|
Eunicida
Eunicida is an order of polychaete worms. Characteristics Members of this order have an elongated, segmented body and a distinct head, normally with a separate peristomium and prostomium. Many, but not all, live in tubes which vary from a mucous sheath to a tough, horny casing. The palps vary from globular to cylindrical and there are from 0 to 7 antennae, usually smooth but occasionally jointed. There is a muscular pharynx with a dorsal pair of mandibles and a set of ventral, toothed, maxillary plates. Some species have tentacular cirri and all have unbranched parapodia. In some species, dorsal cirri, branchiae, ventral cirri and chaetae occur, but not in others. Natural History Museum. Retrieved 2012-01-17. Fossil record The |
Largest Prehistoric Animals
The largest prehistoric animals include both vertebrate and invertebrate species. Many of them are described below, along with their typical range of size (for the general dates of extinction, see the link to each). Many species mentioned might not actually be the largest representative of their clade due to the incompleteness of the fossil record and many of the sizes given are merely estimates since no complete specimen have been found. Their body mass, especially, is largely conjecture because soft tissue was rarely fossilized. Generally the size of extinct species was subject to energetic and biomechanical constraints. Non-mammalian synapsids (Synapsida) Caseasaurs (Caseasauria) The herbivorous ''Alierasaurus'' was the largest caseid and the largest amniote to have lived at the time, with an estimated length around . '' Cotylorhynchus hancocki'' is also large, with an estimated length and weight of at least and more than . Edaphosaurids (Edaphosauridae) The larges ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Websteroprion
''Websteroprion'' ("Webster's saw") is a genus of eunicidan polychaete that lived during the middle Devonian period in what is now Canada. It contains a single species, ''W. armstrongi'', recovered from the Kwataboahegan Formation. Etymology The genus was named after the bassist Alex Webster of the death metal band Cannibal Corpse. Description ''Websteroprion'' is known from the maxillae of several individuals in one location. These maxillae reaching in length, with one incomplete specimen that supposed to be bigger in full size. These are the largest jaws of any fossil polychaete. A larger fossil jaw had been reported in 1934Eller E. R. Annelid jaws from the Hamilton group of Ontario County, New York. Ann. Carnegie Mus. 24, 51–56 (1934). but that specimen is too undiagnostic so it regarded as a ''nomen dubium''. Referencing the jaw to body size ratio of other polychaetes, ''Websteroprion'' could have grown to long, though the exact size is unknown without soft tissue p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eunice Aphroditois
''Eunice aphroditois'' is a benthic bristle worm of warm marine waters. It lives mainly in the Atlantic Ocean, but can also be found in the Indo-Pacific. It ranges in length from less than to . Its iridescent cuticle produces a wide range of colors, from black to purple. This species is an ambush-predator; it hunts by burrowing its whole body in soft sediment on the ocean floor and waiting until its antennae detect prey. It then strikes with its sharp mouthparts. It may also be found among coral reefs. ''E. aphroditois'' is commonly known as the ''sand-striker'' or ''bobbit-worm''; the latter name is from the John and Lorena Bobbitt case. Description These ambush predators have no eyes and five antennae on their head that are used to sense prey. The body is covered by a hard exoskeleton. The mandibles can be retracted inside the body and are responsible for striking and stunning prey; they are capable of snapping some prey in half. Typically, ''E. aphroditois'' ranges from dee ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Annelid Orders
The annelids (Annelida , from Latin ', "little ring"), also known as the segmented worms, are a large phylum, with over 22,000 extant species including ragworms, earthworms, and leeches. The species exist in and have adapted to various ecologies – some in marine environments as distinct as tidal zones and hydrothermal vents, others in fresh water, and yet others in moist terrestrial environments. The Annelids are bilaterally symmetrical, triploblastic, coelomate, invertebrate organisms. They also have parapodia for locomotion. Most textbooks still use the traditional division into polychaetes (almost all marine), oligochaetes (which include earthworms) and leech-like species. Cladistic research since 1997 has radically changed this scheme, viewing leeches as a sub-group of oligochaetes and oligochaetes as a sub-group of polychaetes. In addition, the Pogonophora, Echiura and Sipuncula, previously regarded as separate phyla, are now regarded as sub-groups of polychaetes. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ichthyotomidae
Ichthyotomidae is a family of polychaetes belonging to the order Phyllodocida Phyllodocida is an order of polychaete worms in the subclass Aciculata. These worms are mostly marine, though some are found in brackish water. Most are active benthic creatures, moving over the surface or burrowing in sediments, or living in cr .... Genera: * '' Ichthyonomis'' * '' Ichthyotomus'' Eisig, 1906 References Polychaetes {{annelid-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mandible
In anatomy, the mandible, lower jaw or jawbone is the largest, strongest and lowest bone in the human facial skeleton. It forms the lower jaw and holds the lower tooth, teeth in place. The mandible sits beneath the maxilla. It is the only movable bone of the skull (discounting the ossicles of the middle ear). It is connected to the temporal bones by the temporomandibular joints. The bone is formed prenatal development, in the fetus from a fusion of the left and right mandibular prominences, and the point where these sides join, the mandibular symphysis, is still visible as a faint ridge in the midline. Like other symphyses in the body, this is a midline articulation where the bones are joined by fibrocartilage, but this articulation fuses together in early childhood.Illustrated Anatomy of the Head and Neck, Fehrenbach and Herring, Elsevier, 2012, p. 59 The word "mandible" derives from the Latin word ''mandibula'', "jawbone" (literally "one used for chewing"), from ''wikt:mandere ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Errantia
Errantia is a diverse group of marine polychaete worms in the phylum Annelida. Traditionally a subclass of the paraphyletic class "Polychaeta", it is currently regarded as a monophyletic group within the larger Pleistoannelida, composed of Errantia and Sedentaria. These worms are found worldwide in marine environments and brackish water. Phylogeny The phylogeny of polychaetes is slowly being resolved. Errantia and Sedentaria are the two biggest clades of polychaetes, and together they compose clade Pleistoannelida. Two groups are nested within Errantia: Aciculata (Eunicida + Phyllodocida) and Protodriliformia (small meiofaunal worms such as the Protodrilida). Historically, the order Amphinomida was part of this subclass. However, phylogenetic analyses place Amphinomida inside a basal clade with Sipunculida and '' Lobatocerebrum'', and this clade is the sister group to Pleistoannelida. Some taxa, such as Spintheridae and Myzostomida, are still difficult to place due to their lon ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
World Register Of Marine Species
The World Register of Marine Species (WoRMS) is a taxonomic database that aims to provide an authoritative and comprehensive list of names of marine organisms. Content The content of the registry is edited and maintained by scientific specialists on each group of organism. These taxonomists control the quality of the information, which is gathered from the primary scientific literature as well as from some external regional and taxon-specific databases. WoRMS maintains valid names of all marine organisms, but also provides information on synonyms and invalid names. It is an ongoing task to maintain the registry, since new species are constantly being discovered and described by scientists; in addition, the nomenclature and taxonomy of existing species is often corrected or changed as new research is constantly being published. Subsets of WoRMS content are made available, and can have separate badging and their own home/launch pages, as "subregisters", such as the ''World List of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Scolecodont
A scolecodont is the jaw of a polychaete annelid, a common type of fossil-producing segmented worm useful in invertebrate paleontology. Scolecodonts are common and diverse microfossils, which range from the Cambrian period (around half a billion years ago at the start of the Paleozoic era) to the present. They diversified profusely in the Ordovician, and are most common in the Ordovician, Silurian and Devonian marine deposits of the Paleozoic era. Relatedly, more problematic worm-like fossils have been described in even older, Neoproterozoic era deposits in the Ediacaran Hills of southern Australia and in mid-Cambrian deposits of Burgess shale in British Columbia. Since the other classes of annelids (specifically, the earthworms and leeches) lack hard parts, only the sea-dwelling polychaetes are frequently represented in the fossil record. Polychaetes are commonly fossilized due to their chitinous teeth and their dwelling tubes made of durable calcite (a calcium carbonate), ha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eunicidae
Eunicidae is a family of marine polychaetes (bristle worms). The family comprises marine annelids distributed in diverse benthic habitats across Oceania, Europe, South America, North America, Asia and Africa. The Eunicid anatomy typically consists of a pair of appendages near the mouth (mandibles) and complex sets of muscular structures on the head (maxillae) in an eversible pharynx. One of the most conspicuous of the eunicids is the giant, dark-purple, iridescent " Bobbit worm" (''Eunice aphroditois''), a bristle worm found at low tide under boulders on southern Australian shores. Its robust, muscular body can be as long as 2 m. Eunicidae jaws are known from as far back as Ordovician sediments. Cultural tradition surrounds Palola worm (''Palola viridis'') reproductive cycles in the South Pacific Islands. Eunicidae are economically valuable as bait in both recreational and commercial fishing. Commercial bait-farming of Eunicidae can have adverse ecological impacts. Bait-far ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hartmaniellidae
Hartmaniellidae is a family of polychaetes belonging to the order Eunicida Eunicida is an order of polychaete worms. Characteristics Members of this order have an elongated, segmented body and a distinct head, normally with a separate peristomium and prostomium. Many, but not all, live in tubes which vary from a mucou .... Genera: * '' Hartmaniella'' Imajima, 1977 References Polychaetes {{annelid-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Devonian
The Devonian ( ) is a geologic period and system of the Paleozoic era, spanning 60.3 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. The arthropod groups of myriapods, arachnids and hexapods also became well-established early in this period, after starting their expansion to land at least from the Ordovician period. Fish reached substantial diversity during this time, leading the Devonian to often be dubbed the Age of Fishes. The placoderms began dominating ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
.jpg "Click for more on -> Eunice Aphroditois")
