Marrellomorpha

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Marrellomorpha
Temporal range:
Middle Cambrian - Early Devonian, 508–390  Ma
Marrella.png
Life restoration of Marrella from the Burgess Shale
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Arthropoda
Class: Marrellomorpha
Beurlen, 1930
Subgroups

Marrellomorpha are an extinct group of arthropods known from the Cambrian to the Early Devonian. [1] They lacked mineralised hard parts, so are only known from areas of exceptional preservation, limiting their fossil distribution. The best known member is Marrella , with thousands of specimens found in the Cambrian aged Burgess Shale of Canada. The group is divided up into two major orders, Marrellida and Acercostraca. Marrellida is recognised by the possession of head shields with two or three pairs of elongate spine-like projections, and three pairs of uniramous appendages on the cephalon, while Acercostraca generally have large ovoid carapaces that cover the entire upper half of the body, and five pairs of uniramous cephalic appendages. Both groups have unbranched antennules and a segmented trunk with biramous appendages. [2] Recent research has suggested the previously enigmatic Cambrian trilobite-like arthropods Skania and Primicaris belong to this group. [3] [2] Their phylogenetic position is uncertain, various studies have alternatively placed them in the Arachnomorpha as relatives of Artiopoda (trilobites and kin), as related to Mandibulata, or as stem group euarthropods. [2] Some authors have proposed that they may be closely related to sea spiders (Pycnogonida) within Chelicerata though the cladistical support for such a relationship is relatively weak. [2]

Contents

Taxonomy

After Moysiuk et al., 2022. [2]

Fragmentary taxa assigned to Marrellomorpha include Austromarrella from Cambrian Series 3 aged deposits in Australia, [4] and Dyrnwynia from the Ordovician (Darriwilian) aged Llanfallteg Formation of Wales, which in its original description was assigned to Marrelida. [5]

Phylogeny

After Legg, 2016. [6]

Outgroups

Marrellomorpha

After Moysiuk et al., 2022. [2]

Taxa usually not
considered marrellomorphs

Related Research Articles

<i>Marrella</i> Extinct genus of Arthropods

Marrella is an extinct genus of marrellomorph arthropod known from the Middle Cambrian of North America and Asia. It is the most common animal represented in the Burgess Shale of British Columbia, Canada, with tens of thousands of specimens collected. Much rarer remains are also known from deposits in China.

<i>Skania</i> Extinct genus of arthropods

Skania is a Cambrian fossil arthropod. The type species, S. fragillis, is known from the Burgess Shale of British Columbia, Canada. A second possible species "S." sundbergi is known from the Kaili Formation of China, but its placement within the genus has been questioned.

<i>Sidneyia</i> Extinct genus of arthropods

Sidneyia is an extinct arthropod known from fossils found from the Early to the Mid Cambrian of China and the Mid Cambrian Burgess Shale of British Columbia, Canada.

<span class="mw-page-title-main">Dinocaridida</span> Extinct class of basal arthropods

Dinocaridida is a proposed fossil taxon of basal arthropods, which flourished during the Cambrian period and survived up to Early Devonian. Characterized by a pair of frontal appendages and series of body flaps, the name of Dinocaridids refers to the suggested role of some of these members as the largest marine predators of their time. Dinocaridids are occasionally referred to as the 'AOPK group' by some literatures, as the group compose of Radiodonta, Opabiniidae, and the "gilled lobopodians" Pambdelurion and Kerygmachelidae. It is most likely paraphyletic, with Kerygmachelidae and Pambdelurion more basal than the clade compose of Opabiniidae, Radiodonta and other arthropods.

<span class="mw-page-title-main">Cheiruridae</span> Extinct family of trilobites

Cheiruridae is a family of phacopid trilobites of the suborder Cheirurina. Its members, as with other members of the suborder, had distinctive pygidial modified into finger-like spines. They first appeared in the uppermost Cambrian, and persisted until the end of the Middle Devonian (Givetian). Currently about 657 species assigned to 99 genera are included.

<i>Waptia</i> Cambrian arthropod

Waptia is an extinct genus of arthropod from the Middle Cambrian of North America. It grew to a length of 6.65 cm (3 in), and had a large bivalved carapace and a segmented body terminating into a pair of tail flaps. It was an active swimmer and likely a predator of soft-bodied prey. It is also one of the oldest animals with direct evidence of brood care. Waptia fieldensis is the only species classified under the genus Waptia, and is known from the Burgess Shale Lagerstätte of British Columbia, Canada. Specimens of Waptia are also known from the Spence Shale of Utah, United States.

<i>Schinderhannes bartelsi</i> Extinct species of radiodont

Schinderhannes bartelsi is a species of hurdiid radiodont (anomalocaridid), known from one specimen from the Lower Devonian Hunsrück Slates. Its discovery was astonishing because the latest definitive radiodonts were known only from the Early Ordovician, at least 66 million years earlier than this taxon.

<i>Isoxys</i> Genus of extinct arthropods

Isoxys is a genus of extinct bivalved Cambrian arthropod; the various species of which are thought to have been freely swimming predators. It had a pair of large spherical eyes, and two large frontal appendages used to grasp prey.

<i>Primicaris</i> Extinct Genus of Cambrian Arthropod

Primicaris is genus of Cambrian arthropod from the Chengjiang biota of China and the Burgess Shale of Canada. It contains a single described species, P. larvaformis.

<span class="mw-page-title-main">Radiodonta</span> Extinct order of basal arthropods

Radiodonta is an extinct order of stem-group arthropods that was successful worldwide during the Cambrian period. They may be referred to as radiodonts, radiodontans, radiodontids, anomalocarids, or anomalocaridids, although the last two originally refer to the family Anomalocarididae, which previously included all species of this order but is now restricted to only a few species. Radiodonts are distinguished by their distinctive frontal appendages, which are morphologically diverse and used for a variety of functions. Radiodonts included the earliest large predators known, but they also included sediment sifters and filter feeders. Some of the most famous species of radiodonts are the Cambrian taxa Anomalocaris canadensis, Hurdia victoria, Peytoia nathorsti, Titanokorys gainessii, Cambroraster falcatus and Amplectobelua symbrachiata. The later surviving members include the subfamily Aegirocassisinae from the Early Ordovician of Morocco and the Early Devonian member Schinderhannes bartelsi from Germany.

<i>Mollisonia</i> Extinct genus of Ancient Arthropod

Mollisonia is an extinct genus of Cambrian arthropod. Species are known from the Burgess Shale, Langston Formation, and Wheeler Shale of North America, as well as the Chengjiang Biota of China. Twenty-one specimens of Mollisonia are known from the Greater Phyllopod bed, where they comprise less than 0.1% of the community. Remains possibly attributable to the genus are also known from the Ordovician Fezouata Formation of Morocco and Bøggild Fjord Formation in Greenland. An observation published in 2019 suggests this genus is a basal chelicerate, closer to crown group Chelicerata than members of Habeliida. It is suggested to be closely related to Corcorania, Urokodia, and Thelxiope, which together form the clade Mollisoniida, which are thought to be closely related to Chelicerata.

<span class="mw-page-title-main">Fezouata Formation</span> Geological formation in Morocco

The Fezouata Formation or Fezouata Shale is a geological formation in Morocco which dates to the Early Ordovician. It was deposited in a marine environment, and is known for its exceptionally preserved fossils, filling an important preservational window beyond the earlier and more common Cambrian Burgess shale-type deposits. The fauna of this geological unit is often described as the Fezouata biota, and the particular strata within the formation which exhibit exceptional preservation are generally termed the Fezouata Lagerstätte.

<i>Stanleycaris</i> Extinct genus of basal hurdiid radiodonts

Stanleycaris is an extinct, monotypic genus of hurdiid radiodont from the middle Cambrian (Miaolingian). The type species is Stanleycaris hirpex. Stanleycaris was described from the Stephen Formation near the Stanley Glacier and Burgess Shale locality of Canada, as well as Wheeler Formation of United States. The genus was characterized by the rake-like frontal appendages with robust inner spines.

<i>Mimetaster</i> Extinct genus of arthropods

Mimetaster is an extinct genus of marrellomorph arthropod. The type species, Mimetaster hexagonalis is known from the Lower Devonian (Pragian-Emsian) Hunsrück Slate, and amongst the most common arthropods from the locality, with over 120 specimens including three juveniles.

<i>Austromarrella</i> Extinct genus of arthropods

Austromarrella is an extinct genus of marrellomorph arthropod known from the Middle Cambrian of Australia.

<i>Furca</i> (genus) Extinct genus of arthropods

Furca is an extinct genus of marrellomorph arthropod known from the Sandbian stage of the Czech Republic, with a single currently described species, Furca bohemica. A tentative additional species, "Furca mauretanica": was proposed for specimens discovered in Morocco, but this species remains a nomen nudum until formally published, and probably belongs in a new separate genus.

<span class="mw-page-title-main">Hurdiidae</span> Extinct family of arthropods

Hurdiidae is an extinct cosmopolitan family of radiodonts, a group of stem-group arthropods, which lived during the Paleozoic Era. It is the most long-lived radiodont clade, lasting from the Cambrian period to the Devonian period.

This list of fossil arthropods described in 2019 is a list of new taxa of trilobites, fossil insects, crustaceans, arachnids and other fossil arthropods of every kind that are scheduled to be described during the year 2019, as well as other significant discoveries and events related to arthropod paleontology that are scheduled to occur in the year 2019.

<i>Tomlinsonus</i> Extinct genus of marellomorph

Tomlinsonus is an extinct genus of marellomorph arthropod known from the Late Ordovician (Katian) Kirkfield Formation of Ontario, Canada. It is a member of Marellida, and closely related to Mimetaster.

<i>Zhenghecaris</i> Genus of enigmatic Cambrian arthropod

Zhenghecaris shankouensis is an enigmatic arthropod from the Lower Cambrian Maotianshan Shales, either classified as a hurdiid or thylacocephalan. It is known from several specimens mostly preserving the carapace and eyes measuring roughly 15 cm (5.9 in), which mark it as one of the largest thylacocephalans, behind Ostenocaris, Dollocaris and Ainiktozoon, as well as the earliest since all other thylacocephalans are Ordovician or younger. Since no appendages have been preserved, the fossil may not be a thylacocephalan, with a hurdiid affinity being suggested instead, due to its resemblance to the H-element of genera such as Cambroraster. It has also been suggested to be within Arthropoda incertae sedis, as the fragmentary remains cannot confidently be classified further.

References

  1. Rak, Š. P. N. (2011). "A revision of the Late Ordovician marellomorph arthropod Furca bohemica from Czech Republic". Acta Palaeontologica Polonica. doi: 10.4202/app.2011.0038 .
  2. 1 2 3 4 5 6 Moysiuk, Joseph; Izquierdo-López, Alejandro; Kampouris, George E.; Caron, Jean-Bernard (July 2022). "A new marrellomorph arthropod from southern Ontario: a rare case of soft-tissue preservation on a Late Ordovician open marine shelf". Journal of Paleontology. 96 (4): 859–874. doi:10.1017/jpa.2022.11. ISSN   0022-3360.
  3. Legg, D.A. (2015-09-30). "The morphology and affinities of Skania fragilis (Arthropoda) from the middle Cambrian Burgess Shale". Bulletin of Geosciences: 509–518. doi: 10.3140/bull.geosci.1532 . ISSN   1802-8225.
  4. Haug, Joachim (2012). "A new link between Orsten-type assemblages and the Burgess Shale—a Marrella-like arthropod from the Cambrian of Australia". Acta Palaeontologica Polonica. doi: 10.4202/app.2011.0120 .
  5. Legg, David (2016). "A new marrellid arthropod from the Ordovician of Wales". Acta Palaeontologica Polonica. 61. doi: 10.4202/app.00246.2016 . ISSN   0567-7920.
  6. Legg, David A. (2016-02-27). "An acercostracan marrellomorph (Euarthropoda) from the Lower Ordovician of Morocco". The Science of Nature. 103 (3): 21. doi:10.1007/s00114-016-1352-5. ISSN   1432-1904.