[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]

Pre-mammalian hair in Permian coprolites + Triassic impact evidence from Japan



Ben Creisler
bcreisler@gmail.com

Two non-dino papers that may be of interest:

Piotr Bajdek, Martin Qvarnström, Krzysztof Owocki, Tomasz Sulej,
Andrey G. Sennikov, Valeriy K. Golubev and Grzegorz Niedźwiedzki
(2015)
Microbiota and food residues including possible evidence of
pre-mammalian hair in Upper Permian coprolites from Russia.
Lethaia (advance online publication)
DOI: 10.1111/let.12156
http://onlinelibrary.wiley.com/doi/10.1111/let.12156/abstract


Coprolites (fossil faeces) provide direct evidence on the diet of its
producer and unique insights on ancient food webs and ecosystems. We
describe the contents of seven coprolites, collected from the Late
Permian Vyazniki site of the European part of Russia. Two coprolite
morphotypes (A, B) contain remains of putative bacteria,
cyanobacteria, fungi, protists, invertebrate eggs, arthropod elements,
undigested bone and tooth fragments, fish scales and elongated
hair-like structures with hollow interiors. Content, size and shape of
the coprolites together with the associated body fossil record suggest
that the most probable scat-producers were carnivorous tetrapods; the
bone-rich morphotype A reveals short food retention time and a fast
metabolism and is therefore assigned to therapsid carnivores whereas
morphotype B with rarer and degraded bones are assigned to
archosauromorphs or other non-therapsid carnivores. The general
coprolite matrix contains abundant micron-sized spheres and
thin-walled vesicles which are interpreted as oxide and phosphatic
pseudomorphs after microbial cells. From analyses of the undigested
bones, we infer that they represent remains of actinopterygian fish, a
therapsid and unrecognizable parts of amphibians and/or reptiles.
Additionally, hair-like structures found in one coprolite specimen
occur as diagenetically altered (oxide-replaced) structures and moulds
(or partly as pseudomorphs) in a microcrystalline
carbonate-fluoride-bearing calcium phosphate. This suggests that the
latest Permian therapsids probably were equipped with hair-like
integument or hairsuit. If true, this is by far the oldest evidence of
this mammalian character in the stem group of mammals.

==

Honami Sato, Naoki Shirai, Mitsuru Ebihara, Tetsuji Onoue & Shoichi
Kiyokawa (2015)
Sedimentary PGE signatures in the Late Triassic ejecta deposits from
Japan: implications for the identification of impactor.
Palaeogeography, Palaeoclimatology, Palaeoecology (advance online publication)
doi:10.1016/j.palaeo.2015.11.015
http://www.sciencedirect.com/science/article/pii/S0031018215006719

Highlights
Impact ejecta layers were discovered in Late Triassic deep-sea
deposits from Japan.
PGE abundances were determined in the Late Triassic impact ejecta layers.
We show that the impactor was 3.3–7.8 km diameter chondritic impactor.
The amount of climatically active sulfur released from the impactor is
estimated.

Abstract
Positive platinum group element (PGE) concentration and negative Os
isotope anomalies reported from a claystone layer in the Upper
Triassic bedded chert succession of the Sakahogi section, Mino Belt,
central Japan, are thought to have been derived from an impact event.
Stratigraphic variations and concentrations of PGE were examined in
the Sakahogi section to determine the type of the impactor. Upper
Triassic claystone layers, where PGE anomalies have been newly
discovered in bedded chert successions in southwest Japan, were also
examined. These include (i) the Unuma section in the Inuyama area,
Mino Belt; (ii) the Hisuikyo section in the Kamiaso area, Mino Belt;
and (iii) the Enoura section in the Tsukumi area, Chichibu Belt.
Radiolarian and conodont biostratigraphic data indicates that these
claystone layers are of upper middle Norian age. Reconstruction of
bedded chert in these sections suggests that they originate from
open-ocean pelagic deep-sea sediments deposited in the Panthalassa
Ocean.

The relatively flat CI-chondrite normalized patterns of the least
mobile PGEs (Ir, Ru, and Rh) and the Ru/Ir ratio determined by linear
regression analysis suggest that a chondritic impactor is the source
of the PGE anomalies preserved in claystone samples from the study
sections. Although Ru/Ir ratios cannot conclusively distinguish
chondrites from iron meteorites, the Cr/Ir ratios of the claystone
layers range from 104 to 105, clearly indicating contribution from
chondritic materials. The chondritic impactor of the suggested size
(3.3–7.8 km in diameter) implies that a large amount of debris and/or
climatically active gasses (e.g., sulfur oxides) would have been
released from the impactor, which would have had a marked effect on
the environment.