Terebella lapilloides Münster, 1833 from the Upper Jurassic Lower Cretaceous İnaltı carbonates, northern Turkey: its taxonomic position and paleoenvironmental-paleoecological signifcance

Abstract

The agglutinating annelid Terebella lapilloides Münster, 1833 is commonly encountered in reefal deposits from the Late Jurassic.Tis annelid is described and documented for the frst time from the Upper Jurassic Lower Cretaceous carbonates of the İnaltı Formationin the Central Pontides, Turkey. Te whole İnaltı formation, 395 m in thickness, was studied near Bürnük village and 105 samples werecollected along the section. Te investigated thin sections reveal the shallow water and the reefal/fore-reefal character of the carbonateswith coral-sponge frame-builders. Te bioconstituents are accompanied by various microencrusters and microproblematica (such asLithocodium aggregatum , Bacinella -type structures, Koskinobullina socialis, Radiomura cautica , Perturbatacrusta leini, Taumatoporellaparvovesiculifera , and encrusting sponges and bryozoans), boring bivalves, annelids (serpulids and terebellids), echinoids, rare benthicforaminifera, and abundant Crescentiella morronensis. Rare occurrences of calpionellidsparticularly in the upper levels of the section are also observed. Te morphological analysis clearly indicates that the Terebella lapilloides population belongs to the agglutinatedannelids, which are classifed under the phylum Annelida, class Polychaete, and order Terebellida. Terebella lapilloides is a typical markerof fore-reef to upper slope or toe of slope breccia facies and is generally found in low-energy settings with dysoxic conditions. Insome levels of the studied section, Terebella and Crescentiella form an in situ association; however, Terebella never cooccurs with othermicroencrusters.