Ooedigera

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Ooedigera
Temporal range: Cambrian Stage 3, 519–516.5  Ma
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Ooedigera peeli type.jpg
Type specimen
Ooedigera-peeli-JD-2020-1.png
Artist's restoration
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum:† Vetulicolia
Class:† Vetulicolida
Order:† Vetulicolata
Family:† Vetulicolidae
Genus:† Ooedigera
Species:
†O. peeli
Binomial name
†Ooedigera peeli
Vinther et al. 2011

Ooedigera peeli is an extinct vetulicolian from the Early Cambrian of North Greenland. The front body was flattened horizontally, oval-shaped, likely bearing a reticulated or anastomosing pattern, and had 5 evenly-spaced gill pouches along the midline. The tail was also bulbous and flattened horizontally, but was divided into 7 plates connected by flexible membranes, allowing movement. Ooedigera likely swam by moving side-to-side like a fish. It may have lived in an oxygen minimum zone alongside several predators in an ecosystem based on chemosynthetic microbial mats, and was possibly a deposit or filter feeder living near the seafloor.

Contents

Etymology

The genus name Ooedigera derives from Ancient Greek ooedis "egg-shaped/oval" and geros "old". The species name peeli is in honour of Professor John S. Peel from the Geological Survey of Greenland, who especially researched the locality Ooedigera was discovered in. [1]

Taxonomy

Sirius Passet in the Early Cambrian Sirius Passet in the Cambrian.png
Sirius Passet in the Early Cambrian

The type specimen MGUH 29279 was discovered in the Early Cambrian Sirius Passet Lagerstätte of the North Greenlandic Buen Formation. The area corresponds to the early Cambrian Stage 3 about 519–516.5 million years ago. The specimen is a flat compression fossil preserved in fissile mudstone, with an odd, thin lamination, and several small splotches which represent the remains of various other creatures, such as sponges and trilobites. [1]

Ooedigera is classified in the extinct Cambrian subphylum Vetulicolia in the family Vetulicolidae along with Vetulicola . Ooedigera is the third vetulicolid found outside the Chinese Maotianshan Shales (the others are an undescribed specimen from Mural Formation, Canada [1] and Nesonektris from Emu Bay Shale, Australia [2] ).

Vetulicolia is a subphylum of primitive Deuterostomia, a large group of animals whose first opening in fetal development becomes the anus as opposed to the mouth as in protostomes. [3] The subphylum was originally classified in Arthropoda, but had been reassigned several times. It was suggested to represent primitive chordates [4] or an invalid grouping of primitive tunicates. [5] The subphylum was also suggested to be more closely related to protostomes, [6] as an ecdysozoan (which includes arthropods, nematodes, and related taxa), specifically kinorhynchans (segmented worm-like creatures). [7]

Anatomy

The type specimen is 41.3 mm (1.63 in) long in total, and the body plan is divided into an ovoid front body and a segmented tail. The type specimen seems to have been compressed on its side during fossilization, and due to the irregular folding of the outline, the skin may have been softer than in other vetulicolians. [1]

The front body was oval-shaped, measuring 22.5 mm (0.9 in) in length and 14 mm (0.55 in) in height, and flattened horizontally. It had a straight front edge, and the back edge came to a point, intersecting at the midline of the front body. Unlike Chinese vetulicolians, the type specimen shows no indication of a ridge running along the midline, and a lack of such in Ooedigera would be significant in terms of its taxonomy, but more specimens are required to confirm this. Like other vetulicolians, the midline had 5 more or less evenly spaced openings, 3.3 mm (0.13 in) from the front edge and 2.4 mm (0.094 in) from the back edge, corresponding to gill pouches. The front body seems to have had a reticulated or anastomosing pattern. [1] This could possibly indicate the specimen was a juvenile, as such ornamentation is seen in what are thought to be juvenile specimens of the vetulicolian Beidazoon . [8]

Like other vetulicolians, the tail was asymmetrical, flattened horizontally, and divided into 7 segments which were connected by flexible membranes, the latter allowing movement. It is 18.8 mm (0.74 in) long and 8.7 mm (0.34 in) high. Each segment had concave edges, which gave each one an hourglass shape in side-view. Segments 2–7 were flat on the underside, and segments 5–7 were also flat on the top. The last segment was shorter than in other vetulicolians. Given the asymmetrical flattening, the tail likely propelled by flexing side-to-side like a fish rather than up-and-down. [1]

Palaeocology

It is largely unknown what vetulicolians fed upon. Lacking mouths adapted for chewing or grasping, they were probably not predators or scavengers. Lacking limbs, it is unlikely they were burrowers or lived on the seafloor, rather inhabiting the water column (nektonic) but perhaps staying near the seafloor (nektobenthic). They may have been passive floaters, but it is possible that the gills were used for jet propulsion like thaliaceans. [9] The gills may have also been used in filter feeding, actively swallowing and expelling water using the mouth and gills respectively. [10] [9] However, Vetulicola , Banffia , and Pomatrum have remains of sediments in the gut, which is either evidence of deposit feeding on the seafloor [6] [9] or a result of fossilization. It is possible vetulicolians used both feeding methods like the modern acorn worm Balanoglossus . [9]

About 45 species have been discovered in Sirius Passet, mostly endemic fauna, including trilobites, sponges, worms, and the extinct halkieriids and lobopodians. [11] Another indeterminate vetulicolian was found here. [1] The area may have been an oxygen minimum zone, and, like the preceding Ediacaran, the ecosystem may have been primarily based on chemosynthetic microbial mats which fed grazers and filter feeders. Arthropods and sponges are the most common fossils, and members of the former and lobopodians may have been major predators. Predators appear to have been the most common animals. [11]

Related Research Articles

<span class="mw-page-title-main">Vetulicolia</span> Extinct Cambrian taxon of deuterostomes

Vetulicolia is a phylum of bilaterian animals encompassing several extinct species belonging to the Cambrian period. The phylum was created by Degan Shu and his research team in 2001, and named after Vetulicola cuneata, the first species of the phylum described in 1987.

<span class="mw-page-title-main">Maotianshan Shales</span> Series of Early Cambrian deposits in the Chiungchussu Formation

The Maotianshan Shales (帽天山页岩) are a series of Early Cambrian sedimentary deposits in the Chiungchussu Formation, famous for their Konservat Lagerstätten, deposits known for the exceptional preservation of fossilized organisms or traces. The Maotianshan Shales form one of some forty Cambrian fossil locations worldwide exhibiting exquisite preservation of rarely preserved, non-mineralized soft tissue, comparable to the fossils of the Burgess Shale of British Columbia, Canada. They take their name from Maotianshan Hill in Chengjiang County, Yunnan Province, China.

<i>Sidneyia</i> Extinct genus of arthropods

Sidneyia is an extinct arthropod known from fossils found from the Early to the Mid Cambrian of China and the Mid Cambrian Burgess Shale of British Columbia, Canada.

<span class="mw-page-title-main">Sirius Passet</span> Cambrian Lagerstätte in Greenland

Sirius Passet is a Cambrian Lagerstätte in Peary Land, Greenland. The Sirius Passet Lagerstätte was named after the Sirius sledge patrol that operates in North Greenland. It comprises six places in Nansen Land, on the east shore of J.P. Koch Fjord in the far north of Greenland. It was discovered in 1984 by A. Higgins of the Geological Survey of Greenland. A preliminary account was published by Simon Conway Morris and others in 1987 and expeditions led by J. S. Peel and Conway Morris have returned to the site several times between 1989 and the present. A field collection of perhaps 10,000 fossil specimens has been amassed. It is a part of the Buen Formation.

<span class="mw-page-title-main">Emu Bay Shale</span> Geological formation in South Australia

The Emu Bay Shale is a geological formation in Emu Bay, South Australia, containing a major Konservat-Lagerstätte. It is one of two in the world containing Redlichiidan trilobites. The Emu Bay Shale is dated as Cambrian Series 2, Stage 4, correlated with the upper Botomian Stage of the Lower Cambrian.

<i>Vetulicola</i> Fossil genus of marine animal

Vetulicola is an extinct genus of marine animal discovered from the Cambrian of China. It is the eponymous member of the enigmatic phylum Vetulicolia, which is of uncertain affinities but may belong to the deuterostomes. The name was derived from Vetulicola cuneata, the first species described by Hou Xian-guang in 1987 from the Lower Cambrian Chiungchussu Formation in Chengjiang, China.

<i>Pomatrum</i> Cambrian age animal

Pomatrum is an extinct vetulicolian, the senior synonym of Xidazoon; the latter taxon was described by Shu, et al. (1999) based on fossils found in the Qiongzhusi (Chiungchussu) Formation, Yu'anshan Member, Lower Cambrian, Haikou, (Kunming), about 50 km west of Chengjiang, China. It has been likened to the chordate Pipiscius.

<i>Banffia</i> Extinct genus of Cambrian organisms

Banffia is a genus of animals described from Middle Cambrian fossils. The genus commemorates Banff, Alberta, near where the first fossil specimens were discovered. Its placement in higher taxa is controversial. It is considered to be a member of the enigmatic phylum Vetulicolia.

<span class="mw-page-title-main">Vetulicolidae</span> Extinct family of soft-bodied animals

Vetulicolidae is an extinct family of Early Cambrian deuterostomes comprising two genera: Vetulicola and Ooedigera.

<i>Buenellus</i> Species of trilobite (fossil)

Buenellus higginsi is an average size trilobite, which lived during the Lower Cambrian period, in what is now North-West Greenland. It is a prominent member of the Sirius Passet fauna. Buenellus higginsi is the only known species in the genus Buenellus.

A number of assemblages bear fossil assemblages similar in character to that of the Burgess Shale. While many are also preserved in a similar fashion to the Burgess Shale, the term "Burgess Shale-type fauna" covers assemblages based on taxonomic criteria only.

<span class="mw-page-title-main">Deuterostome</span> Superphylum of bilateral animals

Deuterostomes are bilaterian animals of the superphylum Deuterostomia, typically characterized by their anus forming before the mouth during embryonic development. Deuterostomia is further divided into 4 phyla: Chordata, Echinodermata, Hemichordata, and the extinct Vetulicolia known from Cambrian fossils. The extinct clade Cambroernida is also thought to be a member of Deuterostomia.

<i>Isoxys</i> Genus of extinct arthropods

Isoxys is a genus of extinct bivalved Cambrian arthropod; the various species of which are thought to have been freely swimming predators. It had a pair of large spherical eyes, and two large frontal appendages used to grasp prey.

<i>Vetulicola cuneata</i> Extinct species of animal

Vetulicola cuneata is a species of extinct animal from the Early Cambrian Chengjiang biota of China. It was described by Hou Xian-guang in 1987 from the Lower Cambrian Chiungchussu Formation, and became the first animal under an eponymous phylum Vetulicolia.

<i>Kiisortoqia</i> Extinct genus of arthropods

Kiisortoqia soperi is an extinct species of arthropod from the Early Cambrian Sirius Passet Lagerstätte in Greenland. While it had a superficially trilobite-like bodyform, it also possessed large frontal appendages similar to those of radiodonts.

<i>Skeemella</i>

Skeemella clavula is an elongate animal from what is now the Middle Cambrian Wheeler Shale and Marjum lagerstätte of Utah. It has been classified with the vetulicolians.

<i>Buenaspis</i> Small Cambrian arthropod

Buenaspis is a genus of small nektaspid arthropod, that lived during the early Cambrian period. Fossil remains of Buenaspis were collected from the Lower Cambrian Sirius Passet Lagerstätte of North Greenland. Buenaspis looks like a soft eyeless trilobite. It has a headshield slightly larger than the tailshield (pygidium), and in between them six thoracic body segments (somites). The genus is monotypic, its sole species being Buenaspis forteyi.

<span class="mw-page-title-main">Nesonektris</span> Extinct genus of Cambrian Era Chordate

Nesonektris aldridgei is an extinct deuterostome chordate from the Late Botomian-aged Emu Bay Shale Lagerstätte in Kangaroo Island, Australia. So far, it is the fourth described vetulicolian that is not restricted to the Maotianshan Shales.

<i>Squamacula</i> Extinct genus of arthropods

Squamacula is an extinct artiopodan arthropod from the Cambrian Series 2. The type species S. clypeata was described in 1997 from the Chengjiang biota of Yunnan, China. At the time of description there were only two known specimens of S. clypeata, but now there are at least six known specimens. In 2012 a second species S. buckorum was described from the Emu Bay Shale of Australia.

<i>Thulaspis</i>

Thulaspis is an extinct genus of artiopodan arthropod from the Cambrian Stage 3 aged Sirius Passet site in Greenland. It is thought to be a close relative of Squamacula, and is possibly one of the most basal members of Artiopoda.

References

  1. 1 2 3 4 5 6 7 Vinther, J.; Smith, M. P.; Harper, D. A. T. (2011). "Vetulicolians from the Lower Cambrian Sirius Passet Lagerstätte, North Greenland, and the polarity of morphological characters in basal deuterostomes". Palaeontology. 54 (3): 711–719. doi:10.1111/j.1475-4983.2011.01034.x. S2CID   85602402.
  2. ↑ García-Bellido, D. C.; Lee, M. S. Y.; Edgecombe, G. D.; Jago, J. B.; Gehling, J. G.; Paterson, G. R. (2014). "A new vetulicolian from Australia and its bearing on the chordate affinities of an enigmatic Cambrian group". BMC Evolutionary Biology. 14 (214): 214. doi: 10.1186/s12862-014-0214-z . PMC   4203957 . PMID   25273382.
  3. ↑ Shu, D. G.; Conway Morris, S.; Zhang, Z. F.; Han, J. (2010). "The earliest history of the deuterostomes: the importance of the Chengjiang Fossil‐Lagerstätte". Proceedings of the Royal Society B. 277 (1679): 165–174. doi:10.1098/rspb.2009.0646. PMC   2842668 . PMID   19439437.
  4. ↑ Gee, H. (2001). "On being vetulicolian". Nature. 414 (6862): 407–409. doi:10.1038/35106680. PMID   11719790. S2CID   4381895.
  5. ↑ Lacalli, L. C. (2002). "Vetulicolians--are they deuterostomes? chordates?". BioEssays. 24 (3): 208–211. doi:10.1002/bies.10064. PMID   11891757.
  6. 1 2 Caron, J.-B. (2006). "Banffia constricta, a putative vetulicolid from the Middle Cambrian Burgess Shale". Transactions of the Royal Society of Edinburgh: Earth Sciences. 96 (2): 95–111. doi:10.1017/S0263593300001255. S2CID   128851764.
  7. ↑ Briggs, D. E. G.; Lieberman, B. S.; Halgedahl, S. L.; Jarrard, R. D. (2005). "A new metazoan from the Middle Cambrian of Utah and the nature of the Vetulicolia". Palaeontology. 48 (4): 681–686. doi: 10.1111/j.1475-4983.2005.00489.x .
  8. ↑ McMenamin, M. C. (2019). "Cambrian Chordates and Vetulicolians". Geosciences. 9 (8): 354. Bibcode:2019Geosc...9..354M. doi: 10.3390/geosciences9080354 .
  9. 1 2 3 4 Aldridge, R. J.; Xian-Guang, H.; Siveter, D. J.; Gabbot, S. E. (2007). "The systematics and phylogenetic relationships of vetulicolians". Palaeontology. 50 (1): 162–163. doi:10.1111/j.1475-4983.2006.00606.x. S2CID   85722738.
  10. ↑ Ou, Q.; Conway Morris, S.; Han, J.; Zhang, Z.; Liu, J.; Chen, A.; Zhang, X.; Shu, D. (2012). "Evidence for gill slits and a pharynx in Cambrian vetulicolians: implications for the early evolution of deuterostomes". BMC Biology. 10 (81): 81. doi: 10.1186/1741-7007-10-81 . PMC   3517509 . PMID   23031545.
  11. 1 2 Harper, D. A. T.; Hammarlund, E. U.; Topper, T. P.; Nielsen, A. T.; Rasmussen, J. A.; Park, T.-Y. S.; Smith, M. P. (2019). "The Sirius Passet Lagerstätte of North Greenland: a remote window on the Cambrian Explosion" (PDF). Journal of the Geological Society. 176 (6): 1023–1037. Bibcode:2019JGSoc.176.1023H. doi:10.1144/jgs2019-043. S2CID   198424068.
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