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The pectoral fin of Panderichthys and the origin of digits.
Nature 2008; 456(7222):636-8Nat

Abstract

One of the identifying characteristics of tetrapods (limbed vertebrates) is the presence of fingers and toes. Whereas the proximal part of the tetrapod limb skeleton can easily be homologized with the paired fin skeletons of sarcopterygian (lobe-finned) fish, there has been much debate about the origin of digits. Early hypotheses interpreted digits as derivatives of fin radials, but during the 1990s the idea gained acceptance that digits are evolutionary novelties without direct equivalents in fish fin skeletons. This was partly based on developmental genetic data, but also substantially on the pectoral fin skeleton of the elpistostegid (transitional fish/tetrapod) Panderichthys, which appeared to lack distal digit-like radials. Here we present a CT scan study of an undisturbed pectoral fin of Panderichthys demonstrating that the plate-like 'ulnare' of previous reconstructions is an artefact and that distal radials are in fact present. This distal portion is more tetrapod-like than that found in Tiktaalik and, in combination with new data about fin development in basal actinopterygians, sharks and lungfish, makes a strong case for fingers not being a novelty of tetrapods but derived from pre-existing distal radials present in all sarcopterygian fish.

Authors+Show Affiliations

Subdepartment of Evolutionary Organismal Biology, Department of Physiology and Developmental Biology, Evolutionary Biology Centre, Uppsala University, Norbyvägen 18A, 752 36 Uppsala, Sweden. catherine.boisvert@ebc.uu.seNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

18806778

Citation

Boisvert, Catherine A., et al. "The Pectoral Fin of Panderichthys and the Origin of Digits." Nature, vol. 456, no. 7222, 2008, pp. 636-8.
Boisvert CA, Mark-Kurik E, Ahlberg PE. The pectoral fin of Panderichthys and the origin of digits. Nature. 2008;456(7222):636-8.
Boisvert, C. A., Mark-Kurik, E., & Ahlberg, P. E. (2008). The pectoral fin of Panderichthys and the origin of digits. Nature, 456(7222), pp. 636-8. doi:10.1038/nature07339.
Boisvert CA, Mark-Kurik E, Ahlberg PE. The Pectoral Fin of Panderichthys and the Origin of Digits. Nature. 2008 Dec 4;456(7222):636-8. PubMed PMID: 18806778.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - The pectoral fin of Panderichthys and the origin of digits. AU - Boisvert,Catherine A, AU - Mark-Kurik,Elga, AU - Ahlberg,Per E, Y1 - 2008/09/21/ PY - 2008/06/12/received PY - 2008/08/14/accepted PY - 2008/9/23/pubmed PY - 2009/1/7/medline PY - 2008/9/23/entrez SP - 636 EP - 8 JF - Nature JO - Nature VL - 456 IS - 7222 N2 - One of the identifying characteristics of tetrapods (limbed vertebrates) is the presence of fingers and toes. Whereas the proximal part of the tetrapod limb skeleton can easily be homologized with the paired fin skeletons of sarcopterygian (lobe-finned) fish, there has been much debate about the origin of digits. Early hypotheses interpreted digits as derivatives of fin radials, but during the 1990s the idea gained acceptance that digits are evolutionary novelties without direct equivalents in fish fin skeletons. This was partly based on developmental genetic data, but also substantially on the pectoral fin skeleton of the elpistostegid (transitional fish/tetrapod) Panderichthys, which appeared to lack distal digit-like radials. Here we present a CT scan study of an undisturbed pectoral fin of Panderichthys demonstrating that the plate-like 'ulnare' of previous reconstructions is an artefact and that distal radials are in fact present. This distal portion is more tetrapod-like than that found in Tiktaalik and, in combination with new data about fin development in basal actinopterygians, sharks and lungfish, makes a strong case for fingers not being a novelty of tetrapods but derived from pre-existing distal radials present in all sarcopterygian fish. SN - 1476-4687 UR - https://www.unboundmedicine.com/medline/citation/18806778/The_pectoral_fin_of_Panderichthys_and_the_origin_of_digits_ L2 - https://doi.org/10.1038/nature07339 DB - PRIME DP - Unbound Medicine ER -