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Proceedings. Biological Sciences Oct 1996The recent analysis of the homologies of the elements in the highly derived pectoral girdle of turtles is used as an example to clarify how character congruence tests...
The recent analysis of the homologies of the elements in the highly derived pectoral girdle of turtles is used as an example to clarify how character congruence tests conjectures of homology in cladistic analysis. Character congruence does not test alternative conjectures of similarity i.e. alternative character definitions and/or descriptions. It will only test the proposition that an observed relationship of similarity is homologous or not, and hence indicate whether this observed relationship of similarity may be parsimoniously explained by common ancestry, or must rather be treated as homoplasy. To test alternative hypotheses of homology, or alternative conjectures of similarity, the data matrix must be constructed such as to allow the evaluation of these alternatives on the basis of parsimony.
Topics: Animals; Biological Evolution; Genetic Variation; Turtles
PubMed: 8914335
DOI: 10.1098/rspb.1996.0204 -
Anatomy & Cell Biology Mar 2023Agenesis or congenital hypoplasia of skeletal muscles occurs infrequently but may occur with specific conditions such as Poland syndrome. The trapezius muscle can vary...
Agenesis or congenital hypoplasia of skeletal muscles occurs infrequently but may occur with specific conditions such as Poland syndrome. The trapezius muscle can vary in the extent of its bony attachments or may have additional slips, however congenital absence or hypoplasia is extremely rare. There are only a few reports of partial or complete absence of the trapezius muscle. Two cases of bilateral absence of the trapezius were both in males and were accompanied by the absence of additional muscle in the pectoral girdle. Herein, we describe a case of a 56-year-old male cadaver with bilateral hypoplasia of the trapezius. The muscle was largely represented by atrophied muscle fibers with an abundance of fibrotic or fatty connective tissue. This subject had very minor hypoplasia of the left pectoralis major muscle, but the remaining muscles of the pectoral girdle were normal. The spinal accessory nerve terminated in the sternocleidomastoid muscle on both sides, failing to reach the trapezius. We interpret these findings to be consistent with a minor variant of Poland syndrome.
PubMed: 36263506
DOI: 10.5115/acb.22.139 -
Developmental Dynamics : An Official... May 2011Genes expressed in the somatopleuric mesoderm, the embryonic domain giving rise to the vertebrate pelvis, appear important for pelvic girdle formation. Among such genes,...
Genes expressed in the somatopleuric mesoderm, the embryonic domain giving rise to the vertebrate pelvis, appear important for pelvic girdle formation. Among such genes, Pbx family members and Emx2 were found to genetically interact in hindlimb and pectoral girdle formation. Here, we generated compound mutant embryos carrying combinations of mutated alleles for Pbx1, Pbx2, and Pbx3, as well as Pbx1 and Emx2, to examine potential genetic interactions during pelvic development. Indeed, Pbx genes share overlapping functions and Pbx1 and Emx2 genetically interact in pelvic formation. We show that, in compound Pbx1;Pbx2 and Pbx1;Emx2 mutants, pelvic mesenchymal condensation is markedly perturbed, indicative of an upstream control by these homeoproteins. We establish that expression of Tbx15, Prrx1, and Pax1, among other genes involved in the specification and development of select pelvic structures, is altered in our compound mutants. Lastly, we identify potential Pbx1-Emx2-regulated enhancers for Tbx15, Prrx1, and Pax1, using bioinformatics analyses.
Topics: Animals; Computational Biology; Female; Gene Expression Regulation, Developmental; Homeodomain Proteins; In Situ Hybridization; Male; Mice; Paired Box Transcription Factors; Pelvis; Pre-B-Cell Leukemia Transcription Factor 1; Proto-Oncogene Proteins; T-Box Domain Proteins; Transcription Factors
PubMed: 21455939
DOI: 10.1002/dvdy.22617 -
Journal of Fish Biology Nov 2018A new species of Pimelodella is described from several right-bank tributaries of the Rio Madeira basin in Amazonas and Rondônia states, Brazil. The new species differs...
A new species of Pimelodella is described from several right-bank tributaries of the Rio Madeira basin in Amazonas and Rondônia states, Brazil. The new species differs from all congeners by the supraoccipital process not reaching the anterior nuchal plate, 43-45 total vertebrae, maxillary barbels reaching between adpressed anal-fin terminus and caudal-fin origin, epiphyseal branch of supraorbital laterosensory canal emerging as two distantly-positioned pores and a conspicuous black mark at distal third of dorsal fin, between dorsal-fin spine and third branched ray. A detailed description of the cephalic laterosensory system of the new species is provided and contrasted with other Siluriformes and Ostariophysi. A discussion regarding homology of the catfish upper pectoral girdle bones is offered in light of modifications of the postotic and supratemporal lateral-line canals. Based on the placement of the pterotic branch of the postotic canal, it is concluded that the extrascapula is fused to the pterotic in Siluriformes. Results presented herein offer an example of how lateral-line morphology can be used as a compelling source of evidence to help determine homology of cranial and upper pectoral girdle bones.
Topics: Animals; Brazil; Catfishes; Color; Skull; Species Specificity; Spine
PubMed: 30203470
DOI: 10.1111/jfb.13795 -
Frontiers in Zoology Jul 2010Theria (marsupials and placental mammals) are characterized by a highly mobile pectoral girdle in which the scapula has been shown to be an important propulsive element...
BACKGROUND
Theria (marsupials and placental mammals) are characterized by a highly mobile pectoral girdle in which the scapula has been shown to be an important propulsive element during locomotion. Shoulder function and kinematics are highly conservative during locomotion within quadrupedal therian mammals. In order to gain insight into the functional morphology and evolution of the pectoral girdle of the two-toed sloth we here analyze the anatomy and the three-dimensional (3D) pattern of shoulder kinematics during quadrupedal suspensory ('upside-down') locomotion.
METHODS
We use scientific rotoscoping, a new, non-invasive, markerless approach for x-ray reconstruction of moving morphology (XROMM), to quantify in vivo the 3D movements of all constituent skeletal elements of the shoulder girdle. Additionally we use histologic staining to analyze the configuration of the sterno-clavicular articulation (SCA).
RESULTS
Despite the inverse orientation of the body towards gravity, sloths display a 3D kinematic pattern and an orientation of the scapula relative to the thorax similar to pronograde claviculate mammalian species that differs from that of aclaviculate as well as brachiating mammals. Reduction of the relative length of the scapula alters its displacing effect on limb excursions. The configuration of the SCA maximizes mobility at this joint and demonstrates a tensile loading regime between thorax and limbs.
CONCLUSIONS
The morphological characteristics of the scapula and the SCA allow maximal mobility of the forelimb to facilitate effective locomotion within a discontinuous habitat. These evolutionary changes associated with the adoption of the suspensory posture emphasized humeral influence on forelimb motion, but allowed the retention of the plesiomorphic 3D kinematic pattern.
PubMed: 20619000
DOI: 10.1186/1742-9994-7-21 -
Journal of Morphology Aug 2023Mudskippers are a group of amphibious fishes in the family Oxudercidae, whose species inhabit a range of habitats from mostly aquatic to mostly terrestrial. Most of our...
Mudskippers are a group of amphibious fishes in the family Oxudercidae, whose species inhabit a range of habitats from mostly aquatic to mostly terrestrial. Most of our understanding about habitat preference comes from natural history observations, particularly where they are collected (i.e., low intertidal vs. high intertidal regions). Mudskippers have undergone several morphological changes to accommodate a terrestrial life, including major changes to the pectoral and pelvic girdles. These changes result in a novel crutching gait, which mudskippers use to move over land. Though the appendicular morphology and crutching gait of mudskippers have been described in some species, few studies have compared skeletal structures across the family. In our study, we use microcomputed tomography (µCT) scans to compare the skeletal anatomy of 16 species of aquatic and terrestrial mudskippers. Linear discriminant analysis is used to analyze measurements obtained through geometric morphometrics (landmarks). We found bone structures of the pectoral region in the terrestrial group were significantly longer and wider than those in the aquatic group. Furthermore, a significant difference in anatomy is shown between terrestrial and aquatic genera with both axial and appendicular elements contributing to the separation between groups. This work describes the differences in skeletal morphology associated with terrestriality in mudskippers and provides valuable insights into specific anatomical characteristics contributing to their adaptation to novel environments.
Topics: Animals; Animal Fins; X-Ray Microtomography; Ecosystem; Fishes
PubMed: 37458082
DOI: 10.1002/jmor.21612 -
Mymensingh Medical Journal : MMJ Jul 2023Having the first bone to ossify clavicle is a bone of pectoral girdle. It is the only bony attachment between the trunk and upper limb. To obtain the precise data that...
Having the first bone to ossify clavicle is a bone of pectoral girdle. It is the only bony attachment between the trunk and upper limb. To obtain the precise data that is required to investigate the range in size and morphological features of the human clavicle, a study was undertaken on dry human clavicles which had been sourced from the Department of Anatomy. The purpose for undertaking this study was to obtain baseline data on the clavicular bow in the transverse plane. This cross-sectional descriptive study having some analytical components was done among 150 (65 right and 85 left) fully ossified dry clavicles in Mymensingh Medical College, Bangladesh from January 2020 to December 2020. Sample which met the inclusion criteria was collected through non random sampling technique, from Anatomy department of Mymensingh Medical College and Community Based Medical College Bangladesh. The parameters (the depth of medial and lateral curvatures) were measured with the help of rigid osteometry board and were expressed in millimeter. In the current study, the mean±SD depth of medial curvature of 65 clavicles of right side was 15.54±3.54mm and 15.45±3.24mm of 85 left clavicles. The mean±SD depth of lateral curvature of right side was 11.71±2.54mm and of left side was 9.21±2.31mm. Correlation was done in between depth of medial and lateral curvatures on both sides and the regression line showed positive correlation but these differences were statistically non-significant on both sides.
Topics: Humans; Clavicle; Cross-Sectional Studies; Bangladesh; Universities
PubMed: 37391951
DOI: No ID Found -
Journal of Morphology Sep 1975A consideration of head development in two species of Esox, lucius and americanus (ssp. vermiculatus) representing the two subgenera Esox and Kenozoa respectively,...
A consideration of head development in two species of Esox, lucius and americanus (ssp. vermiculatus) representing the two subgenera Esox and Kenozoa respectively, focused on the significance of the variations of the latero-sensory canal system, its associated bones, and other skeletal elements. In living forms only aspects of "regression" or specialization can be studied. Canals tend to be reduced to pit lines first at their termini but can be broken in their course. Pit lines range from nearly canals to surface structures, or even fail to develop. The number of neuromasts varies. Canal bones develop from two centers: neuromast related and deeper membranous centers which may have no relationship to neuromasts. Tooth-bearing and non-canal-related dermal bones have only membranous (original) centers. The number of neuromasts associated with a bone usually does not affect its development or form. In the case of the circumorbital bones, the extrascapulars, and the nasal, a one to one relationship has developed by regression--towards the development of the latero-sensory component only. The idea that reductions in bone number are commonly traceable to fusion is rejected although examples of fusion are know. Most bones that disappear are simply lost (no blastema or other evidence of their presence seen in development). The relationship between dermal bone and chondral bone is examined and there is evidence of the former giving rise to the latter. The ontogenic order of appearances shows a feeding (functional) correlation.
Topics: Animals; Bone Development; Fishes; Sense Organs
PubMed: 1159792
DOI: 10.1002/jmor.1051470106 -
The Journal of the Acoustical Society... Dec 2023Sound production capabilities and characteristics in Loricariidae, the largest catfish family, have not been well examined. Sounds produced by three loricariid catfish...
Sound production capabilities and characteristics in Loricariidae, the largest catfish family, have not been well examined. Sounds produced by three loricariid catfish species, Otocinclus affinis, Pterygoplichthys gibbiceps, and Pterygoplichthys pardalis, were recorded. Each of these species produces pulses via pectoral-fin spine stridulation by rubbing the ridged condyle of the dorsal process of the pectoral-fin spine base against a matching groove-like socket in the pectoral girdle. Light and scanning electron microscopy were used to examine the dorsal process of the pectoral-fin spines of these species. Mean distances between dorsal process ridges of O. affinis, P. gibbiceps, and P. pardalis were 53, 161, and 329 μm, respectively. Stridulation sounds occurred during either abduction (type A) or adduction (type B). O. affinis produced sounds through adduction only and P. pardalis through abduction only, whereas P. gibbiceps often produced pulse trains alternating between abduction and adduction. In these species, dominant frequency was an inverse function of sound duration, fish total length, and inter-ridge distance on the dorsal process of the pectoral-fin spine and sound duration increased with fish total length. While stridulation sounds are used in many behavioral contexts in catfishes, the functional significance of sound production in Loricariidae is currently unknown.
Topics: Animals; Sound; Catfishes; Animal Communication; Body Size; Sound Spectrography
PubMed: 38059727
DOI: 10.1121/10.0022575 -
Developmental Biology Apr 2002Hox and Pax transcription factors are master regulators of skeletal and organ morphogenesis. Some skeletal malformations encountered in Hoxa5 mutants are shared by the...
Hox and Pax transcription factors are master regulators of skeletal and organ morphogenesis. Some skeletal malformations encountered in Hoxa5 mutants are shared by the undulated (un) mice, which bear a point mutation in the Pax1 gene. To investigate whether Hoxa5 and Pax1 act in common pathways during skeletal development, we analyzed Hoxa5;un compound mutants. Our genetic studies show that Hoxa5 and Pax1 cooperate in the vertebral patterning of the cervicothoracic transition region and in acromion morphogenesis. The dynamics of expression of Hoxa5 and Pax1 in the pectoral girdle region suggest that both genes function in a complementary fashion during acromion formation. Whereas Pax1 is required for the recruitment of acromion precursor cells, Hoxa5 may provide regional cues essential for the correct formation of the acromion by ensuring Pax1 expression at the proper time and position during morphogenesis of the pectoral girdle. Hoxa5 also has a distinctive role in specifying the fate of perichondrial and chondrogenic cell lineages in a Sox9-dependent way.
Topics: Animals; Animals, Newborn; Body Patterning; Bone Development; DNA-Binding Proteins; Gene Expression Regulation, Developmental; Genes, Homeobox; Homeodomain Proteins; Mice; Mice, Inbred C57BL; Morphogenesis; Muscle, Skeletal; Paired Box Transcription Factors; Phenotype; Phosphoproteins; Transcription Factors
PubMed: 11900462
DOI: 10.1006/dbio.2002.0596