Sipuncula

Phylogeny of sipunculan worms: A combined analysis of four gene regions and morphology

“…Character 41 (anus location): The anus is usually located dorsally at the anterior trunk. However, in two of the species included here, Phascolion gerardi and Onchnesoma steenstrupii it is shifted anteriorly onto the introvert (Rice, 1993;Shipley, 1892). Character coding-41.…”

“…The main sources for the following morphological characters were either direct observations or the following publications: Cutler (1994); Rice (1993) and Stephen and Edmonds (1972).…”

“…In sipunculans, nuchal organs are located close to the tentacles at the anterior introvert in sipunculans (Åkesson, 1958;Rice, 1993). The nuchal organs of only one species have been examined with ultrastructural methods (Purschke, 1997).…”

Re-evaluating the phylogeny of Sipuncula through transcriptomics

“…Thus far, it has been suggested that ancestral remnants of segmentation are reflected in neuronal architecture of the ventral nerve cord during larval development of sipunculans (Kristof et al, 2008(Kristof et al, , 2011Wanninger et al, 2009), which certainly warrants additional, more comprehensive studies. Third, sipunculans are valuable research organisms for reproductive biology (Rice, 1973(Rice, , 1989(Rice, , 1993Reunov and Rice, 1993;Adrianov and Maiorova, 2010), comparative development (Åkesson, 1958;Rice, 1967Rice, , 1975Rice, , 1988Schulze and Rice, 2009a) and life history character reconstruction and evolution (Jägersten, 1972;Rice, 1976Rice, , 1985. They are also emerging as important non-model organisms for evolutionary and developmental biology, or evo-devo (Schulze and Rice, 2009b;Wanninger et al, 2005Wanninger et al, , 2009Wanninger, 2008;Boyle and Seaver, 2010;Boyle and Rice, 2014).…”

Polychaete systematics: Past and present

“…Various cephalic sense organs are present in the nemerteans (called cephalic grooves, slits or pits, Turbeville 1991) and platyhelminths (Rieger et al 1991); ultrastructural comparisons have not yet been made between these and the polychaete nuchal organs. Sipuncula have a single median sensory organ associated with the cephalic pit (Rice 1993); this organ may have single or paired openings and may be variously lobulated and folded (Stephen & Edmonds 1972;Rice 1993;Cutler 1994). Nuchal organs are absent in Onychophora and Arthropoda (Schräm 1986).…”