Platyischnopus mam Barnard & Drummond, 1979

Hughes, L. E., 2009, Platyischnopidae *, Zootaxa 2260 (1), pp. 828-835 : 828-829

Platyischnopus mam Barnard & Drummond, 1979

( Figs 1 , 2 , Pl. 6A)

? Platyischnopus mirabi 1is. — Chilton, 1922: 4, fig. 1 (not Stebbing, 1888).

Platyischnopus mam Barnard & Drummond, 1979: 11 , figs 6–8. — Barnard & Karaman, 1991: 642. — Lowry & Stoddart, 2003: 242.

Material examined. 27 unsexed AM P75486 (JDT/ OPH 6 ) ; 1 male AM P75487 (JDT/ OPH 7 ) ; 4 unsexed AM P75488 (JDT/ OPH 11 ) ; 1 male, 8.5 mm, AM P75482 (JDT/ OPH 13 ) ; 2 unsexed AM P75489 (JDT/ OPH 13 ) ; 1 unsexed AM P75490 (JDT/ OPH 13 ) ; 1 male dissected, 5.7 mm, 3 slides, AM P75481 ( JML Plankton tow night Oct 1979); 4 unsexed AM P75483 ( JML Plankton tow night Oct 1979); 9 unsexed, AM P75484 ( JML 16.10.9); 4 unsexed, AM P75845 ( JML 20.10.2); 1 unsexed AM P70692 ( QLD 1640 ); 2 unsexed, photo 1, AM P70811 ( QLD 1654 ); 1 unsexed, AM P70868 ( QLD 1654 ); 1 male , 7.0 mm, whole animal drawing, AM P70838 ( QLD 1666 ); 2 unsexed, AM P70839 ( QLD 1666 ); 1 female dissected, 6.5 mm, 3 slides, AM P75480 ( QLD 1672 ); 3 unsexed, AM P70909 ( QLD 1672 ); 1 unsexed, AM P75491 ( QLD 1999 ) .

Type locality. Jibbon point, off Cronulla, New South Wales, Australia (34 ° 05’S 151 ° 13’E) .

Description. Based on female, 6.5 mm, AM P75480.

Head. Head with lateral keel; rostrum with apical constriction, or with weak apical constriction. Eyes present. Antennae 1 article 2 elongate, greater than 1.1 times article 1; flagellum 6 articles; accessory flagellum 3-articulate. Antennae 2 brush setae present (in male); flagellum with 4 articles. Upper lip subovoid, apically rounded. Mandible accessory setal row absent; mandibular molar subovoid, mandilbular molar large, (covering more than 1/2 of medial surface); mandibular palp article 2 subequal to article 3, article 2 without setae, article 3 with apical setae. Lower lip mandibular lobes weakly produced, apically rounded, with lobes directed laterally. Maxilla 1 palp short, extending to end of outer plate, with 3 apical setae; inner plate with 1 seta. Maxilla 2 outer plate with many apical setae; inner plate with many apical setae. Maxilliped dactylus unguis well developed, articulate.

Pereon. Gnathopod 1 chelate; coxa large, similar in size to coxa 2, broader than long, anterior margin produced, apically rounded; carpus longer than propodus, around five times as long as broad; propodus about twice as long as broad, chela short, obtuse projection as broad as long. Gnathopod 2 chelate; carpus longer than propodus, twelve times as long as broad; propodus about four times as long as broad, chela long, obtuse projection twice as broad as long. Pereopods 3–4 articles rectolinear; dactylus simple, about 1/3 length of the propodus. Pereopod 3 coxa tapering distally. Pereopod 4 coxa anteriodistal margin not produced, posteroventral lobe absent. Pereopod 5 coxa posterior lobe anterior margin straight or weakly so; basis about twice as long as broad, posterodistal lobe well developed. Pereopod 6 coxa posterior lobe short, extending less the half the length of the basis, with robust setae; basis subovoid; merus broader than long. Pereopod 7 basis posterior margin acutely produced; carpus as long as broad; propodus 5 x as long as broad; dactylus short, half the length of the propodus.

Pleon. Pleonites 1–3 without dorsal teeth. Epimeron 1 posterodistal corner rounded. Epimera 2–3 posterodistal corner subquadrate. Uropod 1 peduncle with 7 robust setae. Uropod 2 peduncle with 4 robust setae; inner ramus shorter than outer ramus. Uropod 3 outer ramus well developed, article 2 with 3 sets of lateral robust setae. Telson notched, without dorsofacial robust setae, lateral robust setae present, with a pair of apices.

Habitat. Sublittoral sandy bottoms.

Remarks. The specimens from Lizard and Orpheus Island, Queensland agree with the original material described from Jibbon point, in New South Wales. The only difference is the presence of two robust setae on the peduncle of uropod 1 in the Queensland material while the New South Wales material has one robust setae.

Adult males specimens, recorded here for the first time, have an elongate antennae 2 which may be two thirds to longer than the length of the body and an anterodorsal notch on urosomite 1. In the larger adult specimens (7.0 mm) the pereopod 7 basis develops a more acute posterior attenuation ( Fig. 1 , P7).

There also appears to be some variation in the apical constriction of the rostrum, with a few of specimens with a weak and others a strong constrictions. This may however be an artefact of shrivelling upon preservation, as the majority of specimens examined are without a constricted rostrum. The aberrant constricted material shows no other morphological variation from the type form.

Distribution. Australia. Queensland: Lizard Island; Fantome Island; Orpheus Island; One Tree Island (current study). New South Wales: Cronulla ( Barnard & Drummond 1979).

Figures

FIGURE 1. Platyischnopus mam Barnard & Drummond, 1979, female, 6.5 mm, AM P75480, Head, P7 and Ur male 7.0 mm, AM P70838, Lizard Island, Great Barrier Reef.

FIGURE 2. Platyischnopus mam Barnard & Drummond, 1979, female, 6.5 mm, AM P75480, Lizard Island, Great Barrier Reef.