Colomastix lunalilo J.L. Barnard, 1970

LECROY, SARA E., 2009, Colomastigidae *, Zootaxa 2260 (1), pp. 348-372 : 356-357

Colomastix lunalilo J.L. Barnard, 1970

( Figs 5 , 6 )

Colomastix lunalilo J.L. Barnard, 1970: 96–100 , figs 51, 52. — J.L. Barnard, 1971: 55, figs 24, 25. — Ledoyer, 1979: 26,

fig. 9(2). — Ledoyer, 1982: 156–157, fig. 54. — Myers, 1985: 56, fig. 41. — Lyons & Myers, 1990: 1222, fig. 20. —

Müller, 1992: 426.? Colomastix lunalilo — Ledoyer, 1978: 233, fig. 15(2). Not Colomastix lunalilo — Hirayama, 1990: 21–24, figs 1–3 (= Colomastix japonica Bulycheva, 1955 ). Not Colomastix lunalilo — Kim & Kim, 1987: 9, fig. 8 (=? Colomastix japonica Bulycheva, 1955 ).

Material examined. 1 female, AM P78984 ( JDT / LIZ 3 ) ; 2 males, GCRL 2872 ( JDT / LIZ 14 ) ; 1 female, GCRL 2871 ( JDT / LIZ 15 ) ; 1 male, AM P78985 ( JDT / OPH 1 ) ; 2 males, AM P37540 ( QLD 11 ) ; 1 male, 1 female, AM P70801 ( QLD 1649 ) ; 1 male, 1 female, AM P70967 ( QLD 1687 ) ; 1 female, AM P70998 ( QLD 1707 ) ; 1 female, AM P71139 ( QLD 1707 ) .

Type locality. Kaneohe Bay, Oahu , Hawaii .

Description. Based on 1 male, AM P70801 and 1 male, AM P70967.

Head. Head as long as deep, subequal in length to pereon segment 1 and half of pereon segment 2 combined; rostrum subacute; interantennal plate with anteroventral angle extending slightly beyond anterodorsal angle, anterior margin straight to slightly concave, without serrations, with 2 ventral teeth. Antennae 1–2 marginal robust setae elongate. Antenna 1 peduncle article 1, dorsomedial margin with 4 robust setae. Antenna 2 peduncle articles 3–5, ventrolateral margin without small, triangular robust setae; peduncle article 3, distomedial angle with 1 robust seta, without slender setae or process, dorsomedial margin with 1 robust seta, ventromedial surface with 2 robust setae; peduncle article 5, dorsal margin without stubby robust setae. Mouthparts other than maxilliped moderately reduced. Maxilliped, inner plates completely fused, basal shell expanded to form a ventral keel, keel distally flattened.

Pereon. Coxa 1 anterior margin strongly concave, anteroventral angle narrowly produced. Coxae 1–4 with small anteroventral cusp. Coxal gills 2–5 gradually increasing in size, gill 6 subequal to gill 5. Gnathopod 1 elongate, slender; propodus with pectinate apical setae. Gnathopod 2 basis moderately expanded distally, anterior margin entire, without anterodistal notch, without anterodistal process; ischium with inner anterodistal lobe expanded; carpus much shorter than propodus, inner ventral surface with patch of setae, setae short, very fine; propodus greatly enlarged, inner ventral surface with patch of setae, setae elongate, slender, palm not excavate, with 2 dissimilar processes, palmar angle with 1 short subtriangular process, apical margin of process entire, middle process absent, process at dactylar hinge broad, rounded; dactylus, insertion on propodus apical, with small process on posterior margin, tip lanceolate, subacute. Pereopods 3–4 basis not produced anterodistally. Pereopods 3–7 basis slightly expanded. Pereopod 7 propodus, anterior margin with 2 robust setae.

Pleon. Pleopods 1–3 inner ramus with 4 articles, outer ramus with 5 articles. Pleopod 2 peduncle, anteromedial surface with 3 slender setae. Uropod 1 inner ramus modified, not strongly falcate, not expanded proximally, ventral margin straight, tip minutely attenuate, recurved, with 2–4 subapical robust setae dorsally; outer ramus slightly shorter than inner ramus, tip lanceolate, subacute. Uropod 2 both rami, ventral margin lacking setae. Uropod 3 peduncle less than twice as long as deep; inner ramus blade-like, approximately 3 x length of outer ramus, medial surface with proximal, curved diagonal ridge, ridge entire, without minute robust setae. Telson broadly subtriangular, dorsal surface flat, tip subtruncate, without lobes or processes, with 2 apical short slender setae.

Female (sexually dimorphic characters). Based on 1 female, AM P70801 and 1 female, AM P70967. Head deeper than long, subequal in length to pereon segment 1. Oostegite 2 subovate (length:width ratio approximately 2:1), approximately one-third longer than basis of gnathopod 2. Gnathopod 2, basis weakly expanded distally, ischium with inner anterodistal lobe not expanded; carpus slightly shorter than propodus; propodus unenlarged, inner ventral surface with patch of setae, setae short, very fine or setae elongate, slender, palm without teeth or processes; dactylus, insertion on propodus subapical, without process on posterior margin. Pleopod 2 peduncle, anteromedial surface without slender setae. Uropod 1 inner ramus unmodified, lanceolate; outer ramus subequal to inner ramus .

Adult body length. 1.9–3.0 mm. There appears to be little difference in size between males and females in this species.

Colour in life. Eyes red. Antennae 1–2 with faint bands of rusty orange; body with a very faint rusty orange wash over translucent grey, darkest anteriorly; pereopods with very faint banding.

Host. Unknown.

Habitat. Corals, coral rubble, algae ( Caulerpa , Sargassum , Halimeda ) and coralline algae in reef flat and patch reef habitats.

Depth range. 1–24 m.

Remarks. Colomastix lunalilo appears to be one of the most widely distributed of the Colomastix species , occurring from the Central Pacific through the Indian Ocean to the Red Sea. However, although it has been reported from Bora Bora in the Society Islands ( Müller 1992) and from Fiji ( Myers 1985), this constitutes the first record of this species from the Great Barrier Reef.

Colomastix lunalilo can be distinguished from all but five other species in the genus by the elongate, blade-like inner ramus of uropod 3. Of these five, C. brazieri from south-eastern Australia is the most poorly known, but is readily distinguished from C. lunalilo by its larger size (10 mm) and the longer outer ramus of uropod 3. Colomastix magnirama , a New Zealand species, differs from C. lunalilo in the tiny, almost vestigial, outer ramus of uropod 3 and the presence of a large posteroventral carpal lobe on pereopods 5–7. The Red Sea species, C. laminosa , differs from C. lunalilo in the longer outer ramus of uropod 3, the lack of robust setae on the anterior margins of pereopod propodi 5–7 and the produced, acutely pointed anterior lobe of coxa 5. The remaining two species, C. japonica and C. dentipalma sp. nov., also occur on the Great Barrier Reef, but are distinguished from C. lunalilo by the more anteriorly extended ventral angle of the interantennal plate, the presence of an anteroventral notch on the basis of gnathopod 2 in the male, the longer outer ramus of uropod 3 and the more narrowly subtriangular telson.

Distribution. U.S.A. Hawaii ( Barnard 1970, 1971). Fiji. Nasese and Momi Bay, Viti Levu ( Myers 1985). Australia. Lizard and Orpheus Islands, Queensland (current study). French Polynesia. Bora Bora, Society Islands ( Müller 1992). Indian Ocean.? Mauritius ( Ledoyer 1978). Madagascar. Grand Récif de Tuléar ( Ledoyer 1979, 1982). Red Sea. Gulf of Aqaba ( Lyons & Myers 1990).

Figures

FIGURE 5. Colomastix lunalilo J.L. Barnard, 1970, male, 3.4 mm, female, 3.0 mm, AM P70967, 200 m north of Bird Islet, Lizard Island, Great Barrier Reef.

FIGURE 6. Colomastix lunalilo J.L. Barnard, 1970, male, 3.4 mm, female, 3.0 mm, AM P70967, 200 m north of Bird Islet, Lizard Island, Great Barrier Reef.