Abstract

New heterostrophic gastropods are reported from the lowermost part of the Dayie Formation (Early Triassic, Leping, Jiangxi province, China). A new genus Jiangxispira (Streptacididae) is described. Jiangxispira yangouensis new genus and new species has an almost discoidal, heterostrophic protoconch that is typical of the largely Paleozoic Streptacididae, yet the teleoconch resembles that of certain Mesozoic opisthobranchs belonging to the Superfamily Cylindrobullinoidea. This character combination in Jiangxispira may indicate a phylogenetic link between the Paleozoic Streptacididae (Allogastropoda) and the Mesozoic Cylindrobullinoidea (Opisthobranchia). Small opisthobranchs form an important component of Early Triassic gastropod faunas. The opisthobranchs seemingly benefited from selective processes operating during the Permo-Triassic mass extinction and the reorganization of gastropod faunas during the subsequent recovery period.

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