Abyssianira acutilobi Doti & Roccatagliata, 2006, n. sp.
Creators: name: Doti, Brenda Lía
name: Roccatagliata, Daniel
Publisher: name: Zenodo
Year: 2006
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Malacostraca
Isopoda
Paramunnidae
Abyssianira
Abyssianira acutilobi

description: Abyssianira acutilobi n. sp.
(Figs 3–5)
Material examined
Holotype: Stn. WHOI 245A, off the Río de la Plata estuary, 36º55´42´´S, 53º01´24´´W, 2707 m, 14 Mar 1971, brooding Ψ (AM P68699). Paratypes: same data as holotype, 1 manca (AM P72666); 1 immature Ψ (without pleotelson) and 1 manca (AM P72667).
Diagnosis
Frontal plate approximately as long as article 1 of antennulae, anterior margin strongly convex. Eyestalks large and triangular. Pereon with 4 groups of wart­like elevations. Coxal plates visible in dorsal view on pereonites 5–7 only. Bases of all pereopods strongly denticulate on both margins.
Description of brooding female holotype
Length: 3.6 mm (Fig. 3 A, B). Body width ~ 0.46 length, widest at pereonite 3. Head length ~ 0.36 width. Frontal plate length ~ 0.5 width, slightly concave in dorsal view, anterior margin strongly convex and with large denticles (many broken; Fig. 3 A, C). Eyestalks large and triangular with marginal denticles (many broken), longitudinal axis pointing forward at ~ 40º. Pereonites 1, 2, 6 and 7 with a pair of dorsolateral wart­like elevations; those on pereonite 6 minute; “warts” on pereonites 1, 2 and on pereonites 6, 7 contiguous, conforming 4 groups with 2 “warts” each. Coxal plates visible in dorsal view on pereonites 5–7 only. Free pleonite ~ 0.5 length of pereonite 7. Pleotelson width ~ 0.8 length, margins strongly denticulate.
Pereopod I (Fig. 5 B) basis longest article, with several simple setae and strong denticles on both margins. Ischium ~ 0.7 basis length, with 4 simple setae, dorsal margin with 5 hyaline lamellae. Merus cup­shaped, dorsal margin with 3 simple setae and 2 small teeth distally, ventral margin with 1 RS and 4 simple setae. Carpus ~ 0.8 ischium length, dorsal margin with 3 simple setae (1 half length along article and 2 distally), ventral margin with 2 RS, 8 simple setae and 4 hyaline lamellae. Propodus ~ 0.6 ischium length, dorsal margin with 4 simple setae (1 half length along article and 3 distally), ventral margin with 2 RS, 6 simple setae and 4 hyaline lamellae. Dactylus with 4 simple setae near distal end and 2 simple setae between unguis and supplementary claw, unguis subequal in length to dactylus, supplementary claw ~ 0.5 unguis length, ventral margin with 1 hyaline lamella.
Pereopods II–VII only bases remain, all with 1 row of strong denticles on each margin.
Operculum (Fig. 5 C) ovoid and pointed distally, width ~ 0.65 length, lateral margins with simple setae, ventral surface with 1 bulbous elevation proximally.
Uropod (Fig. 5 D) protopod half hidden; endopod with 3 simple setae subapically and 4 BS distally; exopod ~ 0.75 endopod length, with 2 long simple setae distally.
To preserve the head of the brooding female holotype intact the antennulae, antennae, and the mouthparts were described from one of the mancas (AM P72666):
Antennula (Fig. 4 A) article 1 with 1 BS and 2 simple setae; article 2 longest, with 4 BS near distal end; article 3 ~ twice longer than broad, with 1 simple seta; article 4 ~ 0.6 length of article 3, with 1 BS; article 5 glabrous; article 6 with 1 aesthetasc, 1 BS and 5 simple setae distally. In the holotype, as far as can be seen without dissecting, article 1 with marginal teeth and some additional longer setae (see Fig. 3 C).
Antenna (Fig. 4 B) article 1 missing and article 2 broken off; article 3 slightly wider than long, subequal in length to article 4; articles 4 and 5 with 2 distal simple setae; article 6 ~ 1.36 length of article 5, with 4 BS and 3 simple setae. Flagellum shorter than peduncle, with 7 articles (last two articles missing).
Left mandible (Fig. 4 C) incisor process with 5 cusps, lacinia mobilis with 4 cusps, spine row with 3 spines, molar process with teeth and 2 simple setae; palp slightly shorter than body of mandible: article 1 ~ 0.6 length of article 2, with 1 simple seta; article 2 with cuticular combs and 2 pectinate setae; article 3 smallest, ~ 0.65 length of article 1, with cuticular combs and 2 pectinate setae. Right mandible as left except for: lacinia mobilis absent, spine row with 4 spines.
Maxillula (Fig. 4 D) lateral lobe with 12 spine­like setae (some of them serrate) and 1 simple seta on distal margin; mesial lobe with 5 setae (some of them setulate) on distal margin.
Maxilla (Fig. 4 E) lateral and middle lobes with 4 unequal pectinate setae on distal margin, mesial lobe with 3 simple setae (with a pore­bearing tip), 2 pectinate setae, 3 plumose setae, and many short simple setae distally.
Maxilliped (Fig. 5 A) endite with 2 coupling hooks; distal margin with 3 plumose and 2 pectinate setae; ventral surface with 2 fan setae distally; dorsal surface with 3 pectinate, 1 plumose, and several small simple setae distally. Epipod elongate, ~ 0.85 palp length, width/length ratio ~ 0.5. Palp ~ 0.89 maxilliped axial length, articles 2 (and 3) narrower than endite.
Distribution
Found at a single station off the Río de la Plata estuary, depth 2707 m (Fig. 2).
Remarks
This species is easily distinguished by its large triangular eyestalks.
description: Published as part of Doti, Brenda Lía & Roccatagliata, Daniel, 2006, On the Atlantic species of the genus Abyssianira Menzies, 1956 (Isopoda: Asellota: Paramunnidae), pp. 1-35 in Zootaxa 1252 on pages 4-10, DOI: 10.5281/zenodo.173029