A Paleozoic stem hagfish Myxinikela siroka — revised anatomy and implications for evolution of the living jawless vertebrate lineages

  title={A Paleozoic stem hagfish Myxinikela siroka — revised anatomy and implications for evolution of the living jawless vertebrate lineages},
  author={Tetsuto Miyashita},
  journal={Canadian Journal of Zoology},
Hagfishes and lampreys comprise cyclostomes, the earliest branching and sole surviving clade of the once diverse assemblage of jawless crown-group vertebrates. Lacking mineralized skeletons, both o... 
Comparative Approaches in Vertebrate Cartilage Histogenesis and Regulation: Insights from Lampreys and Hagfishes
A model through which these mesenchymal connective tissues acquired distinct histologies and that histological flexibility in cartilage existed in the last common ancestor of modern vertebrates is suggested.
A new look at the Cretaceous Lamprey Mesomyzon Chang, Zhang & Miao, 2006 from the Jehol Biota
ABSTRACT Lampreys, one of the remaining two living jawless vertebrates, carry great weight in the study of vertebrate evolution. They have a long history dating back to the Devonian but left a scarce
Vision and retina evolution: How to develop a retina


Relationships of Living and Fossil Hagfishes
The fossil record of agnathans now includes representatives of the myxinoids (hagfish) as well as lampreys, and Fossils of other jawless fishes, both skeletal and soft-bodied forms, are discussed.
First Fossil Hagfish (Myxinoidea): A Record from the Pennsylvanian of Illinois
  • D. Bardack
  • Geography, Environmental Science
  • 1991
A fossil hagfish (Myxinoidea), a new genus from the Pennsylvanian, shows tentacles, structures of the head skeleton and internal organs, and it is quite similar to its recent relatives.
Early Jawless Vertebrates and Cyclostome Origins
  • P. Janvier
  • Geography, Environmental Science
    Zoological science
  • 2008
The anatomy and physiology of lampreys and hagfishes are so different that it is difficult to reconstruct an ancestral morphotype of the cyclostomes, assuming that they are a clade, and there is no clear evidence of any fossil taxon that is neither a fossil hagfish nor a fossil lamprey, but would be more closely related to the Cyclostomes than to the gnathostomes.
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.
Feeding mechanisms as evidence for cyclostome monophyly
The feeding mechanisms of lampreys and hagfish are reviewed, and it is concluded that the cyclostomes constitute a monophyletic group, the sister-group of the gnathostomes.
Decay of vertebrate characters in hagfish and lamprey (Cyclostomata) and the implications for the vertebrate fossil record
An experimental analysis of decay of vertebrate characters based on the extant jawless vertebrates (Lampetra and Myxine) provides a framework for the interpretation of the anatomy of soft-bodied fossil vertebrates and putative cyclostomes, and a context for reading the fossil record of non-biomineralized vertebrates.
Craniofacial development of hagfishes and the evolution of vertebrates
The craniofacial development of a series of staged hagfish embryos is described, which shows that their adenohypophysis arises ectodermally, consistent with the molecular phylogenetic data and identifies a pan-cyclostome pattern, one not shared by jawed vertebrates.
Synchrotron-aided reconstruction of the conodont feeding apparatus and implications for the mouth of the first vertebrates
The geometrical analysis of exceptional three-dimensionally preserved clusters of oro-pharyngeal elements of the Early Triassic Novispathodus suggests the presence of a pulley-shaped lingual cartilage similar to that of extant cyclostomes within the feeding apparatus of euconodonts (“true” conodontS).
First Fossil Lamprey: A Record from the Pennsylvanian of Illinois
A fossil record of lampreys has previously been unknown, but a new genus demonstrates the presence of this group in the Pennsylvanian, and the absence of hagfish characters in the fossil supports the view that the common ancestor of Lampreys and hagfishes lived prior to thePennsylvanian.
Development of the Chondrocranium in Hagfishes, with Special Reference to the Early Evolution of Vertebrates
It is shown that the hagfish and lamprey chondrocrania can be compared perfectly at the level of modules corresponding to the craniofacial primordia constituting the cyclostome morphotype and its diversification in early vertebrate evolution.