Hipposcorpaena filamentosa Fowler, 1938

Wibowo, Kunto & Motomura, Hiroyuki, 2021, Distributional range extension of a rare scorpionfish, Hipposcorpaena filamentosa (Actinopterygii, Scorpaeniformes, Scorpaenidae), Acta Ichthyologica et Piscatoria 51 (1), pp. 23-28 : 23

Hipposcorpaena filamentosa Fowler, 1938

[Standard English name (Australia): Filamentous Scorpionfish; new standard Japanese name: Itohiki-kasago] Figs 1 , 2 , 3

Material examined.

2 specimens. NMV A 29729 -041, 29.5 mm SL, Ashmore Islands , Western Australia, 12°26′42″-58″S, 123°36′03″-35″E, 95 m, beam trawl, RV Southern Surveyor, 7 July 2007 ; SAIAB 57321, 17.2 mm SL, Aliwal Shoal off Scottburgh, KwaZulu-Natal, South Africa, 30°18′S, 30°48′E, 34-36 m, A. Bentley et al., 9 February 1998 .

Description.

Meristics and morphometrics of the specimens are shown in Table 1 . Dorsal fin with 11 or 12 spines and 9 or 10 soft rays; all rays, except posteriormost, divided into 2 at base, unbranched; 1st spine length less than half that of 2nd spine; 2nd or 3rd spine longest, length much greater than upper-jaw length; 2nd to 10th (3rd to 10th in small specimen) spines progressively shorter; interspinous membranes of adjacent dorsal-fin spines reaching tips of posterior spines, except 2nd, 11th, and 12th (2nd and 11th in small specimen) spines; 5th ray longest (broken in small specimen); 5th to last soft rays progressively shortening; intersoft-rayed membrane reaching tips of posterior rays; posterior branch of last soft ray joined by membrane to caudal peduncle for less than half its length. Anal fin with 2 spines and 6 soft rays; all rays, except posteriormost, divided into 2 at base, unbranched; 1st spine 2.6 in 2nd spine; 1st to 4th soft rays progressively lengthening, 4th longer than longest dorsal-fin soft ray; 4th to 6th soft rays progressively shortening; posterior branch of last soft ray joined by membrane to caudal peduncle for less than one-sixth its length; membranes between rays weakly notched. Pectoral fin with 14 rays, all rays unbranched; 2nd to 7th rays progressively shortening (about equal length in small specimen); 9th ray longest, length slightly greater than head length; 9th to lowermost rays progressively shortening; membranes between 2nd and 7th rays reaching tip of each ray; membranes between 8th and lowermost rays strongly notched, membranes between 9th and lowermost rays extending to one-third to half (half to two-thirds in small specimen) length of each upper adjacent ray; lower 7 rays filamentous. Pelvic fin with 1 spine and 5 soft rays, 1st to 3rd soft rays branched, remaining rays unbranched; 2nd soft ray longest, longer than upper jaw length. Caudal fin with 14 rays, all unbranched; 8th (counted from above) ray longest, slightly greater (shorter in small specimen) than body depth.

Longitudinal scale rows 53 (not obvious in small specimen); pored lateral-line scales 22 (counted from right side in large specimen); scale rows between origin of last dorsal-fin spine and lateral line 8 (not obvious in small specimen). Gill rakers on upper limb 5 or 6, on lower limb 14-16, including 5 or 6 rakers on hypobranchial; gill rakers short, spinous, longest raker on 1st gill arch less than one-fourth length of longest gill filament; 4th gill slit closed by membrane.

Body and head strongly compressed, head width less than greatest body width. Body moderately deep, deepest at origin of 2nd dorsal-fin spine. Head large, length greater than body depth. Posterior lacrimal spine with rounded tentacle, length approximately equal to orbit diameter (slightly greater than pupil diameter in small specimen). Large tentacle on supraocular spine, its length greater than orbit diameter. Pair of tentacles projecting from anterior surface of lip at symphysis of upper jaw. Tentacle on posterior margin of anterior nostril, length less than posterior lacrimal tentacle. Small tentacle on cheek (absent in small specimen). Three to four tentacles along preopercular margin; lowermost largest, elliptical, length less than pupil diameter; uppermost slender, on uppermost preopercular spine (absent in large specimen). Two obvious tentacles on each side of ventral surface of mandible, 1st simple, long, slender, located between 1st and 2nd dentary pores; 2nd larger, on posterior margin of dentary. Few tentacles on lateral-line scales. Small elliptical fleshy tentacles on outer part of eye membrane. Few tiny tentacles on spinous portion of dorsal fin and 7 uppermost rays of pectoral fin (absent in large specimen).

Numerous small papillae covering head and body. Posterior nostril opening upward, diameter about equal to anterior nostril, not visible laterally. Two distinct sensory pores, 1st anterior to anterior nostril, 2nd between anterior and posterior nostrils (not obvious in small specimen). Underside of dentary with 3 small sensory pores on each side, small pore behind nodular portion of lower jaw on each side. No scales on surface of head, including opercle, interorbital space, and occipital pit. Body covered with small cycloid scales, not extending onto fins. Embedded scales covering pectoral-fin base (not obvious in small specimen). No scales on ventral body surface.

Mouth oblique, forming an angle of ca. 30 degrees to horizontal axis of head and body. Posterior margin of maxilla not reaching (just reaching in small specimen) vertical level of anterior margin of orbit. Lateral surface of maxilla smooth, without ridges. Lower jaw with thickened symphysial portion fitting into shallow median depression of upper jaw when mouth completely closed. Width of symphysial gap separating premaxillary teeth bands broader than width of each band. Upper and lower jaws with approximately equal-width bands of villiform teeth; majority of upper- and lower-jaw teeth of similar length. Vomer with narrow patch of villiform teeth. No teeth on palatine.

Dorsal profile of snout strongly curved, initially convex, thereafter deeply concave (steep anterior to orbit, but slightly concave behind ascending process of premaxilla in small specimen). Nasal spine simple, small, directed dorsoposteriorly (indistinct in small specimen). Posterior margin of ascending process of premaxilla not reaching vertical level of posterior nostril. Interorbital ridges present, low, beginning level with supraocular spine and ending at base of postocular spine. Interorbital space relatively narrow, deep (broader and shallower in small specimen), forming V-shape in anterior view. Preocular spine simple (not obvious in small specimen), directed upward, tip extending slightly beyond horizontal line through upper margin of pupil in lateral view. Supraocular spine simple, located considerably anterior to vertical midline of eye. Postocular spines simple, triangular in lateral view. Tympanic spine simple, small, directed upward. No coronal spines. Occipital pit shallow, behind distinct transverse ridge, curved posteriorly in dorsal view. Parietal and nuchal spines well developed, joined at base. Sphenotic with 1 small spine. Postorbital with 4 short, small, pointed spines (smooth without ridge or spines in small specimen). Pterotic spine simple, small, pointed, with narrow base, located just above uppermost end of preopercular ridge. Posttemporal spine simple, pointed, small, directed dorsoposteriorly; no upper posttemporal spine. Supracleithral spine simple, pointed.

Lateral surface of lacrimal with 5 low ridges radiating from center, but lacking spines; uppermost end of upwardly directed ridge with bump directly below posterior nostril; anterior end of forward ridge and lower end of downward ridge not projecting over upper lip. Suborbital ridge very low, with 4 small spines in large specimen (1st spine located above posterior margin of maxilla, 2nd just below anterior margin of orbit, 3rd and 4th adjoining, below posterior part of orbit); 3 spines in small specimen (1st spine just above tip of posterior lacrimal spine; 2nd and 3rd spines adjoining, below posterior part of orbit). Broad space between ventral margin of orbit and suborbital ridge. Suborbital pit shallow, front rimmed by an oblique low lacrimal ridge. Preopercle with 4 blunt spines; uppermost spine largest with low median ridge; 2nd with low median ridge; 3rd and 4th spines without median ridge. No supplemental preopercular spine. Upper and lower opercular spines simple, each with median ridge; lower spine almost horizontal.

Origin of 1st dorsal-fin spine above posttemporal spine base. Posterior margin of opercular membrane and upper end of pectoral-fin base extending slightly beyond vertical from base of 3rd dorsal-fin spine. Posterior tip of longest pectoral-fin ray extending beyond vertical from posterior end of anal-fin base. Origin of pelvic fin slightly anterior to base of pectoral fin; posterior tip of depressed pelvic fin extending slightly beyond anus (extending to 2nd anal-fin spine base in small specimen). Origin of 1st anal-fin spine slightly posterior to origin of last dorsal-fin spine.

Color of fresh specimens

(Fig. 1A, C ). Body red-brown with whitish blotches surrounding pectoral-fin base. Snout whitish, posterior half of head red with distinct small black or purplish spots below orbit. Dorsal fin red, posterior of spinous and soft ray portions with broad white band or whitish irregular markings or spots, basal area with 2-4 whitish spots (width slightly larger than pupil diameter). Pelvic fin blackish or reddish. Anal fin reddish basally, blackish distally. Caudal fin reddish posteriorly, whitish anteriorly, with black spots on lower rays (3 spots between 10th and 12th rays in large specimen, 4 on four lowermost rays in small specimen).

Color of preserved specimens

(Fig. 1B, D ). Head and body uniformly pale yellowish. Dorsal fin translucent. Pelvic fin translucent brownish. Anal fin translucent with brownish margin. Caudal fin translucent, with obvious dark brown spots on lower basal region.

Color in life.

In general, similar to color when fresh (see Allen and Erdmann 2012: 224, unnumbered fig.; this study: Fig. 2 ).

Distribution.

Hipposcorpaena filamentosa is widely distributed in the Indo-West Pacific (Fig. 3 ), being recorded from South Africa (Aliwal Shoal off Scottburgh), Japan (Kashiwa-jima Island), and Australia (Ashmore Islands), as well as previously from the Philippines (Luzon, Mindanao, and Sulu islands) ( Fowler 1938; Motomura and Senou 2005), Indonesia (Lembeh Strait and Bali), and Papua New Guinea (Milne Bay Province) ( Allen and Erdmann 2012). Previously reported from depths of 10-51 m ( Fowler 1938; Motomura and Senou 2005; Allen and Erdmann 2012), the South African and Australian specimens were collected in depths of 34-36 m and 95 m, respectively, and the Japanese underwater photograph was taken at 45 m.

Figures

Figure 1. Photographs of Hipposcorpaena filamentosa. (A) fresh and (B) preserved specimens of SAIAB 57321, 17.2 mm SL, South Africa, and (C) fresh and (D) preserved specimens of NMV A 29729 - 041, 29.5 mm SL, Australia. Fresh South African and Australian specimen photos by P. Heemstra and M. Gomon, respectively and also available on the websites of http: // fishwatch. tripod. com / REPORTS / FW _ final _ 2006 _ files / page 0002. htm and https: // fishesofaustralia. net. au / home / species / 2673, respectively.

Figure 2. Underwater photograph of Hipposcorpaena filamentosa, taken at Kashiwa-jima Island, Kochi, Japan, at a depth of 45 m on 10 May 2007 (Photo by K. Matsuno).

Figure 3. Distributional records of Hipposcorpaena filamentosa, based on previous studies (circles) and this study (stars). Closed and open symbols indicate specimen- and underwater photograph-based records, respectively.