A TEST FOR THE POSSIBILITY OF PHOTOSYMBIOSIS IN EXTINCT FUSULINE FORAMINIFERA: SIZE AND SHAPE RELATED TO DEPTH OF HABITAT

Late Paleozoic fusuline foraminifera are thought to have hosted photosymbionts, as do modern larger foraminifera, but the ancient host-symbiont relationship has never been demonstrated conclusively. Among modern larger foraminifera, deeper-dwelling species exhibit large surface-to-volume ratios in o...

Full description

Saved in:
Bibliographic Details
Published in:Palaios 2012-10, Vol.27 (10), p.738-751
Main Authors: GROVES, JOHN R, PIKE, MADISON, WESTLEY, KASEY
Format: Article
Language:English
Subjects:
Carboniferous
Chautauqua County Kansas
Deer Creek Limestone
depth
Elk County Kansas
Foraminifera
Fossils
Fusulinidae
Fusulinina
Geology
habitat
Habitats
Invertebrata
invertebrate
Kansanella pauper
Kansas
Lecompton Limestone
Limestones
lithostratigraphy
microfossils
morphology
Oread Limestone
Oxygen
Paleontology
Paleozoic
Pennsylvanian
photochemistry
photosynthesis
Protista
Shales
size
Surface areas
Symbionts
Symbiosis
Taxa
tests
Triticites
United States
Upper Pennsylvanian
Virgilian
Citations: Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Late Paleozoic fusuline foraminifera are thought to have hosted photosymbionts, as do modern larger foraminifera, but the ancient host-symbiont relationship has never been demonstrated conclusively. Among modern larger foraminifera, deeper-dwelling species exhibit large surface-to-volume ratios in order to maximize the amount of sunlight that can be captured for use by photosymbionts. Shallower-dwelling species exhibit smaller surface-to-volume ratios in order to limit incoming sunlight, especially ultraviolet radiation. If modern symbiont-bearing foraminifera are appropriate analogues for fusulines, then deeper-dwelling fusulines ought to exhibit larger surface-to-volume ratios than shallower-dwelling ones. This prediction was tested by analyzing fusuline shells from the Virgilian (Upper Pennsylvanian) Oread, Lecompton and Deer Creek cyclothems in Kansas. Specimens from deeper-water "middle" limestones exhibit significantly larger surface-to-volume ratios than those from regressive "upper" limestones, and specimens with the smallest surface-to-volume ratios occur in shoaling deposits at or near the tops of regressive limestones. Shell shape does not vary predictably with depth of habitat. Rather, changes in surface-to-volume ratio were accomplished mainly by changes in size, with larger shells always characterized by smaller ratios. The observed trend is significantly nonrandom with respect to depth of habitat (p = 0.012). The trend is not likely the result of hydrodynamic adaptation, postmortem size sorting or size decrease along a bottom oxygen gradient. It most likely reflects geometric optimization for photosymbiosis.
ISSN:0883-1351
1938-5323
DOI:10.2110/palo.2012.p12-057r