Apseudes paragracilis Kudinova-Pasternak, 1975

Jóżwiak, Piotr & Błażewicz-Paszkowycz, Magdalena, 2007, Apseudomorpha (Malacostraca: Tanaidacea) of the ANDEEP III Antarctic Expedition, Zootaxa 1610, pp. 1-25 : 2-8

Apseudes paragracilis Kudinova-Pasternak, 1975

( Figs 1–3 )

Apseudes paragracilis: Kudinova-Pasternak (1975) : 195–200; Apseudes (Apseudes) paragracilis Sieg (1983) : 69.

Material examined: three females, one male, two mancas ( K 41406 ), ANTXXII/3, sta. PS67/153–7, 63º19.15'– 63º19.31'S, 64º36.94'– 64º37.18'W, 29 Mar 2005, depth 2092–2118 m; one female, one juv. male, ( K 41407 ), ANTXXII/3 sta. PS67/154–S, 62°31.47'– 62°31.36'S, 64°39.45'– 64°39.25'W, 30 Mar 2005, depth 3804–3808 m.

Diagnosis: Carapace 0.9 as long as wide. Rostrum small, pointed and bent downward. One small spine (on ocular lobe) followed by a small tubercle on each anterolateral margin of carapace. Pereonites with one lateral spine (excepting pereonites 1 and 2). Pleon about one-third as long as total body length. Cheliped with exopod; basis with a ventral spine. Pereopod-1 merus subequal to carpus, both twice as long as wide, propodus with five spiniform setae ventrally and three dorsodistally. Dactylus of pereopod-1 with a row of four well developed denticles ventrally.

Description of the female with rudimentary oostegites. Body ( Figs 1 A, B) 7.5 mm long, slender, 6.1 times as long as wide. Carapace 15% of body length, 0.9 times as wide as long, tapering proximally, with one small spine on ocular lobe followed by a small tubercle on each lateral margin. Pereonite-1 3.3 times as wide as long; pereonite-2 trapezoidal, twice as wide as long; pereonites 3 and 6 as long as wide; pereonites 4 and 5 1.25 times as long as wide; pereonites 3 to 6 with anterolateral spines. Pleon 35% of body length, as long as last four pereonites; pleotelson a little longer than last three pleonites.

Antennule ( Fig. 2 A) peduncle article-1 3.5 times as long as article-2, with one long seta on distoinner margin, two pinnate and two simple setae on outer margin, and some minute setae on both margins; peduncle article-2 with one pinnate and four simple setae distally; peduncle article-3 half as long as article-2, with two simple setae distally; outer flagellum of nine articles; articles 3 and 4 with pair of simple setae distally; articles 4, 6 and 9 with aesthetascs; article-9 very short, with four simple setae terminally. Inner flagellum of five articles; articles 1 and 3 with pair of simple setae distally; article-4 with one bipinnate and one simple setae distally; article-5 with two setae terminally.

Antenna ( Fig. 2 B) peduncle article-2 twice as long as wide, with one seta at midinner side and two minute setae distally; squama longer than articles 3 and 4 of peduncle, with six simple setae at the distal half; article- 3 very short, wider than long, with one minute seta distally; article-4 a little shorter than article-5; article-5 four times as long as article-3, with one pinnate and two minute setae on outer margin. Flagellum, a little shorter than the peduncle, consist of six articles; article-1 half as long as peduncle article-5, with simple seta exceeding following article; article-2 little longer than article-1, with two simple setae distally; article-4 with one short and one long seta (exceeding last article); article-5 with two simple setae distally; article-6 with four (three long and one short) simple setae terminally.

Mouthpart. Labrum not recovered. Left mandible ( Fig. 2 C) with long and thin molar process, having numerous minute setae distally. Palp 3-articled; article-1 as long as wide, with three simple setae; article-2 slender, four times as long as article-1, with row of serrated setae on distal half of inner margin; article-3 about half as long as article-2, with row of setae on inner margin increasing in length distally; incisor with six blunt denticles; lacinia mobilis with some denticles, similar in size to incisor; setal row of five bifurcate and two simple setae. Maxillule ( Fig. 2 D) outer endite tipped by eleven spiniform setae (one very short) and two simple, subdistal setae. Inner endite with five plumose setae distally; both endites with simple margin setae. Palp ( Fig. 2 E) with two articles, distal article with seven setae tipped by row of small denticles directed backward. Maxilla ( Fig. 2 F) outer lobe of movable endite with minute setae on outer margin; two long setae subdistally and five setae distally; inner lobe of movable endite with about twelve simple setae. Outer lobe of fixed endite with one plumose and three trifurcated setae. Inner lobe of fixed endite with three plumose setae distally and row of numerous plumose setae subdistally. Maxilliped ( Fig. 2 H) basis as long as wide, with two short, simple setae on second half of inner margin. Palp article-1 with one short distal seta on outer margin and one long seta (exceeding distal end of article-2) on inner margin; article-2 with numerous long and short, simple setae on inner margin and with a very long outer seta distally; article-3 with seven simple setae on inner margin; article-4 with seven simple setae distally. Endite ( Fig. 2 I) with a row of six simple, four multifurcate and two spiniform setae on distal margin; one simple seta subdistally; inner margin with a row of three simple setae and two coupling hooks.

Epignath ( Fig. 2 G) basal plate twice as long as wide, naked; terminal seta 0.6 times as long as basal plate, setose in distal half.

Cheliped ( Fig. 3 A) basis relatively narrow, shorter than carpus, with ventral spine and three short setae distoventrally; merus half as long as carpus, with four simple setae and one short spiniform seta distoventrally; carpus, 4.5 times longer than wide, with a row of seven long setae ventrally, one seta at middle and two setae subdistally; propodus about 2.6 times as long as wide, with four simple (two long and two short) and two serrated setae near dactylus insertion; fixed finger with row of short setae and small denticles on inner margin and with three simple setae ventrally; dactylus narrower and longer than fixed finger, with three small denticles on distal half of inner margin and four simple setae (two long and two short) on upper margin. Exopod of three articles, distal article with five plumose setae.

Pereopod-1 ( Fig. 3 B) basis, ischium and part of merus broken in dissected specimen, merus subequal in length to carpus, with one simple and two minute setae distoventrally and with six setae distodorsally; carpus 1.4 as long as propodus, with two spiniform setae and five simple setae ventrally and with ten setae and one spiniform seta dorsally; propodus little longer than wide, with five spiniform setae ventrally and three spiniform setae distodorsally, four and three simple setae are present on dorsal and ventral margins, respectively; dactylus with one minute seta dorsally and a row of four denticles ventrally; unguis 0.4 times as long as dactylus.

Pereopod-2 ( Fig. 3 C) basis as long as combined length of ischium, merus and carpus, with one minute seta ventrally and three long setae distoventrally; ischium with two simple setae; merus 0.6 times as long as carpus, with three simple setae ventrally and six simple setae distally (four long and two short); carpus with a row of simple setae on ventral margin and some simple setae distally (two exceeding propodus); propodus 0.8 times as long as carpus, with four simple setae and two short, spiniform setae ventrally and with some simple and one short serrated setae distally; dactylus slender as long as merus, with one minute seta dorsally; dactylus and unguis together as long as propodus.

Pereopod-3 ( Figs 3 D, D') basis as long as combined length of merus, carpus and propodus with one seta on midventral margin; ischium with one seta; merus about 0.3 as long as basis, with five simple setae ventrally (three long and two short); carpus with some simple setae distally and ventrally (see magnification); propodus 0.7 times as long as carpus, with some simple setae on both margins and one serrated small seta ventrodistally; dactylus 0.8 times as long as propodus, with one minute seta dorsally; unguis half as long as dactylus.

Pereopod-4 ( Fig. 3 E) basis as long as combined length of merus, carpus and propodus, with two and three minute setae dorsally and ventrally, respectively; ischium with two simple setae; merus 0.25 as long as basis, with two simple setae two spiniform distoventrally and one simple distodorsally. Carpus with one spiniform seta ventrally and about ten simple setae distally and subdistally. Propodus narrow, about half as long as carpus, with some simple setae on distal margin. Dactylus broken.

Pereopod-5 ( Fig. 3 F) coxa with short seta; basis as long as merus, carpus and propodus combined, with one pinnate seta ventrally and one simple seta distoventrally; ischium with three simple setae; merus about 0.3 as long as basis, with three simple setae ventrally and one simple seta dorsally; carpus 1.5 times as long as merus, with two simple setae ventrally and five simple setae distally; propodus almost as long as carpus, with two simple setae and row of short spines ventrally; dactylus broken.

Pereopod-6 ( Fig. 3 G) basis little shorter than merus, carpus and propodus combined, with three minute setae at middle; ischium with two simple setae ventrally; merus 0.25 as long as basis with five simple setae subdistally; carpus as long as ischium and merus combined, with simple setae along article; propodus 0.8 times as long as carpus, with one simple seta and a row of numerous short spines ventrally and one simple seta distally; dactylus equal in length to merus, with one short seta dorsally; unguis 0.8 times as long as dactylus.

Pleopods ( Fig. 3 H) biramous, in five pairs; basal article 1.4 times as long as inner ramus, with two plumose setae; outer ramus, slightly shorter than the inner one, with one plumose setae proximally and seven long, plumose setae, distally and subdistally; inner ramus with long proximally plumose seta and seven long, plumose setae distally and subdistally.

Uropod broken.

Distribution: The species has been noted once by Kudinova-Pasternak (1975) in the vicinity of Falkland Islands ( Scotia Arch) and is presently reported from Livingston Island ( Antarctic Peninsula); depth range: 1105–3808 m.

Remarks: The long pleon, over one-third as long as the total body length, distinguishes Apseudes paragracilis Kudinova-Pasternak, 1975 from most species of genus Apseudes . A. abyssalis BłaŻewicz-Paszkowycz & Larsen, 2004 , A. siegi Kudinova-Pasternak, 1985 , A. levis Kudinova-Pasternak, 1985 , A. rotundifrons Bacescu, 1981 , and A. vitjazi Kudinova-Pasternak, 1970 are the other five species with a long pleon as observed in A. paragracilis .

Of these five species— Apseudes abyssalis is most similar to A. paragracilis in general body form, although the former species has a lateral spine on carapace while the latter has small tubercle there. The well developed lateral spines on the pereonites from 3 to 6 of A. paragracilis distinguish this species from A. levis , which has naked pereonites in dorsal view. Furthermore A. levis has only four spiniform setae on the ventral margin of the propodus of pereopod-1 and it also has elongated pereonites from 4 to 6 in contrast to A. paragracilis . Elongated pereonites are also characteristic for A. siegi . The description and the drawings made by Kudinova-Pasternak (1985) are unclear; but on the maxilliped endite presented in figure 3 (page 690, op. cit.), there is a leaf-like seta which indicating that the species should be transferred to the subfamily Leviapseudinae .

Apseudes abyssalis Bła ż ewicz-Paszkowycz & Larsen, 2004

Apseudes abyssalis: BłaŻewicz-Paszkowycz & Larsen (2004) : 467, 484–497.

Studied material: five females, one male, ( K 41408 ), ANTXXII/3 sta. PS67/088–8, 68°3.66'– 68°3.61'S, 20°27.90'– 20°27.52'W, 27 Feb 2005, depth 4929–4931 m; one female, one male, ( K 41410 ), ANTXXII/3 sta. PS67/121–11, 63°37.73'– 63°37.55'S, 50°38.09'– 50°38.37'W, 15 Mar 2005, depth 2663– 2659 m; one female ( K41399 ), ANTXXII/3, sta. PS67/142–5, 62°11.21'– 62°11.24'S, 49°29.40– 49 °29.68'W, 18 Mar 2005, depth 3408– 3405 m.

Distribution: As far A. abyssalis was found out of Ross Sea and in the vicinity of the South Sandwich Islands ( BłaŻewicz-Paszkowycz & Larsen, 2004), in the eastern part of the Weddell Sea and south from South Orkney Islands (present study); at the depth range from 2659 to 4931 m.

Remarks: The specimens of Apseudes abyssalis were similar to the type specimens studied by Bla ż ewicz-Paszkowycz & Larsen (2004). Noteworthy are females found with fully developed oostegites that also have eight ventral spines on the propodus of pereopod-1, while preadult females usually have six spines there, as reported by the original authors.

Figures

FIGURE 1. Apseudes paragracilis. Female. A, Body dorsal view; B, Body lateral view. Scale line = 1 mm.

FIGURE 2. Apseudes paragracilis. Female. A, Antennule; B, Antenna; C, Left mandible; D, Maxillule; E, Palp of maxillule (last article); F, Maxilla; G, Epignath; H, Maxilliped; I, Maxillipedal endite. Scale line = 1 mm for A, B; 0.1 mm for C-I.

FIGURE 3. Apseudes paragracilis. Female. A, Cheliped; B, Pereopod- 1; C, Pereopod- 2; D, Pereopod- 3; D', magnification of carpus (distal part), propodus and dactylus of pereopod- 3; E, Pereopod- 4; F, Pereopod- 5; G, Pereopod- 6; H, Pleopod. Scale line = 1 mm.