Epimeria (Hoplepimeria) robusta d'Acoz & Verheye 2017, subgen. nov.

Epimeria (Hoplepimeria) robusta subgen. nov. K.H. Barnard, 1930

Figs 209–211

Epimeria robusta K.H. Barnard, 1930: 375, figs 40a, 41.

Epimeria inermis – Walker 1907: 23, pl. 8 fig. 13.

Epimeria robusta – Gurjanova 1955: 198. — J.L. Barnard 1961: 103 (key). — McCain 1971: 161. — De Broyer & Klages 1991: 164 (key, in part). — Coleman 1994: 560, in part, fig. 5C only.; 1998b: 223 (in part) — Wakabara & Serejo 1999: 643 (key). — Lörz et al. 2009: 16, figs 6–9. — Lörz & Coleman 2009: 17, unnumbered photograph.

‘Clade G robusta-robustoides complex - R03’ – Verheye et al. 2016a, supplement: 4 (online).

non Epimeria inermis Walker, 1903: 54, pl. 10 fig. 69.

non Epimeria robusta – Klages & Gutt 1990: 73, fig. 1A, 4A–D (= Epimeria (Hoplepimeria) robustoides subgen. nov. Lörz & Coleman in Lörz et al., 2009).

Material examined

RV Seatruck cruises:

SOUTHERN OCEAN: 1 ♀, cruise REVOLTA I, stn REVO-043, Collect_ID: 436, Adélie Coast, 66°38ʹ28″ S, 140°01ʹ50″ E, 85–86 m, 26 Jan. 2010, coll. M. Eléaume, L. Hemery and A. D’Hont (MNHN-IU- 2009-2571) [extraction K1; Genbank nr, COI: KU870854, 28S: KU759631].

Description

ROSTRUM. Medium-sized, nearly reaching tip of article 1 of peduncle of antenna 1, anteriorly straight, ventrally straight, narrow and subacute in lateral view; of medium width and with weakly curved converging borders in frontal view.

EYE. Very large, narrowly elliptic.

PEREION–PLEOSOME TOOTH PATTERN. Pereionites 1–7 smooth; pereionite 7 dorsally scarcely carinate; pleonite 1 with weak, straight mid-dorsal carina; pleonite 2 with weak straight mid-dorsal carina, posteriorly simply angulate but not forming a tooth; pleonite 3 dorsally weakly carinate with median extremely low (inconspicuous) rounded lobe, followed by inconspicuous concavity, terminated by a narrow but blunt-tipped tooth directed upwards.

COXAE 1–3. Not carinate, apically blunt.

COXA 4. Anterodorsal border very weakly sigmoid, anteroventral border straight, these two borders being joined by very broad, blunt but very distinct squared angle (anterior corner), which is slightly projecting forward; ventral corner forming an obtuse sharp angle (ventral projection short and fairly broad); lateral carina absent; posteroventral border straight.

COXA 5. Broad, with surface smooth, with posterior border straight, with posteroventral corner forming a very blunt tooth (shape: acute triangle) projecting backwards and not laterally (no tooth or corner visible in dorsal view).

COXA 6. With posterior border straight, with posteroventral corner forming a blunt tooth (shape: narrow acute triangle) projecting backwards and not laterally (no tooth or corner visible in dorsal view).

COXA 7. Posteriorly very weakly rounded.

EPIMERAL PLATES 1–3. Posteroventral angle: angulate in plate 1, produced into a medium-sized tooth in plates 2–3.

UROSOME TOOTH PATTERN. Urosomite 1 with well developed blunt-tipped process of which the anterior border is distinctly concave and the posterior border is nearly straight; urosomite 3 with dorsolateral borders distinctly concave and posteriorly produced into a sharp triangular tooth.

TELSON. Cleft on 0.15; tips of lobes triangular and blunt, notch very broadly V-shaped and blunt at its deepest point.

GNATHOPODS 1–2. Carpus and propodus very broad; propodus expanding distally, palm distinct.

PEREIOPODS 5–7. Merus, carpus and propodus fairly broad; dactylus small, normally curved, with unguis normally developed; basis of pereiopods 5–6 broad, with posteroproximal process present, swordlike, projecting obliquely, with posterodistal corner produced into a subacute to sharp triangular tooth projecting obliquely backwards; basis of pereiopod 7 broad; posterior border with proximal 0.4 weakly rounded, with distal 0.6 deeply concave, with posterodistal corner forming a sharp triangular tooth projecting obliquely backwards.

Colour pattern

Body and coxae either yellowish, sometimes with two pairs of small yellowish spots transversally ordered on some body segments or alternatively pale yellowish with a few tiny dark dots; pereiopods and mouthparts often tinged with pink; eyes red (Lörz et al. 2009: 111, fig. 10 B–D).

Body length

Up to 43 mm.

Distribution

Adélie Coast to western Ross Sea, 85–814 m (Lörz et al. 2009; present material).

Biology

K.H. Barnard (1930) found epicaridean isopods in the marsupium of E. robusta.

Remarks

Epimeria robusta s. str. is known from Adélie Coast and the western Ross Sea. Records from the Weddell Sea and the Scotia Region are based on its close relatives E. robustoides and E. gargantua sp. nov.

Epimeria robusta can be easily distinguished from its relatives by the dentition of its pleosome (see key of Hoplepimeria subgen. nov. species).