Paraleptognathia antarctica Guerrero-Kommritz 2004, new combination

Paraleptognathia antarctica (Vanhöffen, 1914) new combination (Figs 3, 4)

Synonymy: Paraleptognathia antarctica Sieg, 1986

Akanthophoreus antarcticus Sieg, 1986

Leptognathia antarctica Vanhöffen, 1914

Leptognathia diversa Sieg, 1983

Material examined: 18 individuals. ZMH K­40562 RV ”Meteor” St. 50, one neuter, ZMH K­40563 RV ”Meteor” St. 87, one juvenile male, ZMH K­40564 RV ”Meteor” St. 96, one juvenile male, ZMH K­40565 RV ”Polarstern, Polarfuchs” St. 15, one female, ZMH K­ 40566 RV ”Walther Herwig” St. 89, one female, ZMH K­40567 RV ”Walther Herwig” St. 96, one female, one juvenile male, ZMH K­40568 RV ”Walther Herwig” St. 120, one neuter, ZMH K­40569 RV ”Walther Herwig” St. 161, one female, ZMH K­40570, RV ”Polarstern” St. 21, two females (one dissected), ZMH K­40571 RV ”Polarstern” St. 140, two juvenile males, one neuter, ZMH K­40572 RV ”Polarstern” St. 145, two females, ZMH K­40573 RV ”Polarstern” St. 147, two females.

Diagnosis: Cheliped carpal shield well developed, dactylus with crenulation.

Description: non­ovigerous female. Body (Fig. 3a, b): long, about 6.5 times as long as wide. Body length 1.22 to 3.0 mm. Cephalothorax (Fig. 3a, b): about 1.3 times longer than wide, as long as pleon, tapering to antennule insertion. Pereon (Fig. 3a, b): pereonite 1 as long as pereonite 6, pereonite 5 longer than 6, pereonite 2 longer than 5 and subequal to 3 and 4. Pleon (Fig. 3a, b): pleonite 1 longest, pleonites 2 to 5 subequal.

Antennule (Fig. 3c): article 1 longest, with five short and one long simple lateral setae, article 2 as long as article 4, with one distal long simple seta; article 3 shortest with two short simple setae; article 4 with five terminal simple setae.

Antenna (Fig. 3e): article 1 short, semifused to cephalothorax, naked; article 2 as long as wide, with one short spiniform seta dorsally; article 3 with one dorsal simple seta; article 4 longest with two long simple terminal setae and three distal short setae; article 5 with one terminal simple seta; article 6 with three simple terminal setae.

Labrum (Fig. 4d): hood­like, with a row of setules at the lateral margins.

Mandible (Fig. 4c): well calcified, lacinia mobilis spiniform; pars molaris ventrally directed.

Maxillula (Fig. 4a): endite with four rows of setules ventrally, with three short, one pinnate and five simple terminal spiniform setae.

Maxilla (Fig. 4f): rectangular, naked.

Labium (Fig. 4e): composed of two triangular lobes with one short simple seta distally.

Maxilliped (Fig. 4g): endites have no special features.

Epignath (Fig. 4b): as long as Maxillula, naked.

Cheliped (Fig. 3f): basis shorter than carpus; merus with one ventral simple seta; carpus with two ventral simple setae, one dorsal seta, one tubercle near insertion of chela, carpal shield developed, not prominent; propodus twice as long as dactylus smooth, with two ventral and three dorsal setae, three teeth on cutting edge; dactylus with a row of tubercles dorsally, not well developed in all specimens.

Pereopod 1 (Fig. 3i): coxa naked; basis three times longer than wide, naked; ischium short with simple short seta; merus triangular, smooth, with one spiniform seta; carpus smooth, as long as merus, with two spiniform setae; propodus smooth with one terminal spine and a short spiniform seta; dactylus smooth; unguis sharp, as long as dactylus.

Pereopod 2 (Fig. 3j): as pereopod 1 except basis with one short simple and one setulose setae. Carpus longer than merus; propodus with one simple seta distally.

Pereopod 3 (Fig. 3k): as pereopod 2, except basis with only one short simple seta.

Pereopod 4 (Fig. 3l): basis three times as long as wide, with one setulose and one simple setae ventrally; ischium short, with one simple short seta; merus with two spiniform setae; carpus with two long and one short spiniform setae; propodus with three terminal spiniform setae; dactylus curved; unguis sharp, about as long as dactylus.

Pereopod 5 (Fig. 3m): as pereopod 4, except basis with only one simple seta.

Pereopod 6 (Fig. 3n): as pereopod 5.

Pleopods (Fig. 3h): basal article triangular, exopod with seven long simple setae; endopod with six long simple setae.

Uropods (Fig. 3g): exopod about 0,6 of length of first article of endopod, article 1 with one long simple seta; article 2 with two terminal setae; endopod article 1 with four distal short simple setae; article 2 with five terminal setae.

Ovigerous females body length 2.3 to 3.0 mm.

Juvenile male body length 1.5 to 1.8 mm. Antennule (Fig. 3d): article 1 as long as article 2, naked; article 2 with one short simple seta; article 3 with a long simple seta; article 4 shortest with one simple seta; article 5 with three terminal setae.

Mancas body length 0.9 to 1.1 mm.

Distribution: this species is found in East Antarctic waters from the Weddell Sea to the Ross Sea, around Elephant Island, South Orkney Islands, Antarctic Peninsula.

Remarks: the species Paraleptognathia antarctica Sieg, 1986 is the synonym of P. antarctica (Vanhöffen, 1914). No significant differences were found during the analysis of the material. The row of tubercles on the dorsal edge of the chelipeds dactylus is not well developed in all specimens. P. antarctica species is very similar to P. gracilis but the carpal shield of the cheliped of P. gracilis is not as well developed as in P. antarctica. Moreover P. gracilis occurs in the Arctic and P. antarcica in the Southern Ocean.