TAXONOMIC REVISION OF THE GLYPTODONTIDAE (MAMMALIA,XENARTHRA) PROPALAEHOPLOPHORINAE AND A PHYLOGENETIC ANALYSIS OF THE GLYPTODONTIDAE HOPLOPHORINI

GONZALEZ-RUIZ, L.; ZURITA, A. E; SCARANO, A.; SCILLATO-YANÉ, G. J.; TEJEDOR, M.F.

Las Vegas

Congreso; Annual Meeting of the SVP; 2011

SVP

The family Glyptodontidae (late Eocene-early Holocene) represents one of the most conspicuous taxa in South America, reaching North America during the Great American Biotic Interchange. From a morphological point of view, these herbivores are characterized by having cephalic, dorsal and caudal armor. More than 65 genera have now been recognized. However, previous studies were conducted in a strict typological/morphological taxonomic context, without a precise morphological characterization. This situation led to an obvious overestimation of the actual diversity of this clade, and thus a taxonomic update is clearly necessary. Until now, the few cladistic analyses carried out have failed in having badly characterized taxa in most cases. This situation is especially true for two of the most diverse groups, the Propalaehoplophorinae and the “Hoplophorinae” Hoplophorini. The Propalaehoplophorinae (late Oligocene, Deseadan SALMA- middle Miocene, Colloncuran SALMA) are one of the most basal Glyptodontidae, while the Hoplophorini (late Miocene, Huayquerian SALMAearly Holocene, Lujanian SALMA), probably represent its sister group, and retain many primitive characters. Here we present the first taxonomic update of both groups (and infact for all South American Glyptodontidae), and a comprehensive cladistic analysis of the Hoplophorini, including the Propalaehoplophorinae as an outgroup. The result shows that the Propalaehoplophorinae are represented by three well defined genera: Propalaehoplophorus (three species), Cochlops (one species) and Eucinepeltus (one species), and two additional controversial genera (“Asterostemma” and “Metopotoxus”). In turn, the Hoplophorini includes two genera: Eosclerocalyptus (three species) and Neosclerocalyptus (four species).On the other hand, the cladistic analysis suggests that the Glyptodontidae Hoplophorini is a natural group, characterized by six unambiguous synapomorphies. This result does not agree with previous analyses suggesting that the Hoplophorini is a paraphyletic group.Propalaehoplophorinae and the “Hoplophorinae” Hoplophorini. The Propalaehoplophorinae (late Oligocene, Deseadan SALMA- middle Miocene, Colloncuran SALMA) are one of the most basal Glyptodontidae, while the Hoplophorini (late Miocene, Huayquerian SALMAearly Holocene, Lujanian SALMA), probably represent its sister group, and retain many primitive characters. Here we present the first taxonomic update of both groups (and infact for all South American Glyptodontidae), and a comprehensive cladistic analysis of the Hoplophorini, including the Propalaehoplophorinae as an outgroup. The result shows that the Propalaehoplophorinae are represented by three well defined genera: Propalaehoplophorus (three species), Cochlops (one species) and Eucinepeltus (one species), and two additional controversial genera (“Asterostemma” and “Metopotoxus”). In turn, the Hoplophorini includes two genera: Eosclerocalyptus (three species) and Neosclerocalyptus (four species).On the other hand, the cladistic analysis suggests that the Glyptodontidae Hoplophorini is a natural group, characterized by six unambiguous synapomorphies. This result does not agree with previous analyses suggesting that the Hoplophorini is a paraphyletic group.