New Crassigyrinus-like fibula from the Tournaisian (earliest Carboniferous) of Nova Scotia

October 13, 2020

Kendra I. Lennie (1,2), Chris F. Mansky (3), Jason S. Anderson (2,4)
Canadian Journal of Earth Sciences, 57, Issue 11, October 2020: 1365-1369. DOI: 10.1139/cjes-2019-0128


fin-to-limb, Carboniferous, Crassigyrinidae, early tetrapod, vertebrate evolution, Romer’s Gap


The transition between the Devonian and Carboniferous is important for tetrapod vertebrates. By the end of the Devonian the first limbs are present in aquatic animals, and by the mid Carboniferous fully terrestrial tetrapods have diversified. Knowledge of the fin-to-limb transition is sparse because few fossils from the earliest Carboniferous (Tournaisian) are known. Blue Beach Nova Scotia, in addition to a small number of sites in Scotland and Australia, is an exception to this global trend. Previous reports from Blue Beach identified fossils from a variety of Devonian-like and Carboniferous-like tetrapod body forms, making it a valuable site for studying the fin-to-limb transition. Here we report on a new left fibula from Blue Beach, which we attribute to the later occurring Visean-aged (early Carboniferous) Crassigyrinidae. Recent investigations of deposits in Scotland, similar in age to the Tournaisian exposed at Blue Beach, have found Crassigyrinus-like elements as well, reinforcing this 20-million-year lineage extension.

Author Affiliation

(1) Biological Sciences, University of Calgary, 507 Campus Drive NW, Calgary, AB T2N 1N4, Canada.
(2) McCaig Bone and Joint Institute, University of Calgary, Calgary, AB T2N 4Z6, Canada.
(3) Blue Beach Fossil Museum, 127 Blue Beach Road, Hantsport, NS B0P 1P0, Canada.
(4) Comparative Biology and Experimental Medicine, University of Calgary, 3330 Hospital Dr. NW, Calgary, AB T2N 4N1, Canada.