well-supported clade. Clade III is represented exclusively by P. fulvus Ricardo, which has an exclusively Australian distribution. The monophyly of P. fulvus and its nomenclature remain an open question, as only a single species of this taxon was included. Our study demonstrated that the concept of Pelecorhynchus should be revisited. Therefore, we restore Coenura Bigot, 1857 to generic status for part of the southern South American species of Pelecorhynchus conformed by the species C. biguttata, C. elegans, C. hualqui, C. longicauda, C. toltensis, and C. xanthopleura which are monophyletic, supported by molecular and morphological data, and consistent with a Chilean distribution.

First monotreme from the Late Cretaceous of South America

Monotremata is a clade of egg-lying mammals, represented by the living platypus and echidnas, which is endemic to Australia, and adjacent islands. Occurrence of basal monotremes in the Early Cretaceous of Australia has led to the consensus that this clade originated on that continent, arriving later to South America. Here we report on the discovery of a Late Cretaceous monotreme from southern Argentina, demonstrating that monotremes were present in circumpolar regions by the end of the Mesozoic, and that their distinctive anatomical features were probably present in these ancient forms as well.