scholarly journals Remarks on Correlations and Implications of the Mandibular Structure and Diet in Some Seals (Mammalia, Phocidae)

2014 ◽  
Vol 48 (3) ◽  
pp. 255-268 ◽  
Author(s):  
I.A. Koretsky ◽  
S.J. Rahmat ◽  
N. Peters
Keyword(s):  
Mandibular Ramus ◽  
Morphological Examination ◽  
Dietary Preference ◽  
Angle Function ◽  
The Family ◽  
Condyloid Process ◽  
Size Ofthe ◽  
Mandibular Morphology ◽  
Process Measurements ◽  
Muscles Of Mastication

Abstract Remarks on Correlations and Implications of the Mandibular Structure and Diet in Some Seals (Mammalia, Phocidae). Koretsky, I. A., Rahmat, S. J., Peters, N. — The diverse representatives of Recent seals within the three extant subfamilies (Cystophorinae, Phocinae, Monachinae) of the family Phocidae exhibit dietary variations among species, feeding on invertebrates and a diversity of prey depending on the season and availability. To explain this variability, an introductory morphological examination of the mandibular structure of Recent seals from each subfamily was performed, focusing on: heights of the mandibular ramus and condyloid process; measurements of the masseteric fossa; and attachments of muscles of mastication. After measuring the condyloid angles (the inclination of the condyloid process in relation to the axis of the alveolar row) among the examined species, a correlation between the size ofthe angle, function, and diet was recognized. Seals with a tall mandibular ramus and greater condyloid angle (Cystophorinae) feed on larger-sized prey, while seals with a shorter ramus and lesser condyloid angle feed on small (Monachinae) to medium-sized (Phocinae) prey, regardless of the overall size of the seal. This study focused on the mandibular morphology of some living and fossil representatives of Phocidae, providing an association between functional and ecological interpretations of modern seals in general and extrapolating this knowledge for fossil dietary preference.

MATHEMATICAL MODEL AND AREA OF EXISTENCE OF THE FAMILY CRANKS AND MOBILE MECHANISMS WITH THE MAXIMUM TRANSMISSION ANGLE

2020 ◽  
pp. 20-26
Author(s):  
N. A. Sereda
Keyword(s):  
Mathematical Model ◽  
New Family ◽  
Arm Span ◽  
Angle Function ◽  
Straight Line ◽  
Transmission Angle ◽  
Crank Angle ◽  
The Family ◽  
Unit Radius ◽  
Maximum Transmission

The article examines crank-rocker mechanisms. Such mechanisms are used in transport and technological machines. The article is devoted to the search for a new family of crank-rocker mechanisms. A mathematical model of a new family of crank-rocker mechanisms is obtained. In this family, the maximum transmission angle reaches 90 when the crank angle is 75. Thus, the new family of crank-rocker mechanisms differs from the known families by the position of the mechanism in which the maximum of the transmission angle function takes place. It is shown that, with a certain ratio of link lengths, the new family corresponds to the known families KKM-5 and KKM-7. The area of existence of a new family of crank-rocker mechanisms is established. This area is bounded by the arc of the circle of the unit radius and the curve. The mentioned curve is based on a joint solution of a mathematical model of a new family of mechanisms and the famous Kolchin straight line. The dependence for the minimum transmission angle is obtained. A formula for determining the angle of the rocker arm span is proposed. A graphical interpretation of the mentioned dependencies and formulas is constructed. The scope of existence of a new family of crank-rocker mechanisms and graphical interpretations are used in determining the geometric parameters of mechanisms. These mechanisms are part of a new family of mechanisms.

The enigmatic bivalve genus Paramya (Myoidea: Myidae): symbiotic association of an East Asian species with spoon worms (Echiura) and its transfer to the family Basterotiidae (Galeommatoidea)

2016 ◽  
Vol 97 (7) ◽  
pp. 1447-1454 ◽  
Author(s):  
Ryutaro Goto ◽  
Hiroshi Ishikawa ◽  
Yoichi Hamamura
Keyword(s):  
Coastal Waters ◽  
East Asian ◽  
Shell Morphology ◽  
The Other ◽  
Phylogenetic Position ◽  
Symbiotic Association ◽  
Morphological Examination ◽  
The Family ◽  
The Seto Inland Sea ◽  
Molecular Phylogenetic

Paramya is an enigmatic genus of Myidae (Bivalvia: Heterodonta: Myoidea) that includes three uncommon species: Paramya subovata (Conrad, 1845), Paramya recluzi (A. Adams, 1864) and Paramya africana Cosel, 1995. Paramya subovata is known as a commensal living in the burrow of the spoon worm Thalassema hartmani Fisher, 1947 (Annelida: Echiura: Thalassematidae), in North American coastal waters. However, the biology of the other two species remains unknown. In this study, we found P. recluzi living in the burrows of the two thalassematid echiuran species, Ikedosoma gogoshimense (Ikeda, 1904) and Arhynchite hayaoi Tanaka & Nishikawa, 2013, in intertidal flats in the Seto Inland Sea, Japan. Paramya recluzi was embedded in the burrow wall with its short siphons protruding into the host burrow lumen for respiration and filter feeding. To determine the phylogenetic position of P. recluzi, we performed a molecular phylogenetic analysis using the 18S, 28S, COI and H3 genes. Molecular analysis showed that P. recluzi belongs not to the family Myidae, but to the genus Basterotia (Galeommatoidea: Basterotiidae). Morphological examination of P. recluzi revealed that this species has many similarities with Basterotia (e.g. a single cardinal tooth on each valve and short siphons surrounded by tentacles). Thus, we propose that this species should be transferred from the genus Paramya to Basterotia. In addition, we also suggest that the other two species of Paramya (P. subovata and P. africana) should be transferred to the family Basterotiidae based on their shell morphology, anatomy and ecological characteristics.

scholarly journals Diversity Of Mandibular Morphology In Some Carnivorans

2015 ◽  
Vol 49 (3) ◽  
pp. 267-284 ◽  
Author(s):  
S. J. Rahmat ◽  
I. A. Koretsky
Keyword(s):  
General Pattern ◽  
Elephant Seal ◽  
Northern Elephant Seal ◽  
Feeding Mechanism ◽  
Small Prey ◽  
Diving Depth ◽  
Feeding Niche ◽  
Condyloid Process ◽  
Feeding Methods ◽  
Mandibular Morphology

Abstract Comparison of mandibular morphology of some aquatic (seals, walruses, and sea otters) and terrestrial (hyenas and pandas) carnivorans demonstrates a rather general pattern correlating size of condyloid angle, size of gape, and diet. Structural differences of carnivoran jaws reveal morphological and ecological adaptations that are directly correlated with availability of prey, diving depth, feeding competition and specialized feeding methods. Specifically, the inclination of the condyloid process relative to the axis of the alveolar row (= condyloid angle) can be used to determine dietary preferences, including size of prey. Generally, carnivorans with a large condyloid angle feed on larger prey, while a low condyloid angle suggests feeding on small prey or can be an advantageous feeding mechanism. Mirounga angustirostris (Northern elephant seal) displays sex-specific characters in cranial and postcranial elements. Likewise, significant sexually dimorphic differences in the size of condyloid angle imply that deeper-diving male Northern elephant seals have a feeding niche dissimilar to that of females. Morphological assessment of male M. angustirostris suggests they are bottom-feeding seals that utilize a suction-feeding mechanism to capture small prey and crush shells with their teeth, which become weaker as they age.

Morphological and Biochemical Systematics of Australian Freashwater and Estuarine Percichthyid Fishes

1978 ◽  
Vol 29 (5) ◽  
pp. 667 ◽  
Author(s):  
CM MacDonald
Keyword(s):  
Significant Variation ◽  
Electrophoretic Analysis ◽  
Morphological Examination ◽  
Fresh Waters ◽  
Australian Species ◽  
Protein Variation ◽  
Morphological Studies ◽  
The Family ◽  
Single Genus ◽  
Using Data

The taxonomy and evolutionary relationships of six Australian species of the family Percichthyidae have been investigated using data obtained from comparative morphological examination of preserved specimens and from electrophoretic detection of variation in proteins extracted from liver tissue. Members of the genera Maccullochella, Plectroplites, Macquaria and Percalates form a group of generalized percoid species that have presumably colonized Australian fresh waters from marine origins. On morphological grounds the group is here considered to belong in the basal percoid family Percichthyidae rather than in the specialized family Serranidae to which it has been previously assigned. Some doubt remains, however, as to the affinities of the genus Maccullochella. Evidence from morphological studies, and from electrophoretic analysis of protein variation at 19 genetic loci, indicates that Maccullochella differs extensively from the other genera and that the two subgroups so formed represent separate invasions of fresh waters by already distinct marine ancestors. The Australian genera Plectroplites, Macquaria and Percalates form a closely related monophyletic group which can be assigned to a single genus. The oldest available name for such a genus is Macquavia Cuvier and Valenciennes, 1830. Morphological and electrophoretic evidence supports the distinction of two species of Maccullochella, but no significant variation was detected between Percalates specimens initially identified as either P. colonorum or P. novemaculeatus.

scholarly journals New psychropotid species (Echinodermata Holothuroidea Elasipodida) of the Western Pacific with phylogenetic analyses

2021 ◽  
Author(s):  
Chuan Yu ◽  
Dongsheng Zhang ◽  
Ruiyan Zhang ◽  
Chunsheng Wang
Keyword(s):  
Phylogenetic Analysis ◽  
New Species ◽  
Deep Sea ◽  
Phylogenetic Analyses ◽  
The Other ◽  
Western Pacific ◽  
Morphological Examination ◽  
The Family ◽  
The Western Pacific ◽  
A New Species

Holothurians of the family Psychropotidae are widely distributed, but remain least studied deep-sea holothurians. On an expedition in the Western Pacific, six psychropotid specimens were collected by the Jiaolong human operated vehicle (HOV). Through morphological examination, four of them were identified as a new species, Benthodytes jiaolongi sp. nov., which was characterized as having minute papillae, narrow brims, and terminal anus; the ossicles were either rods or primary crosses. The remaining two specimens were identified as Psychropotes verrucicaudatus Xiao, Gong, Kou & Li, 2019, which was first recorded at the Kyushu-Palau Ridge. The phylogenetic analysis confirmed the classification status of B. jiaolongi and P. verrucicaudatus, and indicated a paraphyletic relationship within the genus Benthodytes. The new species clustered with Benthodytes sanguinolenta and was separated from the clade containing the other Benthodytes species.

scholarly journals Familial inheritance of TMD: a case report

2017 ◽  
Vol 5 (1) ◽  
Author(s):  
Maria Genello
Keyword(s):  
Mandibular Condyle ◽  
Normal Structure ◽  
The Body ◽  
Genetic Component ◽  
Contributing Factors ◽  
Dental Practitioners ◽  
The Family ◽  
Familial Inheritance ◽  
Risk Patients ◽  
Muscles Of Mastication

The TMJ is a joint that can perform both hinge and sliding motions and whose proper functioning depends on the actions of the joint and joint capsule, the muscles of mastication, and the condition and action of the mandibular condyle. If any of these components deviate from their normal structure or function, then TMD can result. There have been many reported contributing factors to TMD development, many of which include environmental influences such as bruxism, trauma, and other oral habits. However, a genetic component can also play a role. This paper reports a case of TMD occurring within three consecutive generations of a family and explores the possibility of this disorder exhibiting familial inheritance. Members of the family affected all displayed manifestations of joint laxity in other areas of the body, migraines, pain, and had smaller craniofacial dimensions with a narrower mandible. These factors were found to have a genetic influence and these genes can also be tied to TMD, thus supporting the argument that the cases of TMD seen in this family are in fact due to inheritance. If TMD can be shown to have a genetic component and be inherited, then dental practitioners would be able to identify high risk patients and help to modify environmental factors early on in order to help prevent the onset of TMD in those individuals.

scholarly journals STUDY OF THE SIZE OF THE CORONOID PROCESS OF MANDIBULE

2019 ◽  
Vol 34 (4) ◽  
pp. 811-815
Author(s):  
Svetlana Jovevska ◽  
Sanja Baldzieva
Keyword(s):  
Muscle Growth ◽  
Coronoid Process ◽  
Condyloid Process ◽  
Forensic Scientists ◽  
The Right ◽  
Pterygoid Muscles ◽  
Muscles Of Mastication ◽  
Functional Stress ◽  
Age And Sex ◽  
Important Structure

The mandible serves as an important structure in relation to mastication as all the muscles of mastication are attached to it. The Coronoid process is the anterior bony projected part of ramus of mandible giving attachment to two important muscles of mastication. The aim of our study was to observe the variation in the size of coronoid process in relation to its side (laterality), shape, age and sex. The material for this study comprised of 80 (160 sides) dry human mandibles. The age and sex differentiating criteria were detailed in materials and methods. The size of coronoid process was found to be approximately 1.5 mm longer on the right side than on the left side; 0.01 mm longer in males than females and 0.01 mm longer in dentulous than in edentulous. Triangular coronoid process was found to be the longest followed by round and then hook shaped. Male hormonal impact on muscle growth, bone remodeling and psychology probably lead to enhanced functional stress on mandible due to mastication as compared to that in females. Pterygoid muscles are involved mainly in side to side movement and Masseter-Temporalis (M-T) component in the robust vertical thrust during mastication for crushing. The condyloid process is for pterygoid and M-T-Coronoid Lever complex engenders the proportionate sexual dimorphism as observed in this study. Poor crushing activity in the edentulous is also corroborated in our observation.This comparative study is a pioneer study which will be beneficial for the Anthropologists, Forensic scientists and Reconstructive surgeons.

Mandibular Morphology in Complete Unilateral Cleft Lip and Palate

2004 ◽  
Vol 41 (4) ◽  
pp. 403-409 ◽  
Author(s):  
Gwen Swennen ◽  
Johannes-Ludwig Berten ◽  
Franz-Josef Kramer ◽  
Chantal Malevez ◽  
Albert De Mey ◽  
...  
Keyword(s):  
Cleft Lip ◽  
Cleft Lip And Palate ◽  
Spatial Position ◽  
Control Group ◽  
Mandibular Ramus ◽  
Treatment Protocols ◽  
Palate Repair ◽  
Mandibular Morphology ◽  
Post Hoc ◽  
Comparison Data

Objective The purpose of this study was to evaluate and compare mandibular morphology and spatial position in children with complete unilateral cleft lip and palate (UCLP) treated at two different cleft centers (Hannover and Brussels) following different surgical treatment protocols. Patients A total of 62 Caucasian children (40 boys, 22 girls) with nonsyndromic complete unilateral cleft lip and palate (UCLP) were evaluated by means of conventional cephalometric analysis at approximately the age of 10 years. Data of both cleft groups were compared with a control, noncleft group (n = 40) matched according to age and sex. Interventions The Hannover children with cleft (n = 36) underwent lip repair at a mean age of 5.83 ± 1.16 months. The hard and soft palates were closed at a mean age of 29.08 ± 4.68 and 32.25 ± 4.29 months, respectively. The Brussels children with cleft (n = 26) were treated according to the Malek surgical protocol with soft palate repair at a mean age of 3.04 ± 0.20 months and simultaneous lip and hard palate repair at a mean age of 6.15 ± 0.68 months. Results Statistical analysis (analysis of variance with post hoc Tukey's test) showed a significant (p = .001) smaller mandibular ramus length (Co-Go) in the Brussels cleft group, compared with the control group. The Hannover-Brussels comparison data revealed that the S-N-B angle was significantly (p = .047) less in the Brussels cleft group. Conclusions The influence of surgical procedures in patients with UCLP might not be restricted to the maxilla but could influence mandibular spatial position to the cranial base. Because of these positional changes of the mandible, both cleft groups showed facial balance.

scholarly journals New Psychropotid species (Echinodermata Holothuroidea Elasipodida) of the Western Pacific with phylogenetic analyses

2021 ◽  
Author(s):  
Chuan Yu ◽  
Chunsheng Wang ◽  
Dongsheng Zhang ◽  
Ruiyan Zhang
Keyword(s):  
Phylogenetic Analysis ◽  
New Species ◽  
Deep Sea ◽  
Phylogenetic Analyses ◽  
The Other ◽  
Western Pacific ◽  
Morphological Examination ◽  
The Family ◽  
The Western Pacific ◽  
A New Species

Holothurians of the family Psychropotidae are widely distributed, but are the least studied deep-sea holothurians. On the expedition of the Western Pacific, four holothurians specimens of the family Psychropotidae were collected by the Jiaolong human operated vehicle (HOV). Through morphological examination, two of them were identified as a new species, Benthodytes jiaolongi sp. nov., which was characterized as having minute papillae, narrow brims, and terminal anus; the ossicles were either rods or absent. The remaining two specimens were identified as Psychropotes verrucicaudatus Xiao, Gong, Kou & Li, 2019, which was firstly recorded at Kyushu-Palau Ridge (KPR). The phylogenetic analysis confirmed the classification status of B. jiaolongi and P. verrucicaudatus, and indicated a paraphyletic relationship within the genus Benthodytes. The new species clustered with Benthodytes sanguinolenta and was separated from the clade of the other Benthodytes species. Furthermore, B. sanguinolenta and B. jiaolongi sp. nov. was found to be different from the other Benthodytes species based on their morphology. Therefore, a revision of the genus Benthodytes is needed to solve its phylogenetic relationship.

scholarly journals Masticatory musculature of the African mole-rats (Rodentia: Bathyergidae)

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e8847 ◽  
Author(s):  
Philip G. Cox ◽  
Chris G. Faulkes ◽  
Nigel C. Bennett
Keyword(s):  
Heterocephalus Glaber ◽  
Dominant Component ◽  
Mole Rat ◽  
Contrast Enhanced ◽  
The Family ◽  
Group Knowledge ◽  
Naked Mole Rat ◽  
Pterygoid Muscles ◽  
Functional Analyses ◽  
Muscles Of Mastication

The Bathyergidae, commonly known as blesmols or African mole-rats, is a family of rodents well-known for their subterranean lifestyle and tunnelling behaviour. Four of the five extant bathyergid genera (Cryptomys, Fukomys, Georychus and Heliophobius) are chisel-tooth diggers, that is they dig through soil with their enlarged incisors, whereas the remaining genus (Bathyergus) is a scratch-digger, only using its forelimbs for burrowing. Heterocephalus glaber, the naked mole-rat, is also a chisel-tooth digger and was until recently included within the Bathyergidae (as the most basally branching genus), but has now been placed by some researchers into its own family, the Heterocephalidae. Given the importance of the masticatory apparatus in habitat construction in this group, knowledge and understanding of the morphology and arrangement of the jaw-closing muscles in Bathyergidae is vital for future functional analyses. Here, we use diffusible iodine-based contrast-enhanced microCT to reveal and describe the muscles of mastication in representative specimens of each genus of bathyergid mole-rat and to compare them to the previously described musculature of the naked mole-rat. In all bathyergids, as in all rodents, the masseter muscle is the most dominant component of the masticatory musculature. However, the temporalis is also a relatively large muscle, a condition normally associated with sciuromorphous rodents. Unlike their hystricomorphous relatives, the bathyergids do not show an extension of the masseter through the infraorbital foramen on to the rostrum (other than a very slight protrusion in Cryptomys and Fukomys). Thus, morphologically, bathyergids are protrogomorphous, although this is thought to be secondarily derived rather than retained from ancestral rodents. Overall, the relative proportions of the jaw-closing muscles were found to be fairly consistent between genera except in Bathyergus, which was found to have an enlarged superficial masseter and relatively smaller pterygoid muscles. It is concluded that these differences may be a reflection of the behaviour of Bathyergus which, uniquely in the family, does not use its incisors for digging.

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