Phylogeny of Dicranophoridae (Rotifera: Monogononta) - a maximum parsimony analysis based on morphological characters

Abstract

This study presents the first phylogenetic analysis of Dicranophoridae (Rotifera: Monogononta), a species rich rotifer family of about 230 species currently recognized. It is based on a maximum parsimony analysis including 77 selected ingroup and three outgroup taxa and a total of 59 phylogenetically informative morphological characters. Character coding is based on personal investigation of material collected by the authors and an extensive survey of the literature. Apart from covering general body organization, character coding primarily relies on scanning electron microscopic preparations of the mastax jaw elements. Our study suggests monophyly of Dicranophoridae with a clade of Dicranophorus and Dorria as the sister taxon of all other dicranophorid species. Monophyly of Encentrum, the most species rich genus within Dicranophoridae, cannot be demonstrated. Within Dicranophoridae our study identifies the monophyletic taxa Caudosubbasifenestrata, Intramalleata, Praeuncinata and Proventriculata, each based on unambiguous character transformations evolved in their stem lineages. However, resolution within Praeuncinata and Proventriculata is very limited. Although some terminal clades within Praeuncinata and Proventriculata are recognized, basal splits remain obscure. Probably, other characters such as DNA sequence data are needed to further our understanding of phylogenetic relationships within these poorly resolved taxa.

The musculature of Squatinella rostrum (Milne, 1886) (Rotifera: Lepadellidae) as revealed by confocal laser scanning microscopy with additional new data on its trophi and overall morphology

“…Squatinella rostrum displays a paired ventral and a paired dorsal longitudinal muscle (musculus longitudinalis ventralis and musculus longitudinalis dorsalis) that can reasonably be assumed as homologous with the dorsal and ventral longitudinal muscle pairs in Be. eudactylota and B. stylata because these muscles have been considered to be ground pattern features of Ploima (see Riemann et al. 2009a and Wilts et al.…”

“…Therefore, morphological studies on the trophi of Lepadella are necessary to verify our assumption that a dorso‐caudal orientation of the ramus foramen sub‐basalis represents a synapomorphy for all genera of the Lepadellidae. This character can be observed in some species of Encentrum as well but both traits seem to have evolved independently because the character is derived within Dicranophoridae (see also Riemann et al. 2009a) and no evidence for a closer relationship of these genera exists.…”

Body musculature of Beauchampiella eudactylota (Gosse, 1886) (Rotifera: Euchlanidae) with additional new data on its trophi and overall morphology

“…The total body length from the frontal edge of the rotatory organ (cilia not considered) to the caudal tip of the toes is treated as 100 units. For our description of the relative positions of the individual mastax jaw elements (trophi), we use terms introduced previously (see Riemann and Ahlrichs 2008; Riemann et al . in press).…”

The evolution of the protonephridial terminal organ across Rotifera with particular emphasis on Dicranophorus forcipatus, Encentrum mucronatum and Erignatha clastopis (Rotifera: Dicranophoridae)

“…In the present study, we focus on the terminal organs in Dicranophorus forcipatus (Müller 1786), Encentrum mucronatum Wulfert 1936 and Erignatha clastopis (Gosse 1886) as members of the species rich taxon Dicranophoridae, for which no data have been published. We provide reconstructions of their ultrastructure based on complete ultrathin serial sections and evaluate our findings against the background of a recent phylogenetic analysis of Dicranophoridae (Riemann et al . 2009).…”