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Journal of Morphology Jun 2023A comparative analysis of the forelimb myology of two neotropical procyonids (Nasua nasua and Procyon cancrivorus) was performed to assess how observed differences in...
Functional and phylogenetic interpretation of the forelimb myology of two South American carnivorans, the ring-tailed coati (Nasua nasua) and crab-eating raccoon (Procyon cancrivorus).
A comparative analysis of the forelimb myology of two neotropical procyonids (Nasua nasua and Procyon cancrivorus) was performed to assess how observed differences in their myological configuration would be related to their diverse ecological behaviors and phylogeny. Although both species are associated with the arboreal substrate, N. nasua is a more agile climber that usually digs; whereas P. cancrivorus spends most of its time on the ground foraging, climbing on the trees as shelter and is a good swimmer. Here, myological descriptions, muscle maps, phylogenetic optimizations, and muscle mass data of the forelimb of these two procyonids are presented. The main functional muscular groups are discussed in a comparative framework with other carnivorans that present a wide ecological diversity. Also, muscular characters were mapped onto a phylogeny to explore their evolution and to obtain ancestral state reconstructions. Results indicate clear myological differences among the two neotropical procyonids associated with their ecological preferences. One of the most remarkable anatomical differences is the arrangement and relative mass of the extrinsic musculature, mainly the musculus rhomboideus and the delto-pectoral complexes. In Nasua nasua, these suggested a greater stability in their shoulder girdle for climbing and digging and probably would provide stronger neck and head movements when they use them for foraging on the ground. Conversely, P. cancrivorus has a different extrinsic muscular configuration, which would allow an increment on the stride length and faster movements of the forelimb associated with more frequent terrestrial gaits. Also, significant differences are observed in the distal musculature, associated with strong movements of forepaws when climbing and digging in N. nasua; whereas, P. cancrivorus configuration suggested precise forearm and digits movements, related to manipulation of food items when they are catching prey or feeding. Most of the codified features of P. cancrivorus would reflect retention of plesiomorphies acquired in the common ancestor of caniforms or arctoids, whereas N. nasua shows derived traits, particularly in the proximal forelimb region. The present work increases the information available on the myology of these particular taxa and extant generalized arctoid models in general. The analyses presented here will be useful both for other comparative myological studies (morpho-functional and phylogenetic) and for muscular reconstruction in extinct procyonids, as well as other carnivorans.
Topics: Animals; Procyonidae; Raccoons; Phylogeny; Brachyura; Forelimb; South America
PubMed: 37183491
DOI: 10.1002/jmor.21587 -
Ecology and Evolution Oct 2022Ecological character displacement between the sexes, and sexual selection, integrate into a convergent set of factors that produce sexual variation. Ecologically...
Sexually mediated phenotypic variation within and between sexes as a continuum structured by ecology: The mosaic nature of skeletal variation across body regions in Threespine stickleback ( L.).
Ecological character displacement between the sexes, and sexual selection, integrate into a convergent set of factors that produce sexual variation. Ecologically modulated, sexually mediated variation within and between sexes may be a major contributor to the amount of total variation that selection can act on in species. Threespine stickleback () display rapid adaptive responses and sexual variation in many phenotypic traits. We examined phenotypic variation in the skull, pectoral and pelvic girdles of threespine stickleback from two freshwater and two coastal marine sites on the Sunshine Coast of British Columbia, Canada, using an approach that avoids a priori assumptions about bimodal patterns of variation. We quantified shape and size of the cranial, pectoral and pelvic regions of sticklebacks in marine and freshwater habitats using 3D geometric morphometrics and an index of sexually mediated variation. We show that the expression of phenotypic variation is structured in part by the effects of both habitat marine vs freshwater and the effects of individual sites within each habitat. Relative size exerts variable influence, and patterns of phenotypic variation associated with sex vary among body regions. This fine-grained quantification of sexually mediated variation in the context of habitat difference and different anatomical structures indicates a complex relationship between genetically inferred sex and environmental factors, demonstrating that the interplay between shared genetic background and sexually mediated, ecologically based selective pressures structures the phenotypic expression of complex traits.
PubMed: 36254299
DOI: 10.1002/ece3.9367 -
Mymensingh Medical Journal : MMJ Oct 2022Clavicle is an upper limb locomotory bone which helps in formation of pectoral girdle and connected the upper limb with axial skeleton. There is no baseline data of...
Clavicle is an upper limb locomotory bone which helps in formation of pectoral girdle and connected the upper limb with axial skeleton. There is no baseline data of clavicle in contrast to demographic variation in our country, so the study was designed to obtain baseline data on clavicle for anthropological, forensic and clinical use. This descriptive cross-sectional study was done among 150 (65 right and 85 left) fully ossified dry human clavicle in Mymensingh Medical College, Mymensingh, Bangladesh from January 2020 to December 2020. Sample was collected by the help of nonrandom purposive sampling technique from Department of Anatomy of Mymensingh Medical College and Community Based Medical College, Bangladesh, Mymensingh. The parameters were the antero-posterior diameter and vertical diameter of sternal and acromial ends of clavicle, measured with the help of digital vernier slide caliper and expressed in millimeter. In the current study the mean±SD antero-posterior diameter of sternal end of 65 clavicles of right side was 21.97±2.889mm and 85 clavicles of left side were 20.30±3.459mm. The mean±SD antero-posterior diameter of acromial end of 65 right sided clavicles was 21.96±5.161mm and 85 clavicles of left side were 21.00±4.002mm. Correlation was done in between antero-posterior diameter and vertical diameter of sternal end of clavicle and the differences were highly significant on both sides. Similarly, when correlation was done for the acromial end of clavicle the difference was found non-significant on right side and highly significant on left side.
Topics: Bangladesh; Clavicle; Cross-Sectional Studies; Humans; Osteogenesis; Sternum
PubMed: 36189530
DOI: No ID Found -
Development & Reproduction Mar 2021This study was carried out to observe the development of the autonomous skeletal development of the . Total length (TL) of larvae 3 days after hatching (DAH) were mean...
This study was carried out to observe the development of the autonomous skeletal development of the . Total length (TL) of larvae 3 days after hatching (DAH) were mean TL of 3.34 mm, with a line-shaped parasphenoid ossification in the cranium and basioccipital ossification in the back. The 10 DAH larvae had a mean TL of 5.20 mm, with the number of caudal vertebrae increasing to 15. The urostyle and two hypural bones in the lower part also began to ossify. The 23 DAH juveniles had a mean TL of 8.47 mm. The pectoral girdle's skeleton was completed as the scapula and coracoid were ossified. The pelvic girdle also fully supported the ventral fin as its ossification was completed. and showed similar characteristics in terms of the anus location of hatched larvae, number of myotomes, and melanophore distribution during the morphological development of the larvae and juveniles. However, this study confirmed differences in the development of the vertebrae and urostyle bone.
PubMed: 33977173
DOI: 10.12717/DR.2021.25.1.33 -
Royal Society Open Science Jul 2019Recently, comprehensive morphological datasets including nearly all the well-recognized Mesozoic birds became available, making it feasible for statistically rigorous...
Recently, comprehensive morphological datasets including nearly all the well-recognized Mesozoic birds became available, making it feasible for statistically rigorous methods to unveil finer evolutionary patterns during early avian evolution. Here, we exploited the advantage of Bayesian tip dating under relaxed morphological clocks to estimate both the divergence times and evolutionary rates while accounting for their uncertainties. We further subdivided the characters into six body regions (i.e. skull, axial skeleton, pectoral girdle and sternum, forelimb, pelvic girdle and hindlimb) to assess evolutionary rate heterogeneity both along the lineages and across partitions. We observed extremely high rates of morphological character changes during early avian evolution, and the clock rates are quite heterogeneous among the six regions. The branch subtending Pygostylia shows an extremely high rate in the axial skeleton, while the branches subtending Ornithothoraces and Enantiornithes show notably high rates in the pectoral girdle and sternum and moderately high rates in the forelimb. The extensive modifications in these body regions largely correspond to refinement of the flight capability. This study reveals the power and flexibility of Bayesian tip dating implemented in MrBayes to investigate evolutionary dynamics in deep time.
PubMed: 31417697
DOI: 10.1098/rsos.182062 -
Anatomical Record (Hoboken, N.J. : 2007) Dec 2022Exquisite discoveries and new interpretations regarding an enigmatic group of cursorial avemetatarsalians led to a new phylogenetic hypothesis regarding pterosaur...
Exquisite discoveries and new interpretations regarding an enigmatic group of cursorial avemetatarsalians led to a new phylogenetic hypothesis regarding pterosaur affinities. Previously thought to be dinosaur precursors, lagerpetids are now considered to be the closest relatives to pterosaurs. This new hypothesis sheds light on a new explorable field, especially regarding the character acquisition and evolution within the pterosaur lineage. In the present study, the morphospace occupation of distinct skeletal regions of lagerpetids within the morphological spectrum of avemetatarsalians is investigated. This approach indicates which portions of the skeleton are more similar to the anatomy of pterosaurs and which portions present different homoplastic signals. The analyses demonstrate that the craniomandibular traits of lagerpetids are pterosaur-like, the pectoral girdle and forelimb are dinosauromorph-like and the axial skeleton and the pelvic girdle and hindlimb are unique and highly specialized among the analyzed sample. So, despite the close phylogenetic relationships, the postcranial skeleton of lagerpetids and pterosaurs are very different. The occurrence of two distinct and highly specialized groups of pterosauromorphs coexisting with a wide ecological range of dinosauromorphs during the Triassic suggests pressure for new niches occupation.
Topics: Animals; Fossils; Phylogeny; Biological Evolution; Dinosaurs; Bone and Bones; Occupations
PubMed: 35199946
DOI: 10.1002/ar.24904 -
Journal of Aquatic Animal Health Dec 2021The purpose of this study was to determine the optimal imaging protocol for contrast-enhanced computed tomography (CECT) using micro-CT (μ-CT) for the posterior...
The purpose of this study was to determine the optimal imaging protocol for contrast-enhanced computed tomography (CECT) using micro-CT (μ-CT) for the posterior cardinal vein (PCV), dorsal aorta (DA), hepatic portal vein (HPV), kidney, liver, cephalic arteries (CAs), and gills of Cloudy Catsharks Scyliorhinus torazame. Additionally, we examined the availability of CECT screening for the coelomic organs. Different doses of iopamidol (100, 300, 500, and 700 mg iodine [mgI]/kg) were administered intravenously for 20 s in six sharks. The CT scans from the pectoral girdle to the pelvic girdle were performed at 0-600 s after administration. Contrast-enhanced CT imaging of the CAs, gills, and coelomic organs was examined. Assessment of the signal enhancement value revealed that the PCV was easily visualized with all contrast doses at 25 s. The CAs, gills, and DA were visible at a slightly higher dose (CAs and gills: 200 mgI/kg at 40 s; DA: 300 mgI/kg at 50 s). The HPV was obvious at a dose of at least 500 mgI/kg after a 150-s delay. The parenchyma of the kidney had a contrast effect at 300 mgI/kg, 150 s after the contrast effect of the renal portal system disappeared. The liver, which stores a lot of lipids, had poor overall contrast enhancement that was optimized at the highest dose of 700 mgI/kg. Contrast-enhanced CT screening at 700 mgI/kg and 150 s is likely to obtain the optimal imaging of the reproductive organs, such as the ovary, oviducal gland, uterus, and testis. The present findings can be applied not only to clinical practice but also to academic research and education on elasmobranchs in aquariums.
Topics: Animals; Contrast Media; Elasmobranchii; Female; Iodine; Iopamidol; Male; X-Ray Microtomography
PubMed: 34363233
DOI: 10.1002/aah.10143 -
Scientific Reports Jan 2022We here report on a well-preserved juvenile lizard specimen in Albian amber (ca. 110 mya) from the Hkamti site (Myanmar). This new taxon is represented by an...
We here report on a well-preserved juvenile lizard specimen in Albian amber (ca. 110 mya) from the Hkamti site (Myanmar). This new taxon is represented by an articulated skull and the anterior portion of the trunk, including the pectoral girdle and forelimbs. The scleral ossicles and eyelid are also visible, and the specimen exhibits pristine detail of the integument (of both head and body). In a combined molecular and morphological analysis, it was consistently recovered as a scincoid lizard (Scinciformata), as sister to Tepexisaurus + Xantusiidae. However, the phylogenetic position of the new taxon should be interpreted with caution as the holotype is an immature individual. We explored the possibility of miscoding ontogenetically variable characters by running alternative analyses in which these characters were scored as missing data for our taxon. With the exception of one tree, in which it was sister to Amphisbaenia, the specimen was recovered as a Pan-xantusiid. Moreover, we cannot rule out the possibility that it represents a separate lineage of uncertain phylogenetic position, as it is the case for many Jurassic and Cretaceous taxa. Nonetheless, this fossil offers a rare opportunity to glimpse the external appearance of one group of lizards during the Early Cretaceous.
Topics: Amber; Animals; Biological Evolution; Fossils; Integumentary System; Lizards; Myanmar; Phylogeny; X-Ray Microtomography
PubMed: 35102237
DOI: 10.1038/s41598-022-05735-5 -
Integrative Organismal Biology (Oxford,... 2020Salamanders and newts (urodeles) are often used as a model system to elucidate the evolution of tetrapod locomotion. Studies range from detailed descriptions of...
Salamanders and newts (urodeles) are often used as a model system to elucidate the evolution of tetrapod locomotion. Studies range from detailed descriptions of musculoskeletal anatomy and segment kinematics, to bone loading mechanics and inferring central pattern generators. A further area of interest has been muscle activity patterns, measured through electromyography (EMG). However, most prior EMG work has primarily focused on muscles of the forelimb or hindlimb in specific species or the axial system in others. Here we present data on forelimb, hindlimb, and epaxial muscle activity patterns in one species, , during steady state walking. The data are calibrated to limb stride cycle events (stance phase, swing phase), allowing direct comparisons to homologous muscle activation patterns recorded for other walking tetrapods (e.g., lizards, alligators, turtles, mammals). Results demonstrate that has similar walking kinematics and muscle activity patterns to other urodele species, but that interspecies variation does exist. In the forelimb, both the and are active for 80% of the forelimb swing phase, while the is active at the swing-stance phase transition and continues through 86% of the stance phase. In the hindlimb, both the and are active for 30% of the hindlimb swing phase, while the is active 65% through the swing phase and remains active for most of the stance phase. With respect to the axial system, both the anterior and posterior display two activation bursts, a pattern consistent with stabilization and rotation of the pectoral and pelvic girdles. In support of previous assertions, comparison of muscle activity timings to other walking tetrapods revealed broad-scale similarities, potentially indicating conservation of some aspects of neuromuscular function across tetrapods. Our data provide the foundation for building and testing dynamic simulations of fire salamander locomotor biomechanics to better understand musculoskeletal function. They could also be applied to future musculoskeletal simulations of extinct species to explore the evolution of tetrapod locomotion across deep-time.
PubMed: 33791558
DOI: 10.1093/iob/obaa015 -
Journal of Morphology Oct 2019Living gars are a small clade of seven species that occupy an important position on the actinopterygian phylogenetic tree as members of Holostei, sister-group to...
Living gars are a small clade of seven species that occupy an important position on the actinopterygian phylogenetic tree as members of Holostei, sister-group to teleosts, and exhibit many plesiomorphic traits used to interpret and reconstruct early osteichthyan feeding mechanisms. Previous studies of gar feeding kinematics have focused on the ram-based, lateral-snapping mode of prey capture found in the narrow-snouted Lepisosteus genus, whereas this study focuses on a member of the broad-snouted Atractosteus sister-genus, the alligator gar (Atractosteus spatula, Lacépède, 1803). High-speed videography reveals that the feeding system of alligator gars is capable of rapid expansion from anterior to posterior, timed in a way to generate suction, counteract the effects of a bow-wave during ram-feeding, and direct a unidirectional flow of water through the feeding system. Reconstructed contrast-enhanced μCT-based cranial anatomy and three-dimensional modeling of linkage mechanics show that a lateral-sliding palatoquadrate, flexible intrasuspensorial joint, pivoting interhyal, and retractable pectoral girdle increase the range of motion and expansive capabilities of the alligator gar feeding mechanism. Reconstructions of muscular anatomy, inferences from in vivo kinematics, and in situ manipulations show that input from the hyoid constrictors and hypaxials play an important role in decoupling and modulating the dual roles of the sternohyoideus during feeding: hyoid retraction (jaw opening) and hyoid rotation (pharyngeal expansion). The alligator gar possesses an intricate feeding mechanism, capable of precise control with plesiomorphic muscles that represent one of the many ways the ancestral osteichthyan feeding mechanism has been modified for prey capture.
Topics: Animals; Biomechanical Phenomena; Eating; Feeding Behavior; Fishes; Hyoid Bone; Jaw; Muscles
PubMed: 31385619
DOI: 10.1002/jmor.21048