TY - JOUR
T1 - Walking on ashes
T2 - insect trace fossils from Laetoli indicate poor grass cover associated with early hominin environments
AU - Genise, Jorge F.
AU - Harrison, Terry
N1 - Funding Information:
Acknowledgements. The authors thank Betty Roberto for hours of assistance with labels, bags and ordering during the work of JFG; Margarita Romero Miranda for taking measurements of almost 3000 specimens of Fictovichnus gobiensis; Baraka Mtallo and Moses Baynet, the guides at Tarangire and Serengeti National Parks in Tanzania respectively, for their useful insights on dung beetle biology; Amandus Kweka and Audax Mabulla for their assistance in the National Museum of Tanzania. We thank Dino Martins for sharing his expertise on East African bees. We also thank the Tanzania Commission for Science and Technology and the Tanzania Antiquities Department for granting permission to conduct research at Laetoli and at the National Museum at Dar es Salaam. This research was supported by NSF Grant BCS-1350023 to TH. Alfred Uchman, one anonymous reviewer, Duncan McIlroy and Sally Thomas improved the original manuscript.
Publisher Copyright:
© The Palaeontological Association
PY - 2018/7
Y1 - 2018/7
N2 - More than 4000 insect trace fossils collected in recent years from Pliocene deposits at Laetoli in northern Tanzania provide new insights on early hominin palaeoenvironments. These trace fossils include: Fictovichnus gobiensis, Coprinisphaera murguiai, C. kheprii, Coprinisphaera ispp., Quirogaichnus isp., Teisseirei linguatus isp. nov., Celliforma ritchiei isp. nov., C. spirifer, C. germanica, C. cfr. curvata, Celliforma ispp., Rosellichnus isp., Vondrichnus planoglobus, Laetolichnus kwekai igen. et isp. nov. and Krausichnidae indet. They reveal that at least one species of moth, three dung beetles and five other coleopterans, nine taxa of solitary bees, and an indeterminate number of taxa of termites inhabited the Lower Laetolil environments. The Upper Laetolil environments, which have yielded a rich diversity of vertebrate fossils, including the early hominin Australopithecus afarensis and its putative footprints, supported several taxa of termites, one dung beetle, five other coleopterans, and eleven taxa of bees. The Upper Ndolanya environments, which have yielded the hominin Paranthropus aethiopicus, record four taxa of dung beetles, four other coleopterans, and two taxa of bees. The record of larval mortality and lack of intruder activity, revealed by the absence of emergence and intruder traces, may be associated with the anoxic/hypoxic conditions caused by the instantaneous burial of soils under thick volcanic ashes. The record of the Celliforma Ichnofacies in the Upper Laetolil environments indicates the dominance of shrubland to woodland with limited grass cover. This is supported also by the absence of Coprinisphaera, which suggests a scarcity of fresh grasses and a low abundance of large mammal grazers.
AB - More than 4000 insect trace fossils collected in recent years from Pliocene deposits at Laetoli in northern Tanzania provide new insights on early hominin palaeoenvironments. These trace fossils include: Fictovichnus gobiensis, Coprinisphaera murguiai, C. kheprii, Coprinisphaera ispp., Quirogaichnus isp., Teisseirei linguatus isp. nov., Celliforma ritchiei isp. nov., C. spirifer, C. germanica, C. cfr. curvata, Celliforma ispp., Rosellichnus isp., Vondrichnus planoglobus, Laetolichnus kwekai igen. et isp. nov. and Krausichnidae indet. They reveal that at least one species of moth, three dung beetles and five other coleopterans, nine taxa of solitary bees, and an indeterminate number of taxa of termites inhabited the Lower Laetolil environments. The Upper Laetolil environments, which have yielded a rich diversity of vertebrate fossils, including the early hominin Australopithecus afarensis and its putative footprints, supported several taxa of termites, one dung beetle, five other coleopterans, and eleven taxa of bees. The Upper Ndolanya environments, which have yielded the hominin Paranthropus aethiopicus, record four taxa of dung beetles, four other coleopterans, and two taxa of bees. The record of larval mortality and lack of intruder activity, revealed by the absence of emergence and intruder traces, may be associated with the anoxic/hypoxic conditions caused by the instantaneous burial of soils under thick volcanic ashes. The record of the Celliforma Ichnofacies in the Upper Laetolil environments indicates the dominance of shrubland to woodland with limited grass cover. This is supported also by the absence of Coprinisphaera, which suggests a scarcity of fresh grasses and a low abundance of large mammal grazers.
KW - Celliforma Ichnofacies
KW - Laetoli
KW - early hominin environments
KW - grass cover
KW - insect trace fossils
UR - http://www.scopus.com/inward/record.url?scp=85044330055&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85044330055&partnerID=8YFLogxK
U2 - 10.1111/pala.12357
DO - 10.1111/pala.12357
M3 - Article
AN - SCOPUS:85044330055
VL - 61
SP - 597
EP - 624
JO - Palaeontology
JF - Palaeontology
SN - 0031-0239
IS - 4
ER -