Amphistegina gibbosa

Super Group: 
Chromista
Phylum: 
Foraminifera
Class: 
Globothalamea
Order: 
Rotaliida
Family: 
Amphisteginidae
Genus: 
Amphistegina
Species: 
gibbosa
Authority: 
d'Orbigny, 1839

Diagnosis

Test: trochospiral, asymmetrically lenticular, involute with an angular, carinate periphery and lobed sutures, unequally biconvex;
Chamber: numerous, with interseptal pillars, strongly curved back at the periphery (alar prolongation); Aperture a narrow slit at the inner margin of the last chamber often surrounded by pustules

Life cycle

Test free, epibenthic, living in symbiosis with different symbionts (diatoms, which require blue light). The depth distribution is related to the light required by the specific symbionts. If water transparency is sufficient specimens may be found at greater depth up to 130m living together with symbionts used to little light and greater depth conditions. Due to these specific communities assemblages of calcareous algae and larger foraminifera are commonly used as proxy water-depth indicators in carbonate sediments with Amphistegina as one of its prominent representatives.
The robust tests especially of A. lobifera are adapted to a life in mobile carbonate sands and areas of increased turbidity and high hydrodynamic energy, characteristic of water depths less than 10m. Amphisteginas adjust the morphology of the apertural faces according to the needs for sticking to the substrate. They mainly live in the forereef-shelf and reef top.
Generation times are 3-12 months depending on depth and nutrition. For A. gibbosa a trimorphic life cycle is observed.

Observation site(s)

SYMBIONTS

Displaying 1 - 2 of 2
Association with... Region origin Name of site In reference...
Navicula sp. Florida Conch Reef
LEE JOHNJ, Morales J, Symons A, Hallock P (1995) Diatom symbionts in larger foraminifera from Caribbean hosts. Marine Micropaleontology 26:99 - 105. doi: 10.1016/0377-8398(95)00004-6
Nitzschia frustulum Florida Conch Reef
LEE JOHNJ, Morales J, Symons A, Hallock P (1995) Diatom symbionts in larger foraminifera from Caribbean hosts. Marine Micropaleontology 26:99 - 105. doi: 10.1016/0377-8398(95)00004-6

ASQME static network (beta)

ASQME dynamic network (beta)

ASQME map (beta)