Stenula pugilla, Krapp-Schickel, Traudl & Vader, Wim, 2015

Krapp-Schickel, Traudl & Vader, Wim, 2015, Stenothoids living with or on other animals (Crustacea, Amphipoda), Zoosystematics and Evolution 91 (2), pp. 215-246 : 218-219

Taxon classification Animalia Amphipoda Stenothoidae

Stenula pugilla sp. n. Figures 14, 15, 16, 17, 18

Stenula pugilla Vader 1983: 146, sub Stenothoe sp.

Holotype.

male 3 mm in alcohol; USNM 1241824; M/v"John N.Cobb", cruise 43, sta. 45, Project Chariot Cruise, Vessel John N Cobb R/V; Chukchi Sea: 67°31'N, 167°12'W coll. Spark. 27 fm = 49 m depth, 19/8/1959. Gear dredge. From coelenteron of Haliactis arctica T. Bowman Acc.No.234238.

Additional material.

male, female on 2 slides, both 3 mm.

Type locality.

Chukchi Sea, Arctic. From coelenteron of Haliactis arctica .

Etymology.

the epitheton should remind on the shape of the propodus Gn 2, which looks somewhat like a small fist, in Latin „pugilla“; it is used as noun in apposition.

Description.

Length 3 mm.

Head. Eyes round, normal. Mouthparts: Md with very short palp, length about half of width of incisor. Mx 1 palp with one art, Mx 2 plates in tandem - position. Antennae: subequal, A 1 and A 2 flagellum about 10-12 arts. Mxp length of inner plate about half length of ischium, outer plate about 1/3-1/2 of merus.

Peraeon. Gn 1 basis on anterior margin setose, merus with short stiff setae, carpus with long setae and pectinate spines, propodus hind margin setose, somewhat rounded to nearly straight.

Cx 2 tongue-shaped. Gn 2 male and female basis on both margins beset with setae; merus rectangular, naked, carpus triangular, with stiff setae posterodistally, propodus medially widest with setose palm, defined by thumb-shaped protrusion.

Peraeopods: Cx 3 narrow, distally rounded, posteriorly with some setae; Cx 4 distally about 3 × wider than Cx 3. P 3 dactylus clearly longer than in other peraeopods; P 3-7 merus somewhat widened and not much lengthened; P 6, 7 basis widened, with parallel margins.

Pleon. U 1 peduncle spinose,> slightly unequal rami; U 2 rami subequal; U 3 peduncle = ramus art 1 = ramus art 2.

Telson naked, triangular.

Female: subsimilar to male.

Remarks.

The note 'from the coelenteron of Haliactis ' on the label of this sample may as well just have meant that the sea anemones had contracted on collection.

Discussion.

Within the above discussed criteria of dividing Stenula species into groups, the new species belongs to the majority having Gn 1 propodus subequal to carpus (together with Stenula solsbergi , see below, here transferred to Stenula ) and to the few members having a very short stump of mandible palp. The shape of Gn 2 palm male and female defined by a thumb-like hump is unique and quite helpful in identifying this species.