''Septencoracias'' is an extinct genus of

bird Birds are a group of warm-blooded vertebrates constituting the class (biology), class Aves (), characterised by feathers, toothless beaked jaws, the Oviparity, laying of Eggshell, hard-shelled eggs, a high Metabolism, metabolic rate, a fou ...

related to modern rollers and other

Coraciiformes The Coraciiformes are a group of usually colourful birds including the kingfishers, the bee-eaters, the rollers, the motmots, and the todies. They generally have syndactyly, with three forward-pointing toes (and toes 3 & 4 fused at their b ...

such as

kingfisher Kingfishers are a family, the Alcedinidae, of small to medium-sized, brightly coloured birds in the order Coraciiformes. They have a cosmopolitan distribution, with most species living in the tropical regions of Africa, Asia, and Oceania, ...

bee-eater The bee-eaters are a group of birds in the family (biology), family Meropidae, containing three genera and thirty-one species. Most species are found in Africa and Asia, with a few in southern Europe, Australia, and New Guinea. They are characte ...

s, motmots, and todies. It contains two species, ''Septencoracias morsensis'' described in 2016, and ''S. simillimus'', which was named in 2024. It was found in the

Fur Formation The Fur Formation is a marine geological formation of Ypresian ( Lower Eocene Epoch, c. 56.0-54.5 Ma) age which crops out in the Limfjord region of northern Denmark from Silstrup via Mors and Fur to Ertebølle, and can be seen in many cliffs and ...

Denmark Denmark is a Nordic countries, Nordic country in Northern Europe. It is the metropole and most populous constituent of the Kingdom of Denmark,, . also known as the Danish Realm, a constitutionally unitary state that includes the Autonomous a ...

, dating back to the

Ypresian In the geologic timescale the Ypresian is the oldest age (geology), age or lowest stage (stratigraphy), stratigraphic stage of the Eocene. It spans the time between , is preceded by the Thanetian Age (part of the Paleocene) and is followed by th ...

of the Lower Eocene Epoch, about 54 million years ago. ''Septencoracias'' is one of the earliest known members of Coraciiformes, lending insight into the earliest radiation of this group.

Description

''Septencoracias'' was a small bird the size of a Northern carmine bee-eater, ''Merops nubicus'', about 25 cm in length. It had a large skull in comparison to its body, about twice the length of the humerus. It is much larger than modern day rollers and its sister taxon '' Primobucco'', more similar in size and proportion to kingfishers, motmots, and bee-eaters. It had a stout, slightly curved beak, and the upper ridge of the beak curves gradually towards the tip of the bill like in living roller species. This is different from ''Primobucco'' which has stronger curvature on the anterior end of the beak. It had small, egg-shaped nasal openings, much different than any of its close extinct relatives or extant rollers, which have either elongated openings, slit-like openings, or large triangular nares. The only fossil specimen of ''Septencoracias'' does not preserve the sternum and shoulder girdle, except for the left scapula, which is not bifurcated as in Late Eocene and later rollers. Like in ''Primobucco'', ''Septencoracias'' has a small claw on its alular digit, which is usually absent in modern birds. ''Septencoracias'' had a very wide pelvis, and had similar proportions in its hind limbs as modern rollers. Though most modern Coraciiformes show

syndactyly Syndactyly is a condition wherein two or more digits are fused together. It occurs normally in some mammals, but is an unusual condition in humans. The term is . Classification Syndactyly can be simple or complex. * In simple syndactyly, adja ...

, with three forward-pointing toes and toes three and four fused at the base, ''Septencoracias'' is not entirely certain to have this condition. The third and fourth digit do lie on top of each other in the fossil, with the second digit separated; however in the left foot the fourth digit is slightly separated from the third, and thus it cannot be said for certain if this condition is present in ''Septencoracias''. The fossil remains show soft tissue preservation, mostly in the thoracic and abdominal cavities, though portions were also seen in the skull. Apart from remains of potential food material, these remains have not been thoroughly examined.

Discovery and naming

''Septencoracias'' is based on a single specimen, MGUH.VP 9509, consisting of most of the skeleton but lacking the sternum and portions of the shoulder girdle. The specimen was preserved in three dimensions, with the skull partly eroded due to it being exposed at the time of discovery. It was discovered in the Moclay Pit on the Island of Mors, in

Jutland Jutland (; , ''Jyske Halvø'' or ''Cimbriske Halvø''; , ''Kimbrische Halbinsel'' or ''Jütische Halbinsel'') is a peninsula of Northern Europe that forms the continental portion of Denmark and part of northern Germany (Schleswig-Holstein). It ...

, Denmark, in the Fur Formation. This location dates to the Ypresian age of the Early Eocene, around 54 million years ago. It was found during a geology field course in an abandoned diatomite quarry. The genus name stems from 'septentrio', meaning north, and the genus name of many modern rollers, '' Coracias''. The specific name stems from the Island of Mors. An additional specimen from the Tielt Formation in Egem,

Belgium Belgium, officially the Kingdom of Belgium, is a country in Northwestern Europe. Situated in a coastal lowland region known as the Low Countries, it is bordered by the Netherlands to the north, Germany to the east, Luxembourg to the southeas ...

was referred to cf. ''Septencoracias'' sp. in 2019. The specimen only consists of an isolated tarsometatarsus, however it resembles that of ''Septencoracias'' in both size and shape more than any other fossil Coraciiformes, although it is slightly larger.

Classification

A phylogenetic analysis in 2016 recovered ''Septencoracias'' as the sister taxon of '' Primobucco''. The most parsimonious tree, based on 21 taxa, is shown below.

Paleobiology

''Septencoracias'' is the oldest known member of the

, so it shows that this group was already fairly diversified by the Early Eocene, following the end-Cretaceous extinction. It already shows many of the derived characteristics of this group, as well as characteristics shared by its sister taxon, ''Primobucco''. It was found with fish remains in its gut, of a very common taxon from the Fur Formation, argentinoids of about 10 cm in length. These may be the contents of the stomach, indicating that ''Septencoracias'' fed upon these fish prior to its death, and they were dissociated due to digestion and may have spread outside of the abdomen due to decay and breakage. This contributes to the idea that early roller and roller relatives had a much more varied diet than modern members of the group, which almost exclusively feed upon insects and small land vertebrates. However, ''Septencoracias'' probably mostly fed on insects and small land vertebrates, similar to its modern relatives, given that it was a terrestrial bird. ''Septencoracias'' was found in the Eastern Hemisphere, which is where all modern rollers are found, though they all occur in modern tropical and subtropical regions. Given the warmer climate of the Eocene, the finding of ''Septencoracias'' in Denmark indicates that the range of early Coraciiformes was much wider within the Northern Hemisphere during this time, due to the increased number of suitable habitats. As the globe cooled, the range of rollers was thus reduced to their present ranges. This was part of a much broader trend in which many modern bird clades that were formerly found in higher latitudes during the Eocene are now restricted to the tropics and subtropics from cooling climates.

References

{{Taxonbar, from=Q28432503 Coraciiformes Eocene birds Paleogene birds of Europe Fossils of Denmark Fossil taxa described in 2016 Prehistoric bird genera Fur Formation