Tristichopteridae

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Tristichopteridae
Temporal range: 392–359  Ma
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Middle - Late Devonian
Platycephalichthys teeth detail.jpg
Teeth of Platycephalichthys , in CosmoCaixa Barcelona
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Clade: Sarcopterygii
Clade: Tetrapodomorpha
Clade: Eotetrapodiformes
Family:† Tristichopteridae
Cope, 1889
Genera
Synonyms
  • Eusthenopteridae Berg, 1955

Tristichopterids (Tristichopteridae) were a diverse and successful group of fish-like tetrapodomorphs living throughout the Middle and Late Devonian. They first appeared in the Eifelian stage of the Middle Devonian. Within the group sizes ranged from a few tens of centimeters ( Tristichopterus ) to several meters ( Hyneria and Eusthenodon ).

Contents

Some tristichopterids share some of the features of the elpistostegalians, a diverse clade of tetrapodomorphs close to the origin of (and including) tetrapods. [1] [ better source needed ] This mainly concerns the shape of the skull and a reduction in size of the posterior fins.

An old and persistent notion is that Eusthenopteron was able to crawl onto land using its fins. However, there is no evidence actually supporting this idea. [2] All tristichopterids had become extinct by the end of the Late Devonian.

Description

The Tristichopteridae were medium-sized (Tristichopterus, 30 cm) to very large animals. The smallest forms (such as Tristichopterus) attained lengths of 30 cm, and the largest forms (Hyneria) could grow several meters long, possessed teeth up to 5 cm long, and were the largest predators in their faunal communities. [3] Tristichopterids had a strongly developed fin skeleton. In the skeleton of the front fins, which were deeply attached, the elements of the forelimb of the later tetrapodomorphs, such as the humerus, ulna and radius, can already be recognized.

Comparisons of the skulls of three members of the Tristichopteridae: A, B, C, Edenopteron; D, Eusthenodon, E. Cabonnichthys; F, Mandageria. Skull and shoulder-girdle restorations of Tristichopterids.jpg
Comparisons of the skulls of three members of the Tristichopteridae: A, B, C, Edenopteron ; D, Eusthenodon , E. Cabonnichthys ; F, Mandageria .

The parts of the bones directed outward from the body trunk were flattened. The pelvis had long, tapering pubic branches (pubic rami) that possibly met in a cartilaginous symphysis. The ventral fins also contained the major bones of the hind legs, femur, tibia, and fibula. Ankle bones (tarsal bones) and toes cannot yet be identified. The limbs were oriented to the side and could only be moved back and forth about 20 to 25°. The anal fin sat on a basal, fleshy peduncle. The caudal fin possessed three lobes, initially asymmetrical in basal forms and becoming more symmetrical externally in later forms. The scales lacked the cosmine layer found in more primitive tetrapodomorphs. Most of the body was covered in round, overlapping elasmoid scales with a median projection on the inner side. Thicker, enlarged scales occurred on the bases of the fins. [4] The earliest-known fossilised evidence of bone marrow has been found in Eusthenopteron, which may be the origin of bone marrow in tetrapods. [5]

The ontogeny of the Tristichopteridae is relatively well-known, and can be somewhat reliably inferred through Eusthenopteron. [6] Eusthenopteron differs significantly from some later Carboniferous tetrapods in the apparent absence of a recognized larval stage and a definitive metamorphosis. In even the smallest known specimen of Eusthenopteron foordi (at 29 mm), the lepidotrichia cover all of the fins, which does not happen until after metamorphosis in genera like Polyodon . This might indicate that Eusthenopteron developed directly, with the hatchling already attaining the general body form of the adult. [7]

Taxonomy

The family Tristichopteridae was named by Edward Drinker Cope in 1889, who established it as the sole family of the order Rhipidistia. In turn, Cope deemed Rhipidistia and Actinistia as the two orders forming a superorder he named Rhipidopterygia. [8] In 1955, Lev Berg erected a family named Eusthenopteridae to include the genera Tristichopterus and Eusthenopteron, and placed this family within the order Rhizodontiformes. [9] More genera would later be placed in Eusthenopteridae, with Vorobyeva and Obruchev (1964) stating Eusthenodon and possibly Platycephalichthys are members of this family, while Carroll (1988) added Hyneria and tentatively assigned Devonosteus and Litoptychus to the group. [10] [11] Currently, Eusthenopteridae is deemed a junior synonym of Tristichopteridae. [12]

In the past, Tristichopteridae was assigned to the order Osteolepiformes, a group of tetrapodomorphs that is now considered paraphyletic.

The following phylogeny is modified from Schwartz (2012). Here, Platycephalichthys is not considered a member of the Tristichopteridae: [1]

Tristichopteridae

Related Research Articles

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

Sarcopterygii — sometimes considered synonymous with Crossopterygii — is a clade of bony fish commonly referred to as lobe-finned fish. They are characterised by prominent muscular limb buds (lobes) within their 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 supporting the fins.

<span class="mw-page-title-main">Erik Jarvik</span> Swedish paleontologist

Anders Erik Vilhelm Jarvik was a Swedish paleontologist who worked extensively on the sarcopterygian fish Eusthenopteron. In a career that spanned some 60 years, Jarvik produced some of the most detailed anatomical work on this fish, making it arguably the best known fossil vertebrate.

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

Eusthenopteron is a genus of prehistoric sarcopterygian fishes known from several species that lived during the Late Devonian period, about 385 million years ago. It has attained an iconic status from its close relationship to tetrapods. Early depictions of animals of this genus show them emerging onto land, but paleontologists now widely agree that eusthenopteron species were strictly aquatic animals.

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

Panderichthys is a genus of extinct sarcopterygian from the late Devonian period, about 380 Mya. Panderichthys, which was recovered from Frasnian deposits in Latvia, is represented by two species. P. stolbovi is known only from some snout fragments and an incomplete lower jaw. P. rhombolepis is known from several more complete specimens. Although it probably belongs to a sister group of the earliest tetrapods, Panderichthys exhibits a range of features transitional between tristichopterid lobe-fin fishes and early tetrapods. It is named after the German-Baltic paleontologist Christian Heinrich Pander. Possible tetrapod tracks dating back to before the appearance of Panderichthys in the fossil record were reported in 2010, which suggests that Panderichthys is not a direct ancestor of tetrapods, but nonetheless shows the traits that evolved during the fish-tetrapod evolution

<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.

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

Tetrapodomorpha is a clade of vertebrates consisting of tetrapods and their closest sarcopterygian relatives that are more closely related to living tetrapods than to living lungfish. Advanced forms transitional between fish and the early labyrinthodonts, such as Tiktaalik, have been referred to as "fishapods" by their discoverers, being half-fish, half-tetrapods, in appearance and limb morphology. The Tetrapodomorpha contains the crown group tetrapods and several groups of early stem tetrapods, which includes several groups of related lobe-finned fishes, collectively known as the osteolepiforms. The Tetrapodomorpha minus the crown group Tetrapoda are the stem Tetrapoda, a paraphyletic unit encompassing the fish to tetrapod transition.

<span class="mw-page-title-main">Rhizodontida</span> Extinct order of tetrapodomorphs

Rhizodontida is an extinct group of predatory tetrapodomorphs known from many areas of the world from the Givetian through to the Pennsylvanian - the earliest known species is about 377 million years ago (Mya), the latest around 310 Mya. Rhizodonts lived in tropical rivers and freshwater lakes and were the dominant predators of their age. They reached huge sizes - the largest known species, Rhizodus hibberti from Europe and North America, was an estimated 7 m in length, making it the largest freshwater fish known.

<span class="mw-page-title-main">Fram Formation</span> Geologic formation in Nunavut, Canada

The Fram Formation is an Upper Devonian (Frasnian) sequence of rock strata on Ellesmere Island that came into prominence in 2006 with the discovery in its rocks of examples of the transitional fossil, Tiktaalik, a sarcopterygian or lobe-finned fish showing many tetrapod characteristics. Fossils of Laccognathus embryi, a porolepiform lobe-finned fish, and Qikiqtania, a close relative of Tiktaalik, were also found in the formation. The Fram Formation is a Middle to Upper Devonian clastic wedge forming an extensive continental facies consisting of sediments derived from deposits laid down in braided stream systems that formed some 375 million years ago, at a time when the North American craton ("Laurentia") was straddling the equator.

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

Mandageria fairfaxi is an extinct lobe-finned fish that lived during the Late Devonian period. It is related to the much larger Hyneria; although Mandageria was smaller, it probably hunted in the same way.

<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>Tristichopterus</i>

Tristichopterus, with a maximum length of sixty centimetres, is the smallest genus in the family of prehistoric lobe-finned fish, Tristichopteridae that was believed to have originated in the north and dispersed throughout the course of the Upper Devonian into Gondwana. Tristichopterus currently has only one named species, first described by Egerton in 1861. The Tristichopterus node is thought to have originated during the Givetian part of the Devonian. Tristichopterus was thought by Egerton to be unique for its time period as a fish with ossified vertebral centers, breaking the persistent notochord rule of most Devonian fish but this was later reinspected and shown to be only partial ossification by Dr. R. H. Traquair. Tristichopterus alatus closely resembles Eusthenopteron and this sparked some debate after its discovery as to whether it was a separate taxon.

<span class="mw-page-title-main">Osteolepiformes</span> Paraphyletic group of tetrapodomorphs

Osteolepiformes, also known as Osteolepidida, is a group of prehistoric lobe-finned fishes which first appeared during the Devonian period. The order contains the families Canowindridae, Megalichthyidae, Osteolepididae and Tristichopteridae. The order is generally considered to be paraphyletic because the characters that define it are mainly attributes of stem tetrapodomorphs.

<span class="mw-page-title-main">Megalichthyidae</span> Extinct family of tetrapodomorphs

Megalichthyidae is an extinct family of tetrapodomorphs which lived from the Middle–Late Devonian to the Early Permian. They are known primarily from freshwater deposits, mostly in the Northern Hemisphere, but one genus (Cladarosymblema) is known from Australia, and the possible megalichthyid Mahalalepis is from Antarctica.

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

Laccognathus is an extinct genus of amphibious lobe-finned fish from Europe and North America. They existed from the Middle Devonian to the Late Devonian. The name comes from Greek for 'pitted jaw'.

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

Marsdenichthys is an extinct genus of Devonian tetrapodomorph. Fossils have been found from Mount Howitt in Victoria, Australia from strata that are Givetian-Frasnian in age. Mount Howitt is an important site that has been the source of many tetrapodomorph fossils, including Beelarongia and Howittichthys, both of which were first described from the locality.

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

Langlieria is a genus of prehistoric sarcopterygian, from the end of the Devonian period (Famennian). It was discovered in Belgium and Pennsylvania.

<i>Tinirau clackae</i> Extinct species of tetrapodomorph

Tinirau is an extinct genus of sarcopterygian fish from the Middle Devonian of Nevada. Although it spent its entire life in the ocean, Tinirau is a stem tetrapod close to the ancestry of land-living vertebrates in the crown group Tetrapoda. Relative to more well-known stem tetrapods, Tinirau is more closely related to Tetrapoda than is Eusthenopteron, but farther from Tetrapoda than is Panderichthys. The type and only species of Tinirau is T. clackae, named in 2012.

<span class="mw-page-title-main">Eotetrapodiformes</span> Clade of tetrapodomorphs

Eotetrapodiformes is a clade of tetrapodomorphs including the four-limbed vertebrates and their closest finned relatives, two groups of stem tetrapods called tristichopterids and elpistostegalids.

The Escuminac Formation is a geologic formation in Quebec. It preserves fossils dating back to the Frasnian, in the Devonian period.

The Mandagery Sandstone is a Late Devonian geological formation in New South Wales, Australia. It is one of several famed Australian lagerstätten, with thousands of exceptional fish fossils found at a site near the town of Canowindra.

References

  1. 1 2 Swartz, B. (2012). "A marine stem-tetrapod from the Devonian of Western North America". PLOS ONE. 7 (3): e33683. Bibcode:2012PLoSO...733683S. doi: 10.1371/journal.pone.0033683 . PMC   3308997 . PMID   22448265.
  2. ↑ M. Laurin, F. J. Meunier, D. Germain, and M. Lemoine 2007. A microanatomical and histological study of the paired fin skeleton of the Devonian sarcopterygian Eusthenopteron foordi. Journal of Paleontology 81: 143–153.
  3. ↑ Thomson, K. S. (1968). "A new Devonian fish (Crossopterygii: Rhipidistia) considered in relation to the origin of the Amphibia". Postilla. 124.
  4. ↑ Zylberberg, L., Meunier, F. J. and Laurin, M. 2010. A microanatomical and histological study of the postcranial dermal skeleton in the Devonian sarcopterygian Eusthenopteron foordi. Acta Palaeontologica Polonica 55: 459–470.
  5. ↑ Sanchez S, Tafforeau P and Ahlberg P E (2014) "The humerus of Eusthenopteron: a puzzling organization presaging the establishment of tetrapod limb bone marrow" Proceedings of the Royal Society B: Biological Sciences, 281 (1782): 20140299. doi:10.1098/rspb.2014.0299
  6. ↑ Schultze, H.-P. 1984. Juvenile specimens of Eusthenopteron foordi Whiteaves, 1881 (Osteolepiform rhipidistian, Pisces) from the Late Devonian of Miguasha, Quebec, Canada. Journal of Vertebrate Paleontology 4: 1-16.
  7. ↑ S. Cote; R. Carroll; R. Cloutier; L. Bar-Sagi (September 2002). "Vertebral development in the Devonian Sarcopterygian fish Eusthenopteron foordi and the polarity of vertebral evolution in non-amniote tetrapods". Journal of Vertebrate Paleontology. 22 (3): 487–502. doi:10.1671/0272-4634(2002)022[0487:VDITDS]2.0.CO;2. ISSN 0272-4634.
  8. ↑ Cope, E. D. (1889). "Synopsis of the Families of Vertebrata". The American Naturalist. 23 (274): 849–877. ISSN   0003-0147.
  9. ↑ Berg, L.S. (1955). "Classification of fish-like vertebrates, living and fossil. 2., corrected and enlarg". Trudy Zoologicheskogo instituta (in Russian). 20: 1–286.
  10. ↑ Vorobyeva, E.I.; Obruchev, D.V. (1964). Osnovy Paleontologii[Fundamentals of Paleontology] (in Russian). Vol. XI. Agnatha, Pisces. Moscow. pp. 268–322.{{cite book}}: CS1 maint: location missing publisher (link)
  11. ↑ Carroll, Robert Lynn (1988). Vertebrate paleontology and evolution. New York, N.Y: Freeman. ISBN   978-0-7167-1822-2.
  12. ↑ Schultze, Hans-Peter; Cloutier, Richard (1996). "Taxonomic review of Eusthenopteron foordi". Devonian Fishes and Plants of Miguasha, Quebec, Canada. F. Pfeil. pp. 271–284. ISBN   978-3-931516-03-1.
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