Colomastix plumosa Ledoyer, 1979

LECROY, SARA E., 2009, Colomastigidae *, Zootaxa 2260 (1), pp. 348-372: 360-363

publication ID

http://doi.org/ 10.11646/zootaxa.2260.1.17

persistent identifier

http://treatment.plazi.org/id/322C8781-045E-FF94-45A5-9FCDDF8C29D9

treatment provided by

Felipe

scientific name

Colomastix plumosa Ledoyer, 1979
status

 

Colomastix plumosa Ledoyer, 1979  

( 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, AM P79275 View Materials ( JDT / LIZ 3)   ; 1 male, AM P79276 View Materials ( JDT / LIZ 5)   ; 1 male, GCRL 2873 View Materials ( JDT / LIZ 5)   ; 1 male, AM P79277 View Materials ( JDT / LIZ 7)   ; 1 male, AM P79278 View Materials ( JDT / LIZ 12)   ; 3 males, 1 female, AM P79279 View Materials ( JDT / LIZ 13)   ; 1 female, GCRL 2874 View Materials ( JDT / LIZ 13)   ; 1 male, AM P79280 View Materials ( JDT / LIZ 14)   ; 2 males, 1 female, AM P79281 View Materials ( JDT / OPH 1)   ; 1 juvenile, AM P79282 View Materials ( QLD 11)   ; 1 juvenile, AM P37541 View Materials ( QLD 27)   ; 1 female, AM P70593 View Materials ( QLD 1622)   ; 1 female, AM P70709 View Materials ( QLD 1643)   ; 1 juvenile, AM P70735 View Materials ( QLD 1643)   ; 1 female, AM P79283 View Materials ( QLD 1760)   ; 1 female, AM P79284 View Materials ( QLD 1760)   ; 1 juvenile, AM P71325 View Materials ( QLD 1786)   ; 1 male, AM P71434 View Materials ( QLD 1792)   .

Type locality. Grand Récif de Tuléar , Madagascar (23°20’S 43°41’E) GoogleMaps   .

Description. Based on 1 male, AM P79278 View Materials (JDT/LIZ 12); 2 males, AM P79281 View Materials (JDT/OPH 1).

Head. Head longer 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 1–2 marginal robust setae short. Antenna 1 peduncle article 1, dorsomedial margin with 2 robust setae. Antenna 2 peduncle 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. Mouthparts other than maxilliped greatly reduced or vestigial. Maxilliped, inner plates completely fused, basal shell not expanded to form a ventral keel.

Pereon. Coxa 1 anterior margin convex, anteroventral angle rounded. Coxae 1–4 without small anteroventral cusp. Coxal gills 2–5 gradually increasing in size, gill 6 smaller than gill 5. Gnathopod 1 vestigial, exact morphology individually variable; propodus without setae. Gnathopod 2 basis 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 3–4 basis not produced anterodistally. Pereopods 3–7 basis slightly expanded. Pereopod 7 propodus, anterior margin without setae.

Pleon. Pleopods 1–3 inner ramus with 4 articles, outer ramus with 4 articles. Pleopod 2 peduncle, anteromedial surface with 3 slender setae. Uropod 1 inner ramus modified, not strongly falcate, expanded proximally, ventral margin straight, tip subtruncate; outer ramus three-fourths length of 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 lanceolate, subequal to outer ramus, ventral margin lacking setae. Telson   broadly 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 View Materials (JDT/OPH 1). Head as long as deep, subequal in length to pereon segment 1 and half of pereon segment 2 combined. Antenna 2 peduncle article 5, dorsal margin without stubby robust setae. Mouthparts other than maxilliped moderately reduced. Oostegite 2 narrowly subovate (length:width ratio 3:1 or greater), slightly longer than basis of gnathopod 2. Gnathopod 1 elongate, slender; propodus with simple apical setae. Gnathopod 2 basis 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 2 peduncle, anteromedial surface without slender setae. Uropod 1 inner ramus unmodified, lanceolate; outer ramus subequal to inner ramus. Uropod 2 both rami, ventral margin densely setose. Uropod 3 inner ramus, ventral margin densely setose.

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 life section of C. processa   sp. nov. for a comparison of the two species).

Host. The sponges Spirastrella insignis Thiele, 1898   and Clathria fasciculata Wilson, 1925   ( Ariyama 2005).

Habitat. Corals, coral rubble, algae ( Caulerpa racemosa J. 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 plumosa   is 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, 1861   from India may 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, 2005   and C. minispinosa Ren, 2006   (possibly a synonym of C. semiplumosa   ). However, uropod 1 of Nayar's material has subequal rami, resembling that of C. plumosa   rather than C. semiplumosa   or C. minispinosa   , both of which have distinctly unequal rami on uropod 1 in the female. The adult male of C. plumosa   was unknown prior to the current study.

Although there are several other species of Colomastix   that have a setose inner ramus on uropod 3 in the female, including the Atlantic species C. bousfieldi LeCroy, 1995   , C. heardi LeCroy, 1995   and C. falcirama LeCroy, 1995   , as well as C. semiplumosa   from Japan and C. minispinosa   from China, C. plumosa   can be distinguished from these and all other known species of Colomastix   by the setose inner and outer rami of uropod 2 in the female and by the simple, subtruncate tip of the inner ramus of uropod 1 in the 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 in the female. This structure appears to be unique to these two species, as well as C. azumai Hirayama & Kikuchi, 1980   and 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).

AM

Australian Museum

Kingdom

Animalia

Phylum

Arthropoda

Class

Malacostraca

Order

Amphipoda

Family

Colomastigidae

Genus

Colomastix

Loc

Colomastix plumosa Ledoyer, 1979

LECROY, SARA E. 2009
2009
Loc

Colomastix plumosa

Ariyama, H. 2005: 27
Lyons, J. & Myers, A. A. 1990: 1220
Ledoyer, M. 1982: 158
Ledoyer, M. 1979: 26
1979
Loc

Colomastix pusilla

Nayar, K. N. 1966: 145
Grube, A. E. 1861: 137
1966