Abstract
Detailed histological investigations have shed new light on the nature of Pseudooneotodus Drygant, 1974 (?Arenig/Llanvirn - Emsian). The genus has generally been interpreted as a conodont and is represented by squat phosphatic cones. These conodont elements show a differentiation into a lamellar cap, indistinguishable from vertebrate enamel, which is underlain by a spherulitic basal tissue with several characters indicative of dentine. The presence of these two issues in the elements of a conodont argues persuasively for the vertebrate classification of the clade, and illustrates that at least some conodonts have a hard tissue complex which is histologically indistinguishable from those of other primitive vertebrates. These observations have potentially important implications for conodont classification and the stratigraphic first appearances of vertebrate hard tissues.
| Original language | English |
|---|---|
| Pages (from-to) | 47-57 |
| Number of pages | 11 |
| Journal | Zoological Journal of the Linnean Society |
| Volume | 118 |
| Issue number | 1 |
| DOIs | |
| Publication status | Published - Sept 1996 |
Bibliographical note
Funding Information:I would like to thank Moya Smith (UMDS, Guy’s Hospital) and Paul Smith (University of Birmingham) for their comments and advice during the course of this study. In addition, Howard Armstrong (University of Durham), Jim Barrick (Texas Tech. University), Jerzy Dzik (Warsaw), Lennart Jeppsson (Lund University), Martha Richter (Porto Alegre), Graham Young (Manitoba) and Simon Tull (CASP, Cambridge) are thanked for providing many specimens and information, without which this study would not have been possible. Peter Forey (Natural History Museum), Mark Purnell (University of Leicester) and David Elliott (University of Northern Arizona, Flagstaff) are thanked for their critical reviews of the manuscript, whilst Fi McKie helped with proof reading. Technical assistance was provided by Angus Parker, Aruna Mistry, Ken Brady and Trevor Whitfield. This work was initiated whilst the author was in receipt of a Natural Environment Research Council studentship (Grant Ref. GT4/88/GS 139) based at the Universities of Newcastle upon Tyne and Durham; further work has been funded by NERC research grant (GR3 8543) which is gratefully acknowledged.
Keywords
- Conodonts
- Dentine
- Enamel
- Neural crest
- Ordovician
- Vertebrates
ASJC Scopus subject areas
- Ecology, Evolution, Behavior and Systematics
- Animal Science and Zoology