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

1987 ◽  
Vol 24 (12) ◽  
pp. 2351-2361 ◽  
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.

scholarly journals Molecular mechanisms underlying the exceptional adaptations of batoid fins

2015 ◽  
Vol 112 (52) ◽  
pp. 15940-15945 ◽  
Author(s):  
Tetsuya Nakamura ◽  
Jeff Klomp ◽  
Joyce Pieretti ◽  
Igor Schneider ◽  
Andrew R. Gehrke ◽  
...  
Keyword(s):  
Molecular Mechanisms ◽  
Integration Site ◽  
The Body ◽  
Pectoral Fin ◽  
Pectoral Fins ◽  
Bony Fishes ◽  
Genetic Module ◽  
Fin Development ◽  
Pelvic Fin

Extreme novelties in the shape and size of paired fins are exemplified by extinct and extant cartilaginous and bony fishes. Pectoral fins of skates and rays, such as the little skate (Batoid, Leucoraja erinacea), show a strikingly unique morphology where the pectoral fin extends anteriorly to ultimately fuse with the head. This results in a morphology that essentially surrounds the body and is associated with the evolution of novel swimming mechanisms in the group. In an approach that extends from RNA sequencing to in situ hybridization to functional assays, we show that anterior and posterior portions of the pectoral fin have different genetic underpinnings: canonical genes of appendage development control posterior fin development via an apical ectodermal ridge (AER), whereas an alternative Homeobox (Hox)–Fibroblast growth factor (Fgf)–Wingless type MMTV integration site family (Wnt) genetic module in the anterior region creates an AER-like structure that drives anterior fin expansion. Finally, we show that GLI family zinc finger 3 (Gli3), which is an anterior repressor of tetrapod digits, is expressed in the posterior half of the pectoral fin of skate, shark, and zebrafish but in the anterior side of the pelvic fin. Taken together, these data point to both highly derived and deeply ancestral patterns of gene expression in skate pectoral fins, shedding light on the molecular mechanisms behind the evolution of novel fin morphologies.

Fluid dynamics of flapping aquatic flight in the bird wrasse:three-dimensional unsteady computations with fin deformation

2002 ◽  
Vol 205 (19) ◽  
pp. 2997-3008 ◽  
Author(s):  
Ravi Ramamurti ◽  
William C. Sandberg ◽  
Rainald Löhner ◽  
Jeffrey A. Walker ◽  
Mark W. Westneat
Keyword(s):  
Fluid Dynamics ◽  
Steady State ◽  
Three Dimensional ◽  
Force Production ◽  
Time History ◽  
The Body ◽  
Vertical Acceleration ◽  
Field Variation ◽  
Pectoral Fin ◽  
Pectoral Fins

SUMMARY Many fishes that swim with the paired pectoral fins use fin-stroke parameters that produce thrust force from lift in a mechanism of underwater flight. These locomotor mechanisms are of interest to behavioral biologists,biomechanics researchers and engineers. In the present study, we performed the first three-dimensional unsteady computations of fish swimming with oscillating and deforming fins. The objective of these computations was to investigate the fluid dynamics of force production associated with the flapping aquatic flight of the bird wrasse Gomphosus varius. For this computational work, we used the geometry of the wrasse and its pectoral fin,and previously measured fin kinematics, as the starting points for computational investigation of three-dimensional (3-D) unsteady fluid dynamics. We performed a 3-D steady computation and a complete set of 3-D quasisteady computations for a range of pectoral fin positions and surface velocities. An unstructured, grid-based, unsteady Navier—Stokes solver with automatic adaptive remeshing was then used to compute the unsteady flow about the wrasse through several complete cycles of pectoral fin oscillation. The shape deformation of the pectoral fin throughout the oscillation was taken from the experimental kinematics. The pressure distribution on the body of the bird wrasse and its pectoral fins was computed and integrated to give body and fin forces which were decomposed into lift and thrust. The velocity field variation on the surface of the wrasse body, on the pectoral fins and in the near-wake was computed throughout the swimming cycle. We compared our computational results for the steady, quasi-steady and unsteady cases with the experimental data on axial and vertical acceleration obtained from the pectoral fin kinematics experiments. These comparisons show that steady state computations are incapable of describing the fluid dynamics of flapping fins. Quasi-steady state computations, with correct incorporation of the experimental kinematics, are useful when determining trends in force production, but do not provide accurate estimates of the magnitudes of the forces produced. By contrast, unsteady computations about the deforming pectoral fins using experimentally measured fin kinematics were found to give excellent agreement, both in the time history of force production throughout the flapping strokes and in the magnitudes of the generated forces.

scholarly journals New species of Cetopsidium (Siluriformes: Cetopsidae: Cetopsinae) from the upper rio Branco system in Guyana

2009 ◽  
Vol 7 (3) ◽  
pp. 289-293 ◽  
Author(s):  
Richard P. Vari ◽  
Carl J. Ferraris Jr.
Keyword(s):  
New Species ◽  
River Basin ◽  
Amazon Basin ◽  
River System ◽  
The Body ◽  
Dna Barcodes ◽  
Pectoral Fins ◽  
Pelvic Fin

Cetopsidium soniae, new species, is described from the Takutu River basin of southwestern Guyana, within the upper portions of the rio Branco of the Amazon basin. The new species differs from its congeners in details of pigmentation, the length of the pelvic fin, the form of the first rays of the dorsal and pectoral fins in mature males, the relative alignment of the dorsal and ventral profiles of the postdorsal portion of the body, the position of the anus, and the depth of the body. DNA barcodes were generated for the holotype and paratype. An examination of other samples of Cetopsidium from the rio Branco system extends the range of C. pemon into the Ireng River system of Guyana.

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

Zootaxa ◽  
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. 

Swimming in needlefish (Belonidae): anguilliform locomotion with fins

2002 ◽  
Vol 205 (18) ◽  
pp. 2875-2884 ◽  
Author(s):  
James C. Liao
Keyword(s):  
Surface Waters ◽  
High Speed ◽  
Total Body Length ◽  
The Body ◽  
Pectoral Fins ◽  
Half Wavelength ◽  
Total Body ◽  
Length Analysis ◽  
Median Fins ◽  
Tail Beat

SUMMARYThe Atlantic needlefish (Strongylura marina) is a unique anguilliform swimmer in that it possesses prominent fins, lives in coastal surface-waters, and can propel itself across the surface of the water to escape predators. In a laboratory flow tank, steadily swimming needlefish perform a speed-dependent suite of behaviors while maintaining at least a half wavelength of undulation on the body at all times. To investigate the effects of discrete fins on anguilliform swimming, I used high-speed video to record body and fin kinematics at swimming speeds ranging from 0.25 to 2.0 Ls-1 (where L is the total body length). Analysis of axial kinematics indicates that needlefish are less efficient anguilliform swimmers than eels, indicated by their lower slip values. Body amplitudes increase with swimming speed, but unlike most fishes, tail-beat amplitude increases linearly and does not plateau at maximal swimming speeds. At 2.0 Ls-1, the propulsive wave shortens and decelerates as it travels posteriorly, owing to the prominence of the median fins in the caudal region of the body. Analyses of fin kinematics show that at 1.0 Ls-1 the dorsal and anal fins are slightly less than 180° out of phase with the body and approximately 225° out of phase with the caudal fin. Needlefish exhibit two gait transitions using their pectoral fins. At 0.25 L s-1, the pectoral fins oscillate but do not produce thrust, at 1.0 L s-1 they are held abducted from the body,forming a positive dihedral that may reduce rolling moments, and above 2.0 L s-1 they remain completely adducted.

scholarly journals A mechanical piston action may assist pelvic–pectoral fin antagonism in tree-climbing fish

2017 ◽  
Vol 98 (8) ◽  
pp. 2121-2131 ◽  
Author(s):  
Adhityo Wicaksono ◽  
Saifullah Hidayat ◽  
Bambang Retnoaji ◽  
Adolfo Rivero-Müller ◽  
Parvez Alam
Keyword(s):  
Finite Element ◽  
Energy Saving ◽  
Finite Element Simulations ◽  
Morphological Investigation ◽  
Pectoral Fin ◽  
Terrestrial Locomotion ◽  
Pectoral Fins ◽  
Biomimetic Robots ◽  
The Relationship ◽  
Pelvic Fin

In this research, we compared the anatomy and biomechanics of two species of mudskipper vs an aquatic sandgoby in view of terrestrial locomotion. Of particular interest was the relationship (if any) of pectoral fin movement with pelvic fin movement. We show that the pelvic fins of the terrestrial mudskippers studied herein, are retractable and move antagonistically with the pectoral fins. The pelvic fin of the sandgoby studied here is contrarily non-retractable and drags on any underlying substrate that the sandgoby tries to crawl across. We find that the pelvic and pectoral fin muscles of all fish are separated, but that the pectoral fins of the mudskipper species have bulkier radial muscles than the sandgoby. By coupling a detailed morphological investigation of pectoral-pelvic fins musculature with finite element simulations, we find that unlike sandgobies, the mudskipper species are able to mechanically push the pelvic fins downward as pectoral fins retract. This allows for an instant movement of pelvic fins during the pectoral fin backward stroke and as such the pelvic fins stabilize mudskippers through Stefan attachment of their pelvic fins. This mechanism seems to be efficient and energy saving and we hypothesize that the piston-like action might benefit pelvic–pectoral fin antagonism by facilitating a mechanical down-thrust. Our research on the biomechanics of tree-climbing fish provides ideas and greater potential for the development of energetically more efficient systems of ambulation in biomimetic robots.

Ituglanis paraguassuensis sp. n. (Teleostei: Siluriformes: Trichomycteridae):  a new catfish from the rio Paraguaçu, northeastern Brazil

Zootaxa ◽  
2007 ◽  
Vol 1471 (1) ◽  
pp. 53 ◽  
Author(s):  
RAFAEL M. CAMPOS-PAIVA ◽  
WILSON J.E.M. COSTA
Keyword(s):  
New Species ◽  
Color Pattern ◽  
The Body ◽  
The Other ◽  
Northeastern Brazil ◽  
Posterior Edge ◽  
Pectoral Fin ◽  
Other Hand ◽  
Pelvic Fin

Ituglanis paraguassuensis, new species, is described from the rio Paraguaçu, Bahia, northeastern Brazil. It is distinguished from the remaining species of the genus by the following combination of characters: color pattern composed of several irregular pale brown blotches aligned along the body (Fig. 1), parietal fontanel extending to posterior edge of medial parietal border (Fig. 2), pectoral fin i,6, pelvic fin i,4 and the unusual reduced number of vertebrae 34–36. Some of these features are considered to be plesiomorphic within the genus. On the other hand, I. paraguassuensis shares several features with members of the derived TSVSG clade. Comparisons with others trichomycterids are presented, including a detailed description and illustration of the body and skeleton including the laterosensory canal and cephalic pores.

scholarly journals Station-Holding by three Species of Benthic Fishes

1989 ◽  
Vol 145 (1) ◽  
pp. 303-320 ◽  
Author(s):  
PAUL W. WEBB
Keyword(s):  
Friction Coefficient ◽  
Smooth Surface ◽  
The Body ◽  
Published Data ◽  
High Lift ◽  
Posterior Portion ◽  
Drag Coefficients ◽  
Pectoral Fins ◽  
Benthic Fishes ◽  
Median Fins

Station-holding performance was determined on a smooth substratum and on a grid substratum for three species of benthic fishes differing in body shape, surface texture, density, friction coefficient and behavioural repertoire. The grid was made of wires parallel to the flow, which raised fish into the free stream. Limited observations were also made on the benthopelagic cod. Station-holding performance was evaluated at two speeds. The first was defined as the slip speed, above which activities such as swimming, fin-beating, body arching, body clamping and gripping the substratum were required to hold position on the substratum. The second was defined as the swim speed, when fish began swimming out of ground contact. Cod and lasher started swimming when they began slipping, so that slip and swim speeds were the same, averaging 6cms−1 for cod and 32cms−1 for lasher on the smooth surface. Body postures and fin-beating delayed swimming from a slip speed of about 20cms−1 to swim speeds of 47–58cms−1 for plaice and rays. The grid had relatively little effect on slip and swim speeds of plaice and rays. Lasher grasped the grid with their pectoral fins, increasing swim speeds to 55cms−1. Amputation of the posterior portion of the median fins of plaice reduced swim speeds on the smooth surface to 36cms−1. Amputation of the pectoral fins of lasher reduced the swim speed on the grid to 38cms−1. Estimates of drag coefficients for fish were made using published data for blisters. These were used to determine lift coefficients and the effects of grasping the substratum on the friction coefficient. Comparison of lift coefficients of rays on the smooth substratum with those on the grid showed that flow beneath the body reduced lift. Amputation of the posterior of the median fins of plaice and the rarity of body posturing by plaice and rays on the grid showed that the major role of this station-holding behaviour was reduction of lift through induction of flow beneath the body. Lashers were able to hold station at speeds comparable to plaice and rays when they could utilize the small amount of surface structure of the grid to increase friction. Benthic fishes tend to have either ‘flattened’ plaice- or ray-like forms with low drag coefficients but high lift coefficients, or more fusiform lasher-like forms with high drag coefficients and low lift coefficients. High-lift forms use behaviour to reduce lift coefficients, whereas high-drag forms use behaviour to increase friction.

Description of a new snake eel Ophichthus olivaceus (Teleostei: Anguilliformes, Ophichthidae) from the Red Sea

Zootaxa ◽  
2020 ◽  
Vol 4750 (1) ◽  
pp. 31-48
Author(s):  
JOHN E. McCOSKER ◽  
SERGEY V. BOGORODSKY ◽  
AHMAD O. MAL ◽  
TILMAN J. ALPERMANN
Keyword(s):  
Red Sea ◽  
Pectoral Fin ◽  
Mitochondrial Coi ◽  
Pectoral Fins ◽  
Dorsal Fin ◽  
Lower Jaw ◽  
Coi Barcoding ◽  
The Indian Ocean ◽  
Median Fins ◽  
A New Species

A new species of snake eel Ophichthus olivaceus is described based on two specimens trawled from a depth of 35–63 m from a soft substratum off Jizan, Red Sea coast of southern Saudi Arabia. It differs from its congeners by the following combination of characters: vertebrae 141–145; tail moderately short (2.15 in TL); head short (9.6–11.1 in TL); uniserial teeth in jaws and on vomer; pectoral fins slightly elongate, not lanceolate, upper rays longer than the lower; dorsal-fin origin above middle of pectoral fin; and a generally uniform, dark tan body with an olivaceous hue shading to tan or pale orange ventrally, with two pale yellow blotches above pectoral-fin base, snout and lower jaw dark brown, and olivaceous median fins. Its divergence from other mitochondrial-analyzed species is shown by phylogenetic analysis of the mitochondrial COI barcoding region. A key to the Indian Ocean species is provided. 

Design and Analysis of a Wire-Driven Robot Tadpole

2012 ◽  
Author(s):  
Zheng Li ◽  
Wenqi Gao ◽  
Ruxu Du ◽  
Baofeng Liao
Keyword(s):  
Control System ◽  
Body Length ◽  
Power Supply ◽  
The Body ◽  
Pectoral Fin ◽  
Caudal Fin ◽  
Moving Direction ◽  
And Control ◽  
System Power ◽  
Pelvic Fin

Besides fish there are a lot of animals can swim effectively in the water, such as tadpole. Different from fishes using multiple fins to swim, tadpole has only one tail. It is well known that most fish employ the caudal fin to generate thrust, and use the pectoral fin, pelvic fin, etc. to balance the body and control its moving direction. However, the tadpole fulfilled all these tasks by the tail only. Hence, it is interesting to build a robot tadpole and study its motion. In this paper, a robot tadpole is designed. It has a blunt head and a tail. The control system, power supply and actuator are inside the head. The tail is a novel wire driven flapping propeller. The tail has a serpentine backbone with 7 joints, which are controlled by just one actuator. A prototype is built. The overall length of the robot tadpole is 328cm. Experiment results show that the robot tadpole can swim freely in the water. Its speed is affected by the flapping amplitude and frequency. In the experiments, the tadpole’s speed can reach 0.413 body length per second (BL/s), which matches the prediction from the propulsion model.

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