Galathella Barnard & Karaman 1987

Galathella Barnard & Karaman

Galathella Barnard & Karaman, 1987: 866.-Barnard & Karaman, 1991: 488.

Diagnosis. Head: lateral cephalic lobe apically rounded. Antenna 1: peduncular article 1 without posterodistal tooth; callynophore well developed in female and male, without posterodistal simple or robust setae. Upper lip/ epistome separate. Mandible: molar setose, with reduced distal triturating surface; mandibular palp with proximal A3-setae, with slender, blade-like article 3. Maxilla 2: outer plate longer than inner plate, without extremely elongate setae. Maxilliped: outer plate distomedially rounded. Gnathopod 1: simple to weakly subchelate; coxa slightly shorter than coxa 2, tapering distally; ischium long, carpus very long. Peraeopods 3 and 4: males without plumose setae on posterior margin of merus and carpus. Epimeron 3: posteroventrally produced. Telson: moderately to deeply cleft.

Type species. Schisturella galatheae Dahl, 1959, original designation.

Species composition. Galathella contains G. bassiana n.sp., G. galatheae (Dahl, 1959), G. latipes (Ledoyer, 1986) and G. palana n.sp.

Remarks. Of those genera with a tapering first coxa only Centromedon Sars, 1891 and Galathella have a 7/4 crown setal-tooth arrangement on the outer plate of maxilla 1. Centromedon differs from Galathella as follows: the lateral cephalic lobe is subacute; there is no callynophore in the female; the molar is less developed; the mandibular palp has no proximal A3- setae; and the posteroventral corner of epimeron 3 is produced into a large spine.

Similarities between the two genera are striking. The parallel development of gnathopod 1 within each genus is particularly noticeable. Each genus has species in which gnathopod 1 is simple with long carpus and propodus, weakly subchelate with the palm extremely acute, or strongly subchelate with nearly transverse pahns. Species of Centromedon are currently known from northern hemisphere Arctic and temperate regions and lower latitudes in abyssal depths. Species of Galathella are currently known from southern hemisphere tropical and temperate regions in shallow to abyssal depths.

Alllysianassoid species which have a 7/4 crown setaltooth arrangement, and for which the life style is known, spend at least part of their life history as scavengers or micropredators (e.g., Dahl, 1979; Sainte-Marie, 1984; Sainte-Marie & Lamarche, 1985; Lowry & Stoddart, 1992). It is therefore highly probable that species in Galathella are demersal scavengers and/or micropredators.

Distribution. Kermadec Trench (7000 m), south-eastern Australia (600 to 1850 m), south-western Pacific Ocean; lIes Glorieuses, western Indian Ocean (28 m).

Key to the species of Galathella

1. 2.

3. Maxilla 1 palp with short conate terminal setae; peraeopod 7, merus slightly expanded, margins subparallel................................................ G. galatheae

--Maxilla1palp with long conate terminal setae; peraeopod7, TODO TODO TODO merusexpanded expanded,posterior marginrounded............................................................... latipes