Tympanonesiotes

Last updated

Tympanonesiotes
Temporal range: Late Oligocene or Early Miocene (see text)
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Aves
Order: Odontopterygiformes
Family: Pelagornithidae
Genus: Tympanonesiotes
Hopson, 1964
Species:
T. wetmorei
Binomial name
Tympanonesiotes wetmorei
Hopson, 1964
Synonyms

Tympanoneisiotes wetmorei( lapsus )

Tympanonesiotes is a somewhat doubtfully valid genus of the prehistoric pseudotooth birds. These were probably rather close relatives of either pelicans and storks, or of waterfowl, and are here placed in the order Odontopterygiformes to account for this uncertainty. [1]

Contents

Species and taxonomy

Only a single species, Tympanonesiotes wetmorei, is known to date. The only known specimen (USNM 16809), a distal right tarsometatarsus end, was found in the Cooper River near Drum Island (Charleston) at Charleston, South Carolina (United States). At first it was believed to be from the Early Miocene Hawthorne Formation, but as it seems its actual age cannot be precisely determined: For one thing, no Hawthorne Formation deposits were known in the region where the fossil was found. However, close to its type locality, fossils of Late Miocene animals have been found reworked from a now-eroded layer of rock into older deposits, such as the Chattian (Late Oligocene) sediments of the Cooper or Chandler Bridge Formation where the specimen of T. wetmorei was presumably found. The much-worn pseudotooth bird bone may also be such a reworked specimen. [2]

The genus' scientific name references the type locality: it is derived from Ancient Greek tympanon (drum) + nesiotes (islander). The specific name honors the famous ornithologist Alexander Wetmore; thus the scientific name means roughly "Alexander Wetmore's Drum Island bird". [3]

Description

The bone is not very well preserved; for most of its length only the anterior surface remains. What remains of the trochleae is still preserved in good detail however. Altogether, the bone is very similar to that of the sympatric and probably contemporary Palaeochenoides mioceanus , only appearing a bit more albatross-like. The spread of the toes must have resembled that found in a fulmar quite a lot, by contrast. The thin-walled bone has a second toe trochlea that attaches notably kneewards from the others and is angled slightly outwards while the hallux was vestigial or missing, as is typical for the pseudotooth birds. The fossil is about one-quarter smaller than that of Palaeochenoides, with a maximum end width of 24.5 mm (0.96 in) (as far as the trochleae are preserved), and a shaft that is 16.1 mm (0.63 in) wide near the point where it flares into the trochleae. It was thus about half again as large as "Odontoptila inexpectata" [4] from the Late Paleocene/Early Eocene of the Ouled Abdoul Basin (Morocco), i.e. around the size of the Early Eocene Odontopteryx toliapica from England or slightly bigger, or about the size of a great albatross (Diomedea) of our time. If the Tympanonesiotes fossil is indeed of Miocene age, it would be among the very few [5] pseudotooth birds known from the Neogene that was not of immense size. [6]

Systematics

T. wetmorei was initially placed in the presumed pelecaniform family Cyphornithidae, which had been placed in the "pelecaniform" suborder Cladornithes, together with two other misidentified pseudotooth birds Palaeochenoides and the family's type genus Cyphornis . The type genus of that supposed suborder, the enigmatic Late Oligocene Cladornis from the Argentinian part of Patagonia, like the present species is only known from a distal right tarsometatarsus end. This was believed to be reminiscent of the (then still undescribed) Tympanonesiotes, and thus it was argued that all four genera were closely related. But Cladornis is more generally held to be a terrestrial bird of unclear affiliations rather than a seabird nowadays, and the Cladornithes are not used anymore by recent authors. [7]

As regards the supposed Cyphornithidae, most if not all pseudotooth birds placed there are probably closely related to the better-known Pelagornis , type genus of the family Pelagornithidae. And even if Cyphornis is the senior synonym of Palaeochenoides and Tympanoneisiotes (which is not overly likely), according to the rules of zoological nomenclature the family name Pelagornithidae would not be affected. Thus Cyphornithidae would almost certainly be a junior synonym of Pelagornithidae even if the pseudotooth birds are (as some have proposed) divided into several families rather than being all placed in the Pelagornithidae as is usual nowadays as Cyphornis, Osteodontornis , Palaeochenoides, Pelagornis and perhaps Tympanoneisiotes appear to be very closely related and are probably part of a monophyletic lineage of (usually) giant pseudotooth birds. [8]

Footnotes

  1. Bourdon (2005), Mayr (2009: p.59)
  2. Hopson (1964), Olson (1985: pp.196-197), Mayr (2009: p.58)
  3. Hopson (1964)
  4. Only published in a thesis, and hence a nomen nudum ; also a junior homonym of the geometer moth genus Odontoptila and unavailable for the bird. Formerly "Odontopteryx n. sp. 1": ICZN (1999), Bourdon (2005)
  5. Contra Mayr (2009: p.59), "Pseudodontornis" stirtoni from the Neogene of New Zealand was also fairly small by pseudotooth bird standards: Scarlett (1972)
  6. Hopson (1964), Bourdon (2005), Mayr (2009: p.59)
  7. Brodkorb (1963: pp. 264-265), Hopson (1964), Olson (1985: pp. 193,195-197), Mayr (2009: pp.203-204)
  8. Olson (1985: pp. 195-197), Mlíkovský (2002: p.81), Mayr (2009: pp. 58-59)

Related Research Articles

<span class="mw-page-title-main">Gaviiformes</span> Order of birds

Gaviiformes is an order of aquatic birds containing the loons or divers and their closest extinct relatives. Modern gaviiformes are found in many parts of North America and northern Eurasia, though prehistoric species were more widespread.

<span class="mw-page-title-main">Loon</span> Family of birds

Loons or divers are a group of aquatic birds found in much of North America and northern Eurasia. All living species of loons are members of the genus Gavia, family Gaviidae and order Gaviiformes.

<span class="mw-page-title-main">Darter</span> Family of birds

The darters, anhingas, or snakebirds are mainly tropical waterbirds in the family Anhingidae, which contains a single genus, Anhinga. There are four living species, three of which are very common and widespread while the fourth is rarer and classified as near-threatened by the IUCN. The term snakebird is usually used without any additions to signify whichever of the completely allopatric species occurs in any one region. It refers to their long thin neck, which has a snake-like appearance when they swim with their bodies submerged, or when mated pairs twist it during their bonding displays. "Darter" is used with a geographical term when referring to particular species. It alludes to their manner of procuring food, as they impale fishes with their thin, pointed beak. The American darter is more commonly known as the anhinga. It is sometimes called "water turkey" in the southern United States; though the anhinga is quite unrelated to the wild turkey, they are both large, blackish birds with long tails that are sometimes hunted for food.

<span class="mw-page-title-main">Anseriformes</span> Order of water birds

Anseriformes is an order of birds also known as waterfowl that comprises about 180 living species of birds in three families: Anhimidae, Anseranatidae, and Anatidae, the largest family, which includes over 170 species of waterfowl, among them the ducks, geese, and swans. Most modern species in the order are highly adapted for an aquatic existence at the water surface. With the exception of screamers, males have penises, a trait that has been lost in the Neoaves. Due to their aquatic nature, most species are web-footed.

<span class="mw-page-title-main">Mousebird</span> Order of birds

The mousebirds are birds in the order Coliiformes. They are the sister group to the clade Cavitaves, which includes the Leptosomiformes, Trogoniformes (trogons), Bucerotiformes, Piciformes and Coraciformes. This group is now confined to sub-Saharan Africa, and it is the only bird order confined entirely to that continent, with the possible exception of turacos which are considered by some as the distinct order Musophagiformes, and the cuckoo roller, which is the only member of the order Leptosomiformes, and which is found in Madagascar but not mainland Africa. Mousebirds had a wider range in the Paleogene, with a widespread distribution in Europe and North America during the Paleocene.

<i>Anas</i> Genus of birds

Anas is a genus of dabbling ducks. It includes the pintails, most teals, and the mallard and its close relatives. It formerly included additional species but following the publication of a molecular phylogenetic study in 2009 the genus was split into four separate genera. The genus now contains 31 living species. The name Anas is the Latin for "duck".

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

Osteodontornis is an extinct seabird genus. It contains a single named species, Osteodontornis orri, which was described quite exactly one century after the first species of the Pelagornithidae was. O. orri was named after Santa Barbara Museum of Natural History paleontologist Phil C. Orr, for his recognition of the importance of the specimen.

Paraptenodytes brodkorbi is a proposed, but possibly invalid, species of extinct penguin in the genus Paraptenodytes. The bird was probably about the size of a king penguin. Known material is limited to a single humerus, Early Miocene in age, found in the Monte León Formation near Puerto San Julián in Santa Cruz Province, Argentina. It exists as an unnumbered specimen in the collection of the Museo Argentino de Ciencias Naturales.

<span class="mw-page-title-main">Pelagornithidae</span> Extinct family of seabirds

The Pelagornithidae, commonly called pelagornithids, pseudodontorns, bony-toothed birds, false-toothed birds or pseudotooth birds, are a prehistoric family of large seabirds. Their fossil remains have been found all over the world in rocks dating between the Early Paleocene and the Pliocene-Pleistocene boundary.

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

Odontopteryx is a genus of the extinct pseudotooth birds or pelagornithids. These were probably rather close relatives of either pelicans and storks, or of waterfowl, and are here placed in the order Odontopterygiformes to account for this uncertainty.

Caspiodontornis is a genus of the prehistoric pseudotooth birds of somewhat doubtful validity. These were probably rather close relatives of either pelicans and storks, or of waterfowl, and are here placed in the order Odontopterygiformes to account for this uncertainty.

Cyphornis is a genus of the prehistoric pseudotooth birds. These were probably rather close relatives of either pelicans and storks, or of waterfowl, and are here placed in the order Odontopterygiformes to account for this uncertainty.

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

Dasornis is a genus of prehistoric pseudotooth birds. These were probably close relatives of either pelicans and storks or waterfowl; they are placed in the order Odontopterygiformes to account for this uncertainty.

Gigantornis eaglesomei is a very large prehistoric bird described from a fragmentary specimen from the Eocene of Nigeria. It was originally described as a representative of the albatross family, Diomedeidae, but was later referred to the pseudotooth or bony-toothed bird family, Pelagornithidae. Gigantornis is one of the largest pseudotooth birds, with an inferred wingspan of about 6 m (20 ft) it is among the largest birds ever.

Palaeochenoides is a genus of the prehistoric pseudotooth birds of somewhat doubtful validity. These were probably rather close relatives of either pelicans and storks, or of waterfowl, and are here placed in the order Odontopterygiformes to account for this uncertainty.

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

Pelagornis is a widespread genus of prehistoric pseudotooth birds. These were probably rather close relatives of either pelicans and storks, or waterfowl, and are placed here in the order Odontopterygiformes to account for this uncertainty.

Pseudodontornis is a rather disputed genus of the prehistoric pseudotooth birds. The pseudotooth birds or pelagornithids were probably rather close relatives of either pelicans and storks, or of waterfowl, and are here placed in the order Odontopterygiformes to account for this uncertainty. Up to five species are commonly recognized in this genus.

Macrodontopteryx is a genus of the prehistoric pseudotooth birds of somewhat doubtful validity. These animals were probably rather close relatives of either pelicans and storks, or of waterfowl, and are here placed in the order Odontopterygiformes to account for this uncertainty.

<i>Phocavis</i> Extinct genus of Plotopteridae

Phocavis is an extinct genus of flightless seabird, belonging to the family Plotopteridae, and distantly related with modern cormorants. Its fossils, found in the Keasey Formation in Oregon, are dated from the Late Eocene.

References