Decapoda, Brachyura, Parthenopidae) from the Eocene of Vicenza, Italy
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EOGARTHAMBRUS GUINOTAE N. GEN. AND N. SP. (DECAPODA, BRACHYURA, PARTHENOPIDAE) FROM THE EOCENE OF VICENZA, ITALY BY ANTONIO DE ANGELI1,4), ALESSANDRO GARASSINO2,5) and RICCARDO ALBERTI3,6) 1) Piazzetta Nostro Tetto, 9, I-36100 Vicenza, Italy; Museo Civico G. Zannato, Piazza Marconi, 15, 36075 Montecchio Maggiore (Vicenza), Italy 2) Museo Civico di Storia Naturale di Milano, Corso Venezia, 55, I-20121 Milano, Italy 3) Associazione Amici del Museo Civico G. Zannato, Piazza Marconi, 15, I-36075 Montecchio Maggiore (Vicenza), Italy ABSTRACT Eogarthambrus guinotae n. gen., n. sp. (Parthenopidae MacLeay, 1838) is described from the Eocene (Ypresian and Priabonian) of Vicenza, northern Italy. The shape of the carapace shows affinities with the extant representatives of Garthambrus Ng, 1996, but differs in the shape of the front and the hepatic margin. Even if strong affinities also exist with the fossil Mesolambrus Müller & Collins, 1991, from the late Eocene (Priabonian) of Hungary, the new genus differs in having a narrower front with two median teeth, anterolateral margins that form an acute angle and have five wide, flat spiny teeth. Eogarthambrus n. gen. and Mesolambrus were widespread in the Eocene seas of Europe, having preference for coral reef environments. RÉSUMÉ Eogarthambrus guinotae n. gen., n. sp. (Parthenopidae MacLeay, 1838) est décrit de l’Éocène (Yprésien et Priabonien) de Vicenza, Italie du nord. La forme de la carapace montre des affinités avec les espèces éteintes de Garthambrus Ng, 1996, mais en diffère par la forme du front et du bord hépatique. De fortes affinités existent également avec les fossiles de Mesolambrus Müller & Collins, 1991 de l’Éocène supérieur (Priabonien) de Hongrie. Le nouveau genre en diffère par un front plus étroit avec deux dents médianes, bord antérolatéral 4) Corresponding author; e-mail: [email protected] 5) e-mail: [email protected] 6) e-mail: [email protected] © Koninklijke Brill NV, Leiden, 2010 Studies on Brachyura: 107-116 108 CRM 011 – Castro et al. (eds.), BRACHYURA: A HOMAGE TO DANIÈLE GUINOT formant un angle aigu et avec cinq dents aplaties, larges et pointues. Eogarthambrus n. gen. et Mesolambrus étaient largement répartis dans les mers d’Europe à l’Éocène, de préférence dans les environnements corallines. INTRODUCTION The present specimens come from the early Eocene (Ypresian) of the Rossi quarry of Monte di Malo and from the late Eocene (Priabonian) of San Feliciano, Orgiano (Vicenza, northern Italy). The quarry, located on the eastern side of Monti Lessini Vicentini, repre- sents one of many quarries where nummulitic limestones are extracted. Many decapod crustaceans have been discovered and described by Beschin et al. (1988, 1996, 1998, 2000, 2007b). The micropalaeontologic study of the quarry was carried by Beschin et al. (1998), Beccaro (2003) and Beccaro et al. (2001). These authors recognized three different levels containing decapod crustaceans. The first two levels, located in the lower part of the quarry, are middle Ypresian (Nummulites nitidus zone) and late Ypresian (Nummulites campesinus zone), both composed of an alternation of grey-green volcanodetritic materials, micritic limestone, and calcarenite; the third level, at the top of the quarry, and middle Lutetian in age, is composed of micrite and tufaceous micrite (Morozovella lehneri zone). The quarry is also known to have yielded small fragments of Eocene amber (Boscardin & Violati Tescari, 1996; Ragazzi, 1998; Trevisani et al., 2005). One of the present specimens was discovered in the layers located below the levels containing previously known decapods (Beschin et al., 1998). These layers, perhaps from patch reefs, are composed of stratified calcarenites, are rich of coralligenous algae and corals, associated with natural moulds of molluscs, decapod crustaceans, and macroforaminifers. One similar formation was identified from the middle Ypresian of Contrada Gecchelina of Monte di Malo (Vicenza, Italy), where 350 fossil decapods belonging to 48 species were collected (Beschin et al., 2007a). The second specimen, from the quarry of San Feliciano Hill, Orgiano (south-western Monti Berici, Vicenza), was discovered in calcarenites rich in corals of late Eocene (Priabonian) age. The holotype of Phlyctenodes dalpiazi studied and described by Fabiani (1911), and housed in the collections of the University of Padova, comes from this level. The discovery of many decapods from this calcarenitic level has resulted in the description of many galatheid,.