Non-iridescent structural colour in avian feathers is produced by coherent light scattering through quasi-ordered nanocavities in the keratin cortex of the barbs. To absorb unscattered light, melanosomes form a basal layer underneath the nanocavities. It has been shown that throughout Aves, melanosome morphology reflects broad categories of melanin-based coloration, as well as iridescence, allowing identification of palaeocolours in exceptionally preserved fossils. However, no studies have yet investigated the morphology of melanosomes in non-iridescent structural colour. Here, we analyse a wide sample of melanosomes from feathers that express non-iridescent structural colour from a phylogenetically broad range of extant avians to describe their morphology and compare them with other avian melanosome categories. We find that investigated melanosomes are typically wide (approx. 300 nm) and long (approx. 1400 nm), distinct from melanosomes found in black, brown and iridescent feathers, but overlapping significantly with melanosomes from grey feathers. This may suggest a developmental, and perhaps evolutionary, relationship between grey coloration and non-iridescent structural colours. We show that through analyses of fossil melanosomes, melanosomes indicative of non-iridescent structural colour can be predicted in an Eocene stem group roller ( Eocoracias : Coraciiformes) and with phylogenetic comparative methods the likely hue can be surmised. The overlap between melanosomes from grey and non-iridescent structurally coloured feathers complicates their distinction in fossil samples where keratin does not preserve. However, the abundance of grey coloration relative to non-iridescent structural coloration makes the former a more likely occurrence except in phylogenetically bracketed specimens like the specimen of Eocoracias studied here.

Procolophonids were diverse small reptiles through the late Permian and Triassic. Relatively complete specimens of various taxa are known from the Early and Late Triassic, but the 10 or so Middle Triassic taxa, from South Africa, Russia, China and the UK, are mostly incomplete, being known only from skulls or partial and poorly preserved isolated elements. Because of their small size, it has often been difficult to establish details of anatomy using physical preparation methods, so application of scanning technology can massively improve knowledge. Here, we describe the first substantial portion of a skull and anterior postcranial skeleton of the genus Kapes, known from Russia and the UK. CT scanning and 3D digital restoration of the new specimen from the Anisian Otter Sandstone of Devon, UK, reveal anatomical details previously unknown for this taxon, most notably the enlarged quadratojugal processes. This is also one of the few mature procolophonid specimens with a preserved postcranium, and it gives valuable insight into ossification patterns. Fused sutures of the skull, fused scapulocoracoid, and heavily worn teeth show evidence of the common reptilian ossification pattern with a possible limitation in tooth replacement. There is sufficient anatomical information to include Kapes bentoni for the first time in a cladistic analysis, which shows that it is sister to the Russian Kapes majmesculae and part of a clade of Anisian taxa phylogenetically more basal than Procolophon. Inferences on the function of the quadratojugal spines and fossorial mode of life are also considered.

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Fossil remains of the European Roller Coracias garrulus in Croatia are relatively rare. The European Roller has been found at four sites situated along the Adriatic coast: Marlera I and Šandalja II in the northern Adriatic, and Vela Spila and Markova Spilja on the southern part. The oldest find is from Marlera I, which dates back to the Late Pleistocene (Marine Isotope Stage 3-MIS 3) and the youngest are the Holocene (MIS 1) finds at Vela Spila and Markova Spilja. Immature bones were found in Vela Spila deposits, indicating breeding during the Late Pleistocene in the southern Adriatic. So far, the European Roller has not been determined in deposits from continental Croatia.