Mecochirus
longimanu Subphylum
Crustacea, Class Malacostraca, Order Decapoda, Superfamily Glypheoidea
Geological
Time: Upper Jurassic
Size: 197
mm
Fossil
Site: Solnhofen Limestone, Eichstatt, Germany "Plattenkalk” Malm Zeta 2, Eichstatt, Germany
| Description:
This is an unusual member of the lobster family, with elongated
first pair of walking legs that are most distinctive, and are the
derivation species name logimanu (meaning long arm). In most specimens
these long arms are poorly preserved. Not so in this specimen, as
they are well preserved.
As
their name implies, all decapods have ten legs; these are the last
five of the eight pairs of thoracic appendages characteristic of
crustaceans. The front three pairs function as mouthparts and are
generally referred to as maxillipeds, the remainder being pereiopods.
In many decapods, however, one pair of legs has enlarged pincers;
the claws are called chelae, so those legs may be called chelipeds.
Further appendages are found on the abdomen, with each segment capable
of carrying a pair of biramous pleopods, the last of which form
part of the tail fan (together with the telson) and are called uropods.
This fossil comes from the lithographic limestone Solnhofen deposits
of Germany, and world class Lagerstätte.
These 150 million year old deposits are famous for their exceptionally
well-preserved organisms, the most famous of which are the handful
of specimens of the ancient bird Archaeopteryx.
Also
see: Solnhofen Fossils
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