Pelvic claspers confirm chondrichthyan-like internal fertilization in arthrodires

@article{Ahlberg2009PelvicCC,
  title={Pelvic claspers confirm chondrichthyan-like internal fertilization in arthrodires},
  author={Per Erik Ahlberg and Kate Trinajstic and Zerina Johanson and John Long},
  journal={Nature},
  year={2009},
  volume={460},
  pages={888-889}
}
Recent finds demonstrate that internal fertilization and viviparity (live birth) were more widespread in the Placodermi, an extinct group of armoured fishes, than was previously realized. Placoderms represent the sister group of the crown group jawed vertebrates (Gnathostomata), making their mode(s) of reproduction potentially informative about primitive gnathostome conditions. An ossified pelvic fin basipterygium discovered in the arthrodire Incisoscutum ritchiei was hypothesized to be… 

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Molecular development of chondrichthyan claspers and the evolution of copulatory organs

It is reported that clasper development from pelvic fins of male skates is controlled by hormonal regulation of the Sonic hedgehog (Shh) pathway, and it is shown that Shh signalling is necessary for maleClasper development and is sufficient to induce clasper cartilages in females.

New morphological information on, and species of placoderm fish Africanaspis (Arthrodira, Placodermi) from the Late Devonian of South Africa

There is some faunal overlap between the Waterloo Farm fossil site and faunas described from Strud in Belgium and Red Hill, Pennsylvania, in north America, supporting the concept of a more cosmopolitan vertebrate fauna in the Famennian than earlier in the Devonian.

A review of recent discoveries of exceptionally preserved fossil fishes from the Gogo sites (Late Devonian, Western Australia)

  • J. LongK. Trinajstic
  • Biology
    Earth and Environmental Science Transactions of the Royal Society of Edinburgh
  • 2017
Through their exceptional preservation of both hard and varied kinds of soft tissues, the Gogo fishes remain crucial for resolving key debates on the diversification, physiology, biomechanics and phylogenetic relationships of early gnathostomes.

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