query: parent_taxon paciphacops
supports: Trilobites (meaning "three lobes") are a fossil group of extinct marine arthropods that form the class Trilobita. Trilobites form one of the earliest known groups of arthropods. The first appearance of trilobites in the fossil record defines the base of the Atdabanian stage of the Early Cambrian period, and they flourished throughout the lower Paleozoic era before beginning a drawn-out decline to extinction when, during the Devonian, all trilobite orders except the Proetids died out. Trilobites finally disappeared in the mass extinction at the end of the Permian about . The trilobites were among the most successful of all early animals, roaming the oceans for over 270 million years. The Cambrian Period (or ) was the first geological period of the Paleozoic Era, of the Phanerozoic Eon. The Cambrian lasted 55.6 million years from the end of the preceding Ediacaran Period 541 million years ago (mya) to the beginning of the Ordovician Period mya. Its subdivisions, and its base, are somewhat in flux. The period was established (as Cambrian series) by Adam Sedgwick, who named it after Cambria, the Latinised form of "Cymru", the Welsh name for Wales, where Britain's Cambrian rocks are best exposed. The Cambrian is unique in its unusually high proportion of lagerstätte sedimentary deposits, sites of exceptional preservation where "soft" parts of organisms are preserved as well as their more resistant shells. As a result, our understanding of the Cambrian biology surpasses that of some later periods. Phacopidae is a family of phacophid trilobites that ranges from the Lower Ordovician to the Upper Devonian, with representatives in all paleocontinents. Phacopida ("Lens-face") is an order of trilobite that lived from the Late Cambrian to the Late Devonian. It is made up of a morphologically diverse group of related suborders. Paciphacops is a genus of trilobites from the order Phacopida , suborder Phacopina . This genus is easily mistaken for the more common and popular genus Phacops and Kainops . It takes a careful eye to spot the difference . One major difference between Paciphacops and Phacops is that the central raised area ( or glabella ) of the headshield ( or cephalon ) extends beyond its anterior margin . The difference between Paciphacops and Kainops is that Kainops has more eye facets than Paciphacops . The skin ( or sclera ) is thickened and bulges compared to the edge of each lens . This genus can be found primarily in the United States and Australia . Some Known Species and Locations . Paciphacops birdsongensis , Tennessee . Paciphacops campbelli , Oklahoma . Paciphacops claviger , Nevada . Paciphacops logani , Oklahoma . Paciphacops crosslei , Australia . Paciphacops latigenalis , Australia . Phacops is a genus of trilobite in the order Phacopida, family Phacopidae, that lived in Europe, northwestern Africa, North America and China from the early until the very end of the Devonian. It was a rounded animal, with a globose head and large eyes, and probably fed on detritus. "Phacops" is often found rolled up, a biological defense mechanism that is widespread among smaller trilobites but further perfected in this genus. The Devonian is a geologic period and system of the Paleozoic, spanning 60 million years from the end of the Silurian, million years ago (Mya), to the beginning of the Carboniferous, Mya. It is named after Devon, England, where rocks from this period were first studied.
  The first significant adaptive radiation of life on dry land occurred during the Devonian. Free-sporing vascular plants began to spread across dry land, forming extensive forests which covered the continents. By the middle of the Devonian, several groups of plants had evolved leaves and true roots, and by the end of the period the first seed-bearing plants appeared. Various terrestrial arthropods also became well-established. Fish reached substantial diversity during this time, leading the Devonian to often be dubbed the "Age of Fish". The first ray-finned and lobe-finned bony fish appeared, while the placodermi began dominating almost every known aquatic environment. In biology, detritus is dead particulate organic material (as opposed to dissolved organic material). It typically includes the bodies or fragments of dead organisms as well as fecal material. Detritus is typically colonized by communities of microorganisms which act to decompose (or remineralize) the material. In terrestrial ecosystems, it is encountered as leaf litter and other organic matter intermixed with soil, which is referred to as humus. Detritus of aquatic ecosystems is organic material suspended in water and piles up on seabed floors which is referred to as marine snow.
  Theory.
  Dead plants or animals, material derived from animal tissues (such as skin cast off during moulting et cetera) gradually lose their form, due to both physical processes and the action of decomposers, including grazers, bacteria and fungi. Decomposition, the process through which organic matter is decomposed, takes place in many stages. Materials like proteins, lipids and sugars with low molecular weight are rapidly consumed and absorbed by micro-organisms and organisms that feed on dead matter. Other compounds, such as complex carbohydrates are broken down more slowly. The various micro-organisms involved in the decomposition break down the organic materials in order to gain the resources they require for their own survival and proliferation. Accordingly, at the same time that the materials of plants and animals are being broken down, the materials (biomass) making up the bodies of the micro-organisms are built up by a process of assimilation. When micro-organisms die, fine organic particles are produced, and if these are eaten by small animals which feed on micro-organisms, they will collect inside the intestine, and change shape into large pellets of dung. As a result of this process, most of the materials from dead organisms disappears from view and is not obviously present in any recognisable form, but is in fact present in the form of a combination of fine organic particles and the organisms using them as nutrients. This combination is detritus. Kainops is a genus of trilobites from the family Phacopidae, order Phacopida. It can be distinguished from "Paciphacops" by the greater number of facets to the eye (68 per row, compared to 34 in "Paciphacops"). The form of the furrow between the palpebral area and the palpebral lobe also distinguishes "Kainops" from the genera "Paciphacops" and "Viaphacops".
candidates: animal area bacteria lens mya phacopida phacopidae phacops placodermi trilobita
answer: phacopidae