Meromonakantha nutae, 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 : 15-19

Meromonakantha nutae n. sp.

( Figs 5–7 )

Material examined: Holotype: one female, ( K 41353 ), ANT XXII/3 , PS 67/151-7-E, 61°45.52'– 61°45.42'S, 47°7.68'– 47°8.04'W, depth 1182–1185 m, epibenthic sledge, 21 Mar 2005 ; Paratypes three females (one damaged, one dissected on slides), ( K 41354 ), the same locality ; one female, ( K 41355 ), ANT XXII/3 , PS 67/150- 6-E, 61°48.70'– 61°48.57' S, 47°28.04'– 47°28.19' W, depth 1996– 1993 m, epibenthic sledge, 20 Mar 2005 .

Diagnosis: Carapace as long as pereonite-1 and a quarter of pereonite-2 combined. Antennule article-3 less than twice as long as article-2. Pereopods 1 and 2 propodus shorter than merus and carpus combined. Pleopod endopod with four-five, exopod with six-seven distal setae. Uropod exopod a little shorter than endopod, articles semifused.

Etymology: Nut is the Egyptian Goddess presented as an elongated woman bending over the Earth and touching the horizons with her toes and finger tips. The name reflects the bending body habitus of the preserved animal.

Description: Female 1.2 mm long ( Fig. 5A,B ). Body long, about eight times as long as wide; carapace as long as pereonite-1 and a quarter of pereonite-2 combined; pereonite-1 as long as pereonite-2; pereonite-2 subequal to pereonite-4; pereonite-3 subequal to pereonite-6, pereonite-5 longest; pleon as long as pereonites 5 and 6 combined.

Antennule ( Fig. 6A ): 0.6 times as long as carapace; article-1 stout, twice as long as wide, with long simple setae in middle and distal, and four pinnate setae along article; article-2 with two long simple setae distally; article-3 less than twice as long as article-2, with terminal small spur and three setae distally.

Antenna ( Fig. 6B ): Article-1 short; article-2 twice as long as article-3, with one long seta, article-3 with short simple seta; article-4 three times as long as wide, twice as long as article-5 with one simple and two pinnate setae distally; article-5 with single seta distally; article-6 short, with four simple setae.

Mouth parts: Labrum ( Fig. 6C ) hood-shaped, covered by numerous minute setae. Mandible ( Fig. 6D,E ) stout; molar process well-developed, with crenulated, well-calcified edges and with blunt teeth in lower margin; lacinia mobilis well-developed, crenulated. Maxillule ( Fig. 6F ) with eight terminal spiniform setae, palp ( Fig. 6 F’) with two terminal setae. Maxilla ( Fig. 6G ) subtriangular, naked. Maxilliped ( Fig. 6I ): coxa reduced; bases fused, a little longer than wide, with seta just reaching end of endites; endite with two setae and two tubercles distally; palp 4-articled: article-1 naked; article-2 with three setae on inner margin and one seta on outer margin; article-3 with four simple setae on inner margin; article-4 slender with five inner setae and small outer seta. Labium ( Fig. 6H ) 2-lobed, outer and inner lobe distal corner setose.

Cheliped ( Fig. 7A ): Basis 1.5 times as long as wide; merus with ventral seta; carpus almost 1.5 times as long as broad, with two dorsal setae and two long ventral setae; propodus and fixed finger little longer than carpus, about 2.5 times as long as broad; dactylus about half length of whole; fixed finger with three calcified teeth and three setae on inner margin, and two simple setae ventrally.

Pereopod-1 ( Fig. 7B ): Of walking type; coxa present; basis a little shorter than rest of articles combined, naked; ischium with one seta; merus equal to carpus, with one seta distally; carpus with four setae (one very small) distally; propodus little shorter than merus and carpus combined, with setae subdistal on dorsal and minute seta ventrally.

Pereopod-2 ( Fig. 7C ): Of walking type; coxa present; basis shorter than rest of articles combined, naked; ischium short, with one seta; merus as long as carpus with one seta distally; carpus with three setae distally; propodus little shorter than merus and carpus combined, with one seta ventrally and subdistal seta dorsally; dactylus and unguis combined as long as propodus.

Pereopod-3 ( Fig. 7D ): Similar to pereopod-2.

Pereopod-4 ( Fig. 7E ): Of walking type; basis shorter than rest of articles combined, three times as long as wide, naked; ischium with one seta; merus as long as carpus with two spiniform seta distally; carpus with two spiniform setae, one hook and one seta distally; propodus a little shorter than merus and carpus combined, with two spiniform setae ventrally, one pinnate seta dorsally and one dorso-distal seta; dactylus semifused with unguis, half as long as propodus.

Pereopod-5 ( Fig. 7F ): Similar to pereopod-4.

Pereopod-6 ( Fig. 7G ): Similar to pereopod-4 with three short setae on propodus distally (absent in drawn specimen).

Pleopods 1–5 ( Fig. 7H ): Basal article naked. Exopod with five setae on outer margin and one seta on inner margin. Endopod with eight setae. Both rami with most proximal seta separated by large gap from the others.

Uropod ( Fig. 7I ): Endopod two-articled, proximal article 0.6 times length of ramus, with five distal and subdistal setae. Exopod two-articled, articles semifused, a little shorter than endopod, with one outer seta near fusion line; distal article tipped by long seta.

Distribution: Antarctic: East off South Orkney Islands, at bathyal depths of 1182–1996 m.

Remarks: Meromonakantha nutae n. sp. is most similar to the North-Pacific M. setosa , having a relatively short carapace little longer than pereonite-1. The poor description of M. setosa and its lost types make any detailed comparison of the species impossible. The new species however has distinctly less slender chelae which are only twice as long as wide and semifused articles in the exopod of uropod.

Figures

FIGURE 5. Meromonakantha nutae n. sp., holotype, adult female. A) lateral view. Scale 0.1 mm.

FIGURE 6. Meromonakantha nutae n. sp., paratype. A) Antennule; B) Antenna; C) Labrum; D) Left mandible; E) Right mandible; F) Maxillule; F’) Palp; G) Maxilla; H) Labium; I) Maxilliped. Scale: A–C = 0.1 mm; D–H = 0.01 mm.

FIGURE 7. Meromonakantha nutae n. sp., paratype. 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.