Shell and associated operculum in Teiichispira (Macluritidae: Gastropoda) from the Early/Middle Ordovician of the Argentine Precordillera

BERTERO VERÓNICA; FERRARI MARIEL; CARRERA MARCELO

JOURNAL OF PALEONTOLOGY

PALEONTOLOGICAL SOC INC

Lugar: Lawrence; Año: 2023 p. 549 - 557

0022-3360

Two species of TeiichispiraYochelson and Jones reported from the Early/Middle Ordovician marine deposits ofthe San Juan Formation in the Argentine Precordillera are described. The newspecies Teiichispira teresae n. sp. is  first recovered as a component of the Early/MiddleOrdovician marine gastropod assemblage in the studied region; Teiichispira argentina (Kayser),previously known from the San Juan Formation, is described with a completeteleoconch and associated operculum. The opercula of both Teiichispira species are completely preserved and present in lifeposition to the shell in T. argentina.The unguiculate morphology of the operculum is here interpreted as a mechanismfor increasing the shell weight and ensuring anchoring to the substrate in a more or less fixed mode or life for Teiichispira,and also as protection. The new occurrence of Teiichispira supplies new taxonomic data of Early Paleozoic marinegastropods in Argentina and testifies a wide paleobiogeographical distribution forthe genus, restricted to tropical and subtropical regions during the Early/MiddleOrdovician.