Reassessment of the ?Plohophorini? (Xenarthra, Cingulata, Glyptodontidae) from uppermost miocene (late huayquerian) of pampean region of Argentina (Southern South America)

OLIVA C. G; ZAMORANO M.

Congreso; . 2nd Palaeontological Virtual Congress; 2020

The tribe ?Plohophorini? Castellanos constitutes the most emblematic and diversified clade of glyptodontids into the Upper Neogene (late Miocene ? Pliocene) of Southern South America (Argentina, Uruguay, Brazil and Peru). On the latest Miocene (Upper Huayquerian) of Argentine Pampean Region (Buenos Aires and La Pampa provinces), this lineage is represented by the genera Plohophorops Rusconi and Coscinocercus Cabrera, revisited in this contribution through a comparative analysis with related forms from the Huayquerian of Uruguay (Pseudoplohophorus Castellanos ? Stromaphoropsis Kraglievich) and ?Araucanian? of Northwestern Argentina (Stromaphorus Castellanos ? Phlyctaenopyga Cabrera). Preliminary results evidence a close morphologic relationship between Plohophorops araucanus (Ameghino) and Coscinocercus marcalaini Cabrera, being these species (probably synonymic) indistinguishable at level of their caudal armor; both differentiating from Pseudoplohophorus spp. (with equivalent rosette pattern in carapacial osteoderms) by having an elongate-most terminal tube (around 30-70% longer), characterized by exhibiting a higher complexity on its external sculpture, owing the presence of a greater amount of peripheral tubercles (12-18), tending to conform double rows around central figures (specially in transversal sense). Additionally, was prove a strong resemblance among dorsal carapaces of Coscinocercus brachyurus Cabrera and Stromaphoropsis scavinoi Kraglievich. These taxa, probably congeneric, share similar ornamentations with Stromaphorus compressidens (Moreno & Mercerat) and Phlyctaenopyga ameghini (Ameghino), differing specifically from them by retaining a flat to softly convex (non-blistered) principal figure, as well as by possessing a lesser number of peripheral elements (10-18) encircling this structure.