TRICHONOTUS ELEGANS - (SHIMADA & YOSHINO, 1984)
Picture courtesy of: Alain Daoulas
Actinopterygii (Gigaclass) > Actinopteri (Class) > Teleostei (Subclass) > Gobiiformes (Order) > Trichonotoidei (Suborder) > Trichonotidae (Family) > Trichonotus (Genus)
Plongeur de sable élégant, Elegant sand diver, Long-rayed sand-diver, Ryûgû-beraginpo, リュウグウベラギンポ, 美丽毛背鱼,
Description
Dorsal spines (total): 3; Dorsal soft rays (total): 43-45; Anal spine: 1; Anal soft rays: 39-42; Pectoral fin rays: 12-14; Pelvic fin rays: I, 5; Branchiostegal rays: 7 (6+1); Lateral line scales: 56-59; Vertebrae: 53-56. Body elongate, cylindrical and gradually compressed backward. Snout pointed. Mouth large, slightly oblique; Maxilla extending to or slightly beyond a vertical at anterior edge of pupil; Lower jaw slightly projecting beyond the upper. Lower jaw with a single row of canine-like teeth and two or three pairs of enlarged teeth at near symphysis. Upper jaw with a single row of canine-like teeth, broadening to two rows posteriorly, and several pairs of enlarged teeth on anterior sides. Similar teeth in a row on palatines,and on vomer in an angular band. Tongue slender, tip rounded. A fold of skin covers margin of eye except for posterior side; eye with about 15 hairlike iris lappets radiating across pupil from dorsal side of iris. Interorbital narrow, about a half of eye diameter. Nostrils: 2, anterior nostril with a slightly elevated fleshy rim. Gill membrane free from isthmus. Gill rakers blade-like on outer face of first gill arch, most of them with several spinules; Those on inner face of first gill arch with a row of small branchial teeth bearing spines. First to 6th branchiostegal rays on ceratohyal and 7th one on epihyal. Glossohyal narrow and elongate. A broad predorsal bone between first and second neural spines; First dorsal pterygiophore inserted between 4th and 5th neural spines; 3 or 4 free pterygiophores between 5th and 8th neural spines. First anal pterygiophore opposite below 15th or 16th vertebrae. Infraorbital canal ending close to supraorbital canal anteriorly. Dorsal spines flexible and filamentous, 2nd or 3rd longest in male, not prolonged in female. Anal spine flexible and shorter than following rays in both sexes. In male, caudal fin lanceolate, asymmetrical; 8th ray longest and filamentous in male. In female the fin rounded. Pelvic fin inserted slightly in advance of pectoral, long and fan-like in male, short in female; Longest (4th) ray extending beyond anus in male, not reaching to anus, approximately same length as pectoral fin in female. Scales cycloid; Anterior half of body without scales except for along dorsal and anal fin bases, and lateral line of body. Head naked except for several scales on occiput, and a row of three or four embedded scales on postero-ventral margin or eye. Lateral line complete and almost straight along midline of body. Max. length: 18.0 cm SL. Depth range: 10 - 40 m.
Color
Male: body pale brown, whitish below. An elongate black blotch above pectoral base with a bluish-white margin. A series of bluish-white ocelli with faded dark rims along lateral midline from uppermost edge of opercle to posterior third of body and several similar ocelli on posterior part of head. Nine yellowish-orange spots super imposed on the series of bluish-white ocelli of body; Each anterior five with a small black central spot. Seventeen bluish-white saddle bands with faded dark rims along dorsal base from nape to last dorsal ray. Thread-like dorsal spines with yellowish-orange and whitish bars alternatively; Eeach yellowish-orange bar with dark borders at both ends. Behind 7th dorsal ray, several yellowish-orange spots on each ray and several similar spots on upper half of caudal fin along the rays; Dorsal fin membranes between first spine and first ray with irregular large black and gray patches; Margin of pelvic fin and lower fourth of caudal fin slightly dark, other fins transparent.
Female: body pale brown, whitish below. Three longitudinal series of black spots on upper half of body from posterior part of head to base of caudal fin; Ventral series consisting of small black spots; Middle series stripe-like because spots are almost continuously arranged; Dorsal series consisting of spots. Lower half of head pale, upper half pale brown with small scattered dark spots. Each dorsal ray with one to several dark spots, those on tip of rays conspicuous. Each dorsal membrane between first spine and first ray with a black blotch; Largest one between second and third spines. Upper half of caudal fin with several pale dark spots along rays; Other fins transparent.
Etymology
Trichonotus: from Ancient Greek, thríx = hair or ray + from Ancient Greek, nôton = the back or the dorsal aspect of the thorax in some species. Referring to elongate or filamentous anterior dorsal fin rays of Trichonotus setiger males.
elegans: from Latin, elegans = fine, elegant, handsome. Referring to its “elegant body shape and undulating swimming motion”.
Original description: Trichonotus elegans Shimada & Yoshino, 1984 - Type locality: South-southeast of Hatoma Island, Yaeyama Islands, Okinawa Prefecture, Japan, 24°28'N, 123°49'E, depth about 20 meters.
Distribution
Indo-West Pacific: Maldive Islands east to Micronesia and Fiji, north to Ryukyu Islands (Japan), south to Papua New Guinea, Australia and New Caledonia.
Biology
Found in coastal reef slopes and deep outer reef lagoons in current channels. Usually in large groups with several large males. Found hovering above sandy slopes. Usually forms a harem of one male-phase fish and about a dozen female-phase fish. Normally buried when no current is running.
Similar species
Actinopterygii (Gigaclass) > Actinopteri (Class) > Teleostei (Subclass) > Gobiiformes (Order) > Trichonotoidei (Suborder) > Trichonotidae (Family) > Trichonotus (Genus)
Plongeur de sable élégant, Elegant sand diver, Long-rayed sand-diver, Ryûgû-beraginpo, リュウグウベラギンポ, 美丽毛背鱼,
Description
Dorsal spines (total): 3; Dorsal soft rays (total): 43-45; Anal spine: 1; Anal soft rays: 39-42; Pectoral fin rays: 12-14; Pelvic fin rays: I, 5; Branchiostegal rays: 7 (6+1); Lateral line scales: 56-59; Vertebrae: 53-56. Body elongate, cylindrical and gradually compressed backward. Snout pointed. Mouth large, slightly oblique; Maxilla extending to or slightly beyond a vertical at anterior edge of pupil; Lower jaw slightly projecting beyond the upper. Lower jaw with a single row of canine-like teeth and two or three pairs of enlarged teeth at near symphysis. Upper jaw with a single row of canine-like teeth, broadening to two rows posteriorly, and several pairs of enlarged teeth on anterior sides. Similar teeth in a row on palatines,and on vomer in an angular band. Tongue slender, tip rounded. A fold of skin covers margin of eye except for posterior side; eye with about 15 hairlike iris lappets radiating across pupil from dorsal side of iris. Interorbital narrow, about a half of eye diameter. Nostrils: 2, anterior nostril with a slightly elevated fleshy rim. Gill membrane free from isthmus. Gill rakers blade-like on outer face of first gill arch, most of them with several spinules; Those on inner face of first gill arch with a row of small branchial teeth bearing spines. First to 6th branchiostegal rays on ceratohyal and 7th one on epihyal. Glossohyal narrow and elongate. A broad predorsal bone between first and second neural spines; First dorsal pterygiophore inserted between 4th and 5th neural spines; 3 or 4 free pterygiophores between 5th and 8th neural spines. First anal pterygiophore opposite below 15th or 16th vertebrae. Infraorbital canal ending close to supraorbital canal anteriorly. Dorsal spines flexible and filamentous, 2nd or 3rd longest in male, not prolonged in female. Anal spine flexible and shorter than following rays in both sexes. In male, caudal fin lanceolate, asymmetrical; 8th ray longest and filamentous in male. In female the fin rounded. Pelvic fin inserted slightly in advance of pectoral, long and fan-like in male, short in female; Longest (4th) ray extending beyond anus in male, not reaching to anus, approximately same length as pectoral fin in female. Scales cycloid; Anterior half of body without scales except for along dorsal and anal fin bases, and lateral line of body. Head naked except for several scales on occiput, and a row of three or four embedded scales on postero-ventral margin or eye. Lateral line complete and almost straight along midline of body. Max. length: 18.0 cm SL. Depth range: 10 - 40 m.
Color
Male: body pale brown, whitish below. An elongate black blotch above pectoral base with a bluish-white margin. A series of bluish-white ocelli with faded dark rims along lateral midline from uppermost edge of opercle to posterior third of body and several similar ocelli on posterior part of head. Nine yellowish-orange spots super imposed on the series of bluish-white ocelli of body; Each anterior five with a small black central spot. Seventeen bluish-white saddle bands with faded dark rims along dorsal base from nape to last dorsal ray. Thread-like dorsal spines with yellowish-orange and whitish bars alternatively; Eeach yellowish-orange bar with dark borders at both ends. Behind 7th dorsal ray, several yellowish-orange spots on each ray and several similar spots on upper half of caudal fin along the rays; Dorsal fin membranes between first spine and first ray with irregular large black and gray patches; Margin of pelvic fin and lower fourth of caudal fin slightly dark, other fins transparent.
Female: body pale brown, whitish below. Three longitudinal series of black spots on upper half of body from posterior part of head to base of caudal fin; Ventral series consisting of small black spots; Middle series stripe-like because spots are almost continuously arranged; Dorsal series consisting of spots. Lower half of head pale, upper half pale brown with small scattered dark spots. Each dorsal ray with one to several dark spots, those on tip of rays conspicuous. Each dorsal membrane between first spine and first ray with a black blotch; Largest one between second and third spines. Upper half of caudal fin with several pale dark spots along rays; Other fins transparent.
Etymology
Trichonotus: from Ancient Greek, thríx = hair or ray + from Ancient Greek, nôton = the back or the dorsal aspect of the thorax in some species. Referring to elongate or filamentous anterior dorsal fin rays of Trichonotus setiger males.
elegans: from Latin, elegans = fine, elegant, handsome. Referring to its “elegant body shape and undulating swimming motion”.
Original description: Trichonotus elegans Shimada & Yoshino, 1984 - Type locality: South-southeast of Hatoma Island, Yaeyama Islands, Okinawa Prefecture, Japan, 24°28'N, 123°49'E, depth about 20 meters.
Distribution
Indo-West Pacific: Maldive Islands east to Micronesia and Fiji, north to Ryukyu Islands (Japan), south to Papua New Guinea, Australia and New Caledonia.
Biology
Found in coastal reef slopes and deep outer reef lagoons in current channels. Usually in large groups with several large males. Found hovering above sandy slopes. Usually forms a harem of one male-phase fish and about a dozen female-phase fish. Normally buried when no current is running.
Similar species
- Trichonotus blochii (Castelnau, 1875) - Reported from Northern Australia: Western Australia to Queensland, Australia. Dorsal fin soft rays: 43-46; Anal fin soft rays: 39-41; Lateral line scales: 57-60; Gill rakers: 4-6 + 17-21; Vertebrae: 55; Infraorbital and supraorbital canals separated anterior to eye; Elongated dorsal fin spines: 4-6 in males; Caudal fin with Two black stripes in males.
- Trichonotus filamentosus (Steindachner, 1867) - Reported from Western Pacific.
- Trichonotus halstead (Clark & Pohle, 1996) - Reported from Western Pacific: Sulawesi (Indonesia) and Papua New Guinea. Trichonotus halstead is similar to Trichonotus setiger but has a beautifully colored dorsal fin and no free pterygiophores under dorsal fin.
- Trichonotus setiger (Bloch & Schneider, 1801) - Reported from New Caledonia - Link to the species (here).