Cymadusa platys, Hughes, Lauren E. & Peart, Rachael A., 2013

Hughes, Lauren E. & Peart, Rachael A., 2013, New species and new records of Ampithoidae (Peracarida: Amphipoda) from Australian Waters, Zootaxa 3719 (1), pp. 1-102 : 59-64

Cymadusa platys sp. nov.

( Figs. 34–37 )

Type material. Holotype male, 23 mm, dissected, 4 slides, WAM C24925, inside of Table Top Island, Duke of Orleans Bay, Western Australia (33°55’S 122°35’E), 2–6.5 m, dredge, 20 April 1976; paratype female, 24 mm, dissected, 2 slides, WAM C24925, inside of Table Top Island, Duke of Orleans Bay, Western Australia, 2–6.5 m, dredge, 20 April 1976.

Type locality. Table Top Island, Duke of Orleans Bay, Western Australia (33°55’S 122°35’E).

Etymology. Platys , Greek, flat, alluding to the flattened first articles of the second antenna.

Diagnosis. Antenna 1 accessory flagellum 10-articulate. Antenna 2 article 4 subequal to article 5. Mandible accessory setal row with 7 setae (8 on left). Maxilla 1 inner plate with 1 plumose seta; outer plate palp slender, article 2 with 7 robust setae. Gnathopod 1 similar to gnathopod 2 size; coxa 1 larger than coxa 2; basis longer than coxa, posterior margin lined with slender setae, with single anterodistal lobe, rounded; ischium without lobe; propodus subovate, palm susbacute, convex, defined by rounded corner with 1 robust seta. Gnathopod 2 basis anterodistall lobe, large, rounded, extending to end of ischium, posterior margin with row of slender setae; ischium without anterior lobe; carpus subtriangular, 0.7 times propodus length, anterior margin with clusters of slender setae; propodus subovoid to subrectangular, length 1.8 times width, anterior margin with clusters of long slender setae, palm subacute, excavate, defined by subquadrate corner with 1 robust seta; dactylus subequal to palm length, apically subacute, tapering evenly, inner margin crenate. Telson trapezoidal, with lateral and oblique rows of setae.

Description of holotype. Head. Antenna 1 similar to antenna 2; article 1 length 1.1 times article 2; article 2 length 3.5 times article 3; article 3 length 4 times article 1; primary flagellum with 89 articles; accessory flagellum 10-articulate. Antenna 2 article 4 subequal to article 5; flagellum with 42 articles. Upper lip distally setose. Mandible accessory setal row with 7 setae (8 on left); palp 3-articulate; article 2 with 6 slender setae; article 3 length twice width. Lower lip with notch; medial lobes subequal to lateral lobes; mandibular lobes recurved, apically rounded. Maxilla 1 inner plate with 1 plumose seta; outer plate palp slender, article 2 with 7 robust setae. Maxilla 2 inner plate more narrow than outer plate. Maxilliped outer plate line with short robust setae.

Pereon. Coxae 1–4 longer than broad. Gnathopod 1 similar to gnathopod 2 size; coxa 1 larger than coxa 2, posteroventral margin with tuft of long slender setae; basis longer than coxa, posterior margin lined with slender setae, with single anterodistal lobe, rounded; ischium without lobe; merus posterodistal corner subacute; carpus subtriangular, length twice width, 0.8 times propodus length, anterior margin with clusters of slender setae; propodus subovate, length 1.9 times width, palm susbacute, convex, defined by rounded corner with 1 robust seta, palm length 0.5 times posterior margin; dactylus subequal to palm length, apically subacute, tapering evenly, inner margin crenate. Gnathopod 2 sexually dimorphic; coxa with posteroventral tuft of setae; basis subequal to coxa length, anteroventral lobe, large, rounded, extending to end of ischium, posterior margin with row of slender setae; ischium without anterior lobe; merus posterior corner subacute; carpus subtriangular, length 1.2 times width, 0.7 times propodus length, anterior margin with clusters of slender setae; propodus subovoid to subrectangular, length 1.8 times width, anterior margin with clusters of long slender setae, palm subacute, excavate, defined by subquadrate corner with 1 robust seta, palm length 0.4 times posterior margin; dactylus subequal to palm length, apically subacute, tapering evenly, inner margin crenate.

Pleon. Epimera 1–3 subquadrate, posterior margin straight, posterodistal corner rounded. Uropod 1 reaching to the end of uropod 2; peduncle length twice width, with large acute distoventral spine, with 6 robust setae, setal fringe extending the length of peduncle; inner ramus longer than outer ramus, with 13 marginal robust setae; outer ramus with 18 marginal robust setae. Uropod 2 peduncle with distoventral spine, with 1 robust seta; inner ramus longer than outer ramus, with 8 marginal robust setae; outer ramus with 12 marginal robust setae. Uropod 3 peduncle length 1.6 times width with 11 distal robust setae; inner ramus 0.7 times peduncle length with 3 lateral robust setae, 5 distal robust setae and 12 distal slender setae; outer ramus with 2 recurved setae, with 4 lateral robust setae and fringe of lateral slender setae. Telson trapezoidal, with small apical cusps, with lateral and oblique rows of setae.

Remarks. See remarks for C. hentyana sp. nov.

Distribution. Western Australia: Duke of Orleans Bay (current study).

Figures

FIGURE 34. Cymadusa platys sp. nov., holotype male, 23 mm, WAM C 24925; female, 24 mm, WAM C 52419, Duke of Orleans Bay, Western Australia.

FIGURE 35. Cymadusa platys sp. nov., holotype male, 23 mm, WAM C 24925, Duke of Orleans Bay, Western Australia scales 0.5 mm.

FIGURE 36. Cymadusa platys sp. nov., holotype male, 23 mm, WAM C 24925; female, 24 mm, WAM C 52419, Duke of Orleans Bay, Western Australia, scales 0.5 mm.

FIGURE 37. Cymadusa platys sp. nov., holotype male, 23 mm, WAM C 24925, Duke of Orleans Bay, Western Australia, scales 0.5 mm.