Anellids Polychaete - Polychaeta

Polychaetes Polychaeta annelid phylum Policheti Anellidi intotheblue.it

Filograna implexa - Salmacina incrustans

Filograna implexa - Salmacina incrustans

La Filograna implexa vive in tutto il Mar Mediterraneo in piccolissimi tubicini intrecciati tra loro a profondità che possono variare dai 10 metri sino ad oltre 100 metri e laddove le condizioni glielo permettono ...
Protula dal ciuffo rosso - Protula tubularia

Protula dal ciuffo rosso - Protula tubularia

La Protula dal ciuffo rosso vive in tutto il Mar Mediterraneo in piccoli tubicini a profondità che possono variare dai 10 metri sino ad oltre 100 metri. Si tratta di un anellide molto comune in tutto il Mediterraneo ...
Serpulide - Hydroides Dianthus

Serpulide - Hydroides Dianthus

Il Serpulide Hydroides Dianthus è un Verme che appartiene al philum degli Anellidi, ed alla classe dei Policheti Sedentari e all’ordine dei Sabellidi ed al genere dei Serpulidi. ...
Spirografo - Sabella spallanzanii

Spirografo - Sabella spallanzanii

Lo Spirografo, Sabella spallanzanii è un anellide policheta marino della famiglia sabellidae. I nomi comuni includono il verme ventilatore Mediterraneo, il verme piumino,...
Spirografo Bispira viola - Sabella pavonina

Spirografo Bispira viola - Sabella pavonina

Lo Spirografo Bispira viola o verme pavone, Sabella pavonina , è un anellide policheta canalipalpato della famiglia dei Sabellidae. Lo troviamo nel Mar Mediterraneo ...
Vermocane - Hermodice carunculata

Vermocane - Hermodice carunculata

Il vermocane, Hermodice carunculata, detto anche verme cane, verme di fuoco o verme di mare, è un verme marino errante appartenente alla classe dei Policheti e alla famiglia Amphinomidae ...

Polychaetes (Polychaeta Grube, 1850) are the phylogenetically oldest class of the annelid phylum, comprising about 13,000 species. They are benthic animals and have a marine habitat.

Lo spirografo (Sabella spallanzanii) – intotheblue.it Polychaetes Polychaeta annelid phylum Policheti Anellidi intotheblue.it

Morphology

They present an indirect development for larvae of the trochophoric type, in which there is the presence of already differentiated and metamerized coelomatic pockets. The trocofora of polychaetes represents the classical form, is characterized by a typical spinning top and by two ciliate bands, prototypical and metatroco, which surround the surface roughly at the level of the equatorial plane. These bands work both for movement and for feeding through plankton filtration.

The development occurs with the elongation at the back and the beginning of the segmentation, so the most recent segments are those near the pigidium. Polychaetes Polychaeta annelid phylum Policheti Anellidi intotheblue.it

spirografo - serpulidae diantus - intotheblue.it

spirografo – serpulidae diantus – intotheblue.it Polychaetes Polychaeta annelid phylum Policheti Anellidi intotheblue.it

The size of most species ranges from 5 to 10 cm, but there are species that measure a few millimeters and others (Dasybranchus caducus) that can exceed the meter in length and the thickness of 2 cm.

The body shows a clear metameric segmentation. Polychaetes Polychaeta annelid phylum Policheti Anellidi intotheblue.it

There are three regions, prosthomia or cephalic region, metastomio or trunk and pigidium or tail. They are devoid of clitello (paracentral swelling rich in muciparous glands present in the earthworms instead).

The prostomium is the pre-oral segment, where the cerebral ganglia and sensory organs are located, including the eyes, the antennas or tentacles, the sensory palps and the nuchal organs; in the sedentary forms both the prostomium and the sensory organs can present themselves in very small dimensions. The peristomial or oral segment, where the mouth opens and where are the organs necessary for the capture of food and the sensory ones related to food. Prostomio and peristomio are not always well diversified, rather frequently they are more or less merged or overlapped. The buccal cavity is frequently evaginable and provided with chitinous papillae and mandibles. Polychaetes Polychaeta annelid phylum Policheti Anellidi intotheblue.it

The metastomio

The remaining metameric segments may be similar (metamer, homonym segmentation) or form clearly distinct regions (metamer, heteronomous segmentation); this is the case with some sedentary polychaetes. the most characteristic structures of the metastomie are the parapods. usually the parapods consist of two parts, a dorsal called notopodio, and a ventral one called neuropodio, both have a cirrus and are provided with bristles, the chitinous formations of a needle very characteristic from which the group name derives, which are connected by muscles to the ventral mesentery, this allows their movement and the consequent movement of the animal. Polychaetes Polychaeta annelid phylum Policheti Anellidi intotheblue.it

The pigidium

Some species have present and very visible parapods that allow them to crawl on the bottom (so-called wandering polychaetes). In many other species (so-called sedentary polychaetes), instead, the parapods are missing: they are often semisextile forms, sunk in the sediment through a tube produced by the secretions of epidermal cells (tubicolates). The composition of the tube is very varied, being able to be mucous, frequently mixed with particles of mud, sand or organic remains, membranous, chitinous or calcareous. Polychaetes Polychaeta annelid phylum Policheti Anellidi intotheblue.it

Some species, like the spirograph, are adorned with a rich and colorful crown of spiral tentacles.

 

Spirografo – Sabella spallanzanii – intotheblue.it Polychaetes Polychaeta annelid phylum Policheti Anellidi intotheblue.it

https://it.wikipedia.org/wiki/Polychaeta Polychaetes Polychaeta annelid phylum Policheti Anellidi intotheblue.it https://www.intotheblue.it/2016/09/12/muraena-helena-echinaster-sepositus-stylocidaris-affinis/ https://www.intotheblue.it/2019/01/22/il-serpulidae-hydroides-dianthus/ https://www.intotheblue.it/2017/09/29/lo-spirografo/ https://www.intotheblue.it/2019/06/08/hydroides-dianthus/ Polychaetes Polychaeta annelid phylum Policheti Anellidi intotheblue.it

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