Rollers,
Coracii, are large-headed, large-beaked insectivorous Birds related
to Kingfishers, Bee-eaters, Hoopoes and Hornbills. They are
restricted to the Old World today, with a but two species found the
tropics or subtropics, but appear to have been more widely
distributed in the past. Like many living Bird-groups, they appear to
have arisen shortly after the End Cretaceous extinction (before which
Avian faunas were dominated by the extinct Toothed Birds), though
precisely where and when is unclear due to a lack of good
Bird-producing sites from the Palaeocene. Fossil Rollers have been
described from the Early Eocene Messel Shale and Green River
Formation of Wyoming, as well as the Late Eocene Quercy deposits of
France, and fragmentary remains not described to species level from
the Early Eocene of Condé-en-Brie, also in France.
In a
paper published in the journal Scientific Reports on 27 September
2016, Estelle Bourdon of The Natural History Museum of Denmark and
Section of Biosystematics at the University of Copenhagen, Anette
Kristoffersen of the Department of Geosciences and Natural ResourceManagement at the University of Copenhagen and Niels Bonde, also of
The Natural History Museum of Denmark and Section of Biosystematics
at the University of Copenhagen, as well as the Fur Museum (MuserumSalling), describe a new species of Roller from the Early Eocene Fur
Formation of Klovbakker Quarry on the Island of Mors, off
northwestern Jutland.
The Fur Formation is a marine diatomite, i.e. a sedimentary rock
formed from the tests (shells) of planktonic Diatoms; such diatomites
can form in both marine and lake deposits, but only far enough from
the shore that the Diatom tests are able to build up without
significant input of sediments from terrestrial environments. These
deposits are noted for the production of numerous Insects and
Vertebrates, the later including Fish, Turtles and Birds. Importantly
the Fur Formation also included numerous layers of volcanic ash,
allowing very precise radiometric dating of the deposits.
The
new Bird is named Septencoracias
morsensis, where
'Septencoracias'
means 'Northern Roller' and 'morsensis'
means 'from Mors'. It is described from a single, largely-intact,
three-dimensionally preserved specimen, which also has preserved
stomach contents. The living Bird would have been about 25 cm in
length, towards the minimum end of the size range seen in living
Rollers.
Septencoracias
morsensis. (a) Photograph of whole specimen. (b) 3D white light
scanning of the whole specimen. (c) Interpretative drawing with
damaged areas of the skull, fish remains and soft tissues represented
in dark grey. Abbreviations: al1–2, phalanges of alular digit; ap,
narial opening; at, atlas; ax, axis; c, cervical vertebrae; ca,
carpometacarpus; cd1–7, caudal vertebrae; co, vertebral costae; cp,
costal process; cr, cranium; d, damage in the skull area; dm, phalanx
of minor digit; dM1, proximal phalanx of major digit; dM2, distal
phalanx of major digit; ec, ectethmoid; f, femur; fi, fish remains;
ft, foramina intertransversaria; fv, fish vertebra; h, humerus; if,
ilioischiadic foramen; is, ischium; md, mandibula; me, mesethmoid;
mx, maxilla; mI, metatarsal I; pa, palatine; pb, pubis; po,
postacetabular wing of ilium; pr, preacetabular wing of ilium; pt,
pterygoid; pu, uncinate process; py, pygostyle; ra, radius; rd,
radial carpal bone; sc, scapula; st, soft tissues; sy, synsacrum; ta,
tarsometatarsus; tb, tibiotarsus; u, ulna; ul, ulnar carpal bone;
I1–2, phalanges of pedal digit I; II1–3, phalanges of pedal digit
II; III1–4, phalanges of pedal digit III; IV1–5, phalanges of
pedal digit IV. The ‘r’ and ‘l’ prefixes indicate right and
left, respectively. Estelle Bourdon in Bourdon et al.
(2016).
The
specimen was found directly above an ash layer dated to 54.04 million
years ago, making it about 54 million years old. This makes it the
oldest known Roller, and places it directly after the Early Eocene
Thermal Maximum, a time when tropical climates could be found as far
north as Denmark. Since other fossil Rollers found in northerly
locations in Europe and America also come from warm Eocene deposits,
it is likely that the preference for hot climates seen in modern
Rollers arose early in the history of the group.
Septencoracias
morsensis. (a) Skull in left lateral view. (b) Right foot in
medial view. (c) Left foot in dorsal view. (d) Right humerus in
cranial view. (e) Right carpometacarpus in ventral view. Bourdon et
al. (2016).
The
stomach contents of Septencoracias
morsensis
comprise the skeletons of at least two Argentinoid Fish. These Fish
reached about 10 cm in size, and are very abundant in the Mors
Formation, apparently having been a food source for many of the other
animals found there. The consumption of Fish is outside the behaviour
of modern Rollers, and may suggest some unrollerlike habits for
Septencoracias
morsensis.
However this does not necessarily mean the Bird was capable of
hunting Fish like a Kingfisher; most Birds will scavenge
opportunistically when the opertunity arises, and the consumption of
Fish may have been an example of such behaviour in a Roller with more
conventional habits.
Life
reconstruction of Septencoracias morsensis.
Salient diagnostic features of the new fossil relative to other
rollers include the larger skull and the small, ovoid and dorsally
positioned narial openings. Septencoracias
is represented with a brownish and bluish plumage, because brownish
and/or bluish feathers occur in all species of Rollers and most
species of Ground-rollers, and are probably primitive within the
Coracii. Estelle Bourdon in Bourdon et al.
(2016).
See also...
Phorusrhacid ‘Terror Birds’ from the Middle Eocene of Western Europe. The Phorusrhacid ‘Terror Birds’ were large, carnivorous flightless Birds
that appear to have held the role of top terrestrial predators in South
America throughout much of the Cenozoic. They are known to have
colonized parts of North America, during...
A flower-visiting Bird from the Middle Eocene Messel Shale of Germany. Several groups of modern Birds are known to feed by visiting flowers to
collect nectar, and in the process serve as pollinators for the plants.
Most notable are...
Fossil Romainvilliine Geese from the Late Eocene of Xinjiang Province, China. The Romainvilliines are an extinct group of large Waterfowl known from
Late Eocene and Early Oligocene of France, Belgium and England. They...
Follow Sciency Thoughts on Facebook.
