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| Barbucca heokhuii Kottelat, 2025 Raffles Bulletin of Zoology. 73; |
Abstract
Barbucca heokhuii, new species, is described from the Kahayan drainage in central Borneo. It is
distinguished from the other species of the genus by its miniature size (the largest known specimen is 21.5 mm
SL), a truncate to rounded caudal fin, an incomplete lateral line, and a distinctive colour pattern made, among
others, of five pairs of irregular bars on the flank, narrower than interspaces, many of which may be dissociated
into several small blotches. It occurs in syntopy with B. diabolica. Sexual dimorphism is reported for the first time
for a member of the family; in males, the 2nd to 4th branched pectoral rays are thicker than the others and with
a patch of small tubercles along their posterior edge.
Key words. Cobitoidei, loach, miniature fish, sexual dimorphism, black water, peat swamp forest
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| Barbucca heokhuii, ZRC 66766, 16.2 mm SL; Borneo, Kalimantan Tengah: Kahayan drainage. (Photographs by Tan H. H.). |
Barbucca heokhuii, new species
Diagnosis. Barbucca heokhuiiis distinguished from the other
named species of Barbucca by having: a smaller adult size
(the largest known specimen is 21.5 mm SL, vs. 37.2 in B.
diabolica and 34.3 in B. elongata), a deeper body (depth
at dorsal-fin origin 17–21 % SL, vs. 14–18 in B. diabolica
and B. elongata); a truncate to rounded caudal fin (vs.
emarginated); the lateral line incomplete, reaching to below
posterior half of dorsal fin (vs. complete); absence of large
tubercles on head and body (vs. presence on posterior part of
flank, between above the tip of the pelvic fins and the base of
the caudal fin); anus about halfway between pelvic-fin base ...
Etymology. Named for Tan Heok Hui (LKCNHM) in
appreciation for his work on Southeast Asian fishes, and
especially fishes of peat swamp forests and loaches of
Borneo, and for the long lasting friendship, collaboration
and companionship in the field.
MAURICE KOTTELAT. 2025. Barbucca heokhuii, A New Species of loach from central Borneo (Teleostei: Barbuccidae). Raffles Bulletin of Zoology. 73; 54–66.
