Conodont anatomy, chordate phylogeny and vertebrate classification
1998; Wiley; Volume: 31; Issue: 3 Linguagem: Inglês
10.1111/j.1502-3931.1998.tb00509.x
ISSN1502-3931
AutoresPhilip C. J. Donoghue, Mark A. Purnell, Richard J. Aldridge,
Tópico(s)Evolution and Paleontology Studies
ResumoInterpretations of conodont anatomy and affinity continue to generate controversy. 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. Indirect evidence suggests a differentiated brain and cartilaginous head skeleton. The multi-component phosphatic tissue complexes of the conodont feeding apparatus cannot be compared to the amorphous apatite of extant agnathan otoliths. By limiting cladistic analysis to a restricted selection of these characters the hypothesis that conodonts are a sister group of the clade comprising extant hagfish, lampreys and gnathostomes can be supported. However, exhaustive analysis of a more complete character-set strongly supports the hypothesis that conodonts are more derived than hagfish. From a taxonomic perspective, these two hypotheses have no effect on how conodonts should be classified. Whether they are a stem group (the former hypothesis) or part of the crown group (the latter), conodonts are clearly part of the total group Vertebrata (=Craniata).
Referência(s)