graptolite

graptolite
—graptolitic /grap'teuh lit"ik/, adj.
/grap"teuh luyt'/, n.
any colonial animal of the extinct class Graptolithina, most common in the Ordovician and Silurian Periods, thought to be related to the pterobranchs.
[1830-40; < Gk graptó(s) painted, marked with letters (v. adj. from gráphein to write) + -LITE]

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Any member of an extinct group of small, aquatic colonial invertebrates that first became apparent during the Cambrian Period and persisted into the Early Carboniferous Period (354–323 million years ago).

Graptolites were floating animals that had tentacles and a hard outer covering. They most often have been preserved as impressions on black shales. Graptolite fossils show a gradual development through time, and evolutionary relationships between different graptolite groups have been discovered and analyzed.

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▪ fossil animal
      any member of an extinct group of small, aquatic colonial animals that first became apparent during the Cambrian Period (542 million to 488 million years ago) and that persisted into the Early Carboniferous Period (359 million to 318 million years ago). Graptolites were floating animals that have been most frequently preserved as carbonaceous impressions on black shales, but their fossils have been found in a relatively uncompressed state in limestones. They possessed a chitinous (fingernail-like) outer covering and lacked mineralized hard parts. When found as impressions, the specimens are flattened, and much detail is lost.

      The graptolite animal was bilaterally symmetrical and tentacled. It has been suggested that graptolites are related to the hemichordates, a primitive group of invertebrates. Graptolites have proved to be very useful for the stratigraphic correlation of widely separated rock units and for the finer division of Lower Paleozoic rock units (Cambrian to Devonian); examples include the genera Climacograptus, Clonograptus, Didymograptus, Diplograptus, Monograptus, Phyllograptus, and Tetragraptus. Graptolites show a gradual development through time, and evolutionary relationships between different graptolite groups have been discovered and analyzed.

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Universalium. 2010.

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Look at other dictionaries:

  • Graptolite — Grap to*lite, n. [NL, Graptolithus, from Gr. ? is engraved, written (gra fein to write) + ? stone.] (Paleon.) One of numerous species of slender and delicate fossils, of the genus {Graptolites} and allied genera, found in the Silurian rocks. They …   The Collaborative International Dictionary of English

  • graptolite — ● graptolite nom masculin (grec graptos, gravé) Stomocordé colonial fossile, présent dans les terrains cambriens et siluriens. (Les graptolites, organismes marins coloniaux stolonifères, forment une classe, proche de celle des ptérobranches.) …   Encyclopédie Universelle

  • graptolite — 1838, from Mod.L. graptolithus, lit. written stone, from Gk. graptos engraved, written, painted (verbal adj. of graphein; see GRAPHY (Cf. graphy)) + lithos stone. So called because the fossils resemble writing …   Etymology dictionary

  • Graptolite — Taxobox name = Graptolites fossil range = fossil range|510|350Mid Cambrian to Lower Carboniferous image width = 260px image caption = Fossil graptolite Tetragraptus fruticosus from the Ordovician of Australia regnum = Animalia phylum =… …   Wikipedia

  • Graptolite — Graptolite …   Wikipédia en Français

  • graptolite — noun Etymology: Greek graptos painted (from graphein to write, paint) + English lite more at carve Date: 1841 any of an extinct class (Graptolithina) of hemichordate colonial marine animals of the Paleozoic era with zooids contained in conical… …   New Collegiate Dictionary

  • graptolite — n. [Gr. graptos, painted; lithos, stone] A fossil group of pelagic, colonial animals with chitinous exoskeletons, consisting of simple or branched stems (rhabdosomes) toothed along one or both edges …   Dictionary of invertebrate zoology

  • graptolite — noun Any of a group of extinct aquatic colonial invertebrates, of the class Graptolithina, from the Cambrian and Carboniferous periods …   Wiktionary

  • graptolite — ► adjetivo/ sustantivo masculino ZOOLOGÍA Perteneciente a un grupo de organismos fósiles marinos de la era paleozoica, que vivían en colonias …   Enciclopedia Universal

  • graptolite — grap·to·lì·te s.m. TS paleont. fossile del Siluriano della classe dei Graptoliti | pl. con iniz. maiusc., classe del phylum degli Emicordati, rappresentata da forme coloniali che mostrano affinità con gli Idrozoi e con i Briozoi, dalla dubbia… …   Dizionario italiano

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