User:Patagomaia/sandbox

Patagomaia/sandbox; Temporal range: Late Cretaceous PreꞒ Ꞓ O S D C P T J K Pg N
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	Mammalia
Clade:	Tribosphenida
Genus:	†Brasilestes; Chimento et al., 2024
Species:	†B. stardusti
Binomial name
	†Brasilestes stardusti; Chimento et al., 2024

Patagomaia chainko is an extinct therian mammal from the Maastrichtian of Patagonia. It is the largest Mesozoic mammal yet known, with weight estimates of around ~14kg.^[1]

Description[edit]

Patagomaia chainko is known from the distal end of the left ulna, two fragments of the preacetabular wing of the left ilium, acetabular region of the left hemipelvis, fragment of the ischial blade, proximal end of the right femur; distal end of the left femur, proximal end of the left tibia, and other indeterminate bone fragments. It is estimated to weight over 14 kg, narrowly beating the previous Mesozoic mammal contender, Repenomamus giganticus.

Classification[edit]

Patagomaia chainko is tentatively described as a therian mammal. It does not match any early Cenozoic South American therian groups however (Marsupialia, Sparassodonta, Xenarthra and the various South American native ungulates).

Palaeoceology[edit]

Patagomaia chainko was found alongside the monotreme Patagorhynchus, the meridiolestida Orretherium, the gondwanathere Magallanodon and several dinosaurs.

Implications[edit]

Alongside Malagasy gondwanatheres like Adalatherium and Vintana and south american mesungulatid meridiolestidans, Patagomaia chainko provides evidence that Late Cretaceous gondwannan mammal faunas tended to achieve larger sizes than their northern counterparts.^[2]