Myogenesis of Siboglinum fiordicum sheds light on body regionalisation in beard worms (Siboglinidae, Annelida)

  title={Myogenesis of Siboglinum fiordicum sheds light on body regionalisation in beard worms (Siboglinidae, Annelida)},
  author={Nadezhda N. Rimskaya-Korsakova and Nadezda Karaseva and Timofei Pimenov and Hans Tore Rapp and Eve C. Southward and Elena N. Temereva and Katrine Worsaae},
  journal={Frontiers in Zoology},
Background Many annelids, including well-studied species such as Platynereis , show similar structured segments along their body axis (homonomous segmentation). However, numerous annelid species diverge from this pattern and exhibit specialised segments or body regions (heteronomous segmentation). Recent phylogenomic studies and paleontological findings suggest that a heteronomous body architecture may represent an ancestral condition in Annelida. To better understand the segmentation within… 

Sensory cells and the organization of the peripheral nervous system of the siboglinid Oligobrachia haakonmosbiensis Smirnov, 2000

The peripheral nervous system of O. haakonmosbiensis comprises epidermal solitary sensory cells, sensory spots around tubiparous glands openings, and putative sensory organs such as cephalic tentacles, an oval ciliary spot on the cep Halic lobe, the dorsal furrow, and papillae.



Myoanatomy of Myzostoma cirriferum (Annelida, Myzostomida): Implications for the evolution of the myzostomid body plan

A scenario on the rearrangements of muscle fibers that might have taken place in the lineage leading to this species is provided and suggests that the apparent partial radial symmetry of M. cirriferum arose secondarily in this species.

Cellular and muscular growth patterns during sipunculan development.

Data on cell proliferation and myogenesis during development of three sipunculan species, Phascolosoma agassizii, Thysanocardia nigra, and Themiste pyroides, supports a segmental ancestry of Sipuncula and shows a metameric pattern in the developing ventral nerve cord during the pelagosphera stage.

A metameric origin for the annelid pygidium?

The pygidium possesses a complicated nervous system with a nerve ring and a pair of sensory ganglia, a complex intrinsic musculature, a large terminal circular blood sinus and an unusual unpaired torus-shaped coelomic cavity, opening the debate on whether the pyGidium and trunk segments derive from the same ancestral metameric unit.

Neural architecture of Galathowenia oculata Zach, 1923 (Oweniidae, Annelida)

An immunocytochemical investigation of the nervous system of Galathowenia oculata is provided in order to discuss putative ancestral neuronal features in Oweniidae.

Integrative analysis of polychaete ontogeny: cell proliferation patterns and myogenesis in trochophore larvae of Sabellaria alveolata

It is found that in the first three segments the ventral transverse muscles differentiate from anterior to posterior, whereas the ventrals oblique muscles develop simultaneously, thus emphasizing the plasticity of the formation of metamerically arranged organ systems in polychaetes.

Detailed reconstruction of the nervous and muscular system of Lobatocerebridae with an evaluation of its annelid affinity

The neuromuscular and glandular system of Lobatocerebridae shows similarities to those of meiofaunal annelids such as Dinophilidae and Protodrilidae, yet likewise to Gnathostomulida and catenulid Platyhelminthes, all living in the restrictive interstitial environment among sand grains, which suggests an extreme evolutionary plasticity of annelid nervous and muscular architecture.

The normal development of Platynereis dumerilii (Nereididae, Annelida)

A staging ontology representing the comprehensive list of developmental stages of P. dumerilii normal development is provided and an overview of important steps in the development of the nervous system and of the musculature is provided using fluorescent labeling techniques and confocal laser-scanning microscopy.

Owenia fusiformis – a basally branching annelid suitable for studying ancestral features of annelid neural development

Owenia fusiformis turns out to be a valuable study subject for comparative investigations and unravelling ancestral processes in neural development in Annelida and Bilateria in general and strongly support that early branching annelids are comparable to other annalids with regard to larval neuroanatomy and formation of the juvenile nervous system.

The role of progenesis in the diversification of the interstitial annelid lineage Psammodrilidae

A combined phylogeny of Psammodrilidae is presented including molecular and morphological data of all eight described species as well as four undescribed species to reveal an unexpected diversity and distribution of this small family.

A Cambrian crown annelid reconciles phylogenomics and the fossil record

Dannychaeta tucolus is a new fossil polychaete (bristle worm) from the early Cambrian Canglangpu formation that belongs to crown annelids, and has characters that provide evidence of ecological and morphological diversity in ancient annelid evolution, thus reconciling the fossil record with molecular phylogenetic analyses.