Logo: to the web site of Uppsala University

uu.sePublications from Uppsala University
Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
The Placoderm Romundina and the Origin of the Gnathostome Face
Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
Muséum National D'Histoire Naturelle, Paris, France. (Département Histoire de la Terre)
European Synchrotron Radiation Facility, Grenoble, France.
Show others and affiliations
2013 (English)Conference paper, Oral presentation with published abstract (Refereed)
Abstract [en]

Facial anatomy differs fundamentally between extant jawless and jawed vertebrates (cyclostomes and gnathostomes). Cyclostomes have a median nasohypophysial duct; gnathostomes have separate nasal sacs opening externally, and a palatal hypophysis. Premandibular crest cells migrate forwards either side of the nasohypophysial placode to form the upper lip in cyclostomes, but between the hypophysial and nasal placodes to form the trabecular region in gnathostomes1,2. Supraoptic neural crest remains posterior to the nasohypophysial duct in cyclostomes but moves forward to create the nasal capsules of gnathostomes1,2. In cyclostomes the telencephalon is much shorter than in gnathostomes and the hypophysis is relatively anterior. The galeaspid Shuyu, a 430 million year old jawless vertebrate, partly bridges the gap between these facial architectures3. Shuyu has a nasohypophysial duct, short telencephalon, and anteriorly oriented hypophysis, but the nasal sacs and hypophysis are separated by a rudimentary trabecul. Here we present the placoderm Romundina, a 415 million year old jawed vertebrate that represents a further transitional step. Its cranial cavity is similar to that of Shuyu, with an anteriorly directed hypophysis and very short telencephalon. The trabecular region is exceptionally long and wide whereas the nasal capsule (demarcated by a fissure) is small and located far behind the tip of the snout. The upper jaw articulates with the side of the trabecular region to its anterior end, without contacting the nasal capsule. We interpret these features as uniquely primitive among gnathostomes. The premandibular crest of Romundina formed a trabecular region, but like the upper lip of cyclostomes and Shuyu it was a large structure reaching the tip of the snout. The position of the nasal capsule suggests that the supraoptic crest had not migrated forwards. We suggest that during the creation of the gnathostome face, separation of the nasal and hypophysial placodes was followed by loss of the nasohypophysial duct, with lengthening of the telencephalon and migration of the nasal capsules to the snout tip as the final step.

 

1. Kuratani, S. et al. Phil. Trans. R. Soc. Lond. B 356, 1615-1632 (2001).

2. Kuratani, S. et al. Nature (in press, doi:10.1038/nature11794).

3. Gai, Z. et al. Nature 476, 324-327 (2011).

Place, publisher, year, edition, pages
2013.
National Category
Evolutionary Biology
Identifiers
URN: urn:nbn:se:uu:diva-190724OAI: oai:DiVA.org:uu-190724DiVA, id: diva2:584059
Conference
The Making of a Vertebrate, CDB Symposium, Kobe, Japan, March 4-6,2013
Funder
EU, European Research Council, 233111Available from: 2013-01-08 Created: 2013-01-08 Last updated: 2022-01-28Bibliographically approved

Open Access in DiVA

No full text in DiVA

Authority records

Sanchez, SophieAhlberg, Per

Search in DiVA

By author/editor
Dupret, VincentSanchez, SophieAhlberg, Per
By organisation
Evolution and Developmental Biology
Evolutionary Biology

Search outside of DiVA

GoogleGoogle Scholar

urn-nbn

Altmetric score

urn-nbn
Total: 836 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf