Variation in oxygen consumption among 'living fossils' (Mollusca: Polyplacophora)

Polyplacophoran molluscs (chitons) are phylogenetically ancient and morphologically constrained, yet multiple living species are often found co-occurring within widely overlapping ecological niches. This study used two sets of experiments to compare interspecific variation among co-occurring species...

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Bibliographic Details
Published in:Journal of the Marine Biological Association of the United Kingdom
Main Authors: Carey, Nicholas, Galkin, Alexander, Henriksson, Patrik, Richards, Jeffrey G., Sigwart, Julia D.
Format: Article in Journal/Newspaper
Language:English
Published: 2013
Subjects:
Online Access:https://pure.qub.ac.uk/en/publications/2a4ed3ac-ca30-4474-bf76-69d19094b458
https://doi.org/10.1017/S0025315412000653
Description
Summary:Polyplacophoran molluscs (chitons) are phylogenetically ancient and morphologically constrained, yet multiple living species are often found co-occurring within widely overlapping ecological niches. This study used two sets of experiments to compare interspecific variation among co-occurring species in the North Atlantic (Ireland) and separately in the North Pacific (British Columbia, Canada) chiton faunas. A complementary review of historical literature on polyplacophoran physiology provides an overview of the high level of metabolic variability in this group of 'living fossils'. Species examined in de novo experiments showed significant variation in oxygen consumption both under air-saturated water conditions (normoxia), and in response to decreasing oxygen availability (hypoxia). Some species demonstrate an ability to maintain constant oxygen uptake rates despite hypoxia (oxyregulators), while others oxyconform, with uptake rate dependent on ambient oxygen tension. These organisms are often amalgamated in studies of benthic communities, yet show obvious physiological difference that may impact their response or tolerance to environmental change.