?Developmental osteology of Ictalurus punctatus and Noturus gyrinus (Siluriformes: Ictaluridae) with a discussion of siluriform bone homologies

Abstract The skeleton of Siluriformes is characterized by several autapomorphies, including secondary absence, extreme modification, and purported fusion ossifications. Although well documented in adults, information on skeletal development catfishes relatively sparse typically focused particular regions the (e.g., Weberian apparatus). To further our understanding siluriform skeleton, I document entire two ictalurid species, Ictalurus punctatus (channel catfish) Noturus gyrinus (tadpole madtom) from five days pre-hatch to adult. reexamine homologies bones previously hypothesized represent compound elements as an additional element only known occur some ictalurids. Development complete I. at 22.4 mm SL almost N. (except dorsal- anal-fin distal radials) 14.1 SL. No signs ontogenetic were observed any elements. Previous hypotheses homology these ossifications are reviewed light developmental obtained herein. dermal parietal component present stage so-called parieto-supraoccipital. bone supraoccipital which ossifies lateral centers ossification later fuse, rather than a median center. ‘posttemporo-supracleithrum’ originates single center represents supracleithrum. posttemporal ictalurids many other canal-bearing between supracleithrum pterotic, sometimes identified extrascapular. extrascapular missing catfishes. Ictalurids have above posttemporal, either independently ossifying fragment or neoformation restricted members this family. chondral pectoral girdle that coracoid. scapula Dorsal-fin radial 2 absent foramen dorsal-fin spine formed modifications base fin-ray itself. Unlike loricarioid catfishes, urohyal solely sternohyoideus tendons. anteriormost infraorbital around sensory canal lacrimal. antorbital Finally, compared available for otophysans, cypriniforms Danio rerio Enteromius holotaenia characiform Salminus brasiliensis .