Conodont affinity and chordate phylogeny

  title={Conodont affinity and chordate phylogeny},
  author={Philip C. J. Donoghue and Peter L. Forey and Richard J. Aldridge},
  journal={Biological Reviews},
Current information on the conodonts Clydagnathus windsorensis (Globensky) and Promissum pulchrum Kovács-Endrödy, together with the latest interpretations of conodont hard tissues, are reviewed and it is concluded that sufficient evidence exists to justify interpretation of the conodonts on a chordate model. [] Key Method A new phylogenetic analysis is undertaken, consisting of 17 chordate taxa and 103 morphological, physiological and biochemical characters; conodonts are included as a primary taxon.

False teeth: conodont-vertebrate phylogenetic relationships revisited

An evidence-based reassessment of the phylogenetic relationships of conodonts shows that they are not “stem” gnathostomes, nor vertebrates, and not even craniates, which supports neither a vertebrate nor a craniate relationship for conodons.

A Phylogeny for Heterostraci (stem-gnathostomes)

The results presented here are the first phylogenetic hypotheses of heterostracan relationships and it is hoped a first step into an accurate interpretation of character evolution and polarity in this crucial episode of vertebrate evolution.

Functional assessment of morphological homoplasy in stem-gnathostomes

These results confirm that a number of the characters typically used to infer the evolutionary relationships among galeaspids, osteostracans and jawed vertebrates are convergent in nature, potentially obscuring understanding of the assembly of the gnathostome bodyplan.


Abstract Conodonts were mostly small, elongate, eel-shaped marine animals that inhabited a variety of environments in Paleozoic and Triassic seas. Although long enigmatic, conodonts are now regarded

The characters of Palaeozoic jawed vertebrates

A clearly stated hierarchy of synapomorphies covering the jaw-bearing stem gnathostomes and osteichthyan and chondrichthyan stem groups is provided and a proposed synapomorphy scheme is used to evaluate the status of the problematic fossil groups Acanthodii and Placodermi.

Panderodus from the Waukesha Lagerstätte of Wisconsin, USA: a primitive macrophagous vertebrate predator

Overall, the specimen shows that Panderodus was a macrophagous feeder and provides an insight into the functional anatomy of early vertebrate predation.

Exploring phylogenetic relationships of Pteraspidiformes heterostracans (stem-gnathostomes) using continuous and discrete characters

It is shown that many ‘classic’ Pteraspidiformes clades hold true under different coding methods, with the implied weighting of discrete characters and inclusion of continuous characters giving very similar topologies.

The interrelationships of ‘complex’ conodonts (Vertebrata)

It is proposed that cladistics provides an appropriate methodology to test existingschemes of classification and in which to explore the evolutionary relationships of conodonts.

Fossils, histology, and phylogeny: Why conodonts are not vertebrates

It is considered that conodont hard tissues and several other anatomical structures in Conodonts are not homologous with those of vertebrates, and the phylogenetic relationships of conodons and chordates should be extended to include non-chordate taxa.

Morphometric analysis of taxonomy, evolution, autecology and homology in ozarkodinid conodonts

This study has quantified evolutionary rates in conodonts for the first time and the methods and results presented here have the potential to catalyse comprehensive morphometric analysis of conodons using these widely applicable protocols.



Conodont palaeobiology: recent progress and unsolved problems

  • S. Morris
  • Environmental Science, Geography
  • 1989
Some aspects of conodont palaeobiology reviewed here include mode of life and possible migration, reproduction and genetics, and palaeopathology, which rely almost exclusively on the study ofConodont elements.


It is suggested that Pogonophora, including the Vestimentifera, is the sister group of the Radialia and both groups belong to the Enterocoela, a scenariolike narrative of character transformations, from the tubicolous annelids to the vertebrates.

A neontological interpretation of conodont elements based on agnathan cyclostome tooth structire function, and development

It is provisionally suggested that the primary organic matrix of conodont elements could be keratin and/or keratin-related molecules, and that individual conodront elements could represent shed tooth coverings, contrary to several paradigms of orthodox conodentology.


Palaeontological studies indicate that the conodont‐bearing animals were adapted to a wide variety of shallow‐water, marine environments, and the arrangement, form, number, chemical composition and faunal associations of conODonts do not appear to favour the theories of their crustacean or molluscan origin.

The structure of some Middle Cambrian conodonts, and the early evolution of conodont structure and function

A proposed model of the early evolution of conodonts involves that elements of the Conodontiformes were completely engulfed in epithelial pockets, which enabled them to grow holoperipherally and thus to assume more complex shapes that could be retained during growth.

The anatomy of conodonts

Ten specimens from the Carboniferous Granton shrimp bed of Edinburgh, Scotland, provide the most complete record of conodont anatomy, with evidence of incomplete preservation of ventral soft parts, at least at the anterior end of the specimens.

Decay of Branchiostoma: implications for soft‐tissue preservation in conodonts and other primitive chordates

Decay experiments on the cephalochordate Branchiostoma lanceolatum (‘amphioxus’) demonstrate that the most decay resistant structures are the notochord sheath and the cartilaginous rods which support the gill bars, and cast light on the interpretation of a number of primitive fossil chordates.

Yunnanozoon and the ancestry of chordates

The oldest known chordate, Yunnanozoon lividum Hou et al. 1991, from the Chengiang Lagerstatte of Yunnan shows several features in its anatomy that had not been expected to occur at this stage of


  • J. Maisey
  • Biology
    Cladistics : the international journal of the Willi Hennig Society
  • 1986
A cladistic analysis of chordates is presented, based on some 320 nested characters, thereby reopening the possibility of a closer relationship between tetrapods and osteolepiform rhipidistians.

28S and 18S rDNA sequences support the monophyly of lampreys and hagfishes.

Moderate to very strong support is provided for the monophyly of the cyclostomes in lampreys plus hagfishes and the currently accepted hypothesis of a lamprey-gnathostome clade is moderately rejected by the Kishino-Hasegawa test and resoundingly rejected by parametric bootstrap tests.