Dynatoaetus gaffae gen. et sp. nov. (1 Viewer)

[Fred Ruhe]

Ellen K. Mather, Michael S. Y. Lee, Aaron B. Camens & Trevor H. Worthy, 2023
A giant raptor (Aves: Accipitridae) from the Pleistocene of southern Australia

Journal of Ornithology
doi:10.1007/s10336-023-02055-x. ISSN 2193-7192

Abstract and free pdf: A giant raptor (Aves: Accipitridae) from the Pleistocene of southern Australia - Journal of Ornithology

The giant accipitrid Dynatoaetus gaffae gen. et sp. nov. is described from existing and newly collected material. Initial fossil remains were collected from Mairs Cave (Flinders Ranges, South Australia) in 1956 and 1969, and comprised a sternum, distal humerus and two ungual phalanges. A further 28 bones from this individual—including the neurocranium, vertebrae, furculum, and additional wing and leg bones, most of which were incomplete—were discovered at the site in 2021. This allowed identification of additional fossils from the same species in collections from Cooper Creek (Lake Eyre Basin, SA), Victoria Fossil Cave (Naracoorte, SA) and Wellington Caves (Wellington, NSW). Dynatoaetus has variable similarity across elements to those of living species in the Perninae, Gypaetinae, Circaetinae and Aegypiinae. Parsimony and Bayesian phylogenetic analyses of combined morphological and DNA data resolved it as the immediate sister-group to the Aegypiinae within the Circaetinae + Aegypiinae clade. The robust and eagle-like morphology of the lower hindlimbs suggest that the species was a predator, rather than a scavenger, and thus functionally similar to large circaetines such as the Philippine Eagle Pithecophaga jefferyi. Furthermore, this new species is the largest known bird of prey from Australia, much larger than the modern Wedge-Tailed Eagle Aquila audax. It is outsized in Australasia only by female Hieraaetus moorei (the extinct Haast’s Eagle from New Zealand). It is inferred to have been Australia’s top terrestrial avian predator during the Pleistocene, ranging from arid inland Australia to the more temperate coast, and likely became extinct around the time of the megafaunal mass extinction which peaked around 50 Ka. Its extinction in the late Pleistocene, along with the recently described scavenging vulture Cryptogyps lacertosus, marked a distinct decline in the diversity and function of Australia’s raptor guild


Enjoy,

Fred

 

[Fred Ruhe]

Systematic palaeontology

Accipitriformes Vieillot 1816
Accipitridae Vigors 1824
Dynatoaetus gen. nov.
Zoobank ID : urn: lsid: zoobank.orgub:236A128E-4FFD-4B0D-BEC1-3F6DF133E390

Diagnosis: A large accipitrid distinguishable from other genera by the following combination of characters: a neurocranium that is (1) relatively short and wide compared to Aquila audax; (2) has the line linking the tip of the processus zygomaticus to the ventral tip of the processus paroccipitalis aligned about 45 degrees to the plane of basioccipital-parasphenoidal plane and ventrally encloses a tympanic recess that is longer than high; (3) the condylus occipitalis is relatively large; (4) the mamillar tuberosities (tubercula basilaria) are robust, and prominent caudally; (5) the foramen magnum is near-perpendicular to the basioccipital plane (~ 10 degrees off perpendicular); (6) has prominent tubercula
for the insertion for m. pseudotemporalis superficialis on the facies orbitalis. A sternum with (7) distinct and prominently projecting processus labrum internum; (8) a spina externa that is narrower than the apex carinae; (9) a crista medialis carinae that does not extend to the base of the spina externa. A humerus with (10) a weakly ventrally projecting epicondylus ventralis; (11) the distance between the interior margin of the tuberculum supracondylare ventrale and the proximal tip of the condylus dorsalis is equal to that between the tip of the condylus dorsalis and the dorsal margin; and (12) a deep insertion pit for the distal head of the m. pronator profundus. An ulna with (13) a tuberculum carpale that has little prominence cranioventrally. A tarsometatarsus that (14) is robust; (15) has a trochlea metatarsi II that is broad and more distally elongate than trochlea metatarsi III; (16) has the trochleae metatarsorum II and IV with robust plantar flanges and with (17) the plantar openings of the foramen
vasculare proximale medialis positioned on the lateral side of the crista medialis hypotarsi; and (18) has the medial side of the shaft deeply excavated caudally by the fossa parahy- potarsalis medialis such that the medial margin is very thin.

Etymology: The genus name is a combination of the ancient Greek words δῠνᾰτός (dynatós), meaning strong, mighty, or powerful, and ᾱ̓ ετός (āetós) meaning eagle.

Type species: Dynatoaetus gaffae gen. et sp. nov.

Dynatoaetus gaffae gen. et sp. nov.
Zoobank genus ID: urn: lsid: zoobank org:act:83F0032D-776F-4903-AC60-247C464F811F
Zoobank species ID: urn: lsid: zoobank.org:act:CC30C4DD-BFB5-4FED-87D9-ACE9323896AE

Diagnosis: Same as genus.

Holotype: SAMA P.59525 neurocranium, fragments of the mandible, two cervical vertebrae, three thoracic vertebrae, anterior end of the synsacrum, two caudal vertebrae, left and right sides furculum, right scapula, proximal right humerus, distal left ulna, proximal right radius, left carpometacarpus, left proximal phalanx major digit [or phalanx proximalis digiti majoris], two ribs, a tibiotarsus shaft, right tarsometatarsus, proximal right fibula, right metatarsal and left pedal phalanx I of digit I, left pedal phalanges I and II of digit II, right pedal phalanx I of digit IV, and an ungual phalanx; collected by Mather, Camens, Worthy et al. 4 December 2021. Ungual phalanx SAMA P.19157 and sternum SAMA P.19158, collected by CEGSA [Cave Exploration Group (South Australia)] June 1956; distal left humerus SAMA P.14528, collected by H. Mincham, 1969; ungual phalanx SAMA P.17139, collected by B. Daily and
H. Mincham 1969—catalogue records “surface, under large rocks 60 yds in’’. All these specimens are part of a single skeleton.

Type locality and stratigraphy: Mairs Cave, Buckalowie Gorge, Flinders Ranges, SA, Australia, 32° 10′ 30 S, 138° 52′ 23 E (see Fig. 1). The bones of the Mairs Cave individual were 55 m from the entrance against the east wall of the main passage and were scattered between rocks over 3 m vertically and along the passage floor below the rockpile. It, therefore, was essentially a surface deposit and bones on
the floor were associated with extinct Pleistocene mammal species.

Age of holotype: Pleistocene (Upper or Chibanian, precise age unknown).

Referred material: Main Fossil Chamber, Victoria Fossil Cave, Naracoorte, SA, Australia, − 37.0429°, 140.8016°, Pleistocene (Chibanian)—Right femur SAMA P.41514, excavation details [in metric feet from origin; see Reed 2003] 64.5–67.0, R9–10, D/D − 0.5 to − 1.0; right distal tarsometatarsus preserving trochleae II and III SAMA P.28008, excavation details 60.5–62.5, R1–2, D/D − 0.5 to − 1.0. ‘Old Collection’, Wellington Caves, NSW, Australia, 32° 31’ S, 148° 51’ E, Pliocene–Pleistocene—right distal tibiotarsus AM F.106562, likely acquired by NSW Mining Department 1884–1917.
Cooper Creek, Waralamanko Waterhole (referred to as ‘Waralamanka Waterhole’ in Gaff [2002]), site A, Kutjitara Formation, Lower Cooper Fauna, Pleistocene—right distal tibiotarsus SAMA P.25218, specimen, currently unlocated, was depicted in Plates 5.1 and 5.2 Gaff (2002).

Etymology: The name ‘gaffae’ honours Priscilla Gaff, who first discussed the fossil material of this species in her 2002 thesis revising Australian accipitrids.

Comparisons with Australasian Pleistocene taxa

Dynatoaetus gaffae can be separated from the aegypiine Cryptogyps lacertosus by the following features: it is significantly larger than C. lacertosus; the distance between the proximal tip of the condylus dorsalis and the margin of the tuberculum supracondylare ventrale on the humerus is equal to the distance between the condylus dorsalis and the lateral margin of the face between the tuberculum supracondylare dorsale and the epicondylus dorsalis (greater in C. lacertosus); the tarsometatarsus is moderately elongate (stout in C. lacertosus), the sulcus hypotarsi is broad (narrow), the base of the cristae hypotarsi are connected to a flat ventral surface (connected to a raised ridge), the foramen vasculare proximale medialis is located lateral to the crista medialis hypotarsi (located medial to the crista), the impressiones retinaculi extensorii form two prominent ridges with a deepened depression between them (ridges absent, no deepening), and the medial shaft is very thin dorsoplantarly (thick).
Dynatoaetus gaffae is only matched in size in the Australasian region by the extinct New Zealand eagle Hieraaetus moorei, but can be distinguished from the latter via the following features (Hieraaetus state in brackets): the sternum has prominent processus labrum internum present (absent/
very short in H. moorei); in the humerus, the incisura capitis is shallow (deep in H. moorei), the palmar insertion for the m. extensor metacarpi radialis forms a distinct line (circle-shaped in H. moorei), the ventral margin of the fossa forms a curved line parallel to the shaft margin (straight in H. moorei), the distance between the ventral margin of the fossa brachialis and the ventral shaft margin is between 1/3
and 1/4 shaft width (less than 1/4 shaft width in H. moorei), the distance between the tip of the condylus dorsalis and the margin of the tuberculum supracondylare ventrale is equal to the distance between the condylus dorsalis and the lateral margin of the face between the tuberculum upracondylare dorsale and the epicondylus dorsalis (greater width in H. moorei), the interior margin of the tuberculum supracondylare ventrale is oriented at least 45–50° across the shaft (oriented parallel to the shaft in H. moorei); in the ulna, the tuberculum carpale is weakly projecting cranially (moderate projection into a distinct peak); in the tarsometatarsus, the foramen vasculare proximale medialis is located lateral to the crista medialis hypotarsi (located medial to the crista) and is positioned adjacent to the base of the crista (positioned proximal to the base of the crista), the tuberositas m. tibialis cranialis is directly distal to the foramina vascularia proximalia on the dorsal facies (well separated distally), the impressiones retinaculi extensorii form two prominent ridges with a deepened depression between them (ridges absent, no deepening), the impressio lig. collateralis lateralis forms a prominent inflation on the lateral facies (flattened scar), and the second and third trochleae have equal distal extent (third trochlea longer distally). Thus, Dynatoaetus gaffae differs substantially from H. moorei.

Comparative descriptions of Dynatoaetus gaffae with living taxa

For these details I refer to the paper (there is a free pdf)

Fred


Fig. 1 Dynatoaetus gaffae SAMA P.59525 neurocranium in dorsal (A), ventral (B), lateral (C), left antero-lateral (D), and caudal (E) view, and mandible fragments (F). CO condylus occipitalis, COD crista otica
dorsalis, FM foramen magnum, LP lamina parasphenoidalis, LPMP tuberculum basilare, PM processus medialis, PrPa processus paroccipitalis, PrPO processus postorbitalis, PrZ processus zygomaticus, SI
interorbital sulcus, SO sulcus n. olfactorius. Lines on D frame tympanic cavity relative to basioccipital plane. Scale bar is 50 mm

 

[jurek]

I am already waiting for cool CG animations of the new addition to the club of coolest prehistoric megafauna.

 

[Melanie]

Might be interesting to speculate whether the large birds Genyornis and Dromornis belong to its prey similar as the moa was the main prey of the Haast's eagle.

 

[Fred Ruhe]

I am already waiting for cool CG animations of the new addition to the club of coolest prehistoric megafauna.

Might be interesting to speculate whether the large birds Genyornis and Dromornis belong to its prey similar as the moa was the main prey of the Haast's eagle.

I don't like these interprations of extinct animal species, by people that do not not know very muchj about them except some bones, often incomplete. With such a film you will show the public sensation and human interpratations, not the life of extinct animals, only what some artist think they were like, well, I think about a very stupid film as Jurasic park.

Ellen K. Mather, Michael S. Y. Lee, Aaron B. Camens & Trevor H. Worthy suggest the bird was not a scavanger, but a bird that killed its prey, they suggest that on morphological basis. Siggerst, not say as a fact. What will the scriptwriter and the director make of it? Please let dead and extinct animals rest in peace, but studie them.

P. S. That an animal is big does not make it special, it only makes it easier to find.

Fred

 

[Melanie]

The question is whether the claim that this bird was not a scavenger is actually correct. There were two big top predators in Australia during that time: Meiolania and Thylacoleo and I cannot image that Dynatoaetus was able to defy its prey against these two predators.

And Fred please don't compare fiction with scientific documentaries. There is very good material like Monsters we Met or Prehistoric Planet.

 

[Melanie]

Press article on the discovery

Extinct 'Lord of The Rings' eagles had a 10-foot wingspan and probably could have carried a hobbit

Fossils uncovered in Australia belong to a newfound species of extinct eagle that was big enough to pick up hobbit-size prey, like the fictional giant eagles in "The Lord of the Rings."

www.livescience.com