Olenoides
| Olenoides Temporal range:
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| File:Olenoides superbus, Late Middle Cambrian, Upper Marjum Formation, House Range, Millard County, Utah, USA - Houston Museum of Natural Science - DSC01415.JPG | |
| Olenoides superbus from the Upper Marjum Formation | |
| File:Olenoides serratus 3d.jpg | |
| 3D reconstruction of Olenoides serratus | |
Scientific classification 
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| Kingdom: | Animalia |
| Phylum: | Arthropoda |
| Clade: | †Artiopoda |
| Class: | †Trilobita |
| Order: | †Corynexochida |
| Family: | †Dorypygidae |
| Genus: | †Olenoides Meek, 1877 |
Olenoides was a trilobite from the Cambrian period. Its fossils are found well-preserved in the Burgess Shale in Canada. It grew up to 9 centimetres (3.5 in) long.
Etymology
[edit | edit source]Olenoides – from Olenus, in Greek mythology a man who, along with his wife Lethaea, was turned to stone. Olenus was used for a trilobite genus name in 1827; the suffix -oides(“resembling”) was added later.
Discussion
[edit | edit source]Olenoides followed the basic structure of all trilobites — a cephalon (head shield), a thorax with seven jointed parts, and finally a semicircular pygidium. Its antennae were long, and curved back along its sides. Its thin legs show that it was no swimmer, instead crawling along the sea floor in search of prey. This is also evidenced by fossil tracks that have been found. Conspicuous W-shaped wounds, often partially healed, on Olenoides specimens may be due to predation by Anomalocaris.[1]
Its major characteristics are a large parallel-sided glabella, deep interpleural furrows on the pygidium, and slender pygidial spines, as well as the fact that it is the most common limb-bearing trilobite species in the Burgess Shale.
Specimens have been found in the Marjumian of the United States (Utah and New York). General Cambrian fossils have been found in Canada (British Columbia and Newfoundland), Greenland, Kazakhstan, Russia, and the USA (Idaho, Nevada for which O. nevadensis is named, New York, Pennsylvania for which O. pennsylvanicus is named, Virginia, Utah, and Wyoming).[2]
213 specimens of Olenoides are known from the Greater Phyllopod bed, where they comprise 0.4% of the community.[3] The Burgess Shale's preservative qualities have helped Olenoides become one of the best known of trilobites.
Synonyms
[edit | edit source]
Olenoides was formerly known as Neolenus. Species of Kootenia are no longer considered different enough from those in Olenoides to warrant placement in a separate genus.[4]
Species
[edit | edit source]- O. nevadensis
- O. sassikaspa
- O. serratus
- O. superbus
- O. dawsoni (formerly placed in Kootenia)
- O. burgessensis (formerly placed in Kootenia)
- O. buttsi (unrecognized)
- O. convexus (unrecognized)
- O. incertus (unrecognized)
- O. pennsylvanicus (unrecognized)
Description
[edit | edit source]Olenoides is an average size trilobite (up to 9 cm long), broadly oval in outline. Its cephalon is semi-circular. The glabella is parallel-sided, rounded at its front and almost reaches the anterior border. Narrow occular ridges curve backwards from the front of the glabella to the small, outwardly-bowed eyes. The librigenae narrow backward into straight, slender genal spines that reach as far as the third thorax segment. Thorax consists of seven segments that end in needle-like spines. pygidium) has six axial rings that decrease in size backwards and four or five pairs of rearward pointing marginal spines. Cephalon, thorax and pygidium are of approximately equal length.[5]
Olenoides serratus is one of about twenty species of which the non-calcified parts are known, due to so-called soft tissue preservation. The antennae are the most anterior pair of appendages in trilobites. In O. serratus, these are attached about halfway the immediately adjacent to the hypostome, and appear from the dorsal side under the cephalon in front of the side of the glabella. They were flexible, having a tubular shape that became narrower towards anterior and composed of between 40 and 50 segments that are each shorter than wide. Olenellus serratus is the only known trilobite with cerci, uniramous appendages on ventral side of last pygidial segment, and these are shaped like the antennas.[6]
See also
[edit | edit source]References
[edit | edit source]- ^ Coppold, Murray and Wayne Powell (2006). A Geoscience Guide to the Burgess Shale, p.60. The Burgess Shale Geoscience Foundation, Field, British Columbia. Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value)..
- ^ Paleobiology Database. "Chancia", accessed March 27, 2011
- ^ Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
- ^ Coppold, Murray and Wayne Powell (2006). A Geoscience Guide to the Burgess Shale, p.59. The Burgess Shale Geoscience Foundation, Field, British Columbia. Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value)..
- ^ Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
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- Olenoides on the Smithsonian institution website
- A fossil photograph of Olenoides nevadensis
- Paleozoic Olenoides Yu-Gi-Oh!
External links
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