Trilobitan.
/ˌtrʌɪlə(ʊ)ˈbʌɪtə/, /ˌtrɪlə(ʊ)ˈbʌɪtə/, U.S. /ˌtraɪləˈbaɪdə/, /ˌtrɪləˈbaɪdə/ Palaeontology.
With plural (or occasionally singular) agreement: a large group of extinct multi-legged arthropods that occurred abundantly in Palaeozoic seas, typically having a flattened oval body with a solid head section (cephalon) with antennae and compound eyes, a flexible segmented thorax, and a solid tail section (pygidium), all of which are divided into three longitudinal lobes. Also with plural agreement: animals of this group (collectively or individually); trilobites.Although considered to be a class, subphylum, or phylum (formerly an order) of arthropods, the relationship of the Trilobita to other arthropod groups is unclear. They are now sometimes regarded as a stem group ancestral to both the chelicerates and the crustaceans.
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the world > animals > invertebrates > phylum Arthropoda > trilobites > [noun] > member of
trilobite1805
Trilobita1835
1835 Rep. Brit. Assoc. Advancem. Sci. 1834 193 Latreille in his last work..has increased the orders still further. He has adopted three other new ones, called Dicladopa, Ostrapoda, and Trilobita.
1859 S. G. Goodrich Illustr. Nat. Hist. Animal Kingdom II. 613 This also seems to be the place for a family of fossil crustacea, the well-known Trilobites, Trilobita, of which vast numbers occur in some of the earlier strata of the earth's crust.
1893 T. R. R. Stebbing Hist. Crustacea i. 10 The name of the third order, the Trilobita, refers to the circumstance that they usually have the body divided by two longitudinal dorsal grooves into three lobes.
1931 Jrnl. Paleontol. 5 164 Eight [papers] dealt with the smaller foraminifera.., one with the Trilobita, and one with the petrographic characters of some Eocene sands.
1964 Philos. Trans. (Royal Soc.) B. 247 100 The Trilobita show clear general resemblances in leg form to the limbs of Limulus, but the Trilobita lack as good a gnathobase.
2001 G. C. McGavin Essent. Entomol. 15 The Uniramia..have single-branched limbs in contrast to the ‘biramous’ limbs of the Crustacea, Chelicerata and Trilobita.
Derivatives
triloˈbitan adj. Of or relating to the group Trilobita.
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1892 H. M. Bernard Apodidæ: Morpholog. Study xiii. 216 Strictly speaking the ridge and the shield were two independent developments of the primitive Trilobitan head-shield.
1958 Q. Rev. Biol. 33 42/1 The Merostomata lost the trilobitan antennae.
1993 E. N. K. Clarkson Invertebr. Palaeontol. & Evol. (ed. 3) xii. 400/1 It has..uniramous antennae and typically trilobitan appendages.
This entry has been updated (OED Third Edition, September 2009; most recently modified version published online March 2022).
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