Isityumzi

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Isityumzi
Temporal range: Famennian
Palaeozoic Lungfish Parasphenoid Morphology.jpg
Parasphenoid material (A-D) compared to other fossil lungfish
Gessetal2023 Isityumzi reconstruction.png
Life restoration
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Clade: Sarcopterygii
Class: Dipnoi
Genus: Isityumzi
Gess & Clement, 2019
Species:
I. mlomomde
Binomial name
Isityumzi mlomomde
Gess & Clement, 2019

Isityumzi mlomomde is fossil lungfish described from fragmentary remains including one complete parasphenoid, tooth plates fragments and scales from the Late Devonian Sarcopterygians (lobe finned fishes). [1] It represents the only record of Late Devonian lungfish remains from western Gondwana. [1]

Contents

This novel species was described through an international collaboration from the world renowned Waterloo Farm lagerstätte in the former Grahamstown (Makhanda) of the Eastern Cape province, South Africa. The type material for this genus was excavated from a layer of black metashale located in a predominantly arenaceous Witpoort Formation corresponding to the Famennian age.

Lungfish are believed to have solely originated from tropical to warm temperate regions, however, evidence from the Isityumzi mlomomde adds a bigger circle of information to the current perception as evidence from these now suggests that lungfishes originated from the high palaeolatitude fauna located at 70° latitude and possibly further south. [2] [3] This was the position of now Waterloo Farm lagerstätte in what was once Gondwana landmass.

Isityumzi mlomomde is further believed to have coexisted with the tetrapods of the Famennian in an estuarine ecosystem environment as seen through the Waterloo Farm lagerstätte's geological lens. [4] [5] [6]

Description

To date, two parasphenoid bones have been found in Waterloo Farm, one partial and the other (latest) complete. [1] The current description is mainly based on the complete specimen found with other fragments, as the incomplete one has already been described previously. [1] [7]

The parasphenoid of the Isityumzi mlomomde is thin and flat, not fused with the pterygoids but shows a clear area for overlap by these bones. The size difference across the widest point between the holotype and the partial parasphenoid is 16 mm (0.63 in), with the former being smaller. The anterior part is wide, with almost half the entire length of the total specimen. The parasphenoid has a distinctly broad rhombic anterior portion (corpus) and a narrow posterior shaft. The shaft is slender with parallel sides that taper to a single point posteriorly. The lateral angle between the stalk and the corpus is 30°. A long median ridge runs anteroposteriorly carrying a broad channel across the length of the stalk but it is unclear whether or not this lies on the dorsal or ventral surface. The overall appearance of the bones resembles those of Oervigia .

Etymology

The genus name Isityumzi is derived from the IsiXhosa language meaning 'device for crushing'. The species epithet mlomomde is also an IsiXhosa name meaning 'long mouthed'. [1]

Related Research Articles

<span class="mw-page-title-main">Devonian</span> Fourth period of the Paleozoic Era 419–359 million years ago

The Devonian is a geologic period and system of the Paleozoic era during the Phanerozoic eon, spanning 60.3 million years from the end of the preceding Silurian period at 419.2 million years ago (Ma), to the beginning of the succeeding Carboniferous period at 358.9 Ma. It is named after Devon, South West England, where rocks from this period were first studied.

<span class="mw-page-title-main">Sarcopterygii</span> Class of fishes

Sarcopterygii — sometimes considered synonymous with Crossopterygii — is a taxon of the bony fish known as the lobe-finned fish or sarcopterygians, characterised by prominent muscular limb buds (lobes) within the fins, which are supported by articulated appendicular skeletons. This is in contrast to the other clade of bony fish, the Actinopterygii, which have only skin-covered bony spines (lepidotrichia) supporting the fins.

<span class="mw-page-title-main">Rhipidistia</span> Clade of vertebrates

Rhipidistia, also known as Dipnotetrapodomorpha, is a clade of lobe-finned fishes which includes the tetrapods and lungfishes. Rhipidistia formerly referred to a subgroup of Sarcopterygii consisting of the Porolepiformes and Osteolepiformes, a definition that is now obsolete. However, as cladistic understanding of the vertebrates has improved over the last few decades, a monophyletic Rhipidistia is now understood to include the whole of Tetrapoda and the lungfishes.

<i>Hyneria</i> Extinct genus of tetrapodomorphs from the Devonian

Hyneria is a genus of large prehistoric predatory lobe-finned fish which lived in freshwater during the Devonian period (Famennian).

<i>Bothriolepis</i> Diverse genus of placoderm fishes of the Devonian

Bothriolepis was a widespread, abundant and diverse genus of antiarch placoderms that lived during the Middle to Late Devonian period of the Paleozoic Era. Historically, Bothriolepis resided in an array of paleo-environments spread across every paleocontinent, including near shore marine and freshwater settings. Most species of Bothriolepis were characterized as relatively small, benthic, freshwater detritivores, averaging around 30 centimetres (12 in) in length. However, the largest species, B. rex, had an estimated bodylength of 170 centimetres (67 in). Although expansive with over 60 species found worldwide, comparatively Bothriolepis is not unusually more diverse than most modern bottom dwelling species around today.

<i>Groenlandaspis</i> Genus of fishes (fossil)

Groenlandaspis is an extinct genus of arthrodire from the Late Devonian. Fossils of the different species are found in late Devonian strata in all continents except eastern Asia. The generic name commemorates the fact that the first specimens of the type species were found in Greenland.

<i>Eusthenodon</i> Extinct genus of tetrapodomorphs

Eusthenodon is an extinct genus of tristichopterid tetrapodomorphs from the Late Devonian period, ranging between 383 and 359 million years ago. They are well known for being a cosmopolitan genus with remains being recovered from East Greenland, Australia, Central Russia, South Africa, Pennsylvania, and Belgium. Compared to the other closely related genera of the Tristichopteridae clade, Eusthenodon was one of the largest lobe-finned fishes and among the most derived tristichopterids alongside its close relatives Cabonnichthys and Mandageria.

<i>Gondwanascorpio</i> Extinct genus of scorpion from late Devinian Gondwana

Gondwanascorpio emzantsiensis is an extinct Gondwanan scorpion that lived 360 million years ago in the Devonian. Its fossil remains, clearly showing pincer and sting, were discovered in rocks of the Witteberg Group near Grahamstown in South Africa. At present, this scorpion is the oldest known land-dwelling animal from Gondwana, which in Devonian times was separated from Laurasia by a deep ocean. At the time, the fossil site was only 15° from the South Pole, but rather than arctic-like tundra, the region was probably wooded, providing ample insect life for food. Previously, only two scorpion species were known from the late Devonian – Hubeiscorpio gracilitarsus from China and Petaloscorpio bureaui from Canada. The species was described by Robert Gess of Wits University in the journal African Invertebrates. The specific epithet derives from umZantsi, the isiXhosa word for "south", sometimes used for South Africa.

<i>Priscomyzon</i> Extinct lamprey from late Devonian South Africa

Priscomyzon riniensis is an extinct lamprey that lived some 360 million years ago during the Famennian in a marine or estuarine environment in South Africa. This small agnathan is anatomically similar to the Mazon Creek lampreys, but is some 35 million years older. Its key developments included the first known large oral disc, circumoral teeth and a branchial basket.

<i>Serenichthys</i> Genus of coelacanth fish

Serenichthys kowiensis is a fossil species of coelacanth described in 2015 from near Grahamstown in South Africa.

<i>Antarctilamna</i> Extinct genus of Devonian shark

Antarctilamna is an extinct genus of Devonian cartilaginous fish originally exemplified by Antarctilamna prisca from South Eastern Australia and Antarctica. The latest occurring described species is Antarctilamna ultima from the Waterloo Farm lagerstätte in South Africa. Antarctilamna has robust ctenacanthid-like spines which lack a deep insertion area, and are borne in front of the first dorsal fin; in addition to distinctive diplodont teeth with small intermediate cusps. Antarctilamna-like spines, known from the Bunga Beds locality in Australia have been ascribed to A. prisca.

<i>Plesioselachus</i> Extinct genus of cartilaginous fishes

Plesioselachus is an extinct genus of Late Devonian (Famennian) cartilaginous fish with uncertain classification, which contains only one species, P. macracanthus from the Waterloo Farm lagerstätte in South Africa. Known from a single incomplete articulated skeleton and some isolated remains, it is characterized by having a long dorsal spine with length about one third of body length.

<i>Tutusius</i> Genus of extinct tetrapod from the Devonian of South Africa

Tutusius is a genus of extinct tetrapod from the Devonian of South Africa, containing a single species, Tutusius umlambo. It was described from the +/- 360 myo Gondwana locality of Waterloo Farm lagerstätte on the south-eastern coast of South Africa, which at the time was located within the Antarctic Circle. Together with the find of Umzantsia amazana from the same locality, this provides the first evidence that Devonian tetrapods were not restricted to the tropics as was formerly believed, and suggests that they may have been global in distribution. Waterloo Farm fossils have been metamorphosed and intensely flattened, with the bone tissue replaced by secondary metamorphic mica that is partially altered to kaolinite and chlorite during uplift. They also provide the first evidence of Devonian tetrapods from the continent of Africa, and only the second and third such taxa from Gondwana.

<i>Umzantsia</i> Extinct genus of limbed stegocephalians from the Devonian of South Africa

Umzantsia is an extinct genus of limbed stegocephalians from the Devonian of South Africa. It contains a single species, Umzantsia amazana. The genus is based on ~360 million year old skull and shoulder bones from the Waterloo Farm lagerstäTutusius umlambo from the same locality, this provides the first evidence that Devonian limbed vertebrates were not restricted to the tropics as was formerly believed, and suggests that they may have been global in distribution. Waterloo Farm fossils have been metamorphosed and intensely flattened, with the bone tissue replaced by secondary metamorphic mica that is partially altered to kaolinite and chlorite during uplift. They also provide the first evidence of Devonian limbed vertebrates from the continent of Africa, and only the second and third such taxa from Gondwana.

<span class="mw-page-title-main">Waterloo Farm lagerstätte</span> Site in South Africa with a wide range of fossils from high-latitudinal Gondwana

The Waterloo Farm lagerstätte is a Famennian lagerstätte in South Africa that constitutes the only known record of a near-polar Devonian coastal ecosystem.

<i>Diplacanthus</i> Extinct genus of Devonian spiny sharks.

Diplacanthus is an extinct genus of Mid to Late Devonian fish in the class Acanthodii, known as spiny sharks.

Hexachara is a genus of fossil charophyte that is likely to have formed meadows within sheltered oligohaline reaches of lakes.

<i>Naiadites</i> Extinct genus of bivalves

Naiadites is an extinct genus of thin-shelled non-marine bivalve from the Upper Carboniferous coal-measures of Nova Scotia in Canada.

<i>Octochara</i> Extinct genus of algae

Octochara is a genus of fossil charophyte from the Famennian. It is one of two genera of charophyte described from the Waterloo Farm lagerstätte in southern Africa. It and Hexachara, from the same locality provide the oldest record of reconstruct able charophytes with in situ oogonia.

<i>Hungerfordia</i> (alga) Extinct genus of algae

Hungerfordia is a genus of presumed marine algae first described by Fry and Banks in 1955 in describing Hungerfordia dichotoma from Late Devonian strata. It has been interpreted as a probable brown (Phaeophyte) algae though the possibility that it represents a red (Rhodophyte) alga is not excluded - the taxonomic challenge being that modern red and brown algae are differentiated on the basis of colour and cellular structure which are not preserved in the fossil taxa. Douglas and Jell (1985) suggested that Buthotrephis trichotoma and B. divaricata should furthermore be transferred from Buthotrephis to Hungerfordia.

References

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  2. Torsvik, Trond H.; Cocks, L. Robin M. (2011). "The Palaeozoic palaeogeography of central Gondwana". Geological Society, London, Special Publications. 357 (1): 137–166. Bibcode:2011GSLSP.357..137T. doi:10.1144/sp357.8. ISSN   0305-8719. S2CID   131031948.
  3. Torsvik, Trond H.; Cocks, L. Robin M. (2013). "Gondwana from top to base in space and time". Gondwana Research. 24 (3–4): 999–1030. Bibcode:2013GondR..24..999T. doi:10.1016/j.gr.2013.06.012.
  4. Friedman, Matt; Daeschler, Edward B. (2006). "Late Devonian (Famennian) Lungfishes from the Catskill Formation of Pennsylvania, USA". Palaeontology. 49 (6): 1167–1183. Bibcode:2006Palgy..49.1167F. doi: 10.1111/j.1475-4983.2006.00594.x . ISSN   0031-0239.
  5. Lebedev, O. A (2004). "A new tetrapod Jakubsonia livnensis from the Early Famennian (Devonian) of Russia and palaeoecological remarks on the Late Devonian tetrapod habitats". Acta Universitatis Latviensis. 679: 79–98 via dspace.lu.lv.
  6. Thomson; Panchen, KS; AL (1980). "The ecology of Devonian lobe-finned fishes. In The terrestrial environment and the origin of land vertebrates". Academic Press London. 15: 187–222.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  7. Anderson; Gess; Hiller, M.E; R.W; N (1994). "The first Bothriolepsis-associated Devonian fish fauna from Africa". South African Journal of Science. 90: 397.{{cite journal}}: CS1 maint: multiple names: authors list (link)