Fluviadulzura spinicauda, Myers, Alan A., Lowry, James K. & Billingham, Zac, 2017

Myers, Alan A., Lowry, James K. & Billingham, Zac, 2017, A new genus and species of freshwater Hadziidae, Fluviadulzura spinicauda gen. nov., sp. nov. from rivers in Victoria, Australia (Amphipoda), Zootaxa 4232 (1), pp. 131-136 : 133-135

Fluviadulzura spinicauda gen. nov. sp. nov.

( Figs 1–4 )

Type material. HOLOTYPE male, 5.3 mm., Victoria, Woodford, Merri River at Bridge Road , 38.317388°, 142.482296°), 25/10/2015 ( NHMUK 2016 . 70).

Paratypes, 1 male, 2 females, same data as holotype ( NHMUK 2016 . 71- 73).

Other material. 4 males, 4 females, Victoria, Woodford, Merri River at Bridge Road , 38.317388°, 142.482296°, 29/04/2016 NHMUK 2016 . 74 – 81).

Type locality. Victoria, Woodford, Merri River at Bridge Road , 38.317388°, 142.482296°.

Etymology. Referring to the spine on the dorsum of the first urosome segment.

Description. Based on male holotype, 5.3 mm.

Head. Eyes moderately large, round; anteroventral corner rounded. Antenna 1 longer than antenna 2; peduncular article 1 shorter than article 2, with 2 robust setae on posterior margin; peduncular article 2 much longer than article 3; articles 1–3 with dense long setae; flagellum longer than peduncle with 22 articles; accessory flagellum well developed, with 4 articles. Antenna 2 moderately setose; peduncular article 2 cone gland reaching to end of peduncular article 3; peduncular article 4 slightly shorter than article 5; flagellum with 8 articles. Mandible molar medium size, triturating, accessory setal row present, 3 well developed serrate setae; palp very weak, 3- articulate; article 1 shorter than article 2; article 2 a little shorter than article 3; article 3 rod-shaped, lacking marginal setae but with two distal setae. Maxilla 1 inner plate subsquare, with 5 long, stout distal setae. Maxilla 2 inner plate without oblique setal row. Labium inner lobes absent. Maxilliped palp article 3, with distal patch of small dense setae; article 4 + dactylus forming stout claw.

Pereon. Gills huge, stalked. Gnathopod 1 subchelate; coxa anteroventral corner not produced, anterior margin straight, not produced; basis stout, broadest medially; carpus nearly 4 x as long as broad, much longer than propodus, heavily setose laterally; propodus palm weakly defined; dactylus well developed, reaching along half length of propodus posterior margin. Gnathopod 2 subchelate, enlarged; coxa posteroventral corner notch absent; merus acutely produced distoventrally; carpus short, not lobate, not enclosed by merus and propodus; propodus subovoid, nearly 3 x length of carpus, palm evenly rounded; dactylus closing along inner face of propodus. Pereopod 3–4 coxa subequal in length to coxa 2; dactylus short, substraight. Pereopod 4 coxa posteroventral lobe absent, posterior margin weakly concave. Pereopod 5 basis expanded, posterior margin weakly convex, posteroventral corner produced, subquadrate; carpus and propodus with few slender setae along anterior margin. Pereopod 6 basis posterior margin substraight, castelloserrate, posterodistal corner produced into a blunt spine; carpus and propodus with few moderate length, slender setae along anterior margin. Pereopod 7 coxa posterior lobe with two spines; basis posterior margin convex, minutely castelloserrate, scarcely produced posterodistally.

Pleon. Urosomite 1 with dorsal spine. Epimera 1–2 posteroventral margin with spine above posteroventral corner. Epimeron 3 ventral margin smooth, posteroventral corner with small acute spine. Uropod 1 peduncle with basofacial robust seta, without distoventral spine; rami subequal. Uropod 2 peduncle a little shorter than rami; rami slender, subequal. Uropod 3 inner ramus very short, blunt, with one subdistal seta about 0.1× outer ramus; outer ramus very long, much longer than peduncle, 2-articulate; article 2 spine-like. Telson cleft, about as broad as long, each lobe tapering distally, apical margins straight to weakly concave, with 3 apical and 2 subapical robust setae.

Female (sexually dimorphic characters). Based on female, 5.5 mm, Gnathopod 2 carpus subtriangular, 0.6 × length of propodus; propodus parallel-sided, palm oblique, delimited from posterior margin; dactylus fitting palm.

Habitat. Fluviadulzura spinicauda gen. nov. sp. nov. is known only from the type locality on the Merri river in south-western Victoria. This section of the Merri river is a lowland freshwater stream with large deep pools and small shallow riffles, abundant aquatic vegetation and predominantly gravel and pebble substrates.

Remarks. See remarks under genus.

Figures

FIGURE 1. Fluviadulzura spinicauda gen. nov. sp. nov., male paratype, Merri River.