Ginglymodi

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Ginglymodi
Temporal range: Middle Triassic (Anisian)–present
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Possible Permian records
Kaimanfisch (Lepisosteus oculatus).jpg
Spotted gar (Lepisosteus oculatus)
Macrosemimimus fegerti.jpg
Macrosemimimus fegerti (Semionotiformes) from the Upper Jurassic of Germany
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Infraclass: Holostei
Clade: Ginglymodi
Cope, 1871
Subgroups

Ginglymodi is a clade of ray-finned fish containing modern-day gars (Lepisosteidae) and their extinct relatives (including the family Lepidotidae) 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. [1] [2]

Contents

Fossil record

The fossil record of ginglymodians goes back at least to the Anisian stage of the Triassic period, over 240 million years ago. [3] Eosemionotus is one of the earliest ginglymodians. Acentrophorus , another taxon from the Middle and Late Permian, and Paracentrophorus from the Early Triassic epoch, could be even earlier members of the group. Ginglymodi was diverse and widespread during the Mesozoic era, but they represent a depauperate lineage today. The group first evolved in marine environments, but several lineages made separate transitions into freshwater environments. [4] The basal ginglymodian order Kyphosichthyiformes is known from a few genera from the Triassic of China, many of which have deep bodies. [5]

Ginglymodi underwent substantial diversification during the Late Triassic and the Late Jurassic, with the Lepisosteiformes and Semionotiformes having likely diverged during the Middle Triassic. [6] Early non-gar ginglymodians of all groups, but especially early lepisosteiforms, show heavy morphological convergence with modern cypriniforms (carp and relatives), suggesting that they may have had a similar ecological niche. Notably, molecular evidence suggests that the cypriniforms may have originated and diversified around the same time and place (Late Jurassic and Early Cretaceous Southeast Asia) that the similar freshwater ginglymodians showed major diversification. [7] Eventually, some ginglymodians evolved a more predatory lifestyle, with the earliest known true gars from the Late Jurassic. [8] Ginglymodians underwent a major decline during the mid-Cretaceous, eventually leaving gars as the only surviving members of the group. [6] Gar fossils have been found on all continents except Australia and Antarctica. Only seven species exist today, distributed in the freshwater systems of North America. [8]

Phylogeny

Phylogenetic relationships of Ginglymodi to other living neopterygian fish.

Neopterygii

Teleostei Common carp (white background).jpg

Holostei

Halecomorphi (bowfin, eyespot bowfin and their fossil relatives) Amia calva (white background).jpg

Ginglymodi (gars and their fossil relatives) Alligator gar fish (white background).jpg

Phylogenetic relationships among different groups of ginglymodians (cladogram after Xu & Ma 2023): [9]

Ginglymodi

Related Research Articles

<span class="mw-page-title-main">Actinopterygii</span> Class of ray-finned bony fishes

Actinopterygii, members of which are known as ray-finned fish or actinopterygians, is a class of bony fish that comprise over 50% of living vertebrate species. They are so called because of their lightly built fins made of webbings of skin supported by radially extended thin bony spines called lepidotrichia, as opposed to the bulkier, fleshy lobed fins of the sister class Sarcopterygii. Resembling folding fans, the actinopterygian fins can easily change shape and wetted area, providing superior thrust-to-weight ratios per movement compared to sarcopterygian and chondrichthyian fins. The fin rays attach directly to the proximal or basal skeletal elements, the radials, which represent the articulation between these fins and the internal skeleton.

<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, had 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 who 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.

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

Lepisosteiformes is an order of ray-finned fish and the only living members of the clade Ginglymodi. Its only extant representatives are the gar, 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.

<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, which are putative "semionotiforms" such as Acentrophorus and Archaeolepidotus, are known from the Middle to Late Permian and are among the earliest known neopterygians.

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

Halecostomi is the name of a group of neopterygian fish uniting the halecomorphs and the teleosts, the largest group of extant ray-finned fish.

<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.

The Khok Kruat Formation is a rock formation found in northeastern Thailand. It is the uppermost formation of the Khorat Group. It is dated to the Aptian stage of the Early Cretaceous period, and is notable for its fossils of dinosaurs. It is equivalent to the Gres superieurs Formation of Laos. The group is a fluvial formation consisting primarily of red siltstones and sandstones.

<i>Kyphosichthys</i> Extinct genus of ray-finned fishes

Kyphosichthys is an extinct genus of basal actinopterygian bony fish known from the lower Middle Triassic (Anisian) marine deposits in Luoping, eastern Yunnan Province, southwestern China. The species is the first known fossil record of highly deep-bodied ginglymodians.

<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 marine semionotiform ray-finned fish from the Late Jurassic and Early Cretaceous periods. Fossils have been found in Germany, Tanzania, and England.

<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.

<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">Dapediidae</span> Extinct family of ray-finned fishes

Dapediidae is an extinct family of neopterygian ray-finned fish that lived from the Middle 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">Redfieldiiformes</span> Extinct order of ray-finned fishes

Redfieldiiformes is an extinct order of ray-finned fish (actinopterygians) which lived from the Early Triassic to Early Jurassic. Redfieldiiforms were fairly typical Triassic fish in overall anatomy. They had a fusiform body shape with thick, ganoine-covered scales. The dorsal and anal fins were large, positioned opposite from each other, and shifted back, close to the tail. The caudal fin was hemiheterocercal, with the vertebral column and body scales extending into an upper lobe equal in size and shape to the lower lobe. They also had several characteristic skeletal traits, such as a hatchet-shaped preopercle, a series of fulcra fringing the fins, a reduced number of branchiostegal rays, and a snout ornamented with tubercles.

<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.

<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. Afrocascudo, initially described as the earliest known armored catfish, might represent a juvenile obaichthyid, possibly a junior synonym of Obaichthys, though this has been disputed based on the complete ossification of the bones indicating full maturity and the absence of important holostean characters.

References

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  2. Nelson, Joseph S. (2016). Fishes of the World. John Wiley & Sons, Inc. ISBN   978-1-118-34233-6.
  3. Romano, Carlo (2021). "A Hiatus Obscures the Early Evolution of Modern Lineages of Bony Fishes". Frontiers in Earth Science. 8: 672. doi: 10.3389/feart.2020.618853 . ISSN   2296-6463.
  4. 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.
  5. Xu, G.; Ma, X.; Wu, F.; Ren, Y. (2019). "A Middle Triassic kyphosichthyiform from Yunnan, China, and phylogenetic reassessment of early ginglymodians". Vertebrata PalAsiatica. 57 (3): 181–204. doi:10.19615/j.cnki.1000-3118.190319.
  6. 1 2 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.
  7. Deesri, Uthumporn; Jintasakul, Pratueng; Cavin, Lionel (2016-10-07). "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. doi:10.1080/02724634.2016.1225747. ISSN   0272-4634. S2CID   89359438.
  8. 1 2 Paulo M. Brito; Jésus Alvarado-Ortega; François J. Meunier (2017). "Earliest known lepisosteoid extends the range of anatomically modern gars to the Late Jurassic". Scientific Reports. 7 (1): Article number 17830. Bibcode:2017NatSR...717830B. doi:10.1038/s41598-017-17984-w. PMC   5736718 . PMID   29259200.
  9. Xu, Guang-Hui; Ma, Xin-Ying (2023-10-16). "A new basal ginglymodian fish (Holostei: Neopterygii) from the Middle Triassic (Anisian) Luoping Biota, Yunnan, China". Zoological Journal of the Linnean Society. doi:10.1093/zoolinnean/zlad144. ISSN   0024-4082.