Aborolobatea insidiosa, Hughes & Lowry, 2009

Hughes, L. E. & Lowry, J. K., 2009, Oedicerotidae *, Zootaxa 2260 (1), pp. 746-758 : 747-750

Aborolobatea insidiosa sp. nov.

( Figs 1 , 2 )

Type material. Holotype, female (dissected), 3 slides, 4.0 mm, AM P78121, First Lagoon , One Tree Island, Queensland, Australia (~ 23°30'S 152°05'E), night plankton tow, low tide, F.H. Talbot, 4 December 1966 (FT 107) . Paratypes: 1 male (dissected), 3 slides, 4.0 mm, AM P78122 (FT 107); 25+ unsexed, AM P78196 (FT 107) .

Additional material examined. 5 unsexed, AM P78123 ( JDT / OPH 11b); 3 unsexed, AM P78124 ( JDT / OPH 11); 1 unsexed, AM P78125 ( JDT / OPH 11); 3 unsexed, AM P78126 ( JDT / OPH 13); 4 unsexed, AM P78127 ( QLD 46); 1 unsexed, AM P28489; 3 unsexed, AM P78128 ( QLD 1935); 6 unsexed, AM P78129 ( QLD 1936); 25+ unsexed, AM P78130 ( QLD 1948); 5 unsexed, AM P78131 ( QLD 1955); 13 unsexed, AM P78132 ( QLD 1964); 15+ unsexed, AM P78133 ( QLD 1979).

Type locality. First Lagoon , One Tree Island (~ 23°30.2’S 152°5.3’E) .

Etymology. From the Latin ‘insidiosum’ meaning ‘lying in wait’ and alluding to the oedicerotid behavour as an ambush predator.

Description. Based on holotype, female, 4.0 mm, AM P78121.

Head. Head rostrum well developed, broad, strongly deflexed, apically acute; eyes subovate, not coalesced, situated fully within head; lateral cephalic lobe absent. Antenna 1 long, exceeding article 5 on antennae 2; peduncle sparsely setose; peduncular articles 1–2 shorter than peduncle of antenna 2; peduncular article 1 without tooth, subequal in length to article 2, shorter than article 3; peduncular article 3 elongate, subequal to article 2; flagellum without callynophore; without calceoli. Antenna 2 peduncle sparsely setose, not greatly enlarged; flagellum without calceoli. Mandible molar reduced, not triturative, with tuft of setae; incisor left and right a straight, smooth blade; palp stout; article 2 straight, distally expanded with 9 slender setae; article 3 slightly shorter than article 2, falcate with many marginal setae. Lower lip inner lobes unknown; mandibular lobes slender, twice as long as broad directed axially. Maxilla 1 outer plate with 9 setal-teeth; inner plate with 2 apical setae. Maxilla 2 inner plate without oblique setal row. Maxilliped inner plate absent; palp article 2 greatly enlarged distal end, article 3 expanded distally, dactylus recurved at tip.

Pereon. Gnathopods 1–2 well developed; propodi similar in shape. Gnathopod 1 subequal in size to gnathopod 2; weakly chelate; carpal lobes absent; propodus subrectangular (about 2 x as long as broad), propodus posterodistal margin smooth, palm slightly obtuse margin smooth. Gnathopod 2 weakly chelate; carpus extremely elongate, 2.6 x longer than broad, carpal lobes absent; propodus subrectangular (about 3 x as long as broad), posterodistal margin smooth, palm obtuse. Pereopods 3–4 carpi and propodi subequal in length; propodi posterior margins setose, dactyli minute, shorter than propodi, without apical setae. Pereopod 3 coxa anterior margin straight, anteroventral corner not produced, ventral margin convex. Pereopod 4 coxa ventral margin convex, with small posteroventral lobe. Pereopods 5–6 similar in form; propodi posterior margins sparsely setose; dactyli shorter than propodi, slender, tapering, without ungues. Pereopod 5 coxa small, depth distinctly less than coxa 4; merus not enveloping carpus. Pereopod 7 basis with tapering margins, posterodistal lobe absent.

Pleon. Epimeron 3 posterior distal corner rounded. Uropod 1 rami without setae; outer ramus shorter, about half length of inner; inner ramus smooth. Uropod 2 rami with small robust setae; rami subequal. Uropod 3 not greatly enlarged; rami with small robust setae; rami subequal in length. Telson apically truncate and slightly emarginate, with 2 apical robust setae.

Habitat. Shallow sand bottoms.

Remarks. Aborolobatea insidiosa differs from A. paracheliformis Ledoyer, 1984 , as follows: rostrum sharply deflexed (slightly deflexed in A. paracheliformis ); mandibular palp article 2 distally broadened (slightly expanded medially in A. paracheliformis ), article 3 long and slender (short and broad in A. paracheliformis ); maxilliped palp article 3 broad (slender in A. paracheliformis ); lower lip mandibular lobes narrow and directed axially (broad and directed down in A. paracheliformis ); gnathopods 1–2 with obtuse palms (transverse in A. paracheliformis ); and subequal uropod 2 rami (outer ramus slightly shorter in A. paracheliformis ).

Aborolobatea insidiosa sp. nov. is the second species described in the genus and is a common, widespread species on the Great Barrier Reef. It can be distinguished from other oedicerotids on the GBR by the weakly chelate gnathopods 1–2 without carpal lobes; and the uropod 1 outer ramus which is much shorter than the inner ramus.

Distribution. Australia. Queensland: Lizard Island (current study); Fantome and Orpheus Islands (current study); One Tree Island (current study).

Figures

FIGURE 1. Aborolobatea insidiosa sp. nov., holotype, female, 4.0 mm, AM P78121, First Lagoon, One Tree Island, Great Barrier Reef.

FIGURE 2. Aborolobatea insidiosa sp. nov., holotype, female, 4.0 mm, AM P78121, First Lagoon, One Tree Island, Great Barrier Reef.