Morphological variation in Gyrinus sericeolimbatus Rég. in New Guinea and description of a new Gyrinus species (Coleoptera: Gyrinidae)

Abstract

Abstract. Samples of Gyrinus sericeolimbatus from twenty‐six localities in New Guinea vary greatly in metric body characters as well as in elytral reticulation patterns. The variation is smaller within than between populations. Although the characters of adjacent populations are usually similar, certain proximate populations exhibit significant differences, probably resulting from some kind of dispersal barrier. Similarities between populations at comparable latitudes suggest that some of the morphological variation is altitude‐related. In addition, evidence is found for habitat‐related morphological differentiation. Changes in phenotypes in response to possible environmental factors in ontogeny and constraints imposed by various selection pressures are discussed. A new species, G.brincki sp.n., from western New Guinea is described.