Ensayara kermadecensis Kilgallen 2009, sp. nov.

• Main Author: Kilgallen, Niamh M.
• Format: Text
• Language: unknown
• Published: Zenodo 2009
• Subjects: Biodiversity; Taxonomy; Animalia; Arthropoda; Malacostraca; Amphipoda; Endevouridae; Ensayara; Ensayara kermadecensis; Lowry; New Zealand; Snares Islands
• Online Access: https://dx.doi.org/10.5281/zenodo.5314265; https://zenodo.org/record/5314265

Ensayara kermadecensis sp. nov. (Figures 1–3) Type material. Holotype, sex undetermined, 2.5 mm, NIWA 50185, Giggenbach submarine volcano, Kermadec Volcanic Arc, 30º02.2’S, 178º42.65’W, 160 m (KOK0505 /42), collected with the hydrothermal vent mussel Bathymodiolus sp. by submersible Pices V . Paratypes, 19 specimens, 1.8–3.0 mm, NIWA 48674, from the same locality. Etymology. Named for the Kermadec Arc from where this material was collected. Diagnosis. Antenna 1 peduncle with 3 distinct articles, article 3 long. Lateral cephalic lobes subquadrate, not downward-pointing. Eyes present. Pereopod 3 propodus largely expanded and strongly subchelate. Pereopod 7 basis posteroventral margin excavate. Description of holotype. Antenna 1 subequal to antenna 2; peduncle with 3 distinct articles, articles 2–3 not telescoped; flagellum 7-articulate, article 1 slightly longer than article 2; accessory flagellum 3-articulate. Antenna 2 less than 40% of body length; flagellum 6-articulate. Calceoli absent. Eyes present, large, oblong. Lateral cephalic lobes subquadrate. Epistome and upper lip fused. Mandible incisor broad, smooth; lacinia mobilis absent from both mandibles; molar a setose flap; palp attached slightly proximally, article 3 slightly greater than half length of article 2. Maxilla 1 outer plate with setal-teeth in a modified 6/5 arrangement; palp present, 2 articulate. Maxilliped palp 4-articulate, article 4 well developed; outer plate poorly developed, not reaching palp article 3, apical margin weakly crenated; inner plate well developed, greater than half the length of outer plate. Gnathopod 1 simple; coxa 1 large, about as long as coxa 2, slightly tapering posterodistally, rounded distally; ischium moderately elongate, about 1.8 × as long as broad; merus short; carpus very short, distinctly shorter than propodus; propodus margins tapering; dactylus without accessory tooth. Gnathopod 2 minutely chelate; carpus twice as long as propodus. Pereopod 3 highly distinctive of genus; propodus largely expanded, strongly subchelate. Coxa 4 with moderately developed posterior lobe; merus weakly expanded, subequal in length to carpus; carpus slender, slightly shorter than propodus; propodus slender; dactylus about half propodus length. Coxa 5 produced into an anterior lobe; basis about as long as broad, merus expanded posteriorly, subequal in length to carpus; carpus short, much shorter than propodus; dactylus about 0.4 × propodus length. Pereopod 6 basis distinctly longer than broad; merus expanded posteriorly. Pereopod 7 basis distinctly longer than broad, posteroventral margin excavate; posterodistal corner slightly produced, just reaching merus; merus slightly expanded posteriorly, slightly shorter than carpus; carpus slender, distinctly shorter than propodus; propodus slender; dactylus about 0.4 × propodus length. Gills on pereonites 2–6. Epimeron 1 anterodistal corner broadly rounded. Epimeron 3 posterodistal corner quadrate. Urosomite 1 without distinct dorsal depression. Uropod 1 peduncle longer than rami; rami subequal in length. Uropod 2 peduncle subequal to rami; rami subequal in length, inner ramus without marginal constriction. Uropod 3 peduncle subequal to rami; outer ramus 2-articulate; inner ramus slightly shorter than outer ramus. Telson distinctly longer than broad, entire. Length. 1.8–3.0 mm. Distribution. New Zealand: Giggenbach submarine volcano, Kermadec Volcanic Arc; 160 m. Ecology. A relatively shallow-water species associated with seamounts, possibly commensal on the vent mussel Bathymodiolus sp. (Mollusca, Bivalvia, Mytiloida). Remarks. Ensayara kermadecensis sp. nov. is markedly similar to E. iara Lowry & Stoddart, 1983 (type locality: Snares Islands), differing only in the shape of the lateral cephalic lobes (subacute in E. iara , subquadrate in E. kermadecensis ); the relative length of article 3 of the mandibular palp, which is more than half the length of article 2 in E. kermadecensis , but only about 0.35 × article 2 in E. iara the maxillipedal palp, which is distinctly more slender, and article 4 of which bears an unguis in the new species that is not present in E. iara and the relative length of the inner ramus to the outer ramus of uropod 3, which is proportionally longer in the E. kermadecensis . : Published as part of 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) on pages 2-6, DOI: 10.11646/zootaxa.2298.1.1, http://zenodo.org/record/5306757 : {"references": ["Lowry, J. K. & Stoddart, H. E. (1983) The shallow-water gammaridean Amphipoda of the subantarctic islands of New Zealand and Australia (Lysianassoidea). Journal of the Royal Society of New Zealand, 13 (4), 279 - 294."]}