At the root of the early penguin neck: a study of the only two cervicodorsal spines recovered from the Eocene of Antarctica

The spinal column of early Antarctic penguins is poorly known, mainly due to the scarcity of articulated vertebrae in the fossil record. One of the most interesting segments of this part of the skeleton is the transitional series located at the root of the neck. Here, two such cervicodorsal series,...

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Main Author: Piotr Jadwiszczak
Format: Article
Language:English
Published: Norwegian Polar Institute 2014-11-01
Series:Polar Research
Subjects:
Online Access:http://www.polarresearch.net/index.php/polar/article/download/23861/pdf_1
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author Piotr Jadwiszczak
author_facet Piotr Jadwiszczak
author_sort Piotr Jadwiszczak
collection DOAJ
description The spinal column of early Antarctic penguins is poorly known, mainly due to the scarcity of articulated vertebrae in the fossil record. One of the most interesting segments of this part of the skeleton is the transitional series located at the root of the neck. Here, two such cervicodorsal series, comprising reinterpreted known material and a new specimen from the Eocene of Seymour Island (Antarctic Peninsula), were investigated and contrasted with those of modern penguins and some fossil bones. The new specimen is smaller than the counterpart elements in recent king penguins, whereas the second series belonged to a large-bodied penguin from the genus Palaeeudyptes. It had been assigned by earlier researchers to P. gunnari (a species of “giant” penguins) and a Bayesian analysis—a Bayes factor approach based on size of an associated tarsometatarsus—strongly supported such an assignment. Morphological and functional studies revealed that mobility within the aforementioned segment probably did not differ substantially between extant and studied fossil penguins. There were, however, intriguing morphological differences between the smaller fossil specimen and the comparative material related to the condition of the lateral excavation in the first cervicodorsal vertebra and the extremely small size of the intervertebral foramen located just prior to the first “true” thoracic vertebra. The former feature could have resulted from discrepancy in severity of external pneumatization. Both fossils provided valuable insights into the morphology and functioning of the axial skeleton in early penguins.
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spelling doaj.art-0607742ca0634857992d64d569b765712022-12-21T22:11:00ZengNorwegian Polar InstitutePolar Research1751-83692014-11-013301910.3402/polar.v33.2386123861At the root of the early penguin neck: a study of the only two cervicodorsal spines recovered from the Eocene of AntarcticaPiotr Jadwiszczak0Institute of Biology, University of Bialystok, Swierkowa 20B, PL-15-950, Bialystok, PolandThe spinal column of early Antarctic penguins is poorly known, mainly due to the scarcity of articulated vertebrae in the fossil record. One of the most interesting segments of this part of the skeleton is the transitional series located at the root of the neck. Here, two such cervicodorsal series, comprising reinterpreted known material and a new specimen from the Eocene of Seymour Island (Antarctic Peninsula), were investigated and contrasted with those of modern penguins and some fossil bones. The new specimen is smaller than the counterpart elements in recent king penguins, whereas the second series belonged to a large-bodied penguin from the genus Palaeeudyptes. It had been assigned by earlier researchers to P. gunnari (a species of “giant” penguins) and a Bayesian analysis—a Bayes factor approach based on size of an associated tarsometatarsus—strongly supported such an assignment. Morphological and functional studies revealed that mobility within the aforementioned segment probably did not differ substantially between extant and studied fossil penguins. There were, however, intriguing morphological differences between the smaller fossil specimen and the comparative material related to the condition of the lateral excavation in the first cervicodorsal vertebra and the extremely small size of the intervertebral foramen located just prior to the first “true” thoracic vertebra. The former feature could have resulted from discrepancy in severity of external pneumatization. Both fossils provided valuable insights into the morphology and functioning of the axial skeleton in early penguins.http://www.polarresearch.net/index.php/polar/article/download/23861/pdf_1Antarctic PeninsulaLa Meseta FormationPalaeogeneearly Sphenisciformescervicodorsal vertebrae
spellingShingle Piotr Jadwiszczak
At the root of the early penguin neck: a study of the only two cervicodorsal spines recovered from the Eocene of Antarctica
Polar Research
Antarctic Peninsula
La Meseta Formation
Palaeogene
early Sphenisciformes
cervicodorsal vertebrae
title At the root of the early penguin neck: a study of the only two cervicodorsal spines recovered from the Eocene of Antarctica
title_full At the root of the early penguin neck: a study of the only two cervicodorsal spines recovered from the Eocene of Antarctica
title_fullStr At the root of the early penguin neck: a study of the only two cervicodorsal spines recovered from the Eocene of Antarctica
title_full_unstemmed At the root of the early penguin neck: a study of the only two cervicodorsal spines recovered from the Eocene of Antarctica
title_short At the root of the early penguin neck: a study of the only two cervicodorsal spines recovered from the Eocene of Antarctica
title_sort at the root of the early penguin neck a study of the only two cervicodorsal spines recovered from the eocene of antarctica
topic Antarctic Peninsula
La Meseta Formation
Palaeogene
early Sphenisciformes
cervicodorsal vertebrae
url http://www.polarresearch.net/index.php/polar/article/download/23861/pdf_1
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