The musculature of three species of gastrotrichs surveyed with confocal laser scanning microscopy (CLSM)

Abstract

 AbstractLeasi, F., Rothe, B.H., Schmidt-Rhaesa, A. and Todaro, M.A. 2006. The musculature of three species of gastrotrichs surveyed with confocal laser scanning microscopy (CLSM). -Acta Zoologica (Stockholm) 87 : 171-180The muscular system of gastrotrichs consists of circular, longitudinal and helicoidal bands that when analysed with confocal laser scanning microscopy, provide new insights into their functional organization and phylogenetic importance. We therefore undertook a comparative study of the muscle organization in three species of Gastrotricha from the orders Macrodasyida ( Paradasys sp., Lepidodasyidae; Turbanella sp., Turbanellidae) and Chaetonotida ( Polymerurus nodicaudus , Chaetonotidae). The general muscle organization of the marine interstitial macrodasyidans, Paradasys and Turbanella , not only confirms earlier observation on other species but also adds new details concerning the organization and number of helicoidal, longitudinal and other muscle bands (e.g. semicircular band). The freshwater, epibenthic-epiphytic chaetonotid, Polymerurus nodicaudus , has a similar muscular organization to other species of Chaetonotidae, especially species of Chaetonotus , Halichaetonotus and Lepidodermella. Perhaps unique to Polymerurus is the combined presence of an unbranched Rückenhautmuskel (also in Halichaetonotus and Lepidodermella ) and a specialized dorsoventral caudal muscle, which flank the splanchnic component of the longitudinal muscles (only in Chaetonotus and Lepidodermella ). This combination, together with the presence of splanchnic dorsoventral muscles, known only in Xenotrichulidae, implies a unique phylogenetic position for Polymerurus , and indicates a potential basal position of this taxon among the Chaetonotidae studied so far (i.e. Aspidiophorus , Chaetonotus , Halichaetonotus and Lepidodermella ).

Muscular systems in gymnolaemate bryozoan larvae (Bryozoa: Gymnolaemata)

“…Musculature has been widely ignored in most studies on larval morphology so far, mainly because of methodic diYculties. However since methods like Xuorescence staining and confocal laser scanning microscopy (CLSM) are available, musculature meets these requirements, as already shown in many other metazoan groups (e.g., Wanninger 2004;Müller and Worsaae 2005;Wanninger et al 2005;Fuchs et al 2006;Leasi et al 2006;Schmidt-Rhaesa and Kulessa 2007). Three-dimensional analyses of muscular anatomy have already contributed to solve evolutionary or phylogenetic problems (Haszprunar and Wanninger 2000;Purschke and Müller 2006).…”

A phylogenetic approach to species delimitation in freshwater Gastrotricha from Sweden

“…Molecular studies of the interrelationships of Chaetonotida have so far suffered from poor taxon sampling and few included terminals (Wirz et al, 1999;Todaro et al, 2003Todaro et al, , 2006Zrzavý, 2003;Manylov et al, 2004) and are all based on the 18S rDNA gene.…”

“…A recent study of the phylogeny of Thaumastodermatidae showed that, within this family, not only molecular data and morphology are in general accordance, but also that there is homoplasy in the evolution of some cuticular structures. Indeed, additional data, such as the morphology of different organ systems (see e.g., Hochberg & Litvaitis, 2003;Leasi et al, 2006;Kieneke et al, 2008a;Leasi & Todaro, 2008) as well as gene sequence data should also be utilized for classification.…”

Myogenesis in Aplysia californica (Cooper, 1863) (Mollusca, Gastropoda, Opisthobranchia) with special focus on muscular remodeling during metamorphosis

“…On the one hand their phylogenetic value has been discussed and there were attempts to homologize distinct muscles in several phyla (Page, 1995(Page, , 1997(Page, , 1998Wanninger et al, 1999aWanninger et al, , 2000Haszprunar and Wanninger, 2000;Wanninger and Haszprunar, 2002a,b;Wolf and Harzsch, 2002;Mü ller and Sterrer, 2004;Filippova et al, 2005;Leasi et al, 2006;Raikova et al, 2006;Semmler et al, 2006). On the other hand functional implications may be concluded from the ontogeny of distinct muscles with respect to their overall gross anatomy, i.e., the impact of certain muscles during their development on the morphogenesis of the entire organism (e.g., Fretter, 1972).…”