''Lutavis'' (meaning "clay bird") is an extinct genus of potentially afroavian bird from the Early Eocene London Clay Formation of

Essex Essex () is a county in the East of England. One of the home counties, it borders Suffolk and Cambridgeshire to the north, the North Sea to the east, Hertfordshire to the west, Kent across the estuary of the River Thames to the south, and Grea ...

, United Kingdom. The genus contains a single species, ''L. platypelvis'', known from a partial skeleton.

Discovery and naming

The

holotype A holotype is a single physical example (or illustration) of an organism, known to have been used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of sever ...

specimen, NMS.Z.2021.40.37, was discovered in 1995 by Michael Daniels in layers of the London Clay Formation (Walton Member), dated to the early

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

, which is located near

Walton-on-the-Naze Walton-on-the-Naze is a seaside town on the North Sea coast and (as Walton le Soken) a former civil parish, now in the parish of Frinton and Walton, in the Tendring district in Essex, England. It is north of Clacton and south of the port of H ...

in Essex, England. This specimen consists of some

thoracic vertebrae In vertebrates, thoracic vertebrae compose the middle segment of the vertebral column, between the cervical vertebrae and the lumbar vertebrae. In humans, there are twelve thoracic vertebrae and they are intermediate in size between the cervical ...

, the

pygostyle Pygostyle describes a skeletal condition in which the final few caudal vertebrae are fused into a single ossification, supporting the tail feathers and musculature. In modern birds, the rectrices attach to these. The pygostyle is the main compone ...

, the majority of the

pectoral girdle The shoulder girdle or pectoral girdle is the set of bones in the appendicular skeleton which connects to the arm on each side. In humans it consists of the clavicle and scapula; in those species with three bones in the shoulder, it consists of ...

, a partial right humerus, partial

ulna The ulna (''pl''. ulnae or ulnas) is a long bone found in the forearm that stretches from the elbow to the smallest finger, and when in anatomical position, is found on the medial side of the forearm. That is, the ulna is on the same side of t ...

e, partial carpometacarpi, carpal bones, wing phalanges, a partial pelvis, a right tarsometatarsus, and several pedal phalanges. In 2022, German paleontologist

Gerald Mayr Gerald Mayr is a German palaeontologist who is Curator of Ornithology at the Senckenberg Research Institute in Frankfurt am Main, Hesse. He has published extensively on fossil birds, especially the Paleogene avifauna of Europe. He is an expert on ...

and British zoologist Andrew C. Kitchener described ''Lutavis platypelvis'', a new genus and species of bird, based on these fossil remains. The generic name, "''Lutavis''", combines the

Latin Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through the power of the ...

words "lutum", meaning "mud" or "clay", in reference to the discovery of the fossil in the London Clay Formation, and "avis", meaning "bird". The specific name, "''platypelvis''", combines the

Greek Greek may refer to: Greece Anything of, from, or related to Greece, a country in Southern Europe: *Greeks, an ethnic group. *Greek language, a branch of the Indo-European language family. **Proto-Greek language, the assumed last common ancestor ...

word "πλᾰτῠ́ς” (”platús”), meaning ”wide”, with “ pelvis”, in reference to the taxon's wide, shallow pelvis.

Description

Although the tarsometatarsus of ''Lutavis'' shares some similarities with those of the extinct '' Plesiocathartes'' and ''

Paracrax ''Paracrax'' ("near curassow") is a genus of extinct North American flightless birds, possibly related to modern seriemas and the extinct terror birds. Part of Bathornithidae (though some analysis recover it as closer to the living seriemas in ...

'', the remainder of the skeleton is significantly different, with very few similarities. Preserved fossilized toe pad

integument In biology, an integument is the tissue surrounding an organism's body or an organ within, such as skin, a husk, shell, germ or rind. Etymology The term is derived from ''integumentum'', which is Latin for "a covering". In a transferred, or ...

was observed on a piece of

matrix Matrix most commonly refers to: * ''The Matrix'' (franchise), an American media franchise ** ''The Matrix'', a 1999 science-fiction action film ** "The Matrix", a fictional setting, a virtual reality environment, within ''The Matrix'' (franchis ...

collected with a pedal phalanx. A similar instance was seen in the holotype of the contemporary '' Ypresiglaux michaeldanielsi''. ''Lutavis'' had relatively short legs compared to other birds. Although the tuberculum dorsale of the humerus is small (while it is large in extant birds capable of sudden take-offs), the coracoid is especially large, suggesting that ''Lutavis'' was capable of well-developed flight.

Classification

Mayr and Kitchener (2022) could not confidently place ''Lutavis'' within any avian clade due to the lack of derived features in the holotype. They suggested that an assignment to the Leptosomiformes would be possible but highly speculative, and that future work should be done to establish a more confident placement.

References

{{Taxonbar, from=Q115937090 Eocene birds of Europe Extinct birds of Europe Prehistoric bird genera Fossil taxa described in 2022 Birds described in 2022

Discovery and naming

Description

Classification

See also

References