Lepisosteiformes

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Lepisosteiformes
Temporal range: Early Jurassic–present [1]
Kaimanfische (Lepisosteus).jpg
Florida gar (Lepisosteus platyrhynchus) (Lepisosteidae)
2013-03 Naturkundemuseum Berlin Dickschupperfisch Scheenstia maximus anagoria.jpg
Fossil of Scheenstia maximus (Lepidotidae)
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Clade: Ginglymodi
Clade: Neoginglymodi
Order: Lepisosteiformes
Hay, 1929
Families

For other genera, see text

Lepisosteiformes is an order of ray-finned fish and the only living members of the clade Ginglymodi. Its only extant representatives are the gar (family Lepisosteidae), and it is defined as all members of Ginglymodi that are more closely related to gar than to the extinct Semionotiformes, the other major grouping of ginglymodians. They are one of two extant orders in the infraclass Holostei alongside the Amiiformes (now represented by only the bowfins). [2] [1]

Contents

While represented only by the two extant genera of gar from North America, the Lepisosteiformes are an ancient group known as far back as the Early Jurassic, and formerly had a much larger range, being known from almost every continent. Considerable morphological diversity is known among extinct members compared to modern gar, from the superficially gar-like Obaichthyidae to the semionotiform-like Lepidotidae, which were previously classified in the Semionotiformes. [3] [4]

Evolution

The earliest known lepisosteiform is the marine Lepidotes from the Early Jurassic of Germany, which largely shares the original body plan of Ginglymodi shared with Semionotiformes. [1] However, phylogenetic estimates suggest that the earliest lepisosteiforms diverged from their closest relatives in the Middle Triassic. The most basal lepisosteiform is thought to be Khoratichthys from the Late Jurassic or Early Cretaceous of Thailand, which is thought to have diverged from other members of the group during the Late Triassic. [5] Other studies suggest that the most basal member is Neosemionotus from the Early Cretaceous of Argentina, which diverged from the rest of the group during the Early Jurassic. [6]

Numerous early lepisosteiforms (including basal lepisosteiforms such as Khoratichthys and Lanxangichthys, lepidotids such as Isanichthys , and basal lepisosteoids such as Thaiichthys ) are known from the Late Jurassic and Early Cretaceous of Thailand and Laos, suggesting that what is now Southeast Asia may have been an important region for early lepisosteiform evolution, and that ginglymodians were the dominant fish in freshwater ecosystems in the region at the time. [5]

It has been suggested that as is with basal ginglymodians and the Semionotiformes, the earliest lepisosteiforms were marine and independently colonized and diversified in freshwater ecosystems multiple times; first among the Lepidotidae, and then among the Lepisosteoidei. Two independent freshwater colonizations appear to have occurred among the lepisosteioids: one in Southeast Asia and one in West Gondwana. The latter included the Obaichthyidae, close relatives of the gar. [6]

The ecology of the group including extinct members broader than that of living gars. Members of Lepidotidae in particular are strongly different from modern gars in having bulky bodies, with the large (up to 2 metres (6.6 ft)) lepidotid Scheenstia developing powerful jaws filled with rounded teeth that were likely used to crush shells (durophagy). [7]

Classification

Related Research Articles

<span class="mw-page-title-main">Amiiformes</span> Order of fishes

The Amiiformes order of fish has only two extant species, the bowfins: Amia calva and Amia ocellicauda, the latter recognized as a separate species in 2022. These Amiiformes are found in the freshwater systems of North America, in the United States and parts of southern Canada. They live in freshwater streams, rivers, and swamps. The order first appeared in the Triassic, and the extinct members include both marine and freshwater species, many of which are morphologically disparate from bowfins, such as the caturids.

<span class="mw-page-title-main">Semionotiformes</span> Extinct order of fishes

Semionotiformes is an order of ray-finned fish known from the Middle Triassic (Anisian) to the Late Cretaceous (Maastrichtian). Their closest living relatives are gars (Lepisosteidae), with both groups belonging to the clade Ginglymodi within the Holostei. The group includes both freshwater (Semionotidae) and marine adapted forms. Many members of the family Macrosemiidae, have elongated dorsal fins, often associated with an adjacent area of skin which was free of scales. These fins were likely undulated for use in precision swimming. The body morphology of macrosemiids suggests that they were slow swimmers that were capable of maneuvering around complex topography, such as reef environments.

<span class="mw-page-title-main">Neopterygii</span> Subclass of fishes

Neopterygii is a subclass of ray-finned fish (Actinopterygii). Neopterygii includes the Holostei and the Teleostei, of which the latter comprise the vast majority of extant fishes, and over half of all living vertebrate species. While living holosteans include only freshwater taxa, teleosts are diverse in both freshwater and marine environments. Many new species of teleosts are scientifically described each year.

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

Lepidotes is an extinct genus of Mesozoic ray-finned fish. It has long been considered a wastebasket taxon, characterised by "general features, such as thick rhomboid scales and, for most of the species, by semi-tritorial or strongly tritorial dentition". with dozens of species assigned to it. Fossils attributed to Lepidotes have been found in Jurassic and Cretaceous rocks worldwide. It has been argued that Lepidotes should be restricted to species closely related to the type species L. gigas, which are only known from the Early Jurassic of Western and Central Europe, with most other species being not closely related, with other species transferred to new genera such as Scheenstia.Lepidotes belongs to Ginglymodi, a clade of fish whose only living representatives are the gars (Lepisosteidae). The type species L. gigas and close relatives are thought to be members of the family Lepidotidae, part of the order Lepisosteiformes within Ginglymodi, with other species occupying various other positions within Ginglymodi.

<span class="mw-page-title-main">Holostei</span> Group of bony fish

Holostei is a group of ray-finned bony fish. It is divided into two major clades, the Halecomorphi, represented by the single living genus, Amia with two species, the bowfins, as well as the Ginglymodi, the sole living representatives being the gars (Lepisosteidae), represented by seven living species in two genera. The earliest members of the clade appeared during the Early Triassic, over 250 million years ago.

Paleontology or palaeontology is the study of prehistoric life forms on Earth through the examination of plant and animal fossils. This includes the study of body fossils, tracks (ichnites), burrows, cast-off parts, fossilised feces (coprolites), palynomorphs and chemical residues. Because humans have encountered fossils for millennia, paleontology has a long history both before and after becoming formalized as a science. This article records significant discoveries and events related to paleontology that occurred or were published in the year 1830.

<span class="mw-page-title-main">Macrosemiidae</span> Extinct order of fishes

Macrosemiidae is an extinct family of ginglymodian fish. The family first appeared during the Middle Triassic and disappeared during the Late Cretaceous. The group has been found in rock formations in Africa, Australia, Eurasia and North America. As ginglymodians, their closest living relatives are gars, with them being typically placed as nested within the Semionotiformes. Many members of the family have elongated dorsal fins, often associated with adjacent area of skin which was free of scales. These fins were likely undulated for use in precision swimming. Their body morphology suggests that they were slow swimmers that were capable of maneuvering around complex topography, such as reef environments.

<span class="mw-page-title-main">Phu Kradung Formation</span> Geologic formation in Thailand

The Early Cretaceous Phu Kradung Formation is the lowest member of the Mesozoic Khorat Group which outcrops on the Khorat Plateau in Isan, Thailand. This geological formation consists of micaceous, brown to reddish-brown siltstone beds with minor brown and grey shale and sandstone beds. Occasional lime-noduled conglomerate occurs.

<i>Scheenstia</i> Extinct genus of fishes

Scheenstia is an extinct genus of neopterygian ray-finned fish from the Late Jurassic–Early Cretaceous of Europe. Fossils have been found in both marine and freshwater environments.

<i>Callipurbeckia</i> Extinct genus of fishes

Callipurbeckia is an extinct genus of neopterygian ray-finned fish from the Jurassic and Cretaceous periods. Fossils have been found in Germany, Tanzania, and England. It contains three species, which were previously classified in the related genus Lepidotes.

<span class="mw-page-title-main">Halecomorphi</span> Clade of fishes

Halecomorphi is a taxon of ray-finned bony fish in the clade Neopterygii. The only extant Halecomorph species are the bowfin and eyespot bowfin, but the group contains many extinct species in several families in the order Amiiformes, as well as the extinct orders Ionoscopiformes, Panxianichthyiformes, and Parasemionotiformes. The fossil record of halecomorphs goes back at least to the Early Triassic epoch.

<i>Amia</i> (fish) Genus of ray-finned fishes

Amia, commonly called bowfin, is a genus of bony fish related to gars in the infraclass Holostei. They are regarded as taxonomic relicts, being the sole surviving species of the order Amiiformes, which dates from the Jurassic to the Eocene, persisting to the present. There are two living species in Amia, Amia calva and Amia ocellicauda, and a number of extinct species which have been described from the fossil record.

<span class="mw-page-title-main">Sinamiidae</span> Extinct family of fishes

Sinamiidae is an extinct family of ray-finned fish. They are halecomorph fishes endemic to Early Cretaceous freshwater environments in East and Southeast Asia.

<span class="mw-page-title-main">Ginglymodi</span> Clade of ray-finned fishes

Ginglymodi is a clade of ray-finned fish containing modern-day gars (Lepisosteidae) & their extinct relatives in the order Lepisosteiformes, the extinct orders Semionotiformes and Kyphosichthyiformes, and various other extinct taxa. Ginglymodi is one of the two major subgroups of the infraclass Holostei, the other one being Halecomorphi, which contains the bowfin and eyespot bowfin and their fossil relatives.

<span class="mw-page-title-main">Dapediidae</span> Extinct family of ray-finned fishes

Dapediidae is an extinct family of neopterygian ray-finned fish that lived from the Late Triassic to Late Jurassic. It is the only family of the order Dapediiformes. Its members were historically placed within the ginglymodian family Semionotidae, but were moved to their own family in 1966.

<span class="mw-page-title-main">Parasemionotiformes</span> Extinct order of ray-finned fishes

Parasemionotiformes is an extinct order of neopterygian ray-finned fish that existed globally during the Triassic period. It comprises the families Parasemionotidae and Promecosominidae. Many of the included genera are monotypic and most species lived during the Early Triassic epoch.

<span class="mw-page-title-main">Lepidotidae</span> Extinct family of fish

Lepidotidae is an extinct family of fish, known from the Jurassic and Cretaceous periods. Most species were originally assigned to the genus Lepidotes which was long considered a wastebasket taxon. Cladistic analysis has indicated that they are close relatives of gars, with both being members of the order Lepisosteiformes. Members of the family are known from both marine and freshwater environments. Their bulky body morphology and small median fins suggests that they were slow-moving fish that were capable of performing fine movements in order to grasp prey. Lepidotes sensu stricto had peg-like grasping marginal teeth and crushing palatal teeth, and is known to have consumed small crustaceans, while Scheenstia had low rounded crushing marginal teeth, indicating a durophagous diet.

<i>Araripelepidotes</i> Genus of semionotiform fish

Araripelepidotes is a genus of ginglymodian fish.

<span class="mw-page-title-main">Obaichthyidae</span> Extinct family of ray-finned fishes

Obaichthyidae is an extinct family of ginglymodian ray-finned fish that lived in what is now Africa and South America during the Cretaceous period. It was erected in 2010 by Lance Grande to include the genera Dentilepisosteus and Obaichthys. In 2012, it was defined as a stem-based taxon containing all taxa more closely related to Obaichthys than to the genera Lepisosteus, Pliodetes or Lepidotes.

Oniichthys is an extinct genus of gar in the family Lepisosteidae. It contains a single species, O. falipoui, known from the Late Cretaceous (Cenomanian) of Morocco.

References

  1. 1 2 3 4 5 López-Arbarello, A. (2012). "Phylogenetic Interrelationships of Ginglymodian Fishes (Actinopterygii: Neopterygii)". PLOS ONE. 7 (7): e39370. Bibcode:2012PLoSO...739370L. doi: 10.1371/journal.pone.0039370 . PMC   3394768 . PMID   22808031.
  2. "Order Summary for Lepisosteiformes". fishbase.mnhn.fr. Retrieved 2023-11-25.
  3. López-Arbarello, Adriana (2012-07-11). "Phylogenetic Interrelationships of Ginglymodian Fishes (Actinopterygii: Neopterygii)". PLOS ONE. 7 (7): e39370. Bibcode:2012PLoSO...739370L. doi: 10.1371/journal.pone.0039370 . ISSN   1932-6203. PMC   3394768 . PMID   22808031.
  4. Grande, Lance (2010). "An empirical synthetic pattern study of gars (Lepisosteiformes) and closely related species, based mostly on skeletal anatomy. The resurrection of Holostei". Copeia. 10 (2A): 1–871. Retrieved 2023-11-25.
  5. 1 2 3 Deesri, U.; Jintasakul, P.; Cavin, L. (2016). "A new Ginglymodi (Actinopterygii, Holostei) from the Late Jurassic–Early Cretaceous of Thailand, with comments on the early diversification of Lepisosteiformes in Southeast Asia". Journal of Vertebrate Paleontology. 36 (6): e1225747. Bibcode:2016JVPal..36E5747D. doi:10.1080/02724634.2016.1225747. S2CID   89359438.
  6. 1 2 Cavin, Lionel; Deesri, Uthumporn; Olive, Sébastien (2019-07-22). "Scheenstia bernissartensis (Actinopterygii: Ginglymodi) from the Early Cretaceous of Bernissart, Belgium, with an appraisal of ginglymodian evolutionary history". Journal of Systematic Palaeontology. 18 (6): 513–527. doi:10.1080/14772019.2019.1634649. ISSN   1477-2019. S2CID   199631685.
  7. Cawley, John J.; Marramà, Giuseppe; Carnevale, Giorgio; Villafaña, Jaime A.; López‐Romero, Faviel A.; Kriwet, Jürgen (February 2021). "Rise and fall of †Pycnodontiformes: Diversity, competition and extinction of a successful fish clade". Ecology and Evolution. 11 (4): 1769–1796. doi:10.1002/ece3.7168. ISSN   2045-7758. PMC   7882952 . PMID   33614003.
  8. de Paiva, H. C. L.; Gallo, V. (2018). "Quasimodichthys gen. nov. (Neopterygii: Semionotiformes): A morphological and ontogenetic study". Journal of South American Earth Sciences. 88: 132–143. Bibcode:2018JSAES..88..132P. doi:10.1016/j.jsames.2018.08.010. S2CID   134986658.
  9. Murray, A. M.; Xing, L.; Divay, J.; Liu, J.; Wang, F. (2015). "A Late Jurassic freshwater fish (Ginglymodi, Lepisosteiformes) from Qijiang, Chongqing, China". Journal of Vertebrate Paleontology. 35 (2): e911187. Bibcode:2015JVPal..35E1187M. doi:10.1080/02724634.2014.911187. S2CID   85946657.