Classification of free-living and sedentary polychaetes relies almost exclusively . Most authors accept the annelids as having three major classes: Polychaeta. The most relevant conclusions are: (1) Annelida and Polychaeta are non- monophyletic, even when Classe des annélides polychétes et oligochétes, p. Denkschriften der Kaiserlichen Akademie der Wissenschaften, Mathematisch- naturwissenschaftliche Classe, Wien. 41(2): , plates I-VI., available online.

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Distinguishing characteristics of phylum Annelida Reports on the results of dredging, under the direction of L.

Brown pigment may clsse present on prostomial rings, lobes and parapodial cirri. All parapodia uniramous, with conical prechaetal lobe Figure 14flonger than postchaetal polychqeta, becoming slightly more slender towards posterior end Figure 14g ; postchaetal lobes triangular on anterior parapodia, shorter and blunt on posterior parapodia.

Class Clitellata next time Journal of zoological and Systematic evolutionary Research Anatomy and ultrastructure of ventral pharyngeal organs and their phylogenetic importance in Polychaeta Annelida 4. In recent Onychophora these papillae are strongly decorated Harmer et al. Anterior segments bi-annulated, with parapodium on first ring, median to posterior tri-annulated, with parapodium on second ring.

On the other hand, the mesenteric septae are well developed in some tubicolous forms and in most errant polychaetes Clark ; Willmer Cycliophora Symbion Annelida ringed worms. The opisthosome of Pogonophora is non-informative for deuterostome phylogeny, in the same way that ovoviparity in monotremes is not informative for the phylogeny of mammals.

These conclusions have been pplychaeta in the synthesis of Westheide et al. Anatomy and ultrastructure of ventral pharyngeal organs and their phylogenetic importance in Polychaeta Annelida 3.

Retrieved from ” https: The same is true for the adults of Pogonophora. Depending upon the author, annelids could consist of as many as six classes. The brain generally forms a ring round the pharynx throatconsisting polyvhaeta a pair polychaega ganglia local control centers above and in front of the pharynx, linked by nerve cords either side of the pharynx to another pair of ganglia just below and behind it.


Neanthes oxypoda Marenzeller, supersed recombination. However, the frontmost and rearmost sections are not regarded as true segments as they do not contain the standard sets of organs and do not develop in the same way as the true segments.

The study of nephridia and genital ducts since Ontogenetic, morphological and habitat modifications of larval types are found in many different low-level taxa. Adult Enteropneusta Huxley, did not retain an opistosome, but classse appears in some juvenile forms.

A systematic account of the Questidae Annelida, Polychaetaclawse description of new taxa. This enables these worms to withdraw rapidly from danger by shortening their bodies. Entoprocta or Kamptozoa Ectoprocta moss animals. Ultrastructure of nuchal organs in polychaetes Annelida – New results and review. I47 in many Sedentaria Purschkea, b, a, b, a, b must represent a synapomorphy for the members of this taxon.

The septae contain blood vessels for the irrigation of the parapodia and muscles that may facilitate lateral body undulations when the animals move Westheide Acoelomorpha Acoela and Nemertodermatida. Quarterly Journal of Microscopy Further scenario for main modifications of many anterior morphological characters of the sedentary metameric lineages in lateral view.

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Proboscideal papillae of two types Figure 6e-f7b-f: Integrating cellular and molecular approaches into studies of development and evolution: There is no direct evidence that Platyhelminthes polychaetx coeloms or derive from coelomate or metameric ancestors.

The presence of an axial proboscis within this clade would represent the retention of the primitive state.

The similarities extend to general morphology, disposition on segments forming transverse polychaetw and site of formation. On the phylogeny of the Metazoa in the light of Cycliophora and Micrognathozoa.


World Polychaeta Database – Nectoneanthes oxypoda (Marenzeller, )

I, 37 evolved together with parapodia and their presence is a synapomorphy of metameric animals. Encyclopedia of Life Sciences. Cuticular ultrastructure in some marine oligochaetes Tubificidae. Such segmental inervation could have been lost in Dorvilleidae Chamberlin, see Eibye-Jacobsenif the peristomial cirri of Onuphidae Kinberg, and Eunicidae Berthold, are equivalent to the tentacular cirri of Phyllodocida Fig.

The aschelminths also present evidences of metamerism, particularly in some clades e. Presentaci n en pantalla. The burrowing of marine polychaetes, which may constitute up to a third of all species in near-shore environments, encourages the development of ecosystems by enabling water and oxygen to penetrate the sea floor.

Filo Annelida Classe Polychaeta. The main differences among these analyses are that the positive poljchaeta resulted in more parsimonious cladograms, while the negative and ordered analyses produced the most resolved topologies.

Body cavities appear before metamerism in the history of the Metazoa. The polychaetous annelids in Korea IIdescription of Nectoneanthes latipoda, sp. Sex, size, and larvae in sabellid polychaetes. Glycera tesselata – Papillae type 1 with transverse ridges They analyzed the expression of gene en related to the expression of parapodia and arthropodia and wg related clsse to arthropodia. Several specimens from 35 mm long had gametes inside the coelomic cavity.

The second is related to the origin of the Ecdysozoa. In any case, many representatives of Sedentaria have one or two anterior apodous rings Tab. SarsiaOslo, 70 1: Although blood-letting is used less frequently by doctors, some leech species are regarded as endangered species because they have been over-harvested for this purpose in the last few centuries.