Using the DLT Dataviewer 2 program in MATLAB version 7.10 (Hedrick, 2008), we digitized 31 points across the right pectoral fin and along the body midline, determining the x, y and z coordinates of each point in every frame via direct linear transformation to give fin surface deformations in 3-D (Fig. The movement of fish with special reference to the eel, The role of the fins in the equilibrium of the swimming fish. To determine wavespeed (v), we chose a known distance between points along an anteroposterior axis, and then divided that distance by the time required for a given wave (e.g. Animals have to move from one place to another for many reasons. Wavelength (λ) was determined by dividing mid-disc wavespeed (v) by mid-disc frequency (f), according to the wave function λ=v/f. Wavespeed and frequency are not reported for every point individually, as variations are subtle and require a pronounced (high amplitude) wave for reliable calculation. In this study we observe two patterns of distal fin curvature during pectoral fin swimming. Strouhal number was determined by fL/U, with disc length used as the characteristic length L. Wave number, defined as the number of waves present on the fin at one time, was calculated relative to both disc length and disc perimeter. Incorporating these findings into future models of undulating fins will allow further investigation of their hydrodynamic impacts; 3-D studies of other undulators may reveal convergent locomotor strategies for waveform modulation. In actinopterygians, the jointed, bilaminar structure of lepidotrichia translates small changes in the length of muscles at the fin base into dramatic fin curvature (Alben et al., 2007; Geerlink and Videler, 1986). Batoid fin elements lack the bilaminar structure of actinopterygian fin rays and, as seen in T. lymma, the muscles that control fin adduction/abduction are not confined to the fin base but extend across the full length of the fin radials (Rosenberger and Westneat, 1999). As the cycle progresses, the wave passes along the pectoral fin, increasing in amplitude (25–75% of the finbeat), then passing off the posterior margin of the disc (100% of the finbeat). Many Benthic rays have adapted to be incredibly stealthy, they have a low profile and create very little disturbance when they move. For comparison with 2-D kinematic data from previous work (e.g. 9B). All variables increase from left to right along canonical 1. 2.1 Support and Locomotion inHumans and Animals Importance of support and locomotion Search for food Provide protection by escaping from enemies or avoiding danger Search for more conducive living environment Find mates for reproduction Avoid … Future studies calculating this value should consider the path of wave travel when selecting a method of standardization. Only a relatively small region of the pectoral fin (~25%) undulates with significant amplitude (>0.5 cm). Primates with remarkably few changes in their skeletons and musculature have adopted a bewildering variety of locomotor … When travelling in the same direction of a wave it has been shown that they will increase their speed while reducing the amplitude of their fins which indicates that they may use travelling waves to increase their swimming efficiency. Contrary to some findings for T. lymma (Rosenberger and Westneat, 1999), amplitude does not vary between swimming speeds in P. orbignyi, whether considered as maximum amplitude, mid-disc amplitude or for any point across the disc (all P>0.05; Fig. Movement is important! Lighthill's original discussion of narrow-necking is in relation to the caudal Loco Motion (Youth Group), a film and media club based in Essex, UK Games. Models of knifefish (Curet et al., 2011), undulatory rays and ray-like fins (Low, 2006; Clark and Smits, 2006) may be based on different organisms, but they share the same underlying principle: locomotion is controlled by a single undulating surface, with modulations of the wave function producing steady swimming, acceleration or more complex maneuvers. [4], Rays are at a disadvantage compared to other fish when it comes to maneuverability. Mid-disc wavespeed increased by the same proportion (31.00±2.53 to 46.02±3.25 cm s−1; ANOVA, P<0.01; Fig. The mediolateral trend reflects increasing angular displacement with distance from the midline (Fig. Unlike Rajiformes and Myliobatiformes their propulsion comes solely from the movement of their caudal fin, which is much more developed than in skates and rays. One camera captured a dorsal view via a 45 deg angled mirror positioned above the flow tank, and the remaining two cameras were set off-axis from dorsal and lateral positions. These multiple control surfaces work in combination to produce thrust and balance torques in steady swimming, to maneuver and, at evolutionary time scales, may offer redundant systems, allowing one set of fins to specialize for a particular function while others drive locomotion (e.g. Locomotion definition, the act or power of moving from place to place. review the field’s progress in birds and mice, assessing emerging new technologies and asking critical questions for the future. The DFA correctly identified the swimming speed of 100% of sequences based on frequency and wavespeed data, but was also influenced by mid-disc amplitude and wavelength values despite the lack of significant by-speed differences in the latter two variables when considered independently (ANOVA; Fig. This same form of locomotion may be used to try to scare away predators. Arts, entertainment, and media Clubs. Our staff is made up of amazing Baja residents who want to share their beloved city with you! However, the broad, dorsoventrally compressed stingray body has ample inertia and added mass to resist recoil forces, and any drag reduction benefit from restricted amplitude is more likely to result from a decrease in projected area, compared with the anguilliform pattern of continuous amplitude increase. Bottom locomotion Small flatworms (Platyhelminthes) and some of the smaller molluscan species move along the bottom by ciliary activity. 9A) underestimate curvature because of the limited resolution available given the number of points digitized on the distal fin, but we observed dramatic distal curvature directly (Fig. Disclaimer: The Animal Diversity Web is an educational resource written largely by and for college students.ADW doesn't cover all species in the world, nor does it include all the latest scientific information about organisms we describe. Most batoids do use their pectoral fins to swim, with the exception of body-caudal fin propulsion by guitarfish (Rhiniformes and Rhynchobatiformes; Klausewitz, 1965) and torpedo rays (Torpediniformes; Roberts, 1969). Different parts of the disc are considerably more flexible than others and some parts are designed to passively deform. Rajiforms are distinguished by the presence of greatly enlarged pectoral fins, which reach as far forward as the sides of the head, with a generally flattened body. 8). The asymptotic amplitude pattern we observe in P. orbignyi would reduce projected area, even without the posterior decrease seen in T. lymma: as amplitude nears the asymptote, projected area does not increase further. Minimizing the undulation of the anterior fin during locomotion creates a stable leading edge, streamlining the shape of the body as projected into the water flow, reducing flow separation and drag. However, these technologies are not developed to the point where they can fully imitate actual muscles. Therefore, curvature changes direction between upstroke and downstroke. Rosenberger (Rosenberger, 2001) identified a continuum of batoid locomotion between oscillation and undulation, with species' position between the two extremes defined by the number of waves present on the pectoral fin at one time; undulators have more than one wave, oscillators less than one. Katsufumi Sato tells us about his research experiences around Japan and in Antarctica investigating the behaviour of top marine predators, and describes how his data logging devices have sparked global collaborations. Rajiformes is one of the four orders in the superorder Batoidea, flattened cartilaginous fishes related to sharks. Along the anteroposterior axis, amplitude increases to its maximum value just posterior to mid-disc (at 0.7 DL), and remains near this asymptote from 0.5 to 1.0 DL (Fig. Individual stingrays were filmed during steady swimming at two speeds, 1.5 and 2.5 DL s−1 (approximately 0.20 and 0.33 m s−1, respectively). In that study, a motion program in which the dorsal and ventral margins of the caudal fin lead the middle of the fin during swimming results in the caudal fin surface cupping into the flow. Frequency-driven increases in velocity do not increase projected area, and are therefore employed by many swimmers as a more efficient means of increasing thrust. Potamotrygon orbignyi is clearly an undulatory swimmer; images of swimming rays reveal significantly more than one wave present on the pectoral fin (Fig. [2], The pectoral fins of a mobuliform swimming ray experience a spanwise dorsoventral deformation that is highest at the tip and a chord-wise traveling wave. Given the flexibility of the stingray pectoral disc, it is not surprising that fin modulations may be subtle. [14] For all points except one, amplitudes remain constant across swimming speeds (ANOVA, P>0.05); the exceptional point is located just distal to the tail, where the pectoral fin forms a lobe at its posterior margin, with an amplitude inversely correlated to swimming speed, decreasing from 0.88±0.07 to 0.58±0.05 cm (ANOVA, P<0.01). Both of these are brought about by the jointefforts of the skeletal and muscular systems. was measured from the most anterior point on the stingray snout to the posterior margin of the pectoral fin disc, and is equivalent to chord length. Supplementary material available online at One thing that really sets the performance of the biological and artificial versions apart is the nuanced flexibility and actuation of the disc. Spanwise amplitude variation along the mediolateral axis at positions indicated on the stingray image. Studies of mobuliform locomotion have found surprising maneuverability and efficiency in manta rays and other, typically large, ‘underwater fliers’ (Heine, 1992; Parson et al., 2011); the charismatic manta is the basis of several bio-inspired robots (e.g. We chose to work with juvenile potamotrygonids because their small size [mean pectoral disc length (DL) 12.8±0.8 cm, mean disc width (DW) 11.27±0.99 cm] allowed the study of undulatory swimming in a small, controlled volume, yielding high-resolution kinematic data. Along the anteroposterior axis, amplitude increases until the wave reaches mid-disc and then remains constant, in contrast to angulliform patterns of continuous amplitude increase. This type of movement also helps when they are underground in a tunnel. (One finbeat was defined as a full cycle of the propulsive wave.) Locomotion due to the Movement of Appendages (Fins): Turning to the second of primary methods of locomotion, it may be noted that although fins are very characteristic parts of fishes, many species can get along remarkably well without them. N=12 for all variables at each swimming speed. with less than one waveform present on the fin at a time. Although the mean value of 59±4% suggests a relatively even division of cycle time between positive and negative curvature, values range widely from 30 to 93%, and in almost one-third of sequences the fin is negatively curved for more than 75% of the cycle. Moored et al., 2011). 6). They use their wing-like pectoral fins to propel themselves through the water. 9A). 11). The magnitude of the asymptote varies with position from the midline (due to varying angular displacement), but the pattern holds across the entire disc, in an interesting complement to patterns of amplitude increase found for other undulating swimmers. [7], In a pelagic environment rays will encounter surface waves. 2. They can’t stay in one place in order to support their living. In contrast, rays (Batoidea) perform virtually all behaviors using a single broad surface: the distinctive, expanded pectoral fins. ], in addition to support from the Harvard University Department of Organismic and Evolutionary Biology, NSF-IGERT Training Grant in Biomechanics and Robert A. Chapman Memorial Scholarship [to E.L.B.]. The dramatic undulations of stingray pectoral fins draw attention from any observer – the entire fin initially appears to be involved in a high-amplitude wave (Figs 2, 3). Wake structure, Escaping Flatland: three-dimensional kinematics and hydrodynamics of median fins in fishes, Hydrodynamics and energetics of fish propulsion, Function of the heterocercal tail in sharks: quantitative wake dynamics during steady horizontal swimming and vertical maneuvering, Prey handling using whole-body fluid dynamics in batoids, Suppression of the von Kármán vortex street behind a circular cylinder by a travelling wave generated by a flexible surface, Oxygen limitation fails to explain upper chronic thermal limits and the temperature size rule in mayflies, Acclimation to warm temperatures has important implications for mitochondrial function in Atlantic salmon (,, Rajiform locomotion: three-dimensional kinematics of the pectoral fin surface during swimming in the freshwater stingray Potamotrygon orbignyi, In the field: an interview with Katsufumi Sato, The mysterious case of the cassowary casque, preLights – From flying aces to soar losers, Neuronal circuits and the magnetic sense: central questions. Complex deformations of the broad, flexible pectoral fins occur as the undulating wave varies in three dimensions; pectoral fin kinematics and changes in waveform with swimming speed cannot be fully quantified by two-dimensional analyses of the fin margin. Locomotion due to the Movement of Appendages (Fins): Turning to the second of primary methods of locomotion, it may be noted that although fins are very characteristic parts of fishes, many species can get along remarkably well without them. We’re intent on supporting the local community we love. Of the four orders of Batoidae this holds truest for the Myliobatiformes (rays) and the Rajiformes (skates). See more. In addition to the anteroposterior bending that accompanies the propulsive wave, stingray fins show mediolateral curvature, with a maximum of 0.06±0.02 mm−1 in both positive (concave up) and negative (concave down) directions (Fig. Our data contradict this idea: potential excursion should correspond to angular displacement, increasing with fin span, yet maximum amplitude occurs posterior to the maximum disc width (0.7 versus 0.5 DL). In the first case, the lateral edge of the fin bends away from the direction of motion, trailing the main portion of the fin. 2). We thank E. M. Standen, J. Lim, N. Danos and B. Flammang-Lockyer for helpful conversations during both the data collection and analysis phases of this work, as well as A. Stubbs for assistance during experiments. Another word for locomotion. 10A,B). 5B; ANOVA, P=0.48). Error bars represent ±1 s.e.m. The back of it has an anchor point that is used to pull it forward. Among undulating batoids, stingrays and freshwater stingrays (Dasyatidae and Potamotrygonidae) both have reduced cartilage calcification in the distal fin relative to medial positions, reducing fin stiffness near the margin (Schaefer and Summers, 2005). The variability in curvature pattern is interesting. Most Batoids exhibit median paired fin swimming, utilizing their enlarged pectoral fins. Scale bar (for the stingray image), 1 cm. 11B). Definition of rajiformes in the dictionary. However, as the effect of body depth is constant between speeds, the positive correlation between body angle and swimming speed stands. What does rajiformes mean? 4A), excepting one point near the posterior margin, which is unlikely to play a significant role in propulsion, though it may influence flow separation from the fin. 11A). (B) Discriminant function plot separating swimming speeds along canonical 1 (100% correct classifications), with major influences of mid-disc wavespeed and mid-disc frequency, and secondary influences of mid-disc amplitude, body angle and wavelength. Batoids are a superorder of cartilaginous fish consisting of skates, rays and other fish all characterized by dorsoventrally flattened bodies and large pectoral fins fused to the head. At mid-disc (maximum disc width), the wave has a mean amplitude of 1.41±0.06 cm, increasing to a maximum amplitude of 1.66±0.04 cm They are highly efficient open water swimmers capable of traversing great distances at high speeds. However, overall findings for body angle are not reflected by the particular sample images and view angles used here. Unlike other fishes, which typically interact with the fluid environment via multiple fins, undulating rays modulate a single control surface, the pectoral disc, to perform pelagic locomotion, maneuvering and other behaviors. 5A). Position markers are positioned halfway between the two digitized points used to calculate each local wavespeed. Batoids have certain characteristics that would be desirable in an underwater unmanned vehicle. locomotion definition: 1. the ability to move 2. the ability to move 3. the ability to move; movement. This family of batoids exhibits pelvic fins that appear to be specialized for walking − alternating one The complex actuation of the wings has been mimicked successfully through a variety of means including tensegrity structures, electroactive polymers, and fluid muscles. Body angle increases as stingrays swim faster, from 5.1±1.1 to 7.8±0.7 deg (ANOVA, P<0.05), though this finding is not illustrated by the particular sample images and view angles depicted in Fig. For clarity, the vertical axis is elongated by a factor of three relative to true aspect ratio. [8], Rajiform swimmers move by undulating the distal parts of their pectoral fins with multiple waveforms present on the fin at a time. Remember, there are different types of fundamental movement. ‘Higher-level control of locomotion seems to be more important for humans than for cats.’ ‘As her pain made locomotion distressing, the father had to carry his daughter home.’ ‘These life forms most likely have appendages for the purpose of locomotion.’ ‘The walking gait maneuver is the body's natural means of locomotion.’ Thank you for your interest in spreading the word on Journal of Experimental Biology. Previous work on undulating rays has described the propulsive wave in terms of the motion of a single point at the fin margin (Rosenberger, 2001), or several points along the margin (Rosenberger and Westneat, 1999), but has not explored the pectoral fin as an undulating surface. This question is for testing whether or not you are a human visitor and to prevent automated spam submissions. 4A). [11] As such swimming away from the substrate for extended periods is unsustainable. This distinctive morphology has resulted in several unique forms of locomotion. There are animals that move on land, in the air, in trees, and in the water. Calculated values (Fig. Columns illustrate the two major patterns of curvature through one wave cycle: (B) concave down on upstroke, concave up on downstroke, and (C) concave down on upstroke and downstroke. Scale bar, 1 cm. Camera height and angles ensured that all portions of the stingray pectoral fin were visible in at least two camera views throughout each finbeat. From muscle fiber analysis it appears that punting may be a primary mode of transportation at low speeds (about 1/3 Body lengths per second) in some skates and rajiform locomotion may be used when for specific situations. In general, animals require locomotion for defence, searching for food and shelter. Locomotion and Movement - A captivating lesson of human anatomy which includes different muscles, bones, joints present in a human body etc. The word locomotion is derived from the Latin word locus (place) and motio (motion) which means movement from place to place. When wave number is calculated relative to disc length (sensu Rosenberger, 2001), our data yield a wave number of 1.10±0.08 for P. orbignyi, representing just over one complete wave on the Natural pigmentation markings on the dorsal surface of the pectoral fin allowed the same points to be reliably identified in each camera view. In normal locomotion the anterior edge of the foot is lifted and detached from the substrate. Amplitude increases between 0.3 and ~0.5 DL; the rate of increase slows as the wave moves towards the posterior region of the fin, approaching an asymptote. Illustration of P. orbignyi swimming at (A) 1.5 disc lengths (DL) s−1 and (B) 2.5 DL s−1, at intervals of 25% of one finbeat. For each swimming sequence, mean values were determined for kinematic variables including the amplitude, frequency, wavespeed and wavelength of the propulsive wave, plus the whole-body angle of attack and spanwise fin curvature. Increases in swimming speed are driven by both wave frequency and wavespeed, though multivariate analyses reveal a secondary role for amplitude. (Taft et al., 2008) found to influence pectoral fin motion in sculpin. Humans are limited to terrestrial locomotion on two limbs or swimming with all four limbs. Constraints in fin undulation result from a combination of morphological and hydrodynamic factors. [12], The majority of electric rays have a distinctive style of low speed swimming that consists of periodically moving up in the water column then gliding back down. across the fin surface (Fig. In addition, fin elements bifurcate near the distal margin, further altering fin stiffness (Schaefer and Summers, 2005). WALKING is shifting one’s weight from one foot to the other. ; N=12. In eels, amplitude increases continuously along the entire length of the body, without asymptote (Gillis, 1996; Gray, 1933). Order: Rajiformes Family: Rajidae: Body Plan: - Skate are cartilaginous fish that lack any "true bone". Wind tunnel tests on a model of, Software techniques for two- and three-dimensional kinematic measurements of biological and biomimetic systems.