Trilobite - Asaphus Raniceps
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ITEM# TRILO-Russia-0020
$250.00
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$200.00
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Lower Ordovician - 480 mya
Lava River, Kunda Level
St. Petersburg region
ITEM# TRILO-Russia-0020
This is a well-inflated and museum-quality example of the rare and impressive asaphid trilobite Asaphus raniceps from the Lower Ordovician deposits near St. Petersburg, Russia. Asaphus raniceps is a member of the Order Asaphida, Family Asaphidae. Asaphus raniceps is one of the 35 species of trilobite of the genus Asaphus. This taxon was a stem trilobite that ultimately led to Asapahus ornatus, the last survivor of the genus.
Sometime during the Ordovician period, an inland sea formed in what is now Eastern Europe. The sea contained a remarkably diverse trilobite fauna. Over a dozen species of Asaphus developed in this sea, with many species, including unrelated species, developing long eyestalks (officially called "peduncles") in various lengths. That so many species of trilobite developed eyestalks suggests that they were trying to overcome increased turbidity, or there was some sort of massive selective pressure leading these trilobites to bury themselves in the substrate up to their eyes. This species may have lain in wait buried in a benthic layer of loose debris or sediment with only its periscope eyestalks protruding above, looking out for danger or prey. Asaphida is a large, morphologically diverse order of trilobite found in strata dated from the Middle Cambrian to the Silurian. The order contains six superfamilies, but no suborders. Asaphids comprise some 20% of described fossil trilobites. This is one of the 35+ species of the Asaphus trilobites and is believed to be the progenitor of two major lines of Asaphus trilobites.
The Asaphida generally have cephalon (head) and pygidium (tail) parts similar in size, and most species have a prominent median ventral suture. Heads are often flat, and carapace furrows in the head area are often faint or not visible. Thoracic segments typically number 5 - 12, though some species have as few as two and some as many as 30. They also generally have a wide doublure, or rim, that surrounds the cephalon. This causes some specimens to be described as having a characteristic "snowplow" shaped cephalon. Eyes are typically large.
The major extinction event marking the end of the Ordovician Period reduced the diversity of all trilobite orders with most Asaphid families disappearing. The only surviving Asaphids were members of Superfamily Trinucleioidea, and they too disappeared before the end of the Silurian Period.
The region in which these trilobites lived was subject to dramatic changes in salinity and turbidity, and the trilobites were able to make rapid (geologically speaking) evolutionary adjustments. These adjustments were thought to be able to allow them to see both predator and prey more easily.
The fossils of this species are found only in the middle Ordovician deposits of the Lava River region near Saint Petersburg, Russia.
This excellently-preserved specimen measures 3.9 cm x 5.9 cm x 1.1 cm. The matrix measures approximately 6.2 cm wide by 7.0 cm long by 2.0 cm thick.
Restoration on this specimen is <3%.
Lava River, Kunda Level
St. Petersburg region
ITEM# TRILO-Russia-0020
This is a well-inflated and museum-quality example of the rare and impressive asaphid trilobite Asaphus raniceps from the Lower Ordovician deposits near St. Petersburg, Russia. Asaphus raniceps is a member of the Order Asaphida, Family Asaphidae. Asaphus raniceps is one of the 35 species of trilobite of the genus Asaphus. This taxon was a stem trilobite that ultimately led to Asapahus ornatus, the last survivor of the genus.
Sometime during the Ordovician period, an inland sea formed in what is now Eastern Europe. The sea contained a remarkably diverse trilobite fauna. Over a dozen species of Asaphus developed in this sea, with many species, including unrelated species, developing long eyestalks (officially called "peduncles") in various lengths. That so many species of trilobite developed eyestalks suggests that they were trying to overcome increased turbidity, or there was some sort of massive selective pressure leading these trilobites to bury themselves in the substrate up to their eyes. This species may have lain in wait buried in a benthic layer of loose debris or sediment with only its periscope eyestalks protruding above, looking out for danger or prey. Asaphida is a large, morphologically diverse order of trilobite found in strata dated from the Middle Cambrian to the Silurian. The order contains six superfamilies, but no suborders. Asaphids comprise some 20% of described fossil trilobites. This is one of the 35+ species of the Asaphus trilobites and is believed to be the progenitor of two major lines of Asaphus trilobites.
The Asaphida generally have cephalon (head) and pygidium (tail) parts similar in size, and most species have a prominent median ventral suture. Heads are often flat, and carapace furrows in the head area are often faint or not visible. Thoracic segments typically number 5 - 12, though some species have as few as two and some as many as 30. They also generally have a wide doublure, or rim, that surrounds the cephalon. This causes some specimens to be described as having a characteristic "snowplow" shaped cephalon. Eyes are typically large.
The major extinction event marking the end of the Ordovician Period reduced the diversity of all trilobite orders with most Asaphid families disappearing. The only surviving Asaphids were members of Superfamily Trinucleioidea, and they too disappeared before the end of the Silurian Period.
The region in which these trilobites lived was subject to dramatic changes in salinity and turbidity, and the trilobites were able to make rapid (geologically speaking) evolutionary adjustments. These adjustments were thought to be able to allow them to see both predator and prey more easily.
The fossils of this species are found only in the middle Ordovician deposits of the Lava River region near Saint Petersburg, Russia.
This excellently-preserved specimen measures 3.9 cm x 5.9 cm x 1.1 cm. The matrix measures approximately 6.2 cm wide by 7.0 cm long by 2.0 cm thick.
Restoration on this specimen is <3%.