Field of Science

A New Paper That is Sure to Stir Up Some Debate

I'm not an expert on feathers so I can't offer an opinion but I'm sure lots of others will.

Dzik, J., Sulej, T., and G. Niedwiedzki. 2010. Possible link connecting reptilian scales with avian feathers from the early Late Jurassic of Kazakstan. Historical Biology 22: 394-402.

Abstract - Organic tissue of a recently found second specimen of feather-like Praeornis from the Karabastau Formation of the Great Karatau Range in southern Kazakstan, has a stable carbon isotope composition indicative of its animal affinity. Three-dimensional preservation of its robust carbonised shaft indicates original high contents of sclerotic organic matter, which makes the originally proposed interpretation of Praeornis as a keratinous integumental structure likely. The new specimen is similar to the holotype of Praeornis in the presence of three 'vanes' on a massive shaft not decreasing in width up to near its tip. Unlike it, the vanes are not subdivided into barbs and the pennate structure is expressed only in the distribution of organic-matter-rich rays. Similar continuous blades border the 'barbs' in the holotype, but the organic matter was removed from them by weathering. It is proposed that the three-vaned structure is a remnant of the ancestral location of scales along the dorsum and their original function in sexual display, similar to that proposed for the Late Triassic probable megalancosaurid Longisquama. Perhaps subsequent rotation around the shaft, in the course of evolution from an ancestral status similar to Praeornis towards the present aerodynamic and protective function of feathers, resulted in the tubular appearance of their buds.

1 comment:

  1. Unless I'm much mistaken, Praeornis was mostly considered as a plant remain - also by Alan Feduccia - and the idea that this new find may belong to Praeornis as well is possibly not so wrong after all ... (in that both represent coaly plant remains). The isotope signal appeared not too convincing to me (especially given the sample size and the use of fish scales as a reference). Was anyone able to discern the three "vanes" in the fossil?

    BTW: Longisquama is neither safely Upper Triassic, nor is its relation with megalancosaurs well established.


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