Notopoma stoddartae, Lowry & Berents, 1996

Lowry, J. K. & Berents, Penelope B., 1996, The Ericthonius group, a new perpective on an old problem (Crustacea: Amphipoda: Corophioidea), Records of the Australian Museum 48 (1), pp. 75-109 : 99-103

Notopoma stoddartae n.sp.

Figs 16-18

Type data. HOLOTYPE, male, 2.74 mm, AM P40436; PARATYPE, male, 2.30 mm, AM P40437; PARATYPE, female, 2.15 mm, AM P40438; 49 PARATYPES, AM P40470; 20 PARATYPES, USNM 274136; outer reef edge near the wreck of the Runic, Middleton Reef, Tasman Sea , 29°27.4'S 159°03.7'E , rubble, algae, coarse sediment, 12 m, J.K. Lowry & R. T. Springthorpe, 5 December 1987, site 8.1; 30 PARATYPES, AM P40471, outer reef slope near the wreck of the Fuku Maru, Middleton Reef, Tasman Sea 29°29.1'S 159°08.1'E , coral rubble, 12 m, Australian Museum Party, 7 December 1987, site 20; 6 PARATYPES, BMNH 1995.716­ 721, outer slope west of the wreck of the Yoshin Maru Iwaki, Elizabeth Reef, Tasman Sea , 29°57.2'S 159°01.2'E .

Material described. Based on holotype male, 2.74 mm; dimorphic characters based on paratype female, 2.15 mm.

Diagnosis. Antennae: short, robust. Mandible: palp article 2 article 2 short, broad, length 1.6 x breadth, article 3 broad, clavate. Maxilla 1: outer plate with 9 setal-teeth. Gnathopod 2: male propodus broad, curved, length 3.2 x width. Peraeopod 7: dactylus with one accessory spine. Pleopod 2: uniramous. Pleopod 3: absent.

Description. Head: rostrum short, straight, apically rounded, length 0.37 x head; lateral cephalic lobe well developed, ventral corner rounded, subocular margin deeply recessed, anteroventral corner subquadrate, ventral margin horizontal, posterior margin vertical. Antenna 1: short, 0.3 x body length, without scales; peduncular article 1 produced dorsodistally and dorsomedially, dorsodistal projection 0.4 along article 2, length 1.2 x peduncular article 3; accessory flagellum absent; flagellum short, 2-articulate (female 2), aesthetascs absent, article 1 long, 2.1 x article 2. Antenna 2: subequal in length to antenna 1; peduncle without scales; flagellum 3­ articulate (female 3), article 1 long, 2.8 x article 2.

Epistome and upper lip: fused, produced, subacute. Mandible: left incisor with 4 cusps, right incisor with 4 cusps; left lacinia mobilis with 4 cusps, right with 2 large cusps and minutely serrate margin; left accessory setal row with 2 pappose robust setae, without intermediate plumose setae, right accessory setal row with 2 pappose robust setae, without intermediate plumose setae; molar triturating, molar flake on left and right side, molar seta absent; palp article 2 short, broad, length 1.6 x breadth, 0.9 x article 3, with 1 proximal and 1 distal A2-setae, 5 submarginal A2-setae, and 4 submarginal B2-setae; article 3 clavate, short, 2.3 x breadth, with 3 proximal A3-setae, 5 submarginal A3- and 5 submarginal B3-setae and 6 E3-setae. Maxilla 1: inner plate small, with 1 simple apical seta; outer plate with 9 setal-teeth; right and left palps each with 3 terminal., robust setae, flag seta present on distolateral corner, right and left palps each with 2 subterminal setae. Maxilla 2: outer plate broader than inner; inner plate with setae distally along medial margin. Maxilliped: inner plate subrectangular with 3 nodular robust setae, without subterminal robust setae on medial corner, oblique setal row with 7 plumose setae; outer plate with 2 apical plumose setae, and 4 apicomedial robust setae; palp article 2, length 2.1 x breadth, article 3, length 1.7 x breadth.

Peraeonite 5: male, length 1.8 x breadth, female, length 1.8 x breadth. Gnathopod 1: subchelate; coxa not fused to peraeonite 1 in male or female, length 1.5 x depth, with short anteroventral lobe; basis in male with sparse setae along anterior margin, in female with sparse setae along anterior margin, with robust setae along anterior margin; carpus length subequal x depth with setose posterior lobe, anterior margin without setae in male and female; propodus length 1.3 x depth, ·with 6 rows of anteromedial setae; palm acute, sparsely setose, with barbed robust setae. Gnathopod 2: carpochelate in male, subchelate in female; coxa not fused to peraeonite 2 in male or female, length 1.6 x depth, without anteroventral lobe; basis short, broad, length 1 x breadth; carpus massive, long, broad, length 1.1 x breadth, posterior margin without tooth; palm transverse, broadly excavate, anterodistal tooth large, located near articulation with propodus, posterodistal tooth well defined, medium in size, length 1 x width, without robust setae; propodus broad, curved, length 3.2 x width, without tooth on posterior margin, with rugose posterodistal corner; dactylus, length 0.4 x propodus.

Peraeopod 3: coxa not fused to peraeonite 3 in male or female, length 2.3 x depth, with small anteroventral lobe; basis length 1.1 x breadth, with inflated ·anterodorsal corner, without setal group, with denticles along anterior margin; ischium length 1.8 x breadth; merus without ridges; carpus with 1 simple seta along distal half of anterior margin, with 2 plumose setae along distal half- of posterior margin; propodus with 3 plumose setae along posterior margin. Peraeopod 4: coxa not fused to peraeonite 4 in male or female, length 2.4 x 摥灴桾 without anteroventral lobe; basis length 1.2 x breadth, without setal group along anterior. margin; ischium long, length 1.8 x breadth; carpus with 2 simple setae along distal half of anterior margin, with 1 plumose seta along distal half of posterior margin; propodus with 3 simple setae along posterior margin. Peraeopod 5: coxa, length 1.8 x depth, without patches of small setae; anterior lobe of merus not extending beyond anterior margin of carpus, posterior lobe with 2 plumose setae; propodus with 1 seta along posterior margin, dactylus short, uncinate with two accessory spines. Peraeopod 6: coxa without patch of small setae; basis without anterior setae, with small denticles along posterodistal margin; merus, length 1.7 x breadth, without small anterodistal lobe; carpus without anterodistal lobe, without posterodistal lobe, posterodistal corner bearing small setal bunch; propodus, anterodistal corner bearing large setal bunch; dactylus short, uncinate with two accessory spines. Peraeopod 7: coxa with posterodorsal lobe, without patch of small setae; basis without denticles along anteroproximal margin, with small denticles along posterodistal margin; merus, length 2.3 x breadth, without slllull unterooistal lobe, posterodistal corner bearing sll1ulI "etal hunch; carpus without anterodistal lobe, with slllull posterodistal lobe, anterodistal corner bearing small setal bunch; propodus posterodistal corner bearing small setal bunch, anterodistal corner bearing large setal bunch; dactylus short, uncinate with one accessory spine.

Oostegites: from gnathopod 2 to peraeopod 5. Gills: from peraeopod 3 to peraeopod 6.

Pleopods 1 to 3: pleopod 1 larger than 2, pleopod 3 absent. Pleopod 1: peduncle without patch of small setae, with 2 small distomedial hooks; rami subequal in length; inner ramus without patch of small setae, 4­ articulate; outer ramus, article 1 with straight medial margin, 5-articulate. Pleopod 2: peduncle without patch of small setae, without distomedial hooks; uniramous, ramus without patch of small setae. Uropod 1: biramous, peduncle with distoventral corona of cuticular teeth, length 1.1 x outer ramus, without distoventral spine; outer ramus with lateral row of denticles, with 2 medial setae, with large apical robust seta; inner ramus length 0.3 x outer ramus, without setae, with apical robust seta. Uropod 2: uniramous, peduncle length 1.7 x breadth, 1.3 x ramus; ramus small, with denticles and 1 apical robust seta. Uropod 3: uniramous, peduncle length 1.7 x breadth; ramus with 5 curved spines. Telson: length 0.5 x breadth, cleft to base, each lobe with 12 to 12 anteriorly directed spines in two rows.

Thbe. Composed of detritus and sand grains.

Etymology. This species is named in recognition of the contribution of Helen Stoddart to amphipod systematics.

Remarks. Notopoma stoddartae shows similarities to species with short antenna 1 and with short mandibular palp ( N. harfoota , N. opposita and N. stoora ). It is very similar to N. stoora , but N. stoora differs in the carpus of peraeopods 6 and 7 which is posterodistally lobate, the presence of pleopod 3, and it is brightly coloured. Notopoma opposita has well-developed posterodistal lobes on the carpus of peraeopods 6 and 7, and two accessory spines on the dactylus ofperaeopod 7. Notopoma harfoota has a very distinctive female first gnathopod which distinguishes it from other species in the genus.

Distribution. Elizabeth and Middleton Reefs, Tasman Sea in depths of 12 to 21 m.

Figures

Fig. 16. Notopoma stoddartae n.sp., lateral view, male holotype, 2.3 mm, AM P40436; dorsal view, female paratype, AM P40438; Middleton "Reef, Tasman Sea.

Fig. 18. Notopoma stoddartae n.sp., male holotype, 2.3 mm, AM P40436; gnathopod 1, peraeopod 5 plus dactylus from female paratype, AM P40438; Middleton Reef, Tasman Sea. Scales represent 0.1 mm.