Early development of the endemic Delminichthys krbavensis (Leuciscidae, Cypriniformes) from a karstic field in Croatia
Marcic, Z., Jerkovic, A., Caleta, M., Buj, I., Zanella, D., Horvatic, S. and Mustafic, P.
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Abstract: This is the first report of the early development for the endemic Krbava minnow Delminichthys
krbavensis from a karstic field in Croatia, and the first report of any species of the genus Delminichthys.
The description is based on basic morphometric measures and meristic counts during a 48-day
observation of embryos and larvae acquired from successful spawning and rearing in an aquarium.
The mean total length of larvae at the time of hatching was 3.12 mm. Mouth opening and independent
feeding and intestinal function were observed after day 11 post-hatching (PH) at which time the
yolk sac was completely absorbed in all individuals. Flexion of the urostyle began after day 18 PH
and was completed by day 23 PH. Pectoral fins developed on day 7 PH, pelvic fins begin to develop
by day 44 PH and the formation of caudal, dorsal and anal fin was complete by day 48 PH, when
individuals presented the full set of soft rays. Understanding its early development is particularly
valuable in assessing the environmental impacts on this endangered species and is essential for its
effective monitoring and conservation.
Keywords: ontogeny; Krbava minnow; endangered species