Vetulicolia

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Vetulicolia
Temporal range: about 520–501  Ma
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Cambrian Stage 3—Drumian - Possible Ediacaran record [1]
Vetulicola cuneata uetsurikora kunieta 1.jpg
Fossil of Vetulicola cuneata
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Clade?:† Vetulicolia
Shu et al. 2001
Type species
† Vetulicola cuneata
Hou, 1987
Classes
  • †Banffozoa
  • †Vetulicolida

Vetulicolia [note 1] is a clade of bilaterian animals encompassing several extinct species belonging to the Cambrian period. [2] [3] The clade was created by Degan Shu and his research team in 2001, [4] and named after Vetulicola cuneata , the first species of the phylum described in 1987. [5]

Contents

The vetulicolian body plan comprises two parts: a voluminous rostral (anterior) forebody, tipped with an anteriorly positioned mouth and lined with a lateral row of five round to oval-shaped openings on each side, which have been interpreted as gills (or at least orifices in the vicinity of the pharynx); and a caudal (posterior) section that primitively comprises seven body segments and functions as a tail. All vetulicolians lack preserved appendages of any kind, having no legs, feelers or even eye spots. [6] The area where the anterior and posterior parts join is constricted. [7]

Their taxonomic affinity has been uncertain; they have been interpreted as stem- and crown-group arthropods, stem-group vertebrates, [8] and early deuterostomes (a group which as a whole includes the vertebrates, other invertebrate chordates, echinoderms and hemichordates). The general scientific consensus before 2001 considered them early limbless arthropods but now considers them early deuterostomes. [9] Vetulicolian fossils examined in 2014 show the presence of notochord-like structures, and it was concluded that vetulicolians are crown-group chordates and probably related to modern tunicates. [10] Research from 2017 rather indicates vetulicolians are related to Saccorhytus , another basal deuterostome group, [11] although another study shows possibility that Saccorhytus is ecdysozoan instead of deuterostome. [12] A 2024 paper, however, found vetulicolians to be a paraphyletic group at the base of Chordata. [13] Banffozoa’s inclusion within this group is dubious, due to their lack of gill slits and apparent gut diverticula, and so they may be within Protostomia instead. [14]

Taxonomy and evolution

Vetulicolia as a phylum was created by Chinese palaeontologist Degan Shu and his research team at the Northwest University in Xi'an, China, along with Simon Conway Morris at the University of Cambridge in 2001. [4] 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. [3] [5] The purpose was to include all related Cambrian animals known under the families Didazoonidae ( Didazoon , Pomatrum , and Xidazoon ) and Vetulicolidae ( Vetulicola , and Banffia ) as a separate group of animals. [2] [4] Other animals which may be related include the yunnanozoans. [4]

The taxonomic placement of the vetulicolians remains controversial. The original researcher Shu is of the opinion that the vetulicolians probably represent an early type of deuterostomes, and that this implies that segmentation in cephalochordates and vertebrates may be derived from the common ancestor of protostomes and deuterostomes. [8] However, Derek Briggs of Yale University and his team who described Skeemella from the Middle Cambrian of Utah regard it as having affinity to protostomes with important arthropod features, thus confounding assignment of Vetulicolia to Deuterostomia. [15] Thurston C. Lacalli of the University of Saskatchewan, Saskatoon, Canada, agreed that the group are deuterostomes, but suggested that the animals were more likely related to tunicates. [16]

Dominguez and Jefferies have argued, based on morphological analysis, that Vetulicola (and by implication, other vetulicolians) is a urochordate, and probably a stem-group larvacean. Some question the relation to tunicates and larvaceans, as there is no evidence of segmentation in tunicates, larval or adult, that is comparable to segmentation in vetulicolians, that the anus of urochordates is within the atrium, while that of vetulicolians is positioned at the terminal end of the tail, and, perhaps most importantly, there is no exhalant siphon, or analogous structure, seen in vetulicolians. [17] However, a discovery of a new vetulicolian, Nesonektris aldridgei, from Australia in 2014 supported a position close to urochordates for vetulicolians. [10]

A 2024 phylogenetic analysis by Mussini and colleagues found vetulicolians to be a paraphyletic group of stem-chordates, lying outside a clade formed by Yunnanozoon , Cathaymyrus , Pikaia and crown-chordates. [13]

Chordata
Vetulicolia

Ecology and lifestyle

Fossil of Skeemella clavula Skeemella clavula KUMIP 310501.jpg
Fossil of Skeemella clavula

From their superficially tadpole-like forms, leaf or paddle-shaped tails, and various degrees of streamlining, it is assumed that all vetulicolians discovered to date were swimming animals that spent much, if not all, of their time living in water. [17] Some groups, like the genus Vetulicola, were more streamlined (complete with ventral keels) than other groups, such as the tadpole-like Didazoonidae. [17]

Because all vetulicolians had mouths which had no features for chewing or grasping, it is assumed that they were not predators. [17] Since vetulicolians possessed gill slits, many researchers regard these organisms as planktivores. The sediment infills in the guts of their fossils have caused some to suggest that they were deposit feeders. This idea has been contested, as deposit feeders tend to have straight guts, whereas the hindguts of vetulicolians were spiral-shaped. Some researchers propose that the vetulicolians were "selective deposit-feeders" which actively swam from one region of the seafloor to another, while supplementing their nutrition with filter-feeding. [17]

Classification

Notes

  1. ↑ The taxon name, Vetulicolia, is derived from the type genus, Vetulicola , which is a compound Latin word composed of vetuli "old" and cola "inhabitant".

Related Research Articles

<span class="mw-page-title-main">Chordate</span> Phylum of animals having a dorsal nerve cord

A chordate is a deuterostomic bilaterial animal belonging to the phylum Chordata. All chordates possess, at some point during their larval or adult stages, five distinctive physical characteristics (synapomorphies) that distinguish them from other taxa. These five synapomorphies are a notochord, a hollow dorsal nerve cord, an endostyle or thyroid, pharyngeal slits, and a post-anal tail.

<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>Yunnanozoon</i> Cambrian fossil chordate

Yunnanozoon lividum is an extinct species of bilaterian animal from the Lower Cambrian Chengjiang biota of Yunnan province, China. Its affinities have been long the subject of controversy.

<i>Haikouichthys</i> Extinct genus of jawless fishes

Haikouichthys is an extinct genus of craniate that lived 518 million years ago, during the Cambrian explosion of multicellular life. The type species, Haikouichthys ercaicunensis, was first described in 1999. Haikouichthys had a defined skull and other characteristics that have led paleontologists to label it a true craniate, and even to be popularly characterized as one of the earliest fishes. More than 500 specimens were referred to this taxon and phylogenetic analyses indicates that the animal is probably a basal stem-craniate. Some researchers have considered Haikouichthys to be synonymous with the other primitive chordate Myllokunmingia, but subsequent studies led by the British paleontologist Simon Conway Morris identified both genera to be distinct, separate taxa on the basis of different gill arrangement, the absence of branchial rays in Myllokunmingia and the myomeres having a more acute shape in Haikouichthys.

<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.

<i>Cathaymyrus</i> Extinct genus of chordates

Cathaymyrus is a genus of Early Cambrian chordate known from the Chengjiang biota in Yunnan Province, China. Both species have a long segmented body with no distinctive head. The segments resemble the v-shaped muscle blocks found in cephalochordates such as Amphioxus. A long linear impression runs along the "back" of the body looking something like a chordate notochord.

<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 four phyla: Chordata, Echinodermata, Hemichordata, and the extinct Vetulicolia known from Cambrian fossils. The extinct clade Cambroernida is thought to be a member of Deuterostomia.

<i>Chuandianella</i> Extinct genus of Cambrian animals

Chuandianella ovata is an extinct bivalved arthropod that lived during Cambrian Stage 3 of the Early Cambrian. It is the only species classified under the genus Chuandianella. Its fossils were recovered from the Chengjiang Biota in Yunnan, China.

<i>Miraluolishania</i> Extinct genus of lobopodians

Miraluolishania is an extinct lobopodian known from Chengjiang County in China. It is remarkable for the possession of lensed pit-eyes. The only species, Miraluolishania haikouensis, was described from the Maotianshan Shales at Haikou by Jianni Liu and Degan Shu in 2004. In 2009, a team of palaeontologists at the Yunnan University, led by Xiaoya Ma reported the discovery of 42 other specimens from Haikou. With the help of Swiss palaeontologist Jan Bergström, Ma and Hou came to the conclusion that all the specimens were the same species as Luolishania; another lobopod discovered from the Chengjian in 1989. Chengjian is 40 kms from Haikou and the fossil fauna are different. A reassessment by Liu and Shu's team at the Northwest University in 2008 established that Luolishania and Miraluolishania are distinct animals.

<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>Phlogites</i> Genus of ambulacrarians

Phlogites, a senior synonym of Cheungkongella ancestralis, is a cambroernid, and thus a member of the deuterostome total group. It is known from the Lower Cambrian Haikou Chengjiang deposits of China, and was initially compared to the tunicates. It was originally described as a tunicate, though, this identification has been questioned, especially with the discovery of another Chengjiang tunicate, Shankouclava. It has most recently been interpreted as a cambroernid related to Eldonia, Rotadiscus and Herpetogaster.

<i>Ooedigera</i> Ovoid Cambrian animal with a bulbous tail

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.

<i>Skeemella</i> Extinct genus of bilaterians

Skeemella is a genus of elongate animals from what is now the Middle Cambrian Wheeler Shale and Marjum lagerstätte of Utah. It has been classified with the vetulicolians.

<i>Vetulicola rectangulata</i> Extinct animal from Cambrian of the Chengjiang biota of China

Vetulicola rectangulata is a species of extinct animal from the Early Cambrian of the Chengjiang biota of China. Regarded as a deuterostome, it has characteristic rectangular anterior body on which the posterior tail region is attached. It was described by Luo Huilin and Hu Shi-xue in 1999.

<i>Saccorhytus</i> Extinct monospecific genus of Ediacaran Ecdysozoan

Saccorhytus is an extinct genus of animal possibly belonging to the superphylum Ecdysozoa, and it is represented by a single species, Saccorhytus coronarius. The organism lived approximately 540 million years ago in the beginning of the Cambrian period. Initially proposed as a deuterostome, which would make it the oldest known species of this superphylum, it has since been determined to belong to a protostome group called the ecdysozoans.

Shankouclava is an extinct genus of tunicates. It represents the oldest candidate member of this group, dating to 518 million years ago. It has been found in the Lower Cambrian Maotianshan Shale at Shankou village, Anning, near Kunming. Each of the eight specimens found and used for description were isolated, suggesting that the genus was solitary and not colonial.

<i>Beidazoon</i> Extinct species of Cambrian organism

Beidazoon venustum is a deuterostome from the deuterostome group Vetulicolia. It originates from the lower Cambrian Chengjiang biota of Yunnan Province, China. Beidazoon was a marine organism discovered by Degan Shu in 2005.

The Cambrian chordates are an extinct group of animals belonging to the phylum Chordata that lived during the Cambrian, between 538 and 485 million years ago. The first Cambrian chordate known is Pikaia gracilens, a lancelet-like animal from the Burgess Shale in British Columbia, Canada. The discoverer, Charles Doolittle Walcott, described it as a kind of worm (annelid) in 1911, but it was later identified as a chordate. Subsequent discoveries of other Cambrian fossils from the Burgess Shale in 1991, and from the Chengjiang biota of China in 1991, which were later found to be of chordates, several Cambrian chordates are known, with some fossils considered as putative chordates.

References

  1. ↑ Liu, Junping; Chen, Ailin; Li, Binglin; Tang, Feng; Zhao, Jiangtai; Chen, Ke (2024-10-06). "Problematic Ediacaran sail-shaped fossils from eastern Yunnan, China". Historical Biology. Informa UK Limited: 1–7. doi:10.1080/08912963.2024.2403588. ISSN   0891-2963.
  2. 1 2 Shu, Degan (2005). "On the Phylum Vetulicolia". Chinese Science Bulletin. 50 (20): 2342–2354. Bibcode:2005ChSBu..50.2342S. doi:10.1007/BF03183746. ISSN   1001-6538. S2CID   86827605.
  3. 1 2 McMenamin, Mark A. S. (2019). "Cambrian Chordates and Vetulicolians". Geosciences. 9 (8): 354. Bibcode:2019Geosc...9..354M. doi: 10.3390/geosciences9080354 . ISSN   2076-3263.
  4. 1 2 3 4 Shu, D. G.; Conway Morris, S.; Han, J.; Chen, L.; Zhang, X. L.; Zhang, Z. F.; Liu, H. Q.; Li, Y.; Liu, J. N. (2001-11-22). "Primitive deuterostomes from the Chengjiang Lagerstätte (Lower Cambrian, China)". Nature. 414 (6862): 419–424. Bibcode:2001Natur.414..419S. doi:10.1038/35106514. ISSN   0028-0836. PMID   11719797. S2CID   4345484.
  5. 1 2 Briggs, Derek E. G.; Fortey, Richard A. (2005). "Wonderful strife: systematics, stem groups, and the phylogenetic signal of the Cambrian radiation". Paleobiology. 31 (2_Suppl): 94–112. doi:10.1666/0094-8373(2005)031[0094:WSSSGA]2.0.CO;2. ISSN   0094-8373. S2CID   44066226.
  6. ↑ Ailin, C.; Hongzhen, F.; Maoyan, Z.H.U.; Dongsheng, M.A.; Ming, L.I. (2003), "A New Vetulicolian from the Early Cambrian Chengjiang Fauna in Yunnan of China", Acta Geologica Sinica, 77 (3): 281–287, doi:10.1111/j.1755-6724.2003.tb00742.x, S2CID   128895860 [ dead link ]
  7. 1 2 McMenamin, Mark A. S. (11 August 2019). "Cambrian Chordates and Vetulicolians". Geosciences. 9 (8): 354. Bibcode:2019Geosc...9..354M. doi: 10.3390/geosciences9080354 .
  8. 1 2 Shu, Degan (2003). "A paleontological perspective of vertebrate origin". Chinese Science Bulletin. 48 (8): 725–735. Bibcode:2003ChSBu..48..725S. doi:10.1007/BF03187041. S2CID   85163902.
  9. ↑ Dominguez, Patricio and Jeffries, Richard. (2003). Fossil evidence on the origin of appendicularians. Paper read at International Urochordate Meeting 2003. Abstract at [2] – URL retrieved June 22, 2006.
  10. 1 2 3 García-Bellido, Diego C; Paterson, John R (2014). "A new vetulicolian from Australia and its bearing on the chordate affinities of an enigmatic Cambrian group". BMC Evolutionary Biology. 14: 214. doi: 10.1186/s12862-014-0214-z . PMC   4203957 . PMID   25273382.
  11. ↑ Han, Jian; Conway Morris, Simon; Ou, Qiang; Shu, Degan; Huang, Hai (2017). "Meiofaunal deuterostomes from the basal Cambrian of Shaanxi (China)". Nature. 542 (7640): 228–231. Bibcode:2017Natur.542..228H. doi:10.1038/nature21072. PMID   28135722. S2CID   353780.
  12. ↑ Liu, Yunhuan; Carlisle, Emily; Zhang, Huaqiao; Yang, Ben; Steiner, Michael; Shao, Tiequan; Duan, Baichuan; Marone, Federica; Xiao, Shuhai; Donoghue, Philip C. J. (2022-08-17). "Saccorhytus is an early ecdysozoan and not the earliest deuterostome". Nature. 609 (7927): 541–546. Bibcode:2022Natur.609..541L. doi:10.1038/s41586-022-05107-z. hdl: 1983/454e7bec-4cd4-4121-933e-abeab69e96c1 . ISSN   1476-4687. PMID   35978194. S2CID   251646316.
  13. 1 2 Mussini, G.; Smith, M. P.; Vinther, J.; Rahman, I. A.; Murdock, D. J. E.; Harper, D. A. T.; Dunn, F. S. (2024). "A new interpretation of Pikaia reveals the origins of the chordate body plan". Current Biology. 34 (13): 2980–2989.e2. doi: 10.1016/j.cub.2024.05.026 . PMID   38866005.
  14. 1 2 Caron, Jean-Bernard (June 2005). "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.
  15. ↑ Briggs; et al. (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 .
  16. ↑ Lacalli, Thurston C. (2002). "Vetulicolians—are they deuterostomes? chordates?". BioEssays. 24 (3): 208–211. doi:10.1002/bies.10064. PMID   11891757.
  17. 1 2 3 4 5 6 Aldridge, Richard J.; Hou, Xian-guang; Siveter, David J.; Siveter, Derek J.; Sarah E., Gabbott (2007). "The systematics and phylogenetic relationships of vetulicolians". Palaeontology. 50: 131–168. doi:10.1111/j.1475-4983.2006.00606.x. S2CID   85722738.
  18. ↑ Liu, Junping; Chen, Ailin; Li, Binglin; Tang, Feng; Zhao, Jiangtai; Chen, Ke (6 October 2024). "Problematic Ediacaran sail-shaped fossils from eastern Yunnan, China". Historical Biology: 1–7. doi:10.1080/08912963.2024.2403588.
  19. ↑ 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.
  20. ↑ Chen, Feng, Ma, Li (2003). "A New Vetulicolian from the Early Cambrian Chengjiang Fauna in Yunnan of China". Acta Geologica Sinica. 77 (3): 281–287. doi:10.1111/j.1755-6724.2003.tb00742.x. S2CID   128895860.{{cite journal}}: CS1 maint: multiple names: authors list (link)
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