Homology of fin lepidotrichia in osteichthyan fishes

Johanson, Zerina, Burrow, Carole, Warren, Anne and Garvey, Jillian (2005) Homology of fin lepidotrichia in osteichthyan fishes. Lethaia, 38 1: 27-36. doi:10.1080/00241160510013141

Author Johanson, Zerina
Burrow, Carole
Warren, Anne
Garvey, Jillian
Title Homology of fin lepidotrichia in osteichthyan fishes
Journal name Lethaia   Check publisher's open access policy
ISSN 1502-3931
Publication date 2005
Sub-type Article (original research)
DOI 10.1080/00241160510013141
Volume 38
Issue 1
Start page 27
End page 36
Total pages 10
Editor S. Stouge
Place of publication Norway
Publisher Taylor and Francis
Collection year 2005
Language eng
Subject C1
270501 Animal Systematics, Taxonomy and Phylogeny
780105 Biological sciences
Abstract Lepidotrichia are dermal elements located at the distal margin of osteichthyan fins. In sarcopterygians and actinopterygians, the term has been used to denote the most distal bony hemisegments and also the more proximal, scale-covered segments which overlie endochondral bones of the fin. In certain sarcopterygian fishes, including the Rhizodontida, these more proximal, basal segments are very long, extending at least half the length of the fin. The basal segments have a subcircular cross section, rather than the crescentic cross section of the distal lepidotrichial hemisegments, which lack a scale cover and comprise short, generally regular, elements. In rhizodonts and other sarcopterygians, e.g. Eusthenopteron, the basal elements are the first to appear during fin development, followed by the endochondral bones and then the distal lepidotrichia. This sequence contradicts the 'clock-face model' of fin development proposed by Thorogood in which the formation of endochondral bones is followed by development of lepidotrichia. However, if elongate basal 'lepidotrichia' are not homologous with more distal, jointed lepidotrichia and if the latter form within a distal fin-fold and the former outside this fold, then Thorogood's 'clock-face' model remains valid. This interpretation might indicate that the fin-fold has been lost in early digited stem-tetrapods such as Acanthostega and Ichthyostega and elongate basal elements, but not true lepidotrichia, occur in the caudal fins of these taxa.
Keyword Paleontology
Clock Model
Dermal Skeleton
Q-Index Code C1

Document type: Journal Article
Sub-type: Article (original research)
Collection: School of Agriculture and Food Sciences
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Citation counts: TR Web of Science Citation Count  Cited 10 times in Thomson Reuters Web of Science Article | Citations
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Created: Wed, 15 Aug 2007, 05:21:42 EST