Morphological differentiation within the Daphnia longispina group

• Published in: Hydrobiologia Vol. 442; no. 1-3; pp. 55 - 66
• Main Author: GIEBLER, Sabine
• Format: Conference Proceeding Journal Article
• Language: English
• Published: Dordrecht Springer 2001; Springer Nature B.V
• Subjects: Animals; Biological and medical sciences; Daphnia longispina; Discriminant analysis; Freshwater; Fundamental and applied biological sciences. Psychology; Genetics; Genetics of eukaryotes. Biological and molecular evolution; Hybrids; Invertebrata; Mountain lakes; Ponds; Population genetics, reproduction patterns; Speciation; Europe; Germany; Discriminant analysis; Daphnia longispina; Divergence; Cladocera; Genotype; Population genetics; Multidimensional scaling; Crustacea; Arthropoda; Morphology; Lakes; Phenotype variation; Bootstrap; Intraspecific comparison; Invertebrata; Branchiopoda
• ISSN: 0018-8158; 1573-5117
• DOI: 10.1023/A:1017504803506

Although morphological evolution is assumed to be slow within Daphnia species complexes, discontinuities in morphological space can be detected. Here, morphological data derived from females of genetically-defined clones (cf. Gießler et al., 1999) are presented, in order to estimate the genetic component of phenotypic variance under standardised laboratory conditions. Animals originated from clonal assemblages of pre-alpine lakes and ponds, and a remote lake in western Germany, covering a wide range of morphotypes known from the traditional species D. cucullata, D. galeata, D. hyalina, D. rosea, and a variety of interspecific hybrids. Phenotypic analyses were based on quantitative and qualitative morphological characters of females in the first and fifth instars. Morphological divergence between clones was analysed using discriminant analysis or multidimensional scaling and the significance of the morphological groupings was estimated using neighbour-joining trees and bootstrapping. All analyses confirmed that (a) phenotypic similarities among taxa change with instar, (b) in contrast to low genetic divergence, pronounced morphological divergence exists between animals separated on the lake/pond level favouring speciation by the habitat shift hypothesis.[PUBLICATION ABSTRACT]