Cymadusa hadros, 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 : 39-41

Cymadusa hadros sp. nov.

( Figs. 20 , 21 )

Type material. Holotype male, 22 mm, dissected, 2 slides and parts in microvial, SAMA C6387, Cape Northumberland, South Australia (38°03’S 140°39’E), deep amongst algae, September 1976, coll. S.A. Shepherd.

Type locality. Cape Northumberland, South Australia (38°03’S 140°39’E).

Etymology. Hadros , a Greek word meaning well-developed, stout, large, great.

Diagnosis. Antenna 1 primary flagellum proximal flagellum articles expanded on ventral margin; accessory flagellum 7-articulate. Antenna 2 article 4 longer than article 5, flagellum with more than 14 articles. Mandible accessory setal row with 10 setae. Maxilla 1 inner plate with 6 slender setae; outer plate palp slender, article 2 without robust setae. Gnathopod 1 coxa 1 larger than coxa 2, anterior margin straight, anteroventral margin produced, broadly rounded; basis with single anterodistal lobe, large, rounded, without setae, not extending beyond ischium; ischium anterior margin biolobate; propodus palm acute, weakly convex to straight, defined by 1 robust seta, palm length 0.66 times posterior margin. Gnathopod 2 basis longer than coxa, anterodistal lobe large, with single slender setae; ischium anterior margin bilobate; carpus anterior margin with clusters of robust setae; propodus subrectangular, length 1.9 times width, palm near transverse, with subquadrate midmedial tooth, defined by subquadrate corner without robust setae, palm 0.25 times length posterior margin; dactylus subequal to palm length, apically subacute, proximally broad, inner margin smooth. Telson apically subacute with 4 pairs of lateral robust setae, lateral and oblique rows of slender setae.

Description of holotype. Head. Antenna 1 similar to antenna 2; article 1 length 1.1 times article 2 length; article 2 length 4 times article 3; article 3 length 0.27 times article 1; primary flagellum with 65 articles, proximal flagellum articles expanded on ventral margin; accessory flagellum 7-articulate. Antenna 2 article 4 longer than article 5, flagellum incomplete, with more than 14 articles. Mandible accessory setal row with 10 setae; palp slender, 3-articulate; article 2 with 5 slender setae; article 3 length 2.6 times width. Lower lip with slit, lateral lobes slightly longer than medial lobes; mandibular lobes recurved, apically subacute. Maxilla 1 inner plate with 6 slender setae; outer plate palp slender, article 2 without robust setae. Maxilla 2 inner plate as broad as outer plate. Maxillaped outer plate lined with short robust setae.

Pereon. Coxae 1–4 longer than broad. Gnathopod 1 smaller than gnathopod 2; coxa 1 larger than coxa 2, anterior margin straight, anteroventral margin produced, broadly rounded; basis as long as coxa, posterior margin with a few slender setae, with single anterodistal lobe, large, rounded, without setae, not extending beyond ischium; ischium anterior margin biolobate; merus posteroventral corners subacute; carpus subtriangular, length twice width, 0.9 times propodus length; propodus subtriangular, length twice width, palm acute, weakly convex to straight, defined by 1 robust seta, palm length 0.66 times posterior margin; dactylus subequal to palm length, apically subacute, tapering evenly, inner margin crenate. Gnathopod 2 sexually dimorphic; basis longer than coxa, anterodistal lobe large, with single slender setae; ischium anterior margin bilobate; merus posterodistal corner produced, subacute; carpus subtriangular, length 0.8 times width, 0.6 times propodus length, anterior margin with clusters of robust setae; propodus subrectangular, length 1.9 times width, palm near transverse, with subquadrate midmedial tooth, defined by subquadrate corner without robust setae, palm 0.25 times length posterior margin; dactylus subequal to palm length, apically subacute, proximally broad, inner margin smooth.

Pleon. Epimera 1–3 subquadrate, posteroventral corner subquadrate. Uropod 1 reaching end of uropod 2 rami; peduncle length 3.5 times width, distroventral spine large, apically acute, with 9 robust setae; inner ramus 0.9 times peduncle length, longer than outer ramus, with 9 marginal robust setae; outer ramus with 9 marginal robust setae. Uropod 2 peduncle without anterodistal spine, with 4 robust setae; inner ramus slightly longer than outer ramus, with 7 marginal robust setae; outer ramus with 4 marginal robust setae. Uropod 3 peduncle length 1.2 times width, with 7 distal robust setae; inner ramus 0.8 times peduncle length, subequal to outer ramus, with 8 slender setae, with 1 lateral and 6 distal robust setae; outer ramus with 2 recurved distal robust setae, with lateral slender setae.

Telson trapezoidal, apically subacute, small apical cusps, with 4 pair of lateral robust setae, lateral and oblique rows of slender setae.

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

Distribution. South Australia: Northumberland (current study).

Figures

FIGURE 20. Cymadusa hadros sp. nov., holotype male, 22 mm, SAMA C 6387, Cape Northumberland, South Australia.

FIGURE 21. Cymadusa hadros sp. nov., holotype male, 22 mm, SAMA C 6387, Cape Northumberland, South Australia, scales 1 mm gn 1 and 2, all other scales 0.1 mm.