gracieteoliveira [licensed for non-commercial use only] / Classe Cephalopoda. Cuvier, G. Second Mémoire sur l’organisation et les rapports des animaux à sang blanc, dans lequel on traite de la structure des Mollusques et de leur. Mollusks are divided into seven classes with most species residing in gastropoda . The class Cephalopoda is a remarkable group of mollusks.
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Pallial gland with oblique folds Fig. You may send this item to up to five recipients. Digital photos of all steps of the dissection were taken. Scaphopoda; Bivalvia; Diasoma; Filogenia; Morfologia.
No detected genital duct or pore. A scaphopod-like creature can be extracted from Pinnocarisby means of a greater and curved development mainly from the anterior region. Journal of Paleontology However, such a character looks rather like a plesiomorphy. Zur Evolution der Scaphopoden-Konstruktion. Pair of anterior pedal retractor muscles Figs.
In both scaphopods and bivalves, the visceral sac protrudes into the pallial cavity, forming a bulged sac at the ventral cladse of the foot. Gills posterior end supported by pair of suspensory stalks Clzsse. Gonad constituted for relatively long digital acini forming transverse folds; each acinus with almost half of gonad width and bifid distal end; gonadal folds highly protruding inside posterior half of pallial cavity, surrounding almost completely adjacent animal’s diameter.
This fold stays introduced between each hinge tooth and its respective socket at the opposed valve. Arquivos do Museu Nacional62 4: The taxon Protobranchia resulted paraphyletic. Glandular area located just posterior to folds absent, presenting another located closer to mantle edge Fig.
Tableau méthodique de la classe des Céphalopodes
The evolution of the ligament systems in the Bivalvia. Pair of ducts to digestive diverticula located ventral to esophageal insertion Figs. The “proboscis” form is based on structural similarities between the gadilid foot and the gastropod proboscis. Its appearance in node 7 is actually an artifact due to further modification of the modern examined solemyids. Despite the fact that the states of this character are not considered additive, the present result demonstrates that they can be regarded as such.
Journal of Paleontology13 1: The paleontology of rostroconch molluscs and the early history of the phylum Mollusca. Comparative morphology among representatives of main taxa of Scaphopoda and basal protobranch Bivalvia Mollusca. Both longitudinal muscles running towards anterior, restricted to ventral side, touching one another along median line.
Pallial component of main retractor muscle of foot: Notas e Estudos da Escola de Geologia1: This character, exclusive of the lamellibranchs, classee related to the increase of gills.
gracieteoliveira [licensed for non-commercial use only] / Classes do Filo Mullusca
In both Diasoma classes a clear tendency for ganglia to become distant from each other appears. Dorsal surface touching stomach centro-anterior region; ventral surface bulging inside pallial cavity; anterior and a portion of dorsal cphalopoda touching kidney. The homology of the mouth at the base of the oral tube, instead of its tip, is mainly based on the position of the nerve ring and odontophore.
Oxford University Press, Oxford, p. On some opisthobranchs from Florida. The evolution of the Scaphopoda and its implication for the systematics of the Rostroconchia Mollusca.
The mantle is still continuous dorsally, showing no clear clue of valve separation except cephalopora a fold that builds the hinge Fig. Beyond samples from Florida, some species from other regions and other taxa were selected in order to provide scenarios and outgroups for comparative analyses.
Digestive diverticula small, mixed with gonad. This study is developed under a phylogenetic methodology with the main concern in performing it in an intelligible and testable clasze. Foot capable of enfolding along itself at about half its length Figs. Reviews User-contributed reviews Add a review and share your thoughts with other readers.