Details

Autor(en) / Beteiligte

• Arratia, Gloria

Titel

Identifying patterns of diversity of the actinopterygian fulcra

Ist Teil von

• Acta zoologica (Stockholm), 2009-05, Vol.90 (s1), p.220-235

Ort / Verlag

Oxford, UK: Blackwell Publishing Ltd

Erscheinungsjahr

2009

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• Fin rays, scutes or ridge scales, and fulcra have been traditionally interpreted as modified scales, but their diversity has been almost ignored. Based on results presented here, revised definitions of these elements are provided. At least two patterns of basal fulcra are found in actinopterygians: in Pattern I all or most basal fulcra are paired elements, whereas in Pattern II, a series of unpaired basal fulcra that are bifurcated proximally, and whose forking gradually becomes larger caudad, are followed by a series of paired elements. Basal fulcra are commonly present on unpaired fins of lower actinopterygians, including basal neopterygians. Among living fish they are absent in polypteriforms, Amia and teleosts. Fringing fulcra are always paired. Three patterns of fringing fulcra series are described: the series of fringing fulcra in basal actinopterygians is formed by expanded terminal segments of marginal lepidotrichia (Pattern A). Another series is formed by a combination of slightly expanded or modified terminal segments of rays and independent spiny, small elements (Pattern B). The third series is formed of small, spiny ossified elements positioned along the leading marginal fin ray(s) (Pattern C). Other patterns of basal and fringing fulcra remain to be investigated, along with their phylogenetic implications.