Orthogastropoda
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Orthogastropoda | ||||||||||||
WF Ponder & DR Lindberg , 1996 |
The Orthogastropoda ( real snails ) form a taxon that was introduced by WF Ponder and DR Lindberg (1996); it is equivalent to the taxon Flexiglossata proposed by G. Haszprunar (1988) without definition.
Together with the taxon Eogastropoda ( early snails ), the Orthogastropoda form a monophyletic subdivision of snails and solve the problem of paraphyly of the prosobranchia of the systematics used until then. The taxon is part ( subclass ) of the systematics by Ponder & Lindberg (1997).
With the greater use of genetic engineering methods and more recent results, the cladistic, phylogenetic system was established by Bouchet & Rocroi (2005), which replaced the system by Ponder & Lindberg (1997). The Orthogastropoda are no longer included in this system .
The Orthogastropoda thus only form a temporary taxon , the use of which is restricted to the system of Ponder & Lindberg (1997).
Evolution of the taxon
G. Haszprunar (1988) and Ponder and Lindberg (1997) demonstrated that the previous large group of Prosobranchia within snails is paraphyletic . According to the rules of cladistics, a paraphyletic group must be resolved and divided into monophyletic groups. According to the cladistic analysis of Ponder and Lindberg (1997), the snails are therefore divided into two large groups: the Orthogastropoda and the Eogastropoda . They can be treated as subclasses in the linear-hierarchical sense. The Orthogastropoda contain part of the so-called prosobranchia as well as the opisthobranchia and the pulmonates . The subclass of the Eogastropoda also contains taxa that were assigned to the Prosobranchia, but also the groups that can be called "real limpets" ( Patellogastropoda ).
definition
The monophyly of the Orthogastropoda is based on a total of 15 synapomorphies . The most important are:
- a radula consisting of a flexible radula membrane ("flexiglossate radula"; hence the equivalent name Flexiglossata)
- the protoconch is separated from the juvenile housing
- In the adult stage there was originally an operculum (reduced in many groups)
- a simple, left hypobranchial gland ( secretion organ - in the purple snail the purple pigment is created from the secretion of this gland)
- Propodium with Fußdrüsen
- Vitreous eyes
- Pair of jaws not connected to the buccal apparatus
- a simple kidney on the right side of the pericardium
- an unpaired osphradium (organ of smell)
- ciliate zones on both sides of the osphradium
- an unpaired ctenidium ( gill )
Systematics
In the system of Ponder & Lindberg (1997) the Orthogastropoda are subdivided into 6 superordinate orders and a special taxon incertæ sedis for unassigned taxa. Within the 6 superorders which has superiority of "Hot Vent Taxa" also has a special status.
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Class Gastropoda G. Cuvier, 1797
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Subclass Orthogastropoda W.F. Ponder & DR Lindberg , 1996
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incertæ sedis
- Order † Murchisoniida Cox & Knight, 1964
- Superordinate "Hot Vent Taxa" WF Ponder & DR Lindberg , 1997
- Superorder Cocculiniformia G. Haszprunar, 1987
- Superorder Vetigastropoda L. Salvini-Plawen, 1987
- Superorder Neritaemorphi Koken, 1896
- Superorder Caenogastropoda Cox, 1960
- Superorder Heterobranchia JE Gray, 1840
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incertæ sedis
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Subclass Orthogastropoda W.F. Ponder & DR Lindberg , 1996
Other superordinate groups have been proposed among the fossil groups .
In the system of Bouchet & Rocroi (2005) the five established superordinates move up in the hierarchy and become clades . The "Hot Venta taxa" are included in the Vetigastropoda clade . The parentage Patellogastropoda from the subclass Eogastropoda becomes the sixth clade .
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Class Gastropoda G. Cuvier, 1797
- Grade basal taxa not sure to belong to Gastropoda
- Grade basal taxa that are confirmed to belong to Gastropoda
- Clade Patellogastropoda DR Lindberg, 1986
- Clade Vetigastropoda L. Salvini-Plawen, 1987
- Clade Cocculiniformia G. Haszprunar, 1987
- Clade Neritimorpha
- Clade Caenogastropoda Cox, 1960
- Clade Heterobranchia JE Gray, 1840
Individual evidence
- ↑ J. Thiele (1929-1935). Manual of systematic molluscology. 2 volumes. 1-1154.
- ^ R. Bieler & PM Mikkelsen (Sci.Ed.); JS Bhatti (Transl.); J. Thiele Handbook of Systematic Molluscology. English: Handbook of systematic malacology. Publ: Washington, DC; Smithsonian Institution Libraries; National Science Foundation; 1992-. Content: pt. 1. Loricata; Gastropoda: Prosobranchia - pt. 2. Gastropoda: Opisthobranchia and Pulmonata - pt. 3. Scaphopoda / Bivalvia / Cehalopoda - pt. 4. Comparative Morphology / Phylogeny / Geographical Distribution. Catalog-No: OCLC 16004796 .
- ^ A b W. F. Ponder & DR Lindberg (1997). Towards a phylogeny of gastropod molluscs: an analysis using morphological characters. In: Zoological Journal of the Linnean Society. 119 (2): 83-265. doi : 10.1111 / j.1096-3642.1997.tb00137.x .
- ↑ a b P. Bouchet, & J.-P. Rocroi: Part 2. Working classification of the Gastropoda. In: Malacologia. 47: 239-283; Ann Arbor 2005; ISSN 0076-2997
- ↑ a b P. Bouchet & J.-P. Rocroi (Ed.): J. Frýda, B. Hausdorf, WF Ponder, Á. Valdés & A. Warén (2005). Classification and nomenclator of gastropod families. In: Malacologia: International Journal of Malacology. 47 (1-2). ConchBooks: Hackenheim, Germany. ISBN 3-925919-72-4 . ISSN 0076-2997 . 397 pages. http://www.vliz.be/Vmdcdata/imis2/ref.php?refid=78278
- ↑ a b GT Poppe, & SP Tagaro: February 23, 2006; The New Classification of Gastropods according to Bouchet & Rocroi, 2005. online ( Memento of the original of September 27, 2007 in the Internet Archive ) Info: The archive link was automatically inserted and not yet checked. Please check the original and archive link according to the instructions and then remove this notice. (PDF; 191 kB).
- ↑ G. Haszprunar: On the origin and evolution of major gastropods group, with special reference to the streptoneura. In: J. Moll. Stud. 54: 367-441; 1988, doi : 10.1093 / mollus / 54.4.367 .
literature
- GM Barker: Gastropods on Land: Phylogeny, Diversity and Adaptive Morphology. In: The Biology of Terrestrial Molluscs. Cabi Publishing, 2001, ISBN 0-8519-9318-4 , doi : 10.1079 / 9780851993188.0000 .