Larsenotanais kamchatikus, Błażewicz-Paszkowycz, Magdalena, 2007

Błażewicz-Paszkowycz, Magdalena, 2007, Family Nototanaidae Sieg, 1976 and Typhlotanaidae Sieg, 1984, Zootaxa 1599, pp. 101-120 : 113-115

Larsenotanais kamchatikus n.sp.

Figures 7–9

Material examined. Holotype, female ( KMNH IvR 500.192), station XR-5, 42°23.83– 42 °22.06’N 145°31.06’– 145°27.70’E, 3145–3265 metres, 16 September 2001. Paratypes: 2 females (1 dissected on slides; KMNH IvR 500.193), same locality.

Diagnosis. Body six times as long as wide; pereonite 1 shortest, half as long as pereonite 2, pereonites 2– 5 subequal.

Etymology. The name is given from the type locality.

Description: Non-ovigerous female

Body ( Figs 7 A,B). 6.5 times as long as wide.

Carapace. As long as wide, tapering proximally.

Pereonites. Pereonite 2 almost twice as long as as pereonite 1. Pereonites 2–5 subequal, 1.5 as wide as long. Pereonite 6 little shorter than pereonite 5, 1.7 times as wide as long.

Pleon. 1.7 times as long as carapace.

Pleotelson. Gently rounded; caudal projection well developed, with two setae.

Antennule ( Fig. 8 A). Article 1 about three times as long as wide, 1.3 times as long as article 2 and 3 combined, with five simple setae on inner margin, outer margin with three groups of pinnate setae, and with one simple seta just reaching tip of article 3. Article 2 0.7 times as long as article 3, with two simple seta distally. Article 3 with four long and two short setae terminally.

Antenna ( Fig. 8 B). Articles 2 and 3 subequal, each with short seta. Article 4 with fusion line at middle, six as long as wide, with two long, one short and two pinnate setae distally and sub-distally. Article 5 half as long as article 4, with one simple seta distally. Article 6 with four long and one short terminal setae.

Mouthparts. Labrum lost during dissection. Mandibles ( Fig. 8 C, D) molar well developed with regular tubercles and teeth on distal edges; lacinia mobilis well developed, serrated; right mandible ( Fig. 8 D) with strong tooth and serrated upper margin. Maxillule ( Fig. 8 E) inner endite with seven terminal setae; palp lost during dissection. Maxilla lost during dissection. Labium ( Fig. 8 F) with few setae on outer corner of inner lobe; outer lobe with small setae. Maxilliped ( Fig. 8 G) bases with simple seta exceeding over endite; each endite armed with two setae and two tubercles on distal margin; palp article 1 naked; article 2 wedge-shaped, with three setae (two 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. Epignath not observed.

Cheliped ( Fig. 9 A). Basis 1.8 times as long as wide with one seta disto-dorsally. Merus wedge-shaped with seta ventrally. Carpus three times as long as wide, with two simple and one minute setae ventrally and two setae dorsally. Chela little longer than carpus, almost four times as long as wide, with two seta near cheliped insertion (on inner and on outer side). Fixed finger with three setae on inner margin and two simple setae ventrally. Dactylus almost straight.

Pereopod 1 ( Fig. 9 B). Of walking type. Coxa with seta. Basis as long as merus, carpus and half of propodus combined, with two setae dorsally and one seta ventrally along article. Ischium with one simple seta. Merus slightly longer than carpus, with two setae distally. Carpus little shorter than merus, with three short setae distally. Propodus 1.5 as long as carpus with two setae dorsally and one ventral seta sub-distally; unguis twice as long as dactylus. Unguis and dactylus combined 0.8 as long as propodus.

Pereopod 2 ( Fig. 9 C). Of walking type. Basis little half as long as merus, carpus and propodus combined, with two simple and one pinnate 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 minute spiniform seta ventrally. Dactylus shorter than unguis, both half as long as propodus.

Pereopod 3 ( Fig. 9 D). Similar to pereopod 2.

Pereopod 4 ( Fig. 9 E). Of clinging type. Basis wide, 2.5 as long as wide, with one simple seta proximally and one pinnate seta disto-ventrally. Ischium with two setae. Merus subequal to carpus, with two subdistal spiniform setae ventrally. Carpus with hooks distally, one sensory seta dorsally, and with rounded, small (less than half as long as article) prickly tubercles ventrally. Propodus six times as long as wide, with two spiniform setae ventrally and with one seta shorter than dactylus proximally. Dactylus tipped by simple unguis; dactylus and unguis 0.7 times as long as propodus.

Pereopod 5 ( Fig. 9 F). Similar to pereopod 5.

Pereopod 6 ( Fig. 9 G). Similar to pereopod 5, but propodus with three terminal setae, as long as half of dactylus.

Pleopods ( Fig. 9 H). All pleopods similar. Exopod outer margin with sixteen plumose setae, inner margin with one plumose seta. Endopod armed with eleven plumose setae on outer margin; both rami with gap between proximal seta and others.

Uropod ( Fig. 9 I). Basal article about 0.3 as long as endopod; both rami uniarticulated. Endopod 1.3 times as long as exopod, with one pinnate and one simple setae at middle and with five setae terminally. Exopod with one short seta on outer margin and with one short and one long setae terminally.

Remarks: The new species is highly similar to Larsenotanais amabilis described by Błażewicz-Paszkowycz (2007) from the West Antarctic. If it were not pereonites 2 and 3, which are short in L. amabilis and almost square in L. kamchatikus , these two species might have been considered to be conspecific. The disjunct distribution of the species supports the belief that we dealing with two separate but congeneric species.

Distribution: Species known only from type locality.

Figures

FIGURE 7. Larsenotanais kamchatikus, adult female, A, lateral view; B, dorsal view. Scale = 0.1 mm.

FIGURE 8. Larsenotanais kamchatikus, female A, Antennule; B, Antenna; C, Left mandible; D, Right mandible; E, Maxillule; F, Labium; G, Maxilliped. Scale = 0.1 mm.

FIGURE 9. Larsenotanais kamchatikus, female A, Cheliped; B, Pereopod 1; C, Pereopod 2; D, Pereopod 3; E, Pereopod 4; F, Pereopod 5; G, Pereopod 6; H, Pleopod; I, Uropod. Scale = 0.1 mm.