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Ekwipagetia
Yukoniidae S. Zhang, 1980 'nom. transl''. et ''emend''. Jell, ''in'' Whittington ''et al''., 1997 ''ex'' Yukoniinae S. Zhang in W. Zhang, Lu ''et al''., 1980is a small family of trilobites, belonging to the Eodiscina. Type genus and species ''Yukonia intermedia'' Palmer 1968 (Plate 2, figures 14, 17–19, 22, 23, 27, 28; text figure 4). Taxonomy The Yukoniidae probably descended from the Tsunyidiscidae and gave rise to the Eodiscidae. cited in Description Yukoniidae are typically isopygous, belonging to the Superfamily Eodiscoidea. The narrow glabella The glabella, in humans, is the area of skin between the eyebrows and above the nose. The term also refers to the underlying bone that is slightly depressed, and joins the two brow ridges. It is a cephalometric landmark that is just superior ... is usually parallel sided, anteriorly rounded and separated from smooth anterior border by broad (''sag''.) preglabellar field which occupies about 25% of cephalic length ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trilobite
Trilobites (; meaning "three-lobed entities") are extinction, extinct marine arthropods that form the class (biology), class Trilobita. One of the earliest groups of arthropods to appear in the fossil record, trilobites were among the most successful of all early animals, existing in oceans for almost 270million years, with over 22,000 species having been described. Because trilobites had wide diversity and an easily fossilized mineralised exoskeleton made of calcite, they left an extensive fossil record. The study of their fossils has facilitated important contributions to biostratigraphy, paleontology, evolution, evolutionary biology, and plate tectonics. Trilobites are placed within the clade Artiopoda, which includes many organisms that are morphologically similar to trilobites, but are largely unmineralised. The relationship of Artiopoda to other arthropods is uncertain. Trilobites evolved into many ecological niches; some moved over the seabed as predators, scavengers, or ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ekwipagetia
Yukoniidae S. Zhang, 1980 'nom. transl''. et ''emend''. Jell, ''in'' Whittington ''et al''., 1997 ''ex'' Yukoniinae S. Zhang in W. Zhang, Lu ''et al''., 1980is a small family of trilobites, belonging to the Eodiscina. Type genus and species ''Yukonia intermedia'' Palmer 1968 (Plate 2, figures 14, 17–19, 22, 23, 27, 28; text figure 4). Taxonomy The Yukoniidae probably descended from the Tsunyidiscidae and gave rise to the Eodiscidae. cited in Description Yukoniidae are typically isopygous, belonging to the Superfamily Eodiscoidea. The narrow glabella The glabella, in humans, is the area of skin between the eyebrows and above the nose. The term also refers to the underlying bone that is slightly depressed, and joins the two brow ridges. It is a cephalometric landmark that is just superior ... is usually parallel sided, anteriorly rounded and separated from smooth anterior border by broad (''sag''.) preglabellar field which occupies about 25% of cephalic length ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trilobite Families
Trilobites (; meaning "three-lobed entities") are extinction, extinct marine arthropods that form the class (biology), class Trilobita. One of the earliest groups of arthropods to appear in the fossil record, trilobites were among the most successful of all early animals, existing in oceans for almost 270million years, with over 22,000 species having been described. Because trilobites had wide diversity and an easily fossilized mineralised exoskeleton made of calcite, they left an extensive fossil record. The study of their fossils has facilitated important contributions to biostratigraphy, paleontology, evolution, evolutionary biology, and plate tectonics. Trilobites are placed within the clade Artiopoda, which includes many organisms that are morphologically similar to trilobites, but are largely unmineralised. The relationship of Artiopoda to other arthropods is uncertain. Trilobites evolved into many ecological niches; some moved over the seabed as predators, scavengers, or ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eodiscidae
Eodiscidae is a family of agnostid trilobites that lived during the final Lower Cambrian (late Toyonian) and the Middle Cambrian. They are small or very small, and have a thorax of two or three segments. Eodiscidae includes nine genera (see box). Taxonomy The Eodiscids probably descended from the agnostids of family Yukoniidae. cited in Description Like other agnostids, the body of eodiscids is diminutive, the headshield (or cephalon) and tailshield (or pygidium) are of approximately same size, with 2 or 3 thoracic segments in-between, each consisting of a horizontal inner portion that abruptly passes into an inclined outer portion (fulcrate). The central raised area of the cephalon (or glabella The glabella, in humans, is the area of skin between the eyebrows and above the nose. The term also refers to the underlying bone that is slightly depressed, and joins the two brow ridges. It is a cephalometric landmark that is just superior ...) is narrow, usually with par ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cambrian First Appearances
The Cambrian ( ) is the first geological period of the Paleozoic Era, and the Phanerozoic Eon. The Cambrian lasted 51.95 million years from the end of the preceding Ediacaran period 538.8 Ma (million years ago) to the beginning of the Ordovician Period 486.85 Ma. Most of the continents lay in the southern hemisphere surrounded by the vast Panthalassa Ocean. The assembly of Gondwana during the Ediacaran and early Cambrian led to the development of new convergent plate boundaries and continental-margin arc magmatism along its margins that helped drive up global temperatures. Laurentia lay across the equator, separated from Gondwana by the opening Iapetus Ocean. The Cambrian marked a profound change in life on Earth; prior to the Period, the majority of living organisms were small, unicellular and poorly preserved. Complex, multicellular organisms gradually became more common during the Ediacaran, but it was not until the Cambrian that fossil diversity seems to rapidly increa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Treatise On Invertebrate Paleontology
The ''Treatise on Invertebrate Paleontology,'' published from 1953–2007 by the Geological Society of America and the University of Kansas, then 2009–present by the University of Kansas Paleontological Institute, is a definitive multi-authored work of currently 55 volumes, written by more than 300 paleontologists, and covering every phylum, class, order, family, and genus of fossil and extant (still living) invertebrate animals. The prehistoric invertebrates are described as to their taxonomy, morphology, paleoecology, stratigraphic and paleogeographic range. However, taxa with no fossil record whatsoever have just a very brief listing. Publication of the decades-long ''Treatise on Invertebrate Paleontology'' is a work-in-progress; and therefore it is not yet complete: For example, there is no volume yet published regarding the post- Paleozoic era caenogastropods (a molluscan group including the whelk and periwinkle). Furthermore, when needed, previously published vol ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glabella
The glabella, in humans, is the area of skin between the eyebrows and above the nose. The term also refers to the underlying bone that is slightly depressed, and joins the two brow ridges. It is a cephalometric landmark that is just superior to the nasion. Etymology The term for the area is derived from the Latin Latin ( or ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally spoken by the Latins (Italic tribe), Latins in Latium (now known as Lazio), the lower Tiber area aroun ... , "smooth", feminine of ''glabellus'', "hairless". Function The glabella is a key anatomical landmark used in craniofacial measurements, including interglabellar distance, which helps assess facial proportions in aesthetics and surgery. It also contributes to facial expressions through the action of muscles like the frontalis and orbicularis oculi. In medical science The skin of the glabella may be used to measure ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
