1
|
Bertozzo F, Stein K, Varotto E, Galassi FM, Ruffell A, Murphy E. Histological analysis and etiology of a pathological iguanodontian femur from England. J Anat 2024; 245:490-500. [PMID: 38726991 PMCID: PMC11306762 DOI: 10.1111/joa.14053] [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: 01/12/2023] [Revised: 04/15/2024] [Accepted: 04/15/2024] [Indexed: 08/09/2024] Open
Abstract
Derived ornithopods, such as hadrosaurids, show a high occurrence of fossilized lesions and diseases. However, paleopathologies in iguanodontians seem to be less common, considering the rich fossil record of these taxa in Europe, in particular in Belgium, Britain and Spain. Here, we describe an iguanodontian femur discovered in England that exhibits a large overgrowth of its lateral aspect, not previously recognized in any other similar remains. The specimen was scanned with micro-computed tomography (microCT) and later sectioned in three sites of the overgrowth for histological analysis. The femur belongs to an early adult Iguanodontia indet., based on the presence of a woven parallel fibered complex in the outer cortex and three to four lines of arrested growth. Internal analysis of the dome-like overgrowth suggests it can be diagnosed as a fracture callus. The injury might have negatively impacted upon the animal's locomotion as the trauma had occurred in the region above the knee, a crucial spot for hindlimb musculature. Finally, a cancellous medullary bone-like tissue was recognized in the medullary cavity next to the pathological overgrowth. An attempt was made to determine the precise nature of this tissue, as medullary bone is linked with the ovulation period in (avian) dinosaurs, whereas other types of endosteal, medullary bone-like tissue have previously been recognized in pathological bones.
Collapse
Affiliation(s)
- Filippo Bertozzo
- Operational Directorate Earth and History of Life, Royal Belgian Institute of Natural Sciences, Brussels, Belgium
- Sociedade de Historia Natural, Torres Vedras, Portugal
| | - Koen Stein
- Vrije Universiteit Brussel, Brussels, Belgium
| | - Elena Varotto
- Archaeology, College of Humanities, Arts and Social Sciences, Flinders University, Adelaide, South Australia, Australia
- FAPAB Research Center, Avola (SR), Sicily, Italy
| | - Francesco M Galassi
- Department of Anthropology, Faculty of Biology and Environmental Protection, University of Lodz, Lodz, Poland
| | - Alastair Ruffell
- School of Natural and Built Environment, Queen's University Belfast, Belfast, Northern Ireland, UK
| | - Eileen Murphy
- School of Natural and Built Environment, Queen's University Belfast, Belfast, Northern Ireland, UK
| |
Collapse
|
2
|
Griffin BW, Martin-Silverstone E, Pêgas RV, Meilak EA, Costa FR, Palmer C, Rayfield EJ. Modelling take-off moment arms in an ornithocheiraean pterosaur. PeerJ 2024; 12:e17678. [PMID: 39119105 PMCID: PMC11308997 DOI: 10.7717/peerj.17678] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2023] [Accepted: 06/12/2024] [Indexed: 08/10/2024] Open
Abstract
Take-off is a vital part of powered flight which likely constrains the size of birds, yet extinct pterosaurs are known to have reached far larger sizes. Three different hypothesised take-off motions (bipedal burst launching, bipedal countermotion launching, and quadrupedal launching) have been proposed as explanations for how pterosaurs became airborne and circumvented this proposed morphological limit. We have constructed a computational musculoskeletal model of a 5 m wingspan ornithocheiraean pterosaur, reconstructing thirty-four key muscles to estimate the muscle moment arms throughout the three hypothesised take-off motions. Range of motion constrained hypothetical kinematic sequences for bipedal and quadrupedal take-off motions were modelled after extant flying vertebrates. Across our simulations we did not find higher hindlimb moment arms for bipedal take-off motions or noticeably higher forelimb moment arms in the forelimb for quadrupedal take-off motions. Despite this, in all our models we found the muscles utilised in the quadrupedal take-off have the largest total launch applicable moment arms throughout the entire take-off sequences and for the take-off pose. This indicates the potential availability of higher leverage for a quadrupedal take-off than hypothesised bipedal motions in pterosaurs pending further examination of muscle forces.
Collapse
Affiliation(s)
- Benjamin W. Griffin
- Palaeobiology Group, School of Earth Sciences, University of Bristol, Bristol, United Kingdom
- School of Biological and Environmental Sciences, Liverpool John Moores University, Liverpool, United Kingdom
| | | | - Rodrigo V. Pêgas
- Laboratory of Vertebrate Paleontology and Animal Behavior. Federal University of ABC, Alameda da Universidade, São Bernardo do Campo, SP, Brazil
| | - Erik Anthony Meilak
- School of Pharmacy and Bioengineering, University of Keele, Keele, United Kingdom
| | - Fabiana R. Costa
- Laboratory of Vertebrate Paleontology and Animal Behavior. Federal University of ABC, Alameda da Universidade, São Bernardo do Campo, SP, Brazil
| | - Colin Palmer
- Palaeobiology Group, School of Earth Sciences, University of Bristol, Bristol, United Kingdom
| | - Emily J. Rayfield
- Palaeobiology Group, School of Earth Sciences, University of Bristol, Bristol, United Kingdom
| |
Collapse
|
3
|
Lacerda MBS, Bittencourt JS, Hutchinson JR. Reconstruction of the pelvic girdle and hindlimb musculature of the early tetanurans Piatnitzkysauridae (Theropoda, Megalosauroidea). J Anat 2024; 244:557-593. [PMID: 38037880 PMCID: PMC10941590 DOI: 10.1111/joa.13983] [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: 06/15/2023] [Revised: 11/10/2023] [Accepted: 11/15/2023] [Indexed: 12/02/2023] Open
Abstract
Piatnitzkysauridae were Jurassic theropods that represented the earliest diverging branch of Megalosauroidea, being one of the earliest lineages to have evolved moderate body size. This clade's typical body size and some unusual anatomical features raise questions about locomotor function and specializations to aid in body support; and other palaeobiological issues. Biomechanical models and simulations can illuminate how extinct animals may have moved, but require anatomical data as inputs. With a phylogenetic context, osteological evidence, and neontological data on anatomy, it is possible to infer the musculature of extinct taxa. Here, we reconstructed the hindlimb musculature of Piatnitzkysauridae (Condorraptor, Marshosaurus, and Piatnitzkysaurus). We chose this clade for future usage in biomechanics, for comparisons with myological reconstructions of other theropods, and for the resulting evolutionary implications of our reconstructions; differential preservation affects these inferences, so we discuss these issues as well. We considered 32 muscles in total: for Piatnitzkysaurus, the attachments of 29 muscles could be inferred based on the osteological correlates; meanwhile, in Condorraptor and Marshosaurus, we respectively inferred 21 and 12 muscles. We found great anatomical similarity within Piatnitzkysauridae, but differences such as the origin of M. ambiens and size of M. caudofemoralis brevis are present. Similarities were evident with Aves, such as the division of the M. iliofemoralis externus and M. iliotrochantericus caudalis and a broad depression for the M. gastrocnemius pars medialis origin on the cnemial crest. Nevertheless, we infer plesiomorphic features such as the origins of M. puboischiofemoralis internus 1 around the "cuppedicus" fossa and M. ischiotrochantericus medially on the ischium. As the first attempt to reconstruct muscles in early tetanurans, our study allows a more complete understanding of myological evolution in theropod pelvic appendages.
Collapse
Affiliation(s)
- Mauro B. S. Lacerda
- Structure and Motion Laboratory, Department of Comparative Biomedical SciencesThe Royal Veterinary CollegeHatfieldUK
- Pós‐Graduação em ZoologiaInstituto de Ciências Biológicas, Universidade Federal de Minas GeraisBelo HorizonteBrazil
| | - Jonathas S. Bittencourt
- Departamento de GeologiaInstituto de Geociências, Universidade Federal de Minas GeraisBelo HorizonteBrazil
| | - John R. Hutchinson
- Structure and Motion Laboratory, Department of Comparative Biomedical SciencesThe Royal Veterinary CollegeHatfieldUK
| |
Collapse
|
4
|
Hedrick BP. Dots on a screen: The past, present, and future of morphometrics in the study of nonavian dinosaurs. Anat Rec (Hoboken) 2023. [PMID: 36922704 DOI: 10.1002/ar.25183] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2022] [Revised: 10/28/2022] [Accepted: 02/12/2023] [Indexed: 03/18/2023]
Abstract
Using morphometrics to study nonavian dinosaur fossils is a practice that predates the origin of the word "dinosaur." By the 1970s, linear morphometrics had become established as a valuable tool for analyzing intra- and interspecific variation in nonavian dinosaurs. With the advent of more recent techniques such as geometric morphometrics and more advanced statistical approaches, morphometric analyses of nonavian dinosaurs have proliferated, granting unprecedented insight into many aspects of their biology and evolution. I outline the past, present, and future of morphometrics as applied to the study of nonavian dinosaurs zeroing in on five aspects of nonavian dinosaur paleobiology where morphometrics has been widely utilized to advance our knowledge: systematics, sexual dimorphism, locomotion, macroevolution, and trackways. Morphometric methods are especially susceptible to taphonomic distortion. As such, the impact of taphonomic distortion on original fossil shape is discussed as are current and future methods for quantifying and accounting for distortion with the goal of reducing the taphonomic noise to biological signal ratio. Finally, the future of morphometrics in nonavian dinosaur paleobiology is discussed as paleobiologists move into a "virtual paleobiology" framework, whereby digital renditions of fossils are captured via methods such as photogrammetry and computed tomography. These primary data form the basis for three-dimensional (3D) geometric morphometric analyses along with a slew of other forms of analyses. These 3D specimen data form part of the extended specimen and help to democratize paleobiology, unlocking the specimen from the physical museum and making the specimen available to researchers across the world.
Collapse
Affiliation(s)
- Brandon P Hedrick
- Department of Biomedical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, New York, USA
| |
Collapse
|
5
|
Dempsey M, Maidment SCR, Hedrick BP, Bates KT. Convergent evolution of quadrupedality in ornithischian dinosaurs was achieved through disparate forelimb muscle mechanics. Proc Biol Sci 2023; 290:20222435. [PMID: 36722082 PMCID: PMC9890092 DOI: 10.1098/rspb.2022.2435] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2022] [Accepted: 01/09/2023] [Indexed: 02/02/2023] Open
Abstract
The secondary evolution of quadrupedality from bipedal ancestry is a rare evolutionary transition in tetrapods yet occurred convergently at least three times within ornithischian dinosaurs. Despite convergently evolving quadrupedal gait, ornithischians exhibited variable anatomy, particularly in the forelimbs, which underwent a major functional change from assisting in foraging and feeding in bipeds to becoming principal weight-bearing components of the locomotor system in quadrupeds. Here, we use three-dimensional multi-body dynamics models to demonstrate quantitatively that different quadrupedal ornithischian clades evolved distinct forelimb musculature, particularly around the shoulder. We find that major differences in glenohumeral abduction-adduction and long axis rotation muscle leverages were key drivers of mechanical disparity, thereby refuting previous hypotheses about functional convergence in major clades. Elbow muscle leverages were also disparate across the major ornithischian lineages, although high elbow extension muscle leverages were convergent between most quadrupeds. Unlike in ornithischian hind limbs, where differences are more closely tied to functional similarity than phylogenetic relatedness, mechanical disparity in ornithischian forelimbs appears to have been shaped primarily by phylogenetic constraints. Differences in ancestral bipedal taxa within each clade may have resulted in disparate ecomorphological constraints on the evolutionary pathways driving divergence in their quadrupedal descendants.
Collapse
Affiliation(s)
- Matthew Dempsey
- Department of Musculoskeletal & Ageing Science, Institute of Life Course & Medical Sciences, University of Liverpool, The William Henry Duncan Building, 6 West Derby Street, Liverpool L7 8TX, UK
- Department of Earth Sciences, The Natural History Museum, Cromwell Road, London SW7 5BD, UK
| | | | - Brandon P. Hedrick
- Department of Biomedical Sciences, College of Veterinary Medicine, Cornell University, 930 Campus Road, Ithaca, NY 14853, USA
| | - Karl T. Bates
- Department of Musculoskeletal & Ageing Science, Institute of Life Course & Medical Sciences, University of Liverpool, The William Henry Duncan Building, 6 West Derby Street, Liverpool L7 8TX, UK
| |
Collapse
|
6
|
Norman DB, Baron MG, Garcia MS, Müller RT. Taxonomic, palaeobiological and evolutionary implications of a phylogenetic hypothesis for Ornithischia (Archosauria: Dinosauria). Zool J Linn Soc 2022. [DOI: 10.1093/zoolinnean/zlac062] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
Abstract
The origin and evolutionary relationships of ornithischian dinosaurs are topics that have undergone a series of substantial revisions. At present there are several competing hypotheses concerning the relationship between Ornithischia and the other principal clades of Dinosauria. Some hypotheses have posited a tree topology within Dinosauria that imply a ‘ghost-lineage’ for Ornithischia (whose representatives make their first unambiguous appearance in the Hettangian) that extends through a substantial portion of Triassic time. In contrast, other hypotheses have placed conventionally Triassic dinosauromorph (stem-lineage Dinosauria) taxa within the clade Ornithischia. Recently, a large-scale phylogenetic analysis recovered an array of taxa, known as ‘silesaurids’, as a paraphyletic assemblage of taxa (referred to in this article using the informal terms silesaurs or silesaurians) on the branch leading to the clade Ornithischia. This latter hypothesis of relationships would account for the apparent absence of Triassic ornithischians, because stem-lineage ornithischians (silesaurs in this article) are exclusively Triassic. However, the analysis that produced this novel topology used a dataset that, in its original form, did not include all early representatives of Ornithischia (sensu lato), and did not incorporate all the anatomical characters that have been suggested to unite Ornithischia with other dinosaurian clades (Theropoda and Sauropodomorpha). Nor did the initial study go on to expand upon some important taxonomic, palaeobiological and evolutionary implications of a topology that links a paraphyletic array of silesaurs to the clade Ornithischia. The present article addresses these latter issues by expansion and re-analysis of the original dataset. The results find further support for the hypothesis that silesaurs comprise a paraphyletic grouping of taxa on the stem of Ornithischia and that successive silesaur taxa acquire anatomical characters anagenetically in a process that culminates in the assembly of what may be described as a ‘traditional’ ornithischian. The overall topology of the consensus tree remains but little changed from the original analysis, despite the addition of new taxa and characters. To provide stability to this area of the tree and to preserve the most important of the relevant taxonomic names, we suggest a revised taxonomic framework for ornithischians that is consistent with this new topology. We retain the name Ornithischia for the total-group (traditional Ornithischia and its stem-lineage), while we resuscitate a name originally proposed by Richard Owen, Prionodontia (= ‘coarse edged teeth’) for the clade containing only the so-called traditional ornithischian (= ‘bird-hipped’) dinosaurs. We also erect Parapredentata as a more exclusive subclade in Ornithischia. This novel taxonomic framework is intended to provide phylogenetic clarity and a degree of stability in Ornithischia and Dinosauria as further analyses and new data continue to refine and re-shape the tree. The data presented in this study represent a stage in our attempt to establish an early dinosaur dataset in which character definitions and character scores are agreed upon and used consistently.
Collapse
Affiliation(s)
- David B Norman
- Department of Earth Sciences, University of Cambridge , Downing Street, Cambridge CB2 3EQ , UK
- Christ’s College , St Andrew’s Street, Cambridge CB2 3BU , UK
| | | | - Mauricio S Garcia
- Centro de Apoio à Pesquisa Paleontológica da Quarta Colônia, Universidade Federal de Santa Maria , São João do Polêsine, RS, 598 , Brazil
- Programa de Pós Graduação em Biodiversidade Animal, Universidade Federal de Santa Maria , Santa Maria, RS 97105-900 , Brazil
| | - Rodrigo Temp Müller
- Centro de Apoio à Pesquisa Paleontológica da Quarta Colônia, Universidade Federal de Santa Maria , São João do Polêsine, RS, 598 , Brazil
- Programa de Pós Graduação em Biodiversidade Animal, Universidade Federal de Santa Maria , Santa Maria, RS 97105-900 , Brazil
| |
Collapse
|
7
|
Löffler L, Wölfer J, Gavrilei F, Nyakatura JA. Computational Modeling of Gluteus Medius Muscle Moment Arm in Caviomorph Rodents Reveals Ecomorphological Specializations. Front Bioeng Biotechnol 2022; 10:806314. [PMID: 35694234 PMCID: PMC9174681 DOI: 10.3389/fbioe.2022.806314] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2021] [Accepted: 03/29/2022] [Indexed: 11/13/2022] Open
Abstract
Vertebrate musculoskeletal locomotion is realized through lever-arm systems. The instantaneous muscle moment arm (IMMA), which is expected to be under selective pressure and thus of interest for ecomorphological studies, is a key aspect of these systems. The IMMA changes with joint motion. It’s length change is technically difficult to acquire and has not been compared in a larger phylogenetic ecomorphological framework, yet. Usually, proxies such as osteological in-levers are used instead. We used 18 species of the ecologically diverse clade of caviomorph rodents to test whether its diversity is reflected in the IMMA of the hip extensor M. gluteus medius. A large IMMA is beneficial for torque generation; a small IMMA facilitates fast joint excursion. We expected large IMMAs in scansorial species, small IMMAs in fossorial species, and somewhat intermediate IMMAs in cursorial species, depending on the relative importance of acceleration and joint angular velocity. We modeled the IMMA over the entire range of possible hip extensions and applied macroevolutionary model comparison to selected joint poses. We also obtained the osteological in-lever of the M. gluteus medius to compare it to the IMMA. At little hip extension, the IMMA was largest on average in scansorial species, while the other two lifestyles were similar. We interpret this as an emphasized need for increased hip joint torque when climbing on inclines, especially in a crouched posture. Cursorial species might benefit from fast joint excursion, but their similarity with the fossorial species is difficult to interpret and could hint at ecological similarities. At larger extension angles, cursorial species displayed the second-largest IMMAs after scansorial species. The larger IMMA optimum results in powerful hip extension which coincides with forward acceleration at late stance beneficial for climbing, jumping, and escaping predators. This might be less relevant for a fossorial lifestyle. The results of the in-lever only matched the IMMA results of larger hip extension angles, suggesting that the modeling of the IMMA provides more nuanced insights into adaptations of musculoskeletal lever-arm systems than this osteological proxy.
Collapse
|
8
|
Demuth OE, Wiseman ALA, van Beesel J, Mallison H, Hutchinson JR. Three-dimensional polygonal muscle modelling and line of action estimation in living and extinct taxa. Sci Rep 2022; 12:3358. [PMID: 35233027 PMCID: PMC8888607 DOI: 10.1038/s41598-022-07074-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Accepted: 02/08/2022] [Indexed: 11/24/2022] Open
Abstract
Biomechanical models and simulations of musculoskeletal function rely on accurate muscle parameters, such as muscle masses and lines of action, to estimate force production potential and moment arms. These parameters are often obtained through destructive techniques (i.e., dissection) in living taxa, frequently hindering the measurement of other relevant parameters from a single individual, thus making it necessary to combine multiple specimens and/or sources. Estimating these parameters in extinct taxa is even more challenging as soft tissues are rarely preserved in fossil taxa and the skeletal remains contain relatively little information about the size or exact path of a muscle. Here we describe a new protocol that facilitates the estimation of missing muscle parameters (i.e., muscle volume and path) for extant and extinct taxa. We created three-dimensional volumetric reconstructions for the hindlimb muscles of the extant Nile crocodile and extinct stem-archosaur Euparkeria, and the shoulder muscles of an extant gorilla to demonstrate the broad applicability of this methodology across living and extinct animal clades. Additionally, our method can be combined with surface geometry data digitally captured during dissection, thus facilitating downstream analyses. We evaluated the estimated muscle masses against physical measurements to test their accuracy in estimating missing parameters. Our estimated muscle masses generally compare favourably with segmented iodine-stained muscles and almost all fall within or close to the range of observed muscle masses, thus indicating that our estimates are reliable and the resulting lines of action calculated sufficiently accurately. This method has potential for diverse applications in evolutionary morphology and biomechanics.
Collapse
Affiliation(s)
- Oliver E Demuth
- Structure and Motion Laboratory, Department of Comparative Biomedical Sciences, The Royal Veterinary College, Hatfield, UK.
- Department of Earth Sciences, University of Cambridge, Cambridge, UK.
| | - Ashleigh L A Wiseman
- Structure and Motion Laboratory, Department of Comparative Biomedical Sciences, The Royal Veterinary College, Hatfield, UK
- McDonald Institute for Archaeological Research, University of Cambridge, Cambridge, UK
| | - Julia van Beesel
- Department of Human Evolution, Max-Planck-Institute for Evolutionary Anthropology, Leipzig, Germany
| | - Heinrich Mallison
- Zoological Museum, University of Hamburg, Hamburg, Germany
- Palaeo3D, Rain am Lech, Germany
| | - John R Hutchinson
- Structure and Motion Laboratory, Department of Comparative Biomedical Sciences, The Royal Veterinary College, Hatfield, UK
| |
Collapse
|
9
|
Smith KL, Wang Y, Colloca L. Impact of Virtual Reality Technology on Pain and Anxiety in Pediatric Burn Patients: A Systematic Review and Meta-Analysis. FRONTIERS IN VIRTUAL REALITY 2022; 2:751735. [PMID: 36247202 PMCID: PMC9563984 DOI: 10.3389/frvir.2021.751735] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
INTRODUCTION Virtual reality (VR) has the potential to lessen pain and anxiety experienced by pediatric patients undergoing burn wound care procedures. Population-specific variables require novel technological application and thus, a systematic review among studies on its impact is warranted. OBJECTIVE The objective of this review was to evaluate the effectiveness of VR on pain in children with burn injuries undergoing wound care procedures. METHODS A systematic literature review was performed using PubMed and CINAHL databases from January 2010 to July 2021 with the keywords "pediatric," "burn," "virtual reality," and "pain." We included experimental studies of between- and within-subjects designs in which pediatric patients' exposure to virtual reality technology during burn wound care functioned as the intervention of interest. Two researchers independently performed the literature search, made judgements of inclusion/exclusion based on agreed-upon criteria, abstracted data, and assessed quality of evidence using a standardized appraisal tool. A meta-analysis was conducted to evaluate the effectiveness of the VR on burning procedural pain in pediatric population. Standardized mean difference (SMD) was used as an index of combined effect size, and a random effect model was used for meta-analysis. RESULTS Ten articles published between January 2010 and July 2021 passed the selection criteria: six randomized controlled trials and four randomized repeated-measures studies. Consistent results among the studies provided support for VR as effective in reducing pain and potentially pain related anxiety in children undergoing burn wound care through preprocedural preparation (n = 2) and procedural intervention (n = 8). VR effects on pain intensity ratings were moderate to large (SMD=0.60, 95%CI=0.28-0.93, p=0.0037 with no significant heterogeneity of VR intervention effects between studies. Only one study reported direct influence of VR intervention on pre-procedural situational anxiety with a moderate effect size (Cohen's d = 0.575, 95%CI = 0.11-1.04). CONCLUSION Children's exposure to VR during burn care procedures was associated with lower levels of pain and pain related anxiety. Moderate to large effect sizes support the integration of VR into traditional pediatric burn pain protocols irrespective of innovative delivery methods and content required for use in burned pediatric patients.
Collapse
Affiliation(s)
- Kathryn L. Smith
- Department of Pain and Translational Symptom Science, School of Nursing, University of Maryland, Baltimore, MD, United States
| | - Yang Wang
- Department of Pain and Translational Symptom Science, School of Nursing, University of Maryland, Baltimore, MD, United States
- Center to Advance Chronic Pain Research, University of Maryland, Baltimore, MD, United States
| | - Luana Colloca
- Department of Pain and Translational Symptom Science, School of Nursing, University of Maryland, Baltimore, MD, United States
- Center to Advance Chronic Pain Research, University of Maryland, Baltimore, MD, United States
- Departments of Anesthesiology and Psychiatry, School of Medicine, University of Maryland, Baltimore, MD, United States
- Correspondence: Luana Colloca,
| |
Collapse
|
10
|
Regnault S, Fahn-Lai P, Pierce SE. Validation of an Echidna Forelimb Musculoskeletal Model Using XROMM and diceCT. Front Bioeng Biotechnol 2021; 9:751518. [PMID: 34820362 PMCID: PMC8606742 DOI: 10.3389/fbioe.2021.751518] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2021] [Accepted: 10/04/2021] [Indexed: 11/13/2022] Open
Abstract
In evolutionary biomechanics, musculoskeletal computer models of extant and extinct taxa are often used to estimate joint range of motion (ROM) and muscle moment arms (MMAs), two parameters which form the basis of functional inferences. However, relatively few experimental studies have been performed to validate model outputs. Previously, we built a model of the short-beaked echidna (Tachyglossus aculeatus) forelimb using a traditional modelling workflow, and in this study we evaluate its behaviour and outputs using experimental data. The echidna is an unusual animal representing an edge-case for model validation: it uses a unique form of sprawling locomotion, and possesses a suite of derived anatomical features, in addition to other features reminiscent of extinct early relatives of mammals. Here we use diffusible iodine-based contrast-enhanced computed tomography (diceCT) alongside digital and traditional dissection to evaluate muscle attachments, modelled muscle paths, and the effects of model alterations on the MMA outputs. We use X-ray Reconstruction of Moving Morphology (XROMM) to compare ex vivo joint ROM to model estimates based on osteological limits predicted via single-axis rotation, and to calculate experimental MMAs from implanted muscles using a novel geometric method. We also add additional levels of model detail, in the form of muscle architecture, to evaluate how muscle torque might alter the inferences made from MMAs alone, as is typical in evolutionary studies. Our study identifies several key findings that can be applied to future models. 1) A light-touch approach to model building can generate reasonably accurate muscle paths, and small alterations in attachment site seem to have minimal effects on model output. 2) Simultaneous movement through multiple degrees of freedom, including rotations and translation at joints, are necessary to ensure full joint ROM is captured; however, single-axis ROM can provide a reasonable approximation of mobility depending on the modelling objectives. 3) Our geometric method of calculating MMAs is consistent with model-predicted MMAs calculated via partial velocity, and is a potentially useful tool for others to create and validate musculoskeletal models. 4) Inclusion of muscle architecture data can change some functional inferences, but in many cases reinforced conclusions based on MMA alone.
Collapse
Affiliation(s)
- Sophie Regnault
- Museum of Comparative Zoology and Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, United States
- Institute of Biological, Environment and Rural Sciences, Aberystwyth University, Aberystwyth, United Kingdom
| | - Philip Fahn-Lai
- Museum of Comparative Zoology and Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, United States
- Concord Field Station and Department of Organismic and Evolutionary Biology, Harvard University, Bedford, MA, United States
| | - Stephanie E. Pierce
- Museum of Comparative Zoology and Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, United States
| |
Collapse
|
11
|
Sedlmayr JC, Bates KT, Wisco JJ, Schachner ER. Revision of hip flexor anatomy and function in modern humans, and implications for the evolution of hominin bipedalism. Anat Rec (Hoboken) 2021; 305:1147-1167. [PMID: 34569157 DOI: 10.1002/ar.24769] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2020] [Revised: 08/10/2021] [Accepted: 08/12/2021] [Indexed: 11/08/2022]
Abstract
Hip flexor musculature was instrumental in the evolution of hominin bipedal gait and in endurance running for hunting in the genus Homo. The iliacus and psoas major muscles were historically considered to have separate tendons with different insertions on the lesser trochanter. However, in the early 20th century, it became "common knowledge" that the two muscles insert together on the lesser trochanter as the "iliopsoas" tendon. We revisited the findings of early anatomists and tested the more recent paradigm of a common "iliopsoas" tendon based on dissections of hips and their associated musculature (n = 17). We rediscovered that the tendon of the psoas muscle inserts only into a crest running from the superior to anterior aspect of the lesser trochanter, separate from the iliacus. The iliacus inserts fleshly into the anterior portion of the lesser trochanter and into an inferior crest extending from it. We developed 3D multibody dynamics biomechanical models for: (a) the conjoint "iliopsoas" tendon hypothesis and (b) the separate insertion hypothesis. We show that the conjoint model underestimates the iliacus' capacity to generate hip flexion relative to the separate insertion model. Further work reevaluating the primate lower limb (including human) through dissection, needs to be performed to develop those datasets for reconstructing anatomy in fossil hominins using the extant phylogenetic bracket approach, which is frequently used for tetrapods clades outside of paleoanthropology.
Collapse
Affiliation(s)
- Jayc C Sedlmayr
- Department of Cell Biology and Anatomy, School of Medicine, Louisiana State University Health Sciences Center, New Orleans, Louisiana, USA
| | - Karl T Bates
- Department of Musculoskeletal and Ageing Science, University of Liverpool, Liverpool, UK
| | - Jonathan J Wisco
- Department of Anatomy & Neurobiology, Boston University School of Medicine, Boston, Massachusetts, USA
| | - Emma R Schachner
- Department of Cell Biology and Anatomy, School of Medicine, Louisiana State University Health Sciences Center, New Orleans, Louisiana, USA
| |
Collapse
|
12
|
Rhodes MM, Henderson DM, Currie PJ. Maniraptoran pelvic musculature highlights evolutionary patterns in theropod locomotion on the line to birds. PeerJ 2021; 9:e10855. [PMID: 33717681 PMCID: PMC7937347 DOI: 10.7717/peerj.10855] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Accepted: 01/07/2021] [Indexed: 01/07/2023] Open
Abstract
Locomotion is a fundamental aspect of palaeobiology and often investigated by comparing osteological structures and proportions. Previous studies document a stepwise accumulation of avian-like features in theropod dinosaurs that accelerates in the clade Maniraptora. However, the soft tissues that influenced the skeleton offer another perspective on locomotory adaptations. Examination of the pelvis for osteological correlates of hind limb and tail musculature allowed reconstruction of primary locomotory muscles across theropods and their closest extant relatives. Additionally, the areas of pelvic muscle origins were quantified to measure relative differences within and between taxa, to compare morphological features associated with cursoriality, and offer insight into the evolution of locomotor modules. Locomotory inferences based on myology often corroborate those based on osteology, although they occasionally conflict and indicate greater complexity than previously appreciated. Maniraptoran pelvic musculature underscores previous studies noting the multifaceted nature of cursoriality and suggests that a more punctuated step in caudal decoupling occurred at or near the base of Maniraptora.
Collapse
Affiliation(s)
- Matthew M Rhodes
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada
| | | | - Philip J Currie
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada
| |
Collapse
|
13
|
van Beesel J, Hutchinson JR, Hublin JJ, Melillo SM. Exploring the functional morphology of the Gorilla shoulder through musculoskeletal modelling. J Anat 2021; 239:207-227. [PMID: 33629406 PMCID: PMC8197971 DOI: 10.1111/joa.13412] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Revised: 01/27/2021] [Accepted: 02/02/2021] [Indexed: 12/11/2022] Open
Abstract
Musculoskeletal computer models allow us to quantitatively relate morphological features to biomechanical performance. In non‐human apes, certain morphological features have long been linked to greater arm abduction potential and increased arm‐raising performance, compared to humans. Here, we present the first musculoskeletal model of a western lowland gorilla shoulder to test some of these long‐standing proposals. Estimates of moment arms and moments of the glenohumeral abductors (deltoid, supraspinatus and infraspinatus muscles) over arm abduction were conducted for the gorilla model and a previously published human shoulder model. Contrary to previous assumptions, we found that overall glenohumeral abduction potential is similar between Gorilla and Homo. However, gorillas differ by maintaining high abduction moment capacity with the arm raised above horizontal. This difference is linked to a disparity in soft tissue properties, indicating that scapular morphological features like a cranially oriented scapular spine and glenoid do not enhance the abductor function of the gorilla glenohumeral muscles. A functional enhancement due to differences in skeletal morphology was only demonstrated in the gorilla supraspinatus muscle. Contrary to earlier ideas linking a more obliquely oriented scapular spine to greater supraspinatus leverage, our results suggest that increased lateral projection of the greater tubercle of the humerus accounts for the greater biomechanical performance in Gorilla. This study enhances our understanding of the evolution of gorilla locomotion, as well as providing greater insight into the general interaction between anatomy, function and locomotor biomechanics.
Collapse
Affiliation(s)
- Julia van Beesel
- Department of Human Evolution, Max-Planck-Institute for Evolutionary Anthropology, Leipzig, Germany
| | - John R Hutchinson
- Structure & Motion Laboratory, The Royal Veterinary College, Hatfield, UK
| | - Jean-Jacques Hublin
- Department of Human Evolution, Max-Planck-Institute for Evolutionary Anthropology, Leipzig, Germany.,Collège de France, Paris, France
| | - Stephanie M Melillo
- Department of Human Evolution, Max-Planck-Institute for Evolutionary Anthropology, Leipzig, Germany
| |
Collapse
|
14
|
Demuth OE, Rayfield EJ, Hutchinson JR. 3D hindlimb joint mobility of the stem-archosaur Euparkeria capensis with implications for postural evolution within Archosauria. Sci Rep 2020; 10:15357. [PMID: 32958770 PMCID: PMC7506000 DOI: 10.1038/s41598-020-70175-y] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Accepted: 07/24/2020] [Indexed: 12/20/2022] Open
Abstract
Triassic archosaurs and stem-archosaurs show a remarkable disparity in their ankle and pelvis morphologies. However, the implications of these different morphologies for specific functions are still poorly understood. Here, we present the first quantitative analysis into the locomotor abilities of a stem-archosaur applying 3D modelling techniques. μCT scans of multiple specimens of Euparkeria capensis enabled the reconstruction and three-dimensional articulation of the hindlimb. The joint mobility of the hindlimb was quantified in 3D to address previous qualitative hypotheses regarding the stance of Euparkeria. Our range of motion analysis implies the potential for an erect posture, consistent with the hip morphology, allowing the femur to be fully adducted to position the feet beneath the body. A fully sprawling pose appears unlikely but a wide range of hip abduction remained feasible-the hip appears quite mobile. The oblique mesotarsal ankle joint in Euparkeria implies, however, a more abducted hindlimb. This is consistent with a mosaic of ancestral and derived osteological characters in the hindlimb, and might suggest a moderately adducted posture for Euparkeria. Our results support a single origin of a pillar-erect hip morphology, ancestral to Eucrocopoda that preceded later development of a hinge-like ankle joint and a more erect hindlimb posture.
Collapse
Affiliation(s)
- Oliver E Demuth
- School of Earth Sciences, University of Bristol, Wills Memorial Building, Queens Road, Bristol, BS8 1RJ, UK.
- Structure and Motion Laboratory, Department of Comparative Biomedical Sciences, The Royal Veterinary College, Hawkshead Lane, Hatfield, AL9 7TA, UK.
| | - Emily J Rayfield
- School of Earth Sciences, University of Bristol, Wills Memorial Building, Queens Road, Bristol, BS8 1RJ, UK
| | - John R Hutchinson
- Structure and Motion Laboratory, Department of Comparative Biomedical Sciences, The Royal Veterinary College, Hawkshead Lane, Hatfield, AL9 7TA, UK
| |
Collapse
|
15
|
Charles JP, Grant B, D'Août K, Bates KT. Subject-specific muscle properties from diffusion tensor imaging significantly improve the accuracy of musculoskeletal models. J Anat 2020; 237:941-959. [PMID: 32598483 PMCID: PMC7542200 DOI: 10.1111/joa.13261] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2020] [Revised: 04/21/2020] [Accepted: 05/29/2020] [Indexed: 11/29/2022] Open
Abstract
Musculoskeletal modelling is an important platform on which to study the biomechanics of morphological structures in vertebrates and is widely used in clinical, zoological and palaeontological fields. The popularity of this approach stems from the potential to non-invasively quantify biologically important but difficult-to-measure functional parameters. However, while it is known that model predictions are highly sensitive to input values, it is standard practice to build models by combining musculoskeletal data from different sources resulting in 'generic' models for a given species. At present, there are little quantitative data on how merging disparate anatomical data in models impacts the accuracy of these functional predictions. This issue is addressed herein by quantifying the accuracy of both subject-specific human limb models containing individualised muscle force-generating properties and models built using generic properties from both elderly and young individuals, relative to experimental muscle torques obtained from an isokinetic dynamometer. The results show that subject-specific models predict isokinetic muscle torques to a greater degree of accuracy than generic models at the ankle (root-mean-squared error - 7.9% vs. 49.3% in elderly anatomy-based models), knee (13.2% vs. 57.3%) and hip (21.9% vs. 32.8%). These results have important implications for the choice of musculoskeletal properties in future modelling studies, and the relatively high level of accuracy achieved in the subject-specific models suggests that such models can potentially address questions about inter-subject variations of muscle functions. However, despite relatively high levels of overall accuracy, models built using averaged generic muscle architecture data from young, healthy individuals may lack the resolution and accuracy required to study such differences between individuals, at least in certain circumstances. The results do not wholly discourage the continued use of averaged generic data in musculoskeletal modelling studies but do emphasise the need for to maximise the accuracy of input values if studying intra-species form-function relationships in the musculoskeletal system.
Collapse
Affiliation(s)
- James P Charles
- Department of Musculoskeletal and Ageing Science , Institute of Life Course and Medical Sciences, University of Liverpool, Liverpool, UK
| | - Barbara Grant
- Department of Musculoskeletal and Ageing Science , Institute of Life Course and Medical Sciences, University of Liverpool, Liverpool, UK
| | - Kristiaan D'Août
- Department of Musculoskeletal and Ageing Science , Institute of Life Course and Medical Sciences, University of Liverpool, Liverpool, UK
| | - Karl T Bates
- Department of Musculoskeletal and Ageing Science , Institute of Life Course and Medical Sciences, University of Liverpool, Liverpool, UK
| |
Collapse
|
16
|
Tsai HP, Middleton KM, Hutchinson JR, Holliday CM. More than one way to be a giant: Convergence and disparity in the hip joints of saurischian dinosaurs. Evolution 2020; 74:1654-1681. [PMID: 32433795 DOI: 10.1111/evo.14017] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2019] [Revised: 03/15/2020] [Accepted: 04/21/2020] [Indexed: 12/12/2022]
Abstract
Saurischian dinosaurs evolved seven orders of magnitude in body mass, as well as a wide diversity of hip joint morphology and locomotor postures. The very largest saurischians possess incongruent bony hip joints, suggesting that large volumes of soft tissues mediated hip articulation. To understand the evolutionary trends and functional relationships between body size and hip anatomy of saurischians, we tested the relationships among discrete and continuous morphological characters using phylogenetically corrected regression. Giant theropods and sauropods convergently evolved highly cartilaginous hip joints by reducing supraacetabular ossifications, a condition unlike that in early dinosauromorphs. However, transitions in femoral and acetabular soft tissues indicate that large sauropods and theropods built their hip joints in fundamentally different ways. In sauropods, the femoral head possesses irregularly rugose subchondral surfaces for thick hyaline cartilage. Hip articulation was achieved primarily using the highly cartilaginous femoral head and the supraacetabular labrum on the acetabular ceiling. In contrast, theropods covered their femoral head and neck with thinner hyaline cartilage and maintained extensive articulation between the fibrocartilaginous femoral neck and the antitrochanter. These findings suggest that the hip joints of giant sauropods were built to sustain large compressive loads, whereas those of giant theropods experienced compression and shear forces.
Collapse
Affiliation(s)
- Henry P Tsai
- Department of Biomedical Sciences, Missouri State University, Springfield, Missouri, 65897
| | - Kevin M Middleton
- Department of Pathology and Anatomical Sciences, University of Missouri, Columbia, Missouri, 65212
| | - John R Hutchinson
- Structure and Motion Lab, The Royal Veterinary College, Hertfordshire, AL9 7TA, United Kingdom
| | - Casey M Holliday
- Department of Pathology and Anatomical Sciences, University of Missouri, Columbia, Missouri, 65212
| |
Collapse
|
17
|
Fahn-Lai P, Biewener AA, Pierce SE. Broad similarities in shoulder muscle architecture and organization across two amniotes: implications for reconstructing non-mammalian synapsids. PeerJ 2020; 8:e8556. [PMID: 32117627 PMCID: PMC7034385 DOI: 10.7717/peerj.8556] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Accepted: 01/13/2020] [Indexed: 12/18/2022] Open
Abstract
The evolution of upright limb posture in mammals may have enabled modifications of the forelimb for diverse locomotor ecologies. A rich fossil record of non-mammalian synapsids holds the key to unraveling the transition from "sprawling" to "erect" limb function in the precursors to mammals, but a detailed understanding of muscle functional anatomy is a necessary prerequisite to reconstructing postural evolution in fossils. Here we characterize the gross morphology and internal architecture of muscles crossing the shoulder joint in two morphologically-conservative extant amniotes that form a phylogenetic and morpho-functional bracket for non-mammalian synapsids: the Argentine black and white tegu Salvator merianae and the Virginia opossum Didelphis virginiana. By combining traditional physical dissection of cadavers with nondestructive three-dimensional digital dissection, we find striking similarities in muscle organization and architectural parameters. Despite the wide phylogenetic gap between our study species, distal muscle attachments are notably similar, while differences in proximal muscle attachments are driven by modifications to the skeletal anatomy of the pectoral girdle that are well-documented in transitional synapsid fossils. Further, correlates for force production, physiological cross-sectional area (PCSA), muscle gearing (pennation), and working range (fascicle length) are statistically indistinguishable for an unexpected number of muscles. Functional tradeoffs between force production and working range reveal muscle specializations that may facilitate increased girdle mobility, weight support, and active stabilization of the shoulder in the opossum-a possible signal of postural transformation. Together, these results create a foundation for reconstructing the musculoskeletal anatomy of the non-mammalian synapsid pectoral girdle with greater confidence, as we demonstrate by inferring shoulder muscle PCSAs in the fossil non-mammalian cynodont Massetognathus pascuali.
Collapse
Affiliation(s)
- Philip Fahn-Lai
- Museum of Comparative Zoology, Concord Field Station and Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, USA
| | - Andrew A. Biewener
- Concord Field Station and Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, USA
| | - Stephanie E. Pierce
- Museum of Comparative Zoology and Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, USA
| |
Collapse
|
18
|
Słowiak J, Tereshchenko VS, Fostowicz-Frelik Ł. Appendicular skeleton of Protoceratops andrewsi (Dinosauria, Ornithischia): comparative morphology, ontogenetic changes, and the implications for non-ceratopsid ceratopsian locomotion. PeerJ 2019; 7:e7324. [PMID: 31367485 PMCID: PMC6657679 DOI: 10.7717/peerj.7324] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2018] [Accepted: 06/19/2019] [Indexed: 11/20/2022] Open
Abstract
Protoceratops andrewsi is a well-known ceratopsian dinosaur from the Djadokhta Formation (Upper Cretaceous, Mongolia). Since the 1920s, numerous skeletons of different ontogenetic stages from hatchlings to adults, including fully articulated specimens, have been discovered, but the postcranial anatomy of Protoceratops has not been studied in detail. A new, mostly articulated subadult individual provides an excellent opportunity for us to comprehensively describe the anatomy of the limb skeleton, to compare to other ceratopsian dinosaurs, and to study the ontogenetic and intraspecific variation in this species. New data provided by the specimen shed light on the lifestyle of P. andrewsi. The young subadult individuals present an array of morphological characters intermediate between the bipedal Psittacosaurus and fully quadrupedal adult P. andrewsi. We compare these observations with a broad range of non-ceratopsid Neoceratopsia (of various locomotor adaptations) and Psittacosauridae (obligate bipeds), which gives us insight into the evolution of the skeletal characters informative for the postural change in ceratopsian dinosaurs.
Collapse
Affiliation(s)
- Justyna Słowiak
- Department of Evolutionary Paleobiology, Institute of Paleobiology, Polish Academy of Sciences, Warsaw, Poland
| | - Victor S Tereshchenko
- Laboratory of Paleoherpetology, Paleontological Institute, Russian Academy of Sciences, Moscow, Russia
| | - Łucja Fostowicz-Frelik
- Department of Evolutionary Paleobiology, Institute of Paleobiology, Polish Academy of Sciences, Warsaw, Poland.,Key Laboratory of Vertebrate Evolution and Human Origins, Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, Beijing, China
| |
Collapse
|
19
|
Zhang Y, Wang K, Chen S, Liu D, Xing H. Osteological Re‐Assessment and Taxonomic Revision of
“Tanius laiyangensis”
(Ornithischia: Hadrosauroidea) from the Upper Cretaceous of Shandong, China. Anat Rec (Hoboken) 2019; 303:790-800. [DOI: 10.1002/ar.24097] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2018] [Revised: 10/07/2018] [Accepted: 10/26/2018] [Indexed: 11/06/2022]
Affiliation(s)
- Yu‐Guang Zhang
- Beijing Museum of Natural HistoryBeijing Academy of Science and Technology Beijing People's Republic of China
| | - Ke‐Bai Wang
- Zhucheng Dinosaur MuseumDinosaur Research Center of Zhucheng Zhucheng Shandong People's Republic of China
| | - Shu‐Qing Chen
- Zhucheng Dinosaur MuseumDinosaur Research Center of Zhucheng Zhucheng Shandong People's Republic of China
| | - Di Liu
- Beijing Museum of Natural HistoryBeijing Academy of Science and Technology Beijing People's Republic of China
| | - Hai Xing
- Beijing Museum of Natural HistoryBeijing Academy of Science and Technology Beijing People's Republic of China
| |
Collapse
|
20
|
Persons WS, Currie PJ. The Anatomical and Functional Evolution of the Femoral Fourth Trochanter in Ornithischian Dinosaurs. Anat Rec (Hoboken) 2019; 303:1146-1157. [PMID: 30776198 DOI: 10.1002/ar.24094] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2018] [Revised: 09/11/2018] [Accepted: 10/02/2018] [Indexed: 11/07/2022]
Abstract
The femoral fourth trochanter is the attachment site of the caudofemoralis musculature, which is the primary hindlimb retractor in most non-avian dinosaurs. Early ornithischian dinosaurs are uniquely characterized by a fourth trochanter with a prominent pendant process. Throughout the evolution of ornithischians, the fourth trochanter repeatedly converged on two major morphological changes: (1) the distal migration of the trochanter down the femoral shaft and (2) the loss of the pendant process. Both changes, as well as the original evolution of the pendant form, relate to a single major functional shift emphasizing caudofemoral leverage. Direct evidence of muscle scarring across the surface of the pendant process affirms that it served to extend the attachment of the primary caudofemoralis brevis tendon distally. A proximally located fourth trochanter is the basal condition in dinosaurs and other archosaurs, and the development of a pendant process lengthened the functional lever arm with regard to the insertion of the caudofemoralis. This adaptation afforded improved mechanical advantage, perhaps beneficial in the context of the newly assumed herbivorous diets of basal ornithischians. As some derived ornithischians increased in body size, a high-leverage system with a more distal caudofemoralis attachment evolved. In some groups, the fourth trochanter as a whole descended down the femur, eventually reaching a point where the pendant process was unnecessary. Sauropodomorphs, the other great lineage of dinosaur herbivores, converged on the same high-leverage distal fourth trochanter arrangement, but without first transitioning through a prominent pendant form. Anat Rec, 303:1146-1157, 2020. © 2019 Wiley Periodicals, Inc.
Collapse
Affiliation(s)
- Walter S Persons
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada
| | - Philip J Currie
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada
| |
Collapse
|
21
|
Klinkhamer AJ, Mallison H, Poropat SF, Sloan T, Wroe S. Comparative Three‐Dimensional Moment Arm Analysis of the Sauropod Forelimb: Implications for the Transition to a Wide‐Gauge Stance in Titanosaurs. Anat Rec (Hoboken) 2018; 302:794-817. [DOI: 10.1002/ar.23977] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2018] [Revised: 06/28/2018] [Accepted: 08/15/2018] [Indexed: 01/22/2023]
Affiliation(s)
- Ada J. Klinkhamer
- Function, Evolution and Anatomy Research Laboratory School of Environmental and Rural Science, University of New England Armidale New South Wales Australia
- Australian Age of Dinosaurs Museum of Natural History Winton Queensland Australia
| | | | - Stephen F. Poropat
- Australian Age of Dinosaurs Museum of Natural History Winton Queensland Australia
- Department of Chemistry and Biotechnology Swinburne University of Technology Hawthorn Victoria Australia
| | - Trish Sloan
- Australian Age of Dinosaurs Museum of Natural History Winton Queensland Australia
| | - Stephen Wroe
- Function, Evolution and Anatomy Research Laboratory School of Environmental and Rural Science, University of New England Armidale New South Wales Australia
| |
Collapse
|
22
|
Klinkhamer AJ, Mallison H, Poropat SF, Sinapius GH, Wroe S. Three‐Dimensional Musculoskeletal Modeling of the Sauropodomorph Hind Limb: The Effect of Postural Change on Muscle Leverage. Anat Rec (Hoboken) 2018; 301:2145-2163. [DOI: 10.1002/ar.23950] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2018] [Revised: 05/14/2018] [Accepted: 06/01/2018] [Indexed: 12/27/2022]
Affiliation(s)
- Ada J. Klinkhamer
- Function, Evolution, and Anatomy Research Lab, School of Environmental and Rural Science University of New England Armidale New South Wales Australia
- Australian Age of Dinosaurs Museum of Natural History Winton Queenland Australia
| | | | - Stephen F. Poropat
- Australian Age of Dinosaurs Museum of Natural History Winton Queenland Australia
- Faculty of Science, Engineering, and Technology Swinburne University of Technology Hawthorn Victoria Australia
| | - George H.K. Sinapius
- Australian Age of Dinosaurs Museum of Natural History Winton Queenland Australia
| | - Stephen Wroe
- Function, Evolution, and Anatomy Research Lab, School of Environmental and Rural Science University of New England Armidale New South Wales Australia
| |
Collapse
|
23
|
Goh C, Blanchard ML, Crompton RH, Gunther MM, Macaulay S, Bates KT. A 3D musculoskeletal model of the western lowland gorilla hind limb: moment arms and torque of the hip, knee and ankle. J Anat 2017; 231:568-584. [PMID: 28718217 PMCID: PMC5603783 DOI: 10.1111/joa.12651] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/06/2017] [Indexed: 11/28/2022] Open
Abstract
Three-dimensional musculoskeletal models have become increasingly common for investigating muscle moment arms in studies of vertebrate locomotion. In this study we present the first musculoskeletal model of a western lowland gorilla hind limb. Moment arms of individual muscles around the hip, knee and ankle were compared with previously published data derived from the experimental tendon travel method. Considerable differences were found which we attribute to the different methodologies in this specific case. In this instance, we argue that our 3D model provides more accurate and reliable moment arm data than previously published data on the gorilla because our model incorporates more detailed consideration of the 3D geometry of muscles and the geometric constraints that exist on their lines-of-action about limb joints. Our new data have led us to revaluate the previous conclusion that muscle moment arms in the gorilla hind limb are optimised for locomotion with crouched or flexed limb postures. Furthermore, we found that bipedalism and terrestrial quadrupedalism coincided more regularly with higher moment arms and torque around the hip, knee and ankle than did vertical climbing. This indicates that the ability of a gorilla to walk bipedally is not restricted by musculoskeletal adaptations for quadrupedalism and vertical climbing, at least in terms of moment arms and torque about hind limb joints.
Collapse
Affiliation(s)
- Colleen Goh
- Department of Musculoskeletal Biology, Institute of Aging and Chronic Disease, University of Liverpool, Liverpool, UK
| | | | - Robin H Crompton
- Department of Musculoskeletal Biology, Institute of Aging and Chronic Disease, University of Liverpool, Liverpool, UK
| | - Michael M Gunther
- Department of Musculoskeletal Biology, Institute of Aging and Chronic Disease, University of Liverpool, Liverpool, UK
| | - Sophie Macaulay
- Department of Musculoskeletal Biology, Institute of Aging and Chronic Disease, University of Liverpool, Liverpool, UK
| | - Karl T Bates
- Department of Musculoskeletal Biology, Institute of Aging and Chronic Disease, University of Liverpool, Liverpool, UK
| |
Collapse
|
24
|
Digital dissection and three-dimensional interactive models of limb musculature in the Australian estuarine crocodile (Crocodylus porosus). PLoS One 2017; 12:e0175079. [PMID: 28384201 PMCID: PMC5383063 DOI: 10.1371/journal.pone.0175079] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2016] [Accepted: 03/20/2017] [Indexed: 01/07/2023] Open
Abstract
Digital dissection is a relatively new technique that has enabled scientists to gain a better understanding of vertebrate anatomy. It can be used to rapidly disseminate detailed, three-dimensional information in an easily accessible manner that reduces the need for destructive, traditional dissections. Here we present the results of a digital dissection on the appendicular musculature of the Australian estuarine crocodile (Crocodylus porosus). A better understanding of this until now poorly known system in C. porosus is important, not only because it will expand research into crocodilian locomotion, but because of its potential to inform muscle reconstructions in dinosaur taxa. Muscles of the forelimb and hindlimb are described and three-dimensional interactive models are included based on CT and MRI scans as well as fresh-tissue dissections. Differences in the arrangement of musculature between C. porosus and other groups within the Crocodylia were found. In the forelimb, differences are restricted to a single tendon of origin for triceps longus medialis. For the hindlimb, a reduction in the number of heads of ambiens was noted as well as changes to the location of origin and insertion for iliofibularis and gastrocnemius externus.
Collapse
|
25
|
Charles JP, Cappellari O, Spence AJ, Wells DJ, Hutchinson JR. Muscle moment arms and sensitivity analysis of a mouse hindlimb musculoskeletal model. J Anat 2016; 229:514-35. [PMID: 27173448 PMCID: PMC5013061 DOI: 10.1111/joa.12461] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/02/2016] [Indexed: 12/25/2022] Open
Abstract
Musculoskeletal modelling has become a valuable tool with which to understand how neural, muscular, skeletal and other tissues are integrated to produce movement. Most musculoskeletal modelling work has to date focused on humans or their close relatives, with few examples of quadrupedal animal limb models. A musculoskeletal model of the mouse hindlimb could have broad utility for questions in medicine, genetics, locomotion and neuroscience. This is due to this species’ position as a premier model of human disease, having an array of genetic tools for manipulation of the animal in vivo, and being a small quadruped, a category for which few models exist. Here, the methods used to develop the first three‐dimensional (3D) model of a mouse hindlimb and pelvis are described. The model, which represents bones, joints and 39 musculotendon units, was created through a combination of previously gathered muscle architecture data from microdissections, contrast‐enhanced micro‐computed tomography (CT) scanning and digital segmentation. The model allowed muscle moment arms as well as muscle forces to be estimated for each musculotendon unit throughout a range of joint rotations. Moment arm analysis supported the reliability of musculotendon unit placement within the model, and comparison to a previously published rat hindlimb model further supported the model's reliability. A sensitivity analysis performed on both the force‐generating parameters and muscle's attachment points of the model indicated that the maximal isometric muscle moment is generally most sensitive to changes in either tendon slack length or the coordinates of insertion, although the degree to which the moment is affected depends on several factors. This model represents the first step in the creation of a fully dynamic 3D computer model of the mouse hindlimb and pelvis that has application to neuromuscular disease, comparative biomechanics and the neuromechanical basis of movement. Capturing the morphology and dynamics of the limb, it enables future dissection of the complex interactions between the nervous and musculoskeletal systems as well as the environment.
Collapse
Affiliation(s)
- James P Charles
- Neuromuscular Diseases Group, Comparative Biomedical Sciences, Royal Veterinary College, London, UK.,Structure and Motion Lab, Comparative Biomedical Sciences, Royal Veterinary College, Hatfield, UK
| | - Ornella Cappellari
- Neuromuscular Diseases Group, Comparative Biomedical Sciences, Royal Veterinary College, London, UK
| | - Andrew J Spence
- Structure and Motion Lab, Comparative Biomedical Sciences, Royal Veterinary College, Hatfield, UK.,Department of Bioengineering, College of Engineering, Temple University, Philadelphia, PA, USA
| | - Dominic J Wells
- Neuromuscular Diseases Group, Comparative Biomedical Sciences, Royal Veterinary College, London, UK
| | - John R Hutchinson
- Structure and Motion Lab, Comparative Biomedical Sciences, Royal Veterinary College, Hatfield, UK.
| |
Collapse
|
26
|
Porro LB, Witmer LM, Barrett PM. Digital preparation and osteology of the skull of Lesothosaurus diagnosticus (Ornithischia: Dinosauria). PeerJ 2015; 3:e1494. [PMID: 26713245 PMCID: PMC4690377 DOI: 10.7717/peerj.1494] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2015] [Accepted: 11/22/2015] [Indexed: 11/20/2022] Open
Abstract
Several skulls of the ornithischian dinosaur Lesothosaurus diagnosticus (Lower Jurassic, southern Africa) are known, but all are either incomplete, deformed, or incompletely prepared. This has hampered attempts to provide a comprehensive description of skull osteology in this crucial early dinosaurian taxon. Using visualization software, computed tomographic scans of the Lesothosaurus syntypes were digitally segmented to remove matrix, and identify and separate individual cranial and mandibular bones, revealing new anatomical details such as sutural morphology and the presence of several previously undescribed elements. Together with visual inspection of exposed skull bones, these CT data enable a complete description of skull anatomy in this taxon. Comparisons with our new data suggest that two specimens previously identified as Lesothosaurus sp. (MNHN LES 17 and MNHN LES 18) probably represent additional individuals of Lesothosaurus diagnosticus.
Collapse
Affiliation(s)
- Laura B Porro
- Department of Comparative Biomedical Sciences, Royal Veterinary College , Hatfield , United Kingdom
| | - Lawrence M Witmer
- Department of Biomedical Sciences, Heritage College of Osteopathic Medicine, Ohio University , Athens, OH , United States
| | - Paul M Barrett
- Department of Earth Sciences, Natural History Museum , London , United Kingdom
| |
Collapse
|
27
|
Bates K, Maidment SCR, Schachner ER, Barrett PM. Comments and corrections on 3D modeling studies of locomotor muscle moment arms in archosaurs. PeerJ 2015; 3:e1272. [PMID: 26500810 PMCID: PMC4614809 DOI: 10.7717/peerj.1272] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2015] [Accepted: 09/05/2015] [Indexed: 11/25/2022] Open
Abstract
In a number of recent studies we used computer modeling to investigate the evolution of muscle leverage (moment arms) and function in extant and extinct archosaur lineages (crocodilians, dinosaurs including birds and pterosaurs). These studies sought to quantify the level of disparity and convergence in muscle moment arms during the evolution of bipedal and quadrupedal posture in various independent archosaur lineages, and in doing so further our understanding of changes in anatomy, locomotion and ecology during the group’s >250 million year evolutionary history. Subsequent work by others has led us to re-evaluate our models, which revealed a methodological error that impacted on the results obtained from the abduction–adduction and long-axis rotation moment arms in our published studies. In this paper we present corrected abduction–adduction and long axis rotation moment arms for all our models, and evaluate the impact of this new data on the conclusions of our previous studies. We find that, in general, our newly corrected data differed only slightly from that previously published, with very few qualitative changes in muscle moments (e.g., muscles originally identified as abductors remained abductors). As a result the majority of our previous conclusions regarding the functional evolution of key muscles in these archosaur groups are upheld.
Collapse
Affiliation(s)
- Karl Bates
- Department of Musculoskeletal Biology, University of Liverpool , Liverpool , United Kingdom
| | - Susannah C R Maidment
- Department of Earth Science and Engineering, Imperial College , London , United Kingdom
| | - Emma R Schachner
- Department of Veterinary Clinical Sciences, Louisiana State University , Baton Rouge, LA , United States of America
| | - Paul M Barrett
- Department of Earth Sciences, The Natural History Museum , London , United Kingdom
| |
Collapse
|
28
|
Hutchinson JR, Rankin JW, Rubenson J, Rosenbluth KH, Siston RA, Delp SL. Musculoskeletal modelling of an ostrich (Struthio camelus) pelvic limb: influence of limb orientation on muscular capacity during locomotion. PeerJ 2015; 3:e1001. [PMID: 26082859 PMCID: PMC4465956 DOI: 10.7717/peerj.1001] [Citation(s) in RCA: 67] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2014] [Accepted: 05/15/2015] [Indexed: 12/03/2022] Open
Abstract
We developed a three-dimensional, biomechanical computer model of the 36 major pelvic limb muscle groups in an ostrich (Struthio camelus) to investigate muscle function in this, the largest of extant birds and model organism for many studies of locomotor mechanics, body size, anatomy and evolution. Combined with experimental data, we use this model to test two main hypotheses. We first query whether ostriches use limb orientations (joint angles) that optimize the moment-generating capacities of their muscles during walking or running. Next, we test whether ostriches use limb orientations at mid-stance that keep their extensor muscles near maximal, and flexor muscles near minimal, moment arms. Our two hypotheses relate to the control priorities that a large bipedal animal might evolve under biomechanical constraints to achieve more effective static weight support. We find that ostriches do not use limb orientations to optimize the moment-generating capacities or moment arms of their muscles. We infer that dynamic properties of muscles or tendons might be better candidates for locomotor optimization. Regardless, general principles explaining why species choose particular joint orientations during locomotion are lacking, raising the question of whether such general principles exist or if clades evolve different patterns (e.g., weighting of muscle force-length or force-velocity properties in selecting postures). This leaves theoretical studies of muscle moment arms estimated for extinct animals at an impasse until studies of extant taxa answer these questions. Finally, we compare our model's results against those of two prior studies of ostrich limb muscle moment arms, finding general agreement for many muscles. Some flexor and extensor muscles exhibit self-stabilization patterns (posture-dependent switches between flexor/extensor action) that ostriches may use to coordinate their locomotion. However, some conspicuous areas of disagreement in our results illustrate some cautionary principles. Importantly, tendon-travel empirical measurements of muscle moment arms must be carefully designed to preserve 3D muscle geometry lest their accuracy suffer relative to that of anatomically realistic models. The dearth of accurate experimental measurements of 3D moment arms of muscles in birds leaves uncertainty regarding the relative accuracy of different modelling or experimental datasets such as in ostriches. Our model, however, provides a comprehensive set of 3D estimates of muscle actions in ostriches for the first time, emphasizing that avian limb mechanics are highly three-dimensional and complex, and how no muscles act purely in the sagittal plane. A comparative synthesis of experiments and models such as ours could provide powerful synthesis into how anatomy, mechanics and control interact during locomotion and how these interactions evolve. Such a framework could remove obstacles impeding the analysis of muscle function in extinct taxa.
Collapse
Affiliation(s)
- John R. Hutchinson
- Structure and Motion Laboratory, Department of Comparative Biomedical Sciences, The Royal Veterinary College, University of London, Hatfield, Hertfordshire, United Kingdom
- Bioengineering Department, Stanford University, Stanford, CA, USA
| | - Jeffery W. Rankin
- Structure and Motion Laboratory, Department of Comparative Biomedical Sciences, The Royal Veterinary College, University of London, Hatfield, Hertfordshire, United Kingdom
| | - Jonas Rubenson
- School of Sport Science, Exercise and Health, The University of Western Australia, Perth, WA, Australia
- Department of Kinesiology, The Pennsylvania State University, University Park, PA, USA
| | | | - Robert A. Siston
- Bioengineering Department, Stanford University, Stanford, CA, USA
- Department of Mechanical and Aerospace Engineering, The Ohio State University, Columbus, OH, USA
| | - Scott L. Delp
- Bioengineering Department, Stanford University, Stanford, CA, USA
| |
Collapse
|
29
|
Tsai HP, Holliday CM. Articular soft tissue anatomy of the archosaur hip joint: Structural homology and functional implications. J Morphol 2014; 276:601-30. [DOI: 10.1002/jmor.20360] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2014] [Revised: 11/25/2014] [Accepted: 12/05/2014] [Indexed: 11/05/2022]
Affiliation(s)
- Henry P. Tsai
- Department of Pathology and Anatomical Sciences; University of Missouri; Columbia Missouri 65212
| | - Casey M. Holliday
- Department of Pathology and Anatomical Sciences; University of Missouri; Columbia Missouri 65212
| |
Collapse
|
30
|
Maidment SCR, Bates KT, Falkingham PL, VanBuren C, Arbour V, Barrett PM. Locomotion in ornithischian dinosaurs: an assessment using three-dimensional computational modelling. Biol Rev Camb Philos Soc 2013; 89:588-617. [DOI: 10.1111/brv.12071] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2012] [Revised: 10/05/2013] [Accepted: 10/14/2013] [Indexed: 11/30/2022]
Affiliation(s)
| | - Karl T. Bates
- Department of Musculoskeletal Biology II; Institute of Aging and Chronic Disease, University of Liverpool; Sherrington Buildings, Ashton Street Liverpool L69 3GE U.K
| | - Peter L. Falkingham
- Department of Comparative Biomedical Sciences; Structure and Motion Laboratory, Royal Veterinary College, Hawkshead Lane, Hatfield, Hertfordshire, AL9 7TA; U.K
- Department of Ecology and Evolutionary Biology, Division of Biology and Medicine; Brown University, 80 Waterman Street; Providence RI 02912 U.S.A
| | - Collin VanBuren
- Department of Ecology and Evolutionary Biology; University of Toronto; 25 Willcocks Street Toronto Ontario M5S 3B2 Canada
| | - Victoria Arbour
- Department of Biological Sciences; University of Alberta; 11145 Saskatchewan Drive Edmonton Alberta T6G 2EG Canada
| | - Paul M. Barrett
- Department of Earth Sciences; The Natural History Museum; Cromwell Road London SW7 5BD U.K
| |
Collapse
|
31
|
Maidment SCR, Linton DH, Upchurch P, Barrett PM. Limb-bone scaling indicates diverse stance and gait in quadrupedal ornithischian dinosaurs. PLoS One 2012; 7:e36904. [PMID: 22666333 PMCID: PMC3358279 DOI: 10.1371/journal.pone.0036904] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2011] [Accepted: 04/09/2012] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND The most primitive ornithischian dinosaurs were small bipeds, but quadrupedality evolved three times independently in the clade. The transition to quadrupedality from bipedal ancestors is rare in the history of terrestrial vertebrate evolution, and extant analogues do not exist. Constraints imposed on quadrupedal ornithischians by their ancestral bipedal bauplan remain unexplored, and consequently, debate continues about their stance and gait. For example, it has been proposed that some ornithischians could run, while others consider that none were cursorial. METHODOLOGY/PRINCIPAL FINDINGS Drawing on biomechanical concepts of limb bone scaling and locomotor theory developed for extant taxa, we use the largest dataset of ornithischian postcranial measurements so far compiled to examine stance and gait in quadrupedal ornithischians. Differences in femoral midshaft eccentricity in hadrosaurs and ceratopsids may indicate that hadrosaurs placed their feet on the midline during locomotion, while ceratopsids placed their feet more laterally, under the hips. More robust humeri in the largest ceratopsids relative to smaller taxa may be due to positive allometry in skull size with body mass in ceratopsids, while slender humeri in the largest stegosaurs may be the result of differences in dermal armor distribution within the clade. Hadrosaurs are found to display the most cursorial morphologies of the quadrupedal ornithischian cades, indicating higher locomotor performance than in ceratopsids and thyreophorans. CONCLUSIONS/SIGNIFICANCE Limb bone scaling indicates that a previously unrealised diversity of stances and gaits were employed by quadrupedal ornithischians despite apparent convergence in limb morphology. Grouping quadrupedal ornithischians together as a single functional group hides this disparity. Differences in limb proportions and scaling are likely due to the possession of display structures such as horns, frills and dermal armor that may have affected the center of mass of the animal, and differences in locomotor behaviour such as migration, predator escape or home range size.
Collapse
|