and that feathered coelurosaur tail preserved in Burmese amber which was described by Xing et al. (2016) might be avian. A study on the anatomy of the braincase of birds and non-avian dinosaurs, evaluating whether there is a link between changes in brain anatomy and loss of flight, is published by Gold & Watanabe (2018). A study on the preservation potential of feather keratin in the fossil record is published by Schweitzer et al. (2018); the study is subsequently criticized by Saitta & Vinther (2019). Description of 31 samples of Cretaceous amber from Myanmar that contain feathers, providing new information on the morphology and variability of rachis-dominated feathers of Cretaceous birds, is published by Xing et al. (2018). A pseudoscorpion attached to barbules of a contour feather, possibly documenting a phoretic association between pseudoscorpions and Mesozoic birds, is described from the Cretaceous amber from Myanmar by Xing, McKellar & Gao (2018). A redescription of the bird trackway originally labeled Aquatilavipes anhuiensis from the Lower Cretaceous Qiuzhuang Formation (Anhui, China) is published by Xing et al. (2018), who transfer this ichnospecies to the ichnogenus Koreanaornis. Early Cretaceous (Aptian) bird footprints are described from the Kitadani Formation (Japan) by Imai, Tsukiji & Azuma (2018). New avian ichnospecies Ignotornis canadensis is described from the Lower Cretaceous (Albian) Gates Formation (Canada) by Buckley, McCrea & Xing (2018). Ignotornid tracks are described from the Lower Cretaceous of Jiangsu (China) by Xing et al. (2018), representing the first known record of the ichnogenus Goseongornipes from China. The twelfth specimen of Archaeopteryx, the oldest reported so far, is described by Rauhut, Foth & Tischlinger (2018). This was named as the new genus Alcmonavis in 2019. A study on the geometric properties of the wing bones of Archaeopteryx is published by Voeten et al. (2018), who interpret their findings as indicating that Archaeopteryx was able to actively use its wings to take to the air (using a different flight stroke than used by extant birds). Gastrolith masses preserved in five specimens of Jeholornis will be described by O'Connor et al. (2018). A new confuciusornithid specimen, most similar to Eoconfuciusornis zhengi but also sharing traits with Confuciusornis, will be described from the Upper Cretaceous Huajiying Formation (China) by Navalón et al. (2018). A study on the morphology of the skull of Confuciusornis sanctus is published by Elżanowski, Peters & Mayr (2018). An exceptionally-preserved specimen of Confuciusornis, preserving elaborate plumage