Definition: A taxon is Extinct when there is no reasonable doubt that the last individual has died. A \r\ntaxon is presumed Extinct when exhaustive surveys in known and/or expected habitat, \r\nat appropriate times (diurnal, seasonal, annual), throughout its historic range have failed \r\nto record an individual. Surveys should be over a time frame appropriate to the taxon’s life cycle and life form.
Definition: Siliceous ooze is a marine sediment composed of the debris of plankton with silica shells, such as diatoms and radiolaria. This ooze is limited to areas with high biological productivity, such as the polar oceans, and upwelling zones near the equator. The least common type of sediment, it covers only 15% of the ocean floor. It accumulates at a slower rate than calcareous ooze: 0.2-1 cm / 1000 yr.
Definition: Living in the fluid medium (water or air) but unable to maintain their position or distribution independently of the movement of the water/air mass (adapted from Lincoln et al., 1998).
Definition: Component found in mineralized skeletal tissue, (a specialized form of biogenic tissue in which the extracellular matrix is mineralized, and which functions in mechanical and structural support.)
Definition: number of homologous sets of chromosomes in the nucleus or primary chromosome-containing compartment of the cell, each set essentially coding for all the biological traits of the organism.
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)
Known occurrences, collected specimens and observations of Hemiaulus incurvus K. G. Schibkova ex A. I. Krotov & K. G. Schibkova 1959. View this species on GBIF
