Heteromorphus

Last updated

Heteromorphus
Temporal range: Cambrian Stage 3
Heteromorphus longicaudatus.jpg
Artist's reconstruction of Heteromorphus longicaudatus
(with much smaller "Form A" above it)
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Clade?:† Vetulicolia
Class:† Banffozoa
Order:† Banffiata
Family:† Banffiidae
Genus:† Heteromorphus
Luo and Hu in Luo et al. 1999
Type species
†Heteromorphus longicaudatus
Luo and Hu in Luo et al. 1999
Species
  • †Heteromorphus confususChen and Zhou, 1997

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. [1] 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. [2]

Contents

Description

Like Banffia, Heteromorphus has a two-part body with a notable constriction between the parts, and a crossover that effectively reverses the dorsal and ventral sides between the anterior and posterior sections. [3] The posterior portion is segmented, although the common presence of wrinkling makes counting the segments difficult. The anterior body shape ranges from torpedo-like to more rectangular, with a near-vertical anterior edge. [1]

Heteromorphus is separated from Banffia by the presence of a lateral groove, similar to that found in the Vetulicolida. [1] However, while a 2004 description claimed that four gill openings were present in the groove, later workers have not observed them. The lack of visible gills in banffiids has been speculated to indicate a burrowing lifestyle. [4] A partial "twist" has been described in Heteromorphus, compared to the well-developed torsion in Banffia. [5] While the initial description of H. confusus indicated an anus halfway along the ventral surface of the posterior section, [6] later descriptions confirmed the terminal location of the anus. [7]

Taxonomy

Heteromorphus has been grouped with Banffia and Skeemella in the family Banffiidae. [8]

The following cladogram is simplified from Mussini et al. (2024), using the definition of Vetulicolidae from Li et al. (2018). It shows Heteromorphus as part of the earliest steps, corresponding to the class Banffozoa, in the evolutionary grade leading to extant chordates. [9]

Chordata
(total group)
"Banffozoa"
"Vetulicolida"

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: [5]

Vetulicolia†

Vetulicola †

Beidazoon †

Ooedigera †

Pomatrum † / Xidazoon †

Didazoon †

Yuyuanozoon †

Banffia †

Heteromorphus†

Nesonektris †

Tunicata

H. confusus vs H. longicaudatus

H. confusus was originally described as Banffia confusa in 1997, while H. longicaudatus was described and assigned to the new genus Heteromorphus in 1999. The discoverers of B. confusa referred to it as H. confusus in 2002, accepting its assignment to Heteromorphus and, according to a comprehensive 2007 review of vetulicolian phylogenetics, indicating that H. longicaudatus is its junior synonym. However, the same review also noted substantial variation among Heteromorphus specimens, and that more species (including a distinct H. longicaudatus) may exist. [1]

Related Research Articles

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

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

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>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

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.

<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.

<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, with it mostly being considered to be a member of the enigmatic phylum Vetulicolia.

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

Vetulicolida is a class of vetulicolians. It consists of the order Vetulicolata and the genus Nesonektris, which is of uncertain placement. It is distinguished from the Banffozoa by the number and size of posterior segments as well as features of the anterior section.

<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">Didazoonidae</span> Extinct Cambrian family of vetulicolid animals

Didazoonidae is a vetulicolian family within the order Vetulicolata. It is characterized 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.

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

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.

<i>Yuyuanozoon</i> Cambrian genus of animals

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.

<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>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>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>Vetulocystis</i> Genus of vetulocystids

Vetulocystis is an extinct genus type genus of the family Vetulocystidae. It was found in the Maotianshan Shales, which date to roughly 518 mya.

Cheungkongella is a fossil organism from the lower Cambrian Chengjiang lagerstatte, the affinity of which has been the subject of debate. It was announced as a "probable" tunicate while noting the lack of definitive Cambrian fossils from that group. However, this affinity was later disputed in a paper announcing the discovery of Shankouclava, also from Chengjiang, as the oldest known tunicate. Cheungkongella has been accepted as a distinct taxon and possible tunicate by multiple workers not involved in its discovery, but the dispute remains unresolved.

Thylacocercus is a genus of vetulocystid from the Wheeler Shale of Utah that is tentatively placed withini the family Vetulocystidae. Its discovery extended the temporal range of vetulocystids from the Lower Cambrian Stage 3 to the Middle Cambrian Stage 5 (Drumian), and the geographic range from South China to Laurentia.

References

Works cited

  • 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.
  • Chen, Junyuan; Zhou, Guiqing (1997). "Biology of the Chengjiang fauna". Bulletin of the National Museum of Natural Science. 10: 11–105.
  • Conway Morris, Simon; Halgedahl, Susan L.; Selden, Paul; Jarrard, Richard D. (2015). "Rare primitive deuterostomes from the Cambrian (Series 3) of Utah" (PDF). Journal of Paleontology. 89 (4): 631–636. doi:10.1017/jpa.2015.40.
  • García-Bellido, Diego C.; Lee, Michael S. Y.; Edgecombe, Gregory D.; Jago, James B.; Gehling, James G.; 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.
  • Hou, Xian-guang; Siveter, David J.; Siveter, Derek J.; Aldridge, Richard J.; Cong, Pei-yun; Gabbott, Sarah; Ma, Xiao-ya; Purnell, Mark A.; Williams, Mark (2017). "Vetulicolians". The Cambrian Fossils of Chengjiang, China: The Flowering of Early Animal Life (2 ed.). pp. 272–281. doi:10.1002/9781118896372.ch25.
  • Li, Yujing; Williams, Mark; Gabbott, Sarah E.; Chen, Ailen; Cong, Peiyun; Hou, Xianguang (2018). "The enigmatic metazoan Yuyuanozoon magnificissimi from the early Cambrian Chengjiang Biota, Yunnan Province, South China". Journal of Paleontology. 92 (6): 1081–1091. doi:10.1017/jpa.2018.18.
  • 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.
  • Shu, Degan (2005). "On the Phylum Vetulicolia". Chinese Science Bulletin. 50 (20): 2342–2354. Bibcode:2005ChSBu..50.2342S. doi:10.1007/BF03183746. S2CID   86827605.
This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.