Post by Hatzegopteryx on Apr 5, 2014 0:06:14 GMT
Anzu wyliei
Scientific classification
Temporal range: Maastrichtian, Late Cretaceous, 66Ma
Kingdom: Animalia
Phylum: Chordata
Clade: Dinosauria
Clade: Theropoda
Clade: †Oviraptorosauria
Family: †Caenagnathidae
Subfamily: †Caenagnathinae
Genus: †Anzu (Lamanna et al., 2014)
Type species: Anzu wyliei (Lamanna et al., 2014)
Anzu (named for Anzû, a feathered demon in ancient Mesopotamian mythology), is a genus of oviraptorosaurian dinosaurs from the late Cretaceous (66 million years ago) of North Dakota and South Dakota, USA. The type species is Anzu wyliei.
Description
Anzu wyliei is characterized by a toothless beak, a prominent crest, long arms ending in slender relatively straight claws, long powerful legs with slender toes, and a very long tail. In life, the animal was about 3 metres (9.8 ft) to 3.5 metres (11 ft) long and 200 kilograms (440 lb) to 300 kilograms (660 lb) in weight, making it one of the largest known oviraptorosaurs and the largest known from North America.
When Anzu wyliei was described, several autapomorphies of the type specimen, unique derived traits, were established. There is a high crescent-like crest on the skull, formed by the upper branches of the praemaxillae. The occipital condyle is wider than the foramen magnum. The front part of the lower jaw that is fused with its counterpart has a prominent flange on its outer side. The retroarticular process at the rear of the lower jaw is elongated, about as long as the jaw joint surface. The lower end of the radius is divided into two rounded processes. The first phalanx of the second finger has a trough along the lower edge of its inner side. The front side of the astragalus has at the base of its ascending process a tubercle.
An additional four possible autapomorphies were identified in the referred specimens. The main body of the maxilla has no depression around the antorbital fenestra. The nasal branch of the maxilla is elongated and constructed like an inverted L. The branch of the jugal towards the quadratojugal is vertically deep. The same branch is forked at its rear end.
Reconstructed skeleton at the CMNH
History
Several large skeletons from the late Maastrichtian Hell Creek Formation of Montana and South Dakota were initially referred to as "cf. Chirostenotes", though more recent studies concluded that they represent new species. In 1998, Fred Nuss of Nuss Fossils found two fossils in Harding County, South Dakota. These were prepared by Michael Triebold of Triebold Paleontology. One of these, holotype specimen CM 78000, was given the species name Anzu wyliei in March of 2014. The generic name is derived from the Sumerian winged demon Anzû. The specific name, wyliei, honors Wylie J. Tuttle, the grandson of one of the museum's donors.
Another skeleton found by Fred Nuss, CM 78001, was referred, as was fragmentary skeleton MRF 319, and rear lower jaw fragment FMNH PR 2296. These four fossils found at Hell Creek together make up a fairly complete skeleton of Anzu wyliei. Three researchers, Emma Schachner of the University of Utah, Matthew Lamanna of the Carnegie Museum of Natural History and Tyler Lyson of the Smithsonian in Washington realised in 2005 that they each had partial skeletons of the same species and began collaborating to study it, assisted by Hans-Dieter Sues. The main fossils are being held at the Carnegie Museum of Natural History in Pittsburgh.
The type species is notable as the first well-preserved example of a North American oviraptorosaur. According to Hans-Dieter Sues, a paleontologist at the National Museum of Natural History of the Smithsonian Institution in Washington, DC, "for almost a hundred years, the presence of oviraptorosaurs in North America was only known from a few bits of skeleton, and the details of their appearance and biology remained a mystery. With the discovery of A. wyliei, we finally have the fossil evidence to show what this species looked like and how it is related to other dinosaurs." The creature's formidable appearance – "big crests on their skulls, a beak, no teeth, and a very bird-like skeleton" – led to it being jokingly nicknamed the "chicken from hell" in press releases about its initial publication.
Reconstructed head and neck
Phylogeny
Anzu wyliei was placed in the Oviraptorosauria, as a member of the Caenagnathidae. A cladistic analysis showed it was a possible sister species of Caenagnathus collinsi.
It had been expected that oviraptorosaurs would be found in both Asia and North America as the two continents had a land connection at the time, but the discovery of Anzu wyliei indicates that North American oviraptorosaurs were related more closely to each other than to their counterparts in Asia.
Exposures of the Upper Cretaceous Hell Creek and Lance formations in western North America. Localities that have yielded specimens of Anzu wyliei are marked by white stars. Scale bar = 100 km.
Paleobiology
Anzu wyliei was probably an omnivore or herbivore, although the beak is not as heavily constructed as in the Asian Oviraptoridae.
The fossils of Anzu wyliei were found in mudstone rock that had once been part of ancient floodplains. This indicates that the species likely had a significantly different lifestyle from its Asian counterparts, which lived in arid or semi-arid conditions. Its lifestyle, according to Stephen Brusatte of the University of Edinburgh, was that of "a fast-running, ecological generalist that didn't quite fit the usual moulds of meat-eating or plant-eating dinosaur."
While a number of its features were similar to those of modern birds, it was not an avian dinosaur and its line died out in the Cretaceous–Paleogene extinction event 66 million years ago, along with almost all of the rest of the dinosaurs. Its bird-like features are instead an example of convergent evolution. Matthew Lamanna comments that "it would have had a lot of birdy behaviors. When people think of a dinosaur, they think of something like a Tyrannosaurus or a Brontosaurus, and when they think of a bird, they think of something like a sparrow or a chicken. This animal, Anzu wyliei, has a mosaic of features of both of those groups, and so it basically provides a really nice link in the evolutionary chain."
The purpose of Anzu wyliei's large crest is unclear; Sues notes that it "is very large and made of paper-thin bone, so it was not able to take much stress. All oviraptosaurs have this crest but it is certainly the largest in A. wyliei. The most likely function is for display, showing off to members of your own species. The Australian cassowary has a similar crest which is thought to be used to attract mates, so it is possible that A. wyliei could have used its crest in a similar fashion." The fossils showed evidence of injuries, including a healed broken rib and an arthritic toe that was probably the result of a tendon being ripped away from the bone (an avulsion fracture). It is not known whether this indicates that the animals fought each other, or were injured by predators.
Illustrations of selected elements of the two specimens held at Carnegie Museum (CM 78000 and CM 78001). Left: Postcranial skeleton of Anzu wyliei gen. et sp. nov. as preserved in the CM specimens.
(A) Skeletal reconstruction in left lateral view, with illustrated bones in gray and other preserved bones in white (hatching indicates heavily reconstructed portions of the ilia of CM 78001). (B) Anterior dorsal vertebra of CM 78001 in anterior view. Anterior (C) and posteriormost preserved (D) caudal vertebrae of CM 78000 in left lateral view. (E) Right humerus of CM 78000 in anterior view. (F) Manual ungual I of CM 78000 in lateral view. Left pubis (G) and ischium (H) of CM 78001 in lateral view. Right femur (I) and left tibia (J) and astragalocalcaneum (K) of CM 78000 in anterior view. (L) Pedal ungual of CM 78000 in lateral view. Abbreviations: ap, ascending process; atc, ‘accessory trochanteric crest’; cal, calcaneum; cc, cnemial crest; dpc, deltopectoral crest; el, extensor ‘lip’; f, foramen; fh, femoral head; hy, hypapophysis; isp, ischial peduncle; ns, neural spine; op, obturator process; pb, pubic ‘boot’; pf, pneumatic fossa; prz, prezygapophysis; tp, transverse process; tu, tubercle; vg, vascular groove. Scale bars = 50 cm in A; 1 cm in B–L.
Right: Craniomandibular skeleton of Anzu wyliei gen. et sp. nov.
(A) Reconstructed skull and mandible in left lateral view, with preserved bones in gray. (B) Left premaxilla of CM 78001 in lateral view. (C) Left maxilla of CM 78001 in lateral view. (D) Left jugal of CM 78001 in lateral view. (E) Braincase with articulated quadrates and pterygoids of CM 78001 in posterior view. Reconstructed mandible of CM 78000 in left lateral (F) and dorsal (G) views (hatching indicates broken areas, dashed lines indicate restoration). Abbreviations: ang, angular; aof, antorbital fenestra; ap, ascending process; bpt, basipterygoid process; d, dentary; emf, external mandibular fenestra; fm, foramen magnum; lf, lateral flange; lg, lateral groove; lgl, lateral facet of mandibular glenoid; lr, lingual ridge; mgl, medial facet of mandibular glenoid; oc, occipital condyle; pdp, posterodorsal process; pop, paroccipital process; por, postorbital process; pt, pterygoid; pvp, posteroventral process; q, quadrate; qjp, quadratojugal process; r, retroarticular process; sac, surangular–articular–coronoid complex. Scale bars = 10 cm in A; 1 cm in B–G. Authors: Scott Hartman, Matthew C. Lamanna, Hans-Dieter Sues, Emma R. Schachner, Tyler R. Lyson. Source: www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0092022
Publications
New "Chicken From Hell" Dinosaur Discovered: news.nationalgeographic.com/news/2014/03/140319-dinosaurs-feathers-animals-science-new-species/
A New Large-Bodied Oviraptorosaurian Theropod Dinosaur from the Latest Cretaceous of Western North America: www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0092022
Images
Anzu wyliei skull, shown in a reconstruction
FIGURE 5: MRF 319, a partial oviraptorosaurian skeleton referred to Anzu wyliei gen. et sp. nov.
(A) Skeletal reconstruction in left lateral view, with preserved bones in gray and bones represented in other Anzu specimens in white (hatching indicates heavily reconstructed portions of the ilia of CM 78001). Middle-posterior (ninth?) cervical vertebra in (B) anterior, (C) left lateral, and (D) dorsal views. Posterior (11th?) cervical vertebra in (E) anterior, (F) left lateral, and (G) dorsal views. Posterior (12th?) cervical vertebra in (H) anterior, (I) left lateral, and (J) dorsal views. Anteroposteriorly crushed left radius in lateral (K) and anterior (L) views. Mediolaterally crushed left ulna in lateral (M) and anterior (N) views. (O) Partial left scapulocoracoid in lateral view. Dorsal rib in anterior (P) and posterior (Q) views. Abbreviations: acr, acromial process; cr, cervical rib; dip, distal processes; pat, pathology; pf, pneumatic fossa. Scale bars = 50 cm in A; 1 cm in B–Q.
FIGURE 6: Strict consensus trees resulting from successive trials of phylogenetic analysis.
Numbers adjacent to each node are Bremer support values; named nodes are indicated with black dots. (A) Strict consensus of 2,610 most parsimonious trees of 509 steps recovered by initial analysis of all 41 taxa (38 oviraptorosaurs) included in the matrix. (B) Strict consensus of seven most parsimonious trees of 498 steps resulting from an analysis of 34 taxa (31 oviraptorosaurs), excluding all members of Caenagnathidae (as recovered by the initial trial) for which definitive mandibular material has not yet been discovered.
FIGURE 7: Calibrated phylogeny of oviraptorosaurian theropods showing hypothesized position of Anzu wyliei gen. et sp. nov.
Depicted topology is the strict consensus of seven most parsimonious trees of 498 steps resulting from an analysis of 34 taxa (31 oviraptorosaurs) scored for 230 morphological characters (Figure 6B). Numbers adjacent to each node are Bremer support values; named nodes are indicated with black dots. Thick black bars indicate stratigraphic ranges of each taxon; small crossbars at ends of some bars indicate taxa that are especially poorly stratigraphically constrained (e.g., most Asian Late Cretaceous forms). Time scale follows [98]. Sources for stratigraphic ranges of included taxa are provided in Table S9 in File S1
Scientific classification
Temporal range: Maastrichtian, Late Cretaceous, 66Ma
Kingdom: Animalia
Phylum: Chordata
Clade: Dinosauria
Clade: Theropoda
Clade: †Oviraptorosauria
Family: †Caenagnathidae
Subfamily: †Caenagnathinae
Genus: †Anzu (Lamanna et al., 2014)
Type species: Anzu wyliei (Lamanna et al., 2014)
Anzu (named for Anzû, a feathered demon in ancient Mesopotamian mythology), is a genus of oviraptorosaurian dinosaurs from the late Cretaceous (66 million years ago) of North Dakota and South Dakota, USA. The type species is Anzu wyliei.
Description
Anzu wyliei is characterized by a toothless beak, a prominent crest, long arms ending in slender relatively straight claws, long powerful legs with slender toes, and a very long tail. In life, the animal was about 3 metres (9.8 ft) to 3.5 metres (11 ft) long and 200 kilograms (440 lb) to 300 kilograms (660 lb) in weight, making it one of the largest known oviraptorosaurs and the largest known from North America.
When Anzu wyliei was described, several autapomorphies of the type specimen, unique derived traits, were established. There is a high crescent-like crest on the skull, formed by the upper branches of the praemaxillae. The occipital condyle is wider than the foramen magnum. The front part of the lower jaw that is fused with its counterpart has a prominent flange on its outer side. The retroarticular process at the rear of the lower jaw is elongated, about as long as the jaw joint surface. The lower end of the radius is divided into two rounded processes. The first phalanx of the second finger has a trough along the lower edge of its inner side. The front side of the astragalus has at the base of its ascending process a tubercle.
An additional four possible autapomorphies were identified in the referred specimens. The main body of the maxilla has no depression around the antorbital fenestra. The nasal branch of the maxilla is elongated and constructed like an inverted L. The branch of the jugal towards the quadratojugal is vertically deep. The same branch is forked at its rear end.
Reconstructed skeleton at the CMNH
History
Several large skeletons from the late Maastrichtian Hell Creek Formation of Montana and South Dakota were initially referred to as "cf. Chirostenotes", though more recent studies concluded that they represent new species. In 1998, Fred Nuss of Nuss Fossils found two fossils in Harding County, South Dakota. These were prepared by Michael Triebold of Triebold Paleontology. One of these, holotype specimen CM 78000, was given the species name Anzu wyliei in March of 2014. The generic name is derived from the Sumerian winged demon Anzû. The specific name, wyliei, honors Wylie J. Tuttle, the grandson of one of the museum's donors.
Another skeleton found by Fred Nuss, CM 78001, was referred, as was fragmentary skeleton MRF 319, and rear lower jaw fragment FMNH PR 2296. These four fossils found at Hell Creek together make up a fairly complete skeleton of Anzu wyliei. Three researchers, Emma Schachner of the University of Utah, Matthew Lamanna of the Carnegie Museum of Natural History and Tyler Lyson of the Smithsonian in Washington realised in 2005 that they each had partial skeletons of the same species and began collaborating to study it, assisted by Hans-Dieter Sues. The main fossils are being held at the Carnegie Museum of Natural History in Pittsburgh.
The type species is notable as the first well-preserved example of a North American oviraptorosaur. According to Hans-Dieter Sues, a paleontologist at the National Museum of Natural History of the Smithsonian Institution in Washington, DC, "for almost a hundred years, the presence of oviraptorosaurs in North America was only known from a few bits of skeleton, and the details of their appearance and biology remained a mystery. With the discovery of A. wyliei, we finally have the fossil evidence to show what this species looked like and how it is related to other dinosaurs." The creature's formidable appearance – "big crests on their skulls, a beak, no teeth, and a very bird-like skeleton" – led to it being jokingly nicknamed the "chicken from hell" in press releases about its initial publication.
Reconstructed head and neck
Phylogeny
Anzu wyliei was placed in the Oviraptorosauria, as a member of the Caenagnathidae. A cladistic analysis showed it was a possible sister species of Caenagnathus collinsi.
It had been expected that oviraptorosaurs would be found in both Asia and North America as the two continents had a land connection at the time, but the discovery of Anzu wyliei indicates that North American oviraptorosaurs were related more closely to each other than to their counterparts in Asia.
Exposures of the Upper Cretaceous Hell Creek and Lance formations in western North America. Localities that have yielded specimens of Anzu wyliei are marked by white stars. Scale bar = 100 km.
Paleobiology
Anzu wyliei was probably an omnivore or herbivore, although the beak is not as heavily constructed as in the Asian Oviraptoridae.
The fossils of Anzu wyliei were found in mudstone rock that had once been part of ancient floodplains. This indicates that the species likely had a significantly different lifestyle from its Asian counterparts, which lived in arid or semi-arid conditions. Its lifestyle, according to Stephen Brusatte of the University of Edinburgh, was that of "a fast-running, ecological generalist that didn't quite fit the usual moulds of meat-eating or plant-eating dinosaur."
While a number of its features were similar to those of modern birds, it was not an avian dinosaur and its line died out in the Cretaceous–Paleogene extinction event 66 million years ago, along with almost all of the rest of the dinosaurs. Its bird-like features are instead an example of convergent evolution. Matthew Lamanna comments that "it would have had a lot of birdy behaviors. When people think of a dinosaur, they think of something like a Tyrannosaurus or a Brontosaurus, and when they think of a bird, they think of something like a sparrow or a chicken. This animal, Anzu wyliei, has a mosaic of features of both of those groups, and so it basically provides a really nice link in the evolutionary chain."
The purpose of Anzu wyliei's large crest is unclear; Sues notes that it "is very large and made of paper-thin bone, so it was not able to take much stress. All oviraptosaurs have this crest but it is certainly the largest in A. wyliei. The most likely function is for display, showing off to members of your own species. The Australian cassowary has a similar crest which is thought to be used to attract mates, so it is possible that A. wyliei could have used its crest in a similar fashion." The fossils showed evidence of injuries, including a healed broken rib and an arthritic toe that was probably the result of a tendon being ripped away from the bone (an avulsion fracture). It is not known whether this indicates that the animals fought each other, or were injured by predators.
Illustrations of selected elements of the two specimens held at Carnegie Museum (CM 78000 and CM 78001). Left: Postcranial skeleton of Anzu wyliei gen. et sp. nov. as preserved in the CM specimens.
(A) Skeletal reconstruction in left lateral view, with illustrated bones in gray and other preserved bones in white (hatching indicates heavily reconstructed portions of the ilia of CM 78001). (B) Anterior dorsal vertebra of CM 78001 in anterior view. Anterior (C) and posteriormost preserved (D) caudal vertebrae of CM 78000 in left lateral view. (E) Right humerus of CM 78000 in anterior view. (F) Manual ungual I of CM 78000 in lateral view. Left pubis (G) and ischium (H) of CM 78001 in lateral view. Right femur (I) and left tibia (J) and astragalocalcaneum (K) of CM 78000 in anterior view. (L) Pedal ungual of CM 78000 in lateral view. Abbreviations: ap, ascending process; atc, ‘accessory trochanteric crest’; cal, calcaneum; cc, cnemial crest; dpc, deltopectoral crest; el, extensor ‘lip’; f, foramen; fh, femoral head; hy, hypapophysis; isp, ischial peduncle; ns, neural spine; op, obturator process; pb, pubic ‘boot’; pf, pneumatic fossa; prz, prezygapophysis; tp, transverse process; tu, tubercle; vg, vascular groove. Scale bars = 50 cm in A; 1 cm in B–L.
Right: Craniomandibular skeleton of Anzu wyliei gen. et sp. nov.
(A) Reconstructed skull and mandible in left lateral view, with preserved bones in gray. (B) Left premaxilla of CM 78001 in lateral view. (C) Left maxilla of CM 78001 in lateral view. (D) Left jugal of CM 78001 in lateral view. (E) Braincase with articulated quadrates and pterygoids of CM 78001 in posterior view. Reconstructed mandible of CM 78000 in left lateral (F) and dorsal (G) views (hatching indicates broken areas, dashed lines indicate restoration). Abbreviations: ang, angular; aof, antorbital fenestra; ap, ascending process; bpt, basipterygoid process; d, dentary; emf, external mandibular fenestra; fm, foramen magnum; lf, lateral flange; lg, lateral groove; lgl, lateral facet of mandibular glenoid; lr, lingual ridge; mgl, medial facet of mandibular glenoid; oc, occipital condyle; pdp, posterodorsal process; pop, paroccipital process; por, postorbital process; pt, pterygoid; pvp, posteroventral process; q, quadrate; qjp, quadratojugal process; r, retroarticular process; sac, surangular–articular–coronoid complex. Scale bars = 10 cm in A; 1 cm in B–G. Authors: Scott Hartman, Matthew C. Lamanna, Hans-Dieter Sues, Emma R. Schachner, Tyler R. Lyson. Source: www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0092022
Publications
New "Chicken From Hell" Dinosaur Discovered: news.nationalgeographic.com/news/2014/03/140319-dinosaurs-feathers-animals-science-new-species/
A New Large-Bodied Oviraptorosaurian Theropod Dinosaur from the Latest Cretaceous of Western North America: www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0092022
Images
Anzu wyliei skull, shown in a reconstruction
FIGURE 5: MRF 319, a partial oviraptorosaurian skeleton referred to Anzu wyliei gen. et sp. nov.
(A) Skeletal reconstruction in left lateral view, with preserved bones in gray and bones represented in other Anzu specimens in white (hatching indicates heavily reconstructed portions of the ilia of CM 78001). Middle-posterior (ninth?) cervical vertebra in (B) anterior, (C) left lateral, and (D) dorsal views. Posterior (11th?) cervical vertebra in (E) anterior, (F) left lateral, and (G) dorsal views. Posterior (12th?) cervical vertebra in (H) anterior, (I) left lateral, and (J) dorsal views. Anteroposteriorly crushed left radius in lateral (K) and anterior (L) views. Mediolaterally crushed left ulna in lateral (M) and anterior (N) views. (O) Partial left scapulocoracoid in lateral view. Dorsal rib in anterior (P) and posterior (Q) views. Abbreviations: acr, acromial process; cr, cervical rib; dip, distal processes; pat, pathology; pf, pneumatic fossa. Scale bars = 50 cm in A; 1 cm in B–Q.
FIGURE 6: Strict consensus trees resulting from successive trials of phylogenetic analysis.
Numbers adjacent to each node are Bremer support values; named nodes are indicated with black dots. (A) Strict consensus of 2,610 most parsimonious trees of 509 steps recovered by initial analysis of all 41 taxa (38 oviraptorosaurs) included in the matrix. (B) Strict consensus of seven most parsimonious trees of 498 steps resulting from an analysis of 34 taxa (31 oviraptorosaurs), excluding all members of Caenagnathidae (as recovered by the initial trial) for which definitive mandibular material has not yet been discovered.
FIGURE 7: Calibrated phylogeny of oviraptorosaurian theropods showing hypothesized position of Anzu wyliei gen. et sp. nov.
Depicted topology is the strict consensus of seven most parsimonious trees of 498 steps resulting from an analysis of 34 taxa (31 oviraptorosaurs) scored for 230 morphological characters (Figure 6B). Numbers adjacent to each node are Bremer support values; named nodes are indicated with black dots. Thick black bars indicate stratigraphic ranges of each taxon; small crossbars at ends of some bars indicate taxa that are especially poorly stratigraphically constrained (e.g., most Asian Late Cretaceous forms). Time scale follows [98]. Sources for stratigraphic ranges of included taxa are provided in Table S9 in File S1