Cowralepis
mclachlani
Phylum
Chordata, Subphylum Vertebrata, Infraphylum Gnathostomata, Class Placodermi,
Order Phyllolepida
Geological
Time: Middle Devonian
Size (25.4
mm = 1 inch): Head and trunk shield: 65 mm in length and 63 mm wide
with 35 mm (curve measure) attached vertebral column and a second 25
mm associated vertebral column on a 170 mm by 110 mm matrix
Fossil Site:
Merriganowry Shale Member, Cowra, New South Wales, Australia
Fossil Code:
AAF551
Price: Sold
Description:
A new taxon of phyllolepid placoderms was described in 2005 as
a result of a study of numerous articulated specimens which were
first discovered in the early 1990s in the crushed shoulder material
for approach roads to the Merriaganowry bridge. The material
was traced to a nearby quarry, uncovering a vast treasure of
specimens of various sizes. Before this time, only 2 sites for
articulated phyllolepids were known in Scotland and Mt Howitt,
Victoria, Australia. Phyllolepids derive their name (meaning “leaf
scale”) from the distinctive ridged ornamentation of the
bony dermal plates. This species was named for the landowner
of the quarry. The fish-bearing sequence is some 25 meters in
thickness, and hundreds of bedding planes containing specimens
are known, the most complete source of articulated specimens
known in the world. Interestingly, this is the sole fish found
in the deposit, with a few pieces of eurypterid integument and
lycopod plant remains and other plant debris the only other fossils
found to date. The head and trunk shield are in a fine state
of preservation with the leaf-like scales and a portion of the
vertebral column in evidence. Note the second vertebral column
at the anterior of the specimen. Based upon the width of this
column, it came from a much smaller example. It either underlays
the main specimen in the opposition direction or was eaten by
the larger example. Based upon the apparent coplanarity I feel
the latter conclusion more likely, making this an example of
what is termed an inspiration in which the smaller fish was consumed
by the larger but ended up choking its predator, giving it the
last laugh.
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