Galathella palana, Lowry & Stoddart, 1995

Lowry, J. K. & Stoddart, H. E., 1995, New lysianassoid genera and species from south-eastern Australia (Crustacea: Amphipoda), Records of the Australian Museum 47 (1), pp. 7-25 : 17-21

Galathella palana n.sp.

Figs 7-9

Type material. HOLOTYPE, female, ovigerous (3 eggs), 4.6 mm, NMV 114771 and PARATYPE, female, 4.0 mm, AM P42288: off Freycinet Peninsula , Tasmania, Australia, 42°2.20'S 148°38.70'E, coarse shelly sand, 800 m, epibenthic sled, M.P. Gomon et al. on RV Franklin, 7 July 1986, Cruise CSIRO FR5/86, stn SLOPE 45. 4 PARATYPES, NMV J37602 , south of Point Hicks , Victoria, Australia, 38°16.40'S 149°27.60'E to 38°17.70'S 149°26.1O'E, coarse shell, biogenic sediment, 800 m, epibenthic s1ed, M.P. Gomon et al. on RV Franklin, 23 July 1986, Cruise CSIRO FR5/86, stn SLOPE 34. 3

PARATYPES, NMV 114613, south of Point Hicks , Victoria, Australia, 38°19.1O'S 149°14.30'E, coarse sand, 600 m, epibenthic sled, M.P. Gomon et al. on RV Franklin, 24 July 1986, Cruise CSIRO FR5/86, stn SLOPE 39. 5 PARATYPES, NMV J37603 and 5 PARATYPES, AM P42291: off Freycinet Peninsula , Tasmania, Australia, 42°0.20'S 148°37.70'E, coarse shelly sand, 720 m, epibenthic sled, M.P. Gomon et al. on RV Franklin, 27 July 1986, Cruise CSIRO FR5/86, stn SLOPE 46. 2 PARATYPES, NMV J37604 , 54 km east-south-east of Nowra , New South Wales, Australia, 34°52.72'S 151°15.05'E, mud, fine sand, fine shell, 996 m, epibenthic sled, G.C.B. Poore et al., 22 October 1988, stn SLOPE 53 .

Diagnosis. Maxilla 1 palp with long, conate setae. Gnathopod 1 simple. Telson deeply cleft.

Description. Based on holotype female, 4.6 mm; paratype male, 4.0 mm. Head and body: without setae. Head: slightly longer than deep, ventrally truncated with straight ventral margin, lateral cephalic lobe large, broad, strongly projecting, apically rounded; rostrum small; eyes apparently absent. Antenna 1: peduncular article 1 medium length, length 1.5 x breadth, with small midmedial swelling; peduncular article 2 short, about 0.2 x article 1; peduncular article 3 short, 0.1 x article 1; accessory flagellum long, 0.53 x primary flagellum, 3-articulate, article 1 long, 1.2 x article 2; flagellum 7-articulate (male 9), with weak 2-field callynophore in female (strong 2-field callynophore in male), without flagellar robust setae, calceoli absent in female (5 present in adult male). Antenna 2: slightly longer than antenna 1; peduncle without brush setae (weak brush setae in male), strongly geniculate between peduncular articles 3--4, article 3 long, 1 x article 4 (male strongly geniculate between peduncular articles 3- 4, article 3 long, 1 x article 4) peduncular articles 4 and 5 not enlarged in female or male; flagellum 8- articulate (male 14), calceoli absent in female (about 12 present in adult male).

Mouthpart bundle: subquadrate. Epistome and upper lip: separate, epistome straight, upper lip produced, apically rounded. Mandible: incisors symmetrical, large, with slightly convex margins; lacinia mobilis a long slender cuspidate peg; accessory setal row, left and right rows each with 3 short, slender, simple setae; intermediate setae absent; molar setose with reduced distal triturating surface; mandibular palp attached distally; article 1 short, length 1.2 x breadth; article 2 slender, length 5 x breadth, 1.9 x article 3, with 8 submarginal posterodistal A2-setae (male 9), without D2-setae; article 3 slender, blade-like, long, length 3.4 x breadth, with 1 proximal A3-seta (male 1), with 8 distal D3-setae (male 11) and 2 apical E3-setae. Maxilla 1: inner plate narrow, with 2 pappose setae; outer plate extremely narrow with 11 setal-teeth in 7/4 crown arrangement, STl to ST3 large, stout, weakly to multicuspidate, ST4 large, slender, 6-cuspidate, ST5 large, slender, 7-cuspidate, ST6 large, slender, 7-cuspidate, left and right ST7 symmetrical, displaced down medial face, elongate, slender, multicuspidate medially, STA large, slender, displaced from STB, 3-cuspidate, STB large, broad, 6- cuspidate, STC large, broad, multicuspidate, STD broad, multicuspidate; palp large, 2-articulate, with 3 long terminal robust setae, with 1 subterminal seta, robust flag seta present on distolateral corner, distomedial margin serrate. Maxilla 2: inner plate narrow, outer plate broader, inner plate length 0.52 x outer plate. Maxilliped: inner plate large, subrectangular, with 3 apical nodular setae, oblique setal row strong with 10 pappose setae; outer plate small, subovate, with many fine apical setae, with 2 apical robust setae, medial setae small, blunt, submarginal setae long, simple; palp large, 4-articulate, article 2 slender, length 3.1 x breadth, 1.5 x article 3, article 3 long, slender, length 2.7 x breadth, dactylus well-developed, with 3 subterminal setae, unguis present.

Gnathopod 1: simple; coxa large, slightly shorter than coxa 2, tapering distally, anterior margin slightly concave, anteroventral corner rounded, posterior margin distally angled towards anterior margin; basis long, slender, length 5 x breadth, anterior margin smooth, with simple setae; ischium long, length 1.8 x breadth; merus, posterior margin with a few simple setae; carpus subrectangular, very long, length 5.1 x breadth, longer than (1.7 x) propodus, with patch of very fine setae near posterior margin and long simple setae along posterior margin; propodus large, subrectangular, length 2.8 x breadth, tapering distally, posterior margin smooth, straight, with 1 simple robust seta and simple, slender setae, palm absent; dactylus simple, with subterminal spine. Gnathopod 2: minutely subchelate; coxa large, subequal in size to coxa 3; ischium long, length 2.9 x breadth; carpus long, length 3.2 x breadth, posterior margin broadly lobate; propodus subrectangular, long, length 2 x breadth, palm transverse, with straight, serrate margin, posterodistal corner with 1 medial robust seta; dactylus reaching corner of palm, posterior margin smooth.

Peraeopod 3: coxa large; merus weakly expanded anteriorly; merus-carpus without plumose setae in male and female; propodus with 2 robust setae along posterior margin, with 2 distal locking setae; dactylus short, slender. Peraeopod 4: coxa deeper than wide, with weak posteroventral lobe, anterior margin slightly rounded, posterior margin slightly sloping anteriorly; merus weakly expanded anteriorly; merus-carpus without plumose setae in male and female; propodus with 3 robust setae along posterior margin, with 2 distal locking setae; dactylus short, slender. Peraeopod 5: coxa equilobate; basis expanded with posterior margin minutely crenate; merus expanded with rounded posterior margin; propodus with 2 robust setae along anterior margin, with 2 distal locking setae; dactylus short, slender. Peraeopod 6: coxa small, slightly lobate posteriorly; basis expanded posteriorly with minutely crenate posterior margin; merus expanded with rounded posterior margin; propodus with 3 robust setae along anterior margin, with 2 distal locking setae; dactylus short, stocky. Peraeopod 7: basis expanded posteriorly, posterior margin slightly rounded, minutely crenate, posteroventral corner rounded, posteroventral margin rounded; merus slightly expanded posterodistally with 3 robust setae; propodus malformed on holotype, paratype with 4 robust setae on anterior margin, with 2 distal locking setae, without setae along posterior margin; dactylus short, stocky.

Oostegites: from gnathopod 2 to peraeopod 5. Gills: from gnathopod 2 to peraeopod 7, not pleated.

Pleonites 1 to 3: pleonite 3 truncated dorsodistally. Epimeron 1: anteroventral corner broadly rounded. Epimeron 3: posteroventral corner produced, narrowly rounded. Urosomites: dorsally smooth; urosomite 3 with 1 small dorsolateral seta. Uropod 1: without fine setae; peduncle with 5 dorsolateral, 1 apicolateral, 3 dorsomedial and 2 apicomedial robust setae; outer ramus slightly shorter than inner ramus; outer ramus with 2 dorsal robust setae, inner ramus with 2 dorsal robust setae. Uropod 2: without fine setae; peduncle with 3 dorsolateral, 1 apicolateral, 1 dorsomedial and 1 apicomedial robust setae; outer ramus slightly shorter than inner ramus; outer ramus with 3 lateral robust setae; inner ramus with 2 lateral and 1 medial robust setae; inner ramus without constriction. Uropod 3: peduncle short, length 1.6 x breadth, without dorsolateral flange, with 1 apicolateral and 2 apicomedial robust setae, without midlateral slender or robust setae, with 3 distoventral robust setae, with 2 simple setae; rami lanceolate, inner ramus shorter than (about 0.88x) outer ramus; outer ramus 2- articulate, article 2 short, article 1 with 4 lateral and 1 medial robust setae (male with 1 lateral, 3 medial); inner ramus with 2 lateral robust setae (male with 3 lateral); slender plumose setae absent in female (present in male). Telson : longer than broad, length 1.5 x breadth, deeply cleft (87%), with 1 dorsal robust seta on each lobe, without dorsal slender setae distal margins incised, with 1 marginal 灥湩捩汬慴縠 seta on each lobe, without marginal simple setae, with 1 marginal robust seta on each lobe.

Etymology. Named for the village of Palana on Flinders Island, Bass Strait.

Remarks. Galathella palana differs from other species in the genus in having a simple gnathopod 1. In addition it differs from G. bassiana in having a deeply cleft telson .

Distribution. Galathella palana occurs on the continental slope off south-eastern Australia in 600 to 1000 m depth.