The First Tetrapod Finds from the Devonian (Upper Famennian) of Latvia

1994 ◽  
Vol 343 (1305) ◽  
pp. 303-328 ◽  
Author(s):  
Per Erik Ahlberg ◽  
Ervins Luksevics ◽  
Oleg Lebedev
Keyword(s):  
Upper Devonian ◽  
Marginal Tooth ◽  
Data Set ◽  
Limb Bone ◽  
Jaw Bones ◽  
Lower Jaw ◽  
Dorsal Process ◽  
Upper Jaw

Ventastega curonica, from the Upper Famennian Ketleri Formation, is the first tetrapod find from the Upper Devonian of Latvia, and only the fourth adequately represented Devonian tetrapod genus to be described. The taxon is represented by disarticulated cranial and postcranial elements from two localities, Ketleri on the Venta River and Pavari on the Ciecere River. A second tetrapod, represented by a single mandibular fragment, appears to be present at Ketleri. The lower jaw of Ventastega is strikingly primitive in retaining fangs on the coronoid series, but shares many characters with those of other known Devonian tetrapods. Some of these features are interpreted as basal tetrapod synapomorphies; they provide a new data set for the identification of isolated tetrapod jaw fragments, and confirm the (previously disputed) tetrapod status of Metaxygnathus. The upper jaw bones of Ventastega are broadly similar to those of Acanthostega, Ichthyostega and Tulerpeton, as is the narial region. The lateral rostral bone is either very small or absent. A preopercular bone is present in the cheek, and the lacrimal is excluded from the orbit. The palate is closed. Palatine and vomer bear fangs which are set in the marginal tooth row. An isolated iliac blade from Pavari, probably attributable to Ventastega, resembles that of Acanthostega but may not have carried a dorsal process. Two clavicles from Pavari and Ketleri which may also belong to Ventastega are of a typical early tetrapod pattern, similar to Greerpeton but with a broader ventral blade. Non-attributable or doubtfully attributable bones from Ketleri include a probable tetrapod postorbital and a possible limb bone. Ventastega appears to be a tetrapod of the same broad `grade' as Ichthyostega and Acanthostega, but is arguably more primitive than either.

scholarly journals Morphometric regularities of the depth indices of dental arches in the mesocrane skull type

2018 ◽  
Vol 9 (4) ◽  
pp. 28-32
Author(s):  
E. Y. Efmova
Keyword(s):  
Morphometric Parameters ◽  
Cutting Edge ◽  
Clinical Aspects ◽  
Dental Arch ◽  
Men And Women ◽  
Lower Jaw ◽  
Upper Jaw ◽  
Point Of Intersection

Objective: to reveal the morphometric regularities of the depth indices of the dental arches of the upper and lower jaws of the mesocrane skull type.Material and methods: the morphometric parameters of the depth of the dental arches of the upper and lower jaws were investigated. Te work was performed on 144 preparations of mesocrane skull type of people of both sexes of mature age with physiological occlusion of teeth. Te depth of the dental arch was measured from the point located at the center of the cutting edge of the medial incisor to the point of intersection with the line connecting the distal surfaces of the tooth crowns at the level of the canines, frst premolars, second premolars, frst molars, and second molars.Results: the range of confdence limits of the depth of the dental arches of the upper jaw in men at the level of canines and premolars surpassed those of women. Te range of confdence limits of the depth of the dental arches of the lower jaw in men and women at all levels of measurement was similar.Conclusions: the indices of the confdence limits of the depth of the vestibular and palatal dental arches of the upper and lower jaws are revealed. Te new data obtained as a result of the research, supplement and expand the information on the studied parameters, both in theoretical and clinical aspects.

scholarly journals Studi Karakteristik Morfometrik Ikan Julung-Julung (Hemiramphus Archipelagicus) Di Daerah Intertidal Teluk Ekas

2016 ◽  
Vol 16 (2) ◽  
Author(s):  
I Gde Suryawan, Mahrus Dan Karnan
Keyword(s):  
Intertidal Zone ◽  
Morphological Characteristic ◽  
Morphometric Characteristic ◽  
Young Fish ◽  
Beach Seine ◽  
Area Method ◽  
Total Length ◽  
Lower Jaw ◽  
Upper Jaw ◽  
Swept Area

ABSTRAKPenelitian ini bertujuan untuk mengetahui karakteristik morfometrik dan meristik ikan julung-julung di Teluk Ekas, Lombok Timur. Sampel penelitian berjumlah 165 ikan yang di tangkap pada daerah intertidal dengan metode swept area menggunakan pukat pantai (beach seine) di tiga stasiun. Karakteristik morfologi yang terlihat dengan jelas pada ikan julung-julung ini yaitu memiliki rahang bawah dengan warna merah pada ujungnya dan memiliki ukuran yang jauh lebih panjang jika dibandingkan dengan rahang atasnya. Hasil pengukuran karakteristik morfometrik menunjukkan bahwa ikan julung-julung yang terdapat pada daerah intertidal perairan Teluk Ekas merupakan ikan muda (juvenile) dengan frekuensi panjang total (PT) tertinggi terdapat pada ukuran 13,1-15 cm. Kesimpulan dari penelitian ini menunjukkan bahwa ikan julung-julung di daerah intertidal Teluk Ekas memiliki karakteristik morfometrik yang hampir sama dengan ikan julung-julung pada umumnya. Kata-kata kunci: Ikan Julung-Julung, Karakteristik, Meristik, Morfometrik   ABSTRACT This research intended to know the morphometric and meristic characteristic of jumping halfbeak at Ekas Bay, East Lombok. The sample of this research consisted of 165 fishes which caught at intertidal zone using swept area method with beach seine in three stations. The morphological characteristic which can be seen clearly on jumping halfbeak has lower jaw with red tip and longer than its upper jaw. The results of measurement of morphometric characteristic proved that jumping halfbeak at intertidal zone of Ekas Bay were young fish (juvenile) total length highest frequency on range of 13,1-15 cm. The conclusion of this research is jumping halfbeak at the intertidal zone of Ekas Bay has the similar characteristic morphometric to the general one. Keywords: Characteristic, Jumping halfbeak, Meristic, Morphometric

scholarly journals Combination of Digital and Conventional Workflows in the CAD/CAM-Fabrication of an Implant-Supported Overdenture

Materials ◽  
2020 ◽  
Vol 13 (17) ◽  
pp. 3688
Author(s):  
Michael Benno Schmidt ◽  
Angelika Rauch ◽  
Marcus Schwarzer ◽  
Bernd Lethaus ◽  
Sebastian Hahnel
Keyword(s):  
Case Report ◽  
Selective Laser Sintering ◽  
Digital Manufacturing ◽  
Manufacturing Processes ◽  
Dental Practice ◽  
Current Case ◽  
Future Developments ◽  
Lower Jaw ◽  
Cad Cam ◽  
Upper Jaw

Completely digital workflows for the fabrication of implant-supported removable restorations are not yet common in clinical dental practice. The aim of the current case report is to illustrate a reliable and comfortable workflow that reasonably merges conventional and digital workflows for the CAD/CAM‑fabrication of implant-supported overdentures. The 53-year old patient was supplied with a digitally processed complete denture in the upper jaw and, simultaneously, with an overdenture supported by four interforaminal implants in the lower jaw. The overdenture included a completely digitally processed and manufactured alloy framework that had been fabricated by selective laser sintering. The case report indicates that digital manufacturing processes for extensive and complex removable restorations are possible. However, as it is currently not yet possible to digitally obtain functional impressions, future developments and innovations might focus on that issue.

The relationships of Uronemus : A Carboniferous dipnoan with highly modified tooth plates

1987 ◽  
Vol 317 (1185) ◽  
pp. 299-327 ◽  
Keyword(s):  
Tissue Type ◽  
Close Relative ◽  
Marginal Tooth ◽  
Thin Sections ◽  
Scanning Electron Microscope Study ◽  
Air Breathing ◽  
Dental Tissues ◽  
Lower Jaw ◽  
Tooth Plate ◽  
Evolutionary Phase

Previous accounts of the dentition of the Carboniferous dipnoan Uronemus have stressed the significance of the scattered small denticles. These, together with the marginal teeth and ridges, have been interpreted as primitive characters of the dipnoan dentition shared with three other genera: the Devonian Uranolophus and Griphognathus and the Carboniferous to Permian Conchopoma . Genera with tooth plates have been considered to be a monophyletic group in which tooth plates are a derived character; Uronemus has been excluded from this group in all previous investigations dealing with the significance of the dentition for determining relationships among dipnoans. The macromorphology of the dentition of Uronemus has been re-examined and correlated with the histology of all the dental tissues. Optical study of thin sections and scanning electron microscope study of the adjacent cut surfaces has shown that the hard, wear-resistant dentine of the teeth and ridges is petrodentine. The arrangement, growth, wear and histology of the dental tissues have been compared with those of denticulated and tooth-plated genera. The arrangement of new teeth relative to the tooth ridge, the pattern of wear along the ridge, and the type of dentine and its growth indicate that the dentition of Uronemus is best interpreted as a tooth plate with one long lingual tooth ridge and reduced lateral tooth rows. Therefore the marginal tooth ridges are not considered to be homologous with those of denticulate dipnoans such as Uranolophus . The presence of petrodentine, a tissue type only found in forms with tooth plates, is consistent with the view that the dentition is derived by modification of a radiate tooth plate. The denticles covering restricted regions of the palate and lower jaw are considered to have been a secondary acquisition. The suggestion that Conchopoma is a close relative of Uronemus is not accepted, and possible new relationships have been proposed. New data on Scaumenacia and Phaneropleuron , two other genera previously compared with Uronemus , are presented. Rhinodipterus , a form with elongate lingual ridges, is also discussed. Phaneropleuron is shown to have radiate tooth plates and not a marginal row of conical teeth as previously described. It is proposed that the tooth plate of Uronemus is derived from a dipterid type of plate. A discussion of some of the other factors involved in determining the relationships of the genus is given. From an examination of the use of the tongue for respiration and feeding by the extant Lepidosiren paradoxa , it is concluded that many features of dipnoan evolution in the tooth-plated lineage result from the adoption of air breathing after an early evolutionary phase of gill respiration, and that Uronemus was adapted for air breathing. The ‘denticulated’ lineage, which included genera such as Uranolophus and Griphognathus , shows none of the skeletal features associated with the presence of a tongue, and presumably did not become air breathing.

An Anglo-Saxon Disc Brooch from Northamptonshire

1962 ◽  
Vol 42 (1) ◽  
pp. 53-56
Author(s):  
Vera I. Evison
Keyword(s):  
The Body ◽  
The Other ◽  
Anglo Saxon ◽  
Disc Diameter ◽  
Thin Disc ◽  
Lower Jaw ◽  
Upper Jaw

A small gilt-bronze disc brooch was found at Little Houghton, Northants., in 1957, a surface find on a Roman site, and was acquired by Northampton Museum (pl. xv b, fig. 1). It is a thin disc, diameter 2·5 cm., tapering at the border, with remains of pin holder and catch at the back and shallow pattern in relief on the front. The gilding has rubbed off the higher parts of the pattern, and has disappeared entirely in places where the brooch has been damaged and bent, possibly by fire. The ornament consists of two Style II animals, identical except for the shape of the jaw. They are S-shaped, turning round to bite their own backs; the body continues directly into the angle of a back leg which crosses the body and ends at the border in the rudiments of a foot; a front limb shoots forward to interlock with the hind curve of the other animal; the head is an eye framed by a right-angle; in one case the upper jaw passes below the body and the lower jaw is short and curves only slightly outwards; in the other the upper jaw again runs below the body, and the lower jaw swings round and seems to meet the upper jaw behind in a complete loop. There is damage at this point, however, and on analogous evidence it is quite likely that the lower jaw did not join the upper, but swept on independently.

Jaws and radula of the Carboniferous ammonoid Cravenoceras

1995 ◽  
Vol 69 (4) ◽  
pp. 703-707 ◽  
Author(s):  
Kazushige Tanabe ◽  
Royal H. Mapes
Keyword(s):  
The Body ◽  
Anterior Portion ◽  
Phylogenetic Affinity ◽  
Body Chamber ◽  
Lower Jaw ◽  
Upper Jaw ◽  
Marginal Plates ◽  
Buccal Space

A well-preserved mouth apparatus consisting of jaws and a radula was found in situ within the body chamber of the goniatite Cravenoceras fayettevillae Gordon, 1965 (Neoglyphiocerataceae: Cravenoceratidae), from the middle Chesterian (Upper Mississippian) of Arkansas. Both upper and lower jaws consist of a black material. The lower jaw is characterized by a widely opened larger outer lamella and a shorter inner lamella. The upper jaw is fragmental. The radula is preserved in the anterior portion of the buccal space and comprises a series of tooth elements. Each transverse tooth row consists of seven teeth (a rhachidian and pairs of two lateral and one marginal teeth), with a pair of marginal plates. This arrangement is typical of radulae of other ammonoids of Carboniferous to Cretaceous age, coleoids, and the orthoconic “nautiloid” Michelinoceras (Silurian, Michelinocerida), suggesting a phylogenetic affinity among them.

Orthopedic Protraction of the Upper Jaw in Cleft Lip and Palate Patients during the Deciduous and Mixed Dentition Periods in Comparison with Normal Growth and Development

1993 ◽  
Vol 30 (2) ◽  
pp. 182-194 ◽  
Author(s):  
Rolf S. Tindlund ◽  
Per Rygh ◽  
Olav E. Bøe
Keyword(s):  
Cleft Lip ◽  
Cleft Lip And Palate ◽  
Normal Growth ◽  
Mixed Dentition ◽  
Deciduous Dentition ◽  
Lower Jaw ◽  
Lateral Cephalograms ◽  
Anterior Position ◽  
Upper Jaw ◽  
Posterior Position

Cleft lip and palate (CLP) patients often develop maxillary retrusion after cleft repair. Since 1977, a group of 98 cases with negative overjet (anterior crossbite) during the period of deciduous dentition has been treated by the Bergen CLP team. The purpose of treatment has been to achieve favorable occlusion with positive overjet and overbite by means of anterior orthopedic traction (protraction). The average age at start of treatment was 6 years 11 months, and mean treatment duration was 13 months. The protraction force was 700 g. The serial lateral cephalograms of the treated CLP group were compared with those of a noncleft group with normal growth. Normalization of the sagittal maxillomandibular relationship (ANB angle) was achieved. Significant changes were a more anterior position of the upper jaw, and a more posterior position of the lower jaw, due to mandibular clockwise rotation. The variation was considerable. This paper reports the overall changes in the whole CLP group (ALL-C group).

Stolephorus babarani, a new species of anchovy (Teleostei: Clupeiformes: Engraulidae) from Panay Island, central Philippines

Zootaxa ◽  
2020 ◽  
Vol 4718 (4) ◽  
pp. 509-520 ◽  
Author(s):  
HARUTAKA HATA ◽  
SÉBASTIEN LAVOUÉ ◽  
HIROYUKI MOTOMURA
Keyword(s):  
New Species ◽  
Standard Length ◽  
Posterior Margin ◽  
Mitochondrial Coi ◽  
Dorsal Fin ◽  
Lower Jaw ◽  
Upper Jaw ◽  
Gill Raker ◽  
A New Species ◽  
Pelvic Fin

The new anchovy Stolephorus babarani n. sp. is described on the basis of 26 specimens collected from Panay Island, central Philippines. The new species closely resembles Stolephorus bataviensis Hardenberg 1933 and Stolephorus baweanensis Hardenberg 1933, all these species having a long upper jaw (posterior tip extending beyond posterior margin of preopercle), and numerous dusky spots on the suborbital area (in adults), snout and lower jaw tip. However, the new species differs from S. bataviensis by usually having the posterior tip of the depressed pelvic fin not reaching to vertical through the dorsal-fin origin (vs. extending beyond vertical through dorsal-fin origin), a shorter head (23.9–25.5% of standard length vs. 25.3–28.0%), and a greater distance between the dorsal-fin origin and pectoral-fin insertion (D–P1; 133.9–151.8% of head length vs. 109.9–136.3%). Stolephorus babarani is distinguished from S. baweanensis by having a shorter snout (3.6–3.9% of standard length vs. 3.8–4.6%). Moreover, the new species can be distinguished from S. bataviensis and S. baweanensis by higher gill raker counts on the first and second gill arches (16–18 + 21–23 and 10–13 + 18–21, respectively, vs. 14–17 + 19–22 and 9–12 + 17–20 in S. bataviensis and 14–17 + 19–22 and 9–12 + 17–21 in S. baweanensis). Stolephorus babarani is separated by 5.3% and 10.7% mean p-distances in the mitochondrial COI from S. baweanensis and S. bataviensis, respectively. 

Aspects of the Development of the Upper Jaw Bones in Teleosts

Copeia ◽  
1964 ◽  
Vol 1964 (2) ◽  
pp. 375 ◽  
Author(s):  
Frederick H. Berry
Keyword(s):  
Jaw Bones ◽  
Upper Jaw

scholarly journals Modeling Edar expression reveals the hidden dynamics of tool signaling center patterning

2018 ◽  
Author(s):  
Alexa Sadier ◽  
Monika Twarogowska ◽  
Klara Steklikova ◽  
Luke Hayden ◽  
Anne Lambert ◽  
...  
Keyword(s):  
Pattern Formation ◽  
Tooth Germ ◽  
Secondary Process ◽  
Direct Process ◽  
Dynamic Nature ◽  
Organ Cultures ◽  
Lower Jaw ◽  
Signaling Center ◽  
Upper Jaw ◽  
Activator Inhibitor

AbstractThe generation of patterns during development is generally viewed as a direct process. In the mouse jaw, however, the sequential patterning of molars initiates with abortive tooth signaling centers called MS and R2, thought to be vestiges of the lost rodent premolars. Moreover, the mature signaling center of the first molar (M1) is formed from the fusion of two signaling centers (R2 and early M1). Here, we report that Edar expression reveals the hidden dynamics of signalling centers patterning. First, Edar expression evidenced a hidden two-step patterning process that we modelled with a single activator-inhibitor pair: the epithelium is initially broadly activated, then activation becomes restricted in space to give rise to the signalling centers. Second, Edar expression unveils successive phases of pattern making and pattern erasing events, a phenomenon that we called a developmental palimpsest. MS is erased by a broad activation for the benefit of R2, which itself is erased before it recovers when the first molar signaling center forms. In the lower but not the upper jaw, the two neighboring signaling centers then fuse into a single elongated center. Our model recapitulated the erasure of the R2 signaling center by the wave of activation that precedes the formation of M1 signaling center, and predicted the surprising rescue of R2 in the context of an Edar mutant with reduced activation. It suggested that R2 was not intrinsically defective, but actively outcompeted by M1 formation. We confirmed this by cultivating R2 separately from the posterior tissue and showing it could then generate a tooth. Finally, by introducing chemotaxis as a secondary process of tooth germ maturation, we recapitulated the fusion of R2 and M1 in the lower jaw only, and the loss of fusion when Edar function is impaired in organ cultures. In conclusion, we have uncovered a highly indirect and dynamic nature of pattern formation in the molar field that could nevertheless be simulated with simple mathematical models. Our study argues for viewing embryonic patterns as dynamical objects rather than as fixed endpoints, where dynamics is essential to the outcome of the patterning process.

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