Cryptocopoides nobilis, Błażewicz-Paszkowycz, Magdalena & Bamber, Roger N., 2011

Błażewicz-Paszkowycz, Magdalena & Bamber, Roger N., 2011, Tanaidomorph Tanaidacea (Crustacea: Peracarida) from Mud-Volcano and Seep Sites on the Norwegian Margin, Zootaxa 3061, pp. 1-35 : 10-14

Cryptocopoides nobilis sp. nov.

( Figs 5–7 )

Material examined. Holotype, Ƥ (MNHN-IU- 2010-2834), ARK 22-1, PL170-7, CL21, HMMV, 72°00.34ʹN 14°43.22ʹE, 1259 m, 03/07/2007. Paratypes: 1Ƥ (dissected,3 slides), locality the same as holotype (MNHN-IU- 2010-2835); 1 manca (MNHN-IU- 2010-2836), Vicking, PL272-2, GCL 1, G11 Nyegga, 64°39.996ʹN 05°17.346ʹE, 736 m, 25/05/2006; 1Ƥ (MNHN-IU- 2010-2837), Vicking, KGSssech-1, Storegga NE, 64°45.281ʹN 05°06.217ʹE, 742 m, 23/05/2006; 32 specimens (MNHN-IU- 2010-2838), ARK 22-1, PL170-7, CL12, HMMV, 72°00.34ʹN 14°43.22ʹE, 1259 m, 03/07/2007; 4 specimens (MNHN-IU- 2010-2839), ARK 22-1, PL170-7, CL22, HMMV, 72°00.34ʹN 14°43.22ʹE, 1259 m, 03/07/2007.

Description of female. Body ( Fig. 5 A, B) compact, holotype 2.9 mm long, 5.4 times as long as wide. Cephalothorax subcircular, as long as wide, about as long as pereonites 1 to 3 together, with slight triangular rostrum, naked, eyes absent, small eyelobes present. Six free rectangular pereonites with convex sides; pereonites 1 shortest, one-third as long as cephalothorax; pereonites 2 and 3 subequal in length, 1.3 times as long as pereonite 1; pereonites 4 and 5 longest, half as long as cephalothorax; pereonite 6 just longer than pereonite 1 (all pereonites respectively 2.8, 2.1, 2, 1.6, 1.4 and twice as wide as long). Pleon of five free subequal pleonites bearing pleopods, each pleonite four times as wide as long. Pleotelson semicircular, as wide as long, nearly three times as long as last pleonite, with slight extension bearing two setae mid-posteriorly ( Fig. 7 I). Slight rounded sternal processes on pereonite 1 and on pleonites ( Fig. 5 C).

Antennule ( Fig. 6 A) proximal article stout, 1.3 times as long as wide, 0.7 times as long as distal three articles together, tapering, with inner proximal and outer distal tufts of three penicillate setae and one outer distal simple seta longer than second article; second article longer than wide, tapering, 0.6 times as long as first article, with three penicillate and one simple outer distal setae; third article just longer than wide, one-third as long as second article, with single inner and outer simple distal setae; fourth article slender, extended by inner distal triangular apophysis, 0.7 times as long as proximal article, with four distal setae and one aesthetasc.

Antenna ( Fig. 6 B) of six articles, proximal article compact, fused to cephalothorax, naked; second article twice as long as wide, 1.4 times as long as first article, with stout dorsodistal seta; third article as long as first article, just longer than wide, 0.6 times as long as second article, with stout dorsodistal seta; fourth article longest, curved, three times as long as third article and four times as long as wide, with five penicillate and one simple distal setae; fifth article 0.4 times as long as fourth with one distal seta; sixth article minute with five distal setae.

Labrum ( Fig. 6 C) hood-shaped, distally densely setose. Left mandible ( Fig. 6 D) with five rounded teeth on pars incisiva, wide, crenulate lacinia mobilis with extended outer margin, pars molaris stout with blunt, rounded marginal “teeth” and group of slender pointed spinules directed proximally. Right mandible ( Fig. 6 E) as left but without lacinia mobilis although with setose ridge, pars incisiva with wider teeth. Labium ( Fig. 6 G) simple, distally finely setose, without palp. Maxillule ( Fig. 6 F) endite with eight slender distal spines and finely setulose outer distal margin, palp ( Fig. 6 F’) with two unequal distal setae. Maxilla ( Fig. 6 F) simple, rounded, naked. Maxilliped ( Fig. 6 H) palp first article naked, second article with one fine outer distal seta, inner margin with two simple and one finely-denticulate setae, longest seta longer than third article; third article distally with four inner setae, longest seta longer than fourth article, fourth article with three distal and one outer subdistal simple setae and one distallydenticulate inner subdistal spine, inner distal margin with microtrichia; basis with single, long seta not reaching margin of endites; endites unfused, distally with two small setae and two small oval tubercles.

Cheliped ( Fig. 7 A) sclerite with rectangular attachment to basis, narrowly-rounded posteriorly, dorsally inserted, not fused with carapace; basis about as long as wide; merus subtriangular with single ventral seta; carpus with rounded dorsoproximal extension, 1.5 times as long as wide, with two mid-ventral setae, one mid-dorsal seta and finely denticulate proximal dorsal margin; propodus slender, as long as carpus, palm 1.4 times as long as wide, comb-row of three spines; fixed finger 0.6 times as long as palm with two ventral setae, two setae on cutting edge which bears rounded crenulations in distal half; dactylus with fine proximal seta, cutting edge with two stout spinules.

Pereopod 1 ( Fig. 7 B) coxa without apophysis, with seta; basis slender, 7.4 times as long as wide, with dorsoproximal penicillate seta; ischium with one ventral seta; merus one-third as long as basis, with two ventrodistal setae; carpus 1.4 times as long as merus with one dorsodistal and two ventrodistal setae; propodus 1.2 times as long as carpus, with single ventrodistal and dorsodistal setae; dactylus half as long as slender unguis, both curved, together 0.9 times as long as propodus. Pereopod 2 ( Fig. 7 C), coxa similar to pereopod 1, basis seven times as long as wide, with three dorsoproximal penicillate seta; ischium with one ventral seta; merus 0.75 times as long as carpus, with two ventrodistal setae; carpus with one ventrodistal spine and two dorsodistal setae; propodus 1.2 times as long as carpus, with longer ventrodistal and two shorter dorsodistal setae, and slight dorsodistal pointed apophysis; dactylus with longer unguis 0.9 times as long as propodus. Pereopod 3 ( Fig. 7 D) similar to pereopod 2, but merus with two fine ventrodistal spines.

Pereopod 4 ( Fig. 7 E) coxa distinct, naked; basis stouter, clavate, 3.2 times as long as maximum width, with three penicillate setae in proximal half; merus 0.7 times as long as carpus, with two slender ventrodistal spines; carpus with one ventrodistal spine, single inner and outer dorsodistal spines and one dorsodistal seta; propodus 1.3 times as long as carpus, with two ventrodistal setae and one dorsodistal seta; dactylus and shorter unguis not fused, curved, 0.7 times as long as propodus. Pereopod 5 ( Fig. 7 F) as pereopod 4, but basis without penicillate setae, ischium with two ventral setae, carpus with one marginal, one inner and one outer distal spines in ventral half, one dorsodistal spine and one dorsodistal spatulate seta ( sensu McLelland 2007 ); propodus with dorsal penicillate seta. Pereopod 6 ( Fig. 7 G) as pereopod 5, but basis with two penicillate setae, propodus with two dorsodistal setae.

Pleopods ( Fig. 7 H) all alike, with naked basis, endopod shorter than exopod, endopod and exopod with 3 and 4 distal setae respectively.

Uropod ( Fig. 7 I) biramous, stout basis naked; exopod of two segments, just longer than proximal endopod segment, first segment with single, long distal seta, second segment with one longer and one shorter distal setae; endopod longer than exopod, of two segments, first segment naked, second segment with one penicillate and five unequal simple setae distally.

Male unknown.

Etymology. From the Latin, nobilis , meaning ‘noble’, named indirectly after the mud-volcano at which it was found: Håkon is a Scandinavian name meaning ‘noble’. The volcano is named after the RV Håkon Mosby, itself named after Håkon Mosby (1903–1989), who was a key figure in the development of oceanographical research in Norway.

Remarks. Cryptocopoides nobilis sp. nov. and C. pruinosus are immediately distinct from the other species in having a conical proximal antennular article which is about 1.5 or less times as long as wide (1.7 times as long as wide in C. pacifica ; about twice as long in the other two species), as well as a proportionately longer pleotelson, and a carapace only just longer than pereonites 1 to 3 together. C. nobilis is distinct from C. pruinosus in having two segments in both rami of the uropod (only one segment in each ramus in C. pruinosus , although with a suggestion of incipient articulation of the exopod), and in the lack of a dorsoproximal spine on the dactylus of the posterior pereopods, inter alia. C. nobilis is most evidently distinguished from the potentially sympatric C. arctica in its less elongate carapace, as long as wide compared with distinctly longer than wide in Hansen’s species, and about as long as pereonites 1 to 3 together, compared with nearly as long as pereonites 1 to 4 in C. arctica .

Cryptocopoides nobilis was taken over a depth range of 736 to 1272 m, at the HMMV, Storegga and Nyegga sites.

Figures

FIGURE 5. Cryptocopoides nobilis sp. nov., female, A, lateral; B, dorsal; C, pleon, lateral, with pleopods removed. Scale lines = 1 mm.

FIGURE 6. Cryptocopoides nobilis sp. nov., female, A, antennule; B, antenna; C, labrum; D, left mandible; E, right mandible; F, maxilla and maxillule endite, with F’, maxillule palp; G, labium; H, maxilliped. Scale lines = 0.1 mm.

FIGURE 7. Cryptocopoides nobilis sp. nov., female, A, cheliped; B to G, pereopods 1 to 6 respectively; H, pleopod; I, uropod. Scale lines = 0.1 mm.