Pseudepimeria Chevreux 1912
- Dataset
- Epimeria of the Southern Ocean with notes on their relatives (Crustacea, Amphipoda, Eusiroidea)
- Rank
- GENUS
Classification
- kingdom
- Animalia
- phylum
- Arthropoda
- class
- Malacostraca
- order
- Amphipoda
- family
- Epimeriidae
- genus
- Pseudepimeria
biology_ecology
Ecology Benthic, 50 – 573 m.
description
Description Body opaque, with teguments strongly calcified, very strongly ornamented and sculptured by teeth and carinae. Rostrum long. Eyes conical. Pleonites 1 – 3 and pereionites 1 – 7 with strong mid-dorsal tooth. Each pereionite is entirely lined by a strong and sharp transverse carina starting on the mid-dorsal tooth and terminating at the connection with coxa; these transverse carinae bear two pairs of small teeth: a dorsolateral one and a second one just above the connection with coxa. Pleonites 1 – 2 with one pair of well developed dorsolateral teeth and smaller teeth in various arrangement more ventrally; pleonite 3 with 3 pairs of dorsolateral teeth and smaller teeth in various arrangements more ventrally. Coxae 1 – 3 (and often coxa 4) with sharp tip. Coxae 1 – 3 sharply keeled along their axis. Coxa 4 with sharp carina starting at ventral tip of coxa and terminating at posterior tip of coxa; this carina sometimes bears a tooth or a lobe projecting laterally; carina very distant from posteroventral border of coxa at its deepest point; posteroventral border of coxa concave; anterior corner of coxa strongly bulging anteriorly and sometimes produced into a tooth. Coxa 5 with strong lateral carina which is laterally or posterolaterally produced into a tooth, which is sometimes very large. Coxa 6 with strong lateral carina which is laterally or posterolaterally produced into a tooth, which is much smaller than that of coxa 5. Posteroventral tooth of epimeral plate 3 strong to very strong. Dorsal process of urosomite 1 produced into a sharp tooth directed upwards. Urosomite 2 with pair of small teeth pointing upwards. Lateral borders of urosomite 3 posteriorly terminated into a sharp tooth or an acute angle. Peduncle of antenna 1 with teeth. Mandible with molar process triturative. Lower lip with narrow (V-shaped) hypopharyngeal gap. Palp of maxilliped with 4 articles. Gnathopods very small, achelate; gnathopod 2 distinctly more slender than gnathopod 1. Basis of pereiopods 5 – 6 broad, with strong posteroproximal protrusion (which can be acute but not sword-like and which is directed posteriorly) and posterodistal tooth projecting posteriorly. Posterior border of basis of pereiopod 7 with strong median angle followed by deep excavation, terminated into a tooth projecting posteriorly. Merus, carpus and propodus of pereiopods 3 – 7 very short and very stout; dactylus medium-sized, stout and strongly curved, partly folding on propodus (as if they were designed to clasp on the branches of bushy organisms). Benthic. Body length The maximum body length recorded in Pseudepimeria species ranges between 22 and 35 mm.
discussion
Remarks Of all the Epimeria subgenera, Pseudepimeria is probably the most distinctive. Their highly sculptured and processiform body, and their strong clasping pereiopods 4 – 7 presumably reflect a specialized habitat. Hydroid remains were found in the stomach of E. (Pseudepimeria) oxicarinata (Coleman 1990 a) and pictures of this species clinging on hydroids have been published (Coleman 2007). Coleman (1988) also observed E. grandirostris eating branches of hydroids in an aquarium on the RV Polarstern. Some species are morphologically very similar to each others, but the most similar forms appear to be allopatric. These complexes include the tetrad amoenitas / debroyeri / cf. debroyeri / pulchra and the triad callista / grandirostris / kharieis. Molecular data were not available for all taxa, hence some taxonomic decisions were taken based on morphology alone. Some observed morphological differences are possibly sizedependant, which did not facilitate taxonomic decisions (descriptions are based on adult females only). Immature specimens are assumed to be conspecific with adults of the most similar species found in the same region.
distribution
Distribution Circum-Antarctic, as far north as the South Orkney Islands.
type_taxon
Type species Pseudepimeria grandirostris Chevreux, 1912.
Name
- Homonyms
- Pseudepimeria Chevreux 1912