10.5061/DRYAD.825FF
Zhang, Zhiliang
Uppsala University
Northwest University
Zhang, Zhifei
Northwest University
Holmer, Lars E.
Uppsala University
Northwest University
Chen, Feiyang
Northwest University
Data from: Post-metamorphic allometry in the earliest acrotretoid
brachiopods from the lower Cambrian (Series 2) of South China, and its
implications
Dryad
dataset
2018
lower Cambrian
acrotretoid brachiopods
Eohadrotreta
2018-10-04T00:00:00Z
2018-10-04T00:00:00Z
en
https://doi.org/10.1111/pala.12333
123639 bytes
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CC0 1.0 Universal (CC0 1.0) Public Domain Dedication
The earliest growth of post-metamorphic (post-larval) shells in two
species of Eohadrotreta is described from the Cambrian Shuijingtuo
Formation of South China. Two different growth patterns can be observed by
quantifying developmental variations in size and shape of successive
stages of post-metamorphic shell growth (including the pedicle foramen
forming stage, pedicle foramen enclosing stage and intertrough increasing
stage) of Eohadrotreta zhenbaensis and Eohadrotreta? zhujiahensis. The
pedicle foramen is never enclosed within the metamorphic shell of E.
zhenbaensis, while the enclosed pedicle foramen of E.? zhujiahensis is
located directly outside the metamorphic shell after the pedicle foramen
enclosing stage. A strongly allometric growth pattern of E. zhenbaensis is
demonstrated by the early enclosure of the pedicle foramen; an accelerated
lengthening of the ventral intertrough is associated with the development
of a more complex dorsal median septum during the intertrough increasing
stage. By contrast, E.? zhujiahensis demonstrates possible paedomorphic
development by delayed enclosure of pedicle foramen and an associated
decreased lengthening of ventral intertrough during the intertrough
increasing stage. This ontogenetic developmental sequence represents the
marginal accretionary formation and growth of the pedicle foramen, which
resembles that of linguloid brachiopods. Furthermore, the developmental
process of the pedicle foramen of Eohadrotreta seems to recapitulate the
likely evolutionary transition from the Botsfordiidae, with open
delthyrium, to the Acrotheloidea, with an enclosed foramen. This study
provides a unique opportunity to obtain a complete understanding of the
ontogenetic development of the earliest acrotretoids, and casts new light
on the phylogeny of lingulate brachiopods.
Appendix S1Average dimensions and ratios of ventral valve of Eohadrotreta
zhenbaensis from the Cambrian (Series 2) Shuijingtuo Formation of the
Three Gorges area, South China, demonstrating the three ontogenetic
development stages respectively.Appendix S2Average dimensions and ratios
of ventral and dorsal valves of Eohadrotreta zhenbaensis from the Cambrian
(Series 2) Shuijingtuo Formation of the Three Gorges area, South China,
demonstrating the three ontogenetic development stages respectively,
including the whole ontogenetic development stages.Appendix S3Average
dimensions and ratios of ventral valve of Eohadrotreta? zhujiahensis from
the Cambrian (Series 2) Shuijingtuo Formation of the Three Gorges area,
South China, demonstrating the three ontogenetic development stages
respectively.Appendix S4Average dimensions and ratios of ventral and
dorsal valves of Eohadrotreta? zhujiahensis from the Cambrian (Series 2)
Shuijingtuo Formation of the Three Gorges area, South China, including the
whole ontogenetic development stages.