Property:Definition
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This is a property of type Text. It links to pages that use the form MstConcept.
C
Free swimming larval stage, typically with five sub-stages, characterized by excretion through maxillary glands, and progressive increase in number of body segments and posterior appendages (see Stachowitsch, 1992). +
Deposition of sands formed by the breakdown to the skeletons of living organisms +
An organism that moves across, up or down the substratum via movements of its legs, appendages or muscles (e.g. ''Carcinus''). +
A narrow crack in hard substratum where penetration is deeper than the width at the entrance; a crevice is <10 mm wide at the entrance, while a fissure is >10 mm (Hiscock ,1996) +
A taxon is Critically Endangered when the best available evidence indicates that it meets any of the criteria A to E for Critically Endangered (see Section V), and it is therefore considered to be facing an extremely high risk of extinction in the wild. +
Forming or resembling a crust (Thompson, 1995) that is solid or resistant to touch or pressure e.g. encrusting coralline algae or sea mats such as ''Umbonula littoralis''. +
Forming or resembling a crust (Thompson, 1995) that yields to the touch or pressure e.g. the gelatinous colonies of ''Botryllus schlosseri'' or soft cushions of sponges such as ''Halichondria'' sp. +
Free-swimming spherical larva, composed of a simple gastrovascular system and short comb-rows; resembles typical adult ctenophore (see Stachowitsch, 1992, Ruppert & Barnes, 1994). +
With straight sides and a circular section (Thompson, 1995). +
Free-swimming bryozoan larva, the body is triangular, compressed and enclosed in a bivalve shell (see Ruppert & Barnes, 1994). +
Final lecithotrophic larval stage, characterized by bivalved carapace, compound eyes, prehensile antennules and thoraic appendages (cirri) (see Stachowitsch, 1992). +
D
Where the species degrades marine infrastructures or archaeological sites. +
A taxon is Data Deficient when there is inadequate information to make a direct, or indirect, assessment of its risk of extinction based on its distribution and/or population status. A taxon in this category may be well studied, and its biology well known, but appropriate data on abundance and/or distribution are lacking. Data Deficient is therefore not a category of threat. Listing of taxa in this category indicates that more information is required and acknowledges the possibility that future research will show that threatened classification is appropriate. It is important to make positive use of whatever data are available. In many cases great care should be exercised in choosing between DD and a threatened status. If the range of a taxon is suspected to be relatively circumscribed, and a considerable period of time has elapsed since the last record of the taxon, threatened status may well be justified. +
Min Value +
