The skull in normal and pugheaded females of the mosquitofish Heterandria formosa Agassiz, 1853 (teleostei, poeciliidae)
Riehl, R.; Schmitt, P.
Gegenbaurs Morphologisches Jahrbuch 131(2): 261-270
1985
ISSN/ISBN: 0016-5840 PMID: 4007457 Document Number: 254134
Normal and pugheaded skulls in Heterandria formosa were studied by a modified Spalteholz-method, scanning electron microscopy, and X-ray projection microscopy. Pugheadedness was examined for the first time in this fish species. X-ray projection microscopy quickly produces useful results of fish morphology. The modified Spalteholz-method, however, has a higher resolution and single bones and bone sutures can be demonstrated. In pugheaded skulls of Heterandria formosa the neurocranium and upper jaw are shortened, whereas the lower jaw usually remains unaltered. The pugheadedness in H. formosa involves not only a shortening of the vomer, parasphenoid, and maxillaries, but also by displacement and/or curve of the nasals, frontals, vomer, and palatines. For these reasons, the forehead is upraised and steep in pugheads. The origin of pugheadedness is discussed.