Journal article
Paleobiology of Jefferson's Ground Sloth (Megalonyx jeffersonii) derived from three contemporaneous, ontogenetically distinct individuals recovered from Southwestern Iowa, USA
Journal of vertebrate paleontology, Vol.42(1), 2124115
06/30/2022
DOI: 10.1080/02724634.2022.2124115
Abstract
Although known from more than 180 sites in North America, sites with records of multiple Megalonyx elements and individuals are rare. The Tarkio site in southwestern Iowa is unique with three contemporaneous individuals at different stages of development. Among these is one of the largest (ca. 1286 kg) and most complete adult Megalonyx jeffersonii skeletons (ca. 50%, NISP, 123) known. An intermingled sub-adult (ca. 25%, NISP, 63) represents a comparatively complete skeleton for this ontogenetic stage. A third individual, an infant known only from both scapulae (NISP 2), is commingled with sub-adult remains. Scapula sizes indicate that the two juveniles were 50 and 30% of the adult's size. Differential bone preservation and pattern of scatter shows that the adult decomposed lying on its left side and the remains were partially scavenged. Multiple taphonomic proxies demonstrate that the skeletons were subaerially exposed for a limited period, but fluvial transport was not a factor. These individuals, preserved in the same low-energy microstratigraphic unit, apparently died concurrently and probably represent a Megalonyx social unit. Using mammal body size to estimate life history, the estimated average lifespan for M. jeffersonii was around 19 years; gestation time was about 14 months; the interbirth interval was approximately 3 years; and sexual maturation occurred at around 6.5 years. OSL analysis indicates that the sloths were deposited about 106,000 years ago (MIS substage 5ec). Paleoenvironmental proxies suggest an interglacial environment of open woodland along a stream with marshes, like the environment in southwest Iowa today.
Details
- Title: Subtitle
- Paleobiology of Jefferson's Ground Sloth (Megalonyx jeffersonii) derived from three contemporaneous, ontogenetically distinct individuals recovered from Southwestern Iowa, USA
- Creators
- Holmes A. Semken - University of IowaH. Gregory McDonald - 3309 Snowbrush Court, Ft Collins, CO 80521 USARussell W. Graham - Colorado School of MinesTiffany Adrain - University of IowaJoe Alan Artz - University of IowaRichard G. Baker - University of IowaAlexander B. Bryk - University of California, BerkeleyDavid J. Brenzel - Marion Local SchoolsE. Arthur Bettis - University of IowaAndrew A. Clack - McMaster University Medical CentreBrittany L. Grimm - Pennsylvania State UniversityAdel Haj - United States Geological SurveySarah E. Horgen - American Museum of Natural HistoryMeghann C. Mahoney - American Museum of Natural HistoryHarold A. Ray - University of Central MissouriJames L. Theler - University of Wisconsin–La Crosse
- Resource Type
- Journal article
- Publication Details
- Journal of vertebrate paleontology, Vol.42(1), 2124115
- Publisher
- Taylor & Francis
- DOI
- 10.1080/02724634.2022.2124115
- ISSN
- 0272-4634
- eISSN
- 1937-2809
- Number of pages
- 22
- Grant note
- SEGR 0618036; 0829393; EAGAR 1037817 / NSF; National Science Foundation (NSF) Iowa Archeological Society Boy Scouts of America Take A Kid Outdoors Iowa Office of the State Archaeologist Greater Shenandoah Historical Museum Central Iowa Gem and Mineral Society
- Language
- English
- Date published
- 06/30/2022
- Academic Unit
- Earth and Environmental Sciences
- Record Identifier
- 9984516159902771
Metrics
7 Record Views