False teeth: conodont-vertebrate phylogenetic relationships revisited

  title={False teeth: conodont-vertebrate phylogenetic relationships revisited},
  author={Susan Turner and Carole J. Burrow and Hans-Peter. Schultze and Alain Blieck and Wolf-Ernst Reif and Carl Buckner Rexroad and Pierre Bultynck and Godfrey S. Nowlan},
ABSTRACT An evidence-based reassessment of the phylogenetic relationships of conodonts shows that they are not “stem” gnathostomes, nor vertebrates, and not even craniates. A significant group of conodont workers have proposed or accepted a craniate designation for the conodont animal, an interpretation that is increasingly becoming established as accepted “fact”. Against this prevailing trend, our conclusion is based on a revised analysis of traditional morphological features of both discrete… 
The origin of conodonts and of vertebrate mineralized skeletons
The hypothesis that teeth evolved before jaws and the inside-out hypothesis of dental evolution must be rejected; teeth seem to have evolved through the extension of odontogenic competence from the external dermis to internal epithelium soon after the origin of jaws.
Palaeontology: Inside-out turned upside-down
  • P. Janvier
  • Geography, Environmental Science
  • 2013
The data suggest that the last common ancestor of Conodonta and jawed vertebrates lacked mineralized skeletal tissues, suggesting an 'inside out' evolutionary model in which teeth originated in the mouth.
Comprehending conodonts
  • M. Barham
  • Environmental Science, Geography
  • 2015
Conodonts were small, thin, elongate jawless creatures that were a common component of the marine fauna from the late Cambrian, throughout the Palaeozoic and into the Triassic. For the majority of
Tooth-Like Scales in Early Devonian Eugnathostomes and the ‘Outside-In’ Hypothesis for the Origins of Teeth in Vertebrates
Transitional forms of ischnacanthid acanthodians from the Man On The Hill locality in the Mackenzie Mountains of Canada provide the first unequivocal example of such transitional forms in an Early Devonian (Lochkovian) vertebrate assemblage.
Hagfish from the Cretaceous Tethys Sea and a reconciliation of the morphological–molecular conflict in early vertebrate phylogeny
By addressing nonindependence of characters, phylogenetic analyses recovered hagfish and lampreys in a clade of cyclostomes (congruent with the cyclostome hypothesis) using only morphological data, which potentially resolve the morphological–molecular conflict at the base of the Vertebrata.
Retention of fish-like odontode overgrowth in Permian tetrapod dentition supports outside-in theory of tooth origins
It is shown that, unlike the well-known one-to-one replacement patterns of marginal dentition, the palatal dentition of the early Permian tetrapods, including the dissorophoid amphibian Cacops and the early reptile Captorhinus, is overgrown by a new layer of bone to which the newest teeth are then attached.
A 26408 : Evolutionary origin of teeth
The available evidence supports an origin of teeth through extension of odontogenic competence from the external dermis to the oropharynx.
Old, new and new-old concepts about the evolution of teeth
New findings support the traditional outside-in hypothesis: the mineralized elements of conodonts are not teeth, and the oral cusps in basal placoderms are true teeth.
Ultrastructure reveals ancestral vertebrate pharyngeal skeleton in yunnanozoans.
Examining additional specimens in previously unexplored techniques found evidence that yunnanozoan branchial arches consist of cellular cartilage with an extracellular matrix dominated by microfibrils, a feature hitherto considered specific to vertebrates.


Conodont anatomy, chordate phylogeny and vertebrate classification
Fossilized soft-tissue evidence indicates that conodonts possessed eyes, extrinsic eye muscles, a notochord, myomeres, a differentiated tail with fin radiais, possible otic capsules and possible branchial structures, and exhaustive analysis of a more complete character-set strongly supports the hypothesis that conODonts are more derived than hagfish.
Soft anatomy and the affinities of conodonts
The available soft tissue evidence suggests that conodonts are best regarded as the sister group of the craniates.
Conodonts, Calcichordates and the Origin of Vertebrates
Soft-part preservation of conodont animals, with V-shaped myomeres and a notochord, shows that they were segmented chordates, while probable eyes and teeth suggest that they was already on the vertebrate side.
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.
Fossil sister group of craniates: Predicted and found
Haikouella agrees so closely with recent predictions about pre‐craniates that the difficult problem of craniate origins is nearly solved.
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.
Microstructural variation in conodont enamel is a functional adaptation
  • P. Donoghue
  • Geography, Materials Science
    Proceedings of the Royal Society of London. Series B: Biological Sciences
  • 2001
The enamel of conodonts evolved in response to changes in dental function and differentiation of the microstructural layer into a number of enamel types and can be linked to dental occlusion, heterodonty, a permanent dentition, enamel thickness and, probably above all, the small size of the dental elements.
The hypothesis that conodonts are vertebrates rests solely on evidence of soft tissue anatomy, and it is found that the range of microstructural variation observed hitherto was already apparent among plesiomorphic euconodronts.
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.
Head and backbone of the Early Cambrian vertebrate Haikouichthys
Phylogenetic analysis indicates that Haikouichthys somewhat resembles the ammocoete larva of modern lampreys, this is because of shared general craniate characters; adult lampreys and hagfishes (the cyclostomes if monophyletic) are probably derived in many respects.