The generaCalliotropisSeguenza andAmbercyclusn. gen. (Vetigastropoda, Eucyclidae) from the Early Jurassic of Argentina

Abstract

The systematic position of the fossil species referred toCalliotropisis currently under debate due to the striking resemblance between these forms with their extant counterparts in general shell morphology and ornament pattern. We propose two temporal subgenera ofCalliotropis:Calliotropis(Riselloidea) for Mesozoic species andCalliotropis(Calliotropis) for Cenozoic and Recent taxa. We also synonymize the families Eucyclidae and Calliotropidae, and redescribe the type genus of Eucylidae based on topotypic material ofE. obeliscusfrom Normandy. We argue that the generic nameAmberleyashould be restricted to its type speciesAmberleya bathonica. For the species that were traditionally included inAmberleya, we propose the new genusAmbercyclus, with its type speciesAmberleya orbignyana. The present paper also provides descriptions of threeCalliotropisspecies from the Early Jurassic marine deposits of Argentina. The occurrence ofCalliotropis(Riselloidea)keidelin. sp.,Calliotropis(Riselloidea) cf.C. (R.)keideliandCalliotropis(Riselloidea) sp. in the Jurassic of Chubut and Neuquén provinces represents a new record of the genus in Early Jurassic sediments of Argentina and South America. Moreover, two species ofAmbercyclusn. gen., such asAmbercyclus espinosusandAmbercyclus?isabelensisn. sp., are described from the same deposits.Eucyclus,Amberleya,Ambercyclus, andCalliotropisare included into Eucyclidae, which we consider to be a family of Seguenzioidea.

Late Jurassic–Early Cretaceous hydrocarbon seep boulders from Novaya Zemlya and their faunas

“…Hokkaidoconchids range from the Late Jurassic to the EoceneOligocene (Gill et al, 2005;Kaim et al, 2014). The oldest known species is Hokkaidoconcha novacula from the Late Jurassic (Oxfordian) Beauvoisin hydrocarbon seep site (Kiel et al, 2010), with ‗Cerithium elatum' from Novaya Zemlya (this study) being coeval or slightly…”

“…For example, the chemosymbiotic protobranch bivalve genus Nucinella, which occur in Late Tithonian bituminous limestones, is known from some of water faunas and had broad palaeobiogeographic ranges (e.g. Oliver and Taylor, 2012;Ferrari et al, 2014). Interestingly, the Late Berriasian-Early Valanginian sandy limestones lack the seep-restricted dimerelloid brachiopod Peregrinella, which are very common in some Late…”

“…Other Late Jurassic species include Hokkaidoconcha occidentalis from the Paskenta Tithonian seep (Kiel et al, 2008b;Kaim et al, 2014) and Hokkaidoconcha hignalli from the Tithonian Gateway Pass Limestone of Antarctica (Kaim and Kelly, 2009 Kiel, 2013;Jenkins et al, 2013;Kaim et al, 2014). By their first appearance in the Late Jurassic, hokkaidoconchids are already widely distributed and occur in geographically disparate basins; this suggests a preLate Jurassic origin and dispersal for the hokkaidoconchids (cf.…”

Una nueva localidad marina de edad jurásica temprana en la cuenca sudoccidental del Chubut, Argentina.

“…Preliminary biostratigraphic analyses carried out in the southern and west-central Chubut Province (Pagani et al, 2012;Ferrari, 2013Ferrari, , 2014a indicated a late Pliensbachian-early Toarcian age for these deposits. Moreover, Damborenea and Ferrari (2008), Ferrari (2009Ferrari ( , 2011aFerrari ( , b, 2012Ferrari ( , 2013Ferrari ( , 2014a, Ferrari et al (2014) and Pagani et al (2011Pagani et al ( , 2012 recently carried out new studies on the taxonomic composition of the faunas in the Early Jurassic of south-western and central Chubut Province, including the investigation of new fossil localities and the collection of Early Jurassic material.…”

Revisión sistemática de los gastrópodos marinos del Triásico superior de Perú Central: consideraciones sobre el recambio faunístico en límite Triásico tardío/Jurásico temprano.

“…Several Argentinean Early Jurassic marine gastropods have been described by Ferrari (2009Ferrari ( , 2011Ferrari ( , 2012Ferrari ( , 2013Ferrari ( , 2014aFerrari ( , 2014b and Ferrari et al (2014) from the Chubut Province. Up to date, 13 gastropod families from the Early Jurassic (late Pliensbachianearly Toarcian) marine deposits of the Mulanguiñeu and Osta Arena formations (Chubut Province), representing 20 genera, 2 subgenera and at least 30 species are reported.…”