Mallacoota balara Berents, 1983

Lowry, J. K. & Hughes, L. E., 2009, Maeridae, the Elasmopus group *, Zootaxa 2260 (1), pp. 643-702 : 669-673

Mallacoota balara Berents, 1983

( Figs 15 , 16 , Pl. 4F)

Mallacoota balara Berents, 1983: 133 , figs 25, 26. — Springthorpe & Lowry, 1994: 10 (catalogue). — Lowry & Stoddart, 2003: 182 (catalogue).

Material examined. 3 unsexed, AM P75882 (76 LIZ A 03.15.1) ; 5 unsexed, AM P75894 (76 LIZ A 03.15.1) ; 5 unsexed, AM P75821 (76 LIZ A 03.15.2) ; 2 unsexed, AM P75823 (76 LIZ A-6.18.3) ; 1 unsexed, AM P75886 (76 LIZ A 9.12.1) ; 7 unsexed, AM P75824 (76 LIZ A 9.18.3) ; 1 unsexed, AM P75891 (76 LIZ B 3 ) ; 1 unsexed, AM P75820 (76 LIZ B 00.03.1) ; 6 unsexed, AM P75885 (76 LIZ B 03.12.2) ; 2 unsexed, AM P75893 (76 LIZ B 03.12.3) ; 1 unsexed, AM P75892 (76 LIZ B 4 ) ; 6 unsexed, AM P75890 (76 LIZ B 6.18.3) ; 7 unsexed, AM P75888 (76 LIZ B.06.18.3) ; 3 unsexed, AM P75822 (76 LIZ B 09.15.2) ; 1 unsexed, AM P75884 (76 LIZ B 09.15.3) ; 3 unsexed, AM P75818 (76 LIZ B 9.18.1) ; 1 unsexed, AM P75819 (76 LIZ B 9.21.1) ; 3 unsexed, AM P75889 (76 LIZ B 09.21.2) ; 3 unsexed, AM P75883 (76 LIZ B 12.18.1) ; 7 unsexed, AM P75887 (76 LIZ B 12.21.2) ; 7 unsexed, AM P75817 (76 LIZ B 12.24.3) ; 1 unsexed, AM P75814 ( JDT / LIZ 5 ); 10 unsexed, AM P75816 ( JDT / LIZ 14 ); 5 unsexed, AM P70710 ( QLD 1637 ); 4 unsexed, AM P70678 ( QLD 1641 ); 1 unsexed, AM P70785 ( QLD 1670 ); 1 male , 6.6 mm, 6 slides, AM P78027 ( QLD 1670 ); 7 unsexed, AM P70969 ( QLD 1687 ); 2 unsexed, AM P70861 ( QLD 1689 ); 6 unsexed, AM P70994 ( QLD 1693 ); 3 unsexed, AM P71104 ( QLD 1733 ); 1 female , 5.9 mm, 5 slides, AM P78028 ( QLD 1733 ); 1 unsexed, AM P71196 ( QLD 1736 ); 2 unsexed, AM P71273 ( QLD 1773 ); 1 unsexed, AM P71322 ( QLD 1781 ); 1 unsexed, AM P75815 ( QLD 1787 ); 2 unsexed, AM P71465 ( QLD 1797 ) .

Type locality. Fringing reef between Bird Islet and South Island, Lizard Island Great Barrier Reef (14°42'S 145°28'E) .

Description. Based on male, 6.6 mm, AM P78027.

Head. Head eyes ovate; lateral cephalic lobe broad, truncated, anteroventral margin with notch/slit, anteroventral corner rounded. Antenna 1 longer than antenna 2; peduncular article 1 subequal in length to article 2, with 1 robust seta on posterior margin; article 2 longer than article 3; accessory flagellum short, with 3 articles; flagellum with 21 articles. Antenna 2 peduncular article 4 longer than article 5; flagellum with 8 articles. Mandible incisor a smooth cutting edge with 2 apicomedial cusps; accessory setal row with 3 setae; palp reduced, 3-articulate; article 1 about twice as long as broad, longer than article 2, inner margin article 1 not produced distally; article 2 shorter than article 3; article 3 short (about 3 x as long as broad), rectolinear, subequal to article 1.

Pereon. Gnathopod 1 coxa anteroventral corner produced, rounded, anterior margin concave; merus without posterodistal tooth; carpus about 2 x as long as broad, carpus subequal in length to propodus, setae in anterodistal bunches and along posterior margin; propodus palm acute, straight, entire, defined by posterodistal corner, with posterodistal robust setae. Gnathopod 2 coxa posteroventral corner notch present; basis broad; merus with subquadrate distoventral corner; carpus compressed, projecting between merus and propodus; propodus expanded, without setal bunches along posterior margin, palm slightly acute, concave, sculptured, palm about half length of propodus, with slight subtriangular distomedial shelf, without group of robust setae on shelf, with slight midmedial excavation, palmar margin with 2 robust setae, with subacute tooth, subpalmar surface with platform, with posteroventral corner, with 1 posterodistal robust seta; dactylus reaching end of palm, closing into socket, without setae on anterior margin, without posteroproximal shelf, apically subacute. Pereopod 5 basis expanded, posterior margin slightly concave, without long slender setae, posteroventral corner broadly rounded; carpus and propodus with few long, slender setae along anterior margin. Pereopod 6 basis posterior margin straight, without long slender setae, posteroventral corner broadly rounded; carpus and propodus with many long, slender setae along margins; merus and carpus broadened; propodus not expanded posterodistally. Pereopod 7 basis posterior margin convex, smooth, without long slender setae, produced posterodistally (lobate), posteroventral corner broadly rounded; merus and carpus broadened; propodus not expanded posterodistally.

Pleon. Pleonites 1–3 dorsally smooth, without setae, spines or carinae. Epimeron 1 posteroventral corner with small acute spine. Epimeron 2 posteroventral corner acute. Epimeron 3 ventral margin smooth, posteroventral margin smooth, posteroventral corner with small acute spine. Urosomites 1–3 without dorsal spines. Urosomite 1 bicarinate. Urosomites 2–3 dorsally smooth, without setae, spines or carinae. Uropod 1 peduncle with basofacial robust seta. Uropod 3 rami distally truncated, apical robust setae long or short; inner ramus subequal in length to outer ramus, short (length less than 2 x breadth); outer ramus short (length x x breadth), slightly longer than peduncle, 1-articulate. Telson moderately cleft (30 to 65%), broader than long, short, truncated distally, apical margins concave, apical conical extension reaching scarcely one third along longest seta, without dorsal robust setae, with apical/subapical robust setae, each lobe with 4 apical robust setae, apical robust setae long or short, without robust setae on outer or inner margins.

Female (sexually dimorphic characters). Based on paratype female, 8 mm, AM P30134. Gnathopod 2 carpus long; propodus subrectangular, palm acute with broadly rounded corner, straight, smooth, without distomedial shelf, without robust setae along palm, subpalmar distomedial surface smooth .

Habitat. Marine, epibenthic, living among algae.

Remarks. Only three species on the GBR have a well defined corner on the palm of male gnathopod 2: M. balara , M. chandaniae and M. scopulosa . Mallacoota balara differs from the latter two in not having a tooth define the palmar corner and in having a broad basis on the male gnathopod 2.

Distribution. Australia. Queensland: Lizard Island ( Berents 1983, current study).

Figures

FIGURE 15. Mallacoota balara Berents 1983, male, 6.6 mm, AM P78027, Lizard Island, Great Barrier Reef.

FIGURE 16. Mallacoota balara Berents 1983, male, 6.6 mm, AM P78027, female, 5.9 mm, AM P78028, Lizard Island, Great Barrier Reef.