title: Archaeological bone lipids as palaeodietary markers.
abstract: BACKGROUND
  Stable isotope analysis of archaeological and fossil bone samples can provide important insights into past environments, ecologies and diets. Previous studies have focused on stable carbon and nitrogen isotopes in bone collagen, or carbon isotopes in bone mineral (bioapatite). Carbon isotope analysis of lipids from archaeological bone has received much less attention, partly due to the lack of suitable methodologies allowing sufficient recovery of compounds for structural and isotopic characterisation. Here we show that lipids can be easily and reliably recovered from archaeological bone using a modified protocol, and that these provide complementary dietary information to other bone components.
  
  
  METHODS
  Human and animal bones were obtained from a variety of archaeological contexts. Lipids were sequentially extracted using solvent extraction (dichloromethane/methanol), followed by acidified methanol extraction (methanol/H2SO4). The lipids were then analysed by gas chromatography/mass spectrometry (GC/MS) and gas chromatography/combustion/isotope ratio mass spectrometry (GC/C/IRMS).
  
  
  RESULTS
  Appreciable amounts of endogenous lipid were recovered from archaeological bone. Importantly, a comparison between compound-specific and bulk collagen isotopic data shows that archaeological bone lipids reflect dietary input and can be used to distinguish between marine and terrestrial consumers, as well as between C3 and C4 plant consumers. Furthermore, the presence of essential fatty acids directly incorporated from diet to bone may provide additional palaeodietary information.
  
  
  CONCLUSIONS
  Our findings suggest that archaeological bone lipids are a hitherto untapped resource of dietary information that offer additional insights to those gained from other isotopic analyses of bone.
authors.affiliation: BioArCh, University of York, Biology S-Block, Wentworth Way, York, YO10 5DD, UK.
authors.forename: André C
authors.identifier: http://orcid.org/0000-0002-0279-6634
authors.initials: AC
authors.lastname: Colonese
authors.affiliation: BioArCh, University of York, Biology S-Block, Wentworth Way, York, YO10 5DD, UK.|Arctic Centre, University of Groningen, PO Box 716, 9700, AS, Groningen, The Netherlands.
authors.forename: Thomas
authors.initials: T
authors.lastname: Farrell
authors.affiliation: BioArCh, University of York, Biology S-Block, Wentworth Way, York, YO10 5DD, UK.
authors.forename: Alexandre
authors.initials: A
authors.lastname: Lucquin
authors.affiliation: BioArCh, University of York, Biology S-Block, Wentworth Way, York, YO10 5DD, UK.
authors.forename: Daniel
authors.initials: D
authors.lastname: Firth
authors.affiliation: BioArCh, University of York, Biology S-Block, Wentworth Way, York, YO10 5DD, UK.
authors.forename: Sophy
authors.initials: S
authors.lastname: Charlton
authors.affiliation: BioArCh, University of York, Biology S-Block, Wentworth Way, York, YO10 5DD, UK.
authors.forename: Harry K
authors.initials: HK
authors.lastname: Robson
authors.affiliation: BioArCh, University of York, Biology S-Block, Wentworth Way, York, YO10 5DD, UK.
authors.forename: Michelle
authors.initials: M
authors.lastname: Alexander
authors.affiliation: BioArCh, University of York, Biology S-Block, Wentworth Way, York, YO10 5DD, UK.
authors.forename: Oliver E
authors.initials: OE
authors.lastname: Craig
mesh_terms: D000818:Animals; D001106:Archaeology / Q000379:methods*; D015415:Biomarkers / Q000032:analysis* / Q000737:chemistry; D001842:Bone and Bones / Q000737:chemistry*; D002247:Carbon Isotopes / Q000032:analysis; D003094:Collagen / Q000737:chemistry; D004032:Diet / Q000266:history / Q000662:veterinary; D008401:Gas Chromatography-Mass Spectrometry; D049690:History, Ancient; D006801:Humans; D008055:Lipids / Q000032:analysis* / Q000737:chemistry; D009587:Nitrogen Isotopes / Q000032:analysis; D010163:Paleontology / Q000379:methods*
chemical_list: D015415:Biomarkers; D002247:Carbon Isotopes; D008055:Lipids; D009587:Nitrogen Isotopes; D003094:Collagen