Single Row Of Teeth Research Articles

Composite Antler Combs from Olbia Pontica

In this paper, for the first time are presented the full selection of finds of antler composite combs with a single row of teeth from Olbia Pontica. All of them belong to the Cherniakhiv culture and are related to the time of the last settlement of the territory of the ancient city. From a typological point of view, all of them can be divided into two groups: combs with semicircular or trapezoidal handle and, slightly older than them, comb handles of a complex shape, which is based on a rectangle with a semicircular middle part.

Antler Comb Production in the Settlement at Suceagu-Rădaia (Cluj County). A Contribution to the Study of the Cultural Contacts at the Beginnings of the Migration Period

The authors are presenting the antler combs discovered as part of the rural settlement at Suceagu – Rădaia, Cluj County. From the very beginning of the archaeological research, the numerous fragments of processed antler pointed towards the presence of a workshop similar to those already known at Bârlad – “Valea Seacă” or from other contemporary settlements in the Central-Eastern European region. The typological classification of the combs discovered here illustrated the presence of three types of combs having a single row of teeth and semi-circular handle, as well as double-sided combs. Of great significance is the zoomorphic decoration present on one of the combs belonging to one of the combs having a single row of teeth and semi-circular handle. The association of combs with a single row of teeth with double-sided ones represents a chronological as well as a cultural “marker” for the Early Migration period, other known analogies pointing towards the area of the Late Roman Pannonian Limes. Double-sided combs are found in a small number in the Sântana de Mureș – Černjachov environment, the chronology of these types of combs, as well as of other small finds identified in the Suceagu – Rădaia settlement, accounting for the presence of antler comb workshops here, during the chronological stages D1-D2. The presence of a production centre for double-sided combs at Pericei, a site positioned beyond the north-western limes of the former province of Dacia Porolissensis, represents a milestone that marks a possible route for cultural influences reaching towards the settlement at Suceagu – Rădaia. To conclude, the present study illustrates the existence of a cultural mixture between the local Sântana de Mureș – Černjachov milieu with northern cultural influences coming from the environment of the Germanic federates in the area of the Pannonian limes. Such a complex phenomenon should have its beginnings around AD 400, at a time when the important cultural environments of the Sântana de Mureș – Černjachov and Przeworsk cultures are starting to fade out of their existence. Mediation between the areas of southern Poland and north-western Transylvania took place, as indicated by the spatial distribution of numerous metal or ceramic artefacts through settlements in eastern Slovakia and north-eastern Hungary, areas that acted as real bridgeheads over the Carpathian Basin.

The Vertebrate Tooth Row: Is It Initiated by a Single Organizing Tooth?

Teeth are one of the most fascinating innovations of vertebrates. Their diversity of shape, size, location, and number in vertebrates is astonishing. If the molecular mechanisms underlying the morphogenesis of individual teeth are now relatively well understood, thanks to the detailed experimental work that has been performed in model organisms (mainly mouse and zebrafish), the mechanisms that control the organization of the dentition are still a mystery. Mammals display simplified dentitions when compared to other vertebrates with only a single tooth row positioned in the anterior part of the mouth, whereas other vertebrates exhibit tooth rows in many locations. As proposed 60 years ago, tooth rows can be formed sequentially from an initiator tooth. Recent results in zebrafish have now largely confirmed this hypothesis. Here this observation is generalized upon and it is suggested that in most vertebrates tooth rows could form sequentially from a single initiator tooth.

A new onychodont (Osteichthyes; Sarcopterygii) from the Middle Devonian of Morocco and its bearing on early osteichthyan evolution

A new onychodont sarcopterygian is described from the Middle Devonian (Eifelian) of Morocco. Selenodus aquesbiae gen. et sp. nov. is characterized by a unique suite of traits among onychodonts such as a large maxilla with a rounded posterior expansion and a straight ventral margin, the presence of a single supraorbital, and a reduced opercular series. It also displays certain features commonly found in onychodontids and early sarcopterygians, like a lateral rostral contacting the orbit through a narrow posterodorsal projection, numerous sclerotic plates surrounding the orbit, the occurrence of an accessory row of small denticles labially lining the single row of teeth from the upper and lower jaws, a prearticular ornamented with small rounded tubercules, the postotic lateral line canal passing through the supratemporal, tabular and lateral extrascapular bones of the skull roof, and dermal bones and rounded scales ornamented by small dentine tubercules capped with enamel. All the fossil remains belong to a single individual representing a relatively large fish (around 1 m of estimated length based on the skull dimensions) for which the snout, cheek, and skull roof have been partially reconstructed. The well-preserved material comprises mainly the dermocranium but two branchial elements are known, adding to our knowledge of early osteichthyan endoskeleton. A phylogenetic analysis places Selenodus in an unresolved polytomy among onychodonts and coelacanths, enabling discussion of evolutionary scenarios and character combinations among early osteichthyans. The close relationship between onychodonts and actinistians is firmly established and suggests that all onychodont taxa are stem coelacanths. Selenodus represents the first occurrence of onychodonts from Africa and furnishes key information not only on onychodont morphology and interrelationships but also on their palaeobiogeographical distribution and Devonian faunal affinities between Euramerica and Gondwana.http://zoobank.org/urn:lsid:zoobank.org:pub:3FEB765B-E203-4015-BB48-20B108509F3B

Tooth development, histology, and enamel microstructure in Changchunsaurus parvus: Implications for dental evolution in ornithopod dinosaurs.

The great diversity of dinosaurian tooth shapes and sizes, and in particular, the amazing dental complexity in derived ornithischians has attracted a lot of attention. However, the evolution of dental batteries in hadrosaurids and ceratopsids is difficult to understand without a broader comparative framework. Here we describe tooth histology and development in the "middle" Cretaceous ornithischian dinosaur Changchunsaurus parvus, a small herbivore that has been characterized as an early ornithopod, or even as a more basal ornithischian. We use this taxon to show how a "typical" ornithischian dentition develops, copes with wear, and undergoes tooth replacement. Although in most respects the histological properties of their teeth are similar to those of other dinosaurs, we show that, as in other more derived ornithischians, in C. parvus the pulp chamber is not invaded fully by the newly developing replacement tooth until eruption is nearly complete. This allowed C. parvus to maintain an uninterrupted shearing surface along a single tooth row, while undergoing continuous tooth replacement. Our histological sections also show that the replacement foramina on the lingual surfaces of the jaws are likely the entry points for an externally placed dental lamina, a feature found in many other ornithischian dinosaurs. Surprisingly, our histological analysis also revealed the presence of wavy enamel, the phylogenetically earliest occurrence of this type of tissue. This contradicts previous interpretations that this peculiar type of enamel arose in association with more complex hadrosauroid dentitions. In view of its early appearance, we suggest that wavy enamel may have evolved in association with a shearing-type dentition in a roughly symmetrically-enameled crown, although its precise function still remains somewhat of a mystery.

Description of a new species and redescriptions of two rare species of Parapercis (Perciformes: Pinguipedidae) from the tropical Pacific Ocean.

Parapercis johnsoni sp. nov. is described based on 19 specimens from Marquesas Islands, French Polynesia. It differs from congeners in having a combination of the following characters: dorsal-fin rays V, 21; anal-fin rays I, 17; pectoral-fin rays modally 17; pored lateral-line scales modally 52 or 53; predorsal scales 7 or 8; transverse scale rows 3.5 or 4 + 14 or 15; total gill rakers on 1st gill arch 13-16; single row of teeth on vomer; 6 large canines at front of lower jaw; and a distinct coloration. Two rare species, P. flavescens Fourmanoir & Rivaton, 1979 and P. fuscolineata Fourmanoir, 1985, are redescribed based on the types and newly identified specimens. Comments on other species occurring in the area are provided.

European origin of placodont marine reptiles and the evolution of crushing dentition in Placodontia

Sauropterygia was the most successful marine reptile radiation in history, spanning almost the entire Mesozoic and exploiting a wide range of habitats and ecological niches. Here we report a new, exceptionally preserved skull of a juvenile stem placodont from the early Middle Triassic of the Netherlands, thus indicating a western Tethyan (European) origin for Placodontia, the most basal group of sauropterygians. A single row of teeth on an enlarged palatine supports this close relationship, although these are small and pointed instead of broad and flat, as is the case in placodonts, which demonstrate the strongest adaptation to a durophagous diet known in any reptile. Peg-like, slightly procumbent premaxillary teeth and an 'L-shaped' jugal also confirm a close relationship to basal placodonts. The new taxon provides insight into the evolution of placodont dentition, representing a transitional morphology between the plesiomorphic diapsid condition of palatal denticles and the specialized crushing teeth of placodonts.

Notes on the genus Harmonicon F.O.P.-Cambridge, 1896 (Araneae, Dipluridae) with description of a new species from French Guyana

Information on the genus Harmonicon F.O.P.-Cambridge, 1896, a key to the species and a new diagnosis differing from the one in Maréchal and Marty (1998) are provided. A new species is described: Harmonicon oiapoqueae differing from other species of the genus by the morphology of the posterior sternal sigilla, the more recurved, inverted U–shaped fovea, the amount and arrangement of maxillary cuspules, a single row of teeth on the claws of the palpal tarsus, longer and more slender legs III and IV in females, longer embolus, thinner bulb, and longer, more slender legs in males. The status of the putative junior synonyms of Harmonicon, Pseudohermachura Mello-Leitão, 1927 and Prosharmonicon Mello-Leitão, as well as the two species formerly assigned to Harmonicon, Harmonicon nigridorsi Mello-Leitão, 1924 and Harmonicon riveti Simon, 1903, is discussed.

On the function of the ultimate legs of <I>Cryptops</I> and <I>Theatops</I> (Chilopoda, Scolopendromorpha)

Statements in the literature suggest that the scolopendromorph centipedes Cryptops , Theatops and Plutonium use their ultimate legs to capture prey. It has been suggested that when the ultimate legs of Cryptops are exed the tibial and tarsal saw teeth are opposed, however, this is not so. There are relatively few observations of prey capture by Cryptops and none involve the ultimate legs. It is suggested that the ultimate legs are defensive; trapping some part of a potential predator and then being autotomised as the centipede makes good its escape. Although they may be involved in holding predators, this may not be the primary use of the saw teeth. In some New Zealand species the tibial saw teeth in males are arranged in several rows whereas in females there is a single row of teeth. The saw teeth may, therefore function in sexual recognition. Saw teeth may also function in species recognition before pairing takes place. That the ultimate legs of Theatops are involved in prey capture seems doubtful. Observations of the movements of the ultimate legs in living specimens and, particularly, on feeding are required.

Notes on the cranium of the paedomorphic Eurycea rathbuni (STEJNEGER, 1896) (Urodela: Plethodontidae) with special regard to the dentition

We illustrate the skull, the lower jaw, and especially the dentition of the highly specialized troglobitic salamander Eurycea rathbuni using cleared and stained specimens, scanning electron microscopy, and a few histological sections. Arrangement of the skeletal elements corresponds to earlier descriptions. Dentigerous bones are the fused premaxillae, the vomeres, the palatinal portions of the palatopterygoid in the upper jaw and palate, and the dentaries and coronoids in the lower jaw. Each bone bears a single row of teeth, which are especially numerous and small on the premaxillae and dentaries. Generally, teeth are monocuspid and most are recurved. The dividing zones are unrecognisable to slightly distinct, but do not reach the fully transformed state. Absence or only traces of pedicellation, monocuspidity and an enlarged base are typical for urodele teeth in a relative early stage of development.

Why we have a single row of teeth

Why we have a single row of teeth

The skull and the palaeoecological significance of Labidosaurus hamatus, a captorhinid reptile from the Lower Permian of Texas

The cranial skeleton of the large captorhinid reptile Labidosaurus hamatus, known only from the Lower Permian of Texas, is described on the basis of new, undescribed specimens. Labidosaurus is distinguished from other captorhinids by the more extreme sloping of the ventral (alveolar) margin of the premaxilla, a low dorsum sellae of the parabasisphenoid, a reduced prootic, a narrow stapes, and a relatively small foramen intermandibularis medius. Despite the presence of a single row of teeth in each jaw, the skull of Labidosaurus resembles most closely those of moradisaurines, the large multiple-tooth-rowed captorhinids of the latest Early and Middle Permian. A phylogenetic analysis confirms that the single-tooth-rowed L. hamatus is related most closely to moradisaurines within Captorhinidae, a relationship that supports the hypothesis of a diphyletic origin for multiple rows of marginal teeth in captorhinids (in the genus Captorhinus and in the clade Moradisaurinae). In view of the close relationship between L. hamatus and moradisaurines, which are regarded to have been herbivorous, L. hamatus is a critical taxon for studies of the evolution of herbivory in early tetrapods. L. hamatus shares several trademark features of herbivorous adaptation with moradisaurines, which suggest that this captorhinid species was omnivorous. As such, it represents a transitional taxon between faunivorous basal reptiles and the herbivorous moradisaurines. © 2007 The Linnean Society of London, Zoological Journal of the Linnean Society, 2007, 149, 237–262.

A NEW DERCETID FISH (NEOTELEOSTEI: AULOPIFORMES) FROM THE TURONIAN OF THE PELOTAS BASIN, SOUTHERN BRAZIL

Abstract: Dercetid fishes are common in Tethyan marine deposits of Europe, Asia and Africa. In this paper, we describe a South American dercetid fish, Brazilodercetis longirostris gen. et sp. nov., based on juvenile and adult specimens found in core samples at c. 4000 m sediment depth in the Atlântida Formation (Pelotas Basin, southern Brazil). Brazilodercetis longirostris is a slender, elongate fish recognized on the basis of the following features: prominent snout; contact between mesethmoid and frontals very anterior to the orbit; mesethmoid separating the premaxillae for half of their length; juvenile specimens bearing wedge‐like teeth on the anterior third of maxilla; long and shallow crest crossing epioccipital, parietal and posterior border of frontal; a pipe‐like preopercle; and reduced neural spine at the middle point of neural arch. Brazilodercetis shares a number of features with the other dercetids, including a pointed snout that is longer than the lower jaw (with Rhynchodercetis and Hastichthys), a medioparietal skull roof (with Cyranichthys and Benthesikyme), an unroofed posttemporal fossa (with Dercetoides, Rhynchodercetis and Pelargorhynchus), a flange on the anguloarticular (with Dercetoides, Hastichthys, Rhynchodercetis and Cyranichthys), untoothed premaxillae (with Hastichthys and probably Rhynchodercetis), and a single row of teeth on the maxillae (with Dercetis, Benthesikyme, Rhynchodercetis, Pelargorhynchus, Dercetoides and Hastichthys).

Unilateral antler combs from Romuliana

In the course of investigations at Romuliana nine antler three-partite combs with a single row of teeth were found in the Late Roman horizons dating from the late 4th - mid 5th century. They were found in Tower 19, in the Palace II sector and in the Thermae sector. The combs can be classified as two types: three-partite unilateral combs with semicircular handle (Petkovic comb type VII) and three-partite unilateral combs with triangular handle decorated with horse protomes (Petkovic comb type VI). Two groups of these finds were distinguished after more detailed analysis; the earlier one including specimens originating from the Chernyahov-S?ntana de Mure? culture and later one including specimens made under "barbarian"influence and produced in Romuliana. These finds confirm the continuity of settlement at Romuliana in the Late Roman period, from the final quarter of the 4th until the end of the 5th century and open up the question of the character of the settlement.

Myxiops aphos, new characid genus and species (Characiformes: Characidae) from the rio Lençóis, Bahia, Brazil

Myxiops aphos, new genus and species, is described from a river in the eastern portion of Bahia State, Brazil. Myxiops is distinguished from all other characid genera by the combination of the following features: infraorbitals fused in a unique fashion, resulting always in less than six autogenous bones; a single tooth row in the premaxilla; presence of somewhat pedunculate teeth, expanded and compressed distally, with cusps similar in shape and perfectly aligned along distal margin; ventral margin of toothed portion of maxillary curved towards ventral margin of premaxilla and maxillary teeth forming a continuous series with premaxillary teeth; margins of pre- and postzygapophyses with projections anteriorly and posteriorly directed; accumulation of epithelial cells forming globular structures distributed over head and scales; and base of anal fin without scales covering basal portion of unbranched and anterior branched rays. The presence of these features in other characids is discussed.

Evolutionary trend in feeding habits of Girella (Perciformes: Girellidae)

Although some Girella species are herbivorous, having basically tricuspid teeth, some are omnivorous. To determine the evolutionary trends in feeding habits of Girella, the phylogenetic relationships of several species of Girella were estimated by partially sequencing the mitochondrially encoded NADH dehydrogenase subunit 2 gene, and the dentition and adductor mandibulae complex of each species were examined. The cladogram determined from the mitochondrial DNA analysis indicated that multiple tooth-rows containing incisor-like teeth existed in adults of the ancestral species of Girella, species with a single tooth-row of tricuspid teeth in the adult stage having diverged subsequently on several occasions. The tendinous connections between each section of the adductor mandibulae complex are believed to have been simple in the ancestral species, more complicated connections also having diverged later on several occasions. Multiple tooth-rows containing incisor-like teeth and the simple adductor mandibulae complex are deduced as adaptations to herbivory; on the other hand, a single tooth-row of tricuspid teeth and the complicated adductor mandibulae complex are deduced as adaptations to omnivory. Therefore, the ancestral species of Girella is suggested as having been adapted to herbivory, with species adapted to omnivory having diverged on several subsequent occasions.

Chromidotilapia melaniae and C. nana, two new cichlid species (Perciformes, Cichlidae) from Gabon, Central Africa

Chromidotilapia melaniae and C. nana, two new cichlid species, are described from southern Gabon and the southern parts of the Ogooue-River system in Gabon. C. melaniae differs from congeners by a combination of coloration, morphometric and meristic characters. C. nana is the smallest known species of the genus and is distinguished from congeners in having a single row of teeth in both jaws of adults (versus multiple rows). Both new species are pair-bonding, biparental, oviphilic mouthbrooders. Intrageneric relationships of Chromidotilapia in Gabon are discussed.

Revision of the genus Girella (Girellidae) from East Asia

The taxonomy of three species ofGirella from East Asian waters,G. punctata Gray, 1835,G. leonina (Richardson, 1846) andG. mezina Jordan & Starks, 1907, is reviewed and intraspecific (individual and ontogenic) variations detailed.Girella mezina is characterized by a very wide mouth and thick upper lip, the soft-rayed portion of the anal fin high and round, dorsal profile of the head abruptly slanting in front of the eyes in adults, a transverse yellow band on the body in life, and 3–4 rows of teeth along the outer jaw margins, the central cusp of each tooth being wider than the lateral cusps in adults.Girella punctata is characterized by usually 2 rows of teeth along the outer jaw margins, usually 7 transverse series of scales between the lateral line and median spinous portion of the dorsal fin (TRac), and usually 52–55 pored lateral line scales (LLp). The species is variable in body and caudal fin shape, extent of squamation on the opercular region, and number and position of dark spots on the scales. It also exhibits ontogenetic variation in the number of tooth-rows.Girella leonina is characterized by a conspicuously black opercular flap, essentially a single row of teeth along the outer jaw margins, usually 10–11 TRac and usually 59–64 LLp. Intraspecific variations were evident in the mouth position, scale condition and body color after death, and in the number of pores of cephalic lateral line canals. The holotype ofG. punctata, previously known only from a figure, is described for the first time.Girella melanichthys is synonymized underG. punctata with a lectotype designated for the former.

Acanthodian fish remains from the Lower Devonian Cavan Bluff Limestone (Murrumbidgee Group), Taemas district, New South Wales

A well-preserved acanthodian fish fauna from the Lower Devonian (early Emsian) Cavan Bluff Limestone (Murrumbidgee Group), Taemas, Yass district, New South Wales, consists of dentigerous jawbones, fin spines and scales. Four taxa belonging to the Order Ischnacanthida are recognized including Taemasacanthus erroli Long, 1986 and newly described genera and species Cavanacanthus warrooensis gen. et sp. nov., Cambaracanthus goodhopensis gen. et sp. nov. and Taemasacanthus porca sp. nov. An amended diagnosis is provided for T. erroli. The jawbone of C. warrooensis gen. et sp. nov. is of moderate size and bears a single row of teeth with a circular parabasal section. The jawbone extends in an anterior direction beyond the foremost tooth. C. goodhopensis gen. et sp. nov. is a small to moderate sized jawbone bearing two teeth rows separated by a longitudinal ridge. The teeth of the mesial tooth row, the main tooth row, are circular in parabasal section. The lateral tooth row is weakly developed, bearing one or two incipient teeth. T. porca sp. nov. is represented by a small curved jawbone (mesially concave) bearing two teeth rows separated by a prominent longitudinal ridge. The teeth of both tooth rows have a circular parabasal section. The anterior extension of this ridge beyond the foremost tooth represents approximately one quarter the length of the jawbone. These fishes inhabited a Lower Devonian carbonate platform consisting of patch reefs built upon a muddy substrate on a low energy shallow marine shelf which was subjected to frequent storm surges.

Fluoride-induced developmental changes in enamel and dentine of European roe deer ( Capreolus capreolus L.) as a result of environmental pollution

Using macroscopic, microradiographic and scanning electron-microscopic methods, the effects of increased fluoride exposure on enamel and dentine formation were studied in fluorosed mandibular premolars and molars of roe deer from the heavily industrialized Ruhr area, Germany. Macroscopically, fluorosed teeth were characterized by opaque and stained enamel and in more severe cases also by enamel surface lesions, reduction or loss of enamel ridges on their occlusal surfaces and increased wear. Microradiographically, fluorosed enamel exhibited different degrees of subsurface hypomineralization, in part apparently indicating a fluoride effect during enamel maturation. In some specimens, a pronounced but varying enhancement of the pattern of Retzius lines was observed throughout the enamel, denoting strongly intermittent fluoride exposure during enamel matrix secretion. This variation in exposure was also reflected histologically in dentine, by bands of interglobular dentine and marked accentuation of incremental lines. Microradiography of sections through enamel surface hypoplastic lesions showed the enamel forming the bottom and partly also the walls of the lesions to be highly mineralized. Scanning electron microscopy showed that the outer enamel along the more pronounced hypoplastic lesions consisted of stacked, thin layers of ‘aprismatic’ enamel, indicating that the ameloblasts in these areas had lost the distal (rod-forming) regions of their Tomes' processes. These observations demonstrate that the origin of enamel hypoplasias in deer clearly differs from that in rodents, where fluoride induces the formation of subameloblastic cysts. The differences in the degree of fluorotic alteration between the teeth of a single tooth row could be related to the developmental sequence of the dentition in roe deer. The roe deer is thus considered to be a very sensitive and useful bioindicator of environmental pollution by fluorides.