Abstract
Betta nuluhon, new species, is described from a hill stream habitat in western Sabah. This species is allied to both B. chini and B. balunga, and differs from rest of its congeners in the B. akarensis group in having the following combination of characters: yellow iris when live; mature males with greenish-blue iridescence on opercle when live; mature fish with distinct transverse bars on caudal fin; slender body (body depth 22.1–25.2 % SL); belly area with faint reticulate pattern (scales posteriorly rimmed with black); absence of tiny black spots on anal fin; lateral scales 29–31 (mode 30); predorsal scales 20–21 (mode 20). Notes on a fresh series of B. chini are also provided.
References
de Beaufort, L.F. (1933) On some new or rare species of Ostariophysi from the Malay Peninsula and a new Betta from Borneo. Bulletin of the Raffles Museum, 8, 31–36.
Britz, R. (2001) The genus Betta—monophyly and intrarelationships, with remarks on the subfamilies Macropodinae and Luciocephalinae (Teleostei: Osphronemidae). Ichthyological Explorations of Freshwaters, 12, 305–318.
Herre, A.W.C.T. (1940) Additions to the fish fauna of Malaya and notes on rare or little known Malayan and Bornean fishes. Bulletin of the Raffles Museum, 16, 27–61.
Inger, R.F. & Chin, P.K. (1962) The fresh-water fishes of north Borneo. Fieldiana, Zoology, 45, 1–268.
Low, B.W. (2019) Betta chini. The IUCN Red List of Threatened Species, 2019, e.T2781A91307844.
https://doi.org/10.2305/IUCN.UK.2019-2.RLTS.T2781A91307844.en
Ng, C.K.C., Abdullah, F., Biun, H., Ibrahim, M.K., Mustapha, S. & Sade, A. (2017) A working checklist of the freshwater fish diversity for habitat management and conservation work in Sabah, Malaysia, North Borneo. Biodiversitas, 18, 560–574.
https://doi.org/10.13057/biodiv/d180217
Ng, P.K.L. (1993) On a new species of Betta (Teleostei: Belontiidae) from peat swamps in Sabah, East Malaysia, Borneo. Ichthyological Exploration of Freshwaters, 4 (4), 289–294.
Phua, M.-H., Tsyuti, S., Lee, J.S. & Sasakaw, H. (2007) Detection of burned peat swamp forest in a hetrogenous tropical landscape: A case study of the Klias Peninsula, Sabah, Malaysia. Landscape & Urban Planning, 82 (3), 103–116.
https://doi.org/10.1016/j.landurbplan.2007.01.021
Rüber, L., Britz, R., Tan, H.H., Ng, P.K.L. & Zardoya, R. (2004) Evolution of mouthbrooding and life-history correlates in the fighting fish genus Betta. Evolution, 58 (4), 799–813.
https://doi.org/10.1111/j.0014-3820.2004.tb00413.x
Schindler, I. & Schmidt, J. (2008) Betta kuehnei, a new species of fighting fish (Teleostei: Osphronemidae) from the Malay Peninsula. Bulletin of Fish Biology, 10 (1/2), 39–46.
Tan, H.H. (2009) Redescription of Betta anabatoides Bleeker, and a new species of Betta from West Kalimantan, Borneo (Teleostei: Osphronemidae). Zootaxa, 2165 (1), 59–68.
https://doi.org/10.11646/zootaxa.2165.1.5
Tan, H.H. & Ahmad, A. (2018) Betta omega, a new species of black water fighting fish (Teleostei: Osphronemidae) from Malaysia. Raffles Bulletin of Zoology, 66, 402–407.
Tan, H.H. & Lim, K.K.P. (2004) Inland fishes from the Anambas and Natuna Islands, South China Sea, with description of a new species of Betta (Teleostei: Osphronemidae). Raffles Bulletin of Zoology, Supplement 11, 107–115.
Tan, H.H. & Ng, P.K.L. (2004) Two new species of freshwater fish (Teleostei: Balitoridae, Osphronemidae) from southern Sarawak. In: Yong, H.S., Ng, F.S.P. & Yen, E.E.L. (Eds.), Sarawak Bau Limestone Biodiversity Sarawak Museum Journal, New Series, Special Issue No. 6, LIX (No. 80), pp. 267–284.
Tan, H.H. & Ng, P.K.L. (2005) The fighting fishes (Teleostei: Osphronemidae: genus Betta) of Singapore, Malaysia and Brunei. Raffles Bulletin of Zoology, Supplement 13, 43–99.
Tan, H.H. & Ng, P.K.L. (2006) Six new species of Betta (Teleostei: Osphronemidae) from Borneo. Ichthyological Exploration of Freshwaters, 17 (2), 97–114.
Tan, H.H. & Kottelat, M. (1998) Two new species of Betta (Teleostei: Osphronemidae) from the Kapuas basin, Kalimantan Barat, Borneo. Raffles Bulletin of Zoology, 46 (1), 41–51.
Witte, K.E. & Schmidt, J. (1992) Betta brownorum, a new species of anabantoids (Teleostei: Belontiidae) from northwestern Borneo, with a key to the genus. Ichthyological Exploration of Freshwaters, 2 (4), 305–330.