Non-ammocoete larvae of Palaeozoic stem lampreys.

  title={Non-ammocoete larvae of Palaeozoic stem lampreys.},
  author={Tetsuto Miyashita and Robert W. Gess and Kristen Tietjen and Michael I. Coates},
Ammocoetes-the filter-feeding larvae of modern lampreys-have long influenced hypotheses of vertebrate ancestry1-7. The life history of modern lampreys, which develop from a superficially amphioxus-like ammocoete to a specialized predatory adult, appears to recapitulate widely accepted scenarios of vertebrate origin. However, no direct evidence has validated the evolutionary antiquity of ammocoetes, and their status as models of primitive vertebrate anatomy is uncertain. Here we report larval… 

Thyroid and endostyle development in cyclostomes provides new insights into the evolutionary history of vertebrates

This work shows that the thyroid gland of hagfish undergoes direct development from the ventrorostral pharyngeal endoderm, where the previously described endostyle-like primordium was not found, and challenges the plesiomorphic status of the lamprey endstyle and proposes an alternative hypothesis where the lampreys endostyles could be obtained secondarily in crown lampreys.

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

The Evolution of the Spiracular Region From Jawless Fishes to Tetrapods

The first confirmed example of a complete spiracular gill in any vertebrate is presented, in the galeaspid (jawless stem gnathostome) Shuyu, and comparisons with two other groups of jawless stem Gnathostomes indicate that they also probably possessed full-sized Spiracular gills and that this condition may thus be primitive for the gnathOSTome stem group.

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.

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.

Slippery when wet: cross-species transmission of divergent coronaviruses in bony and jawless fish and the evolutionary history of the Coronaviridae

Despite possessing a phylogenetic history that likely spans the entire history of the vertebrates, coronavirus evolution has been characterised by relatively frequent cross-species transmission, particularly in hosts that reside in aquatic habitats.

On an unknown lamprey holotype (Petromyzon macrostomus Burmeister 1868) and the genus Exomegas Gill 1883 from South America.

Preliminary results resolve a century-long taxonomic uncertainty and foster a nomenclatural arrangement for a Southern Hemisphere lamprey genus.

Reconstructing the ancestral vertebrate brain using a lamprey neural cell type atlas

The ancestral vertebrate brain was likely devoid of cerebellar cell types and oligodendrocytes (myelinating cells); the data suggest that the latter emerged from astrocyte-like evolutionary precursors on the jawed vertebrate lineage.

Hagfish to Illuminate the Developmental and Evolutionary Origins of the Vertebrate Retina

This finding of eye growth late into hagfish ontogeny is unexpected given the degenerate eye phenotype and further studies dissecting retinal neurogenesis in jawless vertebrates would allow for comparison of the mechanisms of retinal development between cyclostome and gnathostome eyes and provide insight into the evolutionary origins of the vertebrate eye.



The evolution of lamprey (Petromyzontida) life history and the origin of metamorphosis

A review synthesizes findings and concludes that the ancestral lamprey life cycle followed a direct development, suggesting that the larval period was short and relatively limited if present at all, but that the juvenile included modern larval traits.

A lamprey from the Devonian period of South Africa

A marine/estuarine fossil lamprey from the Famennian (Late Devonian) of South Africa is reported, the identity of which is established easily because many of the key specializations of modern forms are already in place, evidence that agnathans close to modern lampreys had evolved before the end of the Devonian period.

Tunicates and not cephalochordates are the closest living relatives of vertebrates

It is shown that phylogenetic analyses of the genome sequencing of the appendicularian Oikopleura dioica provide compelling evidence that tunicates, and not cephalochordates, represent the closest living relatives of vertebrates.

Discovery of fossil lamprey larva from the Lower Cretaceous reveals its three-phased life cycle

The discovery of exceptionally preserved premetamorphic and metamorphosing larvae of the fossil lamprey Mesomyzon mengae from the Lower Cretaceous of Inner Mongolia, China are reported, indicating the three-phased life cycle in lampreys emerged essentially in their present mode no later than the Early Cret Jurassic.

The Long-Rostrumed Elasmobranch Bandringa Zangerl, 1969, and Taphonomy Within a Carboniferous Shark Nursery

A new reconstruction of Bandringa incorporates several previously unreported features, including ventrally directed jaws, stellate squamation, a branched lateral line, and fin spines bearing smooth costae, which provide a more complete picture of hard- and soft-tissue anatomy than resident taxa from a single deposit.

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.

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.

Estuarine fish and tetrapod evolution: insights from a Late Devonian (Famennian) Gondwanan estuarine lake and a southern African Holocene equivalent

  • R. GessA. Whitfield
  • Environmental Science
    Biological reviews of the Cambridge Philosophical Society
  • 2020
Correlation of tetrapods (and elpistostegids) with fish nursery areas in the Late Devonian lends strong support to this hypothesis, suggesting that adaptations permitting improved access to the abundant juvenile fish within the littoral zone of estuarine lakes and continental water bodies may have been pivotal in the evolution of Tetrapods.

Theory on the evolutionary history of lamprey metamorphosis: role of reproductive and thyroid axes.

  • J. YousonS. Sower
  • Biology
    Comparative biochemistry and physiology. Part B, Biochemistry & molecular biology
  • 2001