Paraleptognathia Kudinova­Pasternak, 1981

Guerrero-Kommritz, Jürgen, 2004, A revision of the genus Paraleptognathia Kudinova-Pasternak, 1981 (Crustacea: Tanaidacea) and description of four new species, Zootaxa 481 (1), pp. 1-63 : 8-10

Genus Paraleptognathia Kudinova­Pasternak, 1981

Synonymy: Akanthophoreus Sieg, 1986

Diagnosis: antennule with four articles, antenna with six articles, cheliped insertion via sclerite. Exopod of uropod composed of two articles. Merus of pereopod 1 with one spiniform seta and carpus with two spiniform setae. Ventral surface of cephalothorax with a groove around cheliped insertion.

Description: body long and slender, six to ten times as long as wide. Cephalothorax oval; no ocular processes; eyes absent. Pereon composed of six free pereonites. Pleon composed of five free pleonites and pleotelson; as wide as pereon and cephalothorax. Antennule of four articles in females and neuters, of five in juvenile males and seven in adult males. Antenna composed of six articles; article 1 short, semi­fused to cephalothorax; article 2 and 3 with a seta; article 4 longest with one or two distal setae. Labium hood­shaped with distal setules. Mandibles well calcified; molar process not pointed, with about ten end spinules. Lacinia mobilis thorn­like (cylindrical or flat with distal denticules). Maxillula endite with eight to ten terminal spiniform setae, some of them pinnate; palp with two terminal filaments. Epignath cudgel­shaped with one thin spine distally. Maxilla rectangular. Labium composed of two triangular lobes with some distal setae. Maxilliped basis fused, with two setae near insertion of palpus. Palpus composed of four articles, article 1 naked; article 2 with three inner and one outer setae; article 3 with three inner setae; article 4 with five terminal setae. Ventral surface of cephalothorax with a groove around cheliped insertion. Cheliped attached via sclerite. Cheliped merus with ventral simple setae; carpus with one dorsal seta near insertion of chela and sometimes near insertion to merus; one or two ventral simple setae at midlength; propodus with three dorsal simple short setae near cutting edge. Cutting edge with none to four teeth; fixed finger with two ventral long simple setae. Merus of pereopod 1 with one spiniform seta and carpus with two spiniform setae. Dactylus of pereopod 1–3 smooth and pointed. Dactylus of pereopod 4–6 bear a ventral groove bordered by spinules. Merus of pereopod 5 and 6 with two spiniform setae. Pleopod biramous; exopod with one long feathered seta. Uropod biarticled; exopod and endopod composed of two articles; exopod shorter then first article of endopod.

Ovigerous females: as non­ovigerous females, body flattened dorsoventrally with marsupium, composed of four oostegites originated at pereopod 1 to 4.

Neuter: as non­ovigerous female.

Juvenile males: as non­ovigerous females except antennule with five articles and cheliped ornamentation (crenulation, tubercles) more prominent.

Males: antennule with seven articles. Inner margin of chela with a row of simple setae near insertion of dactylus. Pleopods well developed, pleon almost as long as pereon.

Type species: Paraleptognathia typica Kudinova­Pasternak, 1981 , original designation.

Included species: in addition to the type species are: Paraleptognathia alba ( Hansen, 1913) , P. antarctica ( Vanhöffen, 1914) , P. australis ( Beddard, 1886) , P. bacescui Kudinova­Pasternak, 1985 , P. benguela n. sp., P. bisetulosa Dojiri & Sieg, 1997 , P. brachiata ( Hansen, 1913) , P.fastuosa n. sp., P. gracilis (Krøyer, 1842) , P.inermis ( Hansen, 1913) , P. longiremis (Lilljeborg, 1864) , P. multiserrata ( Hansen, 1913) , P. multiserratoides n. sp., P. tenuichela n. sp., P. weddellensis (Sieg, 1986) .

Remarks: the revision of the genus Paraleptognathia became necessary due to an observation made during the analysis of more than two thousand Tanaidacea from Greenland in 2003. Up to now Akanthophoreus and Paraleptognathia were recognized as valid genera. It was suspicious that in the studied material an undescribed species of Paraleptognathia was always found together with ” Akanthophoreus gracilis ”. Both species were very similar, sharing the same identification characters; the only difference was the five articles in antennule, and better expressed crenulation of cheliped and bigger tubercles in Paraleptognathia than in Akanthophoreus . Previous studies were bringing suspicious results: ovigerous females and mancas of Paraleptognathia were always absent in samples, although this species was sometimes very abundant, these findings were never explained. Further observation displayed that one non­ovigerous female of the new ” Paraleptognathia ” species from Greenland had a small genital cone. Hansen (1913) mentioned that the preparatory males of Leptognathia hanseni Vanhöffen, 1907 had five segments on the antennule. These facts led to a more detailed comparison of the two genera. After examining a male of ” Akanthophoreus gracilis ” and comparing it with the new Paraleptognathia species it was clear that this ” Paraleptognathia ” is a preparatory male of Akanthophoreus gracilis . This assumption led to the comparison of the rest of ” Akanthophoreus ” and ” Paraleptognathia ” species, Paraleptognathia antarctica and Akanthophoreus antarcticus , were sympatric and shared the same diagnostic characters. In samples with A. weddellensis or A. australis were always Paraleptognathia specimens that differs only in the number of articles in the antennule. After all these observations it has become clear that the genera Paraleptognathia and Akanthophoreus were synonyms. The discovery of unpublished notes of Jürgen Sieg deposited in the Zoological Museum Berlin (collection of Dr. O. Coleman) confirmed this observation.

Paraleptognathia was described by Kudinova­Pasternak in 1981 and has priority over Akanthophoreus Sieg, 1986 . Therefore Akanthophoreus is a junior synonym of Paraleptognathia .