Cymadusa lumanus, 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 : 55-56

Cymadusa lumanus sp. nov.

( Figs. 32 , 33 )

Type material. Holotype male, 10 mm, dissected, 4 slides, MAGNT Cr017901, Skirmish Point area, Boucat Bay, east of Maningrida, Arnhem Land, Northern Territory, Australia (11°58’38”S 134°17’10”E), 1.2 m, sand with rocky outcrops, 2 December 2004, coll. S.K. Horner and G.M. Dally (SKH04/110); paratype female, dissected, 4 slides, MAGNT Cr017902, Skirmish Point area, Boucat Bay, east of Maningrida, Arnhem Land (11°58’38”S 134°17’10”E), 1.2 m, sand with rocky outcrops, 2 December 2004, coll. S.K. Horner and G.M. Dally (SKH04/110); paratypes 4 specimens, MAGNT Cr017903, Skirmish Point area, Boucat Bay, east of Maningrida, Arnhem Land (11°58’38”S 134°17’10”E), 1.2 m, sand with rocky outcrops, 2 December 2004, coll. S.K. Horner and G.M. Dally, (SKH04/110).

Type Locality. Skirmish Point area, Boucat Bay, east of Maningrida, Arnhem Land, Northern Territory, Australia (11°58’38”S 134°17’10”E).

Etymology. From a conjection of the Latin words’luma’ and ‘manus’ meaning thorn-hand (neuter gender), in reference to the subacute midpalmar tooth of gnathopod 2.

Diagnosis. Antenna 1 peduncle article 1 with 1 distal robust seta; accessory flagellum damaged. Antenna 2 article 4 length subequal to article 5. Mandible accessory setal row with 9 setae; Maxilla 1 inner plate with 6 plumose setae; outer plate palp slender, article 2 with 9 robust setae. Gnathopod 1 coxa larger than coxa 2, anterior margin straight, anteroventral margin broadly rounded; basis anterodistal corner weakly rounded; ischium without lobe; propodus subtriangular, palm subacute, convex, defined by rounded to subquadrate corner with 1 robust seta. Gnathopod 2 basis shorter than coxa, with single anterodistal lobe large, with single slender setae; ischium anterior margin without lobe; carpus compressed, cup-shaped, 0.5 times propodus length; propodus broad, subovoid, palm subacute, with midmedial recurved subacute tooth, defined by subacute tooth, subquadrate corner without robust setae, palm 0.3 times posterior margin; dactylus subequal to palm length, apically acute, tapering evenly, inner margin crenulate. Telson apically truncate, with 2 pairs of lateral slender setae and an oblique row of slender setae.

Description of holotype. Head. Antenna 1 similar to Antenna 2; article 1 subequal article 2 length, with 1 distal robust seta; article 3 length 0.25 times article 1; primary flagellum with 32 articles; accessory flagellum damaged. Antenna 2 article 4 length subequal to article 5, flagellum incomplete, with more than 26 articles. Mandible accessory setal row with 9 setae; palp slender, 3-articulate; article 2 with 1 slender seta; article 3 length 4.3 times width. Lower lip with notch, lateral lobes subequal to medial lobes, with apical ducts; mandibular lobes recurved, apically rounded. Maxilla 1 inner plate with 6 slender setae; outer plate palp slender, article 2 with 9 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 broadly rounded; basis as long as coxa, anterodistal corner weakly rounded; ischium without lobe; merus posteroventral corners acute; carpus subtriangular, length 2.1 times width, 0.9 times propodus length; propodus subtriangular, length 2.1 times width, palm subacute, convex, defined by rounded to subquadrate corner with 1 robust seta, palm length 0.4 times posterior margin; dactylus overreaching palm, apically subacute, tapering evenly, inner margin crenate. Gnathopod 2 sexually dimorphic; basis shorter than coxa, with single anterodistal lobe large, with single slender setae; ischium anterior margin without lobe; merus posterodistal corners subacute; carpus compressed, cup-shaped, length subequal to width, 0.5 times propodus length; propodus broad, subovoid, length 1.3 times width, palm subacute, with midmedial recurved subacute tooth, defined by subacute tooth, subquadrate corner without robust setae, palm 0.3 times posterior margin; dactylus subequal to palm length, apically acute, tapering evenly, inner margin crenulate.

Pleon. Epimera 1–3 subquadrate, posteroventral margin weakly convex, posterodistal corner rounded. Uropod 1 reaching end of uropod 2 rami; peduncle length 2.1 times width, distroventral spine large, apically acute, with 11 robust setae; inner ramus subequal to peduncle length, longer than outer ramus, with 11 marginal robust setae; outer ramus with 12 marginal robust setae. Uropod 2 peduncle with small anterodistal spine, with 7 robust setae; inner ramus slightly longer than outer ramus, with 11 marginal robust setae; outer ramus with 11 marginal robust setae. Uropod 3 peduncle length 1.4 times width, with 2 lateral and 6 distal robust setae; inner ramus length 2.0 times width, 0.7 times peduncle length, subequal to outer ramus, with 6 slender setae, with 2 lateral and 4 distal robust setae; outer ramus with 2 recurved distal robust setae, with 1 lateral robust and 3 lateral slender setae. Telson trapezoidal, apically truncate, small apical cusps, with 2 pairs of lateral slender setae, 2 pairs of lateral plumose setae and an oblique row of slender setae.

Remarks. Cymadusa lumanus sp. nov. is most similar to C. imbroglio and C. chalongana in the form of gnathopod 1 carpus, propodus and dactylus and the broad, subovoid propodus of gnathopod 2 with well-developed midmedial tooth. Cymadusa lumanus sp. nov. can be distinguished by the shape of the midmedial tooth, which is recurved and apically acute, rather than subquadrate and rounded in C. imbroglio and C. chalongana .

Distribution. Northern Territory: Arnhem Land (current study).

Figures

FIGURE 32. Cymadusa lumanus sp. nov., holotype male, 10 mm, MAGNT Cr 017901, Boucat Bay, Arnhem Land, Northern Territory.

FIGURE 33. Cymadusa lumanus sp. nov., holotype male, 10 mm, MAGNT Cr 017901, Boucat Bay, Arnhem Land, Northern Territory, scales 0.1 mm.