Autapomorphies of Serrapinnus calliurus:

1. Transitional vertebrae with haemal canal (229): (1> 0) present. Reversal of synapomorphy 6 of node 195. Paralleled in Parecbasis cyclolepis .

2. Form and length of anterior anal-fin rays (290): (0> 1) longer and more compressed laterally than posterior rays.

3. Position of anal-fin bony hooks of adult males (316): (0> 1) medially positioned and oriented posteriorly.