Middle Cambrian monoplacophorans from Bornholm and Australia, and the systematic position of the bellerophontiform molluscs

Berg‐Madsen, Vivianne; Peel, John S.

doi:10.1111/j.1502-3931.1978.tb01295.x

Cited by 43 publications

(40 citation statements)

References 9 publications

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“…Pojeta & Runnegar, 1976;Salvini-Plawen, 1980, 198 1, 1984Dzik, 1981), or they are torted gastropods (e.g. Yonge, 1947;Knight, 1947Knight, , 1952Cox, 1960a;Cox & Knight, 1960;Berg-Madsen & Peel, 1978;Stasek, 1972;Gollkov & Starobogatov, 1975;Yochelson, 1978;Harper & Rollins, 1982;McLean, 1984;Haszprunar, 1988a;Peel, 199 1). This divergence in opinion is in part due to bellerophontoideans being a polyphyletic assemblage composed of both monoplacophorans and gastropods.…”

Section: Vetigastropodamentioning

confidence: 97%

Towards a phylogeny of gastropod molluscs: an analysis using morphological characters

Ponder

Lindberg

1997

Zoological Journal of the Linnean Society

535

301

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Morphological (including ultrastructural) and developmental characters utilized in recent literature are critically reviewed as the basis to reassess the phylogenetic relationships of gastropods. The purpose of this paper is to provide a framework of characters for future studies and a testable phylogenetic hypothesis. This is one of the fvst attempts to use such characters to assess the relationships of all major clades using parsimony methods. The analysis uses 1 17 characters and includes 40 taxa, predominantly 'prosobranchs'. Five outgroup taxa are included, representing four conchiferan groups and Polyplacophora. Of the 1 17 characters reviewed and included in the analyses, nine are shell characters (four of these are shell structure), two opercular, two muscular, four ctenidial, 12 renopericardial and 24 reproductive (including 17 based on sperm and spermatogenesis), 27 of the digestive system, 32 of the nervous system and sense organs; the remainder are developmental (3) and of the foot and hypobranchial gland. In the initial analysis the data set included a mixture of binary and multistate characters with all characters unordered. These data were also analysed after scaling so that each character had equal weight. A third data set was constructed in which all characters were coded as binary characters. These analyses resulted in some implausible character transformations, mainly involving the regaining of lost pallial structures. Additional analyses were run on all three sets of data after removing five characters showing the most unlikely transformations. These analyses resulted in generally similar topologies. The robustness of the clades was tested using clade decay. The adaptive radiation of gastropods and their life history traits are briefly described and discussed and the terminology for simultaneous heririaphroditism refined. A scenario for the evolution of torsion equated with the fossil record is proposed and the effects of torsion and coiling on gastropods are discussed along with asymmetry imposed by limpet-shaped body forms. It is suggested that the first gastropods were ultradextral. The idea that heterochrony has played a major part in gastropod evolution is developed and discussed, particularly the paedomorphic stamp imposed on thc apogastropods. The veliger larvae of caenogastropods and heterobranchs are contrasted and found to differ in many respects. The evolution of planktotrophy within gastropods is discussed. Recent phylogenetic hypotheses for gastropods based on molecular data are generally in broad agreement with the present results. On the basis of our analyses we discuss the major monophyletic groups within gastropods. Gastropods appear to be a nionophyletic clade, and divide into two primary groups, the Eogastropoda (incorporating the patellogastropods and their (probably sinistrally coiled) ancestors and the Orthogastropoda ~ the Correspondence to W.F. Ponder. GASTROPOD PHYLOGENE'remainder of the gastropods. Orthogastropoda comprises several well defined clades. The vetigastrop...

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Section: Vetigastropodamentioning

confidence: 97%

Towards a phylogeny of gastropod molluscs: an analysis using morphological characters

Ponder

Lindberg

1997

Zoological Journal of the Linnean Society

535

301

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“…Discussion. -We are unable to satisfactorily locate Beyrichidiscus within any suprageneric taxon of the Monoplacophora due to the current lack of an acceptable classification (see discussion in Berg-Madsen & Peel 1978;Peel 1980 Knight et al (1960), is more laterally compressed with narrowly phaneromphalous umbilici and crenulate apertural lips.…”

mentioning

confidence: 95%

“…In the isostrophically coiled shells of the Palaeozoic bellerophontiform molluscsa complex of torted gastropods and untorted monoplacophorans whose systematic subdivision is currently the subject of some debate (Runnegar & Jell 1976;Berg-Madsen & Peel 1978;Linsley 1978a;Peel 1980) -allometric growth is commonly reflected in progressive changes in the rate of whorl expansion and in the width of the umbilici from the juvenile to the adult (Peel 1974). Many genera, such as Tremanotus Hall 1865, Anapetopsis Peel 1975, Salpingostoma Roemer 1876, also develop a widely expanded, explanate, sometimes bell-shaped final growth stage (Peel 1972(Peel , 1975(Peel , 1977.…”

mentioning

confidence: 99%

“…The allometric morphological changes of the adult Beyrichidiscus are, in total, without parallel in the bellerophontiform molluscs. Some tremanotins and forms resembling Salpingostoma show superficially similar lateral swellings (Berg-Madsen & Peel 1978;Koken & Perner 1915), but their location and repeated occurrence make any comparison with the swellings in Beyrichidiscus tenuous. The monoplacophoran Sinuites Koken 1896 displays comparable lateral shields in the adult, but is otherwise dissimilar.…”

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confidence: 99%

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Gonad pouches in a new clam-like monoplacophoran from the Silurian of Sweden

Linsley¹,

Peel²

1983

Lethaia

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“…The position of Sinuitina is not well understood and it has been interpreted both as an exogastric tergomyan (Starobogatov 1970;Runnegar & Jell 1976) and an endogastric gastropod (Knight 1945;Rollins et al 1971;Knight et al 1960;Wahlman 1992). Interpretation of possible muscle scars in the Devonian S. spinari Horný, 1963 from Bohemia is controversial and has not contributed towards resolving the taxonomic position of the genus (see Horný 1963b;Runnegar & Jell 1976;Berg-Madsen & Peel 1978). Starobogatov (1970) interpreted Sinuitopsis as an untorted mollusc, based on a functional interpretation of the median anterior and two umbilico-lateral sinuses.…”

Section: Introductionmentioning

confidence: 99%

Isostrophic molluscs (Tergomya and Gastropoda) from the Upper Ordovician of Norway

Ebbestad¹,

Yochelson²

2000

Norsk Geologisk Tidsskrift

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Middle Cambrian monoplacophorans from Bornholm and Australia, and the systematic position of the bellerophontiform molluscs

Cited by 43 publications

References 9 publications

Towards a phylogeny of gastropod molluscs: an analysis using morphological characters

Towards a phylogeny of gastropod molluscs: an analysis using morphological characters

Gonad pouches in a new clam-like monoplacophoran from the Silurian of Sweden

Isostrophic molluscs (Tergomya and Gastropoda) from the Upper Ordovician of Norway

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