Typhlotanais kyphosis, Błażewicz-Paszkowycz, Magdalena, Bamber, Roger N & Cunha, Marina R, 2011

Błażewicz-Paszkowycz, Magdalena, Bamber, Roger N & Cunha, Marina R, 2011, New tanaidomorph Tanaidacea (Crustacea: Peracarida) from submarine mud-volcanoes in the Gulf of Cadiz (North-east Atlantic), Zootaxa 2769, pp. 1-53 : 24-29

Typhlotanais kyphosis sp. nov.

Figs 14–16

Material. 1 female, Holotype ( BMNH.2010.408), Station CA 543, Captain Arutyunov mud-volcano, 35º39.688’N 07º19.981’W, 1345 m depth, mud breccia and H2S, Gravity corer, 06.08.2004; 1 female, paratype ( BMNH.2010.409), Station Fiu 403, Fiúza mud-volcano, 35º15.360’N 06º41.890’W, 385 m depth, mud breccia, Gravity corer, 15.07.2002; 2 specimens, paratypes ( BMNH.2010.410-411), Station Mer 569, Mercator mud-volcano, 35º17.917’N 06º38.717’W, 358 m depth, mud breccia, TV-grab, 25.07.2005; 1 female, 2 juveniles, paratypes ( BMNH.2010.412-414), 1 female, dissected, Station Ki 560, Kidd mud-volcano, 35º25.306’N 06º43.976’W, 498 m depth, mud breccia, Boxcorer, 08.08.2004; 1 female, paratype (retained), Station Mer 575, Mercator mud-volcano, 35º17.903’N 06º38.715’W, 355 m depth, mud breccia, Boxcorer, 26.07.2005; all coll. MRC.

Description. Body ( Fig. 14 A, B) elongate, holotype 2 mm long, 7.3 times as long as wide. Cephalothorax subrectangular, narrowing anteriorly, 1.2 times as long as wide, as long as pereonites 1 and 2 together, naked, small rostrum present, eyelobes absent. Pereonite 1 shortest, pereonites 2 to 5 subequal, twice as long as pereonite 1, pereonite 6 just shorter than pereonite 5 (all pereonites respectively 2.3, 1.4, 1.3, 1.2, 1.2 and 1.3 times as wide as long). All pleonites bearing pleopods; pleonites 1 to 4 subequal, four times as wide as long, pleonite 5 longer, 2.5 times as wide as long. Pleotelson curving ventrally, semicircular, as long as last two pleonites together, apically bilobed.

Antennule ( Fig. 15 A) proximal article 2.5 times as long as wide, 1.5 times as long as distal two articles together, outer margin with simple seta in proximal half and one simple and two penicillate setae distally; second article as long as wide, one-fifth as long as third article, with three distal setae; third article tapering, with four distal setae.

Antenna ( Fig. 15 B) of six articles, proximal article compact, naked; second article as long as wide, with stout dorsodistal seta; third article half as long as second, with stout dorsodistal seta; fourth article longest, five times as long as wide, with distal tuft of penicillate setae; fifth article half as long as fourth, with one long distal seta; sixth article minute with three longer and two shorter distal setae.

Labrum ( Fig. 15 C) rounded, hood-shaped, setose. Left mandible ( Fig. 15 D) with wide, crenulate lacinia mobilis, right mandible ( Fig. 15 E) without lacinia mobilis; pars molaris of both mandibles marginally with strong, rounded tooth-like protrusions and slender ventral teeth. Labium ( Fig. 15 G) simple, finely setose distally. Maxillule ( Fig. 15 F) endite with nine distal spines and sparse marginal setules, palp not recovered. Maxilla not recovered. Maxilliped ( Fig. 15 H) palp with numerous microtrichia; first article naked, second article with three inner setae, third article with four inner setae (two finely setulose), fourth article with five inner-distal setae (two finely setulose) and one outer subdistal seta; basis fused, heart-shaped, with single long seta not reaching distal margin of endites; endites distally with two simple setae and small rounded tubercles. Epignath ( Fig. 15 I) slender, linguiform, naked, distally recurved.

Cheliped ( Fig. 16 A) with rounded, naked basis 1.8 times as long as wide; merus subtriangular with single ventral seta; carpus relatively elongate, 2.2 times as long as wide, with two midventral setae and two smaller dorsal subdistal setae; propodus elongate, 2.35 times as long as wide, fixed finger half as long as propodus, with two ventral setae, three setae on cutting edge; dactylus with small proximal seta, two spinules on cutting edge.

Pereopod 1 ( Fig. 16 B) coxa without apophysis, with seta; basis slender, 4.5 times as long as wide, with fine setae along dorsal and ventral margins and dorsoproximal penicillate seta; ischium compact with one ventral seta; merus 0.8 times as long as carpus, and with one dorsodistal and two ventrodistal small setae; carpus with fine setae along distal half of dorsal margin, and in dorsodistal and ventrodistal tufts; propodus just longer than carpus, with three stouter and one fine distal setae; dactylus with proximal seta extending to more than half length of unguis, unguis twice as long as dactylus, both together just shorter than propodus. Pereopod 2 ( Fig. 16 C), coxa similar to pereopod 1, basis stouter, 2.9 times as long as wide, with sparser dorsal and ventral marginal setae; merus with small ventrodistal spine; propodus 1.4 times as long as carpus, with small dorsodistal and ventrodistal spines; seta on dactylus exceeding tip of unguis; dactylus and unguis subequal in length, two-thirds as long as propodus. Pereopod 3 ( Fig. 16 D) similar to pereopod 2, but carpus as long as merus and with ventrodistal spine, seta on dactylus not reaching end of unguis.

Pereopod 4 ( Fig. 16 E) of the clinging-type sensu Błażewicz-Paszkowycz (2007) , basis stout, 1.5 times as long as wide, without marginal simple setae but with two dorsal penicillate setae; ischium with two ventral setae; merus and carpus subequal, both with prickly-tubercles ventrally, merus with two short ventrodistal spines, carpus with ventrodistal molar spine and inner and outer distal setae; propodus 0.8 times as long as carpus, with dorsal penicillate seta, dorsodistal simple seta about half as long as dactylus, two ventrodistal spines and ventral microtrichia; dactylus with ventral microtrichia, together with short unguis as long as carpus. Pereopod 5 ( Fig. 16 F) as pereopod 4, but basis naked. Pereopod 6 ( Fig. 16 G) as pereopod 4, but propodus with three finely denticulate dorsodistal spines.

Pleopods ( Fig. 16 H) all alike, basis naked, endopod just shorter than exopod with one subdistal inner plumose seta and 17 outer plumose setae, proximal seta separated from remainder; exopod without inner seta but with 27 outer plumose setae, proximal seta separated from remainder.

Uropod ( Fig. 16 I) biramous, basis naked; both exopod and endopod of two segments; exopod as long as proximal endopod segment, proximal segment naked, distal segment with two unequal distal setae; endopod proximal segment with one simple and one penicillate distal setae, distal segment with one subdistal and four distal simple setae.

Male unknown.

Etymology. kyphosis is a dorso-ventral curvature of the spine (Gr kyphos = bent forward or humped), alluding to the unique dorsoventrally flexed pleotelson of the present species.

Remarks. Błażewicz-Paszkowycz (2007), in her comprehensive revision of the Typhlotanaidae , resolved the genus Typhlotanais sensu stricto to a single species, T. aequiremis ( Lilljeborg, 1864) , and presented a key to typhlotanaid genera and “morphogroups”. Using that key, the present species keys out to T. aequiremis , and thus is the second valid species of Typhlotanais sensu stricto. In addition to the keyed characters, it shares only with T. aequiremis the marginal setae on the basis and dorsodistally on the carpus of pereopod 1, as well as the conformation of the pleopods, pereopods and the presence of prickly tubercles.

Typhlotanais kyphosis sp. nov. is distinct from T. aequiremis in having two-segmented uropod rami (both rami in T. aequiremis have only one segment). The present species is also distinguished by the larger fifth pleonite, the stout dorsodistal setae on antennal articles 2 and 3, then length of the maxilliped basis seta, and the more attenuate carpi and the proportionately longer dactylus seta of pereopods 1 to 3.

Typhlotanais kyphosis also has quite distinct short spines on the merus, carpus and propodus of pereopods 2 and 3, and the “prickly tubercles” are larger and flatter than found in Typhlotanais sensu stricto, rather suggesting a link to the “ spinicauda group” of Błażewicz-Paszkowycz (2007). Rather than erect a monotypic genus for this somewhat intermediate species, we choose to leave it in Typhlotanais sensu stricto for now.

The new species was collected from the Captain Arutyunov mud-volcano (type-locality) in the deep-water field within the Portuguese margin, at 1345 m depth, and from the Fiúza, Kidd and Mercator mud-volcanoes in the El Arraiche field on the Moroccan margin, at 398 to 458 m depth, on muddy-substrata.

Genus Torquella Bła ż ewicz-Paszkowycz, 2007

Figures

FIGURE 14. Typhlotanais kyphosis sp. nov., A, Ƥ holotype, dorsal; B, Ƥ holotype, lateral. Scale line = 1 mm.

FIGURE 15. Typhlotanais kyphosis sp. nov., Ƥ paratype. A, antennule; B, antenna; C, labrum; D, left mandible; E, right mandible; F, maxillule; G, labium; H, maxilliped; I, epignath. Scale lines: A-B, = 0.1 mm; C-I = 0.01 mm.

FIGURE 16. Typhlotanais kyphosis sp. nov., A, cheliped; B to G, pereopods 1 to 6, respectively; H, pleopod; I, uropod. Scale line = 0.1 mm.