Taxonomy, morphology and phylogeny of Late Cretaceous spirulid coleoids (Cephalopoda) from Greenland and Canada
Abstract: Groenlandibelus rosenkrantzi from the Maastrichtian of Greenland has long been thought to constitute an early representative of spirulid coleoids. This study shows that this view must be reassessed, at least in part. A re‐investigation of the types and of material recorded subsequently has...
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crwiley:10.1111/j.1475-4983.2011.01125.x 2024-06-02T08:07:27+00:00 Taxonomy, morphology and phylogeny of Late Cretaceous spirulid coleoids (Cephalopoda) from Greenland and Canada FUCHS, DIRK KEUPP, HELMUT TRASK, PAT TANABE, KAZUSHIGE 2012 http://dx.doi.org/10.1111/j.1475-4983.2011.01125.x https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fj.1475-4983.2011.01125.x https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1475-4983.2011.01125.x en eng Wiley http://onlinelibrary.wiley.com/termsAndConditions#vor Palaeontology volume 55, issue 2, page 285-303 ISSN 0031-0239 1475-4983 journal-article 2012 crwiley https://doi.org/10.1111/j.1475-4983.2011.01125.x 2024-05-03T11:25:59Z Abstract: Groenlandibelus rosenkrantzi from the Maastrichtian of Greenland has long been thought to constitute an early representative of spirulid coleoids. This study shows that this view must be reassessed, at least in part. A re‐investigation of the types and of material recorded subsequently has revealed that none of these specimens is conspecific with the holotype of G. rosenkrantzi . Cyrtobelus birkelundae gen. nov, sp. nov. differs from the type of G. rosenkrantzi in having lower chambers and in lacking an apically elongated sheath. The longiconic phragmocone of G. rosenkrantzi has more features in common with the presumed spirulid genus Naefia . A specimen described in detail by J. A. Jeletzky in the mid 1960s as ‘ G. rosenkrantzi ’ is designated holotype of C. birkelundae sp. nov., which means that internal phragmocone features are still unknown in G. rosenkrantzi. Cyrtobelus hornbyense gen. nov, sp. nov. from the Campanian of western Canada constitutes the first record of early spirulids from the northeast Pacific, being based on seventeen extraordinarily well‐preserved phragmocones. This species differs from C. birkelundae sp. nov. only in the width of the siphuncular tube. The presence of a caecum, a nacre‐less conotheca that represents the continuation of the protoconch conotheca, conothecal flaps that anchor the mural parts of the septa, and a thin investment‐like sheath are characters shared only with Recent Spirula. In particular, the unusual protoconch architecture of Cyrtobelus gen. nov. challenges a phylogenetic origin within bactritoid‐like coleoids. Article in Journal/Newspaper Greenland Wiley Online Library Canada Greenland Pacific Palaeontology 55 2 285 303 |
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Wiley Online Library |
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English |
description |
Abstract: Groenlandibelus rosenkrantzi from the Maastrichtian of Greenland has long been thought to constitute an early representative of spirulid coleoids. This study shows that this view must be reassessed, at least in part. A re‐investigation of the types and of material recorded subsequently has revealed that none of these specimens is conspecific with the holotype of G. rosenkrantzi . Cyrtobelus birkelundae gen. nov, sp. nov. differs from the type of G. rosenkrantzi in having lower chambers and in lacking an apically elongated sheath. The longiconic phragmocone of G. rosenkrantzi has more features in common with the presumed spirulid genus Naefia . A specimen described in detail by J. A. Jeletzky in the mid 1960s as ‘ G. rosenkrantzi ’ is designated holotype of C. birkelundae sp. nov., which means that internal phragmocone features are still unknown in G. rosenkrantzi. Cyrtobelus hornbyense gen. nov, sp. nov. from the Campanian of western Canada constitutes the first record of early spirulids from the northeast Pacific, being based on seventeen extraordinarily well‐preserved phragmocones. This species differs from C. birkelundae sp. nov. only in the width of the siphuncular tube. The presence of a caecum, a nacre‐less conotheca that represents the continuation of the protoconch conotheca, conothecal flaps that anchor the mural parts of the septa, and a thin investment‐like sheath are characters shared only with Recent Spirula. In particular, the unusual protoconch architecture of Cyrtobelus gen. nov. challenges a phylogenetic origin within bactritoid‐like coleoids. |
format |
Article in Journal/Newspaper |
author |
FUCHS, DIRK KEUPP, HELMUT TRASK, PAT TANABE, KAZUSHIGE |
spellingShingle |
FUCHS, DIRK KEUPP, HELMUT TRASK, PAT TANABE, KAZUSHIGE Taxonomy, morphology and phylogeny of Late Cretaceous spirulid coleoids (Cephalopoda) from Greenland and Canada |
author_facet |
FUCHS, DIRK KEUPP, HELMUT TRASK, PAT TANABE, KAZUSHIGE |
author_sort |
FUCHS, DIRK |
title |
Taxonomy, morphology and phylogeny of Late Cretaceous spirulid coleoids (Cephalopoda) from Greenland and Canada |
title_short |
Taxonomy, morphology and phylogeny of Late Cretaceous spirulid coleoids (Cephalopoda) from Greenland and Canada |
title_full |
Taxonomy, morphology and phylogeny of Late Cretaceous spirulid coleoids (Cephalopoda) from Greenland and Canada |
title_fullStr |
Taxonomy, morphology and phylogeny of Late Cretaceous spirulid coleoids (Cephalopoda) from Greenland and Canada |
title_full_unstemmed |
Taxonomy, morphology and phylogeny of Late Cretaceous spirulid coleoids (Cephalopoda) from Greenland and Canada |
title_sort |
taxonomy, morphology and phylogeny of late cretaceous spirulid coleoids (cephalopoda) from greenland and canada |
publisher |
Wiley |
publishDate |
2012 |
url |
http://dx.doi.org/10.1111/j.1475-4983.2011.01125.x https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fj.1475-4983.2011.01125.x https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1475-4983.2011.01125.x |
geographic |
Canada Greenland Pacific |
geographic_facet |
Canada Greenland Pacific |
genre |
Greenland |
genre_facet |
Greenland |
op_source |
Palaeontology volume 55, issue 2, page 285-303 ISSN 0031-0239 1475-4983 |
op_rights |
http://onlinelibrary.wiley.com/termsAndConditions#vor |
op_doi |
https://doi.org/10.1111/j.1475-4983.2011.01125.x |
container_title |
Palaeontology |
container_volume |
55 |
container_issue |
2 |
container_start_page |
285 |
op_container_end_page |
303 |
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1800752540283830272 |