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Australia: The Land Where Time Began |
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Precambrian-Cambrian Boundary Interval – Occurrence and Form of
Shaanxilithes ningqiangensis,
an Enigmatic Body Fossil from the Lesser Himalaya, India
Shaanxilithes
ningqiangensis,
a fossil from the Ediacaran, and putatively related forms, have long
been regarded as enigmatic; interpretations have been put forward over
the past few decades that range from trace fossils, algae, to metazoans
of uncertain phylogenetic placement. In this paper Tarhan et
al. have presented combined
morphological and geochemical evidence from a new occurrence of
S. ningqiangensis in the
Krol and Tal Groups of the Lesser Himalaya, India, that indicates that
it is not a trace fossil, rather it is a tubular body fossil with an
organic wall, but its taxonomic affinity is not known. Tarhan et
al. say specimens consist of
organic cylindrical structures that have been compressed, that are
characterised by extended, overlapping or fragmented iterated units.
Rather than branching or intraplanar crossing, overlapping is observed
where specimens intersect. An age of Late Ediacaran for the uppermost
Krol Group and basal Tal Group have been suggested by lithologic
comparisons and sequence stratigraphic data. This new occurrence of
S. ningqiangensis has
expanded the biostratigraphical utility of this fossil to the
inter-regional and intercontinental scale by extending the
biogeographical distribution of
S. ningqiangensis, that
had hitherto been confined to
Ediacaran deposits
in China, and potentially Siberia, to the
Precambrian-Cambrian
boundary interval in India. Tarhan et
al. suggest that study of
these new, exceptionally preserved samples may help to significantly
constrain the affinity of
Shaanxilithes, that has
been debated for a long time, and elucidate its ‘problematic’ status and
shed new light on the ecology and taphonomy of an interval of time that
is one of the most significant intervals in the history of life on
Earth.
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Author: M.H.Monroe Email: admin@austhrutime.com Sources & Further reading |