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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Glycera boeggemanni new species.
Long and robust sensitive palps are a synapomorphy of the scale worms Tab. Again, such a favorable selection pressure would have produced metamery several times independently within the Metazoa Clark Phylum Annelida Phylum Annelida little ring Segmented worms 15, species Marine worms freshwater worms terrestrial worms Leeches worldwide oolychaeta Soft The first tentacular cirri of Nereididae and the palps of Spionida are peristomial in position throughout development, but their inervation is clearly metameric Orrhage, Canadian Journal of Zoology 69 2: Ontogenetic, morphological and habitat modifications of larval types are found in many different low-level taxa.
Search Feedback Did you find what you were looking for? Others abbreviations used in the material examined: Leeches generally use suckers at their front and rear ends to move like inchworms. Xlasse der Zoologische Station Neapel The position of the Haplotaxidae in the evolution of the oligochaete annelids. However, it lacks some typical annelid features and has features which are not usually found in annelids and some of which are associated with other phyla.
They function as the main blood vessels, although they are side-by-side rather than upper and lower. The anus is on the upper surface of the pygidium.
Nereis alatopalpis Wesenberg-Lund, subjective synonym. Final report submitted to EPD. The parapodia of burrowing and tube-dwelling polychaetes are often just ridges whose tips bear hooked chetae. Despite much variation in the shape of the prostomium – e. These correlations classf corroborated by the congruence of all these individual characters in the present analyses. Since annelids are soft-bodiedtheir fossils are rare — mostly jaws and the mineralized tubes that some of the species secreted.
I22 and neuropodia Tab.
Since annelids are soft-bodiedtheir fossils are rare. Journal of zoological and Systematic evolutionary Research Actually, the entire transformation series involved in the shift from an errant to a burrowing mode, and then to a tubicolous habit is related to a gradual reduction of the posterior parapodia and a parallel development of the anterior appendages in the cephalic region. I5 may be partially or totally fused to the cephalic tagma in Phyllodocida and in the basal groups of eunicids and related taxa Nephtyidae Grube, and Amphinomidae Savigny, Fig.
In the figures of Pettibone The absence of gonoducts in segment 14 Tab. CapitellaNotomastusArenicolaMaldaneAxiothella.
Phylogenetic relationships of annelids, molluscs, and arthropods evidenced from molecules and morphology. Eaten by hydroids etc. Eucoelomate fluid filled body cavity.
Earthworms make a significant contribution to soil fertility. The issue of morphological homology.
The results of the present cladistic analyses reject both of these scenarios. Cladistic analysis of metazoan phyla and the placement of fossil problematica, p.
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As a result, some novel transformation series are suggested. However, shared features are Must all these coincidences be explained away as the result of developmental constraints see Sommer ?
The resolution of their phylogenetic position demands analyses at much lower levels of generality than has been possible to deal with herein. Annotated classification regeneration In metaplasia In regeneration: The formation of apodemes for muscle insertion and the development of new striated muscles for the articulation of exoskeletal plates imply in a complete reorganization of the muscular system Manton, First two parapodia uniramous, with single prechaetal and postchaetal lobe; following parapodia biramous, with two triangular to digitiform prechaetal lobes of about same length or notopodial lobe slightly shorter than the neuropodial one on anterior to median parapodia Figure 13dor notopodial lobe usually slightly shorter than neuropodial lobe on median to posterior parapodia Figure 13e ; two shorter, rounded postchaetal lobes, about same length; both lobes becoming slender on posterior parapodia.
Annelid – Classification |
Nucleic Acid Research 24 8: Placing Aphrodita as the sister group of Ecdysozoa makes the dorsal plates symplesiomorphic for those fossils. These annuli may represent a synapomorphy for these three taxa, although further confirmation in Paralacydoniidae is needed.
The branchiae of specimen ZUEC-BPO-ST did not present the fibrous muscular appearance of other specimens; rather, each branchia had a large number of gametes, with the lower branchia almost more inflated Figure 8 f.
All these states represent successive stages in the conquest of a sedentary way of life and then of continental environments. Synopsis and classification of living organisms. From intertidal to m depth; in this study, G. Class Hirudinea leeches Primarily freshwater, but also terrestrial and marine forms; small sucker at anterior end, large sucker at posterior end; fixed number of body segments at polychhaeta body cavity filled with connective tissue; hermaphroditic, with fertilized eggs laid in a cocoon secreted by clitellum; development direct without larval stages; about living species.
Aileron with triangular base Figure 2bsolid interramal plate indicating a larger specimen. Bristles and segmentation evident. Cahiers de Biologie marine Development of the gut and segmentation of newly settled stages of Ridgeia Vestimentifera: