Variation in habitat and color of the Hawaiian scorpionfish Sebastapistes coniorta

Transcription

1 aqua, International Journal of Ichthyology Variation in habitat and color of the Hawaiian scorpionfish Sebastapistes coniorta John E. Randall and John L. Earle Bishop Museum, 1525 Bernice St., Honolulu, HI , USA. Received: 08 October 2008 Accepted: 21 January 2009 Abstract Small scorpionfish specimens found in two old Bishop Museum lots of Sebastapistes ballieui from the Hawaiian Islands and suspected of being the non-hawaiian S. cyanostigma, are re-identified as the Hawaiian endemic S. coniorta. The wide-ranging Indo-Pacific S. cyanostigma is distinguished from S. coniorta in having numerous white dots rather than small dark brown spots, and in the structure of the double suborbital ridge (merging to a single ridge posteriorly in S. cyanostigma). Unusual variation in the habitat and life color of S. coniorta is documented. Zusammenfassung Kleine Skorpionsfischexemplare in zwei alten Sammlungen des Bishop Museum mit Sebastapistes ballieui von den Hawaii-Inseln, die man dem nicht-hawaiischen S. cyanostigma zugeordnet hatte, wurden neu als S. coniorta bestimmt, der auf Hawaii endemisch ist. Die Art S. cyanostigma, die im indo-pazifischen Raum weit verbreitet ist, unterscheidet sich durch zahlreiche weiße Flecken von S. coniorta, deren Vertreter kleine dunkelbraune Flecken aufweisen, sowie durch einen doppelten suborbitalen Grat (S. cyanostigma hat einen einfachen Grat im hinteren Bereich). Dokumentiert wird die ungewöhnliche Variabilität von S. coniorta nach Habitat und Lebendfärbung. Résumé De petits spécimens de poissons-scorpions, trouvés au Bishop Museum dans deux vieux lots de Sebastapistes ballieui des Îles Hawaï et supposés être S. cyanostigma, qui n est pas hawaïen, sont réidentifiés en tant que S. coniorta, endémique d Hawaï. S. cyanostigma, largement répandu dans l Indo-Pacifique, se distingue de S. coniorta par la présence de nombreuses taches blanches au lieu de petites taches brun foncé et par la structure de la double série suborbitale (se fusionnant postérieurement en une seule chez S. cyanostigma). Une variation inhabituelle dans l habitat et la couleur in vivo de S. coniorta est documentée. Sommario Alcuni piccoli esemplari di pesce scorpione, rinvenuti presso il Bishop Museum in due vecchi lotti della specie Sebastapistes ballieui delle Isole Hawaii e sospettati di appartenere alla specie non hawaiana S. cyanostigma, sono stati riconosciuti invece come esemplari della specie hawaiana endemica S. coniorta. La specie indopacifica S. cyanostigma si distingue da S. coniorta per avere numerosi puntini bianchi anziché piccole macchie di colore bruno scuro e per la struttura della doppia cresta suborbitale (in S. cyanostigma si unisce posteriormente in una singola cresta). Insolite variazioni nell habitat e nella colorazione nativa di S. coniorta sono altresì documentate. INTRODUCTION The fishes of the family Scorpaenidae are aptly named scorpionfishes for the venomous fin spines of most of the species. They are bottom-dwelling and are generally well camouflaged by their color pattern and dermal appendages. Gosline & Brock (1960) reported 18 species of scorpionfishes in the Hawaiian Islands. Eschmeyer & Randall (1975) added two new species and four new records in a review of the Hawaiian species of the family. Randall & Poss (2002) reclassified Scorpaenopsis fowleri (Pietschmann, 1934) to the genus Sebastapistes Gill, 1877, thus adding a fourth species to the genus for the Hawaiian Islands. Variation in the endemic Hawaiian Sebastapistes coniorta (Jenkins, 1903) gave rise to the suspicion that it might consist of more than one species. Randall (2007) included species accounts, illustrations, and a key to the 25 species of scorpionfishes that occur in less than 200 m in the Hawaiian Islands. In the introduction to the family on p. 167, he discussed two old lots of scorpionfishes in the Bernice P. Bishop Museum, Honolulu (BPBM) that had been identified as Scorpaena ballieui Sauvage, One lot of three specimens was collected by W. H. Bryan in July 1914 at Moloka i. The largest of the three specimens is Sebastapistes ballieui, but the two smaller ones were re-identified as S. cyanostigma (Bleeker, 1856), a species not known from the 61 aqua vol. 15 no April 2009

2 Variation in habitat and color of the Hawaiian scorpionfish Sebastapistes coniorta Hawaiian Islands. The second lot has a locality of Honolulu and a date as likely 1920 s. It also contains three specimens, two of S. ballieui and one reidentified as S. cyanostigma. Because S. cyanostigma is a common shallow-water species at other islands of Oceania and is unknown in the well-collected Hawaiian Islands, and because specimens of scorpionfishes from other islands of the Pacific were being cataloged at the same time at the Bishop Museum, Randall (2007) suggested that the collections had been mixed, and the ones he identified as S. cyanostigma were not of Hawaiian origin. Although no longer showing any trace of small dark spots, reexamination of these old specimens reveals that they are the endemic Hawaiian Sebastapistes coniorta Jenkins, 1903, a close relative of the wide-ranging Indo-Pacific S. cyanostigma. Recent material of S. coniorta reveals that it is more variable in color and habitat than previously known. Based on this material, we provide here a diagnosis of Sebastapistes coniorta, its distinction from S. cyanostigma, and discussion of its variability and habitat. Lengths of specimens are given as standard length (SL) from the front of the snout to the base of the caudal fin. Sebastapistes coniorta Jenkins, 1903 (Figs 3, 5-9) Sebastapistes coniorta Jenkins, 1903: 493, fig. 38 (type locality, Honolulu). Material examined: HAWAIIAN ISLANDS: Hawai i, BPBM 37270, 2: mm. Maui, BPBM 13799, 11: mm (specimens dried). Moloka i, BPBM 39102, 2: mm. O ahu, BPBM 4354, 61 mm; BPBM 4357, 2: mm; BPBM 4359, 3: mm; BPBM 4362, 3: mm; BPBM 4363, 75 mm; BPBM 4364, 25 mm; BPBM 5277, 2: mm; BPBM 5308, 2: mm; BPBM 6464, 4: mm; BPBM 7884, 4: mm; BPBM 8587, 5: mm; BPBM 9786, 3: mm; BPBM 9987, 36 mm; BPBM 12285, 18 mm; BPBM 13796, 2: mm; BPBM 22679, 8: mm; BPBM 28137, 42 mm; BPBM 40920, 4: mm. Pearl and Hermes Reef, BPBM 4362, 3: mm. Midway, BPBM 34772, 2: mm; BPBM 34843, 5: mm. JOHNSTON ISLAND: BPBM 13798, 51 mm. Diagnosis: Dorsal rays XII,9; anal rays III,5; pectoral rays 16; lateral-line scales 25-26; longitudinal scale series 49-50; gill rakers ; palatine teeth present; no coronal spines; a double ridge below eye, with a small retrorse spine at posterior end of each ridge; opercle scaled, with no ridge anterior to lower opercular spine; lacrimal bone with two lower spines that extend to dorsal part of upper lip, one projecting Fig. 1. Sebastapistes cyanostigma, BPBM 18348, 45 mm SL, northern Red Sea. Photo by J. E. Randall. aqua vol. 15 no April

3 John E. Randall and John L. Earle Fig. 2. Sebastapistes cyanostigma, Kiritimati (Christmas Island), Line Islands. Underwater photo by J. E. Randall. Fig. 3. Sebastapistes coniorta in Pocillopora meandrina, Kona, Hawai i. Underwater photo by J. E. Randall. 63 aqua vol. 15 no April 2009

4 Variation in habitat and color of the Hawaiian scorpionfish Sebastapistes coniorta nearly anteriorly, the other ventroposteriorly (a small middle spine present or absent); supraorbital tentacle absent; most common color pattern dark brown with large lighter brown blotches and numerous small black spots on body, postorbital head, and cheek, the spots visible mainly in lighter brown blotches; fins translucent pale gray-brown except for black spots in dorsal fin (usually only basally) and pale margin of soft portion of median fins (may be red in life); largest specimen, 77 mm SL. Discussion: Fowler (1928: 287) placed Sebastapistes coniorta in the synonymy of S. albobrunnea (Günther, 1874), type locality Palau. The name S. albobrunnea was used by many authors until William N. Eschmeyer (unpublished manuscript on Sebastapistes) showed that it is a synonym of S. cyanostigma (Bleeker, 1856), type locality, Molucca Islands, Indonesia. Schultz in Schultz et al. (1966: 28) correctly regarded S. coniorta as a Hawaiian endemic, noting the presence of small brown spots on the body as the only distinguishing feature. Both Sebastapistes coniorta and S. cyanostigma have a double suborbital ridge. We confirm the difference that Eschmeyer found in this feature: the two ridges merge in S. cyanostigma, ending in a small spine, whereas each of the ridges terminates in a spine in S. coniorta, one below the posterior end of the orbit, and the other at the preopercular margin. Sebastapistes cyanostigma is distributed from the Red Sea (Fig. 1), where it was named Scorpaena aqabae by Fowler & Steinitz (1956), south on the east coast of Africa to Port Alfred (type locality of Scorpaena kowiensis Smith, 1935), east to the islands of Micronesia (Myers, 1999: 100, pl. 27 F), Samoa Islands, and the Line Islands (Fig. 2). It ranges in the western Pacific from the Ryukyu Islands to the Great Barrier Reef. In addition to lacking small dark brown spots, it differs in color from S. coniorta in being densely dotted with white. Sebastapistes coniorta occurs throughout the Hawaiian Archipelago, and Gosline (1955: 462) reported it from Johnston Island. Myers (1999: 100) included Wake Island and the Line Islands as localities for S. coniorta, probably from records in Fowler (1928: 287) as Scorpaena albobrunnea and S. asperella Bennett, Fowler also mistakenly included Fig. 4. Southeast shore of O ahu at Lana i Lookout, indicating location of surge-zone cave with Sebastapistes coniorta. aqua vol. 15 no April

5 John E. Randall and John L. Earle S. galactacma Jenkins, 1903 (type locality, Honolulu) as a synonym of S. albobrunnea, but it is a valid species, wide-ranging in the Pacific. Scorpaena asperella Bennett, 1828 is the oldest name for a scorpionfish from the Hawaiian Islands. As noted by Günther (1873: 80), the type specimen is lost. Bennett s description is too brief to be identified as any Hawaiian species of Scorpaenidae (Gosline, 1955: 461; Eschmeyer & Randall, 1975: 319). Sebastapistes cyanostigma is typically found among branches of live coral, especially species of Pocillopora. Sebastapistes coniorta may be seen in Pocillopora meandrina (Fig. 3), but it also occurs in other habitats, including tidepools. Eschmeyer & Randall (1975: 317) gave the depth range from near shore to 24.5 m. The second author discovered an unusual habitat of S. coniorta, caves in shallow water subject to strong wave action. He collected three specimens from a cave off the Lana i Lookout on O ahu (Fig. 4) at a depth of 4 m. They were clustered together in an area of about one square foot (929 cm²), with at least five other individuals nearby. At times, these fish are in direct contact with conspecifics (Fig. 5). The cave is exposed to strong wave action and can be dived only on rare days when the sea is relatively calm. The fish are usually seen wedged in cracks to resist the force of the surge. They have thicker lower pectoral rays than specimens taken in calm localities, presumably from hypertrophy. While removing the smallest of the three specimens from his net, the second author received a slight prick of a dorsal spine on one thumb. It was surprisingly painful and caused the thumb to swell significantly. In spite of its small size, the venom of S. coniorta is to be respected. Sebastapistes coniorta exhibits surprising variation in color, as depicted in Figs 5-9. Two specimens with the most different color pattern were collected by the authors from a lava-tube cave at the shore of the Kona coast of the island of Hawai i; the largest specimen is illustrated here as Fig. 9. The cave, which extends inland beneath the shore, is totally dark in its rear part during the day. The fish have only a few dark spots and more red coloration, especially on the fins. We correlate the color differences with the lowlight level in the cave. Fig. 5. A pair of Sebastapistes coniorta from a cave off Lanai i Lookout, O ahu. Underwater photo by J. L. Earle. 65 aqua vol. 15 no April 2009

6 Variation in habitat and color of the Hawaiian scorpionfish Sebastapistes coniorta Fig. 6. Sebastapistes coniorta, BPBM 6464, 47 mm SL, Oah u. Photo by J. E. Randall. Fig. 7. Sebasapistes coniorta, BPBM 9987, 36 mm SL, O ahu. Photo by J. E. Randall. aqua vol. 15 no April

7 John E. Randall and John L. Earle Fig. 8. Sebastapistes coniorta, BPBM 34843, 75 mm SL, Midway. Photo by J. E. Randall. Fig. 9. Sebastapistes coniorta, BPBM 37270, 62 mm SL, from cave at shore, Kona, Hawai i. Photo by J. E. Randall. 67 aqua vol. 15 no April 2009

8 Variation in habitat and color of the Hawaiian scorpionfish Sebastapistes coniorta ACKNOWLEDGEMENTS We thank William N. Eschmeyer for taxonomic advice on scorpaenid fishes and Robert Whitton for assistance in the field and the preparation of Fig. 4. Helen A. Randall, Stuart Poss and Leo Smith reviewed the manuscript. REFERENCES BENNETT, E.T Observations on the fishes contained in the collection of the Zoological Society. On some fishes from the Sandwich Islands. Zoological Journal, London 4 (13, art. 3): ESCHMEYER, W. N. & RANDALL J. E The scorpaenid fishes of the Hawaiian Islands, including new species and new records (Pisces: Scorpaenidae). Proceedings of the California Academy of Sciences 40 (11): FOWLER, H.W The fishes of Oceania. Memoirs of the Bernice P. Bishop Msueum 10: iii pp. FOWLER, H. W. & STEINITZ Fishes from Cyprus, Iran, Iraq, Israel and Oman. Bulletin of the Research Council of Israel 5B (3-4): JENKINS, O. P Report on collections of fishes made in the Hawaiian Islands, with descriptions of new species. Bulletin of the United States Fish Commission 22 (for 1902): , GOSLINE, W. A The inshore fish fauna of Johnston Island, a Central Pacific atoll. Pacific Science 9 (4): GOSLINE, W. A. & BROCK V. E Handbook of Hawaiian Fishes. University of Hawai i Press, Honolulu. 372 pp. GÜNTHER, A Andrew Garrett s Fische der Südsee. Journal des Museum Godeffroy, parts 3, 6, 9, 11, 13, 15, 16, and 17 in vols. 2, 4, and 6. Hamburg. MYERS, R. F Micronesian Reef Fishes, ed. 3. Coral Graphics, Guam. vi pp. RANDALL, J. E Reef and Shore Fishes of the Hawaiian Islands. Sea Grant College Program of the University of Hawai i, Honolulu. xiv pp. RANDALL, J. E. & POSS, S. G Redescription of the Indo-Pacific scorpionfish Scorpaenopsis fowleri and reallocation to the genus Sebastapistes. Pacific Science 56 (1): SCHULTZ, L. P. & COLLABORATORS: WOODS, L. P. & LACH- NER, E. A Fishes of the Marshall and Marianas Islands. Vol. 3. Families Kraemeriidae through Antennariidae. Bulletin of the United States National Museum 202: vii pp. aqua vol. 15 no April