Hagfish (cyclostomata, vertebrata): Searching for the ancestral developmental plan of vertebrates

  title={Hagfish (cyclostomata, vertebrata): Searching for the ancestral developmental plan of vertebrates},
  author={Shigeru Kuratani and Kinya G Ota},
The phylogenetic position of the hagfish remains enigmatic. In contrast to molecular data that suggest monophyly of the cyclostomes, several morphological features imply a more ancestral state of this animal compared with the lampreys. To resolve this question requires an understanding of the embryology of the hagfish, especially of the neural crest. The early development of the hagfish has long remained a mystery. We collected a shallow‐water‐dwelling hagfish, Eptatretus burgeri, set up an… 

Evolution of the Vertebrate Cranium: Viewed from Hagfish Developmental Studies

The development of the hagfish chondrocranium in light of the cyclostome pattern is summarized, an updated comparison of the cycle is presented, and several aspects of the evolution andDevelopment of the vertebrate skull are discussed.

Late Development of Hagfish Vertebral Elements

It is proposed that hagfishes and gnathostomes share conserved developmental mechanisms not only in their somite differentiation, but also in chondrogenesis of their vertebral elements.

An Advanced Filter-Feeder Hypothesis for Urochordate Evolution

An advanced filter-feeder hypothesis is presented, in which, although the taxonomic position of larvaceans is enigmatic, it is argued that among urochordates, free-living larvACEans are basal, while sessile ascidians are derived.

Functional genetic analysis in a jawless vertebrate, the sea lamprey: insights into the developmental evolution of early vertebrates

How genetic analysis of embryogenesis in the sea lamprey has provided insight into the origin and evolution of developmental-genetic programs in vertebrates is described.

Phylogeny and evolutionary history of the amniote egg

Except for the amnion, chorioallantois, and amniote type of eggshell, these features evolved convergently in almost all major clades of aquatic vertebrates possibly in response to selective factors such as egg predation, hostile environmental conditions for egg development, or to adjust hatching of young to favorable season.

Cephalic muscles of Cyclostomes (hagfishes and lampreys) and Chondrichthyes (sharks, rays and holocephalans): comparative anatomy and early evolution of the vertebrate head muscles

This paper provides an updated overview of the anatomy, homologies and evolution of cyclostome and chondrichthyan cephalic muscles, with osteichthyans as primary comparative taxa and infers plesiomorphic conditions for vertebrates and gnathostomes.

The Nervous Systems of Jawless Vertebrates

Evolutionary and Developmental Associations of Neural Crest and Placodes in the Vertebrate Head: Insights From Jawless Vertebrates

The developmental mechanisms and genetics of neural crest and placodes in both jawed and jawless vertebrates are summarized and comparisons with jawed vertebrates can provide insights into the causes and consequences of this event in early vertebrate evolution are discussed.

Overview of the transcriptome profiles identified in hagfish, shark, and bichir: current issues arising from some nonmodel vertebrate taxa.

  • M. TakechiM. Takeuchi S. Kuratani
  • Biology, Environmental Science
    Journal of experimental zoology. Part B, Molecular and developmental evolution
  • 2011
How hagfishes, sharks, and bichirs contribute to the authors' understanding of vertebrate evolution is discussed, the current status of the publicly available sequence data for these three taxa is reviewed, and a newly constructed database, designated the "Vertebrate TimeCapsule", is introduced.

Genome Duplication in Early Vertebrates: Insights from Agnathan Cytogenetics

Comparison of cytogenetic data and phylogenetic relationships among agnathans and gnathostomes seems to support the hypothesis that 1R and 2R occurred before the evolutionary divergence between jawless and jawed vertebrates.



Hagfish embryology with reference to the evolution of the neural crest

It is proposed that the neural crest emerged as a population of de-epithelialized migratory cells in a common vertebrate ancestor, and it is suggested that the possibility of classical and molecular embryology in hagfish opens up new approaches to clarifying the evolutionary history of vertebrates.

Ontogeny of the head of the Pacific hagfish (Eptatretus stouti, Myxinoidea): development of the lateral line system.

  • H. WichtR. Northcutt
  • Biology
    Philosophical transactions of the Royal Society of London. Series B, Biological sciences
  • 1995
It is found that an embryonic lateral line system is present in hagfishes, and that the grooves of adult hagFishes in all probability derive from lateral line placodes, which is a primitive character of craniates.

The History of Scientific Endeavors Towards Understanding Hagfish Embryology

This review summarizes the importance of hagfish embryology from a phylogenetic perspective, and the history of attempts to obtain hag fish eggs and embryos, and discusses the future prospects for obtaining embryological material, both from the wild and in the laboratory.

The neural crest

Monophyly of Lampreys and Hagfishes Supported by Nuclear DNA–Coded Genes

Cl cloning and sequencing of the four nuclear DNA–coded single-copy genes encoding the triose phosphate isomerase, calreticulin, and the largest subunit of RNA polymerase II and III were conducted, and it was shown that all the five proteins prefer the monophyletic tree of cyclostomes, which significantly supports the cyclostome monophyly at the level of ±1 SE.

Molecular phylogeny of early vertebrates: monophyly of the agnathans as revealed by sequences of 35 genes.

This work uses the sequences of 35 nuclear protein-encoding genes to provide definitive evidence for the monophyly of the Agnatha (jawless vertebrates, a group encompassing the hagfishes and lampreys).

Bayesian Phylogenetic Analysis Supports Monophyly of Ambulacraria and of Cyclostomes

Using robust Bayesian statistical analysis of 18S ribosomal DNA, mitochondrial genes and nuclear protein-coding DNA, strong support is found for a hemichordate-echinoderm clade and for monophyly of the cyclostomes.

Primitive versus derived traits in the developmental program of the vertebrate head: views from cyclostome developmental studies.

  • S. KurataniK. Ota
  • Biology
    Journal of experimental zoology. Part B, Molecular and developmental evolution
  • 2008
It is demonstrated that a set of embryonic features can be coupled or decoupled during evolution and development, and the importance of "developmental burden" in determining the sequential order of changes through evolution is stressed.

Early Development of the Hagfish Pituitary Gland: Evidence for the Endodermal Origin of the Adenohypophysis

Synopsis. The adenohypophysis in early head fold stage hagfish embryos is at first a distinct differentiated thickening ofthe archenteric roof where it contacts the developing infundibular portion of

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.