Paragrubia cassini, 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 : 74-77

Paragrubia cassini sp. nov.

( Figs. 46 , 47 )

Type material. Holotype male, 9.5 mm, dissected, 3 slides, WAM C52225, Cassini Island, The Kimberley, Western Australia (13°56’1”S 125°37’8”E), intertidal, 25 October 2010, coll. Skipton Wooley (59/K10-Adhoc, Woodside Kimberley Survey 2010); paratype 1 male, WAM 45894, Cassini Island, The Kimberley (13°55’44”S 125°37’17”E), 1.8 m, on scuba, 16 October 2010, coll. Andrew Hosie (32/K10-T1, Woodside Kimberley Survey 2010).

Additional material examined. Western Australia: Male, dissected, 4 slides, AM P.82622, rock platform south of Greenough River mouth, south of Geraldton (28°51’46”S 114°38’04”E), 0.5 m, mixed brown algae, mainly Sargassum sp. and Cystophora sp., 30 November 2000, coll. R.A. Peart (WA 723); female, 1 slide, AM P.82623, rock platform south of Greenough River mouth, south of Geraldton (28°51’46”S 114°38’04”E), 0.5 m, fine leafed Cystophora sp., 30 November, 2000, coll. R.A. Peart (WA 721); 3 specimens, AM P.90119, rocky shore, Red Bluff, Kalbarri (27°42’S 114°09’E), 3–4 m, mixed algae and sediment on rocky shore, 10 January, 1984, coll. R.T. Springthorpe (WA 474).

Type locality. Cassini Island, The Kimberley, Western Australia (13°56’1”S 125°37’8”E).

Etymology. Named for the type locality, applied as a noun in apposition.

Diagnosis. Antenna 1 accessory flagellum 6-articulate. Mandible accessory setal row with 5 robust setae. Lower lip outer plates weakly notched, without apical ducts. Maxilla 1 outer plate palp slender, with 4 robust setae. Gnathopod 1 similar in size to gnathopod 2; coxa 1 subequal to coxa 2, anterior margin concave, anteroventral corner produced, acute; basis subequal in length to coxa, with single anterodistal lobe large, rounded; ischium anterior margin without lobe; propodus subrectangular, palm acute, excavate, defined by subquadrate corner and 1 robust seta. Gnathopod 2 basis subequal in length to coxa, with single anterodistal lobe rounded, not reaching beyond ischium, anterodistal corner without setae; ischium anterior margin with lobe; propodus subrectangular, palm subacute, sinusoidal, define by subquadrate corner and 1 robust seta. Telson apically subacute, 5 pairs of lateral slender setae.

Description of holotype. Head. Antenna 1 similar to antenna 2; article 1 length 1.1 times article 2, with distal robust setae; article 2 length 3.5 times article 3; article 3 length 0.25 times article 1; primary flagellum incomplete, with 38 articles; accessory flagellum 6-articulate. Antenna 2 article 4 length subequal to article 5; flagellum 23 articles. Mandible accessory setal row with 5 robust setae; palp 3-articulate, slender; article 2 with 1 slender setae; article 3 long, length 4 times width. Lower lip outer plates weakly notched, without apical ducts, mandibular lobes, recurved, apically subacute. Maxilla 1 inner plate with 1 slender seta; palp slender, with 4 robust setae.

Pereon. Coxae 1–4 longer than broad. Gnathopod 1 similar in size to gnathopod 2; coxa 1 subequal to coxa 2, anterior margin concave, anteroventral corner produced, acute, posteroventral corner with tuft of long slender setae; basis subequal in length to coxa, with single anterodistal lobe large, rounded; ischium anterior margin without lobe; merus anterodistal corners acute; carpus subtriangular, length 1.7 times width, 0.7 times propodus length; propodus subrectangular, length twice width, palm acute, excavate, defined by subquadrate corner and 1 robust seta, palm length 0.4 posterior margin; dactylus subequal in length to palm, apically acute, tapering evenly, inner margin crenate. Gnathopod 2 basis subequal in length to coxa, with single anterodistal lobe rounded, not reaching beyond ischium, anterodistal corner without setae; ischium anterior margin with lobe; merus anterodistal corners subacute to acute; carpus subtriangular, length 1.7 times width, 0.8 times propodus length; propodus subrectangular, length twice width, palm subacute, sinusoidal, define by subquadrate corner and 1 robust seta, palm length 0.4 posterior margin; dactylus subequal in length to palm, apically acute, tapering evenly, inner margin crenate.

Pleon. Epimeron 1 rounded, posterior margin convex, posterodistal corner with small acute tooth. Epimera 2– 3 subquadrate, posterior margin straight, posterodistal corner with small acute tooth. Uropod 1 long, reaching past uropod 2 rami; peduncle length 2.5 times width, with 6 robust setae, with large, acute distoventral spine; inner ramus 1.1 times peduncle length, longer than outer ramus, with 4 marginal robust setae; outer ramus broad with 2 marginal robust setae. Uropod 2 peduncle without distoventral spine, with 2 robust setae; inner ramus longer than outer ramus, with 4 marginal robust setae; outer ramus with 5 marginal robust setae. Uropod 3 peduncle length 1.3 times width, 1.2 times rami length, with 2 marginal robust setae, 3 distal robust setae and 1 distal slender seta; inner ramus length twice breadth, with 3 distal robust setae, 2 distal slender setae and 2 lateral robust setae; outer ramus with 1 straight distal robust seta, without marginal robust setae. Telson subtrapezoidal, apically subacute, with small apical cusps, 5 pairs of lateral slender setae and 2 pairs of lateral plumose setae.

Remarks. Paragrubia cassini sp. nov. is most similar to P. dwyeri sp. nov. and P. pilipes with both species having the combination of both gnathopods enlarged and the gnathopod 1 propodus palm excavate. These species can be distinguished from each other by the gnathopod 2 propodus palm, which is sinusoidal in P. cassini sp. nov. and concave in P. dwyeri sp. nov. and P. pilipes .

Distribution. Western Australian: The Kimberley, Kalbarri, Geralton (current study).

Figures

FIGURE 46. Paragrubia cassini sp. nov., holotype male, 9.5 mm, WAM C 52225, Cassini Island, The Kimberley, Western Australia.

FIGURE 47. Paragrubia cassini sp. nov., holotype male, 9.5 mm, WAM C 52225, Cassini Island, The Kimberley, Western Australia, scales 0.1 mm.