Title page for ETD etd-07102009-110514

Type of Document Master's Thesis
Author Pharr, Lauren Rebecca
Author's Email Address Laurenpharr@gmail.com
URN etd-07102009-110514
Title A Taphonomic Model of Concealment: Decomposition and the Postmortem Interval (PMI) in a 55-Gallon Barrel
Degree Master of Arts (M.A.)
Department Geography & Anthropology
Advisory Committee
Advisor Name Title
Manhein, Mary H Committee Chair
Kramer, Wayne L Committee Member
Mann, Robbie B Committee Member
Richardson, Miles Edward Committee Member
  • Carrion
  • Mummification
  • Liquefied remains
  • Adipocere
  • Diptera larval development
  • Louisiana
  • Chrysomya megacephala
  • Cochliomyia macellaria
  • Blow fly (Calliphoridae)
  • Forensic anthropology
  • Forensic entomology
  • Taphonomy
  • Postmortem interval
  • Decomposition
  • Concealed remains
  • Lucilia coeruleiviridis
  • Chrysomya rufifacies
  • Phormia regina
  • Lucilia eximia
  • Lucilia cuprina
  • Red Imported Fire Ant (Solenopsis invicta)
Date of Defense 2009-07-02
Availability unrestricted
Three 80-pound pigs used as human models were sealed inside 55-gallon black metal drums to monitor the rates and stages of decomposition of concealed, child-sized remains. Visual assessments of the anaerobic decomposition processes in each of the drums for Pigs A and B were possible through a Lexan window installed on each drums’ lid. The third pig—Pig C—was placed inside a drum with four one-half-inch holes permitting insect access and oriented in north, south, east, and west positions around the drum’s upper perimeter. Visual assessments of Pig C were made by lifting the drum’s lid; these assessments revealed that the maggots inside were capable of surviving the intense Louisiana heat by moving in unison in the opposite direction of the sun. As expected, Pig C decomposed to a skeleton at an accelerated rate, while the liquefied remains in the barrel continued a series of dramatic changes over a six-month period.

After 33 days, the lid was removed from Barrel B and blow flies immediately flocked to the recently unsealed drum. Despite the blow flies’ ability to colonize Pig B, the decompositional changes witnessed for Pig C were not seen. Pig A remained sealed in its barrel and stages of decomposition in an airtight container were assessed. All three pigs were monitored daily for six months. The only similarity in decomposition observed among Pigs A, B, and C was intestinal expulsion, which involved the intact organs resting on top of each pig outside the body.

Additionally, when Barrel B was opened, two fetal pigs were placed on the ground to compare their faunal succession to that of Pig B. Insects associated with the barrel pigs and the fetal pigs were collected and identified. Chrysomya megacephala was documented, collected, and recorded as being established in Louisiana for the first time. Cochliomyia macellaria was the predominant species overall.

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