Climate change, genetics or human choice: why were the shells of mankind’s earliest ornament larger in the Pleistocene than in the Holocene?

The southern African tick shell, Nassarius kraussianus (Dunker, 1846), has been identified as being the earliest known ornamental object used by human beings. Shell beads dated from ~75,000 years ago (Pleistocene era) were found in a cave located on South Africa's south coast. Beads made from N...

Full description

Bibliographic Details
Main Authors: Teske, Peter R, Papadopoulos, Isabelle, McQuaid, Christopher D, Newman, Brent K, Barker, Nigel P
Format: Others
Language:English
Published: 2007
Online Access:http://hdl.handle.net/10962/d1006001
http://dx.doi.org/10.1371/journal.pone.0000614
id ndltd-netd.ac.za-oai-union.ndltd.org-rhodes-vital-6545
record_format oai_dc
spelling ndltd-netd.ac.za-oai-union.ndltd.org-rhodes-vital-65452018-12-11T04:30:22ZClimate change, genetics or human choice: why were the shells of mankind’s earliest ornament larger in the Pleistocene than in the Holocene?Teske, Peter RPapadopoulos, IsabelleMcQuaid, Christopher DNewman, Brent KBarker, Nigel PThe southern African tick shell, Nassarius kraussianus (Dunker, 1846), has been identified as being the earliest known ornamental object used by human beings. Shell beads dated from ~75,000 years ago (Pleistocene era) were found in a cave located on South Africa's south coast. Beads made from N. kraussianus shells have also been found in deposits in this region dating from the beginning of the Holocene era (<10,000 years ago). These younger shells were significantly smaller, a phenomenon that has been attributed to a change in human preference. We investigated two alternative hypotheses explaining the difference in shell size: a) N. kraussianus comprises at least two genetic lineages that differ in size; b) the difference in shell size is due to phenotypic plasticity and is a function of environmental conditions. To test these hypotheses, we first reconstructed the species' phylogeographic history, and second, we measured the shell sizes of extant individuals throughout South Africa. Although two genetic lineages were identified, the sharing of haplotypes between these suggests that there is no genetic basis for the size differences. Extant individuals from the cool temperate west coast had significantly larger shells than populations in the remainder of the country, suggesting that N. kraussianus grows to a larger size in colder water. The decrease in fossil shell size from Pleistocene to Holocene was likely due to increased temperatures as a result of climate change at the beginning of the present interglacial period. We hypothesise that the sizes of N. kraussianus fossil shells can therefore serve as indicators of the climatic conditions that were prevalent in a particular region at the time when they were deposited. Moreover, N. kraussianus could serve as a biomonitor to study the impacts of future climate change on coastal biota in southern Africa.2007Article5 pagespdfvital:6545http://hdl.handle.net/10962/d1006001http://dx.doi.org/10.1371/journal.pone.0000614English
collection NDLTD
language English
format Others
sources NDLTD
description The southern African tick shell, Nassarius kraussianus (Dunker, 1846), has been identified as being the earliest known ornamental object used by human beings. Shell beads dated from ~75,000 years ago (Pleistocene era) were found in a cave located on South Africa's south coast. Beads made from N. kraussianus shells have also been found in deposits in this region dating from the beginning of the Holocene era (<10,000 years ago). These younger shells were significantly smaller, a phenomenon that has been attributed to a change in human preference. We investigated two alternative hypotheses explaining the difference in shell size: a) N. kraussianus comprises at least two genetic lineages that differ in size; b) the difference in shell size is due to phenotypic plasticity and is a function of environmental conditions. To test these hypotheses, we first reconstructed the species' phylogeographic history, and second, we measured the shell sizes of extant individuals throughout South Africa. Although two genetic lineages were identified, the sharing of haplotypes between these suggests that there is no genetic basis for the size differences. Extant individuals from the cool temperate west coast had significantly larger shells than populations in the remainder of the country, suggesting that N. kraussianus grows to a larger size in colder water. The decrease in fossil shell size from Pleistocene to Holocene was likely due to increased temperatures as a result of climate change at the beginning of the present interglacial period. We hypothesise that the sizes of N. kraussianus fossil shells can therefore serve as indicators of the climatic conditions that were prevalent in a particular region at the time when they were deposited. Moreover, N. kraussianus could serve as a biomonitor to study the impacts of future climate change on coastal biota in southern Africa.
author Teske, Peter R
Papadopoulos, Isabelle
McQuaid, Christopher D
Newman, Brent K
Barker, Nigel P
spellingShingle Teske, Peter R
Papadopoulos, Isabelle
McQuaid, Christopher D
Newman, Brent K
Barker, Nigel P
Climate change, genetics or human choice: why were the shells of mankind’s earliest ornament larger in the Pleistocene than in the Holocene?
author_facet Teske, Peter R
Papadopoulos, Isabelle
McQuaid, Christopher D
Newman, Brent K
Barker, Nigel P
author_sort Teske, Peter R
title Climate change, genetics or human choice: why were the shells of mankind’s earliest ornament larger in the Pleistocene than in the Holocene?
title_short Climate change, genetics or human choice: why were the shells of mankind’s earliest ornament larger in the Pleistocene than in the Holocene?
title_full Climate change, genetics or human choice: why were the shells of mankind’s earliest ornament larger in the Pleistocene than in the Holocene?
title_fullStr Climate change, genetics or human choice: why were the shells of mankind’s earliest ornament larger in the Pleistocene than in the Holocene?
title_full_unstemmed Climate change, genetics or human choice: why were the shells of mankind’s earliest ornament larger in the Pleistocene than in the Holocene?
title_sort climate change, genetics or human choice: why were the shells of mankind’s earliest ornament larger in the pleistocene than in the holocene?
publishDate 2007
url http://hdl.handle.net/10962/d1006001
http://dx.doi.org/10.1371/journal.pone.0000614
work_keys_str_mv AT teskepeterr climatechangegeneticsorhumanchoicewhyweretheshellsofmankindsearliestornamentlargerinthepleistocenethanintheholocene
AT papadopoulosisabelle climatechangegeneticsorhumanchoicewhyweretheshellsofmankindsearliestornamentlargerinthepleistocenethanintheholocene
AT mcquaidchristopherd climatechangegeneticsorhumanchoicewhyweretheshellsofmankindsearliestornamentlargerinthepleistocenethanintheholocene
AT newmanbrentk climatechangegeneticsorhumanchoicewhyweretheshellsofmankindsearliestornamentlargerinthepleistocenethanintheholocene
AT barkernigelp climatechangegeneticsorhumanchoicewhyweretheshellsofmankindsearliestornamentlargerinthepleistocenethanintheholocene
_version_ 1718801377685143552