The coprolite Lumbricaria Münster in the Early Tithonian of the Neuquén Basin, Argentina: new evidence for a holothurian producer

Abstract

Lumbricaria Münster is described for the first time outside the Tethys domain from distal facies of the Tithonian Vaca Muerta Formation, Neuquén Basin, Argentina. The studied material consists of elongate, convolute, cylindrical coprolites, showing an overlapping pattern, and commonly exhibiting constrictions. Internally, coprolites show a densely packed fabric, where the particles show the distinctive morphology of saccocomid ossicles. These specimens are assigned to Lumbricaria intestinum Münster and three morphotypes are defined: (a) morphotype 1 shows a disordered convolute structure; (b) morphotype 2 is shorter and has a non-convolute arrangement; and (c) morphotype 3 has a spiral arrangement. Coprolites are preserved within microbial laminites, as well as concretions in calcareous mudstones. In this paper we discuss the possible producers of these coprolites, where evidence from the studied material would support a holothurian producer.