Ontogeny and structure of a new, miniaturised and spiny olenid trilobite from Southern Sweden

Research output: Contribution to journalArticle

Standard

Ontogeny and structure of a new, miniaturised and spiny olenid trilobite from Southern Sweden. / Clarkson, ENK; Ahlberg, Per.

In: Palaeontology, Vol. 45, 2002, p. 1-22.

Research output: Contribution to journalArticle

Harvard

APA

CBE

MLA

Vancouver

Author

RIS

TY - JOUR

T1 - Ontogeny and structure of a new, miniaturised and spiny olenid trilobite from Southern Sweden

AU - Clarkson, ENK

AU - Ahlberg, Per

PY - 2002

Y1 - 2002

N2 - Several hundred specimens of a tiny olenid trilobite, Ctenopyge ceciliae sp. nov., have been found in stinkstone nodules in the upper Cambrian Peltura scarabaeoides Zone in southern Sweden. This exceptionally spinose form is known only from disarticulated specimens, but is quite well preserved, and all growth stages are represented. The early ontogenetic stages are exceptionally small, the protaspis being only half the size of that of the associated Peltura species. There may have been no more than three thoracic segments. Thus the whole ontogeny was compressed, and this together with the very small size of the adult indicates a true miniaturisation. Whereas the likely control of the origin of the tiny C. ceciliae was basically progenesis, the extreme spinosity had a different origin; allometric growth or possibly peramorphosis. C. ceciliae is small enough for the spines to have appreciably retarded sinking through frictional effects, and this small trilobite is interpreted as a free-swimming or floating form.

AB - Several hundred specimens of a tiny olenid trilobite, Ctenopyge ceciliae sp. nov., have been found in stinkstone nodules in the upper Cambrian Peltura scarabaeoides Zone in southern Sweden. This exceptionally spinose form is known only from disarticulated specimens, but is quite well preserved, and all growth stages are represented. The early ontogenetic stages are exceptionally small, the protaspis being only half the size of that of the associated Peltura species. There may have been no more than three thoracic segments. Thus the whole ontogeny was compressed, and this together with the very small size of the adult indicates a true miniaturisation. Whereas the likely control of the origin of the tiny C. ceciliae was basically progenesis, the extreme spinosity had a different origin; allometric growth or possibly peramorphosis. C. ceciliae is small enough for the spines to have appreciably retarded sinking through frictional effects, and this small trilobite is interpreted as a free-swimming or floating form.

U2 - 10.1111/1475-4983.00224

DO - 10.1111/1475-4983.00224

M3 - Article

VL - 45

SP - 1

EP - 22

JO - Palaeontology

T2 - Palaeontology

JF - Palaeontology

SN - 1475-4983

ER -