Evidence corroborates identity of isolated fossil feather as a wing covert of Archaeopteryx

The historic fossil feather from the Jurassic Solnhofen has played a pivotal but controversial role in our evolutionary understanding of dinosaurs and birds. Recently, a study confirmed the diagnostic morphology of the feather’s original calamus, but nonetheless challenged the proposed identity as an Archaeopteryx covert. However, there are errors in the results and interpretations presented. Here we show that the feather is most likely an upper major primary covert, based on its long calamus (23.3% total length) and eight other anatomical attributes. Critically, this hypothesis is independently supported by evidence of similar primary coverts in multiple specimens of Archaeopteryx–including from the same fossil site and horizon as the isolated feather. We also provide additional insights, such as an updated colour reconstruction of the entire feather as matte black, with 90% probability. Given the isolated nature of the fossil feather, we can never know the anatomical and taxonomic provenance with 100% certainty. However, based on all available evidence, the most empirical and parsimonious conclusion is that this feather represents a primary covert from the ancient wing of Archaeopteryx.

Using δ2H stable isotope analysis to identify the origin of a first winter Red-breasted Goose Branta ruficollis caught in Norway

We analysed the stable isotope of hydrogen (δ2H) in first generation median wing covert feathers sampled from a free-flying first winter Red-breasted Goose Branta ruficollis caught in Storøya, Norway in late April 2019. The highly depleted δ2H values corresponded to those predicted if the bird had grown feather in the Russian Arctic breeding areas of this species and were much more highly depleted compared to predicted values of a bird raised in captivity in Norway or elsewhere in western Europe. Although these data do not provide irrefutable proof of the individual’s wild origin, these results strongly suggest that even records outside the normal range for this species can potentially constitute a genuinely wild-reared individual.

Calamicoptes anatidus sp. nov., a new quill wall mite (Acari: Laminosioptidae) from the Greater Scaup Aythya marila (L.) (Aves: Anseriformes)

Calamicoptes anatidus sp. nov., a new species of rarely found parasitic mites of the family Laminosioptidae (Acari: Astigmata) is described from quill walls of wing covert feathers of Aythya marila Linnaeus (Anseriformes: Anatidae) captured in Poland. This is the first record of the family Laminosioptidae on birds of the order Anseriformes and the first record of this mite family in the fauna of Poland. Females of the new species are most similar to those of C. arenariae Lombert, Gaud et Lukoschus, 1984 and differ from them by the presence of the pygidial shield, which covers dorsal and ventro-lateral parts of the opisthosoma, and by having setae c2 and d2 short and subequal in length, and setae se and cp not reaching the metapodonotal shield.