title: Evolution of the premaxillary fraenum and substratum in snubnose darters and allies (Percidae: Etheostoma).
abstract: Darters (Percidae: Etheostomatinae), a species-rich group of North American freshwater fishes, vary in the presence of a premaxillary fraenum, a strip of skin that connects the premaxillary bones to the snout, and it is hypothesized that this trait is a trophic adaptation to particular substrata. Ancestral state reconstructions and analyses of phylogenetic associations between presence of the premaxillary fraenum and preferred stream substratum were conducted in a clade of closely related darters (snubnose darters and allies) that vary in morphology and habitat preferences. The most recent common ancestor of this clade was inferred to possess a fraenum and to inhabit rocky substrata, consistent with previous hypotheses, but a significant correlation between fraenum presence and substratum type across the phylogeny was not found.
authors.affiliation: Florida Museum of Natural History, University of Florida, 1659 Museum Road, Gainesville, FL, 32611, U.S.A.
authors.forename: P J
authors.initials: PJ
authors.lastname: Ciccotto
authors.affiliation: Department of Biological Sciences, University of Maryland, Baltimore County, 1000 Hilltop Circle, Baltimore, MD, 21250, U.S.A.
authors.forename: T C
authors.initials: TC
authors.lastname: Mendelson
mesh_terms: D000818:Animals; D005075:Biological Evolution; D016013:Likelihood Functions; D010471:Perches / Q000033:anatomy & histology* / Q000145:classification / Q000235:genetics; D010802:Phylogeny
keywords: Ulocentra; ancestral state reconstruction; benthic habitat; ecomorphology