Heteromorphus

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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†

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

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<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

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<i>Didazoon</i> Cambrian age animal

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<i>Pomatrum</i> Cambrian age animal

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<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">Vetulicolidae</span> Extinct Cambrian family of vetulicolian animals

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

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

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

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<span class="mw-page-title-main">Kunmingella</span>

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

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

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<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.

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.

References

Works cited

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  • 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.
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