Three new species of the genus Tanidromites (Decapoda: Brachyura: Tanidromitidae) from the Late Jurassic (Oxfordian) of Poland

Systematics and convergent evolution of multiple reef-associated Jurassic and Cretaceous crabs (Decapoda, Brachyura)

“…However, T. alexandrae and T. schweitzerae do bear deeper augenrests. Furthermore, E. aequilatus fits the diagnosis of Tanidromites (Starzyk, 2016), including the tall flanks and the similarity in overall rectangular shape, unlike species of Eodromites that tend to narrow much more posteriorly. An inflated subhepatic region as in E. aequilatus can also be seen in Tanidromites insignis (Schweigert and Koppka, 2011, figure 6C) and Tanidromites scheffnerae (I-F/MP/6261/1588/11, I-F/MP/6263/1588/ 11), and a circle of hepatic pits (=antennar extensor muscle scars), initially suggested to be characteristic of Eodromites including E. aequilatus (Starzyk, 2015b), is also present in Tanidromites scheffnerae from Poland and Austria (pers.…”

“…In many brachyurans, the hepatic region does not border the mesogastric region (e.g., Glaessner, 1969, figure 220;Davie et al, 2015, figure 71-2.6). Such mesogastric groove tubercles can be found on the internal mold and on the cuticle in representatives of Tanidromites (Starzyk, 2016(Starzyk, , 2013herein), but also in specimens of Distefania Checchia-Rispoli, 1917, Eodromites Patrulius, 1959, Gabriella Collins et al, 2006, and Pithonoton von Meyer, 1842 Gastric pits have been used extensively to describe two pits on the gastric region close to the longitudinal axis of decapods (e.g., Jakobsen and Collins, 1997;Blow, 2003;Hyzný and Müller, 2010;Klompmaker et al, 2012), but cervical pits have been used instead recently (Starzyk, 2013(Starzyk, , 2016Robin et al, 2015;Hyžný et al, 2015). We here use gastric pits because not all such pits are located clearly within the cervical groove (e.g., Dakoticancridae; Nitotacarcinus Schweitzer et al, 2007; some Etyidae) or a clear cervical groove is not always present (Paranecrocarcinidae, Zanthopsidae, some Raninoida).…”

“…The systematics and phylogeny of various Mesozoic brachyuran clades have been debated and revised extensively in the last 15 years (e.g., Feldmann, 2008a, 2009d;Karasawa et al, 2011Karasawa et al, , 2014Van Bakel et al, 2012;Wolfe et al, 2019) and dozens of new species have been described (e.g., Schweitzer and Feldmann, 2009d;Schweigert and Koppka, 2011;Klompmaker, 2013a;Starzyk, 2016;Schweitzer et al, 2018Nyborg et al, 2019). Research on trends in the biodiversity of brachyurans throughout the Mesozoic has also progressed (Klompmaker et al, 2013b;Schweitzer and Feldmann, 2015), and the positive influence of the presence of reefs for brachyuran diversity has been shown quantitatively (Klompmaker et al, 2013b).…”

“…Rather than extreme convergent evolution of the entire carapace except for some parts of orbital structure justifying placement in different superfamilies, a much simpler explanation is that Rathbunopon and Europrosopon are more closely related and best placed in the same family. Regarding differences in orbits, recent work has shown that remarkable variation can be found within genera in the expression of the margins and shape of the orbital structure (e.g., Starzyk, 2015bStarzyk, , 2016herein), implying that considerable variation may also be expected within families. Guinot (2019: p. 764) found the groove just anterior to it to represent a striking feature, but also the ovoid carapace shape, the triangular rostrum, the welldefined and elevated regions, the metagastric and urogastric regions that are parallel and linear, and the deep and wide grooves.…”

“…nov.; T. pustulosa (von Meyer, 1860), as Pithonoton; T. raboeufi Robin, Van Bakel, d'Hondt, and Charbonnier, 2015; T. richardsoni (Woodward, 1907), as Prosopon; T. scheffnerae Schweigert and Koppka, 2011 (=T. wysokaensis Starzyk, 2016); T. sculpta (Quenstedt, 1858), as Prosopon (=Prosopon lingulata von Meyer, 1858; Prosopon wuergauensis Kuhn, 1939); T. schweitzerae Starzyk, 2016;T. starzykae Schweitzer, Feldmann, Lazăr, Schweigert, and Franţescu, 2018; T. weinschenki sp.…”