TY - JOUR
T1 - A new leanchoiliid megacheiran arthropod from the lower Cambrian Emu Bay Shale, South Australia
AU - Edgecombe, Gregory D.
AU - García-Bellido, Diego C.
AU - Paterson, John R.
PY - 2011/6
Y1 - 2011/6
N2 - The Leanchoiliidae is well-known from abundant material of Leanchoilia, from the Burgess Shale and Chengjiang Konservat-Lagerstätten. The first Australian member of the group is Oestokerkus megacholix gen. et sp. nov., described from the Emu Bay Shale (Cambrian Series 2, Stage 4), at Buck Quarry, Kangaroo Island, South Australia, and is intermediate in age between the well known leanchoiliid species from the Burgess Shale and Chengjiang. Phylogenetic analysis of "short great appendage" arthropods (Megacheira) in the context of the chelicerate stem group resolves the Australian species as sister to Burgess Shale, Utah, and Chengjiang Leanchoilia species, but most readily distinguished from Leanchoilia and Alalcomenaeus by a different telson shape, interpreted as being forked, widening distally, and with a few dorsally curved spines at the posterior angle. Leanchoiliid interrelationships are stable to alternative character weights, and Megacheira corresponds to a clade in most analyses.
AB - The Leanchoiliidae is well-known from abundant material of Leanchoilia, from the Burgess Shale and Chengjiang Konservat-Lagerstätten. The first Australian member of the group is Oestokerkus megacholix gen. et sp. nov., described from the Emu Bay Shale (Cambrian Series 2, Stage 4), at Buck Quarry, Kangaroo Island, South Australia, and is intermediate in age between the well known leanchoiliid species from the Burgess Shale and Chengjiang. Phylogenetic analysis of "short great appendage" arthropods (Megacheira) in the context of the chelicerate stem group resolves the Australian species as sister to Burgess Shale, Utah, and Chengjiang Leanchoilia species, but most readily distinguished from Leanchoilia and Alalcomenaeus by a different telson shape, interpreted as being forked, widening distally, and with a few dorsally curved spines at the posterior angle. Leanchoiliid interrelationships are stable to alternative character weights, and Megacheira corresponds to a clade in most analyses.
KW - Alalcomenaeus
KW - Arthropoda
KW - Cambrian
KW - Leanchoilia
KW - Leanchoiliidae
KW - Megacheira
KW - midgut glands
KW - Oestokerkus
KW - phylogeny
KW - South Australia
UR - http://www.scopus.com/inward/record.url?scp=79959582197&partnerID=8YFLogxK
U2 - 10.4202/app.2010.0080
DO - 10.4202/app.2010.0080
M3 - Article
AN - SCOPUS:79959582197
SN - 0567-7920
VL - 56
SP - 385
EP - 400
JO - Acta Palaeontologica Polonica
JF - Acta Palaeontologica Polonica
IS - 2
ER -