Test flattening in the larger foraminifer Heterostegina depressa

Autor(en)
Wolfgang Eder, Johann Hohenegger, Antonino Briguglio
Abstrakt

Previous attempts to quantify the test-flattening trend in Heterostegina depressa with water depth have been rather unsuccessful. Due to its broad depth distribution, H. depressa is a perfect model species to calibrate test flattening as a bathymetric signal for fossil assemblages. This might enable us to better reconstruct paleoenvironments of fossil communities of larger foraminifera or even provide clues to the degree of transport in allochthonous deposits. In this study, we used growth-independent functions to describe the change of test thickness throughout ontogeny. Four growth-invariant characters, deriving from these functions, clearly quantify a transition of individuals with thicker to thinner central parts along the water-depth gradient. This transition is probably controlled by light intensity, because the photosymbionts of H. depressa (diatoms) are most effective at low irradiation levels. Thus, specimens at shallower depths grow thicker to reduce light penetration, whereas specimens living deeper than the light optimum increase their surface by flattening to obtain better exposure to light.

Organisation(en)
Institut für Paläontologie
Externe Organisation(en)
Università degli Studi di Genova
Journal
Paleobiology
Band
44
Seiten
76-88
Anzahl der Seiten
13
ISSN
0094-8373
DOI
https://doi.org/10.1017/pab.2017.24
Publikationsdatum
02-2018
Peer-reviewed
Ja
ÖFOS 2012
106054 Zoologie, 105118 Paläontologie
ASJC Scopus Sachgebiete
Ecology, Evolution, Behavior and Systematics, Ecology, Allgemeine Agrar- und Biowissenschaften, Palaeontology
Link zum Portal
https://ucrisportal.univie.ac.at/de/publications/89da15dd-a160-43cf-906d-9aa45245fc1e