Epimeria (Drakepimeria) robertiana, 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 : 57-59

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

urn:lsid:zoobank.org:act:8433E457-9757-41B0-BC19-2A95EE5E3176

Figs 99–105

Epimeria reoproi – Coleman 2007: in part, only plate 2 fig. h, not p. 49, not fig. 6, not map 13. — Lörz & Coleman 2009: unnumbered photograph on p. 17. — Rauschert & Arntz 2015: 62, pl. 55, unnumbered photograph.

‘ Clade A similis / macrodonta complex - SP2ʹ – Verheye et al. 2016a, supplement: 2 (online).

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

Etymology

The species is dedicated to Henri Robert (Royal Belgian Institute of Natural Sciences), who collected a large part of the type material. Robertianus, -a, -um is an adjective derived from his name.

Type material

Holotype

RV Polarstern cruises:

SOUTHERN OCEAN: ♂, initially fixed in formalin, cruise PS71, ANT-XXIV/2, ANDEEP-SYSTCO, eastern Weddell Sea , given by colleagues to H. Robert on 22 Dec. 2007, presumably stn 17-10, of which

the coordinates are: 70°4.58ʹ S, 3°19.66ʹ W to 70°4.48ʹ S, 3°19.20ʹ W, 2163–2190 m, Agassiz trawl, coll. H. Robert ( RBINS, INV. 132413 ).

Paratypes

RV Polarstern cruises:

SOUTHERN OCEAN: 1 spec., cruise PS48, ANT-XV/3, EASIZ II, stn 134, eastern Weddell Sea, 74°32.2ʹ S, 27°13.8ʹ W to 74°32.5ʹ S, 27°14.5ʹ W, 2054 – 2081 m, Agassiz trawl, 9 Feb. 1998, coll. C. De Broyer ( RBINS, INV. 132991); 1 immature spec., sex undetermined, cruise PS71, ANT-XXIV/2, ANDEEP-SYSTCO, stn 17-11, eastern Weddell Sea, 70°5.13ʹ S, 3°23.50ʹ W to 70°4.66ʹ S, 3°21.37ʹ W, 1724 – 2091 m, epibenthic sledge, 22 Dec. 2007, coll. H. Robert ( RBINS, INV. 132963) [extraction K44; Genbank nr, COI: KU870842 , 28S: KU759618 ]; 2 specs, initially fixed in formalin, cruise PS71, ANT- XXIV/2, ANDEEP-SYSTCO, eastern Weddell Sea, given by colleagues to H. Robert on 22 Dec. 2007, presumably stn 17-10, of which the coordinates are: 70°4.58ʹ S, 3°19.66ʹ W to 70°4.48ʹ S, 3°19.20ʹ W, 2163 – 2190 m, Agassiz trawl, coll. H. Robert ( RBINS, INV. 132413).

Description

ROSTRUM. Long, overreaching mid of article 2 of peduncle of antenna 1, scarcely curved, sharp-tipped in lateral view.

EYE. Very large, elliptic.

PEREION–PLEOSOME TOOTH PATTERN. Pereionites 1–4 without any trace of mid-dorsal tooth and dorsolateral protrusions or teeth; pereionite 2 nearly as broad as pereionite 1; pereionite 5 with very distinct posterodorsal bump and pair of weak dorsolateral teeth; pereionite 6 with small mid-dorsal tooth (of which the anterior border is straight) and pair of weak dorsolateral teeth; pereionite 7 with low mediumsized mid-dorsal tooth (of which the anterior border is weakly curved) and pair of small dorsolateral non-carinate teeth; pleonites 1–2 with low but large and very sharp, anteriorly weakly curved mid-dorsal tooth and pair of small dorsolateral non-carinate teeth; on pleonite 1 a second pair of (much smaller) dorsolateral teeth is observed between the mid-dorsal tooth and the main pair of dorsolateral teeth; pleonite 3 with low but large acute-tipped mid-dorsal tooth bearing an inconspicuous median notch and pair of small dorsolateral non-carinate teeth (mid-dorsal teeth gradually increasing in size in a backwards direction).

COXAE 1–3. Weakly carinate and distally very sharp.

COXA 4. Not broad; anterodorsal and anteroventral border straight joined by low and blunt angular discontinuity, anterior angle not projecting forward; ventral tooth medium-sized and acute; lateral carina not sharp, without tooth or angularity, carina very distant from margin of coxa at its deepest point.

COXA 5. With long, sharp and broadly triangular, carinate, lateral tooth.

COXA 6. With mid-sized, sharp and broadly triangular, carinate, lateral tooth; posteroventral corner broadly rounded.

COXA 7. With ventral border strongly convex, with posterior border distinctly convex, their convergence forming a very rounded angular discontinuity.

EPIMERAL PLATES 1–3. Posteroventral angle: produced into a medium-sized and very sharp tooth, especially the plate 3.

UROSOME TOOTH PATTERN. Urosomite 1 with sharp tooth pointing backwards of which the anterior border is weakly convex and longer than the posterior border, and of which the posterior border is strongly curved and concave; urosomite 2 without pair of small posterior dorsolateral teeth pointing upwards.

TELSON. Cleft on 0.2; tips of lobes acute, separated by very broad V-shaped notch.

PEDUNCLE OF ANTENNA 1. Article 1 without lateral tooth, with very short medial tooth, and medium-sized ventral tooth reaching 0.4 of article 2; article 2 without lateral tooth, with very short medial tooth, and short ventral tooth reaching 0.3 of article 2; article 3 with well developed ventral tooth, about as long as article itself.

GNATHOPODS 1–2. Carpus and propodus of normal slenderness; propodus not narrowing distally, palm distinct.

PEREIOPODS 5–7. Merus, carpus and propodus slender; basis of pereiopods 5–6 narrow, with posteroproximal process rounded and very weak, not well individualized, with posterodistal tooth small but acute and obliquely directed in pereiopod 5, reduced to a squared angle in pereiopod 6; basis of pereiopod 7 broad with posterodistal tooth sharp, not followed more proximally by distinct concavity, directed obliquely.

Colour pattern

Body and appendages uniformly pink or pale purple, except for eyes and gnathopods, which are red (colour photograph published by Coleman 2007 and Rauschert & Arntz 2015, both as E. reoproi ).

Body length

Up to 31 mm.

Distribution

Eastern shelf of the Weddell Sea, 1724 – 2190 m.

Remarks

Rauschert & Arntz (2015) published a colour photograph of E. robertiana sp. nov. (as E. reoproi ), without indicating the origin of the specimen. However, that information was given in an early draft of the book made available to the authors: ANT-XV/3, stn 134. The coordinates of that station are: 74°32.2ʹ S, 27°13.8ʹ W to 74°32.5ʹ S, 27°14.5ʹ W, 2054–2081 m. The same photograph was previously published (also as E. reoproi ) by Coleman (2007) and Lörz & Coleman (2009). The inclusion of E. robertiana sp. nov. in the subgenus Drakepimeria is supported by molecular data. However, its narrow basis of pereiopod 5 and its posteriorly directed process of urosomite 1 are character states unusual for the subgenus Drakepimeria . On the other hand, these character states are frequent in non-Antarctic Epimeria species, which are predominantly deep-sea forms, just like E. robertiana sp. nov.

Figures

Fig. 99. Epimeria (Drakepimeria) robertiana subgen. et sp. nov., holotype, ♂, eastern Weddell Sea, ANT-XXIV/2, presumably stn 17-10, RBINS, INV. 132413. A. Lateral habitus. B. Dorsal habitus.

Fig. 100. Epimeria (Drakepimeria) robertiana subgen. et sp. nov., holotype, ♂, eastern Weddell Sea, ANT-XXIV/2, presumably stn 17-10, RBINS, INV. 132413. A. Facial habitus. B. Head in dorsal view.

Fig. 101. Epimeria (Drakepimeria) robertiana subgen. et sp. nov., holotype, ♂, eastern Weddell Sea, ANT-XXIV/2, presumably stn 17-10, RBINS, INV. 132413. A. Coxae 1–7. B. Urosome.

Fig. 102. Epimeria (Drakepimeria) robertiana subgen. et sp. nov., holotype, ♂, eastern Weddell Sea, ANT-XXIV/2, presumably stn 17-10, RBINS, INV. 132413. A. Head in lateral view. B. Urosome in dorsal view. C. Telson.

Fig. 103. Epimeria (Drakepimeria) robertiana subgen. et sp. nov., holotype, ♂, eastern Weddell Sea, ANT-XXIV/2, presumably stn 17-10, RBINS, INV. 132413. A. Gnathopod 1. B. Gnathopod 2.

Fig. 104. Epimeria (Drakepimeria) robertiana subgen. et sp. nov., holotype, ♂, eastern Weddell Sea, ANT-XXIV/2, presumably stn 17-10, RBINS, INV. 132413. A. Pereiopod 4. B. Pereiopod 5. C. Pereiopod 6. D. Pereiopod 7.

Fig. 105. Epimeria (Drakepimeria) robertiana subgen.et sp. nov., immature paratype (sex undetermined), eastern Weddell Sea, ANT-XXIV/2, stn 17-11, RBINS, INV. 132963. A. Lateral habitus. B. Dorsal habitus.