Functional morphology of the temporal region in the Rhynchocephalia

2003 ◽  
Vol 40 (4) ◽  
pp. 589-607 ◽  
Author(s):  
Xiao-Chun Wu
Keyword(s):  
Functional Morphology ◽  
Common Ancestor ◽  
Lateral Side ◽  
Temporal Region ◽  
Anterior Portion ◽  
Primitive State ◽  
Bone Structures ◽  
Jaw Musculature

Study of the functional morphology of the temporal region of the Rhynchocephalia by means of the analysis of jaw musculature and bone structures in living lepidosaurians suggests that the streptostyly of the quadrate is a derived state in the Lepidosauria and that its origin may have been coupled with the loss of the M. pterygoideus atypicus. Further, this analysis supports the view that the retention of a fixed quadrate in early rhynchocephalians with an incomplete lower temporal bar may have been required for precise tooth occlusion and suggests that a solid lower temporal bar in later rhynchocephalians may have served as a brace to support the lateral side of the quadrate condyle and thus prevent it from twisting anteriorly rather than posteriorly during the jaw cycle. It is hypothesized that a common ancestor shared by the Rhynchocephalia and Squamata had a skull with an incomplete lower temporal bar but a rigid quadrate. It is also hypothesized that the presence of the anterior portion of the M. pterygoideus (MPT) is a primitive state, and that the size of the pterygoid flange may have been a good indicator of the presence of the anterior portion of the MPT in fossil reptiles. As in Sphenodon, if the mandible is able to move anteroposteriorly, it must retract first during the jaw cycle in those reptiles in which a pterygoid flange is retained.

Additional Dermal Ossifications in the Anuran Skull: Morphological Novelties or Archaic Elements?

2011 ◽  
Vol 4 (1) ◽  
pp. 17-27 ◽  
Author(s):  
Sergei V. Smirnov
Keyword(s):  
Common Ancestor ◽  
The State ◽  
Cranial Morphology ◽  
Anterior Portion ◽  
Bombina Orientalis ◽  
Common Event ◽  
Rostral Portion ◽  
Morphological Novelties ◽  
Dermal Bones

Examination of the cranial morphology in Bombina orientalis (Anura: Discoglossidae) revealed the occurrence of additional dermal bones lying: a) between the nasals and frontoparietals, b) between frontoparietals, and c) on the tectum synoticum behind the frontoparietals. The presence of similar bones as well as extra ossifications lying in the midline in the rostral portion of skull was shown to be a rather common event among anurans. Based on the occurrence of bones with similar topology in crossopterygians and different stegocephalians, it was concluded that extra ossifications sporadically appearing in anurans are more likely to be ancient cranial elements than neomorphs. Additional dermal bones found in the anterior portion of the anuran skull are homologous to the postrostrals of crossopterygians; extra ossifications lying between the frontoparietals correspond to the bones with similar topology sporadically appearing in crossopterygians and stegocephalians; and extra bones situated behind the frontoparietals are homologous to the lateral extrascapulars (postparietals of stegocephalians) and the median extrascapular of crossopterygians. These extra bones were proposed to be inherited from the presumed common ancestor of all Gnathostomes and retained in anurans in the state of latent capacities. The sporadic appearance of these bones in anurans results from the phenotypical realization of these latent capacities.

BEETLES THAT CANNOT BITE: FUNCTIONAL MORPHOLOGY OF THE HEAD OF ADULT RHYSODINES (COLEOPTERA: CARABIDAE OR RHYSODIDAE)

1994 ◽  
Vol 126 (3) ◽  
pp. 667-672 ◽  
Author(s):  
Ross T. Bell
Keyword(s):  
Functional Morphology ◽  
The Other ◽  
Internal Cavity ◽  
Wood Fibers ◽  
Slime Molds ◽  
Food Items ◽  
Jaw Musculature

AbstractIn Rhysodini the greatly enlarged mentum forms the entering edge as the beetle wedge-pushes its way through wood. The mandibles cannot bite either wood fibers or food items, but function as a cover for the other mouthparts. The palpi are completely retractile. Each maxilla bears two stylets, the galea and lacinia, and the ligula consists of two bilobed structures. These are apparently the sole feeding structures enabling the beetles to prey on the amoeboid stage of slime molds. The large internal cavity of the head is interpreted as a compromise between a greatly reduced head volume, resulting from reduced jaw musculature, and the need to retain the surface of a full-sized head as part of the wedge-pushing apparatus.

Functional morphology of the esophagus of the tropical house gecko Hemidactylus mabouia (Squamata: Gekkonidae)

2015 ◽  
Vol 65 (2) ◽  
pp. 177-191
Author(s):  
Sirlene Souza Rodrigues-Sartori ◽  
Katiane de Oliveira Pinto Coelho Nogueira ◽  
Vinícius Albano Araújo ◽  
Clóvis Andrade Neves
Keyword(s):  
Functional Morphology ◽  
Food Habits ◽  
Endocrine Cells ◽  
Esophageal Mucosa ◽  
Anterior Portion ◽  
Argyrophil Cells ◽  
Morphological Studies ◽  
Ciliary Action ◽  
Acid Mucins ◽  
Hemidactylus Mabouia

In order to understand the biology of species that easily establish themselves in new environments, morphological studies are essential. This study aimed to describe the esophageal functional morphology ofHemidactylus mabouia, indicating adaptations to food habits. Seventeen adult specimens were used for anatomical, topological, histological, and histochemical analyses. Histological sections were stained with toluidine blue or submitted to techniques for identification of argyrophil and argentaffin endocrine cells, proteins, and glycoconjugates. The esophagus ofH. mabouiais a tubular straight-lined organ, and its anterior portion is dilated, facilitating the swallowing of whole prey. The esophageal epithelium is pseudostratified, containing cells secreting neutral and acid mucins. At the esophagogastric transition, we found a mixture of this epithelium with a simple prismatic epithelium secreting neutral mucins. The esophagus lamina propria is thin and non-glandular. At the esophagogastric transition it becomes thick and filled by branched simple acinous glands, with cells secreting neutral mucins, zymogenic cells, and argentaffin endocrine cells, with no argyrophil cells. The mucins protect the esophageal mucosa and lubricate the channel to facilitate the passage of food, while pepsinogen in the stomach increases the levels of pepsin for proteolytic digestion. The muscular tunica is made up of smooth muscle cells. Ciliary action, in addition to muscle contractions, facilitates the swallowing of small prey.

Microsurgical Approaches to the Medial Temporal Region: An Anatomical Study

2006 ◽  
Vol 59 (suppl_4) ◽  
pp. ONS-279-ONS-308 ◽  
Author(s):  
Alvaro Campero ◽  
Gustavo Tro´ccoli ◽  
Carolina Martins ◽  
Juan C. Fernandez-Miranda ◽  
Alexandre Yasuda ◽  
...  
Keyword(s):  
Anatomical Study ◽  
Middle Part ◽  
Surgical Anatomy ◽  
Surgical Approaches ◽  
Temporal Region ◽  
Anterior Portion ◽  
Posterior Portion ◽  
Medial Surface ◽  
Posterior Group ◽  
Quadrigeminal Plate

Abstract OBJECTIVE: To describe the surgical anatomy of the anterior, middle, and posterior portions of the medial temporal region and to present an anatomic-based classification of the approaches to this area. METHODS: Twenty formalin-fixed, adult cadaveric specimens were studied. Ten brains provided measurements to compare different surgical strategies. Approaches were demonstrated using 10 silicon-injected cadaveric heads. Surgical cases were used to illustrate the results by the different approaches. Transverse lines at the level of the inferior choroidal point and quadrigeminal plate were used to divide the medial temporal region into anterior, middle, and posterior portions. Surgical approaches to the medial temporal region were classified into four groups: superior, lateral, basal, and medial, based on the surface of the lobe through which the approach was directed. The approaches through the medial group were subdivided further into an anterior approach, the transsylvian transcisternal approach, and two posterior approaches, the occipital interhemispheric and supracerebellar transtentorial approaches. @@RESULTS:@@ The anterior portion of the medial temporal region can be reached through the superior, lateral, and basal surfaces of the lobe and the anterior variant of the approach through the medial surface. The posterior group of approaches directed through the medial surface are useful for lesions located in the posterior portion. The middle part of the medial temporal region is the most challenging area to expose, where the approach must be tailored according to the nature of the lesion and its extension to other medial temporal areas. CONCLUSION: Each approach to medial temporal lesions has technical or functional drawbacks that should be considered when selecting a surgical treatment for a given patient. Dividing the medial temporal region into smaller areas allows for a more precise analysis, not only of the expected anatomic relationships, but also of the possible choices for the safe resection of the lesion. The systematization used here also provides the basis for selection of a combination of approaches.

scholarly journals Anterior temporal lobe morphometry predicts categorization ability

2017 ◽  
Author(s):  
B. Garcin ◽  
M. Urbanski ◽  
M. Thiebaut De Schotten ◽  
R. Levy ◽  
E. Volle
Keyword(s):  
White Matter ◽  
Temporal Lobe ◽  
Temporal Region ◽  
List Type ◽  
Semantic Matching ◽  
Anterior Temporal Lobe ◽  
Anterior Portion ◽  
Semantic Categorization ◽  
The Right ◽  
Shape Categorization

AbstractCategorization is the mental operation by which the brain classifies objects and events. It is classically assessed using semantic and non-semantic matching or sorting tasks. These tasks show a high variability in performance across healthy controls and the cerebral bases supporting this variability remain unknown. In this study we performed a voxel-based morphometry study to explore the relationships between semantic and shape categorization tasks and brain morphometric differences in 50 controls. We found significant correlation between categorization performance and the volume of the grey matter in the right anterior middle and inferior temporal gyri. Semantic categorization tasks were associated with more rostral temporal regions than shape categorization tasks. A significant relationship was also shown between white matter volume in the right temporal lobe and performance in the semantic tasks. Tractography revealed that this white matter region involved several projection and association fibers, including the arcuate fasciculus, inferior fronto-occipital fasciculus, uncinate fasciculus, and inferior longitudinal fasciculus. These results suggest that categorization abilities are supported by the anterior portion of the right temporal lobe and its interaction with other areas.HighlightsAnterior temporal lobe morphometry correlates with categorization performancesSemantic is associated with a more rostral temporal region than shape categorizationSemantic categorization performances are associated with right temporal connections

scholarly journals The TMJ disc is a common ancestral feature in all mammals, as evidenced by the presence of a rudimentary disc during monotreme development

2020 ◽  
Author(s):  
Neal Anthwal ◽  
Abigail S Tucker
Keyword(s):  
Common Ancestor ◽  
Mandibular Condyle ◽  
Last Common Ancestor ◽  
The Novel ◽  
Developmental Anatomy ◽  
Baleen Whales ◽  
Mouse Mutants ◽  
Tmj Disc ◽  
Jaw Joint ◽  
Jaw Musculature

AbstractThe novel mammalian jaw joint, known in humans as the temporomandibular joint or TMJ, is cushioned by a fibrocartilage disc. This disc is secondarily absent in therian mammals that have lost their dentition, such as giant anteaters and some baleen whales. The disc is also absent in all monotremes. However, it is not known if the absence in monotremes is secondary to the loss of dentition, or if it is an ancestral absence. We use museum held platypus and echidna histological sections to demonstrate that the developing monotreme jaw joint forms a disc primordium that fails to mature and become separated from the mandibular condyle. We then show that monotreme developmental anatomy is similar to that observed in transgenic mouse mutants with reduced musculature. We therefore suggest that the absence of the disc on monotremes is a consequence of the changes in jaw musculature associated with the loss of adult teeth. Taken together, these data indicate that the ancestors of extant monotremes likely had a jaw joint disc, and that the disc evolved in the last common ancestor or all mammals.

A new species of Bananogmius (Teleostei: Tselfatiformes) from the Upper Cretaceous Carlile Shale of western Kansas

1999 ◽  
Vol 73 (3) ◽  
pp. 504-511 ◽  
Author(s):  
Christopher Fielitz ◽  
Kenshu Shimada
Keyword(s):  
New Species ◽  
Upper Cretaceous ◽  
Narrow Band ◽  
Lateral Side ◽  
Post Mortem ◽  
Anterior Portion ◽  
Shale Formation ◽  
A New Species

A new species, Bananogmius ellisensis n. sp., known only from the holotype, is described from the Blue Hill Shale Member (Upper Cretaceous, middle Middle Turonian) of the Carlile Shale Formation in western Kansas. The skull and anterior portion of the specimen is well-preserved and was subjected to little post-mortem deformation suggesting rapid burial. The nearly complete skull shows three characters that separate the fish from other species of Bananogmius: a straight, rather than ventrally curved dentary, a narrow band of teeth on the dentary that does not extend onto its lateral side, and a cylindrically-shaped articular condyle of the quadrate. The uncompressed preservation of the skull reveals a pair of long structures ventral to the mandible that are also found, but not described for some other Bananogmius species. Based on the positions of muscles in extant teleosts, these structures are most likely the mineralized protractor hyoidei muscles. Furthermore, these structures may be homologous with ventral structures found in Tselfatia. The presence of Bananogmius adds a new ecological component to the Blue Hill Shale fauna.

Post-radiation Bone Lesions in Mammary Cancer

1966 ◽  
Vol 52 (6) ◽  
pp. 401-420 ◽  
Author(s):  
Angelo Lattuada ◽  
Aldo Severini
Keyword(s):  
Bone Repair ◽  
Rib Fractures ◽  
Point Of View ◽  
The Other ◽  
Thoracic Wall ◽  
Bone Lesions ◽  
Anterior Portion ◽  
Dose Time ◽  
Post Radiation ◽  
Bone Structures

The radiographic patterns of post-radiation bone lesions in eight patients treated for breast cancer are described. Rib fractures - often multiple - at the anterior portion of the rib were observed in all patients. Two of them showed also lesions of the shoulder-blade, with a lesion in the humeral diaphysis in one. Only some of the eight patients have been heavily irradiated as far as the total dose, the diameter of the fields and the dose-time is concerned. In these cases the lesions were more severe and large in comparison to the other patients. Bone repair and reconstruction were not observed even after many years from initial treatment. Areas of overdosage at the level of bone structures may have occurred also in the other cases, where the usual therapeutical limits had not been overcome. This overdosage is likely to be due to the particular geometric relationships between neoplastic foci and thoracic wall, requiring several irradiation fields. From the radiographic point of view rib fractures are difficult to detect in their earlier phase; therefore the differential diagnosis has to be made with traumatic fractures. Later their recognition becomes easier though occasionally the problem of a differentiation from possible metastatic foci may arise.

Cranial morphology of the Loxommatidae (Amphibia: Labyrinthodontia)

1977 ◽  
Vol 280 (971) ◽  
pp. 29-101 ◽  
Keyword(s):  
Functional Morphology ◽  
Cranial Morphology ◽  
Additional Material ◽  
Jaw Muscles ◽  
Skull Shape ◽  
New Family ◽  
The Family ◽  
Basal Articulation ◽  
First Time ◽  
Jaw Musculature

The labyrinthodont superfamily Loxommatoidea is now divided into two families. The highly aberrant Spathicephalus is placed in a new family, the Spathicephalidae, to be described elsewhere. The family Loxommatidae is retained for the remaining genera, Loxomma, Megalocephalus and Baphetes . Additional material and further preparation has made possible a redescription of the three loxommatid genera and new skull restorations have been produced for most species. In particular the loxommatid braincase and palatoquadrate are reconstructed for the first time; in many features their structure is more primitive than that hitherto described for any temnospondyl. Since an intertemporal bone is found to be a feature of Baphetes as well as Loxomma , these two genera have been separated on the basis of skull shape and on stratigraphical grounds. A specimen from the Communis zone, Westphalian A, is attributed to Loxomma , as L. rankini sp.nov., while ‘ Loxomma bohemicum ’ has been transferred to the genus Baphetes as B. bohemicus (Fritsch). A further specimen, originally associated with Macrerpeton , has also been referred to this genus as B. lintonensis sp.nov. The skull of Megalocephalus pachycephalus can be described in greater detail than that of any other loxommatid species and thus forms the basis for discussion of the functional morphology. Jaw muscles are reconstructed for this species and it is concluded that the antorbital vacuity, which characterizes the Loxommatoidea, evolved as a bulging hole for a large pterygoideus muscle associated with a piscivorous habit and a kinetic inertial system of jaw closure. Consideration of the mechanics of jaw closure sheds light on a further enigma, i.e. the function of the basipterygoid articulation in the primitive temnospondyl skull. The loxommatid skull is considered divisible into two units. The presence of a specialized cranial joint between the quadrate and quadratojugal allows potential for any movement at the basal articulation to be accommodated in the main at this site. It is suggested that the system described for loxommatids represents an alternative design to the mobile cheek region of anthracosaurs and that the articulations represent zones of elasticity, which accommodate the stresses on the skull caused by a powerful jaw musculature.

scholarly journals The anatomy of Meyer's loop revisited: changing the anatomical paradigm of the temporal loop based on evidence from fiber microdissection

2015 ◽  
Vol 122 (6) ◽  
pp. 1253-1262 ◽  
Author(s):  
Cristina Goga ◽  
Uğur Türe
Keyword(s):  
Internal Capsule ◽  
Temporal Region ◽  
Optic Radiation ◽  
Anterior Portion ◽  
Anterior Extension ◽  
Fiber Dissection ◽  
Dissection Technique ◽  
Meyer’S Loop ◽  
Human Brains ◽  
Formalin Fixed

OBJECT The goal in this study was to explore and further refine comprehension of the anatomical features of the temporal loop, known as Meyer's loop. METHODS The lateral and inferior aspects of 20 previously frozen, formalin-fixed human brains were dissected under the operating microscope by using fiber microdissection. RESULTS A loop of the fibers in the anterior temporal region was clearly demonstrated in all dissections. This temporal loop, or Meyer's loop, is commonly known as the anterior portion of the optic radiation. Fiber microdissection in this study, however, revealed that various projection fibers that emerge from the sublentiform portion of the internal capsule (IC-SL), which are the temporopontine fibers, occipitopontine fibers, and the posterior thalamic peduncle (which includes the optic radiation), participate in this temporal loop and become a part of the sagittal stratum. No individual optic radiation fibers could be differentiated in the temporal loop. The dissections also disclosed that the anterior extension and angulation of the temporal loop vary significantly. CONCLUSIONS The fiber microdissection technique provides clear evidence that a loop in the anterior temporal region exists, but that this temporal loop is not formed exclusively by the optic radiation. Various projection fibers of the IC-SL, of which the optic radiation is only one of the several components, display this common course. The inherent limitations of the fiber dissection technique preclude accurate differentiation among individual fibers of the temporal loop, such as the optic radiation fibers.

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