Delimitation of Cecidophyopsis and Cecidophyes (Eriophyidae: Cecidophyinae) species – linear morphometric methods

Abstract

Although eriophyoids are considered a group of microscopic organisms with simplified bodies, more than 100 characters and 250 character states related to the body and legs can be used in their systematics. It has been demonstrated that some of these taxonomic characters are more prone to homoplasy. The aim of this study was to evaluate the diagnostic value of 35 morphological traits, analyzed by linear morphometrics, for the delimitation of 14 species from two genera: Cecidophyopsis (C. vermiformis, C. ribis, C. malpighianus, C. hendersoni, C. verilicis, C. rosmarinusis and C. psilaspis) and Cecidophyes (Ce. galii, Ce. rouhollahi, Ce. glaber, Ce. gymnaspis, Ce. nudus, Ce. psilonotus and Ce. lauri). Multivariate analysis of variance (MANOVA) revealed statistically significant interspecies differences (Wilks’λ = 0.0000; F455,4357.726 = 65; P = 0.0000). Canonical variate analysis (CVA) indicated clear segregation of species belonging to Cecidophyopsis and Cecidophyes genera along the CV1 axis. This trend was also supported by the UPGMA cluster analysis. Morphological traits that contributed most to the distinguishing along the CV1 axis were: numbers of dorsal and ventral semiannuli, body width at the level of the f and c2 setae, distances between the 1b - 1a tubercles, distance between d setae and prodorsal shield width. According to the squared Mahalanobis distances, the greatest morphological separation was between C. hendersoni and C. ribis (Cecidophyopsis cluster) and Ce. psilonotus and Ce. lauri (Cecidophyes cluster). In addition, C. vermiformis and C. ribis (Cecidophyopsis cluster), as well as Ce. galii and Ce. glaber (Cecidophyes cluster), showed morphologically very close relationships.