A chordate is a deuterostomal bilaterian 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.
Vetulicolia is a group of bilaterian marine animals encompassing several extinct species from the Cambrian, and possibly Ediacaran, periods. As of 2023, the majority of workers favor placing Vetulicolians in the stem group of the Chordata, but some continue to favor a more crownward placement as a sister group to the Tunicata. It was initially erected as a monophyletic clade with the rank of phylum in 2001, with subsequent work supporting its monophyly. However, more recent research suggests that vetulicolians may be paraphyletic and form a basal evolutionary grade of stem chordates.
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.
Pikaia gracilens is an extinct, primitive chordate marine animal known from the Middle Cambrian Burgess Shale of British Columbia. Described in 1911 by Charles Doolittle Walcott as an annelid, and in 1979 by Harry B. Whittington and Simon Conway Morris as a chordate, it became "the most famous early chordate fossil", or "famously known as the earliest described Cambrian chordate". It is estimated to have lived during the latter period of the Cambrian explosion. Since its initial discovery, more than a hundred specimens have been recovered.
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.
Didazoon haoae is an extinct species of vetulicolid vetulicolian described by Shu, et al. based on fossils found in the Qiongzhusi (Chiungchussu) Formation, Yu'anshan Member, Lower Cambrian, in the Dabanqiao area (Kunming), about 60 km northwest of Chengjiang, China.
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.
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, with it mostly being considered to be a member of the enigmatic phylum Vetulicolia.
Vetulicolidae is a vetulicolian family from the Cambrian Stage 3 Maotianshan Shale and Sirius Passet Lagerstätte that consists of Vetulicola, Beidazoon, and Ooedigera. It is distinguished from the Didazoonidae by a harder body wall and the lack of an oral disc.
Didazoonidae is a vetulicolian family within the order Vetulicolata. It is charaterized by a relatively thin-walled, non-biomineralized body and a large, round anterior opening surrounded by an oral disc. It may be paraphyletic, even if the phylum Vetulicolia is monophyletic.
Banffozoa is an extinct class of bilaterians. Most workers place it in the Vetulicolia, but the protostome-like features of some members have motivated ongoing debate. Banffozoa consists of the order Banffiata as well as a dwarf "Form A" that has not been formally described or named. Skeemella has been placed incertae sedis in this class, but has more recently been placed with the Banffiidae. Banffozoa may be paraphyletic even if Vetulicolia is monophyletic.
Yuyuanozoon magnificissimi, from the Cambrian Stage 3 Chengjiang lagerstatte, is the largest known vetulicolian, with specimens up to 20 cm in length compared to 5–14 cm for other vetulicolian species.
Vetulicola cuneata is a species of extinct marine 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.
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.
Skeemella is a genus of elongate animal from the Middle Cambrian Wheeler Shale and Marjum lagerstätte of Utah. It has been classified with the banffozoan vetulicolians.
Nesonektris aldridgei is an extinct vetulicolian 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.
Beidazoon venustum is a marine deuterostome from the group Vetulicolia. It originates from the lower Cambrian Chengjiang biota of Yunnan Province, China, and was discovered in 2005. It is known as the smallest described vetulicolian, and for its surface being covered in many small nodes.
Banfiidae is a family of extinct banffozoan animals from North America and China. The family name is sometimes spelt Banffidae. It includes Banffia, Heteromorphus, and possibly Skeemella. The family may be paraphyletic. The family may be paraphyletic. A Heteromorphus-like dwarf "Form A" is allied with this group at the class level, but has not been formally described or assigned to this family.
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.
Heteromorphus is an extinct genus of banffiid from the lower Cambrian Chengjiang lagerstatte. It contains one broadly accepted species, Heteromorphus confusus, as well as a proposed junior synonym, Heteromorphus longicaudatus that may prove to be a separate species as additional specimens are examined. A much smaller species labeled "Form A" is allied with Heteromorphus at the class level but has not been formally described or assigned to Heteromorphus itself.
