Tithonian ammonoids (Cephalopoda, Ammonoidea) from the Vaca Muerta Formation, Neuquén Basin, West-Central Argentina

Abstract

Ammonoids are the most abundant and diverse group of marine invertebrates present in the Vaca Muerta Formation (early Tithonian -early Valanginian) of the Neuquén Basin (west-central Argentina).A modern systematic review of the late early Tithonian -early middle Tithonian ammonoids of the Vaca Muerta Formation was conducted, focusing on perisphinctids (Superfamily Perisphinctoidea) the main components of the ammonoid assemblages.This revision was based on new fields collections and the assessing of reference type material.As a result, nine species included in four genera are identified, described and grouped into one family (Ataxioceratidae) and two subfamilies (Lithacoceratinae and Virgatosphinctinae). Subfamily Lithacoceratinae is represented by the monospecific genus Indansites (gen.nov.) and the species I. malarguensis