Craniopsida

	Craniopsida Craniopsidae is an extinct family of craniiform brachiopods which lived from the Lower Cambrian (Botomian) to the Lower Carboniferous (Tournaisian). It is the only family in the monotypic In biology, a monotypic taxon is a taxonomic group (taxon) that contains only one immediately subordinate taxon. A monotypic species is one that does not include subspecies or smaller, infraspecific taxa. In the case of genera, the term "unispec ... superfamily Craniopsoidea and the monotypic order Craniopsida. Craniopsids were among the earliest and simplest brachiopods to appear. The calcitic shell was rounded in profile and biconvex, with both valves equally convex. Like other craniiforms, they had two pairs of adductor (vertical closing) muscles and two pairs of oblique (diagonal sliding) muscles, with the muscle scars shifted to near the center of the shell. They show some similarities with kirengellids, a group of problematic Cambrian fossil shells of marine organisms. References ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
	Craniopsida Craniopsidae is an extinct family of craniiform brachiopods which lived from the Lower Cambrian (Botomian) to the Lower Carboniferous (Tournaisian). It is the only family in the monotypic In biology, a monotypic taxon is a taxonomic group (taxon) that contains only one immediately subordinate taxon. A monotypic species is one that does not include subspecies or smaller, infraspecific taxa. In the case of genera, the term "unispec ... superfamily Craniopsoidea and the monotypic order Craniopsida. Craniopsids were among the earliest and simplest brachiopods to appear. The calcitic shell was rounded in profile and biconvex, with both valves equally convex. Like other craniiforms, they had two pairs of adductor (vertical closing) muscles and two pairs of oblique (diagonal sliding) muscles, with the muscle scars shifted to near the center of the shell. They show some similarities with kirengellids, a group of problematic Cambrian fossil shells of marine organisms. References ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
	Craniops ''Craniops'' is an extinct genus of brachiopods in the family Craniopsidae with species known from the Ordovocian to the Devonian. ''C. curvata'', ''C. elegans'', ''C. estona'' and ''C. obtusa'' are from the Kukruse Stage (Ordovician) of Kohtla-Järve, in north-eastern Estonia. ''C. tenuis'' is a pooleville member of the Bromide Formation from the Middle and Upper Ordovician of Oklahoma.Amsden, T.W. Catalogue of Fossils from the Middle and Upper Ordovician of Oklahoma. Oklahoma Geological Survey, Circular 43. 1957 See also * List of brachiopod genera This is a list of brachiopod genera which includes both extinct (fossil) forms and extant (living) genera (bolded). Names are according to the conventions of the International Code of Zoological Nomenclature. A '' Aalenirhynchia'' '' Aberia'' ... References External links * * ''Craniops'' at fossiilid.info Prehistoric brachiopod genera Paleozoic brachiopods Craniopsida Ordovician first appearances Devonian ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
picture info	Craniiforma Craniata is a class of brachiopods originating in the Cambrian period and still extant today. It is the only class within the subphylum Craniiformea, one of three major subphyla of brachiopods alongside linguliforms and rhynchonelliforms. Craniata is divided into three orders: the extinct Craniopsida and Trimerellida, and the living Craniida, which provides most information on their biology. Living members of the class have shells which are composed of calcite, though some extinct forms my have aragonite shells. The shells are inarticulate (lack a hinge with distinct tooth-and-socket connections) and are usually rounded in outline. There is no pedicle, with the rear edge of the body cavity having the form of a smooth and flat wall perforated by the anus. This class of brachiopods has an unsupported lophophore with only a single row of tentacles. In the absence of a pedicle, the shell is usually attached directly to a hard substrate. Many craniiforms are encrusting animals whic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
picture info	Brachiopod Families Brachiopods (), phylum Brachiopoda, are a phylum of trochozoan animals that have hard "valves" (shells) on the upper and lower surfaces, unlike the left and right arrangement in bivalve molluscs. Brachiopod valves are hinged at the rear end, while the front can be opened for feeding or closed for protection. Two major categories are traditionally recognized, articulate and inarticulate brachiopods. The word "articulate" is used to describe the tooth-and-groove structures of the valve-hinge which is present in the articulate group, and absent from the inarticulate group. This is the leading diagnostic skeletal feature, by which the two main groups can be readily distinguished as fossils. Articulate brachiopods have toothed hinges and simple, vertically-oriented opening and closing muscles. Conversely, inarticulate brachiopods have weak, untoothed hinges and a more complex system of vertical and oblique (diagonal) muscles used to keep the two valves aligned. In many brachiopods, a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]