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siliciclastic sediments compared to
dominantly carbonate sediments. The
most important factors limiting the
postmortem persistence of shell material
are (1) exposure above the sedimentwater
interface, which is enhanced in
coarser-grained carbonate sediments and
permits attack by bioeroders and encrusters;
(2) the availability of abundant
reactive iron mineral phases in the sediments,
which promotes supersaturated
pore waters and limits acid production;
and (3) shell microstructure (rather than
mineralogy), particularly organic content
that is the focus of intense microbial
attack. Thus, there is significant potential
for enhanced carbonate shell preservation
in areas receiving ferric-rich
tropical weathering products, which are
common in much of the tropics today
and are associated with subduction systems
in the geologic past. This suggests
that paleodiversity estimates from carbonate
tropical settings are minima and
that siliciclastic settings are probably
underestimated regions for carbon burial,
given the large proportion of tropical
shelf area characterized by such conditions
and the relatively high proportional
capture there of local carbonate production
2010010223
泰 国 东 部 中 二 叠 统 瓜 德 鲁 普 世 稀 有 的
似 蜓 螺 型 腹 足 类 Magnicapitatus 属 一
新 种 = A new species of the rare neritopsid
gastropod Magnicapitatus from
the Guadalupian (Middle Permian) of
East Thailand (the Indochina Terrane).
( 英 文 ). Sone M. Alcheringa, 2010, 34(1):
1 - 6
A new species of the rare neritopsid
gastropod genus Magnicapitatus is
documented from a fusulinoid-rich limestone
of the Khao Taa Ngog Formation
(Capitanian, Middle Permian) at Khao
Makha in East Thailand near the Cambodian
border (in the Indochina Terrane).
This represents the first record of this
Permo-Triassic genus outside South
China and from the Capitanian. Magnicapitatus
is one of the typical molluscan
Lazarus taxa that apparently disappeared
at the end of the Permian but reappeared
after the Early Triassic.
2010010224
腹 足 类 证 据 不 支 持 早 三 叠 世 小 型 化 效
应 假 说 = Gastropod evidence against
the Early Triassic Lilliput effect. ( 英 文 ).
Brayard A; Nützel A; Stephen D; Bylund
K G; Jenks J; Bucher H. Geology,
2010, 38(2): 147-150
Size reduction in the aftermath of the
Permian-Triassic mass extinction event
has repeatedly been described for various
marine organisms, including gastropods
(the Lilliput effect). A Smithian
gastropod assemblage from Utah, USA,
reveals numerous large-sized specimens
of different genera as high as 70 mm, the
largest ever reported from the Early Triassic.
Other gastropods reported from
Serbia and Italy are also as large as 35
mm. Size frequency distributions of the
studied assemblages indicate that they
were not unusually small when compared
with later Mesozoic and modern
faunas. The occurrence of large-sized
gastropods less than 2 Ma after the Permian-Triassic
mass extinction refutes the
Lilliput hypothesis in this clade, at least
for the last 75% of the Early Triassic
2010010225
伏 尔 加 河 中 下 游 地 区 由 P.A. Gerasimov
采 集 的 早 白 垩 世 腹 足 类 = Early
Cretaceous gastropods of the Middle-
Lower Volga river region from P.A.
Gerasimov’s collection. ( 英 文 ). Golovinova
M A; Guzhov A V. Paleontological
Journal, 2009, 43(5): 506-513 2 图
版 .
Based on the studying of gastropods
collected by P.A. Gerasimov from the
Cretaceous beds of the Volga region,
four new species are established: Avellana
hauteriviensis sp. nov. from the
Upper Hauterivian of the Ulyanovsk re-
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