Desmograptus. micronematodes, a silurian dendroid graptolite, and its ultrastructure

Saunders, K. M.; Bates, D. E. B.; Kluessendorf, J.; Loydell, D. K.; Mikulic, D. G.

Abstract:

Desmograptus micronematodes from Thornton quarry, Cook County, Illinois, USA, remarkably preserved in relief and encased in pyrite, is described. The internal details of the thecae, and of the stolon system, examined using the SEM, allow the reconstruction of the growth of a stipe. The stolons and stolonal nodes are formed of a dense crassal fabric, and are surrounded by a loose fabric of three-dimensional fibrils. The nodes have a complex structure of three boxes with proximal and distal nozzles. The base of a bitheca, and the base of each autothecal cup, has a central nozzle surrounded by a unique honeycomb fabric. The ultrastructure of the cortical fibrils, with their clockwise striations, is similar to that in Dendrograptus, and may be universal in the graptolites. The nodes of the stolon system appear identical to those of Acanthograptus and other dendroids, but differ from those of the extant hemichordate Rhabdopleura, which have only a diaphragm, and lack box structures. ?? The Palaeontological Association, 2009.

Genre:

Article

ProdID:

70034695

Citation Author:

Saunders, K. M.; Bates, D. E. B.; Kluessendorf, J.; Loydell, D. K.; Mikulic, D. G.

Citation Contributing Office:

Citation Datum:

Citation Day:

Citation Edition:

Citation Editor:

Citation End Page:

559

Citation Issue:

Citation Keywords:

Citation Language:

English

Citation Larger Work Title:

Palaeontology

Citation LatN:

Citation LatS:

Citation LonE:

Citation LonW:

Citation Month:

Citation No Pagination:

Citation Number Of Pages:

Citation Online Only Flag:

Citation Phsyical Description:

Citation Projection:

Citation Public Comments:

Citation Publisher:

Citation Series:

Citation Series Code:

Citation Series Number:

Citation Search Results Text:

Desmograptus. micronematodes, a silurian dendroid graptolite, and its ultrastructure; 2009; Article; Journal; Palaeontology; Saunders, K. M.; Bates, D. E. B.; Kluessendorf, J.; Loydell, D. K.; Mikulic, D. G.