Work

The genus Discoceras (Tarphyceratida, Cephalopoda; Ordovician) from Estonia and glacial erratics in north-central Europe

Year: 2026

Type: article

Abstract: The cephalopod genus Discoceras Barrande, 1867 (family Trocholitidae Chapman, 1857; order Tarphyceratida Flower, 1950) is a characteristic component of the late Middle and Late Ordovician carbonates of Baltoscandia and its glacial erratics in north-central Europe. The genus consists of tens of species, most of which are, however, poorly constrained, partly due to the type material being inaccessible or lost. Consequently, a comprehensive revision of the genus is needed. Here, we describe 39 specimens from in-situ rocks in northern Estonia and Norway, and from boulders in Pleistocene glaciofluvial sediments in Germany and Poland. Six previously described species were identified: Discoceras antiquissimum (Eichwald, 1842), D. saemanni (Hyatt, 1894), D. ievense (Balashov, 1953), D. damesii (Schröder, 1891), D. bandonis Remelé, 1890 and D. danckelmanni (Remelé, 1880). Two species were left in open nomenclature: D. cf. paopense Kröger, 2025 and D. cf. gubkovense Balashov, 1953; seven species are newly described: D. aseriense sp. nov., D. brandenburgense sp. nov., D. angustum sp. nov., D. circulare. sp. nov., D. sovaki sp. nov., D. alienum sp. nov. and D. polonicum sp. nov. The single specimen and holotype of Discoceras aseriense (Aseri Regional Stage, Darriwilian, Middle Ordovician) is the stratigraphically earliest known representative of the genus from Baltica and possibly globally. Lituites trapezoidalis is herein synonymised under the type species, Discoceras antiquissimum. A neotype is proposed for the latter, stabilising the concept of the type species and the genus Discoceras. The study showed that the separation of Discoceras at the family level is not justified and the monogeneric family Discoceratidae Hyatt, 1894 is herein synonymised under the family Trocholitidae Chapman, 1857.

Source: European Journal of Taxonomy

DOI: 10.5852/ejt.2026.1036.3173

Authors: Martina Aubrechtová, Dieter Korn, Björn Kröger

Institutions: Czech Academy of Sciences, Czech Academy of Sciences, Institute of Geology, Museum für Naturkunde, University of Helsinki, Finnish Museum of Natural History

Language: English

Topic: Paleontology and Stratigraphy of Fossils

Subfield: Paleontology

Field: Earth and Planetary Sciences

Domain: Physical Sciences

Open Access status: diamond

Funders: Eesti Teadusagentuur, Akademie Věd České Republiky, Tallinna Tehnikaülikool, Tartu Ülikool

Award: G1103060955