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New Gobiconodon species from Lower Cretaceous of China + Lower Cretaceous mammals from Japan

Ben Creisler

New Mesozoic mammals in special issue of Historical Biology:

Nao Kusuhashi, Yuan-Qing Wang, Chuan-Kui Li & Xun Jin (2016)
Two new species of Gobiconodon (Mammalia, Eutriconodonta,
Gobiconodontidae) from the Lower Cretaceous Shahai and Fuxin
formations, northeastern China
Historical Biology 28(1-2): 14-26
Special Issue:   Contributions to vertebrate palaeontology in honour
of Yukimitsu Tomida

Two new gobiconodontid mammals, Gobiconodon tomidai sp. nov. and
Gobiconodon haizhouensis sp. nov., from the Lower Cretaceous (Aptian
to Albian) Shahai and Fuxin Formations, respectively, in Liaoning
Province, northeastern China, are described. Gobiconodon tomidai sp.
nov. is a small-sized species of the genus characterised by the lower
dental formula, a double-rooted p2, the molariform crown being
mesiodistally longer than tall, and a distinct and almost continuous
lingual cingulid on m2–m4. Gobiconodon haizhouensis sp. nov. is of
similar size to Gobiconodon tomidai sp. nov. and is characterised by
the lower dental formula, the molariform crown being slightly
taller than the mesiodistal length, and a well-developed and almost
continuous lingual cingulid on m1–m3. The new materials indicate that
the upper molariform count of most species of Gobiconodon is likely to
be four, one less than the lower molariform count. Gobiconodon is the
second mammalian genus common to the Jehol and Fuxin mammalian faunas.


Kazunori Miyata, Yoichi Azuma & Masateru Shibata (2016)
New mammalian specimens from the Lower Cretaceous Kitadani Formation,
Tetori Group, Fukui, Japan.
Historical Biology 28(1-2): 139-150
Special Issue:   Contributions to vertebrate palaeontology in honour
of Yukimitsu Tomida

New specimens of two non-therian (non-tribosphenidan) mammals are
described from the Lower Cretaceous Kitadani Formation in the upper
part of the Tetori Group, Katsuyama, Fukui Prefecture, Japan. Despite
their poor preservation, these specimens represent undescribed species
from Japan, suggesting additional mammalian diversity in the Tetori
Group. Previously, four mammal taxa had been formally described from
this rock unit: a spalacotheriid ‘symmetrodont’, two eobaatarid
multituberculates and a eutriconodont mammal. One of the new specimens
is a damaged left p4 of a ‘plagiaulacidan’ grade multituberculate
assignable to the family Eobaataridae. The Kitadani eobaatarid is a
large species distinguished from the two previously described
eobaatarids, Tedoribaatar and Hakusanobaatar, which are known from the
stratigraphically lower Kuwajima Formation of the Tetori Group,
Hakusan, Ishikawa Prefecture, Japan. It also differs from Sinobaatar,
Heishanobaatar and Liaobaatar described from the Early Cretaceous of
China. Another specimen, a partial right dentary with a faint
Meckelian groove, is assigned to a eutriconodontan that is larger than
and morphologically distinguishable from the eutriconodont Hakusanodon
from the Kuwajima Formation. The Kitadani eutriconodontan is
potentially related to the family Triconodontidae. The additional
specimens from the Kitadani Formation shed new light on Early
Cretaceous mammalian faunal change and dispersal in East Asia.