Cryptogyps

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Cryptogyps
Temporal range: Pleistocene, 0.77–0.050  Ma
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Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Aves
Order: Accipitriformes
Family: Accipitridae
Subfamily: Aegypiinae
Genus:† Cryptogyps
Mather, Lee & Worthy, 2022
Species:
†C. lacertosus
Binomial name
†Cryptogyps lacertosus
(de Vis, 1905)
Synonyms [2]
  • “Taphaetus” lacertosus de Vis, 1905

Cryptogyps is an extinct genus of Old World vulture from the Pleistocene of Australia. It was relatively small for a vulture but still larger than the extant wedge-tailed eagle. Originally described as an eagle in 1905 (under the binomial name Taphaetus lacertosus), in 2022 it was reidentified as a vulture, the first known example from the continent. Phylogenetic analysis suggests it either being a sister species to the extant, widespread Eurasian vulture genus Gyps or as a more basal member of the subfamily. The identification of Cryptogyps as a vulture solves a longstanding mystery about the lack of specialized lineages of large scavenging birds in Australia despite being present on every other continent aside from Antarctica. It is likely that Cryptogyps went extinct towards the end of the Pleistocene due to the disappearance of the megafauna it depended on for carrion. The genus contains a single species, C. lacertosus.

Contents

History and naming

Cryptogyps has a long and complicated taxonomic history. It was initially described as “Taphaetus” lacertosus by Charles Walter De Vis in 1905 based on the lower part of a humerus and a quadrate bone of Middle-Late Pleistocene age, found around Kalamurina in South Australia. The assignment of the fossil material to "Taphaetus" by De Vis was problematic, as the genus had been declared a junior synonym of Uroaetus by De Vis himself earlier that same year. Later still Uroaetus was deemed synonymous with Aquila , as the type specimen was found to be identical to the modern wedge-tailed eagle. Subsequently, the genus "Taphaetus" was unavailable in accordance with the rules of the International Code of Zoological Nomenclature (ICZN). In 1974 Gerard Frederick van Tets suggested that "T." lacertosus was a member of the genus Icthyophaga (now synonymous with Haliaeetus ) and designated the humerus as the lectotype before later placing the species in the subfamily Gypaetinae, which at the time contained all old-world vultures. A thorough examination of the lectotype humerus was published by Mather, Lee and Worthy in 2022 in order to determine if the material represented a distinct taxon. Their research concluded that the fossil not only belonged to a distinct genus and species of bird of prey, but also that it was a type of aegypiine vulture rather than a type of eagle. To reflect all this, the genus Cryptogyps was coined. Aside from the type material, fossils of indeterminate Pleistocene age were discovered in the Wellington Caves (New South Wales) and Nullarbor Plain (Western Australia). [2] [3] A year later additional material from the Green Waterhole, also known as the Fossil Cave, in the Tantanoola District (South Australia) was described and referred to Cryptogyps. Other material referred to Cryptogyps in the same study includes fossils from the Leaena’s Breath Cave (Nullarbor Plain), Wellington Caves and the Walli Caves. [4]

The name Cryptogyps is a combination of the Ancient Greek "kryptos" and "gyps", meaning "hidden" and "vulture" respectively. This name reflects the fact that despite having been known for over a century, the animal's identity as a vulture had remained largely unknown. Additionally, the name also contains the word "crypt", which as an underground burial site matches the discovery of fossil material in caves. [2] The species name means "powerful". [5] [3] [6]

Description

Despite being close in size to the large wedge-tailed eagle (Aquila audax), Cryptogyps had more robust wings. [4] It's described unusually small for an aegypiine vulture, with only the extant hooded vulture (Necrosyrtes monachus) being smaller. [2] Multiple different approaches were taken to determine the mass of Cryptogyps, with values derived from the humeral articular facet length of the coracoid and the shaft width resulting in an estimated weight of 11–12 kg (24–26 lb). Total length meanwhile recovered a much lower value of only 3 kg (6.6 lb). Mather and colleagues reason that this massive difference is likely caused by the wide range of bird species that the used algorithm was based on. They argue that the true weight of Cryptogyps was likely somewhere in between these results, concluding that Cryptogyps most likely weighed between 3–6 kg (6.6–13.2 lb), a similar range to that of the modern wedge-tailed eagle. [4]

Phylogeny

Initially three phylogenetic trees were recovered using a combination of both morphological and molecular data. These analysis provide moderate support for the fact that Cryptogyps was part of the clade containing aegypiine vultures and serpent eagles, with strong support for its placement in the former. The key traits that appear to place Cryptogyps in this subfamily appear to be two synapomorphies of the tarsometatarsus. Within vultures, it may have been closely related to the modern genus Gyps , which contains the modern griffon vultures. However this relationship is only poorly supported and later analysis conducted after the discovery of Dynatoaetus find different placements. In Mather et al. (2023), Cryptogyps was recovered in a more basal position outside the aegypiine crown but more derived than Dynatoaetus. The Bayesian analysis of the same publication recovers it in an even more basal position, as a sister taxon to the clade containing aegypiine vultures, serpent eagles, booted eagles, forest eagles, true hawks, buzzards, sea eagles and kites. However, this placement of Cryptogyps as its own separate branch was only weakly supported. [7] The phylogenetic analysis conducted following the description of the second species of Dynatoaetus mirror the results of Mather's prior work, finding Cryptogyps as nesting just outside the modern aegypiine vultures while also strenghtening this conclusion through the new material. [4]

The two phylogenetic trees below show the strict consensus trees of both Mather, Lee and Worthy (2022) [2] and Mather et al. (2023). [7]

Paleobiology

The legs of Cryptogyps match the overall morphology of the generalized aegypiine hindlimb, with only shallow groves indicative of relatively weak musculature. [1] Although the morphology is still somewhat better developed than in extant vultures, it is nowhere near as pronounced as in active predators such as the wedge-tailed eagle. It is thus likely that Cryptogyps were primarily scavengers, feeding upon dead or dying Australian megafauna and at times traveled great distances while searching for carrion. [2] However, a later study also concluded that the bones of Cryptogyps are less pneumatized than those of modern vultures, which indicates that it was not as well adapted at long-distance soaring as extant species. [4] Assuming that the size of this vulture correlates with its general feeding preference, as observed in its modern relatives, Cryptogyps may have been a "gulper" or "ripper" type scavenger. This means that it may have either fed on the soft parts of carcasses, such as the internal organs, or that it may have ripped open flesh and skin. Regardless of the specifics, this would have provided a valuable ecological service by reducing disease transmission and facilitating energy flow. While nothing conclusive can be said about the specifics of its behavior, the hypothesis that Cryptogyps is related to extant griffon vultures could mean that they at times gathered in large numbers. Such social groups formed during scavenging could have provided multiple advantages, such being an aid during foraging while also driving off other scavengers. [2] [3] Another possibility is that Cryptogyps could have been a solitary animal or that it foraged in pairs. [5] Still, Cryptogyps may not have been uncontested as a scavenger. In addition to the native marsupials like thylacines and Sarcophilus as well as monitor lizards, [4] the contemporary Dynatoaetus was a notably larger bird and, assuming that it behaved in a similar fashion to the extant wedge-tailed eagle, may have not been above scavenging when the opportunity presented itself. The shere size of Dynatoaetus may have allowed it to successfully dominate over the smaller Cryptogyps should the two have fought over a single carcass. [7] Similar interactions are known from Africa, where large raptors would occasionally follow vultures and drive them away from carcasses. [2]

Given the discovery of remains across Australia, from Western Australia to New South Wales, it is possible that Cryptogyps may have been a widespread species across the continent, foraging in grassland and open woodland environments. Following the extinction of most Australian megafauna during the Quaternary extinction event about 50,000 years ago, Cryptogyps may have also gone extinct due to a lack of carrion to feed on. While large bodied kangaroos would later grow in numbers and spread into environments they did not previously inhabit, this shift may have come too late for Cryptogyps. The extinction of Cryptogyps is thought to have allowed the wedge-tailed eagle to more easily exploit this resource and become Australia's primary scavenging bird species given the lack of specialised competition. [2] [1] [5] [7] [4]

Related Research Articles

<span class="mw-page-title-main">Vulture</span> Common name for a type of bird

A vulture is a bird of prey that scavenges on carrion. There are 23 extant species of vulture. Old World vultures include 16 living species native to Europe, Africa, and Asia; New World vultures are restricted to North and South America and consist of seven identified species, all belonging to the Cathartidae family. A particular characteristic of many vultures is a bald, unfeathered head. This bare skin is thought to keep the head clean when feeding, and also plays an important role in thermoregulation.

<span class="mw-page-title-main">Eagle</span> Large carnivore bird

Eagle is the common name for the golden eagle, bald eagle, and other birds of prey in the family Accipitridae. Eagles belong to several groups of genera, some of which are closely related. True eagles comprise the genus Aquila. Most of the 68 species of eagles are from Eurasia and Africa. Outside this area, just 14 species can be found—two in North America, nine in Central and South America, and three in Australia.

<span class="mw-page-title-main">Bird of prey</span> Paraphyletic group of birds

Birds of prey or predatory birds, also known as raptors, are hypercarnivorous bird species that actively hunt and feed on other vertebrates. In addition to speed and strength, these predators have keen eyesight for detecting prey from a distance or during flight, strong feet with sharp talons for grasping or killing prey, and powerful, curved beaks for tearing off flesh. Although predatory birds primarily hunt live prey, many species also scavenge and eat carrion.

<span class="mw-page-title-main">Haast's eagle</span> Extinct species of bird

Haast's eagle is an extinct species of eagle that lived in the South Island of New Zealand, commonly accepted to be the pouākai of Māori legend. It is the largest eagle known to have existed, with an estimated weight of 15 kilograms, compared to the next-largest and extant harpy eagle, at up to 9 kg (20 lb). Its massive size is explained as an evolutionary response to the size of its prey, the flightless moa, the largest of which could weigh 230 kg (510 lb). Haast's eagle became extinct around 1400, following the arrival of the Māori who hunted moa to extinction, introduced the Pacific rat, and destructed large tracts of forest by fire.

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

The Accipitridae is one of the three families within the order Accipitriformes, and is a family of small to large birds of prey with strongly hooked bills and variable morphology based on diet. They feed on a range of prey items from insects to medium-sized mammals, with a number feeding on carrion and a few feeding on fruit. The Accipitridae have a cosmopolitan distribution, being found on all the world's continents and a number of oceanic island groups. Some species are migratory. The family contains 255 species which are divided into 70 genera.

<span class="mw-page-title-main">Black vulture</span> New World vulture

The black vulture, also known as the American black vulture, Mexican vulture, zopilote, urubu, or gallinazo, is a bird in the New World vulture family whose range extends from the southeastern United States to Perú, Central Chile and Uruguay in South America. Although a common and widespread species, it has a somewhat more restricted distribution than its compatriot, the turkey vulture, which breeds well into Canada and all the way south to Tierra del Fuego. It is the only extant member of the genus Coragyps, which is in the family Cathartidae. Despite the similar name and appearance, this species is unrelated to the Eurasian black vulture, an Old World vulture, of the family Accipitridae. For ease of locating animal corpses, black vultures tend to inhabit relatively open areas with scattered trees, such as chaparral, in addition to subtropical forested areas and parts of the Brazilian pantanal.

<span class="mw-page-title-main">Aegypiinae</span> Subfamily of birds

Aegypiinae is one of two subfamilies of Accipitridae that are referred to as Old World vultures, the other being the Gypaetinae. They are not closely related to the Gypaetinae, and are instead thought to be the sister group to the serpent-eagles (Circaetinae).

<i>Gyps</i> Genus of birds

Gyps is a genus of Old World vultures that was proposed by Marie Jules César Savigny in 1809. Its members are sometimes known as griffon vultures. Gyps vultures have a slim head, a long slender neck with downy feathers, and a ruff around the neck formed by long buoyant feathers. The crown of their big beaks is a little compressed, and their big dark nostrils are set transverse to the beak. They have six or seven wing feathers, of which the first is the shortest and the fourth the longest.

<i>Thylacoleo</i> Extinct genus of marsupials

Thylacoleo is an extinct genus of carnivorous marsupials that lived in Australia from the late Pliocene to the Late Pleistocene, often known as marsupial lions. They were the largest and last members of the family Thylacoleonidae, occupying the position of apex predator within Australian ecosystems. The largest and last species, Thylacoleo carnifex approached the weight of a lioness. The estimated average weight for the species ranges from 101 to 130 kg.

Aiolornis incredibilis is an extinct species of teratorn bird from the western United States. Only fragmentary remains have been found, which are dated between the Early Pliocene (Zanclean) and Late Pleistocene. First described as Teratornis incredibilis by Howard in 1952 based on a cuneiform bone, the species has been moved to the new genus Aiolornis by Campbell, Scott and Springer in 1999. The generic name is derived from the ancient Greek words aiolus and ornis. Aiolus refers to the Greek god of the wind, and ornis means "bird". The specific name incredibilis means ‘incredible’. A. incredibilis is lesser-known than its close relative, Teratornis merriami, even though A. incredibilis was significantly larger. It presumably became extinct at the same time as the other megafauna in North America.

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

Teratornithidae is an extinct family of very large birds of prey that lived in North and South America from the Late Oligocene to Late Pleistocene. They include some of the largest known flying birds.

<span class="mw-page-title-main">Giant koala</span> Extinct species of marsupial

The giant koala is an extinct arboreal marsupial which existed in Australia during the Pleistocene epoch. Phascolarctos stirtoni was about one-third larger than the contemporary koala, P. cinereus, and has an estimated weight of 13 kg (29 lb), which is the same weight as a large contemporary male koala.

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

Teratornis was a genus of huge North American birds of prey—the best-known of the teratorns—of which, two species are known to have existed: Teratornis merriami and Teratornis woodburnensis. A large number of fossil and subfossil bones, representing more than 100 individuals, have been found in locations in California, Oregon, southern Nevada, Arizona, and Florida, though most are from the Californian La Brea Tar Pits. All remains except one Early Pleistocene partial skeleton from the Leisey Shell Pit near Charlotte Harbor, Florida date from the Late Pleistocene, with the youngest remains dating from the Pleistocene–Holocene boundary.

<i>Cathartes</i> Genus of birds

The genus Cathartes includes medium-sized to large carrion-feeding birds in the New World vulture (Cathartidae) family. The three extant species currently classified in this genus occur widely in the Americas. There is one extinct species known from the Quaternary of Cuba.

<i>Buteogallus</i> Genus of birds

Buteogallus is a genus of birds of prey in the family Accipitridae. All members of this genus are essentially neotropical, but the distribution of a single species extends slightly into the extreme southwestern United States. Many of the species are fond of large crustaceans and even patrol long stretches of shore or riverbank on foot where such prey abounds, but some have a rather different lifestyle. Unlike many other genera of raptor, some members are referred to as "hawks", and others as "eagles".

Buteogallus borrasi is a species of giant buteonine hawk which went extinct in the early Holocene. Formerly endemic to Cuba, this huge bird of prey probably fed on Pleistocene megafauna. Little is known about its appearance and ecology, so no common name has been given.

Buteogallus daggetti, occasionally called "Daggett's eagle" or the "walking eagle", is an extinct species of long-legged hawk which lived in southwest North America during the Pleistocene. Initially believed to be some sort of carrion-eating eagle, it was for some time placed in the distinct genus Wetmoregyps, named for Alexander Wetmore. It probably resembled a larger version of the modern-day savanna hawk, with its long legs possibly used like the secretarybird of Africa to hunt for small reptiles from a safe distance. It died out about 13,000 years ago.

Aquila bullockensis is an extinct species of large true eagles in the family Accipitridae. A. bullockensis is related to the living species A. audax to which it might be ancestral. The species is solely known from the distal end of a right humerus found in the Middle Miocene, Bullock Creek deposits in Australia. A. bullockensis is the oldest confirmed record of the genus Aquila in Australia, and possibly in the world.

<i>Xenorhynchopsis</i> Extinct genus of bird

Xenorhynchopsis is an extinct genus of flamingo from the Pliocene to Pleistocene Lake Eyre basin of Australia. Initially described as species of stork, the two known Xenorhynchopsis species are vastly different in size. X. minor is the older and small of the two species, ranging from the Pliocene to Pleistocene and being described as having reached a size smaller than that of the lesser flamingo. X. tibialis meanwhile appears to have been restricted to Pleistocene strata and was notably bigger, being counted as one of the biggest known flamingos in the fossil record.

<i>Dynatoaetus</i> Extinct genus of birds of prey

Dynatoaetus is an extinct genus of large bird of prey from the Pleistocene of Australia. It is among the largest known raptors of the region, second only to the Haast's eagle of New Zealand, with estimates suggesting a weight of up to 12 kg (26 lb). Although most closely related to modern vultures, it shows clear adaptations towards an active predatory lifestyle in the form of robust, powerful talons. This may either hint at it retaining these ancestral features from the closely related serpent eagles or show that it convergently evolved these features as it took on a similar lifestyle. Due to their size and robust bones, it is thought that Dynatoaetus would have been capable of taking large prey items like kangaroos, giant wombats and flightless birds. There are two species within the genus, the type species Dynatoaetus gaffae and the somewhat smaller Dynatoaetus pachyosteus, both of which inhabited the same part of Australia at the same time.

References

  1. 1 2 3 "Scientists picking over ice age bones discover vultures once soared in Australia's skies". the Guardian. 2022-07-19. Retrieved 2022-07-22.
  2. 1 2 3 4 5 6 7 8 9 Mather EK, Lee MS, Worthy TH (2022). "A new look at an old Australian raptor places "Taphaetus" lacertosus de Vis 1905 in the Old World vultures (Accipitridae: Aegypiinae)". Zootaxa . 5168 (1): 1–23. doi: 10.11646/zootaxa.5168.1.1 . PMID   36101304.
  3. 1 2 3 Nield, David. "Ancient Fossil Fragment Revealed as The Only Vulture Ever Discovered in Australia". ScienceAlert. Retrieved 2022-07-20.
  4. 1 2 3 4 5 6 7 Mather, Ellen K.; Lee, Michael S. Y.; Fusco, Diana A.; Hellstrom, John; Worthy, Trevor H. (2023-11-19). "Pleistocene raptors from cave deposits of South Australia, with a description of a new species of Dynatoaetus (Accipitridae: Aves): morphology, systematics and palaeoecological implications". Alcheringa: An Australasian Journal of Palaeontology: 1–32. doi: 10.1080/03115518.2023.2268780 . ISSN   0311-5518.
  5. 1 2 3 Mather, Ellen K. "It was long thought these fossils came from an eagle. Turns out they belong to the only known vulture species from Australia". The Conversation. Retrieved 2022-07-22.
  6. ↑ "Australian vulture emerges from fossil record". ScienceDaily. Retrieved 2022-07-22.
  7. 1 2 3 4 Mather, E.K.; Lee, M.S.Y.; Camens, A.B.; Worthy, T.H. (2023). "A giant raptor (Aves: Accipitridae) from the Pleistocene of southern Australia". Journal of Ornithology. doi: 10.1007/s10336-023-02055-x . S2CID   257575533.
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