Post by Eaglehawk on Jul 26, 2019 5:53:53 GMT
Conflicto antarcticus
Temporal range: Early Paleocene
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Aves
Order: Anseriformes
Genus: †Conflicto Claudia P. Tambussi et al. 2019
Species: †Conflicto antarcticus Claudia P. Tambussi et al. 2019
Conflicto antarcticus is a species of stem anseriform whose fossils were found in the early Paleocene López de Bertodano Formation of Antarctica, the only species of its genus. It is characterized by it slender body and long legs, yet possesses a duck-like bill which indicates the form of beak evolved early in Anseriformes.
Skeletal anatomy of Conflicto antarcticus gen. et sp. nov. MLP 07-III-1-1. Bones coloured in grey are missing. Some of the bones have been mirrored (e.g. os quadratum, os coracoideum) or restored based on both homologous bones (e.g. humerus) Scale bar: 5 cm.
Description
Conflicto is known from a single partially complete specimen described in January 2019. It had long legs compared to its body, contrasting what is seen in modern ducks. It is estimated to be around 36 centimetres (14 in) in length, and had a long head relative to body size. Its beak had a similar structure to that of ducks and geese, but was not as wide. The rostrum possessed narial openings wider than that of modern Anseriformes. Its neck was about half its body length, possessing (estimated) 15 long vertebrae.
Classification
Conflicto was a likely a stem anseriform, equally related to the current extant clades. The genus Anatalavis is hypothesized to be less related to the magpie goose as previously thought, but placed as a sister clade to Conflicto, though this isn't conclusive. The phylogenetic classification remains uncertain, but is more likely to be stem-waterfowl rather than crown-waterfowl, separated from modern anseriform lineages.
Journal Reference:
Claudia P. Tambussi, Federico J. Degrange, Ricardo S. De Mendoza, Emilia Sferco and Sergrio Santillana. 2019. A Stem Anseriform from the early Palaeocene of Antarctica provides New Key Evidence in the Early Evolution of Waterfowl. Zoological Journal of the Linnean Society. 186(3); 673–700. DOI: 10.1093/zoolinnean/zly085
Abstract
A new Anseriformes, Conflicto antarcticus gen. et sp. nov., represented by associated bones of a single individual, from the early Palaeocene of Antarctica is described. The new taxon is unlike any other known member of the order. Conflicto antarcticus is a medium-sized (2 kg) stem anseriform. The forelimb and pectoral girdle bones suggest that it was a flying bird, and the bones of the hindlimb show that it had elongated legs. The os quadratum represents a unique combination of features; some are similar to the features of the ancestral quadrate for galloanserines and some are similar to Anseriformes, but features such as the presence of three foramina are exclusive among Neornithes. The incisura or foramen nervi suracoracoidei is absent in C. antarcticus, as in most anatids and all Galliformes. Phylogenetic analysis shows that C. antarcticus + Anatalavis oxfordi is the most basal stem Anseriformes clade. This implies that the duck-type beak must have developed at an early stage of anseriform evolution. Conflicto antarcticus represents one (and possibly the most) substantial record of a non-marine Palaeocene bird from the Southern Hemisphere and supports the hypothesis that Neognathae had already diversified in the earliest Palaeocene.
The skull of Conflicto antarcticus gen. et sp. nov. A, left lateral view. B, right lateral view. The arrows point at the bulges of the os frontale.
Abbreviations: cnt, crista nuchalis transversa; fal, facies articularis lacrimalis; fg, fossae glandularum; fnII, nerve II exit foramen; fnV2-3, nerve V2–3 exit foramen; foc, fonticuli orbitocraniales; foi, fonticulus interorbitalis; fst, fossa subtemporalis; ft, fossa temporalis; na, nares; pbt, processus basipterygoideus; pc, prominentia cerebellaris; pco, processus coronoideus; plm, processus lateralis mandibulae; pp, processus paroccipitalis; ppo, processus postorbitalis; pr, processus retroarticularis; psn, pila supranasalis; rp, rostrum parasphenoidale; ta, tuba auditiva. Scale bar: 1 cm.
academic.oup.com/zoolinnean/article-abstract/186/3/673/5281199?redirectedFrom=fulltext
Temporal range: Early Paleocene
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Aves
Order: Anseriformes
Genus: †Conflicto Claudia P. Tambussi et al. 2019
Species: †Conflicto antarcticus Claudia P. Tambussi et al. 2019
Conflicto antarcticus is a species of stem anseriform whose fossils were found in the early Paleocene López de Bertodano Formation of Antarctica, the only species of its genus. It is characterized by it slender body and long legs, yet possesses a duck-like bill which indicates the form of beak evolved early in Anseriformes.
Skeletal anatomy of Conflicto antarcticus gen. et sp. nov. MLP 07-III-1-1. Bones coloured in grey are missing. Some of the bones have been mirrored (e.g. os quadratum, os coracoideum) or restored based on both homologous bones (e.g. humerus) Scale bar: 5 cm.
Description
Conflicto is known from a single partially complete specimen described in January 2019. It had long legs compared to its body, contrasting what is seen in modern ducks. It is estimated to be around 36 centimetres (14 in) in length, and had a long head relative to body size. Its beak had a similar structure to that of ducks and geese, but was not as wide. The rostrum possessed narial openings wider than that of modern Anseriformes. Its neck was about half its body length, possessing (estimated) 15 long vertebrae.
Classification
Conflicto was a likely a stem anseriform, equally related to the current extant clades. The genus Anatalavis is hypothesized to be less related to the magpie goose as previously thought, but placed as a sister clade to Conflicto, though this isn't conclusive. The phylogenetic classification remains uncertain, but is more likely to be stem-waterfowl rather than crown-waterfowl, separated from modern anseriform lineages.
Journal Reference:
Claudia P. Tambussi, Federico J. Degrange, Ricardo S. De Mendoza, Emilia Sferco and Sergrio Santillana. 2019. A Stem Anseriform from the early Palaeocene of Antarctica provides New Key Evidence in the Early Evolution of Waterfowl. Zoological Journal of the Linnean Society. 186(3); 673–700. DOI: 10.1093/zoolinnean/zly085
Abstract
A new Anseriformes, Conflicto antarcticus gen. et sp. nov., represented by associated bones of a single individual, from the early Palaeocene of Antarctica is described. The new taxon is unlike any other known member of the order. Conflicto antarcticus is a medium-sized (2 kg) stem anseriform. The forelimb and pectoral girdle bones suggest that it was a flying bird, and the bones of the hindlimb show that it had elongated legs. The os quadratum represents a unique combination of features; some are similar to the features of the ancestral quadrate for galloanserines and some are similar to Anseriformes, but features such as the presence of three foramina are exclusive among Neornithes. The incisura or foramen nervi suracoracoidei is absent in C. antarcticus, as in most anatids and all Galliformes. Phylogenetic analysis shows that C. antarcticus + Anatalavis oxfordi is the most basal stem Anseriformes clade. This implies that the duck-type beak must have developed at an early stage of anseriform evolution. Conflicto antarcticus represents one (and possibly the most) substantial record of a non-marine Palaeocene bird from the Southern Hemisphere and supports the hypothesis that Neognathae had already diversified in the earliest Palaeocene.
The skull of Conflicto antarcticus gen. et sp. nov. A, left lateral view. B, right lateral view. The arrows point at the bulges of the os frontale.
Abbreviations: cnt, crista nuchalis transversa; fal, facies articularis lacrimalis; fg, fossae glandularum; fnII, nerve II exit foramen; fnV2-3, nerve V2–3 exit foramen; foc, fonticuli orbitocraniales; foi, fonticulus interorbitalis; fst, fossa subtemporalis; ft, fossa temporalis; na, nares; pbt, processus basipterygoideus; pc, prominentia cerebellaris; pco, processus coronoideus; plm, processus lateralis mandibulae; pp, processus paroccipitalis; ppo, processus postorbitalis; pr, processus retroarticularis; psn, pila supranasalis; rp, rostrum parasphenoidale; ta, tuba auditiva. Scale bar: 1 cm.
academic.oup.com/zoolinnean/article-abstract/186/3/673/5281199?redirectedFrom=fulltext