title: Occurrence of four-spined Gasterosteus aculeatus in an isolated Croatian river population.
abstract: An isolated population of the three-spined stickleback Gasterosteus aculeatus in Croatia was found to have a high incidence of specimens either having a fourth dorsal spine or showing remnants of a fourth spine. Juvenile individuals showed a 9.4% incidence of a fourth spine. The population was examined for asymmetry of the skeletal defensive complex in order to determine whether the additional spine could be the result of developmental instability, a response to predation or environmental conditions.
authors.affiliation: Department of Zoology, Faculty of Science, University of Zagreb, Rooseveltov trg 6, 10000 Zagreb, Croatia. linda.zanella@zg.t-com.hr
authors.forename: L N
authors.initials: LN
authors.lastname: Zanella
authors.forename: D
authors.initials: D
authors.lastname: Zanella
authors.forename: M
authors.initials: M
authors.lastname: Mrakovcić
authors.forename: M
authors.initials: M
authors.lastname: Miletić
authors.forename: P
authors.initials: P
authors.lastname: Mustafić
authors.forename: M
authors.initials: M
authors.lastname: Caleta
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D017523:Croatia; D010641:Phenotype; D012044:Regression Analysis; D045483:Rivers; D023701:Smegmamorpha / Q000033:anatomy & histology* / Q000502:physiology*