Epimeria (Epimeriella) atalanta, 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 : 69-70

Epimeria (Epimeriella) atalanta sp. nov.

urn:lsid:zoobank.org:act:B0214FB1-ED96-4CEF-B267-21FC4B356C39

Figs 125–130

Epimeriella cf. scabrosa ‘4 dorsal teeth’ – d’Udekem d’Acoz & Robert 2008: 53 (list).

Epimeria cf. scabrosa – Rauschert & Arntz 2015: 62, pl. 55 unnumbered photograph.

non Epimeriella scabrosa K.H. Barnard, 1930: 378 , fig. 43.

Etymology

Ἀταλάντη is a character of the Greek mythology. She was the only woman, who took part in the nautical expedition of the Argonauts (the genus Epimeria being feminine). The name alludes to the presumed good swimming capacities of the species and its possibly pelagic life style. The name is a noun in apposition.

Type material

Holotype

RV Polarstern:

SOUTHERN OCEAN: specimen initially fixated in formalin, cruise PS69, ANT-XXIII/8, stn 725-10, south of Larsen A, 64°55.89ʹ S, 60°40.06ʹ W to 64°55.92ʹ S, 60°40.31ʹ W, 189–192 m, Rauschert dredge, 22 Jan. 2007, coll. C. d’Udekem d’Acoz and H. Robert ( RBINS, INV. 122527 ).

Description

ROSTRUM. Very minute, reduced to a narrow tiny process reaching a bit more than 0.1 of article 1 of peduncle of antenna 1.

EYE. Very large, elliptic.

PEREION–PLEOSOME TOOTH PATTERN. Pereionite 7 and pleonites 1–3 carinate and posterodorsally produced into a tooth; other body segments without mid-dorsal tooth; pereionites 1–7 and pleonites 1–3 without pair of lateral teeth.

COXAE 1–3. Not carinate; coxa 1 distally broadly rounded; coxa 2–3 distally narrow but very blunt.

COXA 4. Fairly broad; anterodorsal and anteroventral border nearly straight, joined by low and blunt angular discontinuity, anterior angle not strongly projecting forward; ventral projection short, bluntly but distinctly angular; no lateral carina; posteroventral border nearly straight.

COXA 5–7. Toothless, posteriorly, ventrally and posteroventrally rounded.

EPIMERAL PLATES 1–3. Posteroventral angle produced into a tiny tooth.

UROSOME TOOTH PATTERN. Urosomite 1 with elongate carinate process, forming a broad and regularly rounded process in lateral view.

TELSON. Cleft on 0.3; tips of lobes sharp, notch broadly V-shaped.

GNATHOPODS 1–2. Carpus and propodus short and broad; propodus not narrowing distally, palm very distinct, oblique.

PEREIOPODS 5–7. Propodus and dactylus of pereiopods 5–6 very long and very slender; basis of pereiopod 5 of normal width, without posteroproximal process, with posterior border nearly straight on most of its length, posterodistally produced into a rounded lobe; basis of pereiopods 6 broad, without posteroproximal process, with posterior border rounded on proximal half and straight on distal half, posterodistally forming a rounded angle; basis of pereiopod 7 extremely broad with posterodistal corner forming a sharp squared angle, not followed more proximally by small concavity.

Colour pattern

Body and appendages (including gnathopods and mouthparts) whitish/pellucid studded with red chromatophores arranged in large pigmented zones. Eyes reddish.

Body length

15 mm.

Distribution

Western side of the Weddell Sea: Larsen A, 189–192 m; eastern shelf of the Weddell Sea, 402–405 m (see remarks).

Remarks

Epimeria atalanta sp. nov. is very similar to E. scabrosa , but differs by the presence of a posterodorsal tooth on pereionite 7 and its broader eyes (see illustrations by K.H. Barnard 1930 and Coleman 2007). Rauschert & Arntz (2015) give a photograph of a specimen that we identify as E. atalanta sp. nov. The station was given in an early draft of their book made available to us: ANT-XXI/2 stn 145 [145-1]. Its coordinates are: ANT-XXI/2 stn 145-1, 70°56.99ʹ S, 10°48.26ʹ W to 70°56.97ʹ S, 10°47.71ʹ W (eastern Weddell Sea), 402– 405 m.

Figures

Fig. 125. Epimeria (Epimeriella) atalanta sp. nov., sex undetermined, holotype, western Weddell Sea, Larsen A, ANT-XXIII/8, stn 725-10, RBINS, INV. 122527. A. Lateral habitus. B. Dorsal habitus. C. Colour in life.

Fig. 126. Epimeria (Epimeriella) atalanta sp. nov., sex undetermined, holotype, western Weddell Sea, Larsen A, ANT-XXIII/8, stn 725-10, RBINS, INV. 122527. A. Facial habitus. B. Head in facial view.

Fig. 127. Epimeria (Epimeriella) atalanta sp. nov., sex undetermined, holotype, western Weddell Sea, Larsen A, ANT-XXIII/8, stn 725-10, RBINS, INV. 122527. A. Anterior half. B. Posterior half.

Fig. 128. Epimeria (Epimeriella) atalanta sp. nov., sex undetermined, holotype, western Weddell Sea, Larsen A, ANT-XXIII/8, stn 725-10, RBINS, INV. 122527. A. Head in lateral view. B. Urosome in dorsal view. C. Telson.

Fig. 129. Epimeria (Epimeriella) atalanta sp. nov., sex undetermined, holotype, western Weddell Sea, Larsen A, ANT-XXIII/8, stn 725-10, RBINS, INV. 122527. A. Gnathopod 1. B. Gnathopod 2.

Fig. 130. Epimeria (Epimeriella) atalanta sp. nov., sex undetermined, holotype, western Weddell Sea, Larsen A, ANT-XXIII/8, stn 725-10, RBINS, INV. 122527. A. Pereiopod 4 (proximal part). B. Pereiopod 3 or 4 (tip). C. Periopod 5 (proximal part). D. Pereiopod 6 (proximal part). E. Presumably pereiopod 6 (distal part). F. Pereiopod 7 (proximal part).