Graptolites


Also found in: Dictionary, Medical.

graptolites

[′grap·tə‚līts]
(paleontology)

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

References in periodicals archive ?
EARLY ORDOVICIAN GRAPTOLITE AND GEOLOGY OF THE OUTCROPS OF VENADO RIVER (HUILA REGION)
Nemagraptid graptolites are a particularly important fossil group for Ordovician biostratigraphy.
Los metasedimentos (pizarras y filitas) con graptolites ordovicianos de la Cristalina caracterizados por Harrison (1930) y Botero (1940), suprayacen a los gneis y afloran en una faja al oeste de la zona estudiada.
Herein we provide new information on the chronostratigraphy of the "Siluro-Devonian" succession in the subsurface of West Texas based on conodonts from a core from the Pegasus field in Midland County, Texas, and a reevaluation of graptolites originally described by Decker (1942, 1952) from wells in adjoining Crane County.
She has a PhD from Cambridge and concentrates her research on the evolution of plankton and the functional morphology of graptolites.
2014), the top of the Acerocarina Superzone is delimited by the base of the Ordovician and is marked by the first influx of pelagic graptolites (Rhabdinopora flabelliforme parabola) in Scandinavia.
1985): Conodonts and associated graptolites from the late Early Devonian of east-central Alaska and western Yukon Territory.
On the distribution of graptolites in the Dictyonema shale of Estonia and the noncontemporaneity of its different facies.
About 30 species of pterobranch are known to exist today although 380-490 million years ago a group of these animals called graptolites were common across the prehistoric oceans.
En esta seccion se observo una serie de especimenes que fueron utiles para la interpretacion del ambiente de sedimentacion a partir de sus caracteristicas paleoecologicas, como los Hexactinelidos, que indican ambiente marino, proximo costero; los braquiopodos que sugiere un ambiente marino neritico de aguas tranquilas, y ademas se observaron graptolites como Dicranograptus nicholsoni, Dicranograptus caparoensis, Flexicalimene sp.
Correlation of Baltoscandian conodont zones with those of trilobites (Tjernvik 1956; Tjernvik & Johansson 1980) and graptolites (Cooper & Lindholm 1990; Lindholm 1991a) is mainly in agreement with Lofgren (1996).