Waltonavis

Waltonavis; Temporal range: early Eocene, ; 54.6–55 Ma PreꞒ Ꞓ O S D C P T J K Pg N ↓
	Fossil material of Waltonavis spp.
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	Aves
Clade:	Coraciimorphae
Clade:	Cavitaves
Order:	Leptosomiformes (?)
Genus:	† Waltonavis ; Mayr & Kitchener, 2022
Type species
	†Waltonavis paraleptosomus; Mayr & Kitchener, 2022
Other species
	†W. danielsiMayr & Kitchener, 2022;

Last updated May 13, 2024

Waltonavis (meaning "Walton bird") is an extinct genus of potentially leptosomiform bird from the Early Eocene London Clay Formation of Essex, United Kingdom. The genus contains two species: W. paraleptosomus and W. danielsi, both known from partial skeletons.^[1]

Discovery and naming

Waltonavis was described in 2022 by German paleontologist Gerald Mayr and British zoologist Andrew C. Kitchener. The generic name, "Waltonavis", combines a reference to the type locality with the Latin word "avis", meaning "bird". The type species, W. paraleptosomus, was described on the basis of a partial skeleton collected in 1988. This specimen, NMS.Z.2021.40.16, which includes the left quadrate and pterygoid, a partial left scapula, a left coracoid, the cranial portion of the sternum, and a left and partial right tarsometatarsus, was designated as the holotype. NMS.Z.2021.40.17—19, additional specimens collected in 1996, 1983, and 1988, respectively, include more fossil material, including the remains of a juvenile individual. They were also referred to W. paraleptosomus. These fossils were discovered by Michael Daniels in layers of the London Clay Formation (Walton Member), dated to the early Ypresian, which is located near Walton-on-the-Naze in Essex, England. The specific name, "paraleptosomus", is derived from the Greek “παρα” (“para”) and the name of the extant bird Leptosomus , in reference to similarities between the bones of the two taxa.^[1]

Additional fossil material collected in 1985 was assigned to a separate species of Waltonavis, W. danielsi. The holotype of W. danielsi, NMS.Z.2021.40.20, consists of several vertebrae, the right coracoid, a partial right scapula, a right humerus, a partial left humerus, a right ulna, a partial left ulna, a left carpometacarpus, partial phalanges, a partial right femur, a partial right tibiotarsus, and a partial left tarsometatarsus. The specific name, “danielsi” honors Michael Daniels, the discoverer of the holotype.^[1]

Several additional fragmentary skeletons collected in the late 1900s by Daniels were assigned to Waltonavis, but they lack sufficient material to be assigned to either W. paraleptosomus or W. danielsi.^[1]

Description

An extant Leptosomus discolor (cuckoo-roller), a relative of Waltonavis Leptosomusdiscolorcrop.jpg — An extant *Leptosomus discolor* (cuckoo-roller), a relative of *Waltonavis*

Waltonavis was similar in size and morphology to Lapillavis , an extinct bird from the mid-Eocene Messel pit of Germany. It also shows several similarities to the larger extant Leptosomus , which feeds on large insects and small reptiles. Due to differences in beak and wing bone shape, Waltonavis likely had feeding habits distinct from Leptosomus.^[1]

Classification

Mayr and Kitchener (2022) noted several similarities between Waltonavis and leptosomiforms. They suggested that an assignment to the Leptosomiformes is likely, but that a unique combination of features makes precise classification difficult. The cladogram below displays the relation of Waltonavis within Telluraves.^[1]

Related Research Articles

Copepteryx is an extinct genus of flightless bird of the family Plotopteridae, endemic to Japan during the Oligocene living from 28.4 to 23 mya, meaning it existed for approximately 5.4 million years.

<i>Palaeoglaux</i> Extinct genus of birds

Palaeoglaux is a genus of fossil owls from the Eocene epoch. The two known species are P. perrierensis from the Upper Eocene of Quercy, France, and P. artophoron from the Middle Eocene Messel shales, Germany. The holotype of P. perrierensis is a partial left coracoid in the Collection Université Montpellier, accession number PRR 2585. The four paratypes are the distal part of a left humerus (PRR2591), the proximal part of a left ulna, the distal part of a left ulna, and the distal part of a right tarsometatarsus. The type specimen of P. artophoron is a fossil slab and counterslab containing most of the postcranial skeleton and some feather impressions. This specimen is in the collection of the Forschunginstitut Senckenberg, accession number SMF-ME 1144 A and B.

Eurofluvioviridavis is a genus of extinct primitive birds from the Middle Eocene Messel Pit, Germany. It contains a single species, Eurofluvioviridavis robustipes. It is related to Avolatavis and Vastanavis, other members of the family Vastanavidae.

Hokkaidornis is an extinct genus of penguin-like plotopterid from the Late Oligocene of Hokkaido, Japan.

Kupoupou is an extinct genus of bird from the Paleocene-aged Takatika Grit of the Chatham Islands, New Zealand which is believed to be the oldest penguin genus known to date. The type species, K. stilwelli, was named and described by Blokland et al. in 2019.

Danielsraptor is an extinct genus of masillaraptorid bird from the Early Eocene (Ypresian) Walton Member of the London Clay Formation in Essex, United Kingdom. The genus contains a single species, D. phorusrhacoides, known from a partial skeleton.

Nasidytes is an extinct genus of loon (Gaviiformes) that lived during the early Eocene in what is now Great Britain. It contains a single species, N. ypresianus. Nasidytes is the earliest unambiguously identified loon in the fossil record.

Tonsala is an extinct genus of Plotopteridae, a family of flightless seabird similar in biology with penguins, but more closely related to modern cormorants. The genus is known from terrains dated from the Late Oligocene of the State of Washington and Japan.

Pliolymbus is a fossil genus of grebe known from the Late Pliocene to Early Pleistocene of United States and Mexico. It is known from a single species, P. baryosteus.

Ypresiglaux is an extinct genus of strigiform bird from the Early Eocene London Clay Formation of Essex, United Kingdom and Nanjemoy Formation of Virginia, United States. The genus contains two species: Y. michaeldanielsi, known from a partial skeleton, and Y. gulottai, known from a distal tarsometatarsus.

Lutavis is an extinct genus of potentially afroavian bird from the Early Eocene London Clay Formation of Essex, United Kingdom. The genus contains a single species, L. platypelvis, known from a partial skeleton.

Psittacomimus is an extinct genus of psittacopedid bird from the Early Eocene London Clay Formation of Essex, United Kingdom. The genus contains a single species, P. eos, known from a partial skeleton.

Minutornis is an extinct genus of parapasserine bird from the Early Eocene London Clay Formation of Essex, United Kingdom. The genus contains a single species, M. primoscenoides, known from a fragmentary skeleton.

Klallamornis is an extinct genus of Plotopteridae, a family of large, flightless birds related to modern cormorants, darters, gannets, and boobies. This genus included the largest North American plotopterids. Its remains can be found in Late Eocene to Late Oligocene rocks from the Makah Formation, the overlying Pysht Formation and the Lincoln Creek Formation of the State of Washington. During its existence, Klallamornis was the largest plotopterid on the North American continent. The first fossil remains attributed to the taxon were collected in 1983, although the genus wasn't described until 2016.

Charadriisimilis is an extinct genus of charadriiform birds from the Early Eocene (Ypresian) London Clay of Walton-on-the-Naze, United Kingdom. The genus contains a single species, Charadriisimilis essexensis, known from partial postcranial remains.

Pulchrapollia is an extinct genus of halcyornithid bird from the Early Eocene London Clay of Walton-on-the-Naze, United Kingdom and the Nanjemoy Formation of Virginia, United States. The genus contains three species, Pulchrapollia gracilis, Pulchrapollia tenuipes and Pulchrapollia eximia.

Serudaptus is an extinct genus of halcyornithid bird from the Middle Eocene Messel pit in Hesse, Germany. The genus contains one species, Serudaptus pohli, and is known for long, raptorial claws on its zygodactyl feet.

Parapsittacopes is an extinct genus of psittacopedid bird from the Early Eocene London Clay, United Kingdom. The genus contains one species, Parapsittacopes bergdahli.

Eofringillirostrum is an extinct species of bird known from the Early Eocene Green River Formation of the Western United States and from the Messel Pit in Germany. The genus contains two species, Eofringillirostrum boudreauxi and Eofringillirostrum parvulum. They are the earliest known fossil birds to have a finch-like beak.

Sororavis is an extinct genus of bird from the Early Eocene London Clay of Walton-on-the-Naze, United Kingdom. It contains a single named species, Sororavis solitarius. It is a member of the Morsoravidae.

References

1 2 3 4 5 6 Mayr, Gerald; Kitchener, Andrew C. (2022-11-30). "New species from the early Eocene London Clay suggest an undetected early Eocene diversity of the Leptosomiformes, an avian clade that includes a living fossil from Madagascar". Palaeobiodiversity and Palaeoenvironments. 103 (3): 585–608. doi: 10.1007/s12549-022-00560-0 . ISSN 1867-1594. S2CID 254333827.

This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.

[Waltonavis-1] 1 2 3 4 5 6 Mayr, Gerald; Kitchener, Andrew C. (2022-11-30). "New species from the early Eocene London Clay suggest an undetected early Eocene diversity of the Leptosomiformes, an avian clade that includes a living fossil from Madagascar". Palaeobiodiversity and Palaeoenvironments. 103 (3): 585–608. doi: 10.1007/s12549-022-00560-0 . ISSN 1867-1594. S2CID 254333827.

[1]