Jurassic brachyurans of the genus Bucculentum Author Krzemińska, Ewa Institute of Systematics and Evolution of Animals, Polish Academy of Sciences, Poland Author Starzyk, Natalia 0000-0003-2785-6661 Institute of Systematics and Evolution of Animals, Polish Academy of Sciences, Poland & https: // orcid. org / 0000 - 0003 - 2785 - 6661 Author Fraaije, René H. B. 0000-0002-3465-1093 Oertijdmuseum, The Netherlands. https: // orcid. org / 0000 - 0002 - 3465 - 1093 Author Schweigert, Günter 0000-0003-3798-8609 Staatliches Museum für Naturkunde Stuttgart, Germany. https: // orcid. org / 0000 - 0003 - 3798 - 8609 Author Lukeneder, Alexander 0000-0002-8384-3366 Natural History Museum of Vienna, Austria. https: // orcid. org / 0000 - 0002 - 8384 - 3366 text Zootaxa 2021 2021-09-08 5032 3 395 410 journal article 10.11646/zootaxa.5032.3.5 1175-5326 5497036 321FAB6F-EEF4-4273-A2EA-C5EDFD08611F Bucculentum plettenbergense , n. sp. Fig. 1G , 7 Diagnosis . Metabranchial region large, more than half as long as carapace, and a little wider than hepatic region; augenrest round, slightly concave, shifted more dorsally than in other species of genus, and flanked laterally by long, crescent ridge; suborbital spine undivided, curved upwards; epibranchial region very narrow. Etymology . The new species is named after its type locality. Material examined . Holotype MAB 3576, Germany : Plettenberg quarry n. Balingen ( N 48 o 21’ , E 8 o 80’), coll. RHB Fraaije, Late Oxfordian: Planula Zone ( Schweigert & Callomon 1997 ; Jantschke & Schweigert 2020 ). FIGURE 6. Bucculentum horstkuscheli n. sp. , holotype SMNS 70607, Bad Überkingen-Oberböhringen, Upper Kimmeridgian. A, dorsal view; area of augenrest is between the arrows and is aligned with outline of hepatic region. B–C, two views of suborbital spine (arrows); note its various appearance. D, lateral view (most prominent tubercle of cardiac region is marked). Bars 1 mm. Description . The carapace is 8.43 mm long. The rostrum and centro-anterior portion have been split off. Left augenrest complete, large, round, shifted to dorsal side at an angle c. 50 o to the surface of carapace and delimited laterally by a narrow, crescent-like ridge. The suborbital spine is directed upwards ( Fig. 7A, B , arrows). The epibranchial region is very narrow (less than 10% of the total lateral length of carapace), with two symmetric swellings over the cardiac region. The cardiac region has three tubercles arranged axially, the distalmost one being the largest, and also the highest point of the carapace. The metabranchial region is characteristically large, a little bit wider than the hepatic region, and more than half as long as the carapace. Remarks. Bucculentum plettenbergense , n. sp. , is distinguished because of having the largest metabranchial region amongst all bucculentids, combined with the narrowest epibranchial region. Such proportions are not met in any other congener.