Tanzanapseudes nieli, Stępień, Anna & Błażewicz-Paszkowycz, Magdalena, 2009

Stępień, Anna & Błażewicz-Paszkowycz, Magdalena, 2009, Two new species of the genus Tanzanapseudes Băcescu, 1975 (Tanaidacea: Apseudomorpha: Tanzanapseudidae) from mid-west Australia, Zootaxa 2283, pp. 40-50 : 42-45

Tanzanapseudes nieli n. sp.

( Figures 1–3 )

Material examined: Holotype, premature female (with rudimentary oostegites) ( WAM C42777), NIN 7A, South of Tantabiddy, 21°54.724' S 113°57.105' E, dead coral head, depth 3 m, 8 June 2008; Paratypes, two juveniles ( WAM C42778, one dissected on slides WAM C42779), NIN 7B, same locality, small coral rubble on sand, depth 2– 3 m.

Etymology: The species is named in honour of Dr Niel Bruce, the Curator at Museum of Tropical Queensland.

Diagnosis: Pereonites 1–3 with two pairs of minute spines dorsally, pereonites 4–5 with one pair of minute spines dorsally and pereonites 3–5 with pair of setae dorsally; anterolateral spinose processes about four times as long as wide. Antennule article 1 with few setae; cheliped carpus distal margin smooth; chela robust (twice as long as wide); pereopods 1–3 propodus with three spiniform setae ventrally; pleotelson distal processes outer margin smooth.

Description: holotype, premature female with rudimentary oostegites: Body ( Fig. 1 ) 1.82 mm long, 1.4 times as long as wide. Rostrum and anterolateral processes spinose. Eyes with pigment. Carapace 35% of body length, with four spinose processes on each side. Pereon 50% of total body length; each pereonite with one lateral spinose process one each side. Pleon 15% of body length consisting of three pleonites and pleotelson fused together, with lateral spinose processes; distal processes with smooth outer margin.

Description of the appendages based on paratype (juvenile specimen) of body length 1.1 mm.

Antennule (Fig. 2A) basal article three times as long as wide, with four spines on inner and six on outer margin; article 2 as long as wide, with simple seta distally; article 3 about twice as long as wide; accessory flagellum one-articled, with two simple and one pinnate setae; main flagellum 2.3 times as long as accessory flagellum, of three fused articles, bearing one, two and one aesthetascs on each article respectively, and with four simple and one pinnate setae on article 3 distally.

Antenna (Fig. 2B) article 1 with lateral projection smooth; article 2 subequal to article 4 and little longer than article 3; article 3 with one pinnate seta; article 5 twice as long as article 4, with four simple and two pinnate setae. Flagellum with two articles, flagellum article 2 twice as long as article 1, with one subdistal pinnate and three terminal setae. Squama absent.

Mouth parts: Labrum (Fig. 2D) distally setose. Right mandible (Fig. 2C’) incisor with four denticles, setiferous lobe with five multifurcate setae. Left mandible (Fig. 2C) incisor with four denticles; lacinia mobilis well developed, with three denticles, setiferous lobe with two multifurcate setae. Molar process (Fig. 2C’’) with serrated denticles distally. Mandible palp not discovered. Maxillule (Fig. 2F) outer endite with two simple setae on outer margin, eight robust spiniform and two simple setae distally; inner endite with three plumose setae distally; palp (Fig. 2F’) with three terminal setae. Maxilla (Fig. 2E) outer lobe of movable endite with two setae subdistally and four setae distally, inner endite with serrated setae; outer lobe of fixed endite with three leaf-shaped setae and adjacent serrated setae; inner lobe with four setae along distal margin and row of setae subdistally. Maxilliped (Fig. 2H) basis 1.4 times as wide as long, with three plumose setae on inner margin and with short seta distally on outer margin; palp article 1 with long seta on inner margin; article 2 with few setae on inner margin and one robust spiniform seta on outer margin, articles 3 and 4 with numerous setae on inner and distal margins; article 4 with one strong seta on outer margin.

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

Cheliped (Fig. 2I) basis 1.3 times as long as wide, with minute spiniform seta ventrally; merus 0.6 times as wide as long, with long, plumose seta ventrally margin; carpus about twice as long as wide, with five setae on ventral margin and short seta distodorsally; chela more robust than carpus, with one short seta at middle and one near dactylus insertion; fixed finger inner margin with about five blunt spines and three setae proximally, some setae distally and ventrally; dactylus with three simple setae distally; inner margin with a few blunt spines and with short plumose setae; unguis half as long as dactylus. Exopod absent.

Pereopod 1 ( Fig. 3 A) basis about 1.5 times as long as wide, with two setae on ventral margin and one dorsally; ischium as long as carpus, naked; merus twice as long as wide, with one seta distoventrally and one short spiniform seta distodorsally; carpus with two setae ventrally, two spiniform setae and one simple seta distodorsally; propodus 3.5 times as long as wide, with three spiniform setae ventrally, one short simple and one plumose seta distodorsally; dactylus 0.4 times as long as propodus, with two small setae on dorsal margin; unguis subequal in length to dactylus. Exopod 3-articled, terminal article with two plumose setae.

Pereopod 2 ( Fig. 3 B) similar to pereopod 1, but basis 1.3 times as long as wide, with two ventral and two dorsal setae; merus apparently shorter that in pereopod 1; carpus with three plumose and one simple setae distodorsally; propodus with one simple and one pinnate setae mid-dorsally and two plumose setae distodorsally; dactylus with one seta dorsally.

Pereopod 3 ( Fig. 3 C) similar to pereopod 2, but basis about twice as long as wide, merus with short spiniform seta distodorsally, carpus with four short and one long setae distodorsally, dactylus naked.

Pereopod 4 ( Fig. 3 D) basis 1.6 times as long as wide; ischium subequal merus, with one seta; merus with one seta dorsally and one seta ventrally; carpus 1.5 as long as propodus, with three simple setae and one spiniform seta distally; propodus 2.5 times as long as wide, with two spiniform setae ventrally, two simple setae dorsally and two plumose setae distodorsally; dactylus and unguis equal in length.

Pereopod 5 ( Fig. 3 E) similar to pereopod 4, but basis with two simple setae ventrally, one minute spiniform and one pinnate seta dorsally; carpus with one spine distoventrally, and two setae distodorsally.

Pereopod 6 ( Fig. 3 F) similar to pereopod 5 propodus with one spiniform and four plumose setae distodorsally.

Pleopods ( Figs 3 G, G’) in three pairs, basis twice as long as wide, two to three setae on inner and one to two setae on outer margin; endopod little shorter than exopod, with 3–4 plumose setae; pleopods 1 and 2 exopod with eight setae on inner, distal and outer margin; pleopod 3 exopod with three setae only.

Uropod ( Fig. 3 H) basal article three times as long as wide, with three short setae distally; exopod with two articles, article 2 with three setae distally; endopod with four articles, article 1 with two pinnate setae, article 2 with two pinnate and one simple setae, article 3 with two simple, article 4 with two simple and two pinnate setae distally.

Distribution: The species is known only from the type locality – Ningaloo, mid-western Australia from 2–10 m depth.

Remarks: The holotype female and juvenile paratype do not differ morphologically except in number of ventral spines in pereopod 4–6 (three versus two). The holotype has the antennule broken off, so it cannot be confirmed if the articles of the flagellum are fully fused, as they are in the other members of the genus.

T. nieli n. sp. is one of two Tanzanapseudes with the pleotelson distal processes smooth only along the outer margin. The other species – T. langi , known from a single pre-adult female, has a less spinose first article of antennule than the new species.

Tanzanapseudes nieli differs from T. elegans and T. polynesiensis by the numbers of spiniform setae on the propodus of the pereopods, those two species having four ventral spiniform setae on pereopods from 1 to 2. Additionally the new species can be distinguished from T. polynesiensis by the smooth distal margin on the cheliped carpus and the smooth basis of pereopods 2–3. T. nieli n. sp. has well-developed, narrow (almost four times as long as wide) processes on each side of the rostrum and shares this character with T. longiseta and T. langi . These processes are robust (twice as long as wide) in T. polynesiensis and smooth in T. levis n. sp.

Figures

FIGURE 1. Tanzanapseudes nieli n. sp., neuter, body dorsally. Scale bar equals 0.1 mm.

FIGURE 3. Tanzanapseudes nieli n. sp., neuter, A) pereopod 1; B) pereopod 2; C) pereopod 3; D) pereopod 4; E) pereopod 5; F) pereopod 6; G – G’) pleopods; H) uropod. Scale bars equal 0.1 mm.