Hemikalliapseudes sebastiani, Bochert, Ralf, 2012

Bochert, Ralf, 2012, Apseudomorph Tanaidacea from the continental shelf of Angola and Namibia with descriptions of three new species, Zootaxa 3583, pp. 31-50 : 39-44

Hemikalliapseudes sebastiani sp. nov.

Figs. 5–7

Type material. Holotype: adult male, 4.1 mm; partially dissected (St. 36: dredge sampling; 17°00.988´S; 11° 27.478É) [ ZMB 28050]; Paratypes: 10 males, 10 females, 10 ovigerous females (same data as holotype [ ZMB 28050].

Further material. 2 females, 1 ovigerous female (St. 8: grab sampling; 12°05.273´S, 13°42.047´E); 6 females, 4 ovigerous females, 3.6–5.1 mm (St. 6: grab sampling; 9°26.000´S, 12°59.974´E); 1 male 4.1 mm, 1 female (St. 1: dredge sampling; 7°14.090´S, 12°41.010´E); 2 males 3.5–5.9 mm, 7 females, 3 ovigerous females 4.3–5.9 mm (St. 3: dredge sampling; 7°49.947´S, 13°02.992´E); 2 females 3.5–3.7 mm, 1 ovigerous female 3.3 mm (St. 39: dredge sampling; 7°51.947´S, 12° 58.450É); 64 individuals (St. 36: dredge sampling; 17°00.988´S; 11° 27.478É).

Description of the male. Body ( Fig. 5 A) dorso-ventrally flattened, small (length of holotype 4.1 mm), slender, about 5 times as long as wide. Cephalothorax about as long as wide, without rostrum, naked, anteriorly pointed ocular lobes well developed, with visual elements. Pereonite 2 shortest, pereonites 1 to 6 respectively 0.46, 0.4, 0.53, 0.48, 0.53 and 0.45 times as long as wide, pereonites 3 to 6 with mid-ventral invagination, all pereonites with anterolateral setae, spiniform apophysis present at pereonites 2, 5 an 6 ( Fig. 5 B). Pleon with five short free pleonites, pleonite 1 tapering proximally, pleonite 5 longest, rounded proximally, all pleonites with plumose setae laterally and a row of five to ten plumose setae dorsal mid-laterally. Pleotelson short, with prominent process at uropod insertion, distally rounded, with small setae antero-laterally, antero-dorsally and proximally.

Antennule. ( Fig. 5 C) Peduncle article 1 elongate, setose; article 2 half as long as previous article, with several simple setae; article 3 half as long as article 2; accessory flagellum with three, and main flagellum with twelve articles, single aesthetascs distally on articles 5, 7 and 9.

Antenna. ( Fig. 5 E) Peduncle four-articled, peduncle first article with prominent inner apophysis, with one small seta, distal margin slightly serrate; second peduncle article as long as fourth article, with short squama bearing seven setae, with about nine long simple setae on inner margin; flagellum of eight articles.

Mouthparts. Mandibles ( Fig. 5 G, H) with three-articulated palp, articles 1 and 3 subequal, article 2 longest, article 1 with long setae on inner margin and distally, articles 2 and 3 with long setae antero-laterally and distally; pars incisiva of both mandibles with four denticles; setiferous lobe of the left mandible with five and of the right mandible with four bi-or three-furcate setae; lacina mobilis only on left mandible, with four denticles; pars molaris thick. Labium ( Fig. 5 F) finely setose, its terminal lobe (palp) marginally densely setose, distally truncate with three setae. Maxillule ( Fig. 5 I) inner lobe with four plumose setae distally, outer margin with small apophysis and setose; outer margin of outer lobe densely setose, with nine spines distally and single seta subterminally. Maxilla ( Fig. 5 J) outer lobe of movable endite with fine setae on outer margin, inner and outer lobes of movable endite with finely-denticulate setae; fixed endite with three trifurcate spines, simple and denticulate setae; fixed endite inner margin slightly denticulate, with row of about 20 setae. Maxilliped ( Fig. 5 K, L) basis robust; palp with four articles, with numerous long setae on inner margins; first article with seta on outer margin; second article longest, with row of eight long simple setae mid-ventrally, about 22 shorter simple setae antero-laterally and three setae distally; third article little longer than last one, with 14 simple setae anterolaterally and five setae distally; endite with three couplers, with eight plumose setae on inner side, with three curved, three simple setae and two long blunt spines distally. Epignath ( Fig. 5 M) large, with simple terminal spine.

Cheliped. ( Fig. 6 A) Robust and relatively short, without exopodite; basis short and wide, with two simple setae on ventral side; merus slender, only slightly shorter than basis, with distal apophysis, with few simple setae distally and row of ten setae subterminally; carpus short, compact, distal with single seta dorsal and ventral; propodus very large, nearly twice as long as wide, fixed finger with tooth-like apophysis, with many setae on inner margin, claw strong; dactylus strong, long, with one apophysis proximo-ventrally, unguis strong, stout.

Pereopod 1. ( Fig. 6 C) With exopodite; without spiniform coxa; basis broad, about twice as long as wide, with four simple setae on ventral margin; ischium short; merus robust, distally dilated, distally with single strong, long, acute dorsal and ventral spines, ventral margin with six setae; carpus shorter than merus, with eight simple setae and one long, acute spine dorsally and disto-dorsally, with five setae on ventral margin and two spines distally; propodus shorter than carpus, with four simple setae and two finely-serrated spines disto-dorsally, with five simple setae proximo-ventrally, with three spines alternating with three small setae antero-ventrally; dactylus blunt, without unguis, with distal brush of 24 long setae.

Pereopod 2. ( Fig. 6 E) Basis long, with single simple seta mid-ventrally and four setae distally; ischium short; merus robust, slightly shorter than carpus, with 13 simple setae and single strong spine on ventral margin; carpus rectangular, with 18 simple setae and three strong spines on ventral margin, with three long simple setae and single short, acute spine distally; propodus short, about half length of carpus, with five spines ventrally increasing in length towards distally, with row of four spines medio-distally and single, long, simple seta disto-dorsally, with small broom seta mid-dorsally; dactylus slender, very long, about as long as basis or merus and carpus together, unguis absent.

Pereopod 3. ( Fig. 6 F) Relatively similar to pereopod 2; basis with two broom setae proximo-dorsally; merus with about 20 setae on ventral margin; carpus with five spines on ventral margin and three spines medio-distally; propodus with six spines ventrally, dactylus slightly shorter, about as long as carpus and propodus together.

Pereopod 4. ( Fig. 6 G) Basis long, with three broom setae on the proximo-dorsal margin; merus short, with two pairs of blunt spines antero-ventrally; carpus long, about twice as long as wide, more or less rectangular, with six stout spines on ventral margin, with row of eight stout spines medio-ventrally; propodus slightly longer than merus, with heavy broom seta proximo-dorsally, with six spines ventrally, with three serrate setae distally and with row of eight short serrate setae; dactylus short and slender, about as long as merus, with three simple sensory setae terminally, unguis absent.

Pereopod 5. ( Fig. 6 H) Relatively similar to pereopod 4; basis and propodus with broom setae; merus with three stout spines on ventral margin; carpus with row of five stout spines antero-medio-ventrally; propodus with five pairs blunt spines, increasing in length on inner and outer margin antero-ventrally and one very long spine distodorsally; dactylus shorter than longest spines, with four sensory setae terminally, unguis absent.

Pereopod 6. ( Fig. 7 A) Basis with ventral and dorsal long plumose setae; merus about as long as propodus, with four long plumose setae dorsally and eight simple setae ventrally; carpus slightly longer than merus and propodus, with row of seven setae on ventral margin and five plumose setae dorsally; propodus with five long spines ventrally and two long spines distally, and row of about 19 ciliate setae sterno-distally; dactylus very small, with single short seta, unguis absent.

Pleopods. ( Fig. 7 B) Biramous; in five pairs; basal article short and thick, with four long plumose setae on outer margin; rami uniarticulate, with plumose setae; endopodite shorter and narrower than exopodite; exopodite finely setose, with prominent insertion and single stronger plumose setae mid-dorsally.

Uropods. ( Fig. 7 C) Biramous; basis exceeding distal tip of telson, with two simple setae distally; exopodite four-articled and endopodite with 17 articles.

Female. Similar to the male except for antennule, cheliped and pereopod 1; articles of peduncle of antennule ( Fig. 5 D) slightly shorter than those of male, peduncle article 1 with broom seta distally, main flagellum with nine articles; cheliped ( Fig. 6 B) merus with row of 32 simple setae disto-ventrally and with long stout spine terminally, carpus about as long as merus, distally diluted, with row of eleven setae on dorsal margin, two additional setae proximo-medially, and three simple setae distally, with row of eleven setae antero-medially and about 16 setae antero-ventrally; propodus shorter than carpus, with single seta mid-dorsally, with about 13 setae distally, with six setae on ventral margin and row of seven setae antero-medially, fixed finger of chela with 15 denticles and 12 simple setae along cutting edge, distal spine long and slender; dactylus long, robust, with three setae mid-dorsally, with five fine spines ventrally, unguis slender. Pereopod 1 ( Fig. 6 D) merus with row of eleven simple setae antero-ventrally and eight setae disto-ventrally; carpus disto-dorsally more dilated than in male, with row of about 15 simple setae disto-dorsally, with pair of stout spines disto-dorsally; propodus additionally with four short setae mid-dorsally and with row of eight short, acute, serrate spines antero-ventrally; dactylus with distal brush of 28 long setae.

Etymology: The new species is named after Sebastian Elzemann, son of the author.

Remarks. Only three species were known within this genus to date, all described from West Africa ( Drumm & Heard, 2011). Hemikalliapseudes makellus Bamber, 2003 was found off Angola at 230 m water depth at 6°10´S. Hemikalliapseudes hanstroemi Lang, 1956 is known from 40 m water depth off the Congo River at 6°10´S and Hemikalliapseudes vasileradui Gutu, 2006 is a species from Mauretania waters (North-West Africa).

Hemikalliapseudes sebastiani sp. nov. is immediately separated from H. makellus and H. vasileradui by its absence of a spiniform coxa and the presence of an exopodite on pereopod 1, the accessory flagellum of antennule has only two articles in these species and they are without the anteriorly pointed eye lobe of the new species. In H. makellus and H. vasileradui the telson is longer than wide, the male cheliped propodus is proportionately shorter and the female cheliped merus proportionately longer, and the rami of the pleopods are more slender than in H. sebastiani sp. nov.. H.

hanstroemi differs from the new species by following features: antero-lateral corners of pereonites 2-6 dentiform, telson longer than wide, accessory flagellum of antennule with seven articles, no visual elements, rostrum short with broad margins, maxilliped endite with six couplers and dissimilar length and shape of pereopods 4 to 6 dactylus.

Distribution. West Africa: Off Angola from 7°–17° S; 19–117 m water depth.

Figures

FIGURE 5. Hemikalliapseudes sebastiani sp. nov. male A, dorsal view (left antennule and left uropod not shown); B, lateral view; C, antennule male; D, antennule female; E, antenna; F, labium; G, right mandible; H, left mandible (palp not shown); I, maxillule; J, maxilla; K, maxilliped (endite not fully shown); L, maxilliped endite; M, epignath.

FIGURE 6. Hemikalliapseudes sebastiani sp. nov. A, cheliped male; B, cheliped female; C, pereopod 1 male; D, pereopod 1 female; E, pereopod 2 male; F, pereopod 3 male; G, pereopod 4 male; H, pereopod 5 male.

FIGURE 7. Hemikalliapseudes sebastiani sp. nov. male A, pereopod 6; B, pleopod 3; C, uropod.