Microdeutopus periergos, Myers, Alan, Plaiti, Wanda & Rousou, Maria, 2018

Myers, Alan, Plaiti, Wanda & Rousou, Maria, 2018, A new species of Microdeutopus, M. periergos sp. nov. (Crustacea, Amphipoda, Senticaudata, Aoridae) from Cyprus (East Mediterranean Sea), Zootaxa 4378 (1), pp. 144-150 : 146-149

Microdeutopus periergos sp. nov.

( Figs 2–4 )

Type Material. Holotype male, 2.8 mm ( NHMUK 2017.161 ), Vasiliko Bay Cyprus 34°41’54,72” N, 33°14’30,48”E, 31 m. Paratypes, 2 males ( NHMC. 82.2.17565.01 ), Vasiliko Bay Cyprus 34°42’57,98”N, 33°19’11,92”E, 10 m ; 2 males, 3 females ( NHMC.82.2.17566.02/03), Vasiliko Bay Cyprus 34°42’36,7287”N, 33°19’26,41”E, 17 m ; 3 males ( NHMC.82.2.17567.04), Vasiliko Bay Cyprus 34°41’54,72”N, 33°14’30,48”E, 31 m.

Type locality. Vasiliko Bay , Cyprus (34°41’54,72”N, 33°14’30,48”E, 31 m.)

Etymology. Named after Greek word “ periergos ” which means curious, referring to the very elongate and slender male gnathopod 2.

Description. Based on male holotype, 2.8 mm.

Head. Head ocular lobes rounded, subocular margin moderately excavate. Antennae missing. Maxilliped flanges on anterior margins of inner and outer plates very weakly developed, weakly convex. Maxilla 1 inner plate with single long terminal seta. Maxilla 2 inner plate with oblique setal row. Mandible palp article 3 weakly falcate, 1.5 × length of article 2.

Pereon. Sternal surfaces of pereon segments lacking spines. Gnathopod 1 coxa shallow, strongly produced anteriorly, subacute; basis enlarged, swollen, broadest distally; carpus enlarged, subovoid, with single strong, broad, spine on posterodistal margin; propodus less than half length of carpus, posterior margin multilobed; dactylus strong almost as long as propodus, opposable to carpal spine. Gnathopod 2 coxa subround; basis enlarged, posterior margin strongly convex, anterior margin proximally convex distally substraight; carpus elongate, slender, three times as long as broad; propodus slender about four fifths length of carpus; dactylus short. Pereopods 3–4 dactylus elongate, more than half length of slender propodus. Pereopods 5–7 missing.

Pleon. Epimera 1–3 rounded. Uropod 1 peduncle without inter-ramal spine, rami a little longer than peduncle, inner ramus slightly longer than outer ramus. Uropod 2 peduncle without inter-ramal spine, rami much longer than peduncle, inner ramus longer than outer ramus. Uropod 3 peduncle short, inner ramus twice length of peduncle and longer than outer ramus, with a small second article. Telson without robust setae, with two slender setae on each dorsolateral crest.

Female. 2.2 mm (sexually dimorphic characters). Gnathopod 1 coxa subround; basis moderately stout, broadest distally; carpus less than twice as long as broad, subequal in length with propodus; propodus palm evenly convex and indistinct from posterior margin; dactylus strong, posterior margin with four spines. Gnathopod 2 coxa subround; basis very elongate and slender, anterior margin concave; carpus slender; propodus slender, distinctly longer than carpus, palm short, evenly convex; dactylus short, fitting palm.

Habitat. Infralittoral (6–51 m), mainly muddy sand and also sand substrate containing variable organic matter (1.933–11.119%). M. periergos sp.nov. was present in man-made installations such as harbours, fish farms, buoys or near freshwater outlets, sometimes in association with Caulerpa spp.

Remarks. Microdeutopus periergos sp. nov. superficially resembles M. armatus Chevreux in the shape of the male gnathopod 1. However, in that species, the coxa of gnathopod 1 is less produced anteriorly and the basis is swollen medially (broadest distally in M. periergos sp. nov.). It differs radically from M. armatus in the shape of the male gnathopod 2, which in M. armatus has a flange on the anterior margin of the basis (absent in M. periergos sp. nov.) short, almost rectangular carpus and propodus, (elongate in M. periergos sp. nov.) and the propodus palm with a strong distal spine (absent in M. periergos sp. nov.). In addition, in M. armatus there are strong sternal spines and the uropod 1 peduncle has a strong inter-ramal spine, both of which are missing in M. periergos sp. nov. The present species also shows similarity in the shape of the male gnathopod 1 to M. algicola Della Valle , but in that species the coxa is anteriorly strongly acute (subacute in M. periergos sp. nov.) and the posterior margin of the propodus has no lobation (lobed in M. periergos sp. nov.). It differs radically in the shape of gnathopod 2, which in M. algicola has the basis relatively slender and the carpus and propodus short and stout. M. algicola also has strong sternal spines and inter-ramal spines on the peduncle of both uropod 1 and uropod 2 both of which are missing in M. periergos sp. nov.

Distribution. The species is considered common in Vasiliko Bay (found in 27 of 42 sites), at south coast of Cyprus, Mediterranean Sea. It is known only from Cyprus.

Figures

FIGURE 2. Microdeutopus periergos sp. nov., male holotype, Vasiliko Bay, Cyprus.

FIGURE 3. Microdeutopus periergos sp. nov., male holotype, female paratype, Vasiliko Bay, Cyprus.

FIGURE 4. Microdeutopus periergos sp. nov., male holotype, Vasiliko Bay, Cyprus.