A rare double skeleton of the silicoflagellate &amp;lt;i&amp;gt;Corbisema&amp;lt;/i&amp;gt;

Kevin Mccartney,David M Harwood,Jakub Witkowski

doi:10.1144/0262-821x09-020

A rare double skeleton of the silicoflagellate &lt;i&gt;Corbisema&lt;/i&gt;

Kevin Mccartney, David M Harwood + Show 1 more

Open Access

https://doi.org/10.1144/0262-821x09-020

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Abstract

Silicoflagellates are usually associated with simple skeletons made of a domal latticework of rod-shaped elements, known as the apical structure, which is attached to a polygonal basal ring. Silicoflagellate reproduction is poorly understood (Moestrup & Thomsen, 1990) but they are known to divide mitotically associated with the construction of a double skeleton. Such double skeletons connected at the abapical face of the basal ring are observed from Recent and fossil material. Double skeletons of Dictyocha and Distephanus noted in Cenozoic sediments (Dumitricǎ, 1973, pl. 4, fig. 8; Boney, 1976) show basal rings positioned with their corners in close proximity. Ling & Takahashi (1985, pl. 1, fig. 5) and Takahashi et al . (2009, pl. 2, figs 3, 5) illustrate Distephanus with the spines of the two skeletons in exact alignment with one another. Recent work in a Campanian sequence of strata near Horton River, District of Mackenzie in the Northwest Territories, Canada …

Highlights

Silicoflagellates are usually associated with simple skeletons made of a domal latticework of rod-shaped elements, known as the apical structure, which is attached to a polygonal basal ring
Other Corbisema archangelskiana are common in this sample, with 189 specimens observed in two slides (20 40 mm cover slips)
Paired skeletons are an early feature of silicoflagellates, and preliminary evidence that Cretaceous Corbisema had corners of each skeleton aligned between the corners of the sibling member of a double skeleton pair

Summary

Introduction

Silicoflagellates are usually associated with simple skeletons made of a domal latticework of rod-shaped elements, known as the apical structure, which is attached to a polygonal basal ring. The discovery was made in sample C-8590 in a slide prepared in 1994 for diatom study (Tapia & Harwood, 2002) and is associated with a flora of Late Cretaceous silicoflagellates from the Cornua trifurcata Zone of Early Campanian age (McCartney et al, in press). This is the only example of a Corbisema double skeleton to have been photographed and the specimens preserved and connected in a host of matrix sediment.

Results

Conclusion