Maurocarpilius n. gen ., 2020

Ossó, Àlex, Gagnaison, Cyril & Bailleul, Julien, 2020, First report of Early Eocene Decapods in Morocco: description of a new genus and a new species of Carpiliidae (Decapoda: Brachyura) with remarks on its paleobiogeography, Geodiversitas 42 (4), pp. 47-56 : 50-51

Genus Maurocarpilius n. gen.

urn:lsid:zoobank.org:act:4A10F6F4-A9CA-4C7A-B679-E10D5266A77C

TYPE SPECIES. — Maurocarpilius binodosus n. gen., n. sp. by monotypy ETYMOLOGY. — From mauri, the name given to the people who

lived in Mauritania Province, during the Roman Empire, which is the part of the current Morocco where the studied specimens were recovered. Gender: masculine.

DIAGNOSIS. — Carapace transversely ovate, wider than long, L/W ratio about 0.72, smooth. Vaulted in both senses, mainly anteriorly. Maximum width at half-length of carapace. Front slightly subtriangular, bilobed, strongly downturned. Orbits small, rounded, supraorbital margin entire, slightly rimmed. Anterolateral margin strongly convex, acute, bearing two small nodes, one at half-length level and a second at the angle with the posterolateral margin. Posterolateral margin concave, entire, acute in anterior half, starting about 60° respect to the axis. Posterior margin slightly convex. Regions not defined. Branchiocardiac grooves defined by muscle scars. Gastric pits visible. Ventral features and appendages no preserved.

REMARKS

Arose in the early Eocene carpiliids are defined by a transversely ovate and broad carapace with well demarcated margins, a usually smooth surface of carapace, anterolateral margins entire or with blunt teeth or nodes, and from poorly to not defined regions (e.g. Karasawa & Schweitzer 2006: 43; Davie et al. 2015: 1074; Schweitzer et al. 2018: 2). The inexpressiveness of the dorsal carapaces of members of Carpiliidae , often leaves comparisons between their different genera and species reduced to subtle details, as the number of anterolateral teeth, if present, to length/width or fronto-orbital ratios, shape of them, or the angle degrees of posterior margins. Feldmann et al. (2011: t. 3) in the revision of Palaeocarpilius A. Milne- Edwards, 1862, summarized the aforementioned characters of all the genera placed within Carpiliidae , which will be used in the following comparisons as well. Therefore, Maurocarpilius n. gen. is compared with all the known carpiliid genera as follow.

Braggicarpilius Beschin, Busulini & Tessier, 2015, from the Ypresian of northern Italy differs from Maurocarpilius n. gen. in having entire anterolateral margins, and convex posterolateral margins (see Beschin et al. 2015; Schweitzer et al. 2018: 3, fig. 3.1). An array of carpiliids, such as Bryocarpilius Feldmann, Schweitzer, Bennet, Frantescu, Resar & Trudeau, 2011, from the Eocene; Ocalina Rathbun, 1929 , from the Eocene; Palaeocarpilius, from the Eocene to Miocene; and Paraocalina Beschin, Busulini, De Angeli & Tessier 2007 , from Eocene, all of them with wide Tethysian and also Atlantic distribution; Proxicarpilius Collins & Morris, 1978, from the Eocene of Pakistan; and Tethyscarpilius De Angeli & Alberti, 2016, all those genera clearly differ from Maurocarpilius n. gen., in having the anterolateral margins armed from four, to up to nine nodes or teeth, instead of only two small nodes in the new genus and different ratios (see Feldmann et al. 2011: t. 3), and furthermore, in the case of Ocalina, in having a tuberculated dorsal surface (see Feldmann et al. 2011; 345-346, fig. 13; Rathbun 1929; A. Milne-Edwards 1862: 51-53; Beschin & De Angeli 2006: 11-23, figs 2-5, pls 1-4; Beschin et al. 2007: 42-43, pl. 6, figs 1b, b; Collins & Morris 1978: 972; Schweitzer et al. 2004: 100-102, fig. 6; Schweitzer et al. 2018; De Angeli & Alberti 2016). Carpilius Desmarest, 1823 , from the early Eocene to recent, differs from Maurocarpilius n. gen. in having only one anterolateral tooth instead of two, and a short but well-developed oblique carina that extends from that tooth (epibranchial) to the dorsal surface (see Desmarest 1823: 227-228; Schweitzer et al. 2018: 3, fig. 2a-b). Corallicarpilius De Angeli & Ceccon, 2015, from the early Eocene of northern Italy, differs clearly from Maurocarpilius n. gen. in having a broader and more ovate carapace, without distinction between the posterolateral and posterior margin, and in having the dorsal surface ornated with irregular tubercles, instead of smooth in the new genus (see De Angeli & Ceccon 2015: 125-126, fig. 4; Schweitzer et al. 2018: 5, fig. 3, 3a-b). Eocarpilius Blow & Manning, 1996 from the Eocene of eastern North America and westernmost Tethys, differs from Maurocarpilius n. gen. in having a longer ovoid carapace, anterolateral margins entire with only a small protuberance at the corner with antero- and posterolateral margin, posterolateral margins straight, and by its punctulate surface (see Blow & Manning 1996: 20-22, pl. 5, figs 2a, 2b; Feldmann et al. 1998: 11-12, figs 13-14; Schweitzer et al. 2018: 5, fig. 3, 3a-b). Holcocarcinus Withers, 1924, from the Eocene of Nigeria, differs clearly for the new genus in having the carapace with two marked transverse dorsal ridges (see Withers 1924: 94, pl. 5, figs 1-2; Schweitzer et al. 2018: 5, fig. 4.1). Laticarpilius Feldmann, Schweitzer, Bennet, Frantescu, Resar & Trudeau, 2011, from the Eocene of Egypt, differs from Maurocarpilius n. gen. in having a broader carapace, and a less downturned and completely triangular front (see Feldmann et al. 2011: 342-344, fig. 12; Schweitzer et al. 2018: 5, figs 4, 2a, 2b). Liopsalis von Meyer, 1862 from the Eocene of western Tethys and India, differs from the new genus in having a completely entire margins, and a triangular front not lobed (see von Meyer 1862: 161- 163, pl. 17, figs 9-12; Stoliczka 1871 pl. 5, figs 6, 6a-b; Vía 1969: 231-237, fig. 28, t. 23, figs 3-4; Feldmann et al. 2011: 344-345; Schweitzer et al. 2018: 5, fig. 4, 3). Lovaracarpilius Beschin, De Angeli, Checchi & Zarantonello, 2016 from the Eocene of northern Italy, differs from Maurocarpilius n. gen. in having shorter anterolateral margins, convex posterolateral margins, strongly punctulate surface and a triangular front (see Beschin et al. 2016: 55-56, fig. 47, pl. 9, fig. 4A-B; Schweitzer et al. 2018: 5, fig. 4, 4a-b). Oscacarpilius Artal & Van Bakel, 2018 from the northern of Iberian Peninsula, differs from the new genus in having a completely entire anterolateral margin, rounded lateral corners and a densely pitted surface ( Artal & Van Bakel 2018: 23-29, figs 1-2).

As mentioned above, the Moroccan specimens match perfectly with the general diagnosis of Carpiliidae . However, as can be seen in the comparisons, they do not fit completely with the characters or ratios of any of the aforementioned genera. Therefore, we propose the new genus, Maurocarpilius n. gen., to accommodate them.