Epimeria (Drakepimeria) leukhoplites, d’Acoz & Verheye, 2017

d’Acoz, Cédric d’Udekem & Verheye, Marie L., 2017, Epimeria of the Southern Ocean with notes on their relatives (Crustacea, Amphipoda, Eusiroidea), European Journal of Taxonomy 359, pp. 1-553 : 41-43

Epimeria (Drakepimeria) leukhoplites subgen. et sp. nov.

urn:lsid:zoobank.org:act:E52DDFA4-14DA-4458-9A3B-403A37E19A4B

Figs 58–65

Epimeria sp aff reoproi – d’Udekem d’Acoz & Robert 2008: 56 , fig. 2.5B

non Epimeria reoproi Lörz & Coleman, 2001: 991–1001 , figs 1–5.

Etymology

From the Greek, λευκος, white; οπλιτης, hoplite, citizen-soldier of the ancient Greece. The name, which is a noun in apposition, alludes to the armoured facies and the white or whitish colour of the species.

Type material

Holotype

RV Polarstern cruises:

SOUTHERN OCEAN: 1 ovigerous ♀, fixed in alcohol 70%, cruise PS69, ANT-XXIII/8, stn 605-5, Elephant Island , 61°20.27ʹ S, 55°30.92ʹ W to 61°20.37ʹ S, 55°28.99ʹ W, 131–152 m, Agassiz trawl, 20 Dec. 2006, coll. C. d’Udekem d’Acoz and H. Robert (RBINS, INV. 122470).

Paratypes

RV Polarstern cruises:

SOUTHERN OCEAN: 3 specs,initially fixed in formalin, cruise PS69,ANT-XXIII/8, stn 605-3, Elephant Island, 61°20.33ʹ S, 55°31.53ʹ W to 61°20.35ʹ S, 55°30.18ʹ W, 148–154 m, Agassiz trawl, 20 Dec. 2006, coll. C. d’Udekem d’Acoz and H. Robert ( RBINS, INV. 122536); 1 ovigerous ♀, fixed in alcohol 70%, cruise PS69, ANT-XXIII/8, stn 614-3, Elephant Island, 60°52.37ʹ S, 55°29.80ʹ W to 60°52.71ʹ S, 55°27.83ʹ W, 248–265 m, a lot of epifauna, Rauschert dredge and Agassiz trawl, 22 Dec. 2006, coll. C. d’Udekem d’Acoz and H. Robert ( RBINS, INV. 122473); 1 spec., fixed in alcohol 70%, cruise PS69, ANT-XXIII/8, stn 671-1, northwest of King George Island, 61°59.98ʹ S, 59°14.78ʹ W to 61°60.00ʹ S, 59°10.74ʹ W, 131–144 m, bottom trawl, 1 Jan. 2007, coll. C. d’Udekem d’Acoz and H. Robert ( RBINS, INV. 122538); 1 juv., initially fixed in formalin, cruise PS69, ANT-XXIII/8, stn 728-2, northwest of Weddell Sea, south of Dundee Island, 63°42.63ʹ S, 56°01.63ʹ W to 63°42.25ʹ S, 56°02.16ʹ W, 293– 298 m, Agassiz trawl, 24 Jan. 2007, coll. C. d’Udekem d’Acoz and H. Robert ( RBINS, INV. 122539).

Description

ROBUSTNESS. Body and pereiopods more robust than in most Drakepimeria .

ROSTRUM. Medium-sized, just reaching tip of article 1 of peduncle of antenna 1 (teeth excluded), weakly curved, sharp-tipped in lateral view.

EYE. Large, elliptic.

PEREION–PLEOSOME TOOTH PATTERN. Pereionites 4 to pleonite 3 with mid-dorsal tooth; pereionite 1 to pleonite 3 with pair of dorsolateral teeth or protrusions (those of pereionites 1–2 so low that they are nearly inconspicuous); pereionites 1–3 without any trace of mid-dorsal tooth, with pair of extremely

low, nearly inconspicuous, dorsolateral protrusions; pereionite 2 slightly but distinctly narrower than pereionite 1; pereionite 4 with very small blunt-tipped posterior mid-dorsal tooth and pair of very low blunt dorsolateral protrusions; pereionite 5–6 with medium-sized blunt-tipped broad mid-dorsal tooth and pair of small blunt dorsolateral teeth, which are anteriorly prolonged by a blunt carina; pereionite 7 with well-developed acute-tipped broad mid-dorsal tooth, which is anteriorly broadly angulate, and pair of small blunt dorsolateral teeth, which are anteriorly prolonged by a blunt carina; pleonites 1–3 with very broad and not very elevated, acute-tipped mid-dorsal tooth, which is anteriorly angulate and pair of small dorsolateral non-carinate teeth; on pleonite 1 a trace of second pair of (much smaller) dorsolateral teeth is observed between the mid-dorsal tooth and the main pair of dorsolateral teeth; pleonite 3 with large acute-tipped mid-dorsal tooth bearing an inconspicuous median concavity.

COXAE 1–3. Strongly carinate and distally sharp.

COXA 4. Anterodorsal border nearly straight (inconspicuously convex) and unusually long, anteroventral border nearly straight (inconspicuously concave) and short, joined by blunt but very distinct angular discontinuity, anterior corner not projecting forward; ventral tooth narrowly triangular, not long, apically subacute; lateral carina without tooth or angularity, not projecting laterally, carina very distant from margin of coxa at its deepest point.

COXA 5. With well developed sharp and broadly triangular, carinate, lateral tooth, of which the anterior border diverges backwards and the posterior border is nearly perpendicular to body axis.

COXA 6. With mid-sized, blunt, broadly triangular, carinate, lateral tooth, of which the anterior border diverges backwards and the posterior border is perpendicular to body axis; posteroventral corner broadly rounded.

COXA 7. With ventral border distinctly curved, with posterior border nearly straight (inconspicuously convex), their convergence forming a very blunt angular discontinuity; surface of coxa posteriorly with a blunt and very low carina oriented in the dorsoventral axis.

EPIMERAL PLATES 1–3. Posteroventral angle produced into a long and sharp tooth.

UROSOME TOOTH PATTERN. Urosomite 1 with sharp triangular process pointing upwards; urosomite 2 without pair of small posterior dorsolateral teeth pointing upwards.

TELSON. Cleft on 0.33; tips of lobes subacute.

PEDUNCLE OF ANTENNA 1. Article 1 with short lateral, medial and ventral teeth reaching the base of article 2; article 2 with large lateral and medial teeth reaching about tip of article 3 (ventral tooth excluded), with ventral tooth reduced to a tiny denticle; article 3 with small ventral tooth, distinctly shorter than article itself.

GNATHOPODS 1–2. Carpus and propodus fairly robust, propodus narrowing distally, palm indistinct.

PEREIOPODS 5–7. Merus, carpus and propodus very stout; basis of pereiopods 5–6 of normal width, with posteroproximal process rounded and distinctly protruding, with posterodistal tooth strong; basis of pereiopod 7 very broad with posterodistal tooth sharp, not followed more proximally by small concavity, directed posteriorly.

Colour pattern

Uniformly whitish, or whitish with a few extremely pale, small, brownish/yellowish spots. Appendages whitish. Eyes pale reddish.

Body length

Up to 43 mm.

Distribution

Elephant Island and tip of Antarctic Peninsula, 131– 298 m.

Remark

E. leukhoplites sp. nov. is superficially similar to E. vaderi but important differences are observed. In E. leukhoplites sp. nov., coxa 5 and 6 have large triangular carinae projecting laterally, which are very distinct in dorsal view, whilst E. vaderi has no such lateral projections; this is the most obvious difference. In E. leukhoplites sp. nov., the mid-dorsal tooth of pereionite 7 and pleonites 1–2 are anteriorly very angulate, whilst they form a regular curve in E. vaderi . In E. leukhoplites sp. nov., only the pair of dorsolateral teeth of pleonite 1 is duplicated, whilst this is also the case for pleonite 2 in E. vaderi . In E. leukhoplites sp. nov., the profile of the dorsal crest of pleonite 3 is nearly straight, with an inconspicuous trace of notch just on the middle, whilst in E. vaderi it presents a shallow but long concavity. In E. leukhoplites sp. nov., the central point of the lateral carina of coxa 4 is very distant from posterior border of coxa, whilst in E. vaderi the carina remains very close to the border of the coxa. The angle joining the anterodorsal and the anteroventral angle is also more distinct in E. leukhoplites sp. nov. than in E. vaderi . The posteroventral tooth of the epimeral plates is much stronger in E. leukhoplites sp. nov. than in E. vaderi , especially for the third one. Finally, in E. leukhoplites sp. nov., the propodus of the gnathopods narrows anteriorly and the palm is indistinct, whilst in E. vaderi the propodus is not tapering and the palm is normally developed.

E. leukhoplites sp. nov. is also similar to Epimieria (Drakepimeria) subgen. nov. sp. 1 from the Ross Sea, which will be named and described in a separate paper by Verheye, Lörz & d’Udekem d’Acoz. The most obvious differences between the two species are given in the key.

Figures

Fig. 58. Epimeria (Drakepimeria) leukhoplites subgen. et sp. nov., colour in life. A, B. Ovigerous ♀, holotype, Elephant Island, ANT-XXIII/8, stn 605-5, RBINS, INV. 122470. C, D. Ovigerous ♀, paratype, Elephant Island, ANT-XXIII/8, stn 614-3, RBINS, INV. 122473.

Fig. 59. Epimeria (Drakepimeria) leukhoplites subgen. et sp. nov., ovigerous ♀, holotype, Elephant Island, ANT-XXIII/8, stn 605-5, RBINS, INV. 122470. A. Lateral habitus. B. Dorsal habitus.

Fig. 60. Epimeria (Drakepimeria) leukhoplites subgen. et sp. nov., ♀, holotype, Elephant Island, ANT- XXIII/8, stn 605-5, RBINS, INV. 122470. A. Facial habitus. B. Head in facial view.

Fig. 61. Epimeria (Drakepimeria) leukhoplites subgen. et sp. nov., ♀, holotype, Elephant Island, ANT- XXIII/8, stn 605-5, RBINS, INV. 122470. A. Anterior half. B. Coxae 4–7 and basis of pereiopods 5–7.

Fig. 62. Epimeria (Drakepimeria) leukhoplites subgen. et sp. nov., ♀, holotype, Elephant Island, ANT- XXIII/8, stn 605-5, RBINS, INV. 122470. A. Pleosome. B. Urosome.

Fig. 63. Epimeria (Drakepimeria) leukhoplites subgen. et sp. nov. A. ♀, paratype, Elephant Island, ANT-XXIII/8, stn 614-3, RBINS, INV. 122473, rostrum and peduncle of antennae in lateral view. B. ♀ holotype, Elephant Island, ANT-XXIII/8, stn 605-5, RBINS, INV. 122470, telson.

Fig. 64. Epimeria (Drakepimeria) leukhoplites subgen. et sp. nov., ♀, paratype, Elephant Island, ANT- XXIII/8, stn 614-3, RBINS, INV. 122473. A. Gnathopod 1. B. Gnathopod 2.

Fig. 65. Epimeria (Drakepimeria) leukhoplites subgen. et sp. nov., ♀, paratype, Elephant Island, ANT- XXIII/8, stn 614-3, RBINS, INV. 122473. A. Pereiopod 4. B. Pereiopod 5. C. Pereiopod 6. D. Pereiopod 7.