Monday 28 September 2020

NOVATAXA: Rasbora marinae • A New Species of Cyprinid Fish

[Ichthyology • 2020] Rasbora marinae • A New Species of Cyprinid Fish (Cypriniformes: Danionidae) from northwestern Borneo

 Rasbora marinae 
Tan & Kottelat, 2020


 Rasbora marinae, new species, is described from Brunei Darussalam and northern Sarawak, Borneo. It shares with R. cephalotaenia the colour pattern of a mid-lateral stripe from tip of snout to end of median caudal-fin rays and rows of black spots on the flank, including two rows along edges of the mid-lateral stripe; it differs from R. cephalotaenia in retaining the mid-lateral stripe in adults, and in the absence of a conspicuous black blotch at the middle of the caudal-fin base. 

Key words. Southeast Asia, biodiversity, taxonomy, Cypriniformes, peat swamps

Fig. 1. Rasbora marinae, ca. 60 mm SL; Sarawak: Tatau; freshly caught specimen; not preserved.

Fig. 2. Rasbora marinae, Brunei.
A, ZRC 51189, holotype, 97.1 mm SL;
B, ZRC 51190, paratype, 36.5 mm SL.

Fig. 3. Rasbora cephalotaenia, colouration of freshly caught specimens.
A, Kahayan basin, clear water stream, ca. 50 mm SL;
B, Sebangau basin, black water stream, ca. 60 mm SL.

Fig. 6. Distribution of Rasbora cephalotaenia (squares) and Rasbora marinae (circles) in Borneo and Belitung Island. Hollow symbols represent type localities.

Rasbora marinae, new species

Diagnosis. Rasbora marinae is differentiated from congeners by the following combination of characters: a mid-lateral black or dark brown stripe from the tip of the snout to the end of the median caudal-fin rays; rows of black spots on the flank, including two rows along the edges of the midlateral stripe; lateral line complete, with 30–31 + 1–2 scales; 12 circumpeduncular scale rows. Rasbora marinae is very similar to R. cephalotaenia from which it differs in retaining the mid-lateral stripe in adults (vs. stripe disappearing with increasing size, leaving only the 2 rows of black spots along its edges), and the absence of a conspicuous black blotch at the middle of the caudal-fin base (vs. presence).

Distribution. Rasbora marinae is currently found in Belait and Tutong Districts, Brunei Darussalam; and in Sarawak, north of Tatau basin including Lambir Hills, to Baram basin (see map in Fig. 6; Zakaria-Ismail, 1984; Parenti & Meisner, 1995; Sulaiman & Shahdan, 2003; Tan & Lim, 2007; unpublished data).

Etymology. This species is named for Marina Wong (Brunei Museum, retired) in appreciation of her contributions to the knowledge of the natural history of Southeast Asia and her generous help in organising fieldwork in Brunei for the first author and team.

Tan Heok Hui and Maurice Kottelat. 2020. Rasbora marinae, A New Species of Cyprinid Fish from northwestern Borneo (Teleostei: Danionidae). RAFFLES BULLETIN OF ZOOLOGY. 68: 750–758. DOI: 10.26107/RBZ-2020-0086

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