Details

Title

Synsacra of the Eocene Antarctic penguins: new data on spinal maturation and an insight into their role in the control of walking

Journal title

Polish Polar Research

Yearbook

2014

Numer

No 1

Publication authors

Keywords

Antarctica ; Seymour Island ; La Meseta Formation ; Paleogene ; Sphenisciformes ; synsacrum ; spinal cord

Divisions of PAS

Nauki o Ziemi

Coverage

27-39

Abstract

The synsacrum is an important element of the axial skeleton in birds, both volant and flightless. Little is known about the maturation of this complex bone in penguins. In this work, the supposedly ontogenetically youngest known synsacrum of early penguins was described. The analysis of this specimen, collected within the Eocene La Meseta Formation of Seymour (Marambio) Island, Antarctic Peninsula, revealed that this bird had attained at least the fledging stage of growth. Studies of three mature synsacra recovered from the same formation focused on the synsacral canals and, using indirect reasoning, their contents. These analyses revealed that the lumbosacral intumescence of the spinal cord and its extensions, the transverse canals, had been developed roughly like those in extant penguins (and also swifts and cormorants). The neural spine extensions (a non−nervous tissue) tracing the transverse grooves of the dorsal wall of the synsacral canal are currently considered as involved in the control of walking. The presented data suggest that such a sense organ gained its current penguin configuration by the late Eocene.

Publisher

Polish Academy of Sciences ; Committee on Polar Research

Date

2014

Type

Artykuły / Articles

Identifier

ISSN 0138-0338 ; eISSN 2081-8262

DOI

10.2478/popore−2014−0005

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