Larsenotanais amabilis, Błażewicz-Paszkowycz, 2007

Błażewicz-Paszkowycz, Magdalena, 2007, Figure 6. Typhlotanais Compactus, Female A In Family Nototanaidae Sieg, 1976 And Typhlotanaidae Sieg, 1984, Zootaxa 1598, pp. 1-141 : 42-46

Larsenotanais amabilis n. sp.

( Figs 20–22 )

Material examined: Holotype: non-ovigerous female, ( K 41345 ), ANT XXII/2 , 60 °38.35'– 60° 38.12'S, 53°57.36'– 53° 57.49'W, depth 2893– 2893 m, EBS, 30 Jan 2002 ; Paratypes: two females (one dissected on slides), ( K 41346 ), the same locality ; one female, ( K 41438 ), ANT XXII/2 , PS 61/42-2, 59°40.29'– 59°40.42'S, 57°35.43'– 57°35,27'W, depth 3683– 3680 m, EBS, 27 Jan 2002 .

Diagnosis: as for the genus

Etymology: Amabilis (Lat.) = pleasant.

Description: Non-ovigerous female ( Figs 20A, B ). Body short, 4.4 times as long as wide. Carapace 0.8 times as long as wide, tapering proximally, rounded laterally; all pereonites wider than long, clearly rounded laterally; pereonites 1–3 subequal, three times as wide as long; pereonites 4–5 2.4 times as wide as long; pereonite-6 a little shorter than pereonite-5, 2.7 times as wide as long; pereonites 1 and 2 with small lateral seta; pleon 1.5 times as long as carapace; pleotelson gently rounded; caudal projection well-developed, with two setae.

Antennule ( Fig. 21A ): Article-1 about three times as long as wide, 1.4 times as long as article-2 and 3 combined, with five simple setae on inner margin, outer margin with one simple and two pinnate setae at middle and distally; article-2 0.6 times as long as article-3, with one long, simple seta and two pinnate setae distally; article-3 with three long and two short, terminal setae.

Antenna ( Fig. 21B ): Article-1 damaged during dissection; article-2 with one distal seta; article-3 naked; article-4 twice as long as article-5, with two simple and two pinnate setae distally; article-5 with simple seta distally; article-6 with four three terminal setae.

Mouth parts: Labrum lost during dissection. Mandible ( Fig. 21D,E ) stout; molar well-developed (Fig. E’), with regular tubercles on distal edges and three spines on lower margin; lacinia mobilis well-developed, crenulated. Maxillule ( Fig. 21F ) inner endite with eight terminal setae; palp lost during dissection. Maxilla ( Fig. 21G ) semi-oval. Labium ( Fig. 21H ) with bunch of setae on outer corner of inner lobe; outer lobe with small setae. Maxilliped ( Fig. 21I ) bases with simple setae reaching over endite; each endite armed with two middle setae and two tubercles on distal margin; palp article-1 naked; article-2 wedge-shaped, with three setae (one strongly serrated) on inner margin and one short, simple seta on outer margin; article-3 trapezoidal, with four setae on inner margin; article-4 with one simple seta on outer margin and five terminal setae (one shorter than others).

Cheliped ( Fig. 22A ): Basis 1.8 times as long as wide; merus wedge-shaped with seta ventrally; carpus three times as long as wide, with two simple setae ventrally and two short setae dorsally; carpal shield poorly developed; chela as long as carpus, three times as long as wide; fixed finger with three setae on inner margin and two simple setae ventrally; dactylus almost straight, with one short seta proximally.

Pereopod-1 ( Fig. 22B ): Of walking type; coxa present; basis as long as merus, carpus and half of propodus combined, with one medial seta dorsally; ischium with one simple seta; merus slightly shorter than carpus with three setae distally; carpus a little longer than merus with three setae distally and one minute seta subdis- tally on ventral margin; propodus slightly longer than carpus with one seta dorsally and one ventral seta subdistally; unguis 1.5 times as long as dactylus; unguis and dactylus combined 0.6 times length of propodus.

Pereopod-2 ( Fig. 22C ): Of walking type; coxa with one seta; basis little shorter than rest of articles combined, with one proximal setae dorsally; ischium with one seta; merus as long as carpus, with three setae distally; carpus as long as merus, with two simple setae, two minute and one spiniform setae distally; propodus with two subdistal setae dorsally (one longer than unguis) and one spiniform seta ventrally; dactylus shorter than unguis.

Pereopod-3 ( Fig. 22D ): Similar to pereopod-2.

Pereopod-4 ( Fig. 22E ): Similar to pereopod-5 (basis damaged).

Pereopod-5 ( Fig. 22F ): Of clinging type; basis wide, with two pinnate setae disto-ventrally; ischium with two setae; merus almost as long as carpus, with two subdistal spiniform setae and numerous combs of spines on ventrally; carpus with hooks distally, one sensory seta dorsally, and with rounded, small (less than half as long as article) prickly tubercles ventrally; propodus five times as long as wide, with one pinnate seta dorsally

and two spiniform setae ventrally, one seta reaching half dactylus; dactylus tipped by simple unguis; dactylus and unguis 0.7 times as long as propodus.

Pereopod-6 ( Fig. 22G ): Similar to pereopod-5, but propodus with three terminal setae not reaching half length of unguis.

Pleopods 1–5 ( Fig. 22H ): All pleopods similar; exopod outer margin with eight plumose setae, innermargin with one plumose seta; endopod armed with fourteen plumose setae on outer margin; both rami with gap between proximal seta and others.

Uropod ( Fig.22I ): Basal article less than half as long as endopod; both rami uni-articled; endopod 1.5 times as long as exopod, with pinnate setae on inner margin and six setae terminally; exopod and endopod two-articled; exopod tipped by short and long seta.

Distribution: West Antarctic, North Weddell Sea and North of South Shetland Island at depths ranging from 2893 to 3683 m.

Figures

FIGURE 20. Larsenotanais amabilis n. sp., holotype, female. A) dorsal view; B) lateral view. Scale = 0.1 mm

FIGURE 21. Larsenotanais amabilis n. sp., female paratype. A) Antennule; B) Antenna; C) Left mandible incisor; D) Right mandible; E) Molar details F) Maxillule; G) Maxilla H) Labium; I) Maxilliped. Scale: A, B = 0.1 mm; C-I = 0.01 mm.

FIGURE 22. Larsenotanais amabilis n. sp., female paratype. A) Cheliped; B) Pereopod-1; C) Pereopod-2; D) Pereopod-3; E) Pereopod-4; F) Pereopod-5; G) Pereopod-6; H) Pleopod; Uropod. Scale = 0.1 mm.