AN EOCENE ARTICULATED POLYPLACOPHORA (MOLLUSCA) FROM THE LA MESETA FORMATION, ANTARCTICA AND THE STRATIGRAPHY OF THE FOSSIL-BEARING STRATA

LOPEZ CABRERA, M.I; OLIVERO, E. B

JOURNAL OF PALEONTOLOGY

PALEONTOLOGICAL SOC INC

Lugar: Kansas; Año: 2011 vol. 85 p. 970 - 976

0022-3360

An exceptionally well-preserved specimen of Leptochiton sp. attached to a brachiopod valve isdescribed from the early Eocene beds of the La Meseta Formation, Seymour Island. It records the first fossilPolyplacophora from Antarctica. The small specimen has eight imbricating valves, rounded lateral margins, ribs offine granules, and growth marks in all valves. It strongly resembles extant Antarctic and South American speciesof Leptochiton Gray. The record of articulate valves in fossil Polyplacophora is rare and requires exceptionalpreservational conditions. Leptochiton sp. is associated with well preserved bryozoans, brachiopods, asterozoanechinoids, and serpulids, among other organisms that inhabited hard substrates in normal marine conditions, andprobably lived attached to the side walls of an incised valley eroded in Cretaceous sediments. The well-preservedfossils were probably removed from their attachment site during storm events and, after a short transportation,rapidly buried within the early Eocene valley-fill deposits. The fossil-bearing beds are included in the Telm 2 orAcantilados Allomember of the La Meseta Formation