Ontogeny and relationships of the Ordovician odontopleurid trilobite Ceratocara, with new species from Argentina and New York

CHATTERTON, B.D.E., G.D. EDGECOMBE, N.E. VACCARI AND B.G. WAISFELD,

JOURNAL OF PALEONTOLOGY

The Paleontological Society

Lugar: Lawrence, Kansas; Año: 1997 p. 108 - 125

0022-3360

A growth series is described for a new species of Ceratocara Ramskold, 1991, C. argentina, from the Upper Ordovician (Caradoc) part of the Las Aguaditas Formation, near Jachal, in San Juan Province, Argentine Precordillera. Another new species of Ceratocara, C. shawi, is described from the Middle Ordovician (lower Chazy) Crown Point Formation of New York. A phylogenetic analysis is presented for the species, other well Ordovician species of Ceratocara, and some ordovician species of Ceratocephala, with Ceratocephalina tridens Whittington, 1956, as outgroup. The analysis presented supports the monophyly of the both Ceratocara and Ceratocephala Warder, 1838, their divergence have occurred by the middle Arenig. The ontogenies of the Ceratocara species from complete from protaspid to holaspid growth stages, are some the best preservad odontopleurid ontogeny described to date. material of the Ceratocephala triacantheis Whittington and Evitt, 1954, from the Crown Point Formation of the Chazy Group of New York state, is discriminated from that of Ceratocara shawi