Comparison of the predatory rotifers Pleurotrocha petromyzon (Ehrenberg, 1830) and Pleurotrocha sigmoidea Skorikov, 1896 (Rotifera: Monogononta: Notommatidae) based on light and electron microscopic observations

Abstract

In the course of phylogenetic investigations across Rotifera, we reinvestigated Proales sigmoidea (Skorikov, 1896) and found significant similarities with respect to its morphology, ecology and behaviour to Pleurotrocha petromyzon (Ehrenberg, 1830). Both species feed on stalked ciliates and show a similar habitus as well as similar virgate trophi. We here present new morphological details for both species based on light and electron micrographs. In light of our results, we suggest the reassignment of Proales sigmoidea to Pleurotrocha Ehrenberg, 1830. To further support our case, we provide additional comparisons with other species of the latter genus, including Pleurotrocha robusta (Glasscott, 1893), for which we present additional information.

Proales tillyensis sp.n. (Monogononta: Proalidae), a new rotifer species from North-West Germany, with reconstruction of its somatic musculature

“…With this study detailed data on the musculature of five species of Proalidae is available. Unfortunately, these data are not sufficient enough to make conclusions on the ground plan of Proales regarding the body musculature because it is assumable that Proales doesnt represent a monophyletic taxon (Wilts et al, 2009a). In fact, the distinct agreement of the somatic musculature of P. tillyensis sp.n.…”

“…The monogonont rotifer taxon Proalidae, Proales Gosse, 1886 comprises a genus with currently 44 species (Segers, 2007). From a systematic point of view Proales is problematic and in need of a revision because it represents an assemblage of diverse species from which several have been moved in and out in the past (Segers, 1995;Wilts et al, 2009a;De Smet, in press.). Koste (1978) already subdivided the species of Proales into two main groups: Group A (group Proales sensu stricto) comprises freshwater species that resemble the type species P. decipiens and are characterized by a tubular habitus with a trunk comprising multiple pseudosegments, a hardly offset head with a rostrum and a short foot, a cerebral eye and an elongated buccal field.…”

“…Koste (1978) already subdivided the species of Proales into two main groups: Group A (group Proales sensu stricto) comprises freshwater species that resemble the type species P. decipiens and are characterized by a tubular habitus with a trunk comprising multiple pseudosegments, a hardly offset head with a rostrum and a short foot, a cerebral eye and an elongated buccal field. The other group comprises almost unexceptionally marine species resembling Proales reinhardti (group B, misleadingly designated as group Proales sensu stricto by Wilts et al, 2009a). The representatives of this group are characterized by a bulbous trunk with an offset head and a long foot, apical eyes and two epidermal projections restricting the apical corona caudally.…”

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

“…A paired epidermal projection that restricts the corona caudolaterally (Fig. 3E) is present in different species of Pleurotrocha (Wilts et al. 2009a), in B. stylata (Wilts et al.…”

“…In a series of papers, we try to reveal new phylogenetic relevant morphological characters focusing on the inner and outer morphology of individual rotifer species from different taxa (see Riemann et al. 2009b; Wilts et al. 2009a,b; Wilts et al 2010) to contribute new data for future phylogenetic analyses.…”