Shape Of Ossicles Research Articles

Ecomorphological correlates of inner and middle ear anatomy within phyllostomid bats.

Echolocation is the primary sense used by most bats to navigate their environment. However, the influence of echolocating behaviors upon the morphology of the auditory apparatus remains largely uninvestigated. While it is known that middle ear ossicle size scales positively with body mass across mammals, and that peak call frequency scales negatively with body mass among bats, there are still large gaps in our understanding of the degree to which allometry or ecology influences the morphology of the chiropteran auditory apparatus. To investigate this, we used μCT datasets to quantify three morphological components of the inner and middle ear: ossicle size, ossicle shape, and cochlear spirality. These data were collected across 27 phyllostomid species, spanning a broad range of body sizes, habitats, and dietary categories, and the relationships between these variables and ear morphology were assessed using a comparative phylogenetic approach. Ossicle size consistently scaled with strong negative allometry relative to body mass. Cochlear spirality was significantly (p=.025) associated with wing aspect ratio (a proxy for habitat use) but was not associated with body mass. From a morphological perspective, the malleus and incus exhibited some variation in kind with diet and call frequency, while stapes morphology is more closely tied to body size. Future work will assess these relationships within other chiropteran lineages, and investigate potential morphological differences in the middle and inner ear of echolocating-vs-non-echolocating taxa.

A morphological analysis of carnivoran ossicles from Rancho La Brea.

The morphology of the mammalian middle ear-including the size, shape, and stiffness of individual ossicles-controls their vibrational response to sound and, is closely related to an animal's auditory capabilities. While the relationship between middle ear morphology and hearing frequency has been explored in living carnivorans, the size and shape of ossicles in fossil carnivorans have been sparsely documented. In this study, we present the first morphological data on four iconic carnivoran taxa from the Rancho La Brea Tar Pits: Smilodon fatalis, Panthera atrox, Canis dirus, and Arctodus simus. These data are contextualized with samples of extant felids, canids, and ursids to determine the extent to which the ossicles of these iconic fossil taxa resemble their living relatives. Six, five, and seven linear measurements were taken from the malleus, incus, and stapes, respectively. Comparisons of geometric means reveal that the ossicles of fossil canids and felids are similar in size to living analogs, but those of A. simus are significantly larger than those of any living ursid. Further, principal components analyses demonstrate close morphological affinities between fossil and extant taxa within canids and felids, and again, a greater disparity between fossil and extant ursids. Canids and ursids occupy distinct regions of the morphospace, yet both overlap the morphological range spanned by felids. While some elements-for example, the stapes-require further specimens to facilitate more nuanced interpretations of variation, our findings underscore the need for concerted efforts towards identifying and preserving these bones within fossil assemblages.

Species Identification and Relationship of Sea Cucumber species from Pulau Tinggi and Sedili Kechil, Johor Based on Ossicle Shape

Sea cucumbers are an abundant echinoderm group in Malaysia which provides commercial and medicinal values to local people. Due to the lack of data on sea cucumbers status in Johor coastal seawaters, this study was conducted. This study aimed to identify the species and relationship of sea cucumber from two selected Johor coastal seawater; Pulau Tinggi and Sedili Kechil based on ossicle shape. The current study recorded 53 individuals of sea cucumbers, of which 23 individuals were from Pulau Tinggi, Mersing District and 30 individuals were from Sedili Kechil, Kota Tinggi District. A number of 10 species of sea cucumber were found in the coastal waters of Pulau Tinggi, Mersing and three species in Sedili Kechil, Kota Tinggi, Johor. A total of 10 ossicle shapes were observed and extracted from the sea cucumber samples namely button, perforated plate, table, C-shaped rod, rosette, anchor, spider, I-shaped rod, boomerang, and J-shaped rod. The species relationship based on ossicle shapes was analysed using clustering option of PAST (PAleontological STatistics) software version 4.03. The analysis concluded that two groups of sea cucumber families i.e. Holothuriidae and Stichopodidae were present, although S. chloronotus clustered closer with the members of family Holothuriidae. Although more specimens are required to generate better conclusive results, the outcomes provided updated data on sea cucumber species in Johor seawater.

Cucumaria fedotovi, a New Species of Holothurian (Holothuroidea, Dendrochirotida, Cucumariidae) from the Karaginskii Gulf, Bering Sea

A new species of dendrochirotid holothurian, Cucumaria fedotovi sp. nov. (Holothuroidea, Dendrochirotida, Cucumariidae), has been described in the Karaginskii Gulf, Bering Sea, Russia, from the depths of 31–34 m. The new species differs from the other species of the genus Cucumaria by the shape of ossicles of the body skin and by tube feets. The new species is characterized by ossicles in form of large lobed perforated plates with sharp teeth on the outer edge. In the tube feets, large, specific, laciniate, stellate plates predominate (up to ten rays), with numerous holes and sharp teeth along the outer edge.

Morphology, shape variation and movement of skeletal elements in starfish (Asterias rubens).

Starfish (order: Asteroidea) possess a complex endoskeleton composed of thousands of calcareous ossicles. These ossicles are embedded in a body wall mostly consisting of a complex collagen fiber array. The combination of soft and hard tissue provides a challenge for detailed morphological and histological studies. As a consequence, very little is known about the general biomechanics of echinoderm endoskeletons and the possible role of ossicle shape in enabling or limiting skeletal movements. In this study, we used high-resolution X-ray microscopy to investigate individual ossicle shape in unprecedented detail. Our results show the variation of ossicle shape within ossicles of marginal, reticular and carinal type. Based on these results we propose an additional classification to categorize ossicles not only by shape but also by function into 'connecting' and 'node' ossicles. We also used soft tissue staining with phosphotungstic acid successfully and were able to visualize the ossicle ultrastructure at 2-μm resolution. We also identified two new joint types in the aboral skeleton (groove-on-groove joint) and between adambulacral ossicles (ball-and-socket joint). To demonstrate the possibilities of micro-computed tomographic methods in analyzing the biomechanics of echinoderm skeletons we exemplarily quantified changes in ossicle orientation for a bent ray for ambulacral ossicles. This study provides a first step for future biomechanical studies focusing on the interaction of ossicles and soft tissues during ray movements.

Uncommon Ossicle in Holothuria (Mertensiothuria) Leucospilota from Teluk Nipah, Pangkor Island

The high popularity of a commercial sea cucumber species on Pangkor Island (i.e. Stichopus horrens) has resulted in a lack of studies on Holothuria (Mertensiothuria) leucospilota from Pangkor Island, Perak, Malaysia. S. horrens is the main ingredient of gamat-based traditional medicine on the resort island, while H. leucospilota is the most dominant species. For that reason, this study aimed to isolate ossicles from a specimen of morphospecies H. leucospilota collected from Teluk Nipah Beach, Pangkor Island; and to determine the shapes of the ossicles for species verification. A number of six ossicle shapes were observed. Beside buttons and tables as the common ossicle shapes; I-shaped rod, long I-shaped rod, branched rod, and spider-shaped rod were also documented. Nonetheless, the spider-shaped rod is an unusual ossicle shape in H. leucospilota as there was no previous record on it, thus it could be considered as a new finding. In summary, the results of this research indicate the uniqueness of the specimen of morphospecies H. leucospilota as a result of the presence of the spider-shaped rod. More studies with more samples, more morphological approaches as well as more molecular techniques need to be incorporated in future for a better insight.

Clinical significance and morphological analysis of the os subfibulare using radiologic assessment in patients with chronic lateral ankle instability

Category: Ankle Introduction/Purpose: Although os subfibulare has been associated to various clinical problems in patients with chronic lateral ankle instability (CLAI), there are a few studies on the analysis of morphological characteristics of os subfibulare. The purpose of this study is to analyze morphologic characteristics of the os subfibulare and to evaluate the clinical significance of the os subfibulare in patients with CLAI. Methods: Among 252 patients who visited our training hospital with the symptom of lateral ankle instability for more than 1 year after sustaining ankle injury, 71 patients with os subfibulare who underwent magnetic resonance imaging (MRI) of the ankle were included in this study. For each patient, the simple radiologic assessment was also performed. The shape and size of ossicles were measured on a sagittal MR images. The location of the subfibular ossicle was classified into 3 zones by relation with the attachment site of the anterior talofibular ligament. The talofibular impingement, in which ossicles impinged to the talar articular surface. Results: The most common shape of ossicles was oval, and the most common site of ossicles was ATFL attach site. 61% of patients showed talofibular joint impingement on axial MR images, whereas 28 cases showed normal congruency of the talofibular joint. Forty-eight cases in 71 patients with CLAI had an enlarged fibular shape instead of a contralateral fibula on simple radiographs. The age; sex; the shape, location, and size of the ossicle; talofibular articular impingement; and history of major trauma were associated with surgical treatment in statistical analysis. Conclusion: The morphological analysis of the os subfibulare revealed that the ossicle manifested radiographic differences based on its size, location, and morphology. Based on the findings of our study, we suggest it is crucial to understand the morphologeical characteristics of the os subfibulare in patients with CLAI and to establish the treatment plan accordingly.

Colour, confusion, and crossing: resolution of species problems inBohadschia(Echinodermata: Holothuroidea)

Sea cucumbers of the genus Bohadschia (Holothuroidea: Echinodermata) are among the larger and more common echinoderms on tropical coral reefs. While the genus is easy to identify and has been recognized for some time, the number and status of species have varied substantially for over a century. The species problem in Bohadschia is the result of high intra-specific variability and little inter-specific divergence in the principal, traditional taxonomic characters, the shape and size of microscopic dermal ossicles. We re-evaluate Bohadschia primarily based on colour pattern of living animals and mitochondrial sequence data. The character sets are congruent, and both cleanly delineate 11 species and one common hybrid form. The vexing Bohadschia marmorata complex is resolved into four species, all of which have available names, although two have not been recognized correctly since their description. A fairly common colour form intermediate between B. argus and B. vitiensis has mtDNA sequences matching either one or the other species and is interpreted as a hybrid form. Several species occur sympatrically at most locations; however, the most closely related species show evidence of allopatric divergence. Character state reconstructions suggest that the prevalent diurnal burrowing and nocturnal epibenthic feeding behaviour among Bohadschia evolved early in the history of the genus. Ossicle shape and size were found to perform poorly in distinguishing species, while colour pattern is diagnostic.

Realistic 3D Computer Model of the Gerbil Middle Ear, Featuring Accurate Morphology of Bone and Soft Tissue Structures

In order to improve realism in middle ear (ME) finite-element modeling (FEM), comprehensive and precise morphological data are needed. To date, micro-scale X-ray computed tomography (μCT) recordings have been used as geometric input data for FEM models of the ME ossicles. Previously, attempts were made to obtain these data on ME soft tissue structures as well. However, due to low X-ray absorption of soft tissue, quality of these images is limited. Another popular approach is using histological sections as data for 3D models, delivering high in-plane resolution for the sections, but the technique is destructive in nature and registration of the sections is difficult. We combine data from high-resolution μCT recordings with data from high-resolution orthogonal-plane fluorescence optical-sectioning microscopy (OPFOS), both obtained on the same gerbil specimen. State-of-the-art μCT delivers high-resolution data on the 3D shape of ossicles and other ME bony structures, while the OPFOS setup generates data of unprecedented quality both on bone and soft tissue ME structures. Each of these techniques is tomographic and non-destructive and delivers sets of automatically aligned virtual sections. The datasets coming from different techniques need to be registered with respect to each other. By combining both datasets, we obtain a complete high-resolution morphological model of all functional components in the gerbil ME. The resulting 3D model can be readily imported in FEM software and is made freely available to the research community. In this paper, we discuss the methods used, present the resulting merged model, and discuss the morphological properties of the soft tissue structures, such as muscles and ligaments.

A new species of deep-water Holothuroidea (Echinodermata) of the genus <i>Synallactes</i> from off western Mexico

An undescribed species of Synallactes was collected during a deep-water benthic fauna survey off the Pacific coast of Mexico in the East Pacific, with the R/V El Puma. This new species differs from all the other known Synallactes by the presence of huge massive rods in the tube feet, some of them club-shaped. The later ossicle shape is unique among Holothuroidea. This is the first record of a Synallactes in the Gulf of California.