Invertebrates: Insects and Molluscs Flashcards
Archaeomalacology
Study of the remains of molluscs in the archaeological record
Identification of Molluscs
- Soft unsegmented body and CaCo3 exoskeleton
- Not all have shells (slugs)
8 different mollusc orders in the mollusc class
Domain - Kingdom - Phylum - Class - Order - Family - Genus - Species
- Aim to identify down to the species level
- Terrestrial molluscs: often only identify to family or at most genus
- Freshwater shells: identify to genus and species
- Phylum Mollusca: grouped by morphology and behaviour into classes and sub-classes
- Over 160,000 known species
Mollucs of most interest
- Gastropoda and Bivalvia
- More likely to come across on archaeological sites
- Most other molluscs don’t have exoskeletons or internal components that survive
Recovery and identification of molluscs
- Most shells will be hand collected during species excavation
- Smaller shells may be recovered through floatation
- Recorded as small finds
- Wet sieving
When might shell preservation be limited
In acidic environments
Why might it be hard to identify terrestrial gastropods down to species level
Species specific traits often in soft tissues
What should be considered when using shell remains to reconstruct past cultural/social activities and environments
- First: consider biostatinomy, all processes that affect the assemblage after organism death
- What agent was responsible for shell accumulation? cultural vs natural
- Actions of sea birds are problematic: create large species-selective, highly fragmented shell assemblages
- Storms, tsunamis, floods
Human use of shells
- Analogues are drawn from records of recent or historically documented group
- Among non-industrial groups, shell adornments often convey social information, including group affiliation
- Ethnographic record suggests 4 main uses: food, fish bait, raw material, currency
Shell as raw material
- Commonly used for fishhooks and lures in traditional fisheries
- Fish familiar with appearence and smell
- Bivalves exploited for sharp cutting edges
- Large species used as vessels, spoons, trumpets
- Shell beads and personal adornments
- Nacreous interior surface or decorative exterior
- Unusual shape, texture, or rarity
Shellfish as food, historically
- In historic times, shellfish were often exploited during times of scarcity and prized in communities for creating variety in diet
- Shell fishing undertaken by women and children, less prestigious than hunting
- Predicatble resource and source of protein
Insect remains: class insecta species classification
Domain - Kingdom - Phylum - Class - Order - Family - Genus - Species
- Most abundant animal class, approx 75% of all extant species
- Over 1 million species
- Grouped by morophology and behaviour into sub classes
- Focu on beetles and flies, most commonly encountered in archaeology
Palaeoentomology
look at insects remains to reconstruct past environments
Archaeoentomology
Look at insect remains to reconstruct human behaviour
Preservation of insect remain
- Exoskeleton made of chitin
- Polysaccharide
- Chemically inert
- Extremely durable
Best preserved in:
- Permanently wet conditions
- Permenantly dry conditions
- Acidic to neutral pH
- E.g. peat bogs, lakes, rivers, clays, permafost
- Abdomen mot often found, potentially wing cases, head is wanted for identification but not always the best preserved component
Recovery of insect remains
- Most will be recovered with floatation tanks
- Less dense materials float to the water surface
- Float residues are collected in a small meshed sieve
- Paraffin floatation is the most widely used technique
- Remains should be preserved in ethanol
Why are insects of interest to archaeologists
- Specialists are of particular interest, they are species that inhabit specific ecological niches
- Synathropic species that reflect human habitats/activities
- Grain weevils only inhabit human food stores
- Implicit assumption: ecological niche preference/tolerance remains constant over time
- Assumung contemporary species behaviours are the same as the past
Synathropic species
- 5000+ species
- Human ectoparasites: 3 species of Pthiraptera are synanthropic
- Indicators of sanitary conditions
Lice as synanthropic species
- Indicate the timing of the first use of clothing
- Genetic age of body lice vs head lice
- Body lice evolved from head lice
- They needed shelter, needed fitted clothing to survive
- Species split 100-700,000 years ago
- Lice have a relatively soft bodt and are only preserved under exceptional conditions
- Knit combs today look the same as Egyptian coptic bone combs
Pathogen vectors:
- Trench fever
- Typhus
- Trench fever:
- Recurrent high fever, severe headaches, rash
- Typhus:
- High fever, severe headaches, rash, vomiting, diarrhoea, gangrene, organ failure
