This paper investigates alternation patterns in length, shape and orientation of dorsal cirri (fleshy segmental appendages) of phyllodocidans, a large group of polychaete worms (Annelida). We document the alternation patterns in several families of Phyllodocida (Syllidae, Hesionidae, Sigalionidae, Polynoidae, Aphroditidae and Acoetidae) and identify the simple mathematical rule bases that descr...

Progress in both molecular techniques and phylogenetic methods has challenged many of the interpretations of traditional taxonomy. One example is in the recognition of the animal superphylum Lophotrochozoa (annelids, mollusks, echiurans, platyhelminthes, brachiopods, and other phyla), although the relationships within this group and the inclusion of some phyla remain uncertain. While much of th...

The annelid genus Dayus was established by Steiner and Amaral (1999) for a single species Stratiodrilus cirolanae Führ, 1971 from South Africa. Nevertheless the genus name Dayus is preoccupied and was initially introduced by Mahmood (1967) for a typhlocybine leafhopper genus with Dayus elongatus Mahmood, 1967 as the type species from Singapore (Insecta: Hemiptera: Cicadellidae). Thus, the genus...

Developmental fates and cell lineage patterns are highly conserved in the teloblast lineages that give rise to the segmental ectoderm of clitellate annelids. But previous studies have shown that the pathways involved in specification of the ventrolateral O lineage and the dorsolateral P lineage differ to some degree in distantly related clitellate species such as the leeches Helobdella and Ther...

We investigated the development of dorsoventral and longitudinal musculature in all postembryonic stages of the kinorhynch Pycnophyes kielensis. Although the earliest stages have only 8 externally separated trunk segments, they already possess dorsoventral muscles for 10 (prospective) trunk segments. The last, 11th, pair is added in the third juvenile stage. Longitudinal musculature, in contras...

Sequencing of SSU rDNA showed that actinospores of the tetractinomyxon type, which develop in Chone infundibuliformis Krøyer (Annelida, Polychaeta, Sabellidae) from the northern Øresund, Denmark, are identical with Ceratomyxa auerbachi Kabata, 1962 (Myxozoa, Ceratomyxidae). This myxosporean was found in the gallbladder of the Atlantic herring Clupea harengus L. from the northern Øresund, Denmar...

Annelids (the segmented worms) have a long history in studies of animal developmental biology, particularly with regards to their cleavage patterns during early development and their neurobiology. With the relatively recent reorganisation of the phylogeny of the animal kingdom, and the distinction of the super-phyla Ecdysozoa and Lophotrochozoa, an extra stimulus for studying this phylum has ar...

The present study deals with the presence of Diopatramarocensis in the eastern Mediterranean. This species is small-sized and inhabited muddy bottom near the opening of rivers or lagoons [salinity range: 33-39‰] in the Aegean and Levantine Seas, and reached a maximum density of 90 ind.m(-2) in Mersin Bay. This species might be an alien species that was introduced from the East Atlantic (near Gi...

Although the phylogenetic position of brachiopods has always been subject to debate, many authors place them as a sister group to deuterostomes on the basis of morphological and developmental characters. However, molecular phylogeny consistently places them among protostomes. More precisely, brachiopods are predicted to branch inside the lophotrochozoan assemblage, together with annelids, mollu...

Thoracophelia (Annelida, Opheliidae) are burrowing deposit feeders generally found in the mid- to upper intertidal areas of sandy beaches. Thoracophelia mucronata (Treadwell, 1914) is found along the west coast of North America, including at Dillon Beach, CA. Two additional species, Thoracophelia dillonensis (Hartman, 1938) and T. williamsi (Hartman, 1938) were also described from this beach. T...