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Bonde J W. Historical Biology, 2007,
19(2): 203-207
Here we describe a pathological osteoderm
from the crocodylomorph Diplocynodon
hantoniensis (Bouldnor Formation,
earliest Oligocene, Isle of Wight,
United Kingdom). The specimen bears a
porous, erosive branching channel that
distorts the surface ornamentation and
periosteum over 60% of the preserved
dorsal surface area. We diagnose this
condition as necrotizing dermatitis: a
surficial bacterial or fungal infection that
can penetrate the dermal layers to affect
the underlaying penosteum of osteoderms.
This condition has been previously
reported for an extant tortoise
and caiman; however, this is the first reported
occurrence in the fossil record.
2010010048
晚 白 垩 世 Arkhangelskiella 群 的 生 物
统 计 : 由 营 养 流 控 制 的 生 态 表 型 =
Biometry of the Late Cretaceous Arkhangelskiella
group: ecophenotypes controlled
by nutrient flux. ( 英 文 ). Linnert
C; Mutterlose J. Cretaceous Research,
2009, 30(5): 1193-1204 1 图 版 .
This study focuses on the morphometry
and taxonomy of the Late Cretaceous
coccolith genus Arkhangelskiella. Sixty
samples from the Campanian–
Maastrichtian interval of DSDP Hole
390A (Blake Nose) were investigated
for their contents of Arkhangelskiella
spp. In each sample one hundred specimens
of Arkhangelskiella spp. were examined
by measuring the coccolith
length and width, as well as the length
and width of the central area. In the
samples investigated the Arkhangelskiella
group exhibits a large size variation,
specimens length varies from
4.95 μm to 14.52 μm. Former taxonomic
concepts, based on morphometry, subdivided
the Arkhangelskiella group into
three species: Arkhangelskiella maastrichtiana,
Arkhangelskiella confusa and
Arkhangelskiella cymbiformis. Our data
show a large variability of the morphometric
data (coccolith length, width
of the outer rim). There is no indication
for three independant species; two of the
quoted taxa (1. thick outer
rim = Arkhangelskiella maastrichtiana;
2. very thin outer
rim = Arkkhangelskiella cymbiformis)
seem to be extreme forms of a continuous
morphometric lineage. The lower
part of the investigated succession
(139.92–133.42 mbsf) is dominated by
small specimens with an average length
of 6.8 μm whereas the upper part
(132.86–126.15 mbsf) is characterized
by larger specimens (mean 8.7 μm). In
DSDP Hole 390A the size increase appears
to be very abrupt, within two samples
(samples 133.42 mbsf, 132.86 mbsf)
the mean size increases by 1.51 μm.
Previous morphometric studies of Arkhangelskiella
indicate a more continuous
size increase throughout the late Campanian–Maastrichtian.
The abrupt size
increase observed here hints toward a
minor hiatus in DSDP Hole 390A separating
upper Campanian from lower
Maastrichtian sediments. It seems likely
that the size increase of Arkhangelskiella
reflects changes of various environmental
factors like nutrient supply and
sea water chemistry (Mg/Ca ratio; Ca
concentration). A comparison of morphometric
results with previous palaeoecological
studies documents a nutrient
control for the growth of Arkhangelskiella.
Small specimens can be
related to more mesotrophic conditions
whereas large specimens are linked to
oligotrophic surface waters.
2010010049
保 存 在 古 代 叶 甲 虫 中 的 原 始 结 构 颜 色
= Original structural color preserved in
an ancient leaf beetle. ( 英 文 ). Tanaka G;
Taniguchi H; Maeda H; Nomura S. Geology,
2010, 38(2): 127-130
Greenish-blue metallic colored fossil
elytra of the leaf beetle (Plateumaris sp.)
have been discovered in the peat sediment
of the middle Pleistocene (ca. 600
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