TY - JOUR
T1 - Basal polyphagan beetles in mid-Cretaceous amber from Myanmar
T2 - Biogeographic implications and long-term morphological stasis
AU - Cai, Chenyang
AU - Lawrence, John F.
AU - Yamamoto, Shûhei
AU - Leschen, Richard A.B.
AU - Newton, Alfred F.
AU - Ślipiński, Adam
AU - Yin, Ziwei
AU - Huang, Diying
AU - Engel, Michael S.
PY - 2019/1/16
Y1 - 2019/1/16
N2 - The origin and early evolutionary history of polyphagan beetles have been largely based on evidence from the derived and diverse 'core Polyphaga', whereas little is known about the species-poor basal polyphagan lineages, which include Scirtoidea (Clambidae, Decliniidae, Eucinetidae, and Scirti-dae) and Derodontidae. Here, we report two new species Acalyptomerus thayerae sp. nov. and Sphaerothorax uenoi sp. nov., both belonging to extant genera of Clambidae, from mid-Cretaceous Burmese amber. Acalyptomerus thayerae has a close affinity to A. herbertfranzi, a species currently occurring in Mesoamerica and northern South America. Sphaerothorax uenoi is closely related to extant species of Sphaerothorax, which are usually collected in forests of Nothofagus of Australia, Chile, and New Zealand. The discovery of two Cretaceous species from northern Myanmar indicates that both genera had lengthy evolutionary histories, originated at least by the earliest Cenomanian, and were probably more widespread than at present. Remarkable morphological similarities between fossil and living species suggest that both genera changed little over long periods of geological time. The long-term persistence of similar mesic microhabitats such as leaf litter may account for the 99 Myr morphological stasis in Acalyptomerus and Sphaerothorax. Additionally, the extinct staphylinoid family Ptismidae is proposed as a new synonym of Clambidae, and its only included species Ptisma zasukhae is placed as incertae sedis within Clambidae.
AB - The origin and early evolutionary history of polyphagan beetles have been largely based on evidence from the derived and diverse 'core Polyphaga', whereas little is known about the species-poor basal polyphagan lineages, which include Scirtoidea (Clambidae, Decliniidae, Eucinetidae, and Scirti-dae) and Derodontidae. Here, we report two new species Acalyptomerus thayerae sp. nov. and Sphaerothorax uenoi sp. nov., both belonging to extant genera of Clambidae, from mid-Cretaceous Burmese amber. Acalyptomerus thayerae has a close affinity to A. herbertfranzi, a species currently occurring in Mesoamerica and northern South America. Sphaerothorax uenoi is closely related to extant species of Sphaerothorax, which are usually collected in forests of Nothofagus of Australia, Chile, and New Zealand. The discovery of two Cretaceous species from northern Myanmar indicates that both genera had lengthy evolutionary histories, originated at least by the earliest Cenomanian, and were probably more widespread than at present. Remarkable morphological similarities between fossil and living species suggest that both genera changed little over long periods of geological time. The long-term persistence of similar mesic microhabitats such as leaf litter may account for the 99 Myr morphological stasis in Acalyptomerus and Sphaerothorax. Additionally, the extinct staphylinoid family Ptismidae is proposed as a new synonym of Clambidae, and its only included species Ptisma zasukhae is placed as incertae sedis within Clambidae.
KW - Austral fauna
KW - Bradytely
KW - Clambidae
KW - Nothofagus
KW - Palaeodiversity
UR - http://www.scopus.com/inward/record.url?scp=85061325851&partnerID=8YFLogxK
U2 - 10.1098/rspb.2018.2175
DO - 10.1098/rspb.2018.2175
M3 - Article (Academic Journal)
C2 - 30963875
AN - SCOPUS:85061325851
VL - 286
JO - Proceedings of the Royal Society B: Biological Sciences
JF - Proceedings of the Royal Society B: Biological Sciences
SN - 0962-8452
IS - 1894
M1 - 2175
ER -