Definition: A taxon is Extinct when there is no reasonable doubt that the last individual has died. A
taxon is presumed Extinct when exhaustive surveys in known and/or expected habitat,
at appropriate times (diurnal, seasonal, annual), throughout its historic range have failed
to record an individual. Surveys should be over a time frame appropriate to the taxon’s
life cycle and life form.
Definition: the transition region between the surf zone and the middle of the shelf, typically spanning water depths from a few meters to a few tens of meters.
Definition: Repeated, thickened, raised structures on the shell or carapace surface, comparable to or greater than the thickness of the shell/carapace and covering a notable portion of it. Thickenings can be either radial, comarginal, axial or spiral.
Definition: Repeated, thickened, raised structures on the shell or carapace surface, comparable to or greater than the thickness of the shell/carapace and covering a notable portion of it. Thickenings can be either radial, comarginal, axial or spiral.
Definition: A group of species that exploit the same food resources, and/or use the same feeding or foraging methods. http://en.wikipedia.org/wiki/Guild_(ecology)
Definition: A group of species that exploit the same food resources, and/or use the same feeding or foraging methods. http://en.wikipedia.org/wiki/Guild_(ecology)
