272 D17. Paleontology, Paleoecology/Taphonomy (Posters)

Tuesday, 24 October 2017
9:00 AM - 6:30 PM
Halls 4EF

SUBSTRATE RELATIONSHIP GUIDED MOLLUSCAN BODY-SIZE RESPONSE TO CLIMATIC FLUCTUATION DURING THE PAST 66 MA

Paper number: 272-55
Program: Technical Sessions
Time: 9:00 AM – 6:30 PM

Authors

Abstract

Body size is a key factor in dictating the fate of interaction between an organism and its surrounding environment. A negative temperature-size relationship has been suggested as one of the universal responses to climatic warming. To confirm the generality of this relationship and to evaluate its dependence on existing body-size and latitudinal-range of marine families, we compiled the relationship between body-size and global temperature trends over Cenozoic using a database of marine benthic molluscs of class gastropoda and bivalvia resolved to temporal stages. We evaluated the dependence of climate induced body-size response to existing size and geographic range via correlating the first-difference coefficient of temperature-size relationship with maximum size and latitudinal range of family respectively.

Mean body-size and temperature estimates appear to track each other negatively when binned by geologic stages; however, it is not observable when the mean body-size and temperature time series are detrended by a first-differences transformation implying a lack of size-reduction due to climatic warming during Cenozoic. There exists a strong negative correlation between maximum body-size and ρ1st (size-temp) (the coefficient of correlation between 1st difference of mean body-size vs temperature) for infaunal families implying that families with smaller body-size tend to show higher magnitude of change with climatic fluctuation compared to bigger ones. Epifaunal families do not show such “existing size dependence”. A significant negative correlation for infaunal families also exists between ρ1st (size-temp) and latitudinal range implying that families with limited latitudinal range show higher magnitude of body-size change compared to widespread taxa. Such “latitudinal range dependence” is absent among epifaunal families. This difference in response between infauna and epifauna is due to the dissimilar thermal-sensitivity of these groups evolved due to their non-uniform exposure to thermal fluctuation. Our results highlight the dependence of climate induced morphological response on ecological character indicating the complexity in generalizing the biotic outcome of future climatic fluctuation.

Geological Society of America Abstracts with Programs. Vol. 49, No. 6

doi: 10.1130/abs/2017AM-295934

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