Epimeria (Urepimeria), 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 : 156-157

Subgenus Urepimeria subgen. nov.

urn:lsid:zoobank.org:act:95595B3C-33A1-4111-BEB0-ACD96A55BD12

Etymology

Combination of οὐρά, tail and Epimeria . The name, which is feminine, refers to the fact that the only ornamentation of the species is located on the posterior part of the animal.

Type species

Epimeria annabellae Coleman, 1994 .

Description

Body fairly opaque with teguments moderately calcified. Rostrum small to medium-sized: 0.5 to 1.1 × as long as article 1 of peduncle of antenna 1. Eyes not conical. Pereionites 1–7 and pleonites 1–2 completely smooth; pleonite 3 posterodorsally produced into a triangular tooth or a blunt lobe directed backwards, without other ornamentation. Coxae 1–3 with tip blunt or sharp, keeled or not. Coxa 4 without groove or carina, with posteroventral border distinctly concave. Coxae 5–6 without tooth or distinct protrusion. Mid of posterior border of epimeral plates 1–3 not produced into a tooth. Posteroventral tooth of epimeral plate 3 small to strong. Dorsal process of urosomite 1 produced into a triangular tooth or a rounded lobe directed upwards. Urosomite 2 without pair of small teeth pointing upwards. Lateral borders of urosomite 3 posteriorly bluntly angular. Peduncle of antenna 1 without teeth or with dentition vestigial. Mandible with molar process triturative. Lower lip with narrow (V-shaped) hypopharyngeal gap. Palp of maxilliped with 4 articles. Gnathopods of normal size, with carpus and propodus fairly stout, with palm obliquely transverse (gnathopods subcheliform); propodus not expanded distally or slightly expanded distally; posterior border of dactylus lined by row of small oblique slender teeth. Basis of pereiopods 5–6 broad and quadrato-elliptic, without posteroproximal protrusion, without posterodistal tooth. Posterior border of basis of pereiopod 7 either completely rounded or concave on distal 0.25 and terminated into a tooth. Dactylus of pereiopods 5–7 short. Benthic.

Body length

The maximum body length recorded in Urepimeria species ranges between 11 and 29 mm.

Ecology

Benthic, 0– 459 m.

Distribution

South Orkney Islands, South Shetland Islands, Palmer Archipelago, Antarctic Peninsula, eastern Weddell Sea.

Remarks

Epimeria annabellae , E. extensa , and E. monodon together constitute the subgenus Urepimeria , based on their morphological similarity.

Key to the species of Urepimeria

1. Posterodorsal projection of pleonite 3 large and triangular .......……........……………………….2

– Posterodorsal projection of pleonite 3 weak and blunt…………………………… E. (Urepimeria) extensa subgen. nov. Andres, 1985 [Southeastern tip of Antarctic Peninsula, 230–260 m]

2. Coxa 4 with sharp ventral triangular protrusion; dorsal process of urosomite 1 sharply triangular; basis of pereiopod 7 with posterodistal lobe produced into a tooth, with distal part of posterior border concave …………………………………………………………………………………… … E. (Urepimeria) annabellae subgen. nov. Coleman, 1994 [Eastern Weddell Sea, 159–459 m]

– Coxa 4 with low ventral triangular protrusion; dorsal process of urosomite 1 bluntly rounded; basis of pereiopod 7 with posterodistal lobe broadly rounded, with posterior border convex along all its length ………………………………………………………… E. (Urepimeria) monodon subgen. nov. Stephensen, 1947 [South Orkney Islands to Palmer Archipelago, infralittoral species: 0–15 m]