Post by Infinity Blade on Jul 5, 2022 23:11:51 GMT 5
Emuary – Emuarius spp.
Life reconstruction of Emuarius gidju. © @ Alex Lovegrove->
Temporal range: late Paleogene to early Neogene; late Oligocene to middle Miocene (~24-15 Ma)[1][2][3]
Scientific classification:
Life
Domain: Eukaryota
(unranked): Unikonta
(unranked): Opisthokonta
(unranked): Holozoa
(unranked): Filozoa
Kingdom: Animalia
Subkingdom: Eumetazoa
(unranked): Bilateria
Clade: Nephrozoa
Superphylum: Deuterostomia
Phylum: Chordata
Clade: Olfactores
Clade: Craniata
Subphylum: Vertebrata
Infraphylum: Gnathostomata
Clade: Eugnathostomata
Clade: Teleostomi
Superclass: Tetrapoda
Clade: Reptiliomorpha
Clade: Amniota
Clade: Reptilia or Sauropsida
Clade: Eureptilia
Clade: Romeriida
Clade: Diapsida
Clade: Neodiapsida
Clade: Archelosauria
Clade: Archosauromorpha
Clade: Archosauriformes
Clade: Crurotarsi
Clade: Archosauria
Clade: Avemetatarsalia
Clade: Ornithodira
Clade: Dinosauromorpha
Clade: Dinosauriformes
Clade: Dinosauria
Order: Saurischia
Clade: Eusaurischia
Clade: Theropoda
Clade: Neotheropoda
Clade: Averostra
Clade: Tetanurae
Clade: Orionides
Clade: Avetheropoda
Clade: Coelurosauria
Clade: Tyrannoraptora
Clade: Maniraptoriformes
Clade: Maniraptora
Clade: Pennaraptora
Clade: Paraves
Clade: Eumaniraptora
Clade: Averaptora
Clade: Avialae
Clade: Euavialae
Clade: Avebrevicauda
Clade: Pygostylia
Clade: Ornithothoraces
Clade: Euornithes
Clade: Orithuromorpha
Clade: Ornithurae
Clade: Neornithes
Infraclass: Palaeognathae
Order: Casuariiformes
Family: Casuariidae
Genus: †Emuarius
Species: †E. gidju
†E. guljaruba
Emuarius, known informally as the “emuary”, is an extinct genus of casuariid ratite that lived in Australia during the late Oligocene and middle Miocene.[1][2][3] There are two valid species, E. gidju and E. guljaruba.[1][2]
Classification:
Emuarius is a portmanteau of “emu” and “Casuarius” as a reference to this genus’ intermediate position between these two birds.[2] Colloquially, it is also called an “emuary”[4], another obvious portmanteau of “emu” and “cassowary”. Although originally classified as a species of the genus Dromaius[1], Walter E. Boles reclassified the type species as part of its own genus, Emuarius.[3]
E. gidju was smaller and more gracile than other emus. It had a shorter tarsometatarsus, less reduced outer digits (digits II and IV), and less mediolaterally compressed tarsometatarsus and phalanges than other emus. Characteristics such as these are intermediate between the conditions seen in the emu and cassowary, while others are more similar to one of these genera.[2]
Paleobiology:
The emuary is consistently stated to have a less cursorial morphology in its hindlimb bones compared to the modern emu, such as the ones mentioned above[1][2][3][5], suggesting it was not as fast of a runner. However, its hindlimb bones also appear to be more cursorial than in the more graviportal Casuarius. This is evidenced by the lengthened lower hindlimb bones, lengthened tarsometatarsus relative to the tibiotarsus, and more reduced digit II.[2][3] Thus, it is believed that Emuarius marks a point in which casuariids shifted from being generalized cursors to highly cursorial, reflecting a habitat shift from closed forest to more open habitat during the time.[2][3] That said, the supposedly increased cursoriality of Emuarius (relative to Casuarius) is contradicted by the smaller room for muscle attachment in the pelvis of Emuarius compared to Casuarius, let alone that of Dromaius. The relative size of the anterior ilial region in ratites is directly associated with cursorial ability. This suggests Emuarius might have been slower than even the cassowary, let alone the emu.[5]
Interestingly, while the overall foot structure is more emu-like, the foot of Emuarius is more like that of a cassowary than that of any emu. For instance, while the second digit claw was not a long spike like in the cassowary, it was longer than the claw on the third digit. In modern emus, the claw on the third digit is longer than the one on the second.[2] In birds (and theropod dinosaurs in general), the second toe appears to be in the best position to make contact with a victim when the feet are employed for offensive or defensive kicking. This is based on the fact that birds will attack primarily with the second digit on their foot, whether the claw on that digit is a specialized weapon (as in cassowaries and sandhill cranes) or not (as in emus).[6] Given that the digit II claw of Emuarius is longer than the digit III claw, Emuarius’ feet might have been (to an extent) more dedicated as weapons than those of the modern emu, although not nearly as specialized as the feet of the modern cassowary.
The skull of Emuarius lacks any evidence of a casque like in Casuarius.[5] It also had significantly smaller eyes than Dromaius, further supporting less cursorial habits (due to inferior visual acuity) and lifestyle in denser habitats.[5]
References:
[1] Patterson, C., and Rich, P. V. (1987). The fossil history of the emus, Dromaius (Aves: Dromaiinae). Records of the South Australian Museum 21, 85-117.
[2] Boles, W. E. (2001). A new emu (Dromaiinae) from the late Oligocene Etadunna Formation. Emu, 101(4), 317-321.
[3] Boles, W. E. (1992). Revision of Dromaius gidju Patterson and Rich 1987 from Riversleigh, northwestern Queensland, Australia, with a reassessment of its generic position. Natural History Museum of LA County Science Series, 36, 195-208.
[4] australian.museum/learn/australia-over-time/fossils/sites/riversleigh/
[5] Worthy, T. H., Hand, S. J., & Archer, M. (2014). Phylogenetic relationships of the Australian Oligo–Miocene ratite Emuarius gidju Casuariidae. Integrative Zoology, 9(2), 148-166.
[6] Senter, P. (2009). Pedal function in deinonychosaurs (Dinosauria: Theropoda): a comparative study. Bulletin of the Gunma Museum of Natural History, 13, 1-14.
Life reconstruction of Emuarius gidju. © @ Alex Lovegrove->
Temporal range: late Paleogene to early Neogene; late Oligocene to middle Miocene (~24-15 Ma)[1][2][3]
Scientific classification:
Life
Domain: Eukaryota
(unranked): Unikonta
(unranked): Opisthokonta
(unranked): Holozoa
(unranked): Filozoa
Kingdom: Animalia
Subkingdom: Eumetazoa
(unranked): Bilateria
Clade: Nephrozoa
Superphylum: Deuterostomia
Phylum: Chordata
Clade: Olfactores
Clade: Craniata
Subphylum: Vertebrata
Infraphylum: Gnathostomata
Clade: Eugnathostomata
Clade: Teleostomi
Superclass: Tetrapoda
Clade: Reptiliomorpha
Clade: Amniota
Clade: Reptilia or Sauropsida
Clade: Eureptilia
Clade: Romeriida
Clade: Diapsida
Clade: Neodiapsida
Clade: Archelosauria
Clade: Archosauromorpha
Clade: Archosauriformes
Clade: Crurotarsi
Clade: Archosauria
Clade: Avemetatarsalia
Clade: Ornithodira
Clade: Dinosauromorpha
Clade: Dinosauriformes
Clade: Dinosauria
Order: Saurischia
Clade: Eusaurischia
Clade: Theropoda
Clade: Neotheropoda
Clade: Averostra
Clade: Tetanurae
Clade: Orionides
Clade: Avetheropoda
Clade: Coelurosauria
Clade: Tyrannoraptora
Clade: Maniraptoriformes
Clade: Maniraptora
Clade: Pennaraptora
Clade: Paraves
Clade: Eumaniraptora
Clade: Averaptora
Clade: Avialae
Clade: Euavialae
Clade: Avebrevicauda
Clade: Pygostylia
Clade: Ornithothoraces
Clade: Euornithes
Clade: Orithuromorpha
Clade: Ornithurae
Clade: Neornithes
Infraclass: Palaeognathae
Order: Casuariiformes
Family: Casuariidae
Genus: †Emuarius
Species: †E. gidju
†E. guljaruba
Emuarius, known informally as the “emuary”, is an extinct genus of casuariid ratite that lived in Australia during the late Oligocene and middle Miocene.[1][2][3] There are two valid species, E. gidju and E. guljaruba.[1][2]
Classification:
Emuarius is a portmanteau of “emu” and “Casuarius” as a reference to this genus’ intermediate position between these two birds.[2] Colloquially, it is also called an “emuary”[4], another obvious portmanteau of “emu” and “cassowary”. Although originally classified as a species of the genus Dromaius[1], Walter E. Boles reclassified the type species as part of its own genus, Emuarius.[3]
E. gidju was smaller and more gracile than other emus. It had a shorter tarsometatarsus, less reduced outer digits (digits II and IV), and less mediolaterally compressed tarsometatarsus and phalanges than other emus. Characteristics such as these are intermediate between the conditions seen in the emu and cassowary, while others are more similar to one of these genera.[2]
Paleobiology:
The emuary is consistently stated to have a less cursorial morphology in its hindlimb bones compared to the modern emu, such as the ones mentioned above[1][2][3][5], suggesting it was not as fast of a runner. However, its hindlimb bones also appear to be more cursorial than in the more graviportal Casuarius. This is evidenced by the lengthened lower hindlimb bones, lengthened tarsometatarsus relative to the tibiotarsus, and more reduced digit II.[2][3] Thus, it is believed that Emuarius marks a point in which casuariids shifted from being generalized cursors to highly cursorial, reflecting a habitat shift from closed forest to more open habitat during the time.[2][3] That said, the supposedly increased cursoriality of Emuarius (relative to Casuarius) is contradicted by the smaller room for muscle attachment in the pelvis of Emuarius compared to Casuarius, let alone that of Dromaius. The relative size of the anterior ilial region in ratites is directly associated with cursorial ability. This suggests Emuarius might have been slower than even the cassowary, let alone the emu.[5]
Interestingly, while the overall foot structure is more emu-like, the foot of Emuarius is more like that of a cassowary than that of any emu. For instance, while the second digit claw was not a long spike like in the cassowary, it was longer than the claw on the third digit. In modern emus, the claw on the third digit is longer than the one on the second.[2] In birds (and theropod dinosaurs in general), the second toe appears to be in the best position to make contact with a victim when the feet are employed for offensive or defensive kicking. This is based on the fact that birds will attack primarily with the second digit on their foot, whether the claw on that digit is a specialized weapon (as in cassowaries and sandhill cranes) or not (as in emus).[6] Given that the digit II claw of Emuarius is longer than the digit III claw, Emuarius’ feet might have been (to an extent) more dedicated as weapons than those of the modern emu, although not nearly as specialized as the feet of the modern cassowary.
The skull of Emuarius lacks any evidence of a casque like in Casuarius.[5] It also had significantly smaller eyes than Dromaius, further supporting less cursorial habits (due to inferior visual acuity) and lifestyle in denser habitats.[5]
References:
[1] Patterson, C., and Rich, P. V. (1987). The fossil history of the emus, Dromaius (Aves: Dromaiinae). Records of the South Australian Museum 21, 85-117.
[2] Boles, W. E. (2001). A new emu (Dromaiinae) from the late Oligocene Etadunna Formation. Emu, 101(4), 317-321.
[3] Boles, W. E. (1992). Revision of Dromaius gidju Patterson and Rich 1987 from Riversleigh, northwestern Queensland, Australia, with a reassessment of its generic position. Natural History Museum of LA County Science Series, 36, 195-208.
[4] australian.museum/learn/australia-over-time/fossils/sites/riversleigh/
[5] Worthy, T. H., Hand, S. J., & Archer, M. (2014). Phylogenetic relationships of the Australian Oligo–Miocene ratite Emuarius gidju Casuariidae. Integrative Zoology, 9(2), 148-166.
[6] Senter, P. (2009). Pedal function in deinonychosaurs (Dinosauria: Theropoda): a comparative study. Bulletin of the Gunma Museum of Natural History, 13, 1-14.
