- Photo. (c) 2023 John Nevill
Scientific Name: Dascyllus abudafur
English Name: Indian Ocean humbug damselfish
Creole Name: Bweter
IUCN Red List Status: Not Evaluated (NE). [Assessed under the broader consideration of D. aruanus (Allen et al. 2022) where it was classified as Least Concern (LC). There is no reason to believe the classification for D. abudafur will be any different.]
Dorsal spines: 12; Dorsal rays: 11-13; Anal spines: 2; Anal rays: 11-13.
A small dascyllus. Margins of preorbital, suborbital, and preoperculum finely serrated. Caudal fin bilobate.
Colour: White base colour with three transversal black bands. The anterior band leaving a large white spot between the eyes. Lips dusky or white.
Pectoral fins transparent. Middle band incorporates black pelvic fins.Typically possesses a grey to blackish blotch at the base of the caudal fin that
distinguishes it from its Pacific-Ocean sister-species, Dascyllus aruanus, whose tail is generally entirely white.
Differs from D. aruanus by its cytochrome b gene sequence: nucleotide sites nos. 450, 459 and 702 of the gene (diagnostic between the two species) and
at these three sites, D. abudafur has the triplet (A, T, T) whereas D. aruanus has (G, C, C).
Maturity: Unknown. Max length : 10.0 cm TL. Common length : 6.0 cm TL.
Habitat and Ecology:
Occurs in the Indian Ocean: Red Sea to the Sunda Shelf. Inhabits shallow lagoon and subtidal reef flats (0-20 m depth).It has a close association with
branching corals. It is found in small to large aggregations. Feeds on zooplankton in the water column, benthic invertebrates, and algae. Diurnal.
Oviparous, distinct pairing during breeding.
This species is not protected or subject to fishery regulations. It is not subject to the artisanal fishery.
Photos taken at Port Launay (20/03/23) at 3-4 m depth.
Formerly considered as Dascyllus aruanus, genetic and phenotypic differences were identified (Borsa et al. 2014) that led to the western Indian Ocean
populations being distinguished as a distinct species. "Possesses a grey to blackish blotch at the basis of caudal fin that distinguishes it from its
Pacific-Ocean sister-species, Dascyllus aruanus, whose tail is generally entirely white. Also distinct from D. aruanus by its cytochrome b
gene sequence: nucleotide sites nos. 450, 459 and 702 of the gene are diagnostic between the two species (Fig.3). At these three sites, D. abudafur has
the triplet (A, T, T) whereas D. aruanus has (G, C, C)." (Borsa et al 2014).
Interestingly the specimen photo'd here exhibits a white tail which is more typical of the Pacific species - this is interpreted as variation within
D. abudafur, itself the consequence of incomplete morphological differentiation between the Indian Ocean and the Pacific Ocean species. The Borsa et al.
study which did find some white-tailed specimens but still found the genetic distinction.
Allen, G.R. et al. (2022). Dascyllus aruanus. The IUCN Red List 2022: https://dx.doi.org/10.2305/IUCN.UK.2022-2.RLTS.T188433A1874014.en. (21/03/23).
Borsa, P. et al. (2014). Resurrection of Indian Ocean humbug damselfish, Dascyllus abudafur (Forsskål) from synonymy with its Pacific Ocean sibling, Dascyllus
aruanus (L.). Comptes Rendus Biologies, 2014, 337, pp.709-716. 10.1016/j.crvi.2014.09.001.ird-01144018
Bray, D.J. (2020). Dascyllus aruanus in Fishes of Australia, https://fishesofaustralia.net.au/home/species/347 (21/03/23).
Froese, R. & D. Pauly. (Eds.) (2023). FishBase. Dascyllus abudafur (Forsskål, 1775). https://www.fishbase.se/summary/68973 (21/03/23).
Froese, R. & D. Pauly. (Eds.) (2023). FishBase. Dascyllus aruanus (Linnaeus, 1758). https://www.fishbase.se/summary/Dascyllus-aruanus.html (21/03/23).
Nevill, J.E.G. (2023). Dascyllus abudafur, Indian Ocean humbug damslefish. Seychelles Seatizens. www.seatizens.sc. https://seatizens.sc/species/dascyllus-abudafur-forsskal-1775/
There are no comments