Adelalopus

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Adelalopus
Temporal range: Rupelian
Scientific classification Red Pencil Icon.png
Kingdom: Animalia
Phylum: Chordata
Class: Aves
Order: Phoenicopteriformes
Family: Palaelodidae
Genus: Adelalopus
Mayr & Smith, 2002
Type species
Adelalopus hoogbutseliensis
Mayr & Smith, 2002

Adelalopus is an extinct genus of palaelodid bird from the lowermost Oligocene of Belgium. It is the oldest member of its family and the largest known palaelodid from Europe, slightly larger than Megapaloelodus goliath . It contains a single species, Adelalopus hoogbutseliensis.

Contents

History and naming

The remains of Adelalopus were discovered at the locality of Hoogbutsel, Belgium, approximately 30 km (19 mi) east of Brussels and are stored at the Museum of Natural Sciences of Belgium. The type specimen IRScNB Av 71 consists of an incomplete furcula, parts of a coracoid, a scapula, the distal end of an ulna and the shaft of a radius as well as an incomplete tarsometatarsus. A second specimen (IRScNB Av 72) is referred to the genus, consisting of the extremitas omalis of the left coracoid. The same element is present for the right coracoid in the holotype. All material included in the type specimen is considered to be from a single individual based on the proximity of the bones, their size and their similar surface texture. The referred coracoid was found in a different box, but may potentially have belonged to the same individual as well. [1]

The name Adelalopus is an anagram of Palaelodus , a relative of the genus. The species name references the type locality. [1]

Description

The furcula has a wide U-shape and on the caudal surface of the extremitas sternalis there is a marked depression like in Palaelodus. [2] Unlike in Palaeolodus however the center of this element contains a deep and elongated cavity, which is regarded as one of the genus' diagnostic features. The apophysis of the wishbone is larger and better developed than in modern flamingos but incomplete. The coracoid is similar to that of Megapaloelodus , with the facies that articulates with the clavicle overhanging two pits separated from each other by a bulge. These same bits are weak in Palaelodus and missing entirely in modern flamingos. The medial and lateral sides of the cotyla scapularis are not sharply differentiated and the foramen for the supracoracoid nerve is well-developed and elliptical like in basal-anseriforms and phoenicopteriforms. The scapula is short with a slender shaft similar to Palaeolodus. The incomplete nature of the ulna makes comparison difficult, but it generally resembles what is expected from palaelodids and modern flamingos. Although fragmentary, the tarsometatarsus is diagnostic. Its cross section is rectangular like in modern flamingos and not compressed like in other palaelodids. The distal vascular foramen is larger and longer than in either palaelodids or phoenicopterids and in this state more closely resembles the Eocene bird Juncitarsus , which has been recovered as either a basal member of Mirandornithes or a stem-Phoenicopteriform. The trochlea of the second digit faces plantar like typical for the group and was positioned higher than the trochlea of the following two toes. As seen in Palaelodus, this trochlea was located further up than in modern flamingos. [1]

Adelalopus is slightly larger than Megapaloelodus goliath , making it the largest member of the Palaelodidae. The individual bones are identical in size to the extant coscoroba swan from South America. [1]

Paleoecology

The Hoogbutsel locality where the remains of Adelalopus were found is thought to represent what was once the shore of a lagoon. With the locality being considered to be early Oligocene in age, Adelalopus would be among the earliest known palaelodids. The function of the deep cavity located on the furcula is not known, it is however thought to be too large to be a simple pneumatic foramen and too small to enclose a tracheal loop. [1]

Related Research Articles

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

Palaelodus is an extinct genus of bird of the Palaelodidae family, distantly related to flamingos. They were slender birds with long, thin legs and a long neck resembling their modern relatives, but likely lived very different livestyles. They had straight, conical beaks not suited for filter feeding and legs showing some similarities to grebes. Their precise lifestyle is disputed, with researchers in the past suggesting they may have been divers, while more recent research suggests they may have used their stiff toes as paddles for swimming while feeding on insect larvae and snails. This behavior may have been key in later phoenicopteriforms developing filterfeeding bills. The genus includes between five to eight species and is found across Europe, Australia, New Zealand, Asia and possibly South America. However some argue that most of the taxa named from Europe simply represent differently sized individuals of one single species. Palaelodus was most abundant during the Late Oligocene to Middle Miocene periods, but isolated remains from Australia indicate that the genus, or at least a relative, survived until the Pleistocene.

Megapaloelodus is an extinct genus of birds distantly related to flamingos. It belongs to the same family as the closely related genus Palaelodus, but was more specialized. Megapaloelodus represents a specialization of the lifestyle of Palaelodus, which apparently was more like a wading duck in behavior – long-legged but still able to swim with ease, possibly even diving a lot – than a modern flamingo. Megapaloelodus, on the other hand, seems to have been evolved into a true wading bird, convergent with the true flamingos.

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

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.

Phoeniconotius is an extinct genus of flamingo that lived in Australia from the late Oligocene to the early Miocene. Unlike modern flamingos and the contemporary Phoenicopterus novaehollandiae, it was likely less well adapted for swimming and deep water wading. Phoeniconotius was a robust flamingo with bones more massive than those of the modern greater flamingo. Only a single species is recognized, Phoeniconotius eyrensis.

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

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<span class="mw-page-title-main">Palaelodidae</span> Extinct family of birds

Palaelodidae is a family of extinct birds in the group Phoenicopteriformes, which today is represented only by the flamingos. They have been described as "swimming flamingos."

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

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<i>Zhongjianosaurus</i> Extinct genus of reptiles

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

Allgoviachen is an extinct genus of anatid bird from the Late Miocene (Tortonian) Hammerschmiede clay pits of Bavaria, Germany. The genus contains a single species, A. tortonica, known from bones belonging to the left leg.

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References

  1. 1 2 3 4 5 Mayr, G.; Smith, R. (2002). "Avian remains from the lowermost Oligocene of Hoogbutsel (Belgium)" (PDF). Bulletin de l'Institut royal des Sciences naturelles de Belgique, Sciences de la Terre. 72: 139–150. ISSN   0374-6291.
  2. Mayr, G.; De Pietri, V.L. (2013). "A goose-sized anseriform bird from the late Oligocene of France: the youngest record and largest species of Romainvilliinae". Paläontol Z. 87 (3): 423–430. doi:10.1007/s12542-013-0165-5. S2CID   84593598.