Larval development of the Cuatro Cienegas cichlid, Cichlasoma minckleyi

Ontogeny of Cichlasoma minckleyi was investigated with emphasis on developm ent of the trophic polymorphism involving the pharyngeal apparatus. At abou t 6 days post fertilization (5.3 mm SL; standard length) the fir st skull e lements that stained as ossified in cleared and stained specimens were isol ated, pointed pharyngeal teeth; also at this time jaw teeth were developing on the premaxilla and dentary. By 10 days after fertilization (6.2 mm SL) ca. 27 (estimated 11 top and 16.5 bottom) finger-like, pointed papilliform pharyngeal teeth were ossified in all specimens as the quadrate, angular, d entary, coracoid, parasphenoid, premaxilla, and maxilla were also ossifying . The skull roof and surrounding structures remained unossified.;UI specime ns lounger than 100 days (30 mm SL) had only papilliform pharyngeal teeth. Molariform pharyngeal teeth were observed only in older, larger (30 to 65 m m SL) specimens. Offspring of a molariform x molariform cross included mola riform, papilliform, and intermediate, pharyngeal morphologies.