Depth-related shape variation in Ammobaculites agglutinans (d’Orbigny)
Abstract
Zmienność kształtu zależna od głebokości w Ammobaculites agglutinans (d'Orbigny)
Specimens of Ammobaculites agglutinans from ALBATROSS stations in the North Atlantic can be separated into two populations relative to water depth. Specimens from abyssal calcareous oozes are larger in size and commonly possess more uniserial chambers than specimens from shallower depths on the continental margin. In addition, the amount of dimorphism between megalosphaeric and microsphaeric individuals increases with depth. These size and shape variations may allow abyssal populations to be distinguished from bathyal and neritic populations.
Specimens of Ammobaculites agglutinans from ALBATROSS stations in the North Atlantic can be separated into two populations relative to water depth. Specimens from abyssal calcareous oozes are larger in size and commonly possess more uniserial chambers than specimens from shallower depths on the continental margin. In addition, the amount of dimorphism between megalosphaeric and microsphaeric individuals increases with depth. These size and shape variations may allow abyssal populations to be distinguished from bathyal and neritic populations.