Hippomedon hurleyi Kilgallen 2009, sp. nov.
Creators: name: Kilgallen, Niamh M.
Publisher: name: Zenodo
Year: 2009
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Malacostraca
Amphipoda
Tryphosidae
Hippomedon
Hippomedon hurleyi

description: <i>Hippomedon hurleyi</i> sp. nov. (Figures 11–13) <b>Type material.</b> Holotype, non-ovigerous female, 8 mm, NIWA 48676, Kaikoura Canyon, 42º31.62’S, 173º37.32’E, 1029 m (TAN0616 /107), collected by van Veen Grab. Paratypes: 1 female, 9 mm (with deformed palp on right maxilliped), NIWA 48584, Kaikoura canyon, New Zealand, 42º30.98’S, 173º37.6’E, 1028 m (TAN0616 /109), collected by van Veen Grab; 2 females, 6–7.5 mm, NIWA 28274, Kaikoura Canyon, 42º31.39’S, 173º37.14’E, 1014 m (TAN0616 /108), collected by van Veen Grab. <b>Etymology.</b> Named after D.E. Hurley, the New Zealand taxonomist in recognition of his great contribution to the knowledge of the New Zealand amphipod fanua. <b>Diagnosis.</b> Eyes present, imperfectly developed. Lateral cephalic lobes acute. Antenna 1 subequal to antenna 2, callynophore absent. Mandible molar columnar, strongly triturative, palp attached distally. Maxilla 1 outer plate with setal-teeth in a modified 6/5 arrangement. Gnathopod 1 subchelate; palm acute, slightly convex; dactylus fitting palm. Gnathopod 2 carpus about 1.5 × propodus length, without posterodistal lobe. Pereopod 7 basis posterodistal margin slightly excavate, not produced distally. Epimeron 1 anterodistal corner producing small up-turned spine. Uropod 2 peduncle not producing flange. <b>Description of female holotype.</b> Antenna 1 subequal to antenna 2; flagellum 17-articulate, article 1 slightly longer than article 2, callynophore absent; accessory flagellum 3-articulate. Antenna 2 less than 40% of body length; flagellum 17-articulate. Calceoli absent. Eyes imperfectly developed, barely visible in alcohol. Lateral cephalic lobes acute. Epistome and upper lip seperate. Mandible incisor smooth; lacinia mobilis present on left mandible only; molar columnar and strongly triturative; palp attached distally. Maxilla 1 outer plate with setal-teeth in a modified 6/5 arrangement; palp present. Maxilla 2 inner plate without oblique setal row. Maxilliped palp 4-articulate, article 4 well developed, with unguis; outer plate large, reaching beyond halfway of palp article 3, with strong, well-developed apical robust setae; inner plate well developed, greater than half the length of outer plate. Coxae 1–3 posterodistal corner with slight notch with inserted seta. Gnathopod 1 subchelate; coxa 1 large, about as long as coxa 2, subrectangular, with straight anterior margin; ischium moderately elongate, about 1.5 × as long as broad; carpus long, very slightly longer than propodus; propodus margins subparallel, palm acute, slightly convex and minutely denticulate, defined by robust setae at posterodistal corner; dactylus fitting palm, without accessory tooth. Gnathopod 2 minutely subchelate; carpus about 1.5 × propodus length. Pereopod 3 merus weakly expanded anterodistally and subequal in length to carpus; carpus slender, subequal in length to propodus; propodus slender, without blunt, locking robust setae at posterodistal corner. Pereopod 4 coxa with moderately-developed posterodistal lobe; merus weakly expanded anterodistally and slightly longer than carpus; carpus slender, slightly shorter than propodus; propodus slender, without blunt, locking robust setae at posterodistal corner. Coxa 5 equilobate; pereopod 5 basis slightly longer than broad, slightly crenate posteriorly; merus moderately expanded posterodistally; carpus broad, robust, slightly shorter than propodus. Pereopod 6 basis slender, distinctly longer than broad, posterior margin slightly crenate; merus barely expanded posteriorly; carpus slender, subequal in length to propodus. Pereopod 7 basis longer than broad, crenate posteriorly, slightly producing posterodistal lobe, not reaching merus; merus not expanded. Gills from gnathopod 2 to pereopod 7. Epimeron 1 anterodistal corner quadrate. Epimeron 2 posterodistal corner quadrate. Epimeron 3 posterodistal corner produced, forming a large upturned spine. Urosomite 1 with slight dorsal depression. Uropod 1 peduncle slightly longer than rami; rami subequal. Uropod 2 peduncle subequal in length to rami, not producing flange; rami subequal, inner ramus without marginal constriction. Uropod 3 peduncle distinctly shorter than rami; outer ramus much longer than inner ramus, outer ramus 2-articulate, article 2 about 33% the length of article 1, inner ramus not extending past article 1 of outer ramus. Telson distinctly longer than broad, deeply cleft. <b>Length.</b> 9 mm. <b>Distribution.</b> New Zealand: Kaikoura canyon; 1014–1029 m. <b>Ecology.</b> Associated with marine canyon sediments. <b>Remarks.</b> Unlike other hippomedontines, <i>H. hurleyi</i> <b>sp. nov.</b> appears not to possess a callynophore and is thus unusual in this regard. Otherwise, it is most similar to <i>H. tasmanicus</i> Barnard, 1961, differing in the presence of eyes; the relative length of antenna 1, which is much shorter than antenna 2 in <i>H. tasmanicus</i> but subequal to antenna 2 in this species; the shape of epimeron 3, which is more strongly produced in <i>H. hurleyi</i>; and the relative length of the inner ramus of uropod 3, which does not reach to article 2 of the outer ramus in <i>H. hurleyi</i>, but reaches beyond it in <i>H. tasmanicus,</i> article 2 of the outer ramus also being much shorter in the latter species.
description: Published as part of <i>Kilgallen, Niamh M., 2009, New species of lysianassoid Amphipoda (Crustacea) associated with seamounts, marine canyons and cold seeps of New Zealand, pp. 1-30 in Zootaxa 2298 (1)</i> on pages 16-20, DOI: 10.11646/zootaxa.2298.1.1, http://zenodo.org/record/5306757