Graptolites

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graptolites

[′grap·tə‚līts]
(paleontology)
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.

Graptolites

 

(Graptolithina), a subphylum of extinct marine colonial animals of phylum Hemichordata.

Graptolites are known from the Cambrian to the Carboniferous periods; they were most common in the Ordovi-cian. Silurian, and lower Devonian periods. The skeletons of graptolites consisted of chitinous branches formed from little compartments in which the zooids lived. Graptolites were either benthic or planktonic. Planktonic graptolites had a swim bladder filled with gas released by the zooids as a product of their vital processes. There were two classes: Stereostolonata, with hard stolons and functionally varied compartments, and Graptoloidea, without stolons and with uniform compartments. Graptolites are of great importance as index fossils.

REFERENCE

Obut, A. M. “Tip Hemichordata (Gemikhordovye): Podtip Graptolithina (Graptolity).” In Osnovy paleontologii: Iglokozhie, gemikhordovye, pogonofory i shchetinkocheliustnve. Moscow, 1964.

A. M. OBUT

The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.
References in periodicals archive ?
Thermochemical Destruction of Graptolite Argillite.
Phylogenetic analysis reveals that Rhabdopleura is an extant graptolite. Lethaia 46: 34-56.
Between the Cambrian sand- and siltstones and Ordovician limestones occur the major sources of Rn: Lower-Ordovician obolus sandstone with P-rich layers of phosphorite that are overlain by graptolite argillite.
There is currently some confusion as to the definition of the base of the Amorphognathus tvaerensis Zone, and also regarding its relationship to the graptolite biozonation and to the base of the Upper Ordovician Series.
Geochemical heterogeneity of Estonian graptolite argillite.
Graptolite age control for the Llandovery-Wenlock Sangerville and Ludlow Smalls Falls formations in central Maine also constrains the ages of the intervening Perry Mountain and overlying Madrid formations (Table 2; Ludman and Griffin 1974; Pankiwskyj et al.
The boundary level coincides with the first appearance of the graptolite Diplacanthograptus caudatus (Lapworth), which is known from Australasia, Eastern North America, South Central USA, Scotland, Newfoundland (Goldman 2003), but not from the East Baltic.
In addition, graptolite colonies are believed to have had determinate growth leading to distinct species-specific forms and sizes (Mitchell, 1988).
In Proceedings of the 6th International Graptolite Conference (GWG-IPA) & 1998 Field Meeting, IUGS Subcommission on Silurian Stratigraphy (Gutierrez-Marco, J.
Available geological data indicate that the Lower Silurian graptolite shales represent the most prospective source rock body for shale gas exploration in west Lithuania.