Drummondia tridentata, Lowry & Stoddart, 2012

Lowry, J. K. & Stoddart, H. E., 2012, The Pachynidae fam. nov. (Crustacea: Amphipoda: Lysianassoidea) 3246, Zootaxa 3246 (1), pp. 1-69 : 16

Drummondia tridentata sp. nov.

( Figs 9 , 10 )

Type material. HOLOTYPE, male, 3.8 mm, MV J14616 , south of Point Hicks , Victoria, Australia, 38°17.70'S 149°11.30'E, 400 m, coarse sand, gravel and mud, epibenthic sled, 24 July 1986, M.F. Gomon et al., RV Franklin, stn SLOPE 40 . PARATYPE, male, 3.4 mm, MV J14769 , east of Eden , New South Wales, Australia, 37°7.30'S 150°20.20'E to 37°5.30'S 150°21.80'E, 520 m, grey coarse shell, epibenthic sled, 20 July 1986, G.C.B. Poore et al., RV Franklin, stn SLOPE 19 .

Etymology. The specific name refers to the three dorsal spines on pereonite 5.

Diagnostic description. Head lateral cephalic lobe large, broadly rounded; ventral margin subsigmoidal. Antenna 1 peduncular article 1 with posterodistal spine; accessory flagellum 2-articulate, article 1 short; flagellum with strong 1-field callynophore in male, [female not known]. Mandible lacinia mobilis a simple robust seta; left accessory setal row modified into lamina dentata, right accessory setal row present, not on raised setose ridge; molar absent; palp attached midway; palp article 2 broad, longer than article 3; article 3 with subparallel margins. Maxilla 1 outer plate with 10 setal-teeth in 7/3 arrangement, outer row setal-teeth with lateral and medial cusps; palp absent. Maxilliped inner plate small; outer plate large; palp 4-articulate, article 4 large. Gnathopod 1 chelate; ischium smaller than propodus, not swollen posteroproximally; carpus extremely compressed; propodus length about 2 × breadth, posterior margin well developed, palm with produced corner, corner of palm with complex robust seta; dactylus reaching to corner of palm. Gnathopod 2 palm minute, obtuse. Pereonite 4 without dorsal spines. Pereonite 5 with 3 acute dorsal spines. Pereopod 5 merus with weak posteroproximal shoulder. Pereopod 6 basis with posteroventral lobe weakly produced; merus as broad as long, with posteroproximal shoulder. Pereopod 7 basis subovate with posterior margin weakly dentate. Epimeron 3 posterior margin without projections, posteroventral corner broadly rounded. Uropod 3 biramous, inner ramus extending less than halfway along outer ramus. Telson shorter than broad, entire.

Remarks. Drummondia tridentata is the only species in the genus with a reduced number of setal-teeth on the outer plate of maxilla 1.

Distribution. Bass Strait, Australia; 400–520 m depth.

Figures

FIGURE 9. Drummondia tridentata sp. nov. Holotype male, 3.8 mm, MV J14616, off Point Hicks, Victoria, Australia. Scales represent 0.05 mm.

FIGURE 10. Drummondia tridentata sp. nov. Holotype male, 3.8 mm, MV J14616, off Point Hicks, Victoria, Australia. Scales represent 0.1 mm.