Paragrubia dwyeri, 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 : 82-86

Paragrubia dwyeri sp. nov.

( Figs. 52–54 )

Type material. Holotype male, 11.5 mm, dissected, 4 slides, AM P.90117, Smiths Point, Christmas Island, Indian Ocean (10°26’02”S 105°39’38”E), 5 m, mooring can and chain, 20 October 2008, coll. J.K. Lowry and L.E. Hughes (MI WA 896); Paratypes 10+ specimens, AM P.81800, Smiths Point, Christmas Island, Indian Ocean (10°26’02”S 105°39’38”E), 5 m, mooring can and chain, 20 October 2008, coll. J.K. Lowry and L.E. Hughes (MI WA 896).

Additional material examined. Western Australia: Male, 15.1 mm, dissected, 4 slides, WAM C45858, Cassini Island, The Kimberley (13°56’28”S 125°37’23”E), 2 m, 17 October 2010, coll. Skipton Wooley (35/K10- T4, Woodside Kimberley Survey 2010); many specimens, WAM C45858, Cassini Island, The Kimberley (13°56’28”S 125°37’23”E), 2 m, 17 October 2010, coll. Skipton Wooley (35/K10-T4, Woodside Kimberley Survey 2010).

Type locality. Smiths Point, Christmas Island, Indian Ocean (10°26’02”S 105°39’38”E).

Etymology. Named for Darrell Dwyer, the skipper of the MV Fastwater at Christmas Island.

Diagnosis. Antenna 1 accessory flagellum 7-articulate. Mandible accessory setal row with 7 robust setae. Lower lip outer plates weakly notched; lateral lobes subequal to medial lobes, without apical ducts, mandibular lobes with curved margins, subacute apically. Maxilla 1 outer plate palp slender, article 2 with 4 robust setae. Gnathopod 1 larger and stouter than gnathopod 2; coxa 1 smaller than coxa 2, anterior margin straight, anteroventral corner weakly produced, subacute; basis longer than coxa, posterior margin with clusters of sparse slender setae, with single anterodistal lobe large, rounded, with 3 slender setae; ischium anterior margin with small lobe; propodus subovoid to subrectangular, broad, palm subacute, deeply excavate, defined by subquadrate corner with 1 robust seta. Gnathopod 2 basis longer than coxa, with single anterodistal lobe large, rounded, not reaching beyond ischium, anterodistal corner with 3 slender setae; ischium anterior margin without lobe; propodus subrectangular, length 1.9 times width, palm subacute, concave, defined by subquadrate corner with 1 robust seta. Telson subovoid, apically rounded, 5 pair of lateral setae and 2 rows of oblique medial setae.

Description of holotype. Head. Antenna 1 similar to antenna 2; article 1 subequal to article 2 length; article 3 length 0.20 times article 1; primary flagellum with 59 articles; accessory flagellum 7-articulate. Antenna 2 article 4 length 1.1 times article 5; flagellum with 24 articles.Mandible accessory setal row with 7 robust setae; palp 3- articulate; article 2 without setae; article 3 length 3.5 times width. Lower lip outer plates weakly notched; lateral lobes subequal to medial lobes, without apical ducts, mandibular lobes with curved margins, subacute apically. Maxilla 1 inner plate with 1 plumose seta; outer plate palp slender, article 2 with 4 robust setae.

Pereon. Coxae 1–4 longer than broad. Gnathopod 1 larger and stouter than gnathopod 2; coxa 1 smaller than coxa 2, anterior margin straight, anteroventral corner weakly produced, subacute, posterior margin with tuft of long slender setae; basis longer than coxa, posterior margin with clusters of sparse slender setae, with single anterodistal lobe large, rounded, with 3 slender setae; ischium anterior margin with small lobe; merus anterodistal corners subacute; carpus subtriangular, length 1.5 times width, 0.7 times propodus length; propodus subovoid to subrectangular, broad, length 1.4 times width, palm subacute, deeply excavate, defined by subquadrate corner with 1 robust seta, palm length 0.5 times posterior margin; dactylus subequal in length to palm, apically acute, tapering evenly, inner margin crenate. Gnathopod 2 coxa posterior with tuft of long slender setae; basis longer than coxa, with single anterodistal lobe large, rounded, not reaching beyond ischium, anterodistal corner with 3 slender setae; ischium anterior margin without lobe; merus posteroventral corners subacute; carpus subtriangular, length 1.2 times width, 0.7 times propodus length; propodus subrectangular, length 1.9 times width, palm subacute, concave, defined by subquadrate corner with 1 robust seta, palm length 0.4 times posterior margin; dactylus subequal in length to palm, apically acute, tapering evenly, inner margin crenate.

Pleon. Epimera 1–3 subquadrate, posterior margin straight, posterodistal corner rounded. Uropod 1 long, reaching past uropod 2 rami; peduncle length with 7 robust setae, without slender setal fringe, with large, acute distoventral spine; inner ramus 1.1 times peduncle length, longer than outer ramus, with 7 marginal robust setae; outer ramus slender with 5 marginal robust setae. Uropod 2 peduncle with small distoventral spine, with 2 robust setae; inner ramus longer than outer ramus, with 1 marginal robust seta; outer ramus with 6 marginal robust setae. Uropod 3 peduncle length 1.5 times width, 0.9 times rami length with 2 marginal robust setae, 5 distal robust setae; rami long, length twice breadth; inner ramus with 3 distal robust setae, 5 distal slender setae and 2 lateral robust setae; outer ramus subequal in length to inner ramus with 1 large and 1 small curved apical robust setae, lateral setal fringe and 3 lateral robust setae. Telson subovoid, apically rounded, with small apical cusps, 5 pair of lateral setae, 2 pair of lateral plumose setae and 2 rows of oblique medial setae.

Remarks. Paragrubia dwyeri sp. nov. owes its generic position to the enlarged gnathopod 1, which is also larger than gnathopod 2. Paragrubia dwyeri sp. nov. and P. e d g a r i can be distinguished from P. vorax and P. latipoda by the unproduced gnathopod 1 coxa. Paragrubia dwyeri sp. nov. can be separated from P. edgari , P. vorax and P. latipoda by the concave palm of gnathopod 2. See also comments for P. cassini sp. nov.

Distribution. Indian Ocean: Christmas Island (current study). Western Australia: Cassini Island (current study).

Figures

FIGURE 52. Paragrubia dwyeri sp. nov., holotype male, 11.5 mm, AM P. 90117, Smiths Point, Christmas Island, Indian Ocean.

FIGURE 53. Paragrubia dwyeri sp. nov., holotype male, 11.5 mm, AM P. 90117, Smiths Point, Christmas Island, Indian Ocean, scales 0.1 mm.

FIGURE 54. Paragrubia dwyeri sp. nov., male, 15.1 mm, WAM C 45858, Cassini Island, Kimberley, Western Australia, scales 0.1 mm.