Ishnakantobraznye [1] ( lat. Ischnacanthiformes ) - a squad of extinct fish from the class of acanthodes (Acanthodii). Representatives of the detachment appeared in Silurian ( ) and became extinct in the Upper Devonian [2] [3] . In the Devonian, they were distributed almost everywhere (their fossil remains were found on all continents except Africa) [4] .
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 Reconstruction of Ishnacanthus gracilis | |||||||||||||||||||||||||||||||||||||||||
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Ischnacanthiformes Berg , 1940 | |||||||||||||||||||||||||||||||||||||||||
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| Geochronology 430-370 Ma
◄ Nowadays◄ Cretaceous-Paleogene extinction◄ Triassic extinction◄ Perm mass extinction◄ Devonian extinction◄ Ordovician-Silurian extinction◄ Cambrian explosion | |||||||||||||||||||||||||||||||||||||||||
The order is named for the genus Ischnacanthus. First distinguished in 1940 by L. S. Berg; later, the detachment was expanded to include newly opened labor . The evolutionary history of the ishnakantobraznyh covers the second half of the Silurian and Devonian . The detachment includes both poorly specialized forms of food and actively swimming predators; the ishnakantobraznye differed from other squads of the class primarily by the presence of teeth attached to the dermal bones, as well as by the features of the cover . The detachment includes two or three families . Data on its systematic position within the acantode class remain controversial .
Unit Name
The name of the order is derived from the name of its type genus Ischnacanthus by adding to the base the name of the genus standard for the names of fish orders ending -iformes [5] . In turn, the genus Ischnacanthus was first identified in the article “On the fossiliferous rocks of Forfarshire and their contents” by Scottish natural scientist James Pauri in 1864 (Pauri singled out the species of acanthodes, first described in 1859 by under titled Diplacanthus gracilis [6] ). The name of the genus was formed from other Greek. phrases ἰσχνός ἄκανθος 'thin spine' and given in connection with the shape of ichthiodorulites (fin spikes) characteristic of its representatives - long, relatively thin and slightly curved, with a rounded cross section [7] [8] .
Study History
The history of the study of the detachment dates back to 1837, when the Swiss natural scientist Louis Agassis described the genus Onchus ; this genus was known only by the findings of individual fin spikes, and the scientist in his treatise Recherches sur les poissons fossiles (1833-1843, 5 volumes) included him in the Ichthyodorulites team [9] . In 1839, he described - also from the findings of individual fin spines - the genus Plectrodus [10] . At present, these two genera are either assigned to the order of Ishnakantiformes or are considered as acanthodes of an unclear systematic position [11] [12] .
In the second half of the 19th century, H. I. Pander , J. Newberry , F. Egerton, J. Pauri, and other paleontologists made their contribution to the study of ishnakantobraznyh; they described several more genera ( Gomphodus Pander, 1856 , Monopleurodus Pander, 1856 , Machaeracanthus Newberry, 1860 , Ischnacanthus Powrie, 1864 , Doliodus Traquair, 1893 ), which are now assigned to this order [11] . In 1891, the English paleontologist Arthur Woodward singled out the Ischnacanthidae family in the order Acanthodii (then the taxon of the Acanthode was of this rank ) and included only one genus Ischnacanthus in it (at that time only well-preserved fossils were found for it) [13] . Woodward still assigned the Onchus and Machaeracanthus genera to the Ichthyodorulites group [14] , and he generally considered the genus Gomphodus and Plectrodus to be jawed [15] .
In 1940, the Soviet ichthyologist L. S. Berg in the first edition of his work, “The system of fish-shaped and fish that are now living and fossil” [16] singled out acanthodes into a separate class of fish and divided it into seven orders, including the Ischnacanthiformes order with one family of Ischnacanthidae . Such a fractional division of the acantode class by other paleontologists was considered, however, excessive [17] . For a long time, only three orders were recognized in the class — Acanthodiformes , Climatiiformes, and Ischnacanthiformes [12] [18] ; at the turn of the 20th — 21st centuries, the Diplacanthiformes detachment (already existing in the Berg system) was added to them [19] [20] .
During the XX and beginning of the XXI century, the study of ishnakantobraznyh continued. New genera have been described: Marsdenius Wellburn, 1902 , Atopacanthus Hussakof & Bryant, 1919 , Byssacanthoides Woodward, 1921 , Poracanthodes Brotzen, 1934 , Xylacanthus Ørvig, 1967 , Gomphonchus Gross, 1971 , Persacanthus Janvier, 1977 , Rockasamp , 1986ycas 1986 , Trundlelepis Burrow, 1997 ; Zemlyacanthus Vergoossen, 1997 ; Gomphonchoporus Vergoossen; 1999 ; Radioporacanthodes Vergoossen; 1999 ; Arcticacanthus Valiukevičius; 2003 ; Arenaceacanthus Valiukevičius ; Hermus & Wilson, 2015 , Euryacanthus Blais, Hermus & Wilson, 2015 , Tricuspiacanthus Blais, Hermus & Wilson, 2015 and others. In 1997, a new family of Poracanthodidae [3] [11] [18] [21] [ 22] [23] .
Evolutionary History
The earliest finds of the Ishnakantiformes belong to the middle of the Silurian (Wenlock, 430 Ma): it is in the Venlok deposits that the earliest fossil remains ( scales ) of the species Arenaceacanthus arcuatacanalis , the earliest of the species belonging to this order, were found [3] . However, almost all species known from Silurian (belonging to the genera Bracteatacanthus , Gomphonchus , Poracanthodes , Rohonilepis , Xylacanthus , etc. [3] [18] ) are described by residues represented only by isolated elements - including scales, fin spikes, tooth spirals, integumentary jaw bones. Skeletal remains are currently known only for two species of ishnakantoids from : Onchus graptolitarum ( Czech Republic ; incomplete skeleton) and Nerepisacanthus denisoni (Canada; almost complete skeleton) [24] . The oldest known ishnakantoobraznyh for which the structure of the jaw bones is known, is a specimen of Xylacanthus described in 2001 from deposits of northern Canada , presumably related to the early [18] .
Acritolepis , Erymnacanthus , Euryacanthus , Helenacanthus , , Rockycampacanthus , Taemasacanthus , Tricuspiacanthus , Zemlyacanthus , and Atopacanthus , Byssacanthoides , [24] 18 [23] are known from the Lower Devonian, [23 ] . At the end of the Devonian (370 million years ago), the ishnakantoobraznye die out [25] [26] . Perhaps the extinction was incomplete, and the history of the ishnakantoobraznyh will be extended into the Lower Carboniferous , if it is possible to confirm belonging to the order of the genus Marsdenius (found from fossil remains found in 1902 in Yorkshire's early Carboniferous deposits of fish with teeth fixed on dermal bones, two dorsal fins and ornamented side scales); however, from the moment of description, the remains were lost [18] .
Description
Ishnakantoobraznye - fish of medium and large (up to 2 m in length) sizes with a spindle-shaped body and head covered with scales or small plates (often such a cover was limited only to the area of the cheeks). Their jaws were covered with bones of dermal origin, attached to the border of Meckel’s and cartilage (the latter were ossified by two bones each [27] ). These dermal bones carried large teeth (some species also had additional rows of small teeth in the oral cavity) [4] [28] .
Like other acanthodes, the representatives of the order had spikes in front of each fin (except for the tail ); at the same time, in the pectoral fin belt of the ishnakantoids there were no bone plates, and additional spines between the pectoral and ventral fins were also usually absent. There are two dorsal fins . The skeleton of the fins was deeply immersed in the thickness of the body of the fish. The scales are characterized by a mixed type of structure: their base was formed by cellular bone tissue, and the crown was from dentin with a thin enamel-like outer layer; at the same time, the scales were thinner than that of climate-friendly ones. The scales located near the channels of the lateral line had porous tubules (which is also characteristic of some bone fish ) [4] [29] [28] .
The ishnakantoids differ from all other acanthode orders by the presence of well-developed teeth attached to the dermal bones (such bones, however, were present in the Acanthodopsis genus belonging to the acanthoides, but they were not homologous to the ishnakanto dermal bones, and there were no real teeth from representatives of this genus [18] ); from the early forms of climate-like and acanthode-like - also by the presence of only the main gill cover , completely covering the [30] .
They lived mainly in the sea. The earliest representatives of the order were poorly specialized in the nature of their feeding; later, they were actively swimming nekton predators [18] [25] .
Systematic position
Currently, there is no generally accepted point of view on the systematic position of the ishnakantoobraznyh. For example, in a 2012 study by Davis, Finarelli, and Coates, the acantode class is a paraphyletic group that lies at the base of the Eugnathostomata group (a clade that includes all the maxillary minus placoderms [31] ), while the ishnacanthidae turn out to be the sister group for the clade formed by bony fish and four-legged from them. Moreover, the phylogenetic relationships between the units of acanthodes and other Eugnathostomata groups are represented by the following cladogram [32] :
| Eugnathostomata |
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According to Zhu Ming et al. 2013, acanthodes are still paraphyletic, but are entirely part of the steem group of the cartilaginous fish class. At the same time, ishnakantoobraznye form a climate with climate-like , acanthode and cartilaginous fish, which the authors of the study failed to solve [33] :
| Eugnathostomata |
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According to a study by Barrow et al. 2016, acanthodes also belong to the steem group of the cartilaginous fish class. However, this time the families usually included in the order Climatiiformes (namely, Brochoadmonidae, Climatiidae, Euthacanthidae, Gyracanthidae [20] ) do not form a single group; the ishnakantobraznye together with the genus usually (usually referred to as Diplacanthiformes) turn out to be the sister group for Diplacanthiformes [34] :
| Eugnathostomata |
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The above cladograms do not show individual genera of acanthodes, whose membership in certain units could not be confirmed.
Classification
The composition of the ishnakantobraznyh group currently includes two extinct families [4] :
- Ischnacanthidae Woodward, 1891 (includes the genera Atopacanthus , Erymnacanthus , Euryacanthus , , Marsdenius , Tricuspicanthus , Xylacanthus, and others [4] ; the Silurian genera Arenaceacanthus , Bracteataconchus , Roct. , 35, are also included in this family);
- Poracanthodidae Vergoossen, 1997 (with the only genus Poracanthodes [4] ; sometimes the genera Gomphonchoporus , Radioporacanthodes , Trundlelepis , Zemlyacanthus [36] are also included in this family).
Apparently, the Acritolepidae Valiukevičius & Burrow, 2005 family (genera Acritolepis , Monospina , Pechoralepis , Nerepisacanthus , etc. [24] [37] ) also belongs to this order. Initially, this family was classified as climate-friendly, but later it turned out that its representatives have well-developed teeth attached to the dermal bones, which is typical for ishnakantochnyh; representatives of this family differ from other genera of the order by the presence of two pairs of pectoral thorax and the histological features of the skin [18] [37] .
Notes
- ↑ Nelson D.S. Fishes of World Fauna / Transl. 4th rev. English ed. N. G. Bogutskaya, scientific. Ed. by A. M. Nasek, A. S. Gerd. - M .: LIBROCOM Book House, 2009. - S. 151. - ISBN 978-5-397-00675-0 .
- ↑ Cherepanov, Ivanov, 2007 , p. 119, 122.
- ↑ 1 2 3 4 Valiukevičius J. New Wenlock – Pridoli (Silurian) acanthodian fishes from Lithuania // Acta Palaeontologica Polonica , 2004, 49 (1). - P. 147-160.
- ↑ 1 2 3 4 5 6 Nelson, Grande, Wilson, 2016 , p. 100.
- ↑ Berg, 1955 , p. 16, 54.
- ↑ Woodward, 1891 , p. 20-21.
- ↑ Powrie J. On the fossiliferous rocks of Forfarshire and their contents // Quarterly Journal of the Geological Society of London , 1864, 20 . - P. 413-429. - DOI : 10.1144 / GSL.JGS.1864.020.01-02.51 .
- ↑ Acanthodii . // Website Ichthyolites of the Old Red Sandstone . Date of treatment February 24, 2017.
- ↑ Agassiz, tome III, 1833-1843 , p. 6-9.
- ↑ Agassiz L. Fishes of the Upper Ludlow Rock // The Silurian System / Ed. by R. I. Murchison . - London: John Murray, 1839 .-- xxxii + 768 p. - P. 605-607.
- ↑ 1 2 3 Novitskaya, Obruchev, 1964 , p. 187-188.
- ↑ 1 2 3 Carroll R. Paleontology and the evolution of vertebrates: In 3 vols. T. 3. - M .: Mir , 1993 .-- 312 p. - ISBN 5-03-001819-0 . - S. 177-178.
- ↑ Woodward, 1891 , p. 1, 20-22.
- ↑ Woodward, 1891 , p. 94–97, 123–124.
- ↑ Woodward, 1891 , p. 159, 193.
- ↑ Berg L.S., The system of fish-like and fish, living and fossil // Tr. Zool. Institute of Academy of Sciences of the USSR. - 1940. - T. 5, no. 2 . - S. 87-517 .
- ↑ Novitskaya, Obruchev, 1964 , p. 181-182.
- ↑ 1 2 3 4 5 6 7 8 9 Burrow C. J. Acanthodian Fishes with Dentigerous Jaw Bones: the Ischnacanthiformes and Acanthodopsis // Fossils and Strata , 2004, 50 . - P. 8-22.
- ↑ Newman M. J., Burrow C. J., den Blaauwen J. L., Davidson R. G. The Early Devonian Acanthodian Uraniacanthus curtus (Powrie, 1870) n. comb. from the Midland Valley of Scotland // Geodiversitas , 2012, 34 (4). - P. 739-759. - DOI : 10.5252 / g2012n4a2 .
- ↑ 1 2 Nelson, Grande, Wilson, 2016 , p. 98-99.
- ↑ Valiukevičius J. Devonian acanthodians from Severnaya Zemlya Archipelago (Russia) // Geodiversitas , 2003, 25 (1). - P. 131-204.
- ↑ Burrow C. J., Young G. C. The acanthodian fauna of the Graven Peaks Beds (Early to Middle Devonian), western Queensland // Memoirs of the Queensland Museum , 2005, 51 (1). - P. 3-25.
- ↑ 1 2 Blais S. A., Hermus C. R., Wilson M. V. H. Four new Early Devonian ischnacanthid acanthodians from the Mackenzie Mountains, Northwest Territories, Canada: an early experiment in dental diversity // Journal of Vertebrate Paleontology , 2015, 35 (1). - Article: e948546. - DOI : 10.1080 / 02724634.2014.948546 .
- ↑ 1 2 3 Burrow C. J., Rudkin D. Oldest Near-Complete Acanthodian: The First Vertebrate from the Silurian Bertie Formation Konservat-LagerStätte, Ontario // PLoS One , 2014, 9 (8). - P. e104171. - DOI : 10.1371 / journal.pone.0104171 . .
- ↑ 1 2 Cherepanov, Ivanov, 2007 , p. 122.
- ↑ Stillwell J. D., Long J. A. Frozen in Time: Prehistoric Life in Antarctica. - Victoria: CSIRO Publishing, 2011 .-- x + 248 p. - ISBN 978-0-643-09635-6 . - P. 76.
- ↑ Novitskaya, Obruchev, 1964 , p. 189.
- ↑ 1 2 Cherepanov, Ivanov, 2007 , p. 119-123.
- ↑ Carroll R. Paleontology and evolution of vertebrates: In 3 volumes T. 1. - M .: Mir , 1992. - 280 p. - ISBN 5-03-001819-0 . - S. 111.
- ↑ Cherepanov, Ivanov, 2007 , p. 122-123.
- ↑ Nelson, Grande, Wilson, 2016 , p. 36, 40.
- ↑ Davis S. P., Finarelli J. A., Coates M. I. Acanthodes and Sharp-Like Conditions in the Last Common Ancestor of Modern Gnathostomes // Nature , 2012, 486 (7402). - P. 247-251. - DOI : 10.1038 / nature11080 .
- ↑ Zhu Min, Yu Xiaobo, Ahlberg PE, Choo B., Lu Jing, Qiao Tuo, Qu Qingming, Zhao Wenjin, Jia Liantao, Blom H., Zhu You'an. A Silurian Placoderm with Osteichthyan-Like Marginal Jaw Bones // Nature , 2013, 502 (7440). - P. 188-193. - DOI : 10.1038 / nature12617 . - PMID 24067611 .
- ↑ Burrow C., den Blaauwen J., Newman M., Davidson R. The diplacanthid fishes (Acanthodii, Diplacanthiformes, Diplacanthidae) from the Middle Devonian of Scotland // Palaeontologia Electronica , 2016, Article 19.1.10A. - P. 1-83.
- ↑ Family Ischnacanthidae Woodward, 1891 . // Website fossiilid.info . Date of treatment March 26, 2017.
- ↑ Voichyshyn V., Szaniawski H. Acanthodian Jaw Bones from Lower Devonian Marine Deposits of Podolia, Ukraine // Acta Palaeontologica Polonica , 2012, 57 (4). - P. 879-896. - DOI : 10.4202 / app.2011.0079 .
- ↑ 1 2 Valiukevičius J., Burrow C. J. Diversity of Tissues in Acanthodians with Nostolepis -type Histological Structure // Acta Palaeontologica Polonica , 2005, 50 (1). - P. 635-649.
Literature
- Berg L. S. The system of fish-like and fish, now living and fossil. 2nd ed. / Ch. ed. E.N. Pavlovsky . - M .: Publishing House of the Academy of Sciences of the USSR, 1955. - 286 p. - (Tr. Zool. Institute of the USSR Academy of Sciences. T. XX).
- Novitskaya L.I., Obruchev D.V. Class Acanthodei. Akantody // Fundamentals of paleontology. T. 11: Jawless and fish / Ed. Ed D.V. Obruchev . - M .: Nauka , 1964 .-- 521 p. - S. 175—194.
- Cherepanov G.O., Ivanov A.O. Paleozoology of vertebrates. - M .: Publ. Center "Academy", 2007. - 352 p. - ISBN 978-5-7695-3104-0 .
- Agassiz L. Recherches sur les poissons fossiles. Tome III. Contenant l'Histoire de l'Ordre des Placoïdes . - Neuchâtel: Imprimerie de Petitpierre, 1833-1843. - viii + 424 p.
- Nelson J. S. , Grande T. C., Wilson M. V. H. Fishes of the World. 5th ed . - Hoboken, New Jersey: John Wiley & Sons, 2016 .-- xli + 706 p. - ISBN 978-1-1183-4233-6 .
- Woodward A. S. Catalog of the fossil fishes in the British Museum (Natural History). Part II. Elasmobranchii (Acanthodii), Holocephali, ichthyodorulites, Ostracodermi, Dipnoi, and Teleostomi (Crossopterygii and chondrostean Actinopterygii) . - London: Taylor and Francis, 1891. - xli + 567 p.