taxon_rank saccocirridae
The Polychaeta or polychaetes are a paraphyletic ___MASK65___ of annelid worms , generally marine . Each body segment has a pair of fleshy protrusions called parapodia that bear many bristles , called chaetae , which are made of chitin . Indeed , polychaetes are sometimes referred to as bristle worms . More than 10 , 000 ___MASK44___ are described in this ___MASK65___ . Common representatives include the lugworm (" Arenicola marina ") and the sandworm or clam worm " Alitta ". A clade ( from , " klados ", " ___MASK11___ ") is a ___MASK72___ of organisms that consists of a common ancestor and all its lineal descendants , and represents a single " ___MASK11___ " on the " tree of life ". Ants are eusocial insects of the ___MASK95___ Formicidae and , along with the related wasps and bees , belong to the order Hymenoptera . Ants evolved from wasp - like ancestors in the Cretaceous period , about 99 million years ago and diversified after the rise of flowering plants . More than 12 , 500 of an estimated total of 22 , 000 species have been classified . They are easily identified by their elbowed antennae and the distinctive node - like structure that forms their slender waists . Worms are many different distantly related animals that typically have a long cylindrical tube - like body and no limbs . Worms vary in size from microscopic to over in length for marine polychaete worms ( bristle worms ), for the African giant earthworm , " Microchaetus ", and for the marine nemertean worm ( bootlace worm ), " Lineus longissimus ". Various types of worm occupy a small ___MASK16___ of parasitic niches , living inside the bodies of other animals . Free - living worm species do not live on land , but instead live in marine or freshwater environments , or underground by burrowing . Canalipalpata , also known as bristle - footed annelids or fan - head worms , is an ___MASK96___ of polychaete worms , with 31 families in it including the Sabellida ( tubeworms , fanworms , and feather duster worms ) and the Alvinellidae , a ___MASK95___ of deep - sea worms associated with hydrothermal vents . The Alvinellidae are a ___MASK95___ of small , deep - sea polychaete worms endemic to hydrothermal vents in the Pacific Ocean . Belonging to the order Terebellida , the ___MASK95___ contains two genera , Alvinella and Paralvinella ; the former genus contains two valid species and the latter eight . Members of the ___MASK95___ are termed alvinellids . The Saccocirridae are small interstitial polychaetes common in coarse sand on reflective , surf beaches , usually within the zone of retention . The Saccociridae are members of the clade Protodrilida , which is in turn part of the clade Canalipalpata . Saccocirridae have a world wide distribution and many more ___MASK44___ likely remain to be described . These polychates are usually between 2 and 10 mm in length and 500 m wide . They have reduced parapodia and are considered a true interstitial ___MASK44___ , incapable of burrowing through finer sediments . Sabellida is a ___MASK87___ of annelid worms in the class Polychaeta . They are filter feeders with no buccal organ . The prostomium is fused with the peristomium and bears a ring of feathery feeding tentacles . They live in parchment - like tubes made of particles from their environment such as sand and shell fragments cemented together with mucus . Members of the ___MASK87___ include the feather duster worms ( Sabellidae ) and serpulid worms ( Serpulidae ). Among the ___MASK44___ are the giant feather duster worm (" Eudistylia polymorpha "), the peacock worm (" Sabella pavonina "), the European fan worm (" Sabella spallanzanii ") and the Christmas tree worm (" Spirobranchus giganteus "). A hydrothermal vent is a fissure in a planet ' s surface from which geothermally heated water issues . Hydrothermal vents are commonly found near volcanically active places , areas where tectonic plates are moving apart , ocean basins , and hotspots . Hydrothermal vents exist because the earth is both geologically active and has large amounts of water on its surface and within its crust . Common land types include hot springs , fumaroles and geysers . Under the sea , hydrothermal vents may ___MASK3___ features called black smokers . Relative to the majority of the deep sea , the areas around submarine hydrothermal vents are biologically more productive , often hosting complex communities fueled by the chemicals dissolved in the vent fluids . Chemosynthetic bacteria and archaea ___MASK3___ the base of the food chain , supporting diverse organisms , including giant tube worms , clams , limpets and shrimp . Active hydrothermal vents are believed to exist on Jupiter ' s moon Europa , and Saturn ' s moon Enceladus , and it is speculated that ancient hydrothermal vents once existed on Mars .