Alexandrella setosa Serejo, 2014, sp. nov.
Creators: name: Serejo, C. S.
Publisher: name: Zenodo
Year: 2014
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Malacostraca
Amphipoda
Stilipedidae
Alexandrella
Alexandrella setosa

description: Alexandrella setosa sp. nov.
(Figs 2–5)
Material examined. Holotype, male, 17.9 mm, superstation 7, serial number 1030, Walvis Ridge Sector (WRS), 29o29.87’S 0 1o 10.06’E, 4120 m, MNRJ 23520. Allotype, female, 18 mm, same as type locality, MNRJ 23763. Paratypes: 2 females, 19 mm, 19.3 mm, same as type locality, MNRJ 23764.
Etymology. from the Greek Setose that corresponds to the densely setose condition of gnathopods 1 and 2.
Diagnosis. Mandible, incisors fully toothed, molar absent; maxilla 1 outer plate with 36–40 setal-teeth. Gnathopods 1–2 subchelate, carpus and propodus densely setose. Pleonites 1–3 and urosomite 1 strongly toothed.
Description. Based on holotype, male 17.9 mm, MNRJ 23520. Eyes absent. Upper lip strongly asymmetrical. Mandible, incisor fully toothed; molar absent; left lacinia mobilis very large and toothed; right lacinia much smaller than left one, slightly toothed palp 3-articulated. Lower lip without inner lobe. Maxilla 1, palp 2- articulated, second article widening distally, with 28–30 distal robust setae and 9–10 sub distal slender setae; outer plate with 36–40 setal teeth; inner plate setose, with 5–6 basal pappose setae. Maxilla 2 outer plate slightly wider than inner plate; inner plate with several basal pappose setae. Maxilliped outer plate strongly exceeding palp, serrate medially; inner plate extending past distal margin of palp article 1; palp with marginal setae.
Coxa 1 wider than coxae 2–3. Coxa 4 excavated posteriorly, ventral margin rounded. Gnathopods 1–2 subchelate, palm excavate proximally, broadly rounded distally, with 10–11 robust setae at palm corner; propodus and carpus densely setose; dactylus slightly curved, inner margin with sparse setae. Basis of pereopods 5–6 with medial ridge. Basis of pereopod 7 expanded proximally forming a posterior lobe, posterodistal lobe rounded.
Pleonites 1–3 and urosomite 1 strongly toothed. Epimeron 2 with posteroventral tooth. Epimeron 3 subquadrate. Uropod 1, peduncle apparently longer than rami, which are broken at tip. Uropod 2 peduncle subequal to inner ramus; inner ramus 1.6 × outer ramus length; both rami with marginal row of setae on medial side. Uropod 3 peduncle much shorter than rami, which are broken at tip. Telson emarginated, as long as wide.
Female. Gnathopods 1–2 subchelate, palm slightly oblique, with 3 robust setae; propodus and carpus densely setose; dactylus straight and distinctly serrate. Oostegites present on pereopods 2–5.
Distribution. Atlantic Ocean: Walvis Ridge, 29o29.87’S 0 1o 10.06’E, 4120 m.
Remarks. Alexandrella setosa sp. nov is closely related to A. subchelata as both species present gnathopods 1–2 subchelate, which is a unique character within the genus. The new species can be distinguished from A. subchelata by the maxilla 1 outer plate with 36–40 setal teeth (versus 26 setal-teeth); maxilla 1 palp with 28–30 robust setae (versus 16 robust setae); gnathopods 1–2 densely setose on facial margins of carpus and propodus and pleonites 1–3 dorsally with well developed pointed teeth.
description: Published as part of Serejo, C. S., 2014, A new species of Stilipedidae (Amphipoda: Senticaudata) from the South Mid- Atlantic Ridge, pp. 133-140 in Zootaxa 3852 (1) on pages 135-137, DOI: 10.11646/zootaxa.3852.1.6, http://zenodo.org/record/229401