Hamatipeda trapezoida, 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 : 37-41

Hamatipeda trapezoida n. sp.

( Figs 17–19 )

Material examined: Holotype: non-ovigerous female, ( NMNH 1100137 ), r/v Eltanin Cr 4, Sta. 129., 61º46'– 61º48'S, 61º35'– 61º25'W, depth 3678–3861 m, Menzies Trawl, 2 Aug 1962 . Paratype: non-ovigerous female, ( K 41447 ), r/v Polarstern, ANT XIX/3-4 , PS 61/41-3, Sta. 41-3, 59° 22.24'- 59° 22.40' S, 60° 4.06'– 60° 3.99' W, depth 2375–2372, epibenthic sledge, 26 Jan 2002; ( K 41465 ) PS 61/129-7, 59°52.30'S, 59°57.63'W, depth 3614 m, Multi Corer, 23 Feb 2002.

Diagnosis: Pereonites 1–3 trapezoidal in shape (lateral margins of pereonites 1–3 not parallel). Setae on ventral margin of cheliped fixed finger not extending beyond the article. Uropod exopod almost as long as endopod.

Etymology: Named after the trapezoidal shape of pereonites 1–3.

Description: Female, with body length 5.7 mm ( Fig. 17 B, C ), body long, about ten times as long as wide. Carapace glabrous, narrow, 1.5 times as long as wide. Pereonites smooth; pereonites 1–3 wider anteriotly than posteriorly (trapezoidal shape); pereonite-1 0.75 times as long as pereonite-2; pereonites 2 and 3 subequal in length; pereonite-4 slightly shorter than pereonite-3, little longer than wide ( Fig. 17B ) or 1.7 as long as wide ( Fig. 17 A ) pereonite-5 slightly shorter than 4; pereonite-6 shortest. Pleonites 1–5 similar in size. Pleotelson rectangular, slightly tapering distally.

Antennule ( Fig. 18A ): Conical, three-articled; article-1 robust, about twice as wide as long, one simple medial seta, and two groups of pinnate setae distally and medially; article-2 0.25 times length of article-3, two simple setae and one pinnate seta distally; article-3 with four simple terminal setae.

Antenna ( Fig. 18B ): Article-1 damaged during dissection; article-2 with two simple setae; article-3 with one simple seta; article-4 almost 1.7 times as long as article-5, with three long simple setae and two distal, pinnate setae; article-5 with one simple distal seta; article-6 with six terminal setae.

Mouthparts: Labrum not found. Mandible ( Figs. 18C,D ) large, molar process well-developed, with crenulated edge; lacinia mobilis well-developed, with five teeth. Maxillule ( Fig. 18E ) with eight distal spiniform setae. Maxilla ( Fig. 18F ) oval. Labium ( Fig. 18G ) two-lobed; inner and outer lobe with a few setules distally. Maxilliped ( Fig. 18H ) bases elongated and fused, with one distal seta; each endite armed with two setae on distal margin; palp article-1 naked; article-2 wedge-shaped with one seta on outer margin and three setae on inner margin; article-3 with four setae on inner margin; article-4 slender (1.5 times as long as wide), with six terminal setae.

Cheliped ( Fig. 18J ) robust; basis slightly longer than wide; merus wedge-shaped, with one seta ventrally; carpus over 1.4 times as long as wide, with two long setae ventrally and two short setae dorsally (proximally and distally); chela narrower and shorter than carpus, twice as long as wide, with one seta at dactylus insertion; inner edge of fixed finger with three teeth and three setae in distal part; ventral edge with two long simple setae not extending beyond the article; dactylus slightly curved with one proximal seta.

Pereopod-1 ( Fig. 19A ): Of walking type; coxa present; basis with one pinnate seta proximally; about as long as merus, carpus and half of propodus combined; ischium short, with one seta; merus as long as carpus with two distal setae; carpus with four short setae distally; propodus with three subdistal setae.

Pereopod-2 ( Fig. 19B ): Of walking type; coxa present; basis almost as long as merus, carpus and propodus combined; ischium with one seta ventrally; merus almost as long as carpus, with three setae distally; carpus with two simple, one bipinnate, and one spiniform seta; propodus 1.5 times as long as carpus; dorsal edge with two setae distally and one seta ventrally; unguis 1.5 times as long as dactylus.

Pereopod-3 ( Fig. 19C ): Similar to pereopod-2, but merus with two simple and one spiniform setae.

Pereopod-4 ( Fig. 19D ) Of clinging type; basis robust, about twice as long as wide; ischium with two setae ventrally (one shorter than other); carpus slightly longer than merus, each with two large hook-like setae; propodus as long as carpus, with two ventral spiniform setae, one terminal seta and one pinnate seta on dorsal edge; unguis trifurcated.

Pereopod-5 ( Fig. 19E ): Similar to pereopod-4.

Pereopod-6 ( Fig. 19F ): Similar to pereopod-4, but propodus with three dorso-distal setae.

Pleopods 1–5 ( Fig. 19G ): All pleopods similar; basal article naked; exopod and endopod each with proximal seta separated from the others by gap; exopod outer edge with nine plumose setae, inner edge with one pinnate seta; endopod armed with 17 plumose setae on outer edge.

Uropod ( Fig. 19H ): Both rami one-articled. Endopod with pinnate seta in the middle and one pinnate and four simple setae distally; exopod just as long as endopod, with one seta proximally, one robust seta and one simple seta terminally.

Male: Unknown.

Distribution: West Antarctic, north of South Shetland Islands, at depths of 2372–3876 m.

Remarks: Hamatipeda trapezoida n. sp. is distinguished from H. longa by the trapezoidal shape of pereonites 1–3 in contrast to H. longa in which the pereonite lateral edges are parallel. The other diagnostic feature is the length of the uropodal rami; the exopod of the uropod is subequal in H. trapezoida but it is clearly shorter than the endopod in H. longa .

Figures

FIGURE 17. Hamatipeda trapezoida n. sp. A) Paratype, dorsal view (Polarstern Sta. 41-3); B, C) Holotype, lateral view (Eltanin Cr 4 Sta. 129). Scale = 1 mm.

FIGURE 18. Hamatipeda trapezoida n. sp., female paratype. A) Antennule; B) Antenna; C) Left mandible; D) Right mandible; E) Maxillule; F) Maxilla; G) Labium; H) Maxilliped; I) Epignath; J) Cheliped. Scale: A, B, J = 0.1 mm; C-H = 0.01 mm.

FIGURE 19. Hamatipeda trapezoida n. sp., female paratype. A) Pereopod-1; B) Pereopod-2; C) Pereopod-3; D) Pereopod-4; E) Pereopod-5; F) Pereopod-6; G) Pleopod; H) Uropod. Scale = 0.1 mm.