Stachyops sebparri Bird, 2012, n.gen.
Creators: name: Bird, Graham J.
Publisher: name: Zenodo
Year: 2012
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Malacostraca
Tanaidacea
Nototanaidae
Stachyops
Stachyops sebparri

description: Stachyops sebparri n.gen. n.sp.
Figs 1–3, 4 B
Material examined. Holotype: preparatory ♀, GJB-RW/28-11 [Te Papa CR.023392]: North end of Worser Bay, Karaka Bays, Miramar Peninsula, Wellington, North Island, New Zealand; LWS, Corallina turf/sand, 41.3084°S 174.8325°E (retrieved from Google Earth), 20 March 2011; coll. G.J. Bird & R. Webber.
Paratypes: two preparatory ♀♀, one ovigerous ♀, GJB-RW/17-11 [CR.023393; one of the preparatory ♀♀ partly dissected on microslide CR.023394]: bay on Kaitawa headland, Whitireia Park, Porirua, North Island, New Zealand; ELWS, mixed algal turf and holdfasts, 41.0893°S 174.8503°E (retrieved from Google Earth), 20 February 2011; coll. G.J. Bird & R. Webber.
Type locality. Worser Bay, details as for holotype.
Etymology. This species is named for Sebastian Parr, of Christchurch, New Zealand. Sebastian has had a lifelong interest in past and present biodiversity, and approves cadastral survey plans for the rebuild of Christchurch following the devastating earthquakes of 2010/11.
Description [excluding generic diagnostics]. Female: Habitus (Fig. 1 A) fairly slender, 6.7 times ltb; length 1.22–1.44 mm. Cephalothorax (Figs 1 B–C) 1.2 times ltb, as long as pereonites 1–2; rostrum weakly produced, triangular, with scattered pigment between eyes; with lateral seta immediately posterior to eyelobe, eyelobes acutely pointed. Pereon with pereonite-1 shortest, weakly trapezoidal, others with convex lateral margins, pereonite-5 longest, pereonites 1–6 0.35, 0.53, 0.68, 0.75, 0.81, and 0.63 times as long as broad respectively; all with lateral seta. Pleon as long as pereonite-6 and half of pereonite-5 together, about 17% of body length, epimera (Fig. 1 D) with long seta. Pleotelson (Fig. 1 E) 0.7 times as long as broad, with weakly produced apex, and four dorsal and lateral setae.
Antennule (Fig. 1 F) about 0.8 times as long as cephalothorax; article-1 compound, 64% of total length, three times ltb, distolateral seta as long as articles 2–3 together; article-2 1.3 times ltb; article-3 as long as article-2, with one terminal aesthetasc; other setation as figured. Antenna (Fig. 1 G) article-1 short, naked; article-2 as long as broad, no larger than article-3, with stiff superodistal seta; article-3 similar to article-2; article-4 six times ltb, with distal simple seta and one PSS; article-5 half length of article-4, with distal seta; article-6 small, with four setae.
Labrum (Fig. 2 A) hood-like, distally setulate. Mandibles (Figs 2 B–E) left mandible lacinia broad, distally crenulate, directed anteriorly, incisor with several denticles; right mandible body and proximal of bifid incisor broad, with crenulate dorsal margin. Labium (Fig. 2 F) outer lobes much reduced, naked. Maxillule (Fig. 2 G) endite slender, with eight (?) terminal spines, proximal two bifid. Maxilla (Fig. 2 H) subovate, about two-thirds length of maxilliped bases. Maxillipeds (Fig. 2 J) with bases together weakly cardioid, 1.3 times ltb, each with long seta; endites unfused, strongly flared, distolateral margin setulate, mesial tubercles of frontal margin unequal and offset; palp article-1 with strongly oblique articulation with article-2; article-2 inner margin with three unequal setae; article-3 with four inner setae; article-4 with one subdistal and four terminal setae. Epignath not recovered.
Cheliped (Figs 1 C, 2K) sclerite naked; basis 1.5 times ltb, with superolateral seta; merus unremarkable; carpus 1.8 times ltb; chela 2.3 times ltb, shorter and narrower than carpus, palm 1.7 times ltb, twice as long as fixed finger, with one seta near articulation with dactylus and one seta on inner face; fixed finger incisive margin with about three distal teeth, terminal spine slender; dactylus naked.
Pereopod-1 (Fig. 3 A) coxa with long seta; basis five times ltb, with one superoproximal seta; ischium naked; merus twice as long as broad, with strongly oblique articulation with carpus, naked; carpus as long as merus, naked; propodus as long as merus and carpus together, with superodistal seta; dactylus about half as long as unguis, together as long as propodus. Pereopod -2 (Fig. 3 B) smaller than pereopod-1, coxa similar [with oostegite bud in preparatory female; basis with superior PSS; ischium naked; merus 1.5 times ltb, naked; carpus 1.6 times ltb; inferodistal inner spine smaller; propodus thinner and slightly longer than carpus, superior margin with combs, with distolateral seta and inferodistal spine; dactylus with accessory spine, with unguis shorter than propodus. Pereopod-3 (Fig. 3 C) similar to pereopod-2 but slightly smaller.
Pereopod-4 (Fig. 3 D) larger and more robust than pereopods 1–3; coxa naked, [with oostegite bud in preparatory female]; basis 2.6 times ltb, naked; ischium with seta; merus 1.5 times ltb, with two inferodistal spines; carpus subrectangular, longer than merus, twice as long as broad, largest distal spine just longer than carpus width; propodus just longer than carpus, with superodistal spine and two inferodistal spines; dactylus and unguis distinct, together just shorter than propodus. Pereopod-5 (Fig. 3 E) similar to pereopod-4. Pereopod-6 (Fig. 3 F) similar to pereopods 4–5 but propodus with two additional superodistal spines.
Pleopod (Fig. 3 G) peduncle just longer than broad, naked; endopod ovate, 2.4 times ltb, inner margin with distal seta, terminal fringe of six setae; exopod larger than endopod, 2.1 times ltb, with proximal seta and distal fringe of nine setae.
Uropod (Fig. 1 H) peduncle as long as broad; exopod twice as long as peduncle, over three-quarters length of endopod, segments equally long; endopod segments equally long; setation as figured.
Remarks. Stachyops sebparri n.gen. n.sp. has only been recorded from two sites in the Cook Strait region of North Island among algal encrusts, including erect corallines, in the low eulittoral zone. With it in the same samples were Parakonarus kopure, Zeuxoides rimuwhero, and an undescribed species of Metapseudes Stephensen, 1927, although several other Paratanais and apseudomorphan species are sympatric in the same habitats. Its apparent scarceness may be an example of ‘pseudo-rarity’ (Gaston 1994: 53) but it may be genuinely rare or have a specific niche, such one of the sessile epifauna (bryozoans, sponges, tunicates etc.), which is only sampled fortuitously among algal turfs or holdfasts. As its relatively narrow, piercing-crushing, mandibular molars are quite dissimilar from the broad triturative types seen in most other New Zealand rocky shore tanaidomorphan genera (Zeuxoides Sieg; Atemtanais Bird, 2011; Paratanais Dana; Parakonarus Bird, 2011; and Zeuxo Templeton) and are closer to those of many deep-sea forms, a diet other than algae might be presumed for Stachyops n.gen., which could support the previous inference about its niche specificity. Its small size, similar that of the recently-described Heterotanoides muimui Bird, 2012, is also a factor in its apparent scarcity.
description: Published as part of Bird, Graham J., 2012, Stachyops, a new nototanaid genus (Crustacea: Peracarida: Tanaidacea) from New Zealand, with remarks on nototanaid and tanaissuid phylogeny, pp. 1-10 in Zootaxa 3572 on pages 3-7, DOI: 10.5281/zenodo.212006