Soleichthys siammakuti Wongratana, 1975

Matsunuma, Mizuki, Seah, Ying Giat, Kadir, Siti Tafzilmeriam Sheikh Abdul, Manjaji-Matsumoto, B. Mabel & Motomura, Hiroyuki, 2024, Reef-associated Bony Fishes of the Tropical Eastern Pacific: 2024 (VERSION 1) DATABASE, Cybium 48 (2), pp. 169-172 : 170-171

Soleichthys siammakuti Wongratana, 1975

( Fig. 3 )

The following specimens were examined: IPMB-I 01.00224 , 81.7 mm SL, off Kota Kinabalu, Sabah, Malaysia (obtained at Kota Kinabalu Central Fish Market ), B. M. Manjaji-Matsumoto & H. Nishiyama, 2 Aug. 2012; KAUM-I. 42116, 69.7 mm SL, Bindoy, Negros, Philippines, 9°45’N, 123°08’E, 15-20 Sep. 1981; KAUMI. 189729, 93.3 mm SL, KAUM-I. 189730, 84.1 mm SL, off Kuantan, Pahang, Malaysia (obtained at LKIM Fish Landing Port Kuantan), 3°45’N, 103°30’E, KAUM & UMT fish team, bottom trawl, 22 Sep. 2023. Counts and measurements (as % of SL) of the specimens were as follows: 73-80 dorsal-fin rays; 62-68 anal-fin rays; 8 and 7 pectoral-fin rays on ocular and blind sides, respectively; 5 pelvic-fin rays on both ocular and blind sides; 18 or 19 caudal-fin rays; 88-100 pored lateral-line scales; body depth 34.8-35.9; head length 16.8-18.9; suprapectoral width 16.8-18.7; subpectoral width 10.9-13.7; head width 20.3-25.5; head width at eye 16.8-21.0; caudal-fin length 14.8-16.0; caudal-peduncle width 7.4-8.5; pectoral-fin length 8.9-12.2; lower eye diameter 2.9-3.5; upper eye diameter 3.6-3.6; snout length 3.9-4.4; naris length 3.9-6.2; lower-jaw length 4.8-5.6; blind-side naris to snout 5.3-6.5; pectoral fin to lateral line 4.9-5.2; postorbital length 8.9-10.7 .

The present specimens ( Fig. 3 ) were identified as S. siammakuti , having the following combination of characters: 73-80 dorsal-fin rays; 62-68 anal-fin rays; 88-100 pored lateral-line scales; body with crossbands, darker bands much broader than lighter bands; dorsal, anal and caudal fins with large bright yellow spots when fresh (semitranslucent spots in preserved specimens); and 2 small white spots on lateral line (obscured in preserved specimens). Following the description of S. siammakuti by Wongratana (1975), two further species of Soleichthys have been recognized as valid, and four newly described. Soleichthys siammakuti can be readily distinguished from these and all other congeners by its unique color pattern, including crossbands on the body and yellow spots on the median fins (see Muchhala and Munroe, 2004; Munroe and Menke, 2004; Randall and Munroe, 2008).

Most of the count and measurement values of the present specimens differed from the original description of S. siammakuti [e. g., dorsal-fin rays 73-80 in the former vs. 80 in the latter; pored lateral-line scales 88-100 vs. 95 or 108, see Wongratana (1975: table 1)]. These differences are regarded as intraspecific variations, since the original description was based solely on two specimens. The smallest examined specimen (KAUM-I. 42116, 69.7 mm SL; Fig. 3D ) possessed elevated eyes with a broadly naked interorbital region, the latter being scaled in the other specimens (81.7-93.3 mm SL, interorbital region with 2-9 scale rows at level of mid-orbit). Wongratana (1975) had noted that the two type specimens (78.5- 82.4 mm SL) also possessed scales on the interorbital region. The smallest specimen also differed from larger specimens by having a broad light band basally on the caudal fin, and several light spots on the dorsal and anal fins roughly adjacent to light bands on the body. Underwater photographs of S. siammakuti registered in the Global Biodiversity Information Facility (GBIF) (see iNaturalist contributors & iNaturalist, 2023a, c), which appear to have been of small juveniles, indicated relatively large elevated eyes, with no scales on the narrow interorbital space. The GBIF-photographed individu- als also had a similar color pattern to KAUM-I. 42116, differing from adult specimens in having broader brown bands (iNaturalist contributors & iNaturalist, 2023c) or a brown body with whitish vermiculations (iNaturalist contributors & iNaturalist, 2023a). Allen and Erdmann (2012) reported underwater photographs of a “ Soleichthys species,” which had a similar colour pattern to S. siammakuti , but varied considerably according to locality and growth stage. To clarify the identification of those photographed individu- als, more information based on voucher specimens is required. At this stage, however, we tentatively identified the GBIF photographs as S. siammakuti , regarding the differences in interorbital squamation and coloration as growth-related intraspecific variations.

Soleichthys siammakuti was originally described by Wongratana (1975), based on two specimens from the northern Gulf of Thailand. Although the species has been recorded subsequently from Lembeh Strait, Indonesia, based on underwater photographs (iNaturalist contributors & iNaturalist, 2023a-c), the species is rare in museum collections worldwide, with no additional voucher specimens recorded. Although Hutchins (2001: 47) listed S. siammakuti in a checklist of the fishes of Western Australia, it is more likely that this record represents another species, subsequently described as new, e. g., Muchhala and Munroe (2004) and Munroe and Menke (2004). Therefore, the present specimens from Kuantan (east coast of Peninsular Malaysia), Kota Kinabalu (northeastern Borneo) and Negros represent the first specimen-based records of the species from Malaysia and the Philippines, indicating a widespread distribution in the South China Sea region ( Fig. 2 ).

Acknowledgments. – We are grateful to S. Kimura (FRLM), Y. Hibino (formerly FRLM), M. Nakae and K. Kobayashi (NSMT), J. Nakamura, T. Matsumoto, R. Cabebe, R. Koreeda, R. Furuhashi, and Y. Dewa (KAUM), T.N.A. Mat Jaafar, S.A. Mat Piah, N.A. Abd Latiff, R. Okamoto and M.S. Ali (UMT), and S.W. Abdurahman (IIUM) for their assistance during the survey at Kuantan, F.A. Asalin (IPMB) and G.S. Hardy (Ngunguru, New Zealand) for reading the manuscript and providing help with English. The first author is also grateful to the students of KAUM for their hospitality during his stay at their institution. This study was supported in part by Universiti Malaysia Terengganu (UMT) through a Strategic Research Grant (vote number 55435); JSPS KAKENHI Grant Numbers 20H03311, 21H03651, and 21K14905; the JSPS Core-to-Core CREPSUM JPJSCCB20200009; and the “Establishment of Glocal Research and Education Network in the Amami Islands” project of Kagoshima University adopted by the Ministry of Education, Culture, Sports, Science and Technology, Japan. Fish collection was done under MyABS permit number 600206, together with research approvals from Kelantan State Economic Planning Unit, Terengganu State Economic Planning Unit, Pahang State Biodiversity Council and Johor state Economic Planning Division. We wish to acknowledge the support and facilities provided by the Fisheries Development Authority of Malaysia (LKIM), Fishermen Association, Universiti Malaysia Terengganu, South China Sea Repository and Reference Centre and International Islamic University Malaysia Kuantan (IIUM). Special thanks go to the Japan Society for the Promotion of Science (JSPS): Core-to-Core project Collaborative Research and Education Project in Southeast Asia for Sustainable Use of Marine Ecosystems (CREPSUM) for continuing support of marine fish diversity studies. The authors thank two anonymous reviewers for their use- ful comments.

Figures

Figure 2. – Distributional records of Onigocia grandisquama (triangles) and Soleichthys siammakuti (circles) in the South China Sea and adjacent waters. Open and closed symbols indicate previous and present records, respectively. Circle with “P” indicates photographic records of S. siammakuti.

Figure 3. – Fresh (A-C) and preserved (D) specimens of Soleichthys siammakuti. A, B: KAUM-I. 189729, 93.3 mm SL, Kuantan, Pahang, Malaysia; C: IPMB-I 01.00224, 81.7 mm SL, Kota Kinabalu, Sabah, Malaysia (B: blind side); D: KAUM-I. 42116, 69.7 mm SL, Bindoy, Negros, Philippines.