graptolites

[′grap·tə‚līts]

(paleontology)

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 It might be outdated or ideologically biased.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

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References in periodicals archive

Phylogenetic analysis reveals that Rhabdopleura is an extant graptolite. Lethaia 46: 34-56.

Hemichordate Molecular Phylogeny Reveals a Novel Cold-Water Clade of Harrimaniid Acorn Worms

In Palaeoecology and Biostratigraphy of Graptolites. (Hughes, C.

Ordovician timescale in Estonia: recent developments/Eesti Ordoviitsiumi ajaskaala: uuemad andmed

Decker (1942, 1952) reported Ludlovian (Late Silurian) graptolites from the Frame Member from wells in Crane County, Texas.

Revision of ages of the Fusselman, Wristen, and Thirtyone Formations (Late Ordovician-Early Devonian) in the subsurface of West Texas based on conodonts and graptolites

The brachiopod data from the Lasnamagi RS possibly need future revision because, based on the characteristic graptolites (Mannil 1976, fig.

Diversity and biostratigraphic utility of Ordovician brachiopods in the East Baltic

Tremadocian graptolite fossils are preserved in the Bear River, Feltzen, and Lumsden Dam formations (White 2010a).

Stratigraphy, provenance, and tectonic setting of the Lumsden Dam and Bluestone Quarry formations (Lower Ordovician), Halifax Group, Nova Scotia, Canada

The Estonian graptolite argillite (GA), Tremadoc in age, is distributed in northern Estonia and on Vormsi and Hiiumaa islands.

Geochemical heterogeneity of Estonian graptolite argillite

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).

The Early Ordovician trilobite distribution and zonation of the East Baltic/Ida-Balti Vara-Ordoviitsiumi trilobiitide levik ja tsonaalsus

Spencer, J.W., 1878b, Graptolites of the Niagara formation: Canadian Naturalist, new series, v.

J.W. Spencer (1851-1921): his life in Canada, and his work on preglacial river valleys

Knowlton and Jackson (1994) have argued that--far more often than generally acknowledged--the apparent plasticity of coral reef cnidarians reflects genetic differentiation, Indeed, the literature provides numerous hints of genetic controls on size and form: genetically based, species-level differences in colony form within the Montastraea annularis complex (Weil and Knowlton, 1994); differences in regeneration among clones of the reef coral Stylophora pistillata (Rinkevich, 2000); age effects on the survival of stony corals (Hughes and Connell, 1987); graptolites with highly determinate patterns of colony size (Mitchell, 1986); and botryllid tunicates that exhibit zooid and colony senescence (Rinkevich et al., 1992).

Determinate growth and modularity in a gorgonian octocoral

Additional encrusting organisms on Ordovician hard substrates are sphenothallid worms, cornulitids, corals, articulate and inarticulate brachiopods, crustoid graptolites and problematica (Wilson 1985; Taylor & Wilson 2003).

The earliest cornulitid on the internal surface of the illaenid pygidium from the Middle Ordovician of Estonia