[D] Ambiortus dementjevi [~/~]
Describer
Kurochkin, 1982
Time
Cretaceous Early Hauteravian Barremian Aptian
Classification
Saurischia Theropoda Tetanurae Coelurosauria Maniraptora Avialae Ornithothoraces Ornithurae
Fossilsite
Unduruh Formation, Khurilt Ulaan Bulag locality, Central Mongolian Altai Mountains, Bayankhongor, Mongolia
Info
Ambiortus dementjevi (Kurochkin, 1982) > ?Holbotia ponomarenkoi (Kurochkin, 1982)
Holotype: PIN 3790-271+, 3790-271-,and 3790-272, portion of the articulated left shoulder girdle, the left forelimb, and cervical and thoarcic vertebrae.
Procoracoid process wide and long; scupularacromion long and dorsoventrally compressed; deep groove along lateral side of the scapula; scapular balde narrow; short, fossa like groove cranial to the tubervle on the projecting ventral edge of the proximal end of the humerus; undivided capital groove in the proximal end of the humerus; metacarpals fused at the proximal end; intermediate phalanx of the major digit dorsoventrally compressed.
Ambiortus represents the earliest known stage in the evolution of neornithine birds. It indicates that early palaeognaths were keeled birds and good fliers. Comparison with the Lithornithiformes and the Ichthyyornithiformes does not support the opinion of Martin (1991) and Elzanowski (1995) regarding the close relationships of Ambiortus to the Ichthyornithiformes. (Kurochkin, 2000)
Kurochkin, 1982
Time
Cretaceous Early Hauteravian Barremian Aptian
Classification
Saurischia Theropoda Tetanurae Coelurosauria Maniraptora Avialae Ornithothoraces Ornithurae
Fossilsite
Unduruh Formation, Khurilt Ulaan Bulag locality, Central Mongolian Altai Mountains, Bayankhongor, Mongolia
Info
Ambiortus dementjevi (Kurochkin, 1982) > ?Holbotia ponomarenkoi (Kurochkin, 1982)
Holotype: PIN 3790-271+, 3790-271-,and 3790-272, portion of the articulated left shoulder girdle, the left forelimb, and cervical and thoarcic vertebrae.
Procoracoid process wide and long; scupularacromion long and dorsoventrally compressed; deep groove along lateral side of the scapula; scapular balde narrow; short, fossa like groove cranial to the tubervle on the projecting ventral edge of the proximal end of the humerus; undivided capital groove in the proximal end of the humerus; metacarpals fused at the proximal end; intermediate phalanx of the major digit dorsoventrally compressed.
Ambiortus represents the earliest known stage in the evolution of neornithine birds. It indicates that early palaeognaths were keeled birds and good fliers. Comparison with the Lithornithiformes and the Ichthyyornithiformes does not support the opinion of Martin (1991) and Elzanowski (1995) regarding the close relationships of Ambiortus to the Ichthyornithiformes. (Kurochkin, 2000)