Lookalikes
Stains of Danionella dracula specimens, showing the tooth-like processes that are present on the jaw of the male (left) and absent from the female (right). (Image: Ralf Britz, Natural History Museum)
Live individuals of D. dracula may be easily confused with the other 3 species of the genus due to their miniature size and lack of easily visible external characters. However, the diagnostic characters listed below - especially the pointed odontoid processes on the jaws of males, which resemble canine-like fangs - guarantee a problem-free identification upon closer inspection with a magnifying glass or microscope.
Diagnostic description
Danionella dracula is distinguished from its congeners, D. translucida and D.mirifica, and D. priapus by:
- the presence of a single bone in the upper jaw (versus 2)
- the presence of a single row of 6-13 odontoid processes in males on the dorsal surface of the dentary and on the ventral surface of the upper jaw, the anteriormost processes of which are large and canine-like (versus absence of processes)
- the lack of the maxillary-mandibular cartilage (versus its presence)
- the possession of:
- 7+8, 8+7 or 8+8 principal caudal fin rays (versus 9+9)
- 3-4 dorsal procurrent rays (versus 5-8)
- 2-3 ventral procurrent rays (versus 4-8)