Taraxapseudes, Santos, Kátia Christol Dos & Hansknecht, Tom, 2007

Santos, Kátia Christol Dos & Hansknecht, Tom, 2007, Taraxapseudes n. gen., Taraxapseudes diversus (Lang, 1968) n. comb. and two new species of Atlantapseudes B cescu, 1978 (Tanaidacea: Apseudidae) from Brazil and Madagascar, with a key for the genus, Zootaxa 1639, pp. 23-39 : 24-26

Taraxapseudes n. gen.

Etymology, from the Greek taraxis – disorder, confusion, owing to the problematic taxonomy of the type species, that was first classified as an Apseudes Leach,1814 and then as an Atlantapseudes Băcescu, 1978

Gender is feminine

Place Station Latitude Longitude Depth (m) Date

Santos Basin 110 24° 33’ S 43° 43’ W 1034 0 1.04.2002

Santos Basin 334 24° 36’ S 44° 07’ W 649 0 1.04.2002

Santos Basin 0 19 27° 28’ S 46° 53’ W 788 14.04.2002

Santos Basin 0 59 26° 59’ S 46° 48’ W 211 17.04.2002 Campos Basin 0 75 22° 38’ S 40° 32’ W 359 0 7.03.2002 Campos Basin 112 22° 26’ S 40° 00’ W 970 11.10.2002 Campos Basin 178 22° 43’ S 40° 26’ W 870 15.10.2002 Campos Basin 183 22° 43’ S 40° 26’ W 890 15.10.2002 Campos Basin 0 23 22° 39’ S 40° 23’ W 800 - NE Madagascar ID MEB0009 SD38 MAJ-EBS-09 14° 22.13’ S 46° 23.21’ E 1988 16.03.2006 NE Madagascar ID MEB0010 SD38 MAJ-EBS-10 14° 20.24’ S 46° 19.22’ E 2300 19.03.2006 Type and only species Taraxapseudes diversus ( Lang, 1968) n. comb.

Diagnosis. Rostrum acute with paired lobes at base. Eye lobes without ommatidia, with strong eyespines. Body with cuticle strongly calcified and ornamented with shallow fossae, armored in appearance. Carapace with or without lateral apophysis. Antennule with accessory flagellum of 3 articles, with antennule peduncle of 4 articles, including common. Third antennal article longer and thinner than second. Antenna with squama present or absent; if present, with single terminal seta or appearing as a pseudosquama. Pereonites with lateral spines and hyposphenia. Cheliped with dorsodistal process on carpus. Pereopod one stronger than others with propodus ventral margin bearing few spines. Pereopod four without short, ventral propodal comb. Pereopods five and six with ventral propodal combs. Pleonites, very short with dorsolateral and lateral apophyses. Pleonites bearing hyposphenia. Pleopods thin, present in both sexes, biramus or uniramus with few (1–2) terminal seta. Pleotelson with terminal dorsal cusp-like process. Male chela stronger than that of female. Oostegites, lacking on chela and present on pereopods 1–4.

Material examined. Illustrations and description of Lang (1968) and several undescribed members from the Gulf of Mexico available to TJH.

Discussion. Taraxapseudes n. gen. is immediately recognizable by the condition of the cuticle being armored in appearance like that of agathotanaids (See Bird and Holdich, 1988). The pleonites are very short appearing like that of the Pugiodactylinae ( Guţu 1995) or that of metapseudids. The pleonites also bear dorsolateral paired processes in addition to the lateral spines. Pleopods have one to two setae on the rami and were reported by Lang (1968) to possess 2 terminal setae on the endopod and to sometimes lack one of the rami in some pleopods. The pleotelson also bears a dorsal cusp that is visible with close inspection. The eyespines are large and project obliquely forward and also downward and outward. The new genus differs from Atlantapseudes by 1) the presence of a chela with an exopod 2) a longer third article on the antennule peduncle compared to the second article 3) a longer propodus on pereopod 1 without spines in a fanlike arrangement 4) pereopods 5 and 6 with short ventral propodal combs 5) strong spines on the pereonites 6) pleonites with paired apophyses and reduced pleopods 7) pleotelson with dorsodistal cusp. These differ from Apseudes Leach, 1814 as defined by Guţu (2006) by having 1) a chela without oostegites 2) short pleonites and 3) an antenna with an accessory flagellum of less than 5 articles. No other apseudid genera known by the authors have the combined characters of the new genus. It is interesting that Lang (1968) did not want to assign his species to Apseudes and eloquently stated for this species “The final decision, however, as to whether a separation is justified must await an examination of the other species of the genus, as some authors in their description of species pass the characters mentioned over in silence”.

The new genus appears to represent a group of highly modified deep sea tanaids with cuticular thickening, a reduction of the antennal squama, lacking in one undescribed species (TJH) along with the shortening of the pleonites and reduction of the pleopods. The pereopod propodal spines of one Gulf species are also spinulate resembling that of Carpoapseudes serratospinosus Lang, 1968 . The male of another Gulf species has an enlarged propodus like that of a Calozodion Gardiner, 1973 with a tooth on the fixed finger. The genus has a described member from the Tasman Sea and members from the Gulf of Mexico (present study).

For Atlantapseudes , we have observed that the lateral spine-like apophysis on the carapace often has smaller setae, that are found near or on the process, and these setae will assist with the diagnosis of a species. Although other apseudids have pereopod 1 propodi with digging spines, the combination of a short propodus with the spines steadily increasing in length and grouped in a fanlike (radial) arrangement is diagnostic for the genus. Based on observations to date, all species of Atlantapseudes are components of the bathyal slope and deep sea benthos of several continents; the genus is now known from North America, Europe, South America, Africa, Australia and Asia.