Phenacoscorpius adenensis Norman, 1939

Motomura, Hiroyuki, Causse, Romain & Struthers, Carl D., 2012, Phenacoscorpius longilineatus, a New Species of Deepwater Scorpionfish from the Southwestern Pacific Ocean and the First Records of Phenacoscorpius adenensis from the Pacific Ocean (Teleostei: Scorpaenidae), Species Diversity 17 (2), pp. 151-160 : 156-159

Phenacoscorpius adenensis Norman, 1939

[New English name: Toothed No-line Scorpionfish]

( Fig. 2 )

Phenacoscorpius adenensis Norman, 1939: 94 , fig. 29 (type locality: Gulf of Aden, Somalia, northwestern Indian Ocean); Smith 1957: 69 (Gulf of Aden); Eschmeyer 1986: 470, fig. 149.17 (off Buffalo River, South Africa); Mandrytsa 1992: 13 ( Socotra Island, Yemen; Walters Shoal, southern Madagascar); Motomura et al. 2011a: 64 (Gulf of Aden; northwestern Madagascar).

Phenacoscorpius sp. 2: Motomura et al. 2011a: 64 ( New Caledonia; Vanuatu).

Holotype. BMNH 1939.5 .24.1545, 79.4 mm SL, Gulf of Aden , Somalia, 274–366 m, John Murray Expedition 1933– 34.

Other material examined. 54 specimens, 17.8– 66.2 mm SL. SOUTH AFRICA: SAIAB 10592 , 58.9 mm SL, off Mbashe Point, South Africa , 32°16′12″S, 29°07′26″E, 25 June 1979 . MADAGASCAR: MNHN 1988-1522 , 66.2 mm SL, 12°46′05″S, 48°10′05″E, 495–500 m, RV Vauban, 15 September 1972 . AUSTRALIA: AMS I. 34465-001, 32.7 mm SL, off entrance to Curalo Lagoon, Twofold Bay , New South Wales, 37°03′12″S, 149°55′24″E, 200 m, J . Lowry and S . Keable, 26 November, 1988; CSIRO H 630-22 , 2 , 40.9–43.4 mm SL, south of Saumarez Reef , Queensland, 22°36′S, 153°50′E, 350 m, FRV Soela , 17 November 1985; CSIRO H 4453-11 , 2 , 24.8–27.6 mm SL, east of Bermagui , New South Wales, 36°30′S, 150°18′E, 214–225 m, FRV Southern Surveyor , 1 December 1996; CSIRO H 4456-01 , 38.6 mm SL, south of Gabo Island , Victoria, 37°52′S, 150°02′E, 213 m, FRV Southern Surveyor , 27 November 1996; CSIRO H 4456-02 , 3 , 30.6–40.5 mm SL, same data as CSIRO H 4456-01; CSIRO H 5329-03 , 2 , 20.0– 23.4 mm SL, south-southeast of Cape Everard, Victoria, 38°10′S, 149°41′E, 259–262 m, FRV Southern Surveyor , 23 April 2000; CSIRO H 5331-04 , 36.2 mm SL, south of Cape Everard , Victoria, 359 m, FRV Southern Surveyor , 22 April 2000; CSIRO H 6047-01 , 51.7 mm SL, Lord Howe Rise, 34°07′58″S, 162°24′25″E, 700 m, RV Tangaroa , 26 May 2003; CSIRO H 6779-01 , 3 , 28.3–40.8 mm SL, south of Gabo Island , Victoria, 37°45′S, 150°00′E, 108– 109 m, FRV Southern Surveyor , 12 December 1996 . NEW CALEDONIA: MNHN 2004-1626 , 35.1 mm SL, Lifou Island , Loyalty Islands, 20°41′10″S, 167°07′44″E, 380 m, RV Alis, 15 February 1989 . VANUATU: MNHN 1998-0034 , 52.9 mm SL, 15°01′01″S, 166°55′59″E, 532–599 m, RV Alis, 9 October 1994; MNHN 1998-0054 , 53.8 mm SL, 16°39′00″S, 168°01′59″E, 469–525 m, RV Alis , 1 October 1994; MNHN 1998-0081 , 26.6 mm SL, 17°46′59″S, 168°48′00″E, 321 m, RV Alis, 28 September 1994; MNHN 2001-2855 , 34.3 mm SL, 17°52′01″S, 168°25′01″E, 300–301 m, RV Alis, 27 September 1994; MNHN 2008-1539 , 56.2 mm SL, 15°42′14″S, 167°02′38″E, 441 m, RV Alis, 17 October 2006; MNHN 2010-0827 , 2 , 59.3 –65.0 mm SL, 15°44′17″S, 167°03′00″E, 603–736 m, RV Alis, 7 October 2006 . FIJI: MNHN 2000- 5678 , 52.1 mm SL, 19°03′S, 178°29′W, 680–723 m, RV Alis, 10 May 1999 . NEW ZEALAND: NMNZ P . 007797, 9, 24.0– 43.3 mm SL, ca. 17 km east of Mayor Island, Bay of Plenty, North Island , 37°20′36″S, 176°28′33″E, 482–550m, RV Tangaroa , 22 January 1979; NMNZ P . 007832, 2, 39.8– 44.3 mm SL, 19 km east-southeast of Mayor Island, Bay of Plenty, North Island , 37°21′18″S, 176°28′51″E, 388–448 m, RV Tangaroa , 22 January 1979; NMNZ P . 007840, 52.5 mm SL, same data as NMNZ P . 7832; NMNZ P. 007882, 29.1 mm SL, 28 km north of Motuhora Island, Bay of Plenty, North Island , 37°36′45″S, 176°59′39″E, 139–179 m, RV Tangaroa , 20 January 1979; NMNZ P . 034493, 2, 17.8–27.3 mm SL, ca. 14 km northeast of Cavalli Island, North Island , 34°46′00″S, 174°05′48″E, 492 m, New Zealand Oceanographic Institute, 10 November 1977; NMNZ P . 038314, 38.3 mm SL, Rumble 3 Submarine Volcano, outer Bay of Plenty, North Island , 35°44′09″S, 178°29′45″E, 202–365 m, RV Tangaroa , 23 May 2001; NMNZ P . 039615, 2, 21.1–24.2 mm SL, southern Norfolk Ridge , 34°37′26″S, 168°57′34″E, 521–539 m, RV Tangaroa , 3 June 2003; NMNZ P . 041324, 44.8 mm SL, Bay of Plenty, North Island , 37°27′47″S, 176°54′50″E, 247– 294 m, RV Tangaroa , 16 November 2004; NMNZ P . 041853, 54.1 mm SL, southeast of Colville Ridge, Bay of Plenty, North Island , 37°21′17″S, 177°06′05″E, 259–294 m, RV Tangaroa , 14 November 2004; NMNZ P . 041854, 48.1 mm SL, same data as NMNZ P . 041853; NMNZ P. 041855, 32.4 mm SL, southeast of Colville Ridge, Bay of Plenty, North Island , 37°28′26″S, 176°54′35″E, 248–256 m, RV Tangaroa , 15 November 2004; NMNZ P . 041857, 30.4 mm SL, Bay of Plenty, North Island , 37°28′04″S, 176°54′53″E, 210–225 m, RV Tangaroa , 15 November 2004; NMNZ P . 041914, 53.1 mm SL, east of Colville Ridge, Bay of Plenty, North Island , 37°28′55″S, 177°12′29″E, 259 m, RV Tangaroa , 11 November 2004; NMNZ P . 041928, 36.7 mm SL, southeast of Colville Ridge, Bay of Plenty, North Island , 37°18′50″S, 177°04′29″E, 466–495 m, RV Tangaroa , 14 November 2004; NMNZ P . 048204, 33.6 mm SL, southern Norfolk Ridge , 34°37′26″S, 168°57′34″E, 521–539 m, RV Tangaroa , 3 June 2003 .

Diagnosis. A species of Indo–Pacific Phenacoscorpius with the following combination of characters: 16–18 (mode 17) pectoral fin rays, middle rays branched in young and adults; 2–8 (mode 3) pored lateral-line scales, last pored scale situated from below second to fifth dorsal-fin spine base; about 50 scale rows in longitudinal series; 17–21 (mode 19) gill rakers; palatine teeth present; nuchal and parietal spines distinct; 3–5 (mode 5) suborbital spines; nape and anterior part of body moderately arched throughout life; relatively short post-nuchal-spine length, 3.2–9.5% (mean 5.7%) of SL; relatively long caudal fin length, 23.4– 30.7% (mean 26.7%) of SL; 5–37 (mode 8) black spots on posterior half of caudal peduncle; 4 distinct saddles on body in preserved specimens; largest recorded specimen 79 mm SL.

Distribution. This species has previously been record- ed from the western Indian Ocean: the Gulf of Aden, Somalia ( Norman 1939; Smith 1957); Socotra Island, Yemen ( Mandrytsa 1992); off Buffalo River, South Africa ( Eschmeyer 1986); Walters Shoal, southern Madagascar ( Mandrytsa 1992); and northwestern Madagascar ( Motomura et al. 2011a). An additional Indian Ocean specimen (SAIAB 10592, 58.9 mm SL, off Mbashe Point, South Africa) was recorded in this study. Fifty-two specimens examined in this study were collected from the southwestern Pacific Ocean: Australia (from Queensland to Victoria, including the Lord Howe Rise), New Caledonia (Loyalty Islands), Vanuatu, Fiji, and northern New Zealand (including the Norfolk Ridge and North Island). They represent the first records of P. adenensis from outside the Indian Ocean. The southwestern Pacific Ocean specimens were collected in depths of 139– 736 m.

Remarks. The southwestern Pacific specimens are herein identified as P. adenensis , a species previously known only from the western Indian Ocean. However, they differ from Indian Ocean specimens in lacking a slit behind the fourth gill arch, but no other differences between the two populations were found during this study. Because the available western Indian Ocean specimens of P. adenensis , including the holotype, were in very poor condition, and all the southwestern Pacific specimens were damaged during capture in deepwater trawls (e.g., the number of scale rows in longitudinal series could not counted in any specimen), more detailed comparisons between these populations, based on specimens in good condition, are required to elucidate their taxonomic status.

The second preopercular spine is usually absent on both sides of the head in P. adenensis . About 26% and 20% of specimens, however, have the second spine on both sides or on only one side of the head, respectively ( Table 2). When present it is reduced, being shorter than the third spine. This condition is also found in P. megalops (see Motomura and Last 2009), but has not been known from any other Indo– Pacific congener: P. eschmeyeri and P. longilineatus always lack the second preopercular spines on both sides of the head (Motomura 2008; Motomura et al. 2012; this study) whereas P. longirostris always has them ( Motomura and Last 2009).

The black blotch on the spinous portion of dorsal fin is rounded in most specimens of P. adenensis , its size being less than the orbit diameter ( Fig. 2A, D ). A few specimens, though, have an elongate blotch that is wider than the orbit diameter, as well as a narrow black band on the basal softrayed portion of the dorsal fin ( Fig. 2C ). These differences may be secondary sexual characteristics, but additional specimens and histological study of the gonads are required to confirm this.

Figures

Fig. 2. Phenacoscorpius adenensis from the southwestern Pacific Ocean. A, MNHN 2001-2855, 34.3mm SL, Vanuatu; B, CSIRO H 6047-01, fresh specimen, 51.7mm SL, Australia; C, NMNZ P. 041914, 53.1mm SL, New Zealand; D, MNHN 2010-0827, 65.0mm SL, Vanuatu.