Epimeria (Pseudepimeria) grandirostris ( Chevreux, 1912 )

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 : 129-132

Epimeria (Pseudepimeria) grandirostris ( Chevreux, 1912)

Figs 273–282

Pseudepimeria grandirostris Chevreux, 1912: 216 .

Pseudepimeria grandirostris – Chevreux 1913: 154, figs 44–46. — De Broyer 1983: 305 (in part), pl. 100.

Epimeria grandirostris – Coleman 1990a: 151–158, pls 1–4. — De Broyer & Klages 1991: 165 (key). — Wakabara & Serejo 1999: 641 (key). — Coleman 2007: 38, in part, fig. 17a–b, not colour plate 2b (= E. kharieis sp. nov.), map 8 (rhomb), in part.

‘Clade H grandirostris-pulchra-oxicarinata complex - GR1’ – Verheye et al. 2016a, supplement: 5 (online).

Material examined

RV Polarstern cruises:

SOUTHERN OCEAN: 1 very small juv., PS69, ANT-XXIII/8, stn 614-3/4/5, 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, Agassiz trawl, 22 Dec. 2006, coll. C. d’Udekem d’Acoz and H. Robert ( RBINS, INV. 122523); 1 small spec., PS69, ANT-XXIII/8, stn 605-1, Elephant Island, 61°20.35ʹ S, 55°29.16ʹ W to 61°19.98ʹ S, 55°32.67ʹ W, 146–151 m, bottom trawl, 19 Dec. 2006, coll. C. d’Udekem d’Acoz and H. Robert ( RBINS, INV. 122530); 1 small spec., PS69, ANT-XXIII/8, stn 608-1, Elephant Island, 61°11.34ʹ S, 54°43.17ʹ W to 61°11.80ʹ S, 54°40.05ʹ W, 284–293 m, bottom trawl, 20 Dec. 2006, coll. C. d’Udekem d’Acoz and H. Robert ( RBINS, INV. 122626); 1 small spec., PS69, ANT-XXIII/8, stn 654-6, Elephant Island, 61°22.80ʹ S, 56°03.84ʹ W to 61°23.35ʹ S, 56°04.89ʹ W, 341–342 m, Agassiz trawl, 29 Dec. 2006, coll. C. d’Udekem d’Acoz and H. Robert ( RBINS, INV. 122484); 1 adult ♀, PS81, ANT-XXIX/3, stn 185-3, south east of Dundee Island, 63°51.34ʹ S, 55°41.11ʹ W to 63°51.52ʹ S, 55°41.43ʹ W, bottom not muddy with a lot of life (sponges, starfishes, ophiuroids, crinoids, Pentapora -like bryozoans), 261–296 m, Agassiz trawl, 19 Feb. 2013:, coll. C. d’Udekem d’Acoz and M. Verheye ( RBINS, INV. 122946) [extraction ANT 46; Genbank nr, COI: KU870832 , 28S: KU759605 ]; 1 badly damaged small spec., PS81, ANT-XXIX/3, stn 197-6, Bransfield Strait, 62°45.05ʹ S, 57°26.68ʹ W to 62°45.09ʹ S, 57°26.47ʹ W, 210–222 m, black gravel mixed with sand and a little bit of mud, Rauschert dredge, 25 Feb. 2013, coll. C. d’Udekem d’Acoz and M. Verheye ( RBINS, INV. 122950) [extraction ANT 47; Genbank nr, COI: KU870833 , 28S: KU759606 ]

Description

Description based on adult female of ANT-XXIX/3, stn 185-3 (RBINS, INV. 122946).

ROSTRUM. Long, overreaching tip of peduncle of antenna 1; in lateral view, proximally nearly straight, distinctly curved on second 0.3, not forming a distinct angle with head, ventrally straight, tip not abruptly curving downwards; in frontal view, fairly broad, with weakly convex borders, with acute tip.

EYE. Medium-sized, conical.

PEREION–PLEOSOME TOOTH PATTERN. Pereionite 1 with low, very broad, rounded mid-dorsal tooth, of which the anterior border is very oblique, with pair of well-developed, rounded, dorsolateral teeth and pair of small ventrolateral teeth; pereionite 2 much narrower than pereionites 1 and 3, with small broad rounded tooth pointing upwards (as high as mid-dorsal tooth of pereionite 1 and distinctly shorter than mid-dorsal tooth of pereionite 3), with pair of very small dorsolateral teeth, and pair of small ventrolateral teeth; pereionites 3–7 with fairly large, broad and rounded mid-dorsal tooth of which the anterior and posterior borders are both strongly convex, with pair of medium-sized, low and blunt dorsolateral teeth, and pair of small ventrolateral teeth; pleonites 1–2 with large and broad mid-dorsal tooth pointing upwards, of which the anterior border is strongly and regularly convex (less convex in pleonite 2) and the posterior border straight, and of which the tip is subacute, and with pair of large subacute dorsolateral teeth and 4 pairs of much smaller denticles; pleonite 3 with medium-sized, fairly broad, triangular mid-dorsal tooth pointing upwards, of which the anterior border is straight (except for proximal tiny protrusion), the tip acute and the posterior border slightly but distinctly convex, with 5 pairs of dorsolateral teeth.

COXAE 1–3. Strongly carinate and distally sharp.

COXA 4. Anterodorsal border nearly straight; anteroventral border with inconspicuous concavity, with distal part distinctly convex; anterior angle extremely broadly rounded and not projecting forward; ventral tooth well developed, very broad and subacute directed backwards; lateral carina with low, very broadly rounded lobe distinctly projecting laterally, posteriorly not followed by concavity and not followed by second smaller lobe; in lateral view, the carina is forming a regular, strongly arching curve and is not at all angulate; in lateral view posteroventral border of coxa deeply concave; the concavity is rounded, not distinctly angulate.

COXA 5. In dorsal view, with medium-sized, triangular, carinate, lateral tooth, of which the anterior border points distinctly obliquely backwards and the posterior border is nearly perpendicular to body axis; tip of carina broadly rounded.

COXA 6. Triangular carinate lateral tooth of which the anterior border points obliquely backwards and the posterior border is nearly perpendicular to body (character to be examined in dorsal view); tip of carina very blunt.

COXA 7. With ventral + posterior borders forming a regular curve, with small lateral tooth.

EPIMERAL PLATES 1–3. Plate 1 with posteroventral angle sharply angulate and with small triangular tooth, with distinct lateral carina and 2 lateral teeth; plate 2 with posteroventral angle sharply angulate and produced into a small triangular tooth, with distinct lateral carina and 2 lateral teeth; plate 3 with posteroventral angle produced into a fairly long tooth, with distinct lateral carina and 1 lateral tooth, with posterior margin distinctly convex.

UROSOME TOOTH PATTERN. Urosomite 1 with sharp narrow tooth pointing upwards, not anteriorly preceded by pair of denticles; urosomite 2 with pair of tiny posterior dorsolateral teeth pointing upwards; urosomite 3 with pair of mid-sized posterior dorsolateral teeth pointing upwards.

TELSON. Cleft on 0.25; lobes laterally very convex, blunt-tipped, notch fairly narrow.

PEDUNCLE OF ANTENNA 1. Article 1 with anterior border weakly concave, with low anterior and posterior tooth; article 2 with medium-sized lateral triangular tooth; article 3 with weak ventral tooth.

GNATHOPODS 1–2. Very small, achelate; carpus and propodus of normal slenderness in gnathopod 1 (propodus tapering), extremely narrow in gnathopod 2; dactylus of gnathopod 2 very broad and posteriorly weakly convex.

PEREIOPODS 3–4. Merus, carpus and propodus extremely broad and short; dactylus fairly large, strongly curved on both sides, clasping.

PEREIOPOD 5. Basis of normal width, with posteroproximal process triangular and sharp, with posterodistal tooth fairly strong, triangular and sharp; merus, carpus and propodus extremely broad and short; dactylus fairly large, strongly curved on both sides, clasping.

PEREIOPOD 6. Basis 6 of normal width, with posteroproximal process triangular and subacute, with posterodistal tooth strong, narrow and sharp; merus, carpus and propodus extremely broad and short; dactylus fairly large, strongly curved on both sides, clasping.

PEREIOPOD 7. Basis broad; posterior border distinctly diverging from axis of basis in proximal 0.75; at this level it forms a very blunt obtuse angle, which is followed by a distinct concavity; this concavity forms a broadly rounded curve; the posterodistal corner is produced into a long triangular tooth pointing obliquely backwards; merus, carpus and propodus extremely broad and short; dactylus fairly large, strongly curved on both sides, clasping.

Allometric variations

See photographs of immatures ( Figs 279–282 ).

Colour pattern

Orange red mottling on a whitish background.

Body length

Up to 25 mm.

Distribution

Marguerite Bay, 254 m [type locality] ( Chevreux 1912, 1913); Elephant Island, Bransfield Strait, northwestern Weddell Sea (Dundee Island); 146–342 m (present material). For an inventory of older records of Epimeria of the grandirostris complex, see De Broyer et al. (2007), as Epimeria grandirostris .

Biology

Coleman (1988) observed E. grandirostris eating branches of hydroids in an aquarium on the RV Polarstern.

Remarks

The populations of the E. grandirostris complex sampled in the eastern Weddell Sea and Adélie Coast are described herein as distinct species, respectively E. kharieis sp. nov. and E. callista sp. nov. See key of the subgenus Pseudepimeria for the main diagnostic characters of adult females.

Figures

Fig. 273. Epimeria (Pseudepimeria) grandirostris (Chevreux, 1912), ♀, northwestern Weddell Sea, ANT-XXIX/3, stn 185-3, RBINS, INV. 122946. A. Lateral habitus. B. Dorsal habitus.

Fig. 274. Epimeria (Pseudepimeria) grandirostris (Chevreux, 1912), ♀, northwestern Weddell Sea, ANT-XXIX/3, stn 185-3, RBINS, INV. 122946. A. Facial habitus. B. Head in facial view.

Fig. 275. Epimeria (Pseudepimeria) grandirostris (Chevreux, 1912), ♀, northwestern Weddell Sea, ANT-XXIX/3, stn 185-3, RBINS, INV. 122946. A. Coxae. B. Pleon.

Fig. 276. Epimeria (Pseudepimeria) grandirostris (Chevreux, 1912), ♀, northwestern Weddell Sea, ANT-XXIX/3, stn 185-3, RBINS, INV. 122946. A. Head and pereionites 1–3. B. Urosome in dorsal view.

Fig. 277. Epimeria (Pseudepimeria) grandirostris (Chevreux, 1912), ♀, northwestern Weddell Sea, ANT-XXIX/3, stn 185-3, RBINS, INV. 122946. A. Lateral habitus with colour in life. B. Gnathopod 1. C. Gnathopod 2.

Fig. 278. Epimeria (Pseudepimeria) grandirostris (Chevreux, 1912), ♀, northwestern Weddell Sea, ANT-XXIX/3, stn 185-3, RBINS, INV. 122946. A. Pereiopod 4. B. Pereiopod 5. C. Pereiopod 6. D. Pereiopod 7.

Fig. 279. Epimeria (Pseudepimeria) grandirostris (Chevreux, 1912), immature, Elephant Island, ANT- XXIII/8, stn 605-1, RBINS, INV. 122530. A. Lateral habitus. B. Dorsal habitus.

Fig. 280. Epimeria (Pseudepimeria) grandirostris (Chevreux, 1912), immature, Elephant Island, ANT- XXIII/8, stn 608-1, RBINS, INV. 122626. A. Lateral habitus. B. Dorsal habitus.

Fig. 281. Epimeria (Pseudepimeria) grandirostris (Chevreux, 1912), juvenile, Elephant Island, ANT- XXIII/8, stn 654-6, RBINS, INV. 122484. A. Colour in life. B. Lateral habitus. C. Dorsal habitus.

Fig. 282. Epimeria (Pseudepimeria) grandirostris (Chevreux, 1912), small juvenile, Elephant Island, ANT-XXIII/8, stn 614-3/4/5, RBINS, INV. 122523. A. Lateral habitus. B. Dorsal habitus.