Jaws and teeth of american cichlids (Pisces: Labroidei)

The morphology of the upper, lower, and pharyngeal jaws is very similar among American cichlids. Common conditions are: (1) the presence of a premaxillary dentigerous arm shorter than the ascending arm (exceptions are Astronotus, Cichla , and Crenicichla semifasciata ), (2) a narrow coulter area; in contrast, a broad coulter area is found in the Crenicichline Group, in certain chaetobranchines, and in Apistogramma , (3) the mandibular sensory canal exists to the skin through five or six simple pores; in contrast, it exits through numerous small pores that increase in number during ontogeny in the Chaetobranchine Group, certain crenicichlines, such as Cichla, Crenicichla lepidota, Crenicichla proteus , and Crenicichla vittata , and certain genera of the Cichlasomine Group A, such as Caquetaia, Petenia, Neetroplus , and “ Cichlasoma ,” and (4) the premaxilla and dentary of American cichlids commonly bear unicuspid, conical teeth with a few exceptions such as Neetroplus (with scraping blade teeth) and “ Cichlasoma” facetum, “C.” cyanoguttatum, “C.” guttulatum , and “ C.” spilurum (with bicuspid [hooked] teeth). In contrast to the near uniformity of the upper and lower jaws, the upper and lower pharyngeal jaws present a great diversity of tooth shapes. At least seven types are found in American cichlids; usually, several types exist on a single tooth plate, but the combination of tooth types differs among some genera. The pharyngobranchial 4 tooth plate has significant evolutionary transformations in labroids. The caudal margin of the pharyngobranchial 4 tooth plate bears the frayed zone in cichlids and embiotocids. The presence of a broad frayed zone bearing one to seven concavities represents a synapomorphy for the family Cichlidae, whereas a deep, narrow frayed zone is a synapomorphy of Embiotocidae. The absence of the frayed zone is a synapomorphy of Pomacentridae, whereas the loss of the pharyngobranchial 4 is a synapomorphy of Labridae. © 1993 Wiley‐Liss, Inc.