Diplacanthus

Last updated

Diplacanthus
Temporal range: Eifelian–Famennian
Diplacanthus striatus fossil fish (Lower Devonian; Scotland) (15149695488).jpg
Fossil specimen of D. crassissimus (=D. striatus)
Diplacanthus.png
Life restoration
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Acanthodii
Order: Diplacanthiformes
Family: Diplacanthidae
Genus: Diplacanthus
Agassiz, 1843
Species

see text

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

Contents

Classification

The genus was named by Louis Agassiz in 1843. [1] It was formerly regarded as belonging to the Climatiformes but recently reassigned to the Diplacanthiformes, in which it is united with, amongst others, Rhadinacanthus, Uraniacanthus , and Culmacanthus . Diplacanthiforms were widespread during the Middle and early Late Devonian. They are best represented in the Middle Devonian, by articulated fossils, fin spines, and abundant scales, the latter particularly from northern Europe. [2]

In a latest revision of the genus Diplacanthus, a large number of species from Europe were synonymized with earlier Scottish species, and these too were redefined. D. crassisimus was taken to have precedence over D. striatus as the name of the type specimen. Diplacanthus longispinus was reassigned to Rhadinacanthus longispinus, within which were also included Diplacanthus horridus (Woodward, 1892) and Diplacanthus ellsi. Diplacanthus tenuistriatus and Diplacanthus kleesmentae were however retained. Non-Laurussian species such as Diplacanthus acus from South Africa were not considered in this review. [2]

Species

Diplacanthus acus (acanthodian fish) from Waterloo Farm.jpg
Fossil (left) and life restoration of D. acus
Diplacanthus reconstructed.jpg

Diplacanthus acus is described from a near complete whole-bodied impression discovered in 1999 during roadworks cutting the Waterloo Farm lagerstätte in South Africa. [3] The type specimen of Diplacanthus acus is approximately 100 mm long and has exceptionally long and thin ribbed spines. The intermediate spines are, conversely, extremely reduced. [4] Unusually it preserves complete outlines of many of the fins.

Diplacanthus is most commonly associated with deposits traditionally interpreted as fresh water. However, Waterloo Farm is interpreted as estuarine in origin, as is the Canadian Miguashaia lagerstätte from which two species of Diplacanthus have been described. [5] The description of Diplacanthus acus provided the first record of a diplacanthid from the Famennian, with diplacanthids having previously been thought to have gone extinct by the end of the Frasnian. [6]

Related Research Articles

<span class="mw-page-title-main">Acanthodii</span> Paraphyletic group of cartilaginous fishes

Acanthodii or acanthodians is an extinct class of gnathostomes. They are currently considered to represent a paraphyletic grade of various fish lineages basal to extant Chondrichthyes, which includes living sharks, rays, and chimaeras. Acanthodians possess a mosaic of features shared with both osteichthyans and chondrichthyans. In general body shape, they were similar to modern sharks, but their epidermis was covered with tiny rhomboid platelets like the scales of holosteians.

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

Hyneria is a genus of large prehistoric predatory lobe-finned fish which lived in fresh water during the Famennian stage of the Devonian period.

<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.

The Climatiiformes is an order of extinct fish belonging to the class Acanthodii. Like most other "spiny sharks", the Climatiiformes had sharp spines. These animals were often fairly small in size and lived from the Late Silurian to the Early Carboniferous period. The type genus is Climatius. The order used to be subdivided into the suborders Climatiida and Diplacanthida, but subsequently Diplacanthida has been elevated to a separate order, the Diplacanthiformes. The Diplacanthiformes take their name from Diplacanthus, first described by Agassiz in 1843. Family Gyracanthidae is sometimes rejected from this order.

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

The South African National Roads Agency SOC Ltd or SANRAL is a South African parastatal responsible for the management, maintenance and development of South Africa's proclaimed National Road network which includes many National ("N") and some Provincial and Regional ("R") route segments.

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

Gyracanthides is an extinct genus of acanthodian gnathostome, known from Devonian to Early Carboniferous.

<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.

<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.

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

Amelacanthus is an extinct genus of elasmobranchian cartilaginous fish from the Paleozoic era. It is known from fin spines and currently contains four described species. It is known from the Permian and Carboniferous of North America, Europe, and Africa. It is also known from the Famennian of Russia. Possible specimens of Amelacanthus were found in Permian (Wordian) sediments of Oman.

<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>Isityumzi</i> Extinct genus of lungfish

Isityumzi mlomomde is fossil lungfish described from fragmentary remains including one complete parasphenoid, tooth plates fragments and scales from the Late Devonian Sarcopterygians. It represents the only record of Late Devonian lungfish remains from western Gondwana.

<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

  1. "Diplacanthus". The Paleaobiology Database.
  2. 1 2 Burrow, Carole; Blaauwen, Jan den; Newman, Michael; Davidson, Robert. "The diplacanthid fishes (Acanthodii, Diplacanthiformes, Diplacanthidae) from the Middle Devonian of Scotland". Palaeontologia Electronica. 19 (1): 1–83. doi: 10.26879/601 . ISSN   1094-8074.
  3. Gess, Robert W. and Whitfield Alan K. (2020). "Estuarine fish and tetrapod evolution: Insights from a Late Devonian (Famennian) Gondwanan estuarine lake and a southern African Holocene equivalent". Biological Reviews. doi:10.1111/brv.12590. PMID   32059074
  4. Gees, Robert W. (2001-01-01). "A new species of Diplacanthus from the Late Devonian (Famennian) of South Africa". Annales de Paléontologie. 87 (1): 49–60. doi:10.1016/S0753-3969(01)88002-2. ISSN   0753-3969.
  5. Gess, R. and Coates M. (2008). Vertebrate Diversity of the Late Devonian (Famennian) Deposit near Grahamstown, South Africa. Journal of Vertebrate Paleontology: 28 (3) conference supplement p 83.
  6. Janvier, P.(1996). Early Vertebrates. Oxford University Press, Oxford.