Colomastix plumosa Ledoyer, 1979: 26 Ledoyer, 1982: 158–159 Lyons & Myers, 1990: 1220– 1221 Ariyama, 2005: 27–31 Colomastix pusilla Nayar, 1966: 145 Colomastix pusilla Grube, 1861: 137 Colomastigidae * LECROY, SARA E. Zootaxa 2009 2009-10-08 2260 1 348 372 5ZMV2 Ledoyer, 1979 Ledoyer 1979 [151,579,151,177] Malacostraca Colomastigidae Colomastix Animalia Amphipoda 12 360 Arthropoda species plumosa  ( Figs 7, 8)      Colomastix plumosa Ledoyer, 1979: 26, fig. 8(1). —  Ledoyer, 1982: 158–159, fig. 55. —  Lyons & Myers, 1990: 1220– 1221, fig. 18. —  Ariyama, 2005: 27–31, figs 19–22.  ?  Colomastix pusilla. —  Nayar, 1966: 145, fig. 7 (not   Colomastix pusilla Grube, 1861: 137).   Material examined.  1 male, AMP79275 ( JDT/ LIZ 3);  1 male, AMP79276 ( JDT/ LIZ 5);  1 male, GCRL 2873( JDT/ LIZ 5);  1 male, AMP79277 ( JDT/ LIZ 7);  1 male, AMP79278 ( JDT/ LIZ 12);  3 males, 1 female, AMP79279 ( JDT/ LIZ 13);  1 female, GCRL 2874( JDT/ LIZ 13);  1 male, AMP79280 ( JDT/ LIZ 14);  2 males, 1 female, AMP79281 ( JDT/ OPH 1);  1 juvenile, AMP79282 ( QLD 11);  1 juvenile, AMP37541 ( QLD 27);  1 female, AMP70593 ( QLD 1622);  1 female, AMP70709 ( QLD 1643);  1 juvenile, AMP70735 ( QLD 1643);  1 female, AMP79283 ( QLD 1760);  1 female, AMP79284 ( QLD 1760);  1 juvenile, AMP71325 ( QLD 1786);  1 male, AMP71434 ( QLD 1792).    Typelocality. Grand Récif de Tuléar, Madagascar( 23°20’S 43°41’E).   Description.Based on 1 male, AM P79278 (JDT/LIZ 12); 2 males, AM P79281 (JDT/OPH 1).  Head. Headlonger than deep, slightly longer than first two pereon segments combined; rostrum narrowly rounded; interantennal plate with anterodorsal and anteroventral angles extending forward subequally, anterior margin straight to slightly concave, without serrations, without ventral teeth. Antennae 1–2marginal robust setae short. Antenna 1peduncle article 1, dorsomedial margin with 2 robust setae. Antenna 2peduncle articles 3–5, ventrolateral margin with small, triangular robust setae; peduncle article 3, distomedial angle with 1 robust seta and 1 elongate slender seta, without process, dorsomedial margin and ventromedial surface without robust setae; peduncle article 5, dorsal margin with stubby robust setae. Mouthpartsother than maxilliped greatly reduced or vestigial. Maxilliped, inner plates completely fused, basal shell not expanded to form a ventral keel.  Pereon. Coxa 1anterior margin convex, anteroventral angle rounded. Coxae 1–4without small anteroventral cusp. Coxal gills2–5 gradually increasing in size, gill 6 smaller than gill 5. Gnathopod 1vestigial, exact morphology individually variable; propodus without setae. Gnathopod 2basis broadly expanded distally, anterior margin entire, without anterodistal notch, without anterodistal process; ischium with inner anterodistal lobe not 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 3 similar, equally spaced processes, palmar angle with 1 short subtriangular process, apical margin of process entire, middle process slightly smaller than proximal process, subacute, process at dactylar hinge medium, subtriangular; dactylus, insertion on propodus apical, with small process on posterior margin, tip lanceolate, subacute. Pereopods 3–4basis not produced anterodistally. Pereopods 3–7basis slightly expanded. Pereopod 7propodus, anterior margin without setae.  Pleon. Pleopods 1–3inner ramus with 4 articles, outer ramus with 4 articles. Pleopod 2peduncle, anteromedial surface with 3 slender setae. Uropod 1inner ramus modified, not strongly falcate, expanded proximally, ventral margin straight, tip subtruncate; outer ramus three-fourths length of inner ramus, tip lanceolate, subacute. Uropod 2both rami, ventral margin lacking setae. Uropod 3peduncle less than twice as long as deep; inner ramus lanceolate, subequal to outer ramus, ventral margin lacking setae.  Telsonbroadly subtriangular, dorsal surface flat, tip subtruncate, without lobes or processes, with 2 subapical short slender setae.  Female(sexually dimorphic characters). Based on 1 female, GCRL 2874 and 1 female, AM P79281 (JDT/OPH 1). Headas long as deep, subequal in length to pereon segment 1 and half of pereon segment 2 combined. Antenna2 peduncle article 5, dorsal margin without stubby robust setae. Mouthpartsother than maxilliped moderately reduced. Oostegite 2narrowly subovate (length:width ratio 3:1 or greater), slightly longer than basis of gnathopod 2. Gnathopod 1elongate, slender; propodus with simple apical setae. Gnathopod 2basis weakly expanded distally; carpus subequal to propodus in length, inner ventral surface with patch of setae, setae elongate, very fine; propodus unenlarged, inner ventral surface with patch of setae, setae elongate, very fine, palm without teeth or processes; dactylus without process on posterior margin, tip pleated, subtruncate. Pleopod 2peduncle, anteromedial surface without slender setae. Uropod 1inner ramus unmodified, lanceolate; outer ramus subequal to inner ramus. Uropod 2both rami, ventral margin densely setose. Uropod 3inner ramus, ventral margin densely setose.   FIGURE 7.  Colomastix plumosa Ledoyer, 1979, male, 2.7 mm, AM P79278, north shore of Palfrey Island, Lizard Island; female, 2.3 mm, AM P79281, cove south of Orpheus Island Resort, Orpheus Island, Great Barrier Reef.   FIGURE 8.  Colomastix plumosa Ledoyer, 1979, male, 2.7 mm, AM P79278, north shore of Palfrey Island, Lizard Island; female, 2.3 mm, AM P79281, cove south of Orpheus Island Resort, Orpheus Island, Great Barrier Reef.  Adult body length.2.3–3.0 mm. There appears to be little difference in size between males and females in this species.  Colour in life.Eyes red. Antennae banded with reddish pink, pereon and pleon with large reddish pink blocks of pigment on translucent grey background, coxae each with a single large pigment spot proximally. This pattern is similar to that of  Colomastix processa  sp. nov.(see Colour in lifesection of  C. processa  sp. nov.for a comparison of the two species).   Host.The sponges  Spirastrella insignis Thiele, 1898and  Clathria fasciculata Wilson, 1925( Ariyama 2005).  Habitat.Corals, coral rubble, algae (  Caulerpa racemosaJ. Agardh, 1873;  Halimeda micronesica Yamada, 1941) and algal turf in reef slope, reef flat and patch reef habitats.  Depth range. 1–28 m.   Remarks.  Colomastix plumosais a fairly widespread species in the Indian Ocean and Red Sea, although it has not previously been reported from the Indo-Pacific or Pacific Oceans south of Japan. Nayar's (1966)report of  C. pusilla Grube, 1861from Indiamay actually refer to this species. He does not illustrate uropod 2 of his specimen, which appears to be either a female or a small subadult male and has a setose inner ramus on uropod 3, as do  C. plumosa,  C. semiplumosa Ariyama, 2005and  C. minispinosa Ren, 2006(possibly a synonym of  C. semiplumosa). However, uropod 1 of Nayar's material has subequal rami, resembling that of  C. plumosarather than  C. semiplumosaor  C. minispinosa, both of which have distinctly unequal rami on uropod 1 inthe female. The adult male of  C. plumosawas unknown prior to the current study. Although there are several other species of  Colomastixthat have a setose inner ramus on uropod 3 inthe female, including the Atlantic species  C. bousfieldi LeCroy, 1995,  C. heardi LeCroy, 1995and  C. falcirama LeCroy, 1995, as well as  C. semiplumosafrom Japanand  C. minispinosafrom China,  C. plumosacan be distinguished from these and all other known species of  Colomastixby the setose inner and outer rami of uropod 2 inthe female and by the simple, subtruncate tip of the inner ramus of uropod 1 inthe male. It appears to be most similar to  C. semiplumosa, which it further resembles in having a pleated tip on the dactylus of gnathopod 2 inthe female. This structure appears to be unique to these two species, as well as  C. azumai Hirayama & Kikuchi, 1980and  C. littoralis Ariyama, 2005, also from Japan, and  C. thomasi  sp. nov.from Lizard Island.   Distribution.  Australia. Queensland: Lizard and Orpheus Islands (current study).  Japan. Oura and Hikigawa, Wakayama( Ariyama 2005).?  India. Gulf of Mannar: Tuticorin ( Nayar 1966).  Madagascar. Grand Récif de Tuléar ( Ledoyer 1979, 1982). Red Sea. Gulf of Aqaba ( Lyons & Myers 1990). P79275 [412,820,398,424] AM, JDT 12 360 LIZ 3 1 1 P79276 [835,1244,398,424] AM, JDT 12 360 LIZ 5 1 1 JDT 12 360 GCRL 2873, LIZ 5 1 1 P79277 [381,778,437,463] AM, JDT 12 360 LIZ 7 1 1 P79278 [792,1206,437,463] AM, JDT 12 360 LIZ 12 1 1 P79279 AM, JDT 12 360 LIZ 13 4 1 3 [477,907,476,502] JDT 12 360 GCRL 2874, LIZ 13 1 1 P79280 [919,1327,476,502] AM, JDT 12 360 LIZ 14 1 1 P79281 AM, JDT 12 360 OPH 1 3 1 2 P79282 [593,994,514,540] AM 12 360 QLD 11 1 1 P37541 [1007,1408,514,540] AM 12 360 QLD 27 1 1 P70593 AM 12 360 QLD 1622 1 1 P70709 [555,970,553,579] AM 12 360 QLD 1643 1 1 P70735 [981,1410,553,579] AM 12 360 QLD 1643 1 1 P79283 AM 12 360 QLD 1760 1 1 P79284 [555,970,592,618] AM 12 360 QLD 1760 1 1 P71325 [981,1410,592,618] AM 12 360 QLD 1786 1 1 P71434 AM 12 360 QLD 1792 1 1 [198,1019,669,695] Madagascar -23.333334 Grand Recif de Tulear 1256 43.683334 12 360 1 holotype