Biology:Ichnusa cocozzi
| Ichnusa cocozzi Temporal range: Ediacaran Period, 635-541 Ma
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| Scientific classification | |
| Kingdom: | Animalia
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| Phylum: | |
| Class: | |
| Order: | Incertae sedis
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| Family: | Incertae sedis
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| Genus: | Ichnusa
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| Species: | I. cocozzi
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| Binomial name | |
| Ichnusa cocozzi | |
Ichnusa is a genus of cnidarians that inhabited during the Ediacaran period (635-541 Mya) discovered in the region of Sardinia, Italy.[1] The genus is represented by one species, Ichnusa cocozzi, which was a marine cnidarian belonging to the Scyphozoa class[2]
Morphology, anatomy & behavior
Ichnusa cocozzi is described as a hemispherical or pyramidal scyphozoan that inhabited the Ediacaran period.[3] Three individuals of I. cocozzi have been described: one holotype and two paratypes.[2] None of the individuals preserve their internal organs, and the holotype is the only one to preserve tentacles. The holotype has a diameter of 27.6 mm x 20 mm.[1] The tentacles preserved in the holotype are 1.2 mm long, and between 0.25 and 0.5 mm wide.[1] This scyphozoan had four radial lobes that come out of a center that doesn’t have any structure preserved. These lobes subdivide into 2, and then into 4 more smaller lobes. It is difficult to know if the organism had a gastrovascular system of four or eight first-order lobes. Ichnusa cocozzi was a marine organism[4]
Method of fossilization
Ichnusa. cocozzi fossils have been discovered on the San Vito Formation, in Italy. There are several other medusoid fossils found on this place.[3] The fossils found are molds that are circular or oval in shape. The molds form a fine silt pellicle that are darker than the rest of the rock. As mentioned before, medusoids (including I. cocozzi) found in the San Vito Formation are believed to be pyramidal or hemispherical, but because of the weight of the superincumbent strata, they have all been flattened[3]
Distribution & paleoenvironment
Specimens have been found in the San Vito Formation in the Sarrabus area of Sardinia, to the northeast of Cagliari, Italy.[1] Due to polyphase deformation, the San Vito Formation is of uncertain stratigraphic age. However, the fossils found in the formation suggest a late Precambrian (Ediacaran) age. Fossils were found within a 700 meters thick series of grits, quartzites, and shales that are green and yellow in color.[3]
Other notable characteristics
When described, the complexity of the gastrovascular system of I. cocozzi resembled the one found in Albumares, described by Fedonkin (1976) from the Valdai horizon on the Onega Peninsula. I. cocozzi also resembles Rugoconites, first described by Wade (1972) and Wade (1984)[1].It’s considered that the symmetry of Ichnusa is four- or eight-fold, which suggest that this genus belonged to the Scyphozoa class.[1]
References
- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 Debrenne, F.; Naud, G. (1981-01-01). "Meduses et traces fossiles supposees precambriennes dans la formation de San Vito, Sarrabus, Sud-Est de la Sardaigne". Bulletin de la Société Géologique de France S7-XXIII (1): 23–31. doi:10.2113/gssgfbull.S7-XXIII.1.23. ISSN 0037-9409. https://doi.org/10.2113/gssgfbull.S7-XXIII.1.23.
- ↑ 2.0 2.1 "Spécimen fossile - HOLOTYPE Ichnusa cocozzi DEBRENNE & NAUD, 1981". https://science.mnhn.fr/institution/mnhn/collection/f/item/a48869?listIndex=1&listCount=3.
- ↑ 3.0 3.1 3.2 3.3 McCall, G.J.H. (July 2006). "The Vendian (Ediacaran) in the geological record: Enigmas in geology's prelude to the Cambrian explosion" (in en). Earth-Science Reviews 77 (1–3): 1–229. doi:10.1016/j.earscirev.2005.08.004. Bibcode: 2006ESRv...77....1M. https://linkinghub.elsevier.com/retrieve/pii/S0012825205001662.
- ↑ "Ichnusa cocozzi Debrenne & Naud 1981 - Encyclopedia of Life". https://eol.org/pages/47069519.
Wikidata ☰ Q110110634 entry
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