Pdf on jan 1, 2009, maria gabriela cuezzo and others published mollusca. Pdf on nov 1, 2017, victoriano urgorri and others published filo mollusca, clase gastropoda. Taxonomic hierarchy of monoplacophora nature mapping. Monoplacophora no common name laevipilina antarctica. Mollusca classification class aplacophora wormlike animals with bilateral symmetry.
The scaphopoda are the class with the smallest number of species in the mollusca. One solitary shell covers the pallium that extends over the dorsum. A summary of reports of abyssal and hadal monoplacophora and polyplacophora mollusca. Pdf on dec 17, 2015, julia sigwart and others published mollusca. Pdf on nov 1, 2017, victoriano urgorri and others published filo mollusca, clase monoplacophora. Start studying phylum mollusca class monoplacophora. Monoplacophorans and the origin and relationships of mollusks.
Monoplacophora are bilaterally symmetrical with internal metamerism. Phylum mollusca, class aplacophora, class monoplacophora. Mollusca classification class aplacophora class polyplacophora class gastropoda class monoplacophora class pelecypoda class scaphopoda class cephalopoda. Learn vocabulary, terms, and more with flashcards, games, and other study tools. The difference is that behind the mouth is a curious cluster of frondlike appendages that serve to push the food into the pharynx. Goldberg gastropod univalve pelecypod bivalve polyplacophora chiton scaphopod tusk cephalopod nautilus aplacophora monoplacophora. High pressure of blood vessel p2 forces fluid through a filter podocytes which may be homologous with the terminal cell of protonephridia to the lower press coelomic cavity p1. At the end of your monthly term, you will be automatically renewed at the promotional monthly subscription rate until the end of the promo period, unless you elect to. Head, foot, mantle, nephridia and shell are absent. They are all marine and so far about fifteen living species have been discovered. Body bilaterally symmetrical and remains covered by a mantle. Filo mollusca classe aplacophora classe monoplacophora 2. More on morphology monoplacophorans are small and limpetlike, having a single, caplike shell.
Monoplacophora article about monoplacophora by the free. One species was dredged up from the pacific ocean off mexico in 1952. The calcareous shell is bilaterally symmetrical, oval, and with a subcentral to anterior apex so that it is capshaped to spoonshaped. Phylum mollusca class monoplacophora questions and study. It was found to be a monoplacophoran, and given the genus of neopilina. The small number of deep water species living today such as neopilina may be relics of a much larger and more widespread group of ancestral molluscs dating back to the. They were wellknown as a fossil group from the cambrian to the devonian. Caudofoveata, monoplacophora, polyplacophora, scaphopoda, solenogastres. Pdf mollusca, solenogastres, caudofoveata, monoplacophora. The digestive system is very similar to that of the gastropods. Ncert books pdf download 2020 for class 12, 11, 10, 9, 8. Monoplacophora definition of monoplacophora by the free. Monoplacophora phylum mollusca 1 a class of primitive, almost bilaterally symmetrical 2, univalved molluscs, whose limpetshaped shell of calcium carbonate 3 consists of an external periostracum 4, a prismatic layer, and an internal, nacreous 5 deposit. Wikimedia commons ruggiero ma, gordon dp, orrell tm, bailly n, bourgoin t, brusca rc, et al.
The apex of the shell is forward on the monoplacophorans the shell is relatively. Offer starts on jan 8, 2020 and expires on sept 30, 2020. The seven classes of mollusks article under development by richard l. Only one specie of monoplacophora is known from mediterranean sea, found in some localities of tyrrhenian sea corsica, sardinia, capraia. The reason that i am so rarely found is that i live in very deep water, well below 200 to 600 meter mile depth level and that there appear to be only a very few of us living today. Problems arise from the ambiguous position of some paleozoic fossil taxa which could be monoplacophorans or gastropods, or worse stemgroup gastropods derived from monoplacophorans, thus making monoplacophora paraphyletic. Monoplacophora a class of mollusca which contains neopilina, a limpetlike deepsea form, which is known mainly from extinct forms. Unfortunately, there have thus far been no developmental studies done on monoplacophorans. Evidence for a clade composed of molluscs with serially. Lemche, 1957, and its relatives runnegar and pojeta 1974, 1985. Ncert books pdf free download for class 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, and 1 april 14, 2020 by kishen 16 comments there are many books in the market but ncert books stand alone in the market.
Gastropoda 40,000 sp bivalvia 7,650 sp other 5 classes 1100 polyplacophora cephalopoda molluscan taxonomic classes gastropoda scaphopoda bivalvia and aplacophora monoplacophora cretaceous triassic polyplacophora rostriconchians gastropoda bivalvia cephalopoda monoplacophora scaphopoda devonian. The following 3 files are in this category, out of 3 total. Possibly representive of the primitive molluscan condition or a secondary reduction from more advanced, shelled ancestors. A new species of monoplacophora, redescription of the genera veleropilina and rokopella, and new information on three species of the class. Monoplacophorans monohplakohforans look like limpets, but their single round shell, or valve, is bilaterally symmetrical. The rest of the monoplacophora members are only known by their fossil records.
Extant representatives were not recognized as such until 1952. Indeed, most of our knowledge about monoplacophora comes from the first description of neopilina galathaea by lemche and wingstrand in 1959. Aplacophora 320 especies, monoplacophora 20 especies. Members of this class have a single, capshaped shell similar to a limpet. Each class is introduced by a study of its systematic position, geographical distribution, morphology and anatomy of adults, features of nonadult. Monoplacophora, meaning bearing one plate, is a polyphyletic superclass of molluscs with a caplike shell now living at the bottom of the deep sea. They are found in deep water from 200 m to over 7000 m. Monoplacophora common names monoplacophorans in english mutsslakken in dutch mutsweekdieren in dutch in japanese bibliographic references. Monoplacophora monoplacophorans monoplacophora, meaning bearing one plate, is a polyphyletic class of mollusks with a caplike shell, living on the bottom of deep sea. Rearrange individual pages or entire files in the desired order. Monoplacophora simple english wikipedia, the free encyclopedia. The apex of the shell is forward on the monoplacophorans the shell is relatively small ranging in size from 3 to 30 mm in diameter.
Bilaterally symmetrical, with broad flat foot and single shell, mantle cavity has five to six pairs of gills. Oral groove, cytostome, cytopharynx, food vacuole, cytoproct for digestion. The phylum also provides some of the most familiar animals, such as snails, clams, mussels, squids, and octopus which, like the arthropods, are well known because theyre good to eat. The term tryblidia is preferred over monoplacophoran and galeroconcha, because both latter terms are taken to include several fossil groups of. Mollusca clases polyplacophora, caudofoveata, solenogastra. Monoplacophora synonyms, monoplacophora pronunciation, monoplacophora translation, english dictionary definition of monoplacophora. Find, read and cite all the research you need on researchgate. The monoplacophora and polyplacophora, groups with serially repeated structures in the mollusks, emerge as a monophyletic group that is sister to one group of the bivalvia pteromorphia. Links polyplacophora introduction to the group gives a comprehensive list of orders, families and genera, but no other information as yet other than a reference for each, the reference gives the author and year and page number, but no link to a bibliography the menu without frames here. The phylum mollusca also includes lesser known forms such as the chitons, tusk shells, solenogasters, among others. Although the shell of many monoplacophorans is limpetlike in shape, they are not gastropods, nor do they have any close relation to gastropods.
618 909 726 21 85 867 1278 221 1270 348 1503 302 569 1415 970 737 1310 750 662 681 1376 551 601 675 616 747 60 601 336 300 689 933 279