Redescription of - a ubiquitous intertidal hoplonemertean found along the West Coast of North America.

Stimpson, 1857, a barnacle predator, is one of the most common and conspicuous intertidal nemerteans found along the West Coast of North America from Alaska to California, but it is currently referred to by the wrong name. Briefly described without designation of type material or illustrations, the species was synonymized with the Atlantic look-alike, (Johnston, 1837) by Coe. Here we present morphological and molecular evidence that is distinct from .

Pseudocnidae of ribbon worms (Nemertea): ultrastructure, maturation, and functional morphology.

The fine structure of mature pseudocnidae of 32 species of nemerteans, representatives of 20 genera, six families, and two classes was investigated with scanning and transmission electron microscopy. Pseudocnidae are composed of four layers (cortex, medulla, precore layer, and core) in most species investigated, but the degree of development and position of each layer can vary between different species. The secretion products comprising immature pseudocnidae segregate into separate layers: a thin envelope, which subsequently separates into the cortex and medulla and an extensive internal layer.

Pseudocnidae of archinemerteans (Nemertea, Palaeonemertea) and their implications for nemertean systematics.

The structure of pseudocnidae of 16 species of Palaeonemertea clade Archinemertea (= Cephalotrichida s.l.) was investigated with confocal laser, scanning, and transmission electron microscopy (TEM).

High Rates of Self-Fertilization in a Marine Ribbon Worm (Nemertea).

Organisms capable of self-fertilization ("selfing") typically exhibit two evolutionary syndromes: uniting high inbreeding depression with low levels of selfing, or low inbreeding depression with high levels of selfing. We examined the effect of inbreeding on fecundity and time to first reproduction in an apparently self-compatible, simultaneously hermaphroditic marine nemertean worm Prosorhochmus americanus. Adult and juvenile worms were raised in isolation or in pairs.

Morphology of the proboscis of Hubrechtella Juliae (Nemertea, Pilidiophora): implications for pilidiophoran monophyly.

The proboscis of Hubrechtella juliae was examined using transmission electron microscopy, scanning electron microscopy, and confocal laser scanning microscopy to reveal more features of basal pilidiophoran nemerteans for morphological and phylogenetic analysis. The proboscis glandular epithelium consists of sensory cells and four types of gland cells (granular, bacillary, mucoid, and pseudocnidae-containing cells) that are not associated with any glandular systems; rod-shaped pseudocnidae are 15-25 μm in length; the central cilium of the sensory cells is enclosed by two rings of microvilli. The nervous plexus lies in the basal part of glandular epithelium and includes 26-33 (11-12 in juvenile) irregularly anastomosing nerve trunks.

Disentangling ribbon worm relationships: multi-locus analysis supports traditional classification of the phylum Nemertea.

The phylogenetic relationships of selected members of the phylum Nemertea are explored by means of six markers amplified from the genomic DNA of freshly collected specimens (the nuclear 18S rRNA and 28S rRNA genes, histones H3 and H4, and the mitochondrial genes 16S rRNA and cytochrome c oxidase subunit I). These include all previous markers and regions used in earlier phylogenetic analyses of nemerteans, therefore acting as a scaffold to which one could pinpoint any previously published study. Our results, based on analyses of static and dynamic homology concepts under probabilistic and parsimony frameworks, agree in the non-monophyly of Palaeonemertea and in the monophyly of Heteronemerta and Hoplonemertea.