e-journal

Lungfish Diversity In Romer’s Gap: Reaction To The End-Devonian Extinction

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Romer’s Gap, the interval following the end-Devonian extinction event, has been described as a post-extinction trough for vertebrates. It is a time roughly equivalent to the Tournaisian stage of the early Carboniferous
and has been characterized by a lull in diversity of survivors. Lungfish typified this description. One species was
known from one locality. Recently, a diverse collection of lungfish tooth plates, representing seven new forms, was
recovered from new Tournaisian vertebrate localities in northern Britain. They display a range of previously
unknown morphologies, with tooth shape and wear patterns not seen in other post-Devonian forms. A comparison of
tooth ridge number and tooth ridge angle in lungfishes from the Famennian, Tournaisian and Visean reveals marked differences between late Devonian and early Carboniferous taxa. The most common tooth plate shape in the Famennian
is absent from our sample of Tournaisian taxa. Two completely new shapes have evolved, one with a relatively
low tooth ridge angle, no greater than 40
, in which most of the tooth ridges are essentially parallel, and the other
with a much higher tooth ridge angle of up to 180
where the tooth ridges are highly divergent. This high level of
morphological diversity over a narrow time period suggests that, following the end-Devonian extinction, gaps in ecospace left by the extinction of major groups of fishes were exploited by a previously unrecorded radiation of lungfishes. Whilst taxonomic diversity of lungfishes declined following the end-Devonian extinction, recovery and diversification among tooth-plated forms was rapid, and morphological disparity among these forms subsequently increased. Contrary to previous assumptions, morphological disparity among lungfish did not decline until much later in the Carboniferous.

Key words: Tournaisian, Ballagan Formation, tooth plates,diversity, morphology.

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Informasi Detail

Judul Seri

Palaeontology

No. Panggil

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Penerbit

: John Wiley & Sons, Ltd.., 2016

Deskripsi Fisik

[Palaeontology, Vol. 59, Part 1, 2016, pp. 29–44]

Bahasa

English

ISBN/ISSN

doi: 10.1111/pala.12

Klasifikasi

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Tipe Isi

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Tipe Media

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Tipe Pembawa

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Edisi

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Subjek

BIOLOGI

Info Detail Spesifik

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Pernyataan Tanggungjawab

Wati/Agus

Versi lain/terkait

Lampiran Berkas

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