Epimeria (Hoplepimeria) larsi, 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 : 88-90

Epimeria (Hoplepimeria) larsi subgen. nov. Lörz, 2009

Figs 185–191

Epimeria larsi Lörz, 2009: 61 , figs 2– 6.

‘Clade E georgiana-rimicarinata-rubriequies [sic] complex - GE4’ – Verheye et al. 2016a, supplement: 4 (online).

Material examined

RV Aurora Australis cruises:

SOUTHERN OCEAN: 3 small specs, cruise CEAMARC, sample CEAMARC 2173, stn 67AEV326, Adélie Coast, 65°43ʹ07″S, 143°03ʹ37″E, 1957–2154 m, beam trawl, 5 Jan.2008 (MNHN-IU-2014-4343); 1 adult ♀, cruise CEAMARC, sample CEAMARC 2173, stn 67AEV326, Adélie Coast, 65°43ʹ07″ S, 143°03ʹ37″ E, 1957–2154 m, beam trawl, 5 Jan. 2008 ( RBINS, INV. 132718, removed from MNHN- IU-2014-4344) [extraction M16; Genbank nr, COI: KU870882 , 28S: KU759665 ]; 2 ♀♀, cruise CEAMARC, sample CEAMARC 2173, Adélie Coast, stn 67AEV326, 65°43ʹ07″ S, 143°03ʹ37″ E, beam trawl, 1957–2154 m, 5 Jan. 2008 (MNHN-IU-2014-4344).

Description

ROSTRUM. Well-developed, reaching tip of article 2 of peduncle of antenna 1, anteriorly weakly curved, posteriorly nearly straight (inconspicuously concave), narrow and subacute in lateral view; narrow and with straight converging borders in dorsal view.

EYE. Very large, distinctly reniform.

PEREION–PLEOSOME TOOTH PATTERN. Pereionites 1–3 smooth; pereionite 4 with trace of posterodorsal bump; pereionite 5 with small and low posterodorsal tooth; pereionite 6 to pleonite 2 with very low mid-dorsal carina posteriorly produced into a tooth pointing backwards and very shallow median notch; pleonite 3 with very low rounded protrusion on median 0.4 followed posteriorly by a straight line and terminated by a medium-sized broad bluntly triangular tooth pointing obliquely upwards; dorsolateral ornamentation absent.

COXAE 1–3. Not carinate, apically rounded (coxa 1) and bluntly angular (coxae 2–3).

COXA 4. Anterodorsal border straight, anteroventral border straight, these two borders being joined by blunt but distinct squared angle (anterior corner), which is distinctly projecting forward; ventral corner forming an acute (nearly squared) angle (ventral projection longer than in most Hoplepimeria ); lateral carina absent; posteroventral border weakly concave.

COXA 5. Broad, with surface smooth, with posteroventral corner forming a triangular tooth projecting laterally: in dorsal view the anterior border of the tooth points obliquely backwards (it forms a low concave curve with the more anterior part of the coxa), the tip of the tooth is blunt or subacute; the posterior border of the tooth is perpendicular with the body axis.

COXA 6. With posteroventral corner forming a blunt acute but nearly squared angle, with low projection arising from its surface (forming blunt lobe in dorsal view).

COXA 7. Posteriorly rounded.

EPIMERAL PLATES 1–3. Posteroventral angle: very obtusely rounded in plate 1, produced into a small tooth in plate 2 and into a medium-sized tooth in plate 3.

UROSOME TOOTH PATTERN. Urosomite 1 with very low dorsal process, forming a symmetrical and blunttipped obtuse triangle; urosomite 3 with dorsolateral borders nearly straight (very weakly convex) and posteriorly produced into a sharp triangular tooth.

TELSON. Cleft on 0.2; tips of lobes triangular and sharp, notch broadly V-shaped and sharp at its deepest point.

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

PEREIOPODS 5–7. Merus, carpus and propodus of medium width; dactylus medium-sized; basis of pereiopods 5 of normal width, with posteroproximal process present, acutely triangular, parallel to axis of basis, far from reaching tip of basis, with posterodistal corner produced into a bluntly quadrate lobe; basis of pereiopod 6 of normal width, with posteroproximal process present, sword-like, parallel to axis of basis, nearly reaching tip of basis, with posterodistal corner produced into a bluntly quadrate lobe; basis of pereiopod 7 broad with posterior border proximally distinctly convex, with very shallow concavity on distal 0.8; with posterodistal corner produced into a bluntly quadrate lobe.

Variations

Epimeria larsi exhibits variations (possibly related to size) in the shape of the lateral projection of coxa 5. It is very long and projecting backwards in the large holotype illustrated by Lörz (2009: 66, fig. 6). It is shorter and apparently projecting laterally in the smaller paratype illustrated by Lörz (2009: 62, fig. 2); the same disposition is observed in the material studied herein. In our specimens, coxa 1 is also less blunt and the spur of the basis of pereiopod 6 a bit longer than in the specimens illustrated by Lörz (2009). On the other hand, the colour pattern is the same.

Colour pattern

Body pale pink, with a brighter pink hue on the tip of the dorsal crests; coxae bright pink; lateral border of rostrum, antennae, pereiopods and tailfan blood red. Eyes orange.

Body length

Up to 58 mm ( Lörz 2009). The specimen illustrated herein is 55 mm long.

Distribution

Western Ross Sea, 1954–1990 m (type material); Adélie Coast, 1957–2154 m (present material).

Remarks

The coordinates of the type station (TAN0802/167) as given by Lörz et al. (2009): 71°51ʹ21″ S, 71°53ʹ24″ E are incorrect, this position being located on the Antarctic mainland far away from the Ross Sea area. The correct coordinates of this station are: 71.8557°S 174.033°E ( Vargas et al. 2015: supplement 2).

Figures

Fig. 185. Epimeria (Hoplepimeria) larsi subgen. nov. Lörz, 2009, sex undetermined (presumably ♀), Adélie Coast, CEAMARC V3 2143, station ID CEAMARC-67A, Event ID 326, 65.743922° S, 142.858913° E to 65.718697° S, 143.06026° E, 1957–2154 m, colour in life (specimen not examined). Photograph: Frédéric Busson (MNHN).

Fig. 186. Epimeria (Hoplepimeria) larsi subgen. nov. Lörz, 2009, ♀, Adélie Coast, CEAMARC 2173, RBINS, INV. 132718. A. Lateral habitus. B. Dorsal habitus.

Fig. 187. Epimeria (Hoplepimeria) larsi subgen. nov. Lörz, 2009, ♀, Adélie Coast, CEAMARC 2173, RBINS, INV. 132718. A. Facial habitus. B. Head in dorsal view.

Fig. 188. Epimeria (Hoplepimeria) larsi subgen. nov. Lörz, 2009, ♀, Adélie Coast, CEAMARC 2173, RBINS, INV. 132718. A. Anterior half. B. Posterior half.

Fig. 189. Epimeria (Hoplepimeria) larsi subgen. nov. Lörz, 2009, ♀, Adélie Coast, CEAMARC 2173, RBINS, INV. 132718. A. Head and coxae 1–3 in lateral view. B. Urosome in dorsal view. C. Telson.

Fig. 190. Epimeria (Hoplepimeria) larsi subgen. nov. Lörz, 2009, ♀, Adélie Coast, CEAMARC 2173, RBINS, INV. 132718. A. Gnathopod 1. B. Gnathopod 2.

Fig. 191. Epimeria (Hoplepimeria) larsi subgen. nov. Lörz, 2009, ♀, Adélie Coast, CEAMARC 2173, RBINS, INV. 132718. A. Pereiopod 4. B. Pereiopod 5. C. Pereiopod 6. D. Pereiopod 7.