Styloichthys as the oldest coelacanth: Implications for early osteichthyan interrelationships

Journal article

The Early Devonian (Lochkovian) sarcopterygian fish Styloichthys has been interpreted as the immediate sister taxon of the clade comprising both the dipnoan and the tetrapod total groups, but support for this placement is weak. Many derived characters of the lower jaw, braincase and dermal skull align Styloichthys with coelacanths and their bearing on the affinities of this genus is set against the evidence in support of earlier interpretations. A revised cladistic analysis places Styloichthys as the most basal coelacanth, which, if correct, fills conspicuous stratigraphic and morphological gaps in the fossil record of this clade. This analysis also raises questions about the phylogenetic placement of onychodonts and the Early Devonian 'actinopterygians' Ligulalepis and Dialipina, indicating that these taxa should be the specific targets of future systematic study. © The Natural History Museum.

Authors: Friedman, M

• Publication status: Published
• Journal: JOURNAL OF SYSTEMATIC PALAEONTOLOGY
• Volume: 5
• Issue: 3
• Pages: 289-343
• Publication date: 2007-09-01
• DOI: 10.1017/S1477201907002052
• EISSN: 1478-0941
• ISSN: 1477-2019
• Language: English
• Keywords: Sarcopterygii; actinistia; Lochkovian; Xitun formation; phylogeny; Devonian