Cymadusa jubata, 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 : 52-55

Cymadusa jubata sp. nov.

( Figs. 30 , 31 )

Type material. Holotype male, 15.0 mm, dissected, 4 slides, SAMA C7643, 20 km west southwest of Outer Harbour, Gulf St Vincent, South Australia (34°46’47.66”S 138°28’50.73”E), 24 April 1975, coll. J. McFarlane; paratypes 2 specimens (1 male and 1 female), SAMA C6658, 20 km west southwest of Outer Harbour, Gulf St Vincent, South Australia (34°46’47.66”S 138°28’50.73”E), 24 April 1975, coll. J. McFarlane.

Type locality. 20 km west southwest of Outer Harbour, Gulf St Vincent, South Australia (34°46’47.66”S 138°28’50.73”E).

Etymology. From jubata, Latin for maned, crested, in reference the distal hood on the propodus of male gnathopod 2.

Diagnosis. Mandible accessory setal row with 10 setae. Maxilla 1 inner plate with 6 slender setae; outer plate palp broad, article 2 with 10 robust setae. Gnathopod 1 coxa larger than coxa 2, anterior margin straight, anterodistal corner broadly rounded; basis shorter than coxa, anterodistal lobe, large, rounded, posterior margin with a few slender setae; ischium anterior lobe absent; propodus subrectangular, palm subacute, convex, defined by subquadrate corner with 1 robust seta, palm length 0.3 times posterior margin. Gnathopod 2 basis longer than coxa, anterodistal lobe rounded, reaching end of ishchium, posterior margin with cluster of short slender setae and a few long slender setae; ischium without anterior lobes; carpus subtriangular, 0.7 times propodus length, anterior margin with clusters of slender setae; propodus subrectangular, anterior margin with rows of slender setae, anterodistal corner produced into setose lobe, palm subacute, straight, defined by subacute corner with 1 robust seta, palm length 0.4 times posterior margin; dactylus subequal to palm, apically subacute, tapering evenly, inner margin crenate. Telson apical margin convex with lateral and oblique rows of setae.

Description of holotype. Head. Antenna 1–2 unknown. Mandible accessory setal row with 10 setae; palp 3- articulate, slender; article 2 with 6 slender setae; article 3 length 1.5 times width. Lower lip with slit; lateral lobes much longer than medial lobes, with single duct; mandibular lobes recurved, apically rounded. Maxilla 1 inner plate with 6 slender setae; outer plate palp broad, article 2 with 10 robust setae.

Pereon. Coxae 1–4 longer than broad. Gnathopod 1 smaller than gnathopod 2; coxa 1 larger than coxa 2, anterior margin straight, anterodistal corner broadly rounded; basis shorter than coxa, anterodistal lobe, large, rounded, posterior margin with a few slender setae; ischium anterior lobe absent; merus posterodistal corner subacute; carpus subtriangular, length 1.2 times width, 0.8 times propodus, anterior margin with a few slender setae; posterodistal corner produced subacute; propodus subrectangular, length twice width, anterior margin with a few slender setae, palm subacute, convex, defined by subquadrate corner with 1 robust seta, palm length 0.3 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 rounded, reaching end of ishchium, posterior margin with cluster of short slender setae and a few long slender setae; ischium without anterior lobes; merus posterodistal corners acute; carpus subtriangular, length 1.5 times width, 0.7 times propodus length, anterior margin with clusters of slender setae; propodus subrectangular, length 1.9 times width, anterior margin with rows of slender setae, anterodistal corner produced into setose lobe, palm subacute, straight, defined by subacute corner with 1 robust seta, palm length 0.4 times posterior margin; dactylus subequal to palm, apically subacute, tapering evenly, inner margin crenate.

Pleon. Epimeron 1 rounded, posterodistal margin convex, posterodistal corner broadly rounded. Epimera 2–3 subquadrate, posterodistal margin straight to weakly convex, posterodistal corner rounded. Uropod 1 reaching end of uropod 2 rami; peduncle length 3 times width, setal fringe along entire margin, with large distovental spine, with 12 robust setae; inner ramus longer than outer ramus with 7 marginal robust setae; outer ramus with 6 marginal robust setae. Uropod 2 peduncle with small distoventral spine, with 6 robust setae; inner ramus longer than outer ramus with 7 marginal robust setae; outer ramus with 5 marginal robust setae. Uropod 3 peduncle length 1.5 times width, with 8 distal slender setae; inner ramus 0.7 times peduncle length, subequal to outer ramus, with 1 lateral robust setae, 7 distal robust and 9 slender setae; outer ramus with 2 large recurved robust setae, 2 lateral robust setae, lateral slender setae and patch of denticles. Telson subtrapezoidal, apical margin convex, with small apical cusps, with lateral and oblique rows of setae.

Remarks. The produced anterodistal corner of the propodus of male gnathopod 2 having a setose lobe is seen in C. jubata sp. nov. and C. hentyana sp. nov. The subrectangular gnathopod 1 propodus with a subacute, convex palm distinguishes C. jubata sp. nov. from C. hentyana sp. nov., in which the propodus is subovate with an acute and weakly convex palm. See also remarks for C. hentyana sp. nov.

Distribution. South Australia: Gulf St Vincent (current study)

Figures

FIGURE 30. Cymadusa jubata sp. nov., holotype male, 15 mm, SAMA C 7643, Outer Harbour, Gulf St Vincent, South Australia.

FIGURE 31. Cymadusa jubata sp. nov., holotype male, 15 mm, SAMA C 7643, Outer Harbour, Gulf St Vincent, South Australia, scales 0.1 mm.