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Title: Absolute axial growth and trunk segmentation in the early Cambrian trilobite Oryctocarella duyunensis
Abstract A short stratigraphic interval near Bulin in western Hunan (China) yields multiple specimens of the ~514-Myr-old oryctocarine trilobite Oryctocarella duyunensis . Size data obtained from these specimens indicate that, from meraspid degree 1 onward, degrees represent successive instars. Meraspid growth persisted until a terminal stage was reached, providing the first example of determinate growth in trilobites and, notably, in an early Cambrian species. The sample contains three varieties of such terminal stages, recognized as holaspids, with 9, 10, or 11 thoracic segments, respectively. During the meraspid phase, growth rates were not constant in this species. The pattern of growth seen in the Bulin assemblage differs modestly from that reported in the same species from two other localities, attesting to microevolutionary variation in developmental patterns among these collections.  more » « less
Award ID(s):
1849963 1850005
NSF-PAR ID:
10228789
Author(s) / Creator(s):
; ; ;
Editor(s):
Patzkowsky, M.
Date Published:
Journal Name:
Paleobiology
ISSN:
0094-8373
Page Range / eLocation ID:
1 to 16
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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