Paradexamine levitelson, Myers & LeCroy, 2009

Myers, Alan A., 2009, Dexaminidae *, Zootaxa 2260 (1), pp. 393-424 : 408-411

Paradexamine levitelson sp. nov.

( Figs 11 , 12 , Pl. 3C)

Type Material. Holotype, female, 3.0 mm, AM P 70595, 300 m off south-east corner of Palfrey Island (14°41.71'S 145°27.06'E), coral rubble, 3.7 m, R. T. Springthorpe, J.K. Lowry ( QLD 1622 ) . Paratypes, 1 male, 3 females, AM P78004, same data as holotype .

Additional material examined. 1 male, 2 females, AM P70617 ( QLD 1621 ) ; 1 female, AM P70625 ( QLD 1621 ) ; 1 female, AM P70637 ( QLD 1621 ) ; 1 female, AM P70671 ( QLD 1646 ) ; 1 male, AM P70829 ( QLD 1666 ) ; 1 female, AM P70855 ( QLD 1689 ) ; 1 male, 1 juvenile, AM P70990 ( QLD 1693 ) ; 1 female, AM P71148 ( QLD 1707 ) ; 1 female, 1 juvenile, AM P71161 ( QLD 1732 ) ; 1 female, AM P71194 ( QLD 1736 ) ; 1 female, AM P71238 ( QLD 1768 ) ; 1 juvenile, AM P71249 ( QLD 1766 ) ; 1 male, AM P71300 ( QLD 1761 ) ; 1 male, AM P71311 ( QLD 1779 ) ; 1 female, AM P71312 ( QLD 1779 ) ; 1 female, AM P71314 ( QLD 1779 ) ; 1 female, SEL/LZI-2-3; 33 unsexed, SEL/LZI-2-7; 1 male, 1 female, 2 juvenile, SEL/LZI-3-2.

Type Locality. Palfrey Island , Lizard Island, Queensland, Australia (14°41.71'S 145°27.06'E) .

Etymology. From the Latin 'levis' = smooth, together with telson, indicating the smooth distal margin of each telson lobe in this species.

Description. Based on holotype, female, 3.0 mm, AM P70595.

Head. Head lateral lobes rounded. Eye large, about half or less length of head, with black central core. Antenna 1 peduncle article 1 without process on posterior margin. Antenna 2 much shorter than body length; peduncle article 4 slender, parallel sided, weakly setulose; flagellum with 8–10 articles. Mandible palp absent; incisor process with robust setal row. Maxilla 1 palp elongate, more than four times as long as broad. Labium mandibular lobes obtuse. Maxilliped palp 4-articulate.

Pereon. Gnathopod 1 carpus shorter than propodus; propodus not greatly expanded distally. Gnathopod 2 carpus subtriangular, shorter than propodus. Pereopods 3–7 simple or scarcely prehensile. Pereopod 3 coxa, posterodistal corner with single spine, distal margin c ulate; dactylus more than half length of propodus. Pereopods 5–7 of uniform morphology. Pereopod 5 basis, posterior margin weakly concave, anterior margin with long robust setae. Pereopod 6 basis ovate. Pereopod 7 coxal gill present; basis strongly expanded, almost as broad as long, posterodistal margin strongly serrated.

Pleon. Segments with the following dorsal spine arrangement (from urosomite 1 forwards): 3.3.3.3.0. Epimeron 2 posteroventral corner produced into a strong spine. Epimeron 3 posterior and ventral margins smooth, with a single strong posteroventral spine. Urosome with urosomites 2–3 fused. Urosomite 1 with dorsal spine and two dorsolateral spines. Uropod 3 rami lacking long fine setae. Telson lobes distally smooth, without distal spine, with subdistal robust seta.

Male (sexually dimorphic characters). Based on paratype, male, 3.1 mm, AM P70595. Eye huge, more than half length of head. Antenna 2 length unknown; peduncle article 4 broader proximally, finely setulose; flagellum unknown. Uropod 3 rami with many long fine setae .

Habitat. Sands, coral rubble and other coarse sediments, sometimes with Udotea (green alga), Halimeda or mixed brown algae.

Remarks. This species is most similar to P. goomai J.L. Barnard, 1972a from south-western Australia in the rounded lateral cephalic lobes, crenulate distal margin of coxa 3, and smooth telson. It differs from that species, however, in having one dorsal and two subdorsal spines on pleon segment 1 (spines lacking in P. goomai ), a non-serrate coxa 2 (serrate in P. goomai ) and in having fewer and more slender robust setae on pereopods 3–7. Paradexamine levitelson also has a strongly serrate posterior margin to the basis of pereopod 7, whereas it is very weakly notched in P. goomai .

Distribution. Australia. Queensland: Palfrey Island, Lizard Island (current study).

Figures

FIGURE 11. Paradexamine levitelson sp. nov., holotype, female, 3.0 mm, AM P70595, Palfrey Island, Lizard Island, Great Barrier Reef.

FIGURE 12. Paradexamine levitelson sp. nov., holotype, female, 3.0 mm, AM P70595, paratype, male, 3.1 mm, AM P78004, Palfrey Island, Lizard Island, Great Barrier Reef.