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Li P, Xiong C, Huang B, Sun B, Gong X. Terrestrial locomotion characteristics of climbing perch (Anabas testudineus). J Exp Biol 2024; 227:jeb247238. [PMID: 38752366 DOI: 10.1242/jeb.247238] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2023] [Accepted: 05/01/2024] [Indexed: 06/07/2024]
Abstract
The evolution and utilization of limbs facilitated terrestrial vertebrate movement on land, but little is known about how other lateral structures enhance terrestrial locomotion in amphibian fishes without terrestrialized limb structures. Climbing perch (Anabas testudineus) exhibit sustained terrestrial locomotion using uniaxial rotating gill covers instead of appendages. To investigate the role of such simple lateral structures in terrestrial locomotion and the motion-generating mechanism of the corresponding locomotor structure configuration (gill covers and body undulation), we measured the terrestrial kinematics of climbing perch and quantitatively analysed its motion characteristics. The digitized locomotor kinematics showed a unique body postural adjustment ability that enables the regulation of the posture of the caudal peduncle for converting lateral bending force into propulsion. An analysis of the coordination characteristics demonstrated that the motion of the gill cover is kinematically independent of axial undulation, suggesting that the gill cover functions as an anchored simple support pole while axial undulation actively mediates body posture and produces propulsive force. The two identified feature shapes explained more than 87% of the complex lateral undulation in multistage locomotion. The kinematic characteristics enhance our understanding of the underlying coordinating mechanism corresponding to locomotor configurations. Our work provides quantitative insight into the terrestrial locomotor adaptation of climbing perch and sheds light on terrestrial motion potential of locomotor configurations containing a typical aquatic body and restricted lateral structure.
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Affiliation(s)
- Peimin Li
- Institute of Medical Equipment Science and Engineering, School of Mechanical Science and Engineering , Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Caihua Xiong
- Institute of Medical Equipment Science and Engineering, School of Mechanical Science and Engineering , Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Bo Huang
- Institute of Medical Equipment Science and Engineering, School of Mechanical Science and Engineering , Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Baiyang Sun
- Institute of Medical Equipment Science and Engineering, School of Mechanical Science and Engineering , Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Xuan Gong
- Institute of Medical Equipment Science and Engineering, School of Mechanical Science and Engineering , Huazhong University of Science and Technology, Wuhan, Hubei, China
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2
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Linden TJ, Burtner AE, Rickman J, McFeely A, Santana SE, Law CJ. Scaling patterns of body plans differ among squirrel ecotypes. PeerJ 2023; 11:e14800. [PMID: 36718452 PMCID: PMC9884040 DOI: 10.7717/peerj.14800] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2022] [Accepted: 01/04/2023] [Indexed: 01/26/2023] Open
Abstract
Body size is often hypothesized to facilitate or constrain morphological diversity in the cranial, appendicular, and axial skeletons. However, how overall body shape scales with body size (i.e., body shape allometry) and whether these scaling patterns differ between ecological groups remains poorly investigated. Here, we test whether and how the relationships between body shape, body size, and limb lengths differ among species with different locomotor specializations, and describe the underlying morphological components that contribute to body shape evolution among squirrel (Sciuridae) ecotypes. We quantified the body size and shape of 87 squirrel species from osteological specimens held at museum collections. Using phylogenetic comparative methods, we first found that body shape and its underlying morphological components scale allometrically with body size, but these allometric patterns differ among squirrel ecotypes: chipmunks and gliding squirrels exhibited more elongate bodies with increasing body sizes whereas ground squirrels exhibited more robust bodies with increasing body size. Second, we found that only ground squirrels exhibit a relationship between forelimb length and body shape, where more elongate species exhibit relatively shorter forelimbs. Third, we found that the relative length of the ribs and elongation or shortening of the thoracic region contributes the most to body shape evolution across squirrels. Overall, our work contributes to the growing understanding of mammalian body shape evolution and how it is influenced by body size and locomotor ecology, in this case from robust subterranean to gracile gliding squirrels.
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Affiliation(s)
- Tate J. Linden
- University of Washington, Seattle, WA, United States of America
| | | | | | - Annika McFeely
- University of Washington, Seattle, WA, United States of America
| | | | - Chris J. Law
- University of Washington, Seattle, WA, United States of America,University of Texas at Austin, Austin, TX, United States of America,American Museum of Natural History, New York, NY, United States of America
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3
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Porter ME, Hernandez AV, Gervais CR, Rummer JL. Aquatic Walking and Swimming Kinematics of Neonate and Juvenile Epaulette Sharks. Integr Comp Biol 2022; 62:1710-1724. [PMID: 35896482 DOI: 10.1093/icb/icac127] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2022] [Revised: 06/28/2022] [Accepted: 07/06/2022] [Indexed: 01/05/2023] Open
Abstract
The epaulette shark, Hemiscyllium ocellatum, is a small, reef-dwelling, benthic shark that-using its paired fins-can walk, both in and out of water. Within the reef flats, this species experiences short periods of elevated CO2 and hypoxia as well as fluctuating temperatures as reef flats become isolated with the outgoing tide. Past studies have shown that this species is robust (i.e., respiratory and metabolic performance, behavior) to climate change-relevant elevated CO2 levels as well as hypoxia and anoxia tolerant. However, epaulette shark embryos reared under ocean warming conditions hatch earlier and smaller, with altered patterns and coloration, and with higher metabolic costs than their current-day counterparts. Findings to date suggest that this species has adaptations to tolerate some, but perhaps not all, of the challenging conditions predicted for the 21st century. As such, the epaulette shark is emerging as a model system to understand vertebrate physiology in changing oceans. Yet, few studies have investigated the kinematics of walking and swimming, which may be vital to their biological fitness, considering their habitat and propensity for challenging environmental conditions. Given that neonates retain embryonic nutrition via an internalized yolk sac, resulting in a bulbous abdomen, while juveniles actively forage for worms, crustaceans, and small fishes, we hypothesized that difference in body shape over early ontogeny would affect locomotor performance. To test this, we examined neonate and juvenile locomotor kinematics during the three aquatic gaits they utilize-slow-to-medium walking, fast walking, and swimming-using 13 anatomical landmarks along the fins, girdles, and body midline. We found that differences in body shape did not alter kinematics between neonates and juveniles. Overall velocity, fin rotation, axial bending, and tail beat frequency and amplitude were consistent between early life stages. Data suggest that the locomotor kinematics are maintained between neonate and juvenile epaulette sharks, even as their feeding strategy changes. Studying epaulette shark locomotion allows us to understand this-and perhaps related-species' ability to move within and away from challenging conditions in their habitats. Such locomotor traits may not only be key to survival, in general, as a small, benthic mesopredator (i.e., movements required to maneuver into small reef crevices to avoid aerial and aquatic predators), but also be related to their sustained physiological performance under challenging environmental conditions, including those associated with climate change-a topic worthy of future investigation.
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Affiliation(s)
- Marianne E Porter
- Department of Biological Sciences, Florida Atlantic University, 777 Glades Road, Boca Raton, FL 33431, USA
| | - Andrea V Hernandez
- Department of Biological Sciences, Florida Atlantic University, 777 Glades Road, Boca Raton, FL 33431, USA
| | - Connor R Gervais
- ARC Centre of Excellence for Coral Reef Studies, James Cook University, Townsville, QLD 4811, Australia.,Department of Biological Sciences, Macquarie University, Sydney, NSW 2109, Australia
| | - Jodie L Rummer
- ARC Centre of Excellence for Coral Reef Studies, James Cook University, Townsville, QLD 4811, Australia.,College of Science and Engineering, James Cook University, Townsville, QLD 4811, Australia
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KUZNETSOV AN. How big can a walking fish be? A theoretical inference based on observations on four land-dwelling fish genera of South Vietnam. Integr Zool 2022; 17:849-878. [PMID: 34599557 PMCID: PMC9786276 DOI: 10.1111/1749-4877.12599] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Comparative study of terrestrial locomotion of 4 fish genera including Anabas, Channa, Clarias, and Monopterus, was performed in experimental setting with the substrate surface of wet clay. No special adaptations for terrestrial locomotion were found. Every fish uses for propulsion on land what it already has. Eel-shaped Monopterus crawls by body undulations in a serpentine or sidewinding technique, the latter of which was not previously observed beyond snakes. The other 3 fish genera walk by body oscillations using stiff appendages as propulsors. When they are located anteriorly, as the serrate operculum in Anabas and the preaxial spine of the pectoral fin in Clarias, the propulsion is termed prolocomotor, when posteriorly, as the spiny anal fin in Channa-metalocomotor. Channa is the heaviest fish walking out of water in our days, quite comparable in size with first Devonian tetrapods Acanthostega and Tulerpeton. A theoretical calculation is suggested for the upper size limit of a fish capable of terrestrial walking without special locomotor adaptations. It should be roughly 20 cm in the vertical dimension of the trunk, which is just a little above the known size of Devonian tetrapodomorph fishes Panderichthys and Elpistostege. The metalocomotor walking technique of Channa is suggested as the closest extant model for terrestrial locomotion at the fish-tetrapod transition. The major difference is that the metalocomotor propulsor in Channa is represented by the anal fin, while in tetrapodomorphs by the pelvic fins. The sprawled pelvic fins were advantageous in respect of reduced requirement for side-to-side tail swinging.
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Abstract
AbstractMorphological diversity is often attributed as adaptations to distinct ecologies. Although biologists have long hypothesized that distinct ecologies drive the evolution of body shape, these relationships are rarely tested across macroevolutionary scales in mammals. Here, I tested hypotheses that locomotor, hunting, and dietary ecologies influenced body shape evolution in carnivorans, a morphologically and ecologically diverse clade of mammals. I found that adaptive models with ecological trait regimes were poor predictors of carnivoran body shape and the underlying morphological components that contribute to body shape variation. Instead, the best-supported model exhibited clade-based evolutionary shifts, indicating that the complexity and variation of body shape landscape cannot be effectively captured by a priori ecological regimes. However, ecological adaptations of body shapes cannot be ruled out, as aquatic and terrestrial carnivorans exhibited opposite allometric patterns of body shape that may be driven by different gravitational constraints associated with these different environments. Similar to body size, body shape is a prominent feature of vertebrate morphology that may transcend one-to-one mapping relationships between morphology and ecological traits, enabling species with distinct body shapes to exploit similar resources and exhibit similar ecologies. Together, these results demonstrate that the multidimensionality of both body shape morphology and ecology makes it difficult to disentangle the complex relationship among morphological evolution, ecological diversity, and phylogeny across macroevolutionary scales.
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Mehta RS, Donohoe KR. Snowflake morays, Echidna nebulosa, exhibit similar feeding kinematics in terrestrial and aquatic treatments. J Exp Biol 2021; 224:269098. [PMID: 34109983 PMCID: PMC8214832 DOI: 10.1242/jeb.234047] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2020] [Accepted: 04/28/2021] [Indexed: 11/23/2022]
Abstract
Some species of durophagous moray eels (Muraenidae) have been documented emerging from the marine environment to capture intertidal crabs but how they consume prey out of water is unknown. Here, we trained snowflake morays, Echidna nebulosa, to undulate out of the aquatic environment to feed on land. On land, snowflake morays remove prey from the substrate by biting and swallow prey using pharyngeal jaw enabled transport. Although snowflake morays exhibit smaller jaw rotation angles on land when apprehending their prey, transport kinematics involving dorsoventral flexion of the head to protract the pharyngeal jaws and overall feeding times did not differ between terrestrial and aquatic treatments. We suggest that their elongate body plan, ability to rotate their heads in the dorsoventral and lateral directions, and extreme pharyngeal movements all contribute to the ability of durophagous morays to feed in the terrestrial environment. Summary: Body elongation and pharyngeal transport facilitates prey capture and swallowing on land for the snowflake moray, Echidna nebulosa.
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Affiliation(s)
- Rita S Mehta
- Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, CA95064, USA
| | - Kyle R Donohoe
- Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, CA95064, USA
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Friedman ST, Price SA, Corn KA, Larouche O, Martinez CM, Wainwright PC. Body shape diversification along the benthic-pelagic axis in marine fishes. Proc Biol Sci 2020; 287:20201053. [PMID: 32693721 PMCID: PMC7423681 DOI: 10.1098/rspb.2020.1053] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Accepted: 06/27/2020] [Indexed: 12/18/2022] Open
Abstract
Colonization of novel habitats can result in marked phenotypic responses to the new environment that include changes in body shape and opportunities for further morphological diversification. Fishes have repeatedly transitioned along the benthic-pelagic axis, with varying degrees of association with the substrate. Previous work focusing on individual lineages shows that these transitions are accompanied by highly predictable changes in body form. Here, we generalize expectations drawn from this literature to study the effects of habitat on body shape diversification across 3344 marine teleost fishes. We compare rates and patterns of evolution in eight linear measurements of body shape among fishes that live in pelagic, demersal and benthic habitats. While average body shape differs between habitats, these differences are subtle compared with the high diversity of shapes found within each habitat. Benthic living increases the rate of body shape evolution and has led to numerous lineages evolving extreme body shapes, including both exceptionally wide bodies and highly elongate, eel-like forms. By contrast, we find that benthic living is associated with the slowest diversification of structures associated with feeding. Though we find that habitat can serve as an impetus for predictable trait changes, we also highlight the diversity of responses in marine teleosts to opportunities presented by major habitats.
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Affiliation(s)
- S. T. Friedman
- Department of Evolution and Ecology, University of California Davis, Davis, CA 95616, USA
| | - S. A. Price
- Department of Biological Sciences, Clemson University, Clemson, SC 29634, USA
| | - K. A. Corn
- Department of Evolution and Ecology, University of California Davis, Davis, CA 95616, USA
| | - O. Larouche
- Department of Biological Sciences, Clemson University, Clemson, SC 29634, USA
| | - C. M. Martinez
- Department of Evolution and Ecology, University of California Davis, Davis, CA 95616, USA
| | - P. C. Wainwright
- Department of Evolution and Ecology, University of California Davis, Davis, CA 95616, USA
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Redmann E, Sheikh A, Alqahtani A, McCarty-Glenn M, Syed S, Mehta RS, Ward AB. Terrestrial Locomotion in American Eels (Anguilla rostrata): How Substrate and Incline Affect Movement Patterns. Integr Comp Biol 2020; 60:180-189. [PMID: 32251499 DOI: 10.1093/icb/icaa016] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Fishes overcome a variety of challenges in order to invade the terrestrial environment. Terrestrial invasions by fish occur over a variety of environmental contexts. In order to advance their bodies on land, fishes capable of terrestrial excursions tend to use one of three different types of locomotor modes: axial-based, appendage-based, or axial-appendage-based. Elongate species with reduced appendages, such as the American eel, Anguilla rostrata, rely on axial based locomotion in water and on land. When eels move from water to land as part of their complex life cycle, they inevitably encounter a variety of substrates and must traverse variable degrees of incline. The aim of this study was to determine the effect of substrate and incline on the terrestrial locomotion of the American eel. In order to do this, eels were filmed from a dorsal view on three substrates and four inclines: sand, loose pebbles, and fixed (glued) pebbles at 0°, 5°, 10°, and 15°. We digitized 20 evenly spaced points along the body to examine the following characteristics of locomotion: velocity, distance ratio (DR), and wave parameters such as wave amplitude, frequency, and length and assessed whether substrate, incline, or body position affected these parameters. DR, our metric of movement efficiency, was highest on the flat sand condition and lowest on 15° pebble conditions. Efficiency also varied across the body. Velocity followed a similar pattern being highest on sand at 0° and lowest at the steepest inclines. Wave amplitude generally increased toward the tail but was similar across substrates and inclines. Wave frequency was relatively consistent across the body on both pebble substrates, but on sand, frequency was higher toward the head but decreased toward the tail. Wavelengths on sand were the longest at 0° near the head and shorter wavelengths were observed on steeper inclines. Both pebble substrates elicited lower wavelengths that were more similar across the body. Overall, A. rostrata were more effective in navigating compliant substrates but struggled at steeper inclines. Our findings provide insight into locomotor challenges that American eels may encounter as they move from and between bodies of water.
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Affiliation(s)
- Erica Redmann
- Biology Department, Adelphi University, Garden City, NY 11530, USA
| | - Alina Sheikh
- Biology Department, Adelphi University, Garden City, NY 11530, USA
| | - Areej Alqahtani
- Biology Department, Adelphi University, Garden City, NY 11530, USA
| | | | - Shazrah Syed
- Biology Department, Adelphi University, Garden City, NY 11530, USA
| | - Rita S Mehta
- Ecology and Evolutionary Biology, University of California Santa Cruz, Santa Cruz, CA 95060, USA
| | - Andrea B Ward
- Biology Department, Adelphi University, Garden City, NY 11530, USA
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9
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Mehta RS, Akesson K, Redmann E, McCarty‐Glenn M, Ortega R, Syed S, Yap‐Chiongco M, Jacquemetton C, Ward AB. Terrestrial locomotion in elongate fishes: exploring the roles of morphology and substrate in facilitating locomotion. J Zool (1987) 2020. [DOI: 10.1111/jzo.12794] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Affiliation(s)
- R. S. Mehta
- Department of Ecology and Evolutionary Biology University of California Santa Cruz Santa Cruz CA USA
| | - K. Akesson
- Department of Ecology and Evolutionary Biology University of California Santa Cruz Santa Cruz CA USA
| | - E. Redmann
- Department of Biology Adelphi University Garden City NY USA
| | | | - R. Ortega
- Department of Biology Adelphi University Garden City NY USA
| | - S. Syed
- Department of Biology Adelphi University Garden City NY USA
| | - M. Yap‐Chiongco
- Department of Ecology and Evolutionary Biology University of California Santa Cruz Santa Cruz CA USA
- Department of Biological Sciences University of Alabama Tuscaloosa AL USA
| | - C. Jacquemetton
- Department of Ecology and Evolutionary Biology University of California Santa Cruz Santa Cruz CA USA
- Department of Ecology and Evolutionary Biology University of California Los Angeles Los Angeles CA USA
| | - A. B. Ward
- Department of Biology Adelphi University Garden City NY USA
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10
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Bergmann PJ, Mann SDW, Morinaga G, Freitas ES, Siler CD. Convergent Evolution of Elongate Forms in Craniates and of Locomotion in Elongate Squamate Reptiles. Integr Comp Biol 2020; 60:190-201. [DOI: 10.1093/icb/icaa015] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Abstract
Synopsis Elongate, snake- or eel-like, body forms have evolved convergently many times in most major lineages of vertebrates. Despite studies of various clades with elongate species, we still lack an understanding of their evolutionary dynamics and distribution on the vertebrate tree of life. We also do not know whether this convergence in body form coincides with convergence at other biological levels. Here, we present the first craniate-wide analysis of how many times elongate body forms have evolved, as well as rates of its evolution and reversion to a non-elongate form. We then focus on five convergently elongate squamate species and test if they converged in vertebral number and shape, as well as their locomotor performance and kinematics. We compared each elongate species to closely related quadrupedal species and determined whether the direction of vertebral or locomotor change matched in each case. The five lineages examined are obscure species from remote locations, providing a valuable glimpse into their biology. They are the skink lizards Brachymeles lukbani, Lerista praepedita, and Isopachys anguinoides, the basal squamate Dibamus novaeguineae, and the basal snake Malayotyphlops cf. ruficaudus. Our results support convergence among these species in the number of trunk and caudal vertebrae, but not vertebral shape. We also find that the elongate species are relatively slower than their limbed counterparts and move with lower frequency and higher amplitude body undulations, with the exception of Isopachys. This is among the first evidence of locomotor convergence across distantly related, elongate species.
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Affiliation(s)
| | - Sara D W Mann
- Department of Biology, Clark University, Worcester, MA, USA
| | - Gen Morinaga
- Department of Biology, Clark University, Worcester, MA, USA
- Department of Integrative Biology, Oklahoma State University, Stillwater, OK, USA
| | - Elyse S Freitas
- Department of Biology and Sam Noble Oklahoma Museum of Natural History, University of Oklahoma, Norman, OK, USA
| | - Cameron D Siler
- Department of Biology and Sam Noble Oklahoma Museum of Natural History, University of Oklahoma, Norman, OK, USA
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Morinaga G, Bergmann PJ. Evolution of fossorial locomotion in the transition from tetrapod to snake-like in lizards. Proc Biol Sci 2020; 287:20200192. [PMID: 32183623 DOI: 10.1098/rspb.2020.0192] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Dramatic evolutionary transitions in morphology are often assumed to be adaptive in a new habitat. However, these assumptions are rarely tested because such tests require intermediate forms, which are often extinct. In vertebrates, the evolution of an elongate, limbless body is generally hypothesized to facilitate locomotion in fossorial and/or cluttered habitats. However, these hypotheses remain untested because few studies examine the locomotion of species ranging in body form from tetrapod to snake-like. Here, we address these functional hypotheses by testing whether trade-offs exist between locomotion in surface, fossorial and cluttered habitats in Australian Lerista lizards, which include multiple intermediate forms. We found that snake-like species penetrated sand substrates faster than more lizard-like species, representing the first direct support of the adaptation to fossoriality hypothesis. By contrast, body form did not affect surface locomotion or locomotion through cluttered leaf litter. Furthermore, all species with hindlimbs used them during both fossorial and surface locomotion. We found no evidence of a trade-off between fossorial and surface locomotion. This may be either because Lerista employed kinematic strategies that took advantage of both axial- and limb-based propulsion. This may have led to the differential occupation of their habitat, facilitating diversification of intermediate forms.
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Affiliation(s)
- Gen Morinaga
- Department of Biology, Clark University, Worcester, MA 01610, USA
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12
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Morinaga G, Bergmann PJ. Angles and waves: intervertebral joint angles and axial kinematics of limbed lizards, limbless lizards, and snakes. ZOOLOGY 2019; 134:16-26. [PMID: 31146904 DOI: 10.1016/j.zool.2019.04.003] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2018] [Revised: 04/04/2019] [Accepted: 04/05/2019] [Indexed: 11/15/2022]
Abstract
Segmentation gives rise to the anterior-posterior axis in many animals, and in vertebrates this axis comprises serially arranged vertebrae. Modifications to the vertebral column abound, and a recurring, but functionally understudied, change is the elongation of the body through the addition and/or elongation of vertebrae. Here, we compared the vertebral and axial kinematics of the robustly limbed Fire skink (Riopa fernandi) representing the ancestral form, the limbless European glass lizard (Ophisaurus apodus), and the Northern water snake (Nerodia sipedon). We induced these animals to traverse through channels and peg arrays of varied widths and densities, respectively, using high-speed X-ray and light video. We found that even though the snake had substantially more and shorter vertebrae than either lizard, intervertebral joint angles did not differ between species in most treatment levels. All three species decreased the amplitude and wavelength of their undulations as channels narrowed and the lizard species increased wave frequency in narrower channels. In peg arrays, both lizard species decreased wave amplitude, while the snake showed no differences. All three species maintained similar wavelengths and frequencies as peg density increased in most cases. Our results suggest that amplitude is decoupled from wavelength and frequency in all three focal taxa. The combination of musculoskeletal differences and the decoupling of axial kinematic traits likely facilitates the formation of different undulatory waves, thereby allowing limbless species to adopt different modes of locomotion.
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Affiliation(s)
- Gen Morinaga
- Department of Biology, Clark University, 950 Main Street, Worcester, Massachusetts 01610, USA.
| | - Philip J Bergmann
- Department of Biology, Clark University, 950 Main Street, Worcester, Massachusetts 01610, USA
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13
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Tingle JL, Gartner GEA, Jayne BC, Garland T. Ecological and phylogenetic variability in the spinalis muscle of snakes. J Evol Biol 2017; 30:2031-2043. [PMID: 28857331 DOI: 10.1111/jeb.13173] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2017] [Revised: 08/03/2017] [Accepted: 08/18/2017] [Indexed: 02/06/2023]
Abstract
Understanding the origin and maintenance of functionally important subordinate traits is a major goal of evolutionary physiologists and ecomorphologists. Within the confines of a limbless body plan, snakes are diverse in terms of body size and ecology, but we know little about the functional traits that underlie this diversity. We used a phylogenetically diverse group of 131 snake species to examine associations between habitat use, sidewinding locomotion and constriction behaviour with the number of body vertebrae spanned by a single segment of the spinalis muscle, with total numbers of body vertebrae used as a covariate in statistical analyses. We compared models with combinations of these predictors to determine which best fit the data among all species and for the advanced snakes only (N = 114). We used both ordinary least-squares models and phylogenetic models in which the residuals were modelled as evolving by the Ornstein-Uhlenbeck process. Snakes with greater numbers of vertebrae tended to have spinalis muscles that spanned more vertebrae. Habitat effects dominated models for analyses of all species and advanced snakes only, with the spinalis length spanning more vertebrae in arboreal species and fewer vertebrae in aquatic and burrowing species. Sidewinding specialists had shorter muscle lengths than nonspecialists. The relationship between prey constriction and spinalis length was less clear. Differences among clades were also strong when considering all species, but not for advanced snakes alone. Overall, these results suggest that muscle morphology may have played a key role in the adaptive radiation of snakes.
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Affiliation(s)
- J L Tingle
- Department of Evolution, Ecology, and Organismal Biology, University of California, Riverside, CA, USA
| | - G E A Gartner
- Department of Evolution, Ecology, and Organismal Biology, University of California, Riverside, CA, USA
| | - B C Jayne
- Department of Biological Sciences, ML006, University of Cincinnati, Cincinnati, OH, USA
| | - T Garland
- Department of Evolution, Ecology, and Organismal Biology, University of California, Riverside, CA, USA
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14
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Locomotor flexibility of Polypterus senegalus across various aquatic and terrestrial substrates. ZOOLOGY 2016; 119:447-454. [DOI: 10.1016/j.zool.2016.05.001] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2015] [Revised: 02/23/2016] [Accepted: 05/02/2016] [Indexed: 01/25/2023]
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