''Perspicaris'' (from the
Latin
Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through the power of the ...
''perspicax'', meaning “sharp-sighted,” and ''caris'', “crab/shrimp”) an extinct genus of bivalved arthropod from the
Cambrian period. Fossils have been found in North America, primarily the
Burgess Shale
The Burgess Shale is a fossil-bearing deposit exposed in the Canadian Rockies of British Columbia, Canada. It is famous for the exceptional preservation of the soft parts of its fossils. At old (middle Cambrian), it is one of the earliest fo ...
of British Columbia, Canada but also possibly the
Wheeler Shale
The Wheeler Shale (named by Charles Walcott) is a Cambrian ( 507 Ma) fossil locality world-famous
for prolific agnostid and '' Elrathia kingii'' trilobite remains (even though many areas are barren of fossils)
and represents a Konzen ...
,
Marjum Formation
The Marjum Formation is a Cambrian geological formation that overlies the Wheeler Shale in the House Range, Utah. It is known for its occasional preservation of soft-bodied tissue, and is slightly younger than the Burgess Shale
The Burgess S ...
,
Pioche Shale and
Bloomington Formation. Two named species are known from the Burgess Shale ''Perspicaris dictynna'' and ''Perspicaris recondita'', which differ in maximum size ( in ''P. recondita'' vs in ''P. dictynna''), as well as proportions of the tail. Both species have a pair of stalked eyes, as well as a pair of large segmented antennae. The tail is forked and spiny. They are thought to have been active swimmers (
nektonic
Nekton or necton (from the ) refers to the actively swimming aquatic organisms in a body of water. The term was proposed by German biologist Ernst Haeckel to differentiate between the active swimmers in a body of water, and the passive organisms t ...
).
''Perspicaris'' has been identified as a member of a clade
Hymenocarina
Hymenocarina is an order of extinct arthropods known from the Cambrian. They possess bivalved carapaces, typically with exposed posteriors. Members of the group are morphologically diverse and had a variety of ecologies, including as filter feede ...
close to the crown-group of
Euarthropoda
Arthropods (, (gen. ποδός)) are invertebrate animals with an exoskeleton, a segmented body, and paired jointed appendages. Arthropods form the phylum Arthropoda. They are distinguished by their jointed limbs and cuticle made of chitin, oft ...
, which includes myriapods, chelicerates, insects and crustaceans.
References
Burgess Shale fossils
Prehistoric arthropod genera
Wheeler Shale
Fossil taxa described in 1977
{{paleo-arthropod-stub
Hymenocarina