A study on the mechanism of morphing features of tuna median fins during C-turns

Larvae of bony fish swim in the intermediate Reynolds number ( Re ) regime, using body- and caudal-fin undulation to propel themselves. They share a median fin fold that transforms into separate median fins as they grow into juveniles. The fin fold was suggested to be an adaption for locomotion in the intermediate Reynolds regime, but its fluid-dynamic role is still enigmatic. Using three-dimensional fluid-dynamic computations, we quantified the swimming trajectory from body-shape changes during cyclic swimming of larval fish. We predicted unsteady vortices around the upper and lower edges of the fin fold, and identified similar vortices around real larvae with particle image velocimetry. We show that thrust contributions on the body peak adjacent to the upper and lower edges of the fin fold where large left–right pressure differences occur in concert with the periodical generation and shedding of edge vortices. The fin fold enhances effective flow separation and drag-based thrust. Along the body, net thrust is generated in multiple zones posterior to the centre of mass. Counterfactual simulations exploring the effect of having a fin fold across a range of Reynolds numbers show that the fin fold helps larvae achieve high swimming speeds, yet requires high power. We conclude that propulsion in larval fish partly relies on unsteady high-intensity vortices along the upper and lower edges of the fin fold, providing a functional explanation for the omnipresence of the fin fold in bony-fish larvae.

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Muscles of Median Fins and Origin of Pectoral vs. Pelvic and Paired vs. Median Fins

Muscles of Chordates ◽

10.1201/b22498-14 ◽

2018 ◽

pp. 305-320

Author(s):

Rui Diogo ◽

Janine M. Ziermann ◽

Julia Molnar ◽

Natalia Siomava ◽

Virginia Abdala

Keyword(s):

Median Fins

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Hydrodynamic Analysis for the Morphing Median Fins of Tuna during Yaw Motions

Applied Bionics and Biomechanics ◽

10.1155/2021/6630839 ◽

2021 ◽

Vol 2021 ◽

pp. 1-15

Author(s):

Xiaohu Li

Keyword(s):

Numerical Method ◽

Hydrodynamic Forces ◽

The Body ◽

Robotic Fish ◽

Hydrodynamic Performance ◽

Hydrodynamic Analysis ◽

Dorsal Fin ◽

The Stability ◽

Median Fins

Tuna can change the area and shape of the median fins, including the first dorsal, second dorsal, and anal fins. The morphing median fins have the ability of adjusting the hydrodynamic forces, thereby affecting the yaw mobility of tuna to a certain extent. In this paper, the hydrodynamic analysis of the median fins under different morphing states is carried out by the numerical method, so as to clarify the influence of the erected median fins on the yaw maneuvers. By comparing the two morphing states of erected and depressed, it can be concluded that the erected median fins can increase their own hydrodynamic forces during the yaw movement. However, the second dorsal and anal fins have limited influence on the yaw maneuverability, and they tend to maintain the stability of tuna. The first dorsal fin has more lift increment in the erection state, which can obviously affect the hydrodynamic performance of tuna. Moreover, as the median fins are erected, the hydrodynamic forces of the tuna’s body increase synchronously due to the interaction between the body and the median fins, which is also very beneficial to the yaw motion. This study indicates that tuna can use the morphing median fins to adjust its mobility and stability, which provides a new idea for the design of robotic fish.

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Quebecius quebecensis (Whiteaves), a porolepiform crossopterygian (Pisces) from the Late Devonian of Quebec, Canada

Canadian Journal of Earth Sciences ◽

10.1139/e87-221 ◽

1987 ◽

Vol 24 (12) ◽

pp. 2351-2361 ◽

Cited By ~ 8

Author(s):

Hans-Peter Schultze ◽

Marius Arsenault

Keyword(s):

Ventral Side ◽

The Body ◽

Late Devonian ◽

Pectoral Fin ◽

Pectoral Fins ◽

Median Fins ◽

Pelvic Fin

Quebecius quebecensis (Whiteaves 1889) is a porolepiform crossopterygian related to Glyptolepis. A large nariodal, a large tabular, a separate intertemporal, and a large fused nasosupraorbital are features of Quebecius that characterize it as a porolepiform. The small size of the operculum, median extrascapular larger than the lateral one, small lower squamosals, and deep maxilla are additional features separating Quebecius from Glyptolepis. As in Glyptolepis, the median fins are not lobed. The pectoral fin possesses a long fleshy lobe. The internal, ventral side of the broadly based pelvic fin suggests that the internal axis has shifted towards the body. Pectoral fins with a long fleshy lobe are a common feature of porolepiforms, but lobed bases in the pelvic and unpaired fins are a feature found in Holoptychius, and not in Glyptolepis and Quebecius. Quebecius quebecensis is conspecific with Quebecius williamsi Schultze 1973, mistakenly described as an onychodont crossopterygian.

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Understanding Fish Linear Acceleration Using an Undulatory Biorobotic Model with Soft Fluidic Elastomer Actuated Morphing Median Fins

Soft Robotics ◽

10.1089/soro.2017.0085 ◽

2018 ◽

Vol 5 (4) ◽

pp. 375-388 ◽

Cited By ~ 12

Author(s):

Li Wen ◽

Ziyu Ren ◽

Valentina Di Santo ◽

Kainan Hu ◽

Tao Yuan ◽

...

Keyword(s):

Linear Acceleration ◽

Median Fins

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The Permo-Carboniferous genus Sagenodus and the beginning of modern lungfish

Contributions to Zoology ◽

10.1163/18759866-06701002 ◽

1997 ◽

Vol 67 (1) ◽

pp. 9-70 ◽

Cited By ~ 46

Author(s):

H.-P. Schultze ◽

J. Chorn

Keyword(s):

North America ◽

The Body ◽

Lower Permian ◽

Red Beds ◽

Faunal Assemblage ◽

Canal System ◽

Sensory Canal ◽

Shallow Marine ◽

Six Elements ◽

Median Fins

The lungfish Sagenodus is a widespread Permo-Carboniferous genus found in Europe and North America. Important localities in the U.S.A. include Middle Pennsylvanian coals near Linton, Ohio, Upper Pennsylvanian deposits near Robinson and Hamilton, Kansas, and Peoria, Illinois; Lower Permian sediments near Cameron, Ohio; and Lower Permian “Red Beds” of Texas and Oklahoma. At least three species of Sagenodus were present in North America S. copeanus, S. periprion, S. serratus). S. ohiensis is represented solely by one skull. Knowledge of the osteology of Sagenodus is enhanced by the study of well-preserved but disassociated elements from Robinson, Kansas (S. copeanus) and Little Bitter Creek, Texas (S. serratus). The orbital series is now known to be comprised of six elements and the sensory canal system is more complex than previously realized. The only known articulated skeleton of this genus, from Hamilton Quarry, Kansas, permits a restoration of the entire animal including the median fins. The dorsal and anal fins are not separate; there is instead, a continuous fin around the caudal end of the body, as found in other post-Devonian lungfishes. Sagenodus is structurally intermediate between more primitive Devonian dipnoans and post-Paleozoic lungfishes. Evident trends can be seen in the reduction of bone (both number of bones and degree of ossification), the loss of cosmine, the nature of the scales, the structure and histology of tooth plates, and the configuration of the median fins. Sagenodus is a member of a euryhaline faunal assemblage that can be found from shallow marine to freshwater deposits.

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Aspects of the postcranial skeleton of the Lower Permian lungfish, Gnathorhiza

Journal of Paleontology ◽

10.1017/s0022336000036623 ◽

1989 ◽

Vol 63 (6) ◽

pp. 919-930 ◽

Cited By ~ 6

Author(s):

Walter W. Dalquest ◽

M. John Kocurko ◽

John V. Grimes

Keyword(s):

Axial Skeleton ◽

Lower Permian ◽

Fish Scales ◽

Early Permian ◽

Postcranial Skeleton ◽

Caudal Fin ◽

North Central ◽

New Information ◽

Central Texas ◽

Median Fins

A newly discovered locality of aestivation burrow casts containing the lungfish, Gnathorhiza serrata, is reported from the early Permian Arroyo Formation of Wilbarger County, north-central Texas. Remains preserved in the burrow casts provide sections of mummified Gnathorhiza and new information about the postcranial skeleton of this fish. Scales of Gnathorhiza resemble those of the modern lungfishes such as Lepidosiren in their microanatomy. No traces of paddle-like pectoral or pelvic fins were found and paired fins of Gnathorhiza may have resembled those of Lepidosiren. The axial skeleton and median fins of Gnathorhiza seem to resemble those of Lepidosiren except that the tail area and caudal fin of Gnathorhiza were stout and strong rather than slender and tapering. Gnathorhiza, which aestivated tail-down in its burrow, may have required a stout tail for support.

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Dario neela, a new species of badid fish from the Western Ghats of India (Teleostei: Percomorpha: Badidae)

Zootaxa ◽

10.11646/zootaxa.4429.1.6 ◽

2018 ◽

Vol 4429 (1) ◽

pp. 141

Author(s):

RALF BRITZ ◽

V.K. ANOOP ◽

NEELESH DAHANUKAR

Keyword(s):

Western Ghats ◽

The Body ◽

Western Ghats Of India ◽

Tributary Stream ◽

Black Blotch ◽

Median Fins ◽

The Western Ghats ◽

A New Species ◽

Small Tributary ◽

Pelvic Fin

Dario neela, is described from a small tributary stream of the Kabini River in northern Kerala, India. It can be distinguished from congeners by the male colouration in life, which shows wide rims of iridescent blue in all median fins and the pelvic fin. It is further distinguished from all species of Dario, except D. urops by the number of abdominal vertebrae (14 vs. 11–13), and from all Dario species except D. urops and D. huli by the presence of a conspicuous black blotch on the caudal-fin base. Dario neela is distinguished from D. urops by the absence of the horizontal suborbital stripe and presence of a series of up to eight black bars on the body; and from D. huli by 27–28 vertebrae and 27 scales in a lateral row and the absence of teeth from hypobranchial 3. Dario neela is genetically divergent from both Western Ghats congeners in the mitochondrial CO1 gene, showing an uncorrected p-distance of 5.9% with D. urops and 13.1% to D. huli.

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Age and growth of Callionymus lyra L.

Journal of the Marine Biological Association of the United Kingdom ◽

10.1017/s0025315400012777 ◽

1951 ◽

Vol 30 (2) ◽

pp. 281-296 ◽

Cited By ~ 17

Author(s):

Hsiao-Wei Chang

Keyword(s):

Seasonal Variation ◽

Sexual Dimorphism ◽

West Africa ◽

Economic Importance ◽

Age And Growth ◽

Seasonal Abundance ◽

The Common ◽

Abundance And Distribution ◽

Median Fins ◽

European Seas

The Common Dragonet, Callionymus lyra L., is one of the commonest fishes in the Plymouth area, and is widely distributed in European seas. Recent reports indicate that it occurs also off the coast of West Africa (Fowler, 1936; Poll, 1949). This fish, like others of the genus, attracts attention because, although it has very little economic importance, it is strikingly coloured and the sexes are markedly different. Work has been done on the breeding by Holt (1897, 1898), and by Holt & Scott (1898); on ova and larvae by M'Intosh (1885), M'Intosh & Prince (1889), Cunningham (1891), Holt (1897), Ehrenbaum (1905–9), Fage (1918), Mielck (1925), Duncker, Ehrenbaum, Kyle, Mohr & Schnakenbeck (1929); on seasonal abundance and distribution of post-larvae off Plymouth by Russell (1930–47) and Corbin (1948); and on the skeleton by Günther (1861) and Ford (1937). The mature males are provided with remarkable secondary sexual characters both in coloration and in relative lengths of snout and of median fins, which render them so different from the females that they were originally regarded as different species and known as the Gemmeous Dragonet (male C. lyra L.) and the Sordid Dragonet (female C. lyra L.=C. dracunculus L.) respectively (Donovan, 1808; Yarrell, 1859; Couch, 1863). The sexual dimorphism and seasonal variation of this species has been much studied by Holt (1898), Smitt (1892–95), Gallien (1934), Letaconnoux (1949) and Desbrosses (1949). Very little information has so far been provided about its age and growth, with which the present paper deals.

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