Meeting Abstract

P2.124  Saturday, Jan. 5  Pharyngeal jaw apparatus variation in cypriniform fishes RADE, CM*; HERNANDEZ, LP; George Washington Univ; George Washington Univ cristinarade@gmail.com

The pharyngeal jaw apparatus (PJA) is a novel feeding structure that distinguishes the morphologically diverse order of fishes, Cypriniformes. While perciform pharyngeal jaws of various fish groups, including cichlids, haemulids, and labrids have been examined, morphological diversity of cypriniform pharyngeal jaws has been mostly overlooked. Considering that the cypriniform PJA consists of significantly hypertrophied ceratobranchials 5 and loss of the upper pharyngeal jaws, a character seen only at the base of this group, it is crucial to investigate its anatomy and the variation therein. Here we describe the musculoskeletal differences characterizing the cypriniform PJA. We examine inter- and intra-familial morphological variation using both cleared and stained specimens and formalin-fixed specimens. Cypriniform clades examined exhibit either patterns of conserved morphology or significant variation at the familial level. Balitoridae and Gyrinocheilidae exhibit minimal intrafamilial variation but have distinct interfamilial differences. Alternatively while Cyprinidae and Cobitidae show common features at the subfamilial level, they show significant variation of the PJA at the familial level. While significant hypertrophy of the pharyngeal jaws characterizes most cypriniform fishes, gyrinocheilids tend to have smaller, more slender pharyngeal jaws and catostomids typically have an intermediate size; this is in strong contrast to the thicker and broader pharyngeal jaws of several of the examined cyprinids. Overall, this comparative study identifies various morphological features, including some that are potentially correlated with tropic niches and diets. Findings here will be help to elucidate the importance of the PJA in relation to cypriniform fishes’ trophic diversity and ecological success.