Browsing by Author "Hitz, Ralph B., 1964-"
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ItemNew basal Interatheriidae (Typotheria, Notoungulata, Mammalia) from the Paleogene of central Chile ; American Museum novitates, no. 3520(New York, NY : American Museum of Natural History, 2006) Hitz, Ralph B., 1964-; Flynn, John J. (John Joseph), 1955-; Wyss, Andre R.Two new basal interatheriids ("notopithecines") are described from central Chile. Specimens of a new taxon, Johnbell hatcheri, derive from Abanico Formation deposits near Termas del Flaco, in the valley of the Rio Tinguiririca, forming a distinctive element of the Tinguiririca Fauna. The Tinguiririca Fauna, which forms the basis of the recently defined Tinguirirican SALMA, documents the co-occurrence of species of archaic, dentally primitive herbivores and basal members of later diverging groups of more advanced hypsodont forms, and other transitional aspects of mammal evolution near the Eocene/Oligocene boundary. A specimen recovered from the Abanico Formation in the drainage of the Rio Cachapoal (~100 km north of Termas del Flaco), SGOPV 3451 is referred to Johnbell hatcheri. This is the first time a specimen from elsewhere in the central Chilean Main Range has been assigned to a species represented in the stratotype sequence of the Tinguiririca Fauna (upper Rio Tinguiririca Valley). Ignigena minisculus, the other new basal interatheriid recognized herein, is known only from older strata of the Abanico Formation, from the Tapado Fauna within the Rio Tinguiririca Valley, estimated to be Casamayoran in age. Phylogenetic analysis shows these two new basal interatheriids to be outgroups to the Interatheriinae. Both new taxa are smaller than all other interatheriids known, except Punapithecus. Small body size may reflect geographic provincialism, as these diminutive forms are rest[r]icted to more northern latitudes compared to larger basal interatheriids, which derive from Patagonia. SGOPV 3604, from the Abanico Formation along the Rio Azufre, several kilometers north of the Rio Tinguiririca drainage, is referred to the early interatheriid Antepithecus brachystephanus, a taxon otherwise known only from Casamayoran ("late" Barrancan subage) SALMA deposits in Patagonia. A phylogenetic definition for the name Interatheriidae is proposed on the strength of the resolution achieved in the phylogenetic analysis. This analysis also shows clearly that "Notopithecinae" represents a paraphyletic assemblage. We suggest that taxa formerly termed "notopithecines" are more appropriately referred to as "basal interatheriids".