Epimeria (Laevepimeria), 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 : 114-116

Epimeria (Laevepimeria) sp. subgen. nov.

Fig. 250

‘ Clade C walkeri complex - WA2ʹ – Verheye et al. 2016a, supplement: 3 (online).

Material examined

RV Polarstern cruise: SOUTHERN OCEAN: 1 tiny juv., cruise PS81, ANT-XXIX/3, stn 197-5, Bransfield Strait, 62°44.73ʹ S, 57°26.79ʹ W to 62°45.05ʹ S, 57°26.68ʹ W, 258–273 m, Agassiz trawl, 25 Feb. 2013 ( RBINS, INV. 122932) [extraction K40; Genbank nr, COI: KU870873 , 28S: KU759653 ].

Description

HEAD + ROSTRUM. Weakly curved in lateral view.

ROSTRUM. In lateral view short and very broad, reaching about 0.6 of article 1 of peduncle of antenna 1, anteriorly weakly convex and ventrally straight, blunt-tipped.

EYES. Huge, broadly elliptic.

PEREION–PLEOSOME TOOTH PATTERN. Pereionites 1–7 and pleonites 1–2 totally smooth; pleonite 3 missing.

COXAE 1–3. Tip broadly rounded.

COXA 4. Fairly narrow; anterodorsal border straight; anteroventral border slightly convex, these two borders being joined by very broad rounded convexity, which is distinctly projecting forward (anterior corner and anteroventral border forming a regular curve, without discontinuity); anterodorsal border 1.4 x as long as anteroventral border; ventral corner bluntly and obtusely angulate; posteroventral border nearly straight.

COXA 5. Broad, posteroventral corner very broadly rounded in lateral view.

COXA 6. Posterior border weakly convex; posteroventral corner very broadly rounded.

COXA 7. Posterior border nearly straight (inconspicuously concave); posteroventral corner broadly rounded.

EPIMERAL PLATES 1–2. Posteroventral angle very obtusely rounded in plate 1 (without any trace of tooth), produced into a small tooth in plate 2.

UROSOME. Missing.

GNATHOPODS 1–2. Carpus and propodus short and very broad; propodus not expanding distally, palm not reduced.

PEREIOPOD 6. Basis of normal width, with posteroproximal process absent, with posterodistal corner rounded or very bluntly angulate.

PEREIOPOD 7. Basis broad; posterior border strongly convex along all its length, terminated in a large rounded lobe projecting ventrally.

Body length

5 mm.

Distribution

Tip of Antarctic Peninsula: Bransfield Strait, 258– 273 m.

Remarks

A COI phylogenetic analysis ( Verheye et al. 2016a) indicates that this specimen would belong to a distinct species of the subgenus Laevepimeria subgen. nov. Since it is an incomplete and very small juvenile (about 5 mm long), it is considered inappropriate for formal description and naming. Only a photograph and a description of the morphological details visible without dissection are given herein. Within Laevepimeria subgen. nov., this specimen is more similar to E. cinderella sp. nov. regarding the shape of its coxa 4 and of the basis of its pereiopod 7. On the other hand, the tip of coxae 1–2 are broadly rounded, whilst they are subacute in E. cinderella sp. nov. However, these structures might differ in adults, as seen in other Epimeria .

Figures

Fig. 250. Epimeria (Laevepimeria) sp. subgen. nov., sex undetermined, Bransfield Strait, ANT-XXIX/3, stn 197-5, RBINS, INV. 122932, lateral habitus (urosome missing: used for DNA analysis).