A new decapod crustacean faunule from the Middle Jurassic of north‐west France

Abstract

Decapod crustacean material collected recently from the lower Callovian (Middle Jurassic) in Maine-et-Loire (north-west France) comprises two new species of prosopid and one new species of tanidromitid crabs, of the genera Nodoprosopon and Tanidromites, respectively. Also represented in this faunule is a probable paguroid anomuran, in the form of isolated chelae here assigned to the genus Orhomalus, as well as appendicular remains of unknown affinity; some of the latter might belong to prosopid crabs. These anomurans and brachyurans co-occur with a diverse benthic fauna in limestones with abundant iron ooids; their main interest lies in the fact that they add valuable data to the rather poor record of Middle Jurassic decapod crustaceans.

A new early brachyuran (Crustacea, Decapoda) from the Middle Jurassic of northwest France, epibionts and ecological considerations

“…The date of von Meyer's species has been recorded incorrectly on numerous occasions. The type species, Prosopon insigne, was not mentioned by von Meyer (1857;556), although this date appears in virtually all recent publications (Schweitzer and Feldmann, 2008;Crônier and Boursicot, 2009;Hyžný et al, 2011;Schwei gert and Koppka, 2011;Fraaije et al, 2013;Starzyk, 2013), even if Glaessner (1929;321) mentioned the right date of 1860 for Prosopon insigne. Besides, von Meyer (1858; 61) proposed the binomen Prosopon insigne but no diagnosis, description or illustrations are supplied, making it a nomen nudum (ICZN art.…”

“…This species differs from T. raboeufi n. sp. in having distinctly defined branchiocardiac, cardiac and postcervical grooves, a well-defined anterior groove, a shorter (in dorsal view) carapace proportion anterior of the cervical groove, stronger pseudorostral spines (Crônier and Boursicot, 2009;pl. 1, figs.…”

A new Middle Jurassic (Bajocian) homolodromioid crab from northwest France; the earliest record of the Tanidromitidae

“…With a delay of more than a decade, the PhD dissertation by Wehner (1988) sparked a renewed interest in Jurassic brachyurans, and a plethora of papers on the taxonomy, phylogenetics and paleoecology of these taxa has appeared in recent years (e.g., Müller et al, 2000;Schweigert, 2006;Schweitzer et al, 2007;Krobicki and Zatoń, 2008;Schweitzer and Feldmann, 2008a, 2008b, 2009a, 2009b, 2010Crônier and Boursicot, 2009;Hyžný et al, 2011;Starzyk et al, 2011Starzyk et al, , 2012. The family Tanidromitidae, erected by Schweitzer and Feldmann (2008a), currently comprises two genera, namely Gabriella Collins, Ross, Genzano andMianzan, 2006 andTanidromites Schweitzer andFeldmann, 2008a.…”

Taxonomy and palaeoecology of a decapod crustacean assemblage from the Oxfordian of Stránská skála (Southern Moravia, Czech Republic)

“…Nevertheless, isolated chelae, namely propodi (sometimes articulated with dactyli), are present at Jurassic localities where dorsal carapaces of primitive brachyurans occur, and they are not scarce (MH, personal communication to Andreas Kroh and Petr Skupien as cited in Hyžný et al 2011). Only limited attention has been paid to isolated chelae loosely associated with Upper Jurassic primitive brachyurans (von Meyer 1860, Feldmann et al 2006, Crônier & Boursicot 2009, Hyžný et al 2011. Description.…”

“…We concur with Feldmann et al (2006), but add that describing and depicting cheliped elements is a crucial step in understanding their taxonomic significance. In fact, only a few authors have depicted the isolated chelae from Jurassic localities (von Meyer 1860, Feldmann et al 2006, Crônier & Boursicot 2009, Hyžný et al 2011, although tens of publications on Jurassic brachyurans exist. In this respect, for the brachyurans of the Lower 646 Głowniak (2006) and Upper Cretaceous the knowledge of cheliped morphology is more advanced and several claw types have been successfully matched to the carapaces (Jagt et al 2010, Kočová Veselská et al 2014, Hyžný & Kroh 2015.…”