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A skeletal reconstruction of Archaeopteryx

100%

Elzanowski A., Pasko L.

Acta Ornithologica

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1999

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tom 34

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nr 2

123-129

A novel, skeletal reconstruction of Archaeopteryx skeleton follows Heilmann's (1926) tradition in being based primarily on osteological evidence and free phylogenetic and functional preconceptions. Although the connection between the sternum and ribs remains unknown, a combination of positional and comparative evidence speaks for the presence of cartilaginous sternal ribs. The reconstructed rib cage is compatible with some levels of the airsac ventilation mechanics. The reconstructed segmental position (relative to the vertebral column) of the shoulder girdle at the level of 11th or 12th vertebra agrees with evidence from both modern birds and theropods. The wing must have been largely folded in the resting position, but the geometry and mechanism of wing folding remain conjectural. In its gait and stance, Archaeopteryx was more similar to the modern birds than to the theropods.

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A new genus and species for the largest specimen of Archaeopteryx

84%

Elzanowski A.

Acta Palaeontologica Polonica

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2001

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tom 46

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nr 4

The Solnhofen (Sixth) specimen of Archaeopteryx is assigned to Wellnhoferia grandis gen. et sp. n. on the basis of qualitative, size-independent autapomorphies. Wellnhoferia differs from Archaeopteryx in a short tail with the estimated number of 16-17 caudals; a nearly symmetric pattern of pedal rays II-IV with metatarsals II and IV of equal length and digit IV substantially shorter than in Archaeopteryx; and the number of four (instead of five) phalanges of pedal digit IV, which most probably results from a phylogenetic reduction rather than individual variation. A combination of large size and details of the pelvic limb suggests a locomotor specialization different from that of Archaeopteryx.

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Scapular orientation in theropods and basal birds, and the origin of flapping flight

84%

Senter P.

Acta Palaeontologica Polonica

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2006

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tom 51

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nr 2

Basal birds such as Archaeopteryx and Confuciusornis are typically portrayed as flapping fliers. However, here I show that shoulder joint orientation in these animals prevented elevation of the humerus above the dorsum, thereby preventing use of the recovery stroke, an important part of flapping flight. In members of the clade Ornithothoraces, which includes extant birds and the extinct avian clade Enantiornithes, the shoulder joint is reoriented to permit elevation of the humerus above the dorsum, permitting flapping flight. Although basal birds may have glided, flapping flight began significantly later in avian evolution than has been thought.

Ograniczanie wyników

2 Acta Palaeontologica Polonica

1 Acta Ornithologica

2 Elzanowski A.

1 Pasko L.

1 Senter P.

1 2006

1 2001

1 1999

A skeletal reconstruction of Archaeopteryx

A new genus and species for the largest specimen of Archaeopteryx

Scapular orientation in theropods and basal birds, and the origin of flapping flight