FIRST LEONTINIID (MAMMALIA, NOTUNGULATA) FROM THE LUMBRERA FORMATION (SANTA BÁRBARA SUBGROUP, SALTA GROUP-PALEOGENE) OF NORTHWESTERN ARGENTINA

Maria V Deraco, Jaime E. Powell, López Guillermo

Abstract


Coquenia bondi gen. nov. et sp. nov., the
first leontiniid of the Lumbrera Formation, is described. It was found at a new fossiliferous site called El
Simbolar, situated north of Pampa Grande, Salta province, Argentina. It is represented by the skull and jaw
with teeth. The teeth are brachyodont. The dental formula is 3/3; 1/1; 4/4; 3/3. Caniniform incisors, with
lingual and labial cingulum. This feature associated with an I2 more developed than I1 and I3 indicates that
this new taxon is a leontiniid. The crown of the upper canine is rotated, and has a lingual and labial cingulum.
Upper premolars have an anterolingual cingulum which determines a small basin situated just in front
of the protocone. Premolars increase greatly in size from the P1 to P4, being the P1 highly reduced. Upper
molars show a lingual cingulum. All the molars have a posterior fossa. The M3 is wider towards to the base
on its lingual side. Although Lumbrera Formation was considered Casamayoran in age, the taxon described
in this paper, and other unpublished notoungulate remains found in the same stratigraphic level, suggests
that the red beds overlaying the “Faja Verde II” would be substantially younger and could be interpreted
as Mustersan or even grounger in age. These layers could be correlated with those of Casa Grande
Formation in Jujuy province (Argentina).

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