Post by Infinity Blade on May 15, 2020 0:44:50 GMT 5
New Zealand Goose - Cnemiornis spp.
Reconstruction of Cnemiornis. © @ Ripley Cook.
Temporal range: Late Pleistocene (Otiran) to Holocene (Meghalayan); extinct ~800 years ago[1][2]
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
Class: Reptilia or Clade: 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
Suborder: 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: Neognathae
Clade: Pangalloanserae
Superorder: Galloanserae
Clade: Odontoanserae
Clade: Anserimorphae
Order: Anseriformes
Suborder: Anseres
Superfamily: Anatoidea
Family: Anatidae
Subfamily: Anserinae
Genus: †Cnemiornis
Species: †C. gracilis, †C. calcitrans
The New Zealand goose (Cnemiornis spp.) is an extinct genus of flightless goose that lived in New Zealand during the Late Pleistocene (during the last glaciation) until the Holocene epoch. It is comprised of two species: the North Island goose (C. gracilis) and the South Island goose (C. calcitrans).
Phylogeny:
A cladistic analysis of an enlarged data set, coupled with a sequence of mitochondrial DNA from a fossil goose bone, by Worthy et al. (1997) shows Cnemiornis to not only be within Anatidae proper, but also the sister taxon to Cereopsis (the genus containing Cape Barren goose).[3]
Description and paleobiology:
Both New Zealand geese species were comparatively heavy geese. The North Island and South Island species were estimated to weigh 15 and 18 kg, respectively. This makes them at least three times heavier than modern Canada geese (4.5-5.5 kg) and Cape Barren geese (5 kg), and as large as the adzebills (Aptornis) and smaller moa that also lived on New Zealand.[3] These birds were flightless; some anatomical characteristics that might point towards the flightlessness of these geese include:
1.) a humerus with a very squared proximal end, virtually no sulcus transversus, and a deeper impressio coracobrachialis[1]
2.) a very reduced or even absent pneumatic foramen on the coracoid[1]
3.) a very reduced acromion process[1]
4.) the wings are just markedly reduced altogether[1]
Like Cereopsis, Cnemornis had salt gland impressions on top of its skull, although they were relatively reduced. These allowed the bird the forage in salt-rich areas where no freshwater was available, but were less useful in salt-free grasslands.[3]
Unlike Cereopsis, which uses metacarpal spurs on its wings to fight, Cnemiornis lacked a spur-like metacarpal on its carpometacarpus. The reduction of the size of the wings would have also made them ineffective for combat. Instead, Cnemiornis possessed a pedal digit II ungual that was enlarged, straight, and spur-like. It is believed that in lieu of large wings with spurs, Cnemiornis used these spur-like digit II claws as weapons.[1][3]
Right pedal phalanges of C. calcitrans. Note the straight spur-like ungual of digit II. Screen capture from Worthy et al. (1997).[1]
The beak of Cnemiornis was square-tipped, making it effective for grazing and closely cropping swards. Indeed, both species were only found in places where vegetation included grasslands and shrublands. Their bones are common in glacial-aged (presumably Otiran) deposits where there was only grassland or shrubland. But during the Holocene, most lowland in the North Island was covered by tall forests, restricting the North Island goose’s distribution. It could probably only survive in ectocones on dunes, as well as the forest margins in the eastern regions of low rainfall. South Island geese would have fared better, as the rain-shadow zone of the Southern Alps provided a lot of grassland-shrubland-forest mosaic, particularly in what is now Canterbury and Otago.[3]
The eyes of Cnemiornis were relatively larger than its ancestors’, and would have made it easier to spot predators (e.g. Haast’s eagle).[1]
Extinction:
Cnemiornis went extinct after the arrival of the first Polynesian settlers on New Zealand. Both species have been found in archaeological middens, indicating that they were hunted for food, and would have been hunted into extinction by the Māori.[1][3]
References:
[1] Worthy, T. H., Holdaway, R. N., Sorenson, M. D., & Cooper, A. C. (1997). Description of the first complete skeleton of the extinct New Zealand goose Cnemiornis calcitrans (Aves: Anatidae), and a reassessment of the relationships of Cnemiornis. Journal of Zoology, 243(4), 695-718.
[2] Worthy, T. H., & Grant‐Mackie, J. A. (2003). Late‐Pleistocene avifaunas from Cape Wanbrow, Otago, South Island, New Zealand. Journal of the Royal Society of New Zealand, 33(1), 427-485.
[3] Worthy, T. H., & Holdaway, R. N. (2002). The lost world of the moa: prehistoric life of New Zealand. Indiana University Press.
Reconstruction of Cnemiornis. © @ Ripley Cook.
Temporal range: Late Pleistocene (Otiran) to Holocene (Meghalayan); extinct ~800 years ago[1][2]
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
Class: Reptilia or Clade: 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
Suborder: 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: Neognathae
Clade: Pangalloanserae
Superorder: Galloanserae
Clade: Odontoanserae
Clade: Anserimorphae
Order: Anseriformes
Suborder: Anseres
Superfamily: Anatoidea
Family: Anatidae
Subfamily: Anserinae
Genus: †Cnemiornis
Species: †C. gracilis, †C. calcitrans
The New Zealand goose (Cnemiornis spp.) is an extinct genus of flightless goose that lived in New Zealand during the Late Pleistocene (during the last glaciation) until the Holocene epoch. It is comprised of two species: the North Island goose (C. gracilis) and the South Island goose (C. calcitrans).
Phylogeny:
A cladistic analysis of an enlarged data set, coupled with a sequence of mitochondrial DNA from a fossil goose bone, by Worthy et al. (1997) shows Cnemiornis to not only be within Anatidae proper, but also the sister taxon to Cereopsis (the genus containing Cape Barren goose).[3]
Description and paleobiology:
Both New Zealand geese species were comparatively heavy geese. The North Island and South Island species were estimated to weigh 15 and 18 kg, respectively. This makes them at least three times heavier than modern Canada geese (4.5-5.5 kg) and Cape Barren geese (5 kg), and as large as the adzebills (Aptornis) and smaller moa that also lived on New Zealand.[3] These birds were flightless; some anatomical characteristics that might point towards the flightlessness of these geese include:
1.) a humerus with a very squared proximal end, virtually no sulcus transversus, and a deeper impressio coracobrachialis[1]
2.) a very reduced or even absent pneumatic foramen on the coracoid[1]
3.) a very reduced acromion process[1]
4.) the wings are just markedly reduced altogether[1]
Like Cereopsis, Cnemornis had salt gland impressions on top of its skull, although they were relatively reduced. These allowed the bird the forage in salt-rich areas where no freshwater was available, but were less useful in salt-free grasslands.[3]
Unlike Cereopsis, which uses metacarpal spurs on its wings to fight, Cnemiornis lacked a spur-like metacarpal on its carpometacarpus. The reduction of the size of the wings would have also made them ineffective for combat. Instead, Cnemiornis possessed a pedal digit II ungual that was enlarged, straight, and spur-like. It is believed that in lieu of large wings with spurs, Cnemiornis used these spur-like digit II claws as weapons.[1][3]
Right pedal phalanges of C. calcitrans. Note the straight spur-like ungual of digit II. Screen capture from Worthy et al. (1997).[1]
The beak of Cnemiornis was square-tipped, making it effective for grazing and closely cropping swards. Indeed, both species were only found in places where vegetation included grasslands and shrublands. Their bones are common in glacial-aged (presumably Otiran) deposits where there was only grassland or shrubland. But during the Holocene, most lowland in the North Island was covered by tall forests, restricting the North Island goose’s distribution. It could probably only survive in ectocones on dunes, as well as the forest margins in the eastern regions of low rainfall. South Island geese would have fared better, as the rain-shadow zone of the Southern Alps provided a lot of grassland-shrubland-forest mosaic, particularly in what is now Canterbury and Otago.[3]
The eyes of Cnemiornis were relatively larger than its ancestors’, and would have made it easier to spot predators (e.g. Haast’s eagle).[1]
Extinction:
Cnemiornis went extinct after the arrival of the first Polynesian settlers on New Zealand. Both species have been found in archaeological middens, indicating that they were hunted for food, and would have been hunted into extinction by the Māori.[1][3]
References:
[1] Worthy, T. H., Holdaway, R. N., Sorenson, M. D., & Cooper, A. C. (1997). Description of the first complete skeleton of the extinct New Zealand goose Cnemiornis calcitrans (Aves: Anatidae), and a reassessment of the relationships of Cnemiornis. Journal of Zoology, 243(4), 695-718.
[2] Worthy, T. H., & Grant‐Mackie, J. A. (2003). Late‐Pleistocene avifaunas from Cape Wanbrow, Otago, South Island, New Zealand. Journal of the Royal Society of New Zealand, 33(1), 427-485.
[3] Worthy, T. H., & Holdaway, R. N. (2002). The lost world of the moa: prehistoric life of New Zealand. Indiana University Press.
