Abalistes filamentosus, Matsuura & Yoshino, 2004

Matsuura, K. & Yoshino, T., 2004, A New Triggerfish of the Genus Abalistes (Tetraodontiformes: Balistidae) from the Western Pacific, Records of the Australian Museum 56, pp. 189-194 : 190-194

Abalistes filamentosus n.sp.

Fig. 1a

Abalistes stellatus .— Matsuura, 1980, p. 39 (in part); Matsuura, 1984 (in part), pl. 322–I.

Abalistes stellaris .— Matsuura, 1985, pp. 626, 627, 743.

Type material. HOLOTYPE: NSMT-P 65579, 243 mm SL, female, Ryukyu Islands , south coast of Okinawa-jima Island, off Itoman, 17 June 1982, hook and line, T. Yoshino (obtained from local fisherman) . PARATYPES: AMS I.37974-001, 283 mm SL, Timor Sea , 09°57.15'S 129°31.96'E, 65 m depth, trawl, 30–31 March 1995, J. Lloyd (NT Fisheries) ; CSIRO H.1075-02, 216 mm SL, Western Australia, north of Monte Bello Islands , 19°56.2'– 19°57.6'S 115°35.5'– 115°36.8'E, 66–68

m depth, 8 October 1987, demersal trawl, FRV Soela; CSIRO H.2455- 04, 245 mm SL, Western Australia, north of Dampier Archipelago , 19°10.1'– 19°11.8'S 116°47.1'– 116°46.5'E, 180– 166 m depth, 3 October 1989, demersal trawl, W. Whitelaw ( CSIRO) ; CSIRO H.3223-03, 227 mm SL, Western Australia, north of Barrow Island, 20°10.2'– 20°08.7' S 115°15.6'– 115°15.1'E, 10 October 1990, demersal trawl, FRV Southern Surveyor ; HUMZ 38667, 277 mm SL, Ryukyu Islands, south coast of Okinawa-jima Island, off Itoman , 9 March 1974, hook and line, K. Matsuura (obtained from local fisherman) ; HUMZ 38705, 228 mm SL, Ryukyu Islands, south coast of Okinawa-jima Island, off Ohjima , 15 April 1974, hook and line , T. Shimizu (obtained from local fisherman) ; HUMZ 38706, 282 mm SL, Ryukyu Islands, west coast of Okinawajima Island, off Naha , 5 April 1974, hook and line , T. Shimizu (obtained from local fisherman) ; HUMZ 68923, 325 mm SL, Ryukyu Islands, south coast of Okinawa-jima Island, off Itoman , 9 March 1974, K. Matsuura (obtained from local fisherman) ; HUMZ 68924, 281 mm SL, data same as preceding paratype ; HUMZ 68925, 267 mm SL, data same as preceding paratype ; HUMZ 68926, 296 mm SL, data same as preceding paratype ; NSMT-P 49363, 233 mm SL, Ryukyu Islands, Yaeyama Group, Nakano-ogan-jima Island , 24°07.2'N 123°40.1'E, 152 m depth, 14 August 1996, hook and line, K. Yano ; NSMT-P 65580, 317 mm SL, Ryukyu Islands, south coast of Okinawa-jima Island, off Itoman , 18 June 1982, long line , T. Yoshino (obtained from local fisherman) ; URM-P 3320, 295 mm SL, male, data same as holotype ; URM-P 3321, 253 mm SL,!, data same as holotype ; URM-P 3334, 274 mm SL, Ryukyu Islands, south coast of Okinawa-jima Island, off Itoman , 18 June 1982, long line , T. Yoshino (obtained from local fisherman) .

Diagnosis. Dorsal rays III+25–27; anal rays 22–25; pectoral rays 14–15 (usually 14); body scale rows 33–39; head scale rows 25–32 ( Table 1). Upper and lower rays of caudal fin greatly produced in filaments. Cheek with 3 or 4 longitudinal grooves. Proximal part of spinous dorsal fin dark brown; no yellow/pale blue spots or yellow reticulations on the body; ground colour of body dark brown dorsally, mottled with irregular pale markings, becoming white ventrally; cheek brown with greenish tinge.

Description. Body depth 2.7 (2.6–3.2) in SL, head length 2.9 (2.8–3.0) in SL, snout length 4.1 (3.9–4.3) in SL, snout to origin of first dorsal spine 2.6 (2.5–2.7) in SL, snout to origin of anal fin 1.5 (1.5–1.6) in SL, base of soft dorsal fin 3.3 (3.0–3.3) in SL, base of anal fin 3.5 (3.4–3.8) in SL. Body width 1.7 (1.7–2.2) in HL, eye diameter 4.3 (3.5– 5.3) in HL, interorbital width 3.3 (2.9–3.5) in HL, length of gill opening 3.4 (3.2–4.2) in HL, postorbital length 5.3 (4.5– 5.1) in HL, depth of caudal peduncle 8.5 (7.4–10.8) in HL, length of caudal peduncle 2.4 (2.0–2.7) in HL, length of first dorsal-fin spine 1.7 (1.5–2.0) in HL, length of longest soft dorsal-fin ray 2.9 (2.5–3.4) in HL, length of longest anal-fin ray 2.8 (2.8–4.3) in HL, length of middle caudal-fin ray 2.3 (2.2–2.6) in HL, length of pectoral fin 3.0 (2.8–3.5) in HL.

Body relatively elongate, compressed, covered with rhomboidal, plate-like scales as in other balistids; several longitudinal rows of small tubercles on posterior part of body extending forward from caudal-fin base to below posterior part of soft dorsal fin. Dorsal and ventral profiles of head convex. Scales on cheek forming several longitudinal rows, having 3–4 longitudinal grooves between scale rows. Mouth small, terminal, with thin fleshy lips; teeth incisiform, notched on edges; each upper jaw with 4 teeth in outer series and 3 teeth in inner series; each lower jaw with 4 teeth in a single series. Gill opening small, slitlike, slightly oblique, located behind and below eye; a patch of enlarged osseous scales just behind upper end of gill opening. Origin of spinous dorsal fin above pectoral-fin base; first dorsal spine very long and stout, covered anteriorly with tubercles; second dorsal spine about threefourths of first spine; third dorsal spine shorter and more slender than second spine, but prominently projecting above dorsal contour. Soft dorsal and anal fins similar to each other in shape, gently rounded. Pelvic dewlap not developed; encasing scales movable dorsoventrally, attached to posterior end of pelvis. Caudal fin double emarginated, upper and lower rays greatly produced posteriorly into filaments, usually much longer than head length. Caudal peduncle depressed, wider than deep.

Live coloration. Dorsal half of body dark brown mottled with irregular pale markings; 3 white blotches on back, first below base of first dorsal-fin spine, second immediately behind third dorsal-fin spine, and third below middle of soft dorsal fin; cheek greenish brown with 3–4 longitudinal dark brown grooves; ventral half of body pale or white; dorsal half of snout brown; first dorsal fin with large dark brown area on proximal part, pale distally with brown lines; soft dorsal and anal fins pale with 4–5 horizontal wavy brown lines; base of soft dorsal fin dark brown but base of anal fin white; base of caudal fin dark brown dorsally, white ventrally; caudal fin brown or yellowish brown proximally, paler distally with 3–4 vertical wavy brown lines; upper and lower filamentous rays dark brown.

Sexual dimorphism. The holotype and two paratypes ( URM-P 3320 and 3321) were dissected to examine gonads; the holotype and URM-P 3321 are females and URM-P 3320 is male. These specimens do not show sexual dimorphism in shape and colour .

Etymology. The new species is named filamentosus after the filamentous rays in its caudal fin.

Distribution. Abalistes filamentosus is known from the Ryukyu Islands in Japan, the North West Shelf of Australia, and the Timor Sea. The capture records of the type specimens range from 61 to 180 m.

Remarks. The type specimens of A. filamentosus were compared with 46 specimens of A. stellatus . As shown in the Diagnosis, A. filamentosus differs from A. stellatus ( Fig. 1b,c) in having filamentous caudal-fin rays, 3–4 longitudinal grooves on the cheek, and the body without colourful markings. The soft rays of the dorsal and anal fins of A. filamentosus have relatively lower counts with wider ranges than those of A. stellatus ( Table 1). No clear differences are found between two species in proportional measurements ( Table 2).

Richardson (1845) described Balistes vachellii on the basis of a specimen (3.75 inches = 9.5 cm in length) collected from Canton, China, by Rev. George Vachell. Although the type specimen was apparently lost, Richardson stated “No naked spaces exist on the cheek” and “The end of the caudal is even, but the second ray above and below forms a little projecting point”. These characters show that Balistes vachellii is a junior synonym of Abalistes stellatus ( Anonymous, 1798) . Richardson (1846) described Balistes phalreatus from a single specimen (2.25 inches = 5.7 cm SL) collected from the western coasts of Australia (no detailed locality given). His description and the plate (plate 1, figs. 4–5) show that Balistes phalreatus is Abalistes stellatus . Examination of the type specimen confirms that it does not have any grooves on the cheek.

There are complicated nomenclatural problems with the name Abalistes stellatus . Two similar specific names, stellaris and stellatus , have been used for this triggerfish by many authors. The specific name, stellaris , was first given to the species by Bloch & Schneider (1801) based on Lacepède’s (1798) publication. The name stellaris has been applied to this triggerfish by authors such as Herre (1924), Fowler (1928), McCulloch (1929), Smith (1949), Munro (1955), Kyushin et al. (1977), Dor (1984), Matsuura (1984, 1985, 2001), Winterbottom et al. (1989), and Hayashi (2002). The name stellatus has also been applied to this species by authors such as Rüppell (1828), Bleeker (1865 –1869), Günther (1870, 1910), Day (1875), Macleay (1881), Barnard (1927), Whitley (1941), de Beaufort & Briggs (1962), Matsuura (1980), Smith & Heemstra (1986), Allen & Swainston (1988), Randall et al. (1990), Kuiter (1993, 1997), Randall (1995), Myers (1999), and Iwatsuki et al. (2000). Whitley (1941), de Beaufort & Briggs (1962) and Matsuura (1980) showed that Anonymous (1798) first used the Latinized specific name, stellatus , for this species, although the description by Anonymous was based on Lacepède’s (1798) publication. Other authors attribute the authorship to Lacepède (1798). Allen & Swainston (1988) provided an excellent illustration and short account of this species but added to the confusion by applying the authorship of Bloch & Schneider to stellatus . Matsuura (2001) stated that Abalistes stellatus ( Lacepède, 1798) is invalid because Lacepède did not describe the species using a scientific name but only the French vernacular name.

As shown by Matsuura (2001), this taxon was described by Lacepède (1798: 333, 350, pl. 1, fig. 1) under the French vernacular name, Baliste étoilé. Lacepède’s publication was briefly reviewed in the same year by Anonymous in an article in the Allgemeine Literatur-Zeitung (general literature newspaper). Anonymous gave brief descriptions of triggerfishes and filefishes on pages 681 and 682.

Hannelore Paxton kindly provided comments about problems in the article: Anonymous sometimes confused pectoral and pelvic fins, and in most places he did not distinguish between the first (spinous) and second dorsal fins, but he sometimes did. Her translation is given below with our interpretation in square brackets.

…(6) Balistes . This genus has been brought under four subdivisions. a) Balistes with more than one ray in the pectoral [lapsus for pelvic] and dorsal fins.— Vetula ; this species has remarkably beautiful colours. … Stellatus (etoile) [with no accent] from Commerson’s papers/ manuscripts, is a new species, which he has caught around the Isle de France [ Mauritius]. Small spots are distributed over the whole body, 8 or 10 rays [lapsus for spiny elements along the edge of the ventral flap] are in the pelvic fin, without spines on the side of the tail.— Echarpe [with no accent], taken from the same paper/manuscript, characterized particularly by its broad black stripe, running obliquely from the eye to the anal fin, giving it the species name, with 8 to 10 stripes [lapsus for spiny elements along the edge of the pelvic dewlap] in the pelvic fin, 4 rows of spines on the side of the tail; from the seas around the Isle de France. This subdivision includes biaculeatus [neither capitalized nor italicised] L. b) Balistes with more than one ray in the pectoral fin [lapsus for pelvic] and in the dorsal fin [lapsus, not including “first”]. Here we find only the species sinensis [neither capitalized nor italicised] L. c) Balistes with 1 single ray in the pectoral fin [lapsus for pelvic] and more than 1 in the dorsal fin [lapsus not including “first”]. tomentosus, papillosus, etc. d) Balistes with a single ray in the first pectoral and dorsal fins [lapsus, as first presumably should only go with dorsal]. Here are the species monoceros and hispidus of Linne.

It is clear that Anonymous intended to state that Balistes has four subdivisions including Vetula, Stellatus (etoile) and Echarpe, and this shows that the idea of binominal nomenclature was used by Anonymous. Thus, we conclude that Balistes stellatus was proposed and available by Anonymous.

ACKNOWLEDGMENTS. Specimens and collection data were kindly provided by M. McGrouther and S. Reader (AMS), A. Gill (BMNH), J.E. Randall and A. Suzumoto (BPBM), A. Graham and P. Last (CSIRO), H. Imamura (HUMZ), R. Williams (NTM), M. Toda (Okinawa EXPO Park Aquarium), E. Anderson and P. Heemstra (RUSI), P. Hulley (SAM), and P. Ng (ZCR). The German article by Anonymous was kindly translated by H. Paxton. We are grateful to J. Paxton and J. Leis for giving the first author warm hospitality during his stay at AMS. This study was partly supported by a grant to the first author by the Ministry of Education, Culture, Sports and Technology, Japan (no. 13575014).