Didazoonidae

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Didazoonidae
Temporal range: Cambrian Stage 3
Artists' reconstructions of Didazoonids
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Clade?: Vetulicolia
Class: Vetulicolida
Order: Vetulicolata
Family: Didazoonidae
Shu and Han in Shu et al. 2001
Type genus
Didazoon
Shu and Han in Shu et al. 2001
Genera

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. [1] [2] It may be paraphyletic, [3] even if the phylum Vetulicolia is monophyletic. [4]

Contents

Description

Didazoonids have an ovoid to subquadrate anterior section divided into six subdivisions marked by five circumventing lines perpendicular to the body axis. Cowl-shaped lateral pouches appear along each side of the anterior section, coincident with the five dividing lines. The anterior opening is large, round, and surrounded by a circumventing oral disc. The posterior section has seven segments, which in some species each carry up to six annulations. [2]

Taxonomy

Didazoonidae was erected to group Didazoon . Xidazoon . and Pomatrum , although Xidazoon has since been shown to be a junior synonym of Pomatrum. [1] Yuyuanozoon was moved to the Didazoonidae after additional specimens illuminated more details of the anterior opening and posterior segment annulations. [5]

Nesonektris has also been assigned to Didazoonidae by some workers, [6] but this has not been widely accepted. [7] [8]

A 2024 study has found the Didazoonidae (without Nesonektris) to be a paraphyletic grade of the vetulicolians closest to crownward chordates as shown in this simplified cladogram: [3]

Chordata

An earlier study in 2014 placed vetulicolians as the sister-group to tunicates, but was unable to resolve any relationships among vetulicolians as a group: [4]

Vetulicolia

Tunicata

Related Research Articles

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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.

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

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

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<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>Didazoon</i> Cambrian age animal

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<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.

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

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.

<span class="mw-page-title-main">Banffozoa</span> Extinct Cambrian group of marine animals

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

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.

<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 animal from the Middle Cambrian Wheeler Shale and Marjum lagerstätte of Utah. It has been classified with the banffozoan vetulicolians.

<i>Cotyledion</i> Extinct genus of filter-feeders

Cotyledion tylodes is an extinct, stalked filter-feeder known from the Chengjiang lagerstatten. The living animal reached a couple of centimetres in height, and bore a loose scleritome of ovoid sclerites. Its interpretation has been controversial, but it is currently thought to be a member of the Entoprocta stem group.

<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>Nesonektris</i> Extinct genus of Cambrian Era Chordate

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.

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

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.

<span class="mw-page-title-main">Banffiidae</span> Extinct Cambrian family of animals

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.

<i>Shenzianyuloma</i> Species of vetulicolian invertebrate

Shenzianyuloma is an extinct genus of vetulicolian represented by a single species, Shenzianyuloma yunnanense, from the Maotianshan Shale during Stage 3 of the Cambrian period. It is notable for having a compact body shape akin to that of an angelfish. It's exact phylogenetic position is unclear, and it was not included in a 2024 phylogenetic analysis of vetulicolians.

Luolishania is an extinct genus of lobopodian panarthropod and known from the Lower Cambrian Chiungchussu Formation of the Chengjiang County, Yunnan Province, China. A monotypic genus, it contains one species Luolishania longicruris. It was discovered and described by Hou Xian-Guang and Chen Jun-Yuan in 1989. It is one of the superarmoured Cambrian lobopodians suspected to be either an intermediate form in the origin of velvet worms (Onychophora) or basal to at least Tardigrada and Arthropoda. It is the basis of the family name Luolishaniidae, which also include other related lobopods such as Acinocricus, Collinsium, Facivermis, and Ovatiovermis. Along with Microdictyon, it is the first lobopodian fossil discovered from China.

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

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.

References

  1. 1 2 Aldridge et al. 2007 , pp. 145–146
  2. 1 2 Li et al. 2018 , p. 1085(Note: This paper uses different terminology for vetulicolian anatomy explained on page 1082; this page uses the more common terms regardless of source)
  3. 1 2 Mussini et al. 2024 , pp. 6–7(Note: The cladogram is simplified using the definition of Vetulicolidae from Li et al. 2018, cited elsewhere on this page)
  4. 1 2 García-Bellido et al. 2014 , p. 9
  5. Li et al. 2018 , p. 1082
  6. Li et al. 2018 , p. 1084
  7. "†Nesonektris García-Bellido et al. 2014". Paleobiology Database. Retrieved December 8, 2024.
  8. "†family Didazoonidae Shu and Han 2001". Paleobiology Database. Retrieved December 8, 2024.

Works cited