The First Jurassic turtle from India

A primitive cryptodiran turtle, Indochelys spatulata gen. et sp. nov., is described from the Early Jurassic Kota Formation, a member of the Upper Gondwana Group in the Pranhita-Godavari Valley, Deccan, India. The shell morphology of Indochelys differs substantially from that of the Triassic Proganochelys of Germany but is significantly similar to the oldest known Early Jurassic cryptodire, Kayentachelys , from the Kayenta Formation of Arizona. Indochelys also shares many shell characters with the Late Jurassic North American turtles, in particular Dinochelys . The new family Indochelyidae is proposed, which probably has the same phyletic status as that of Kayentachelyidae, with both evolving simultaneously in different regions.     

ON THE SYSTEMATIC POSITION OF PROSCIURUS LOHICULUS

The species Prosciurus lohiculus was erected by Matthew & Granger (1923), based on an upper jaw from Hsanda Gol Formation (Middle Oligocene), Mongolia. Later, Argyropulo (1939) described a lower jaw from the upper Oligocene of Kazakhstan, USSR, which was identified as Prosciurus sp. (lohiculus). Stehlin & Schaub (1951, p. 278) thought that the Kazakhstan lower jaw described by Argyropulo should belong to Plesispermophilus, leaving the holotype of P. lohiculus from Hsanda Gol Formation still in Prosciurus. Wood (1962, p. 236) transferred P. lohiculus into Plesispermophilus on the assumption that the Kazakhstan lower jaw belongs to the same form as the holotype from Hsanda Gol. Wood's opinion was followed by Mellett (1968, p. 6) and Shevyreva (1976, p. 22). Meanwhile, Kowalski (1974, p. 153) described several lower jaws, new material from the type locality, and believed they belongs to Prosciurus lohiculus and came to the conclusion that the Kazakhstan lower jaw was morphologically quite different from those he found in Tatal Gol, and hence could not belong to the species in question. Schmidt-Kittler and Vianey-Liaud (1979; p. 73) agreed with Kowalski and gave further evidence that the upper teeth of true Plesispermophilus was also different from those of P. lohiculus and that the lower jaw from Kazakhstan might well be of Plesispermophilus. Irrespective of these disagreements, all the authors consented to include P. lohiculus in Prosciurinae (Aplodontidae).     

A new tritylodontid from the Kayenta formation of Arizona

Kayentatherium wellesigen. sp. now is a new tritylodont (Thcrapsida: Synapsida) from the Kayenta Formation of Arizona, U.S.A. Only the skull and parts of the lower jaw are known. The first upper incisor is apparently absent, so the dentition consists of one upper incisor followed, after a diastema, by a row of postcanines, which are replaced posteriorly. The cusp formula of these upper postcanines is 2, 2 (+ a ) 2, a being a tiny mesial cusp. The mean breadth/length ratio of these teeth is 1.59. Kayentatherium is related to the Tritylodon Bienotherium lineage, but is considerably more advanced than the latter, which is of Upper Triassic Lower Jurassic age. This indicates that the Kayenta formation must be Lower or Middle Jurassic age, with agrees with the conclusions of Welles.     

Scampering,trotting, walking tridactyl bipedal dinosaurs in southern Africa: ichnological account of a Lower Jurassic palaeosurface (upper Elliot Formation,Roma Valley) in Lesotho

In Gondwana, Early Jurassic dinosaur track sites are especially concentrated in Lesotho. Despite intensive investigations during the third quarter of the twentieth century, a limited number of vertebrate track sites of this country have been studied with rigorous ichnological and sedimentological methodology. Here, we present a previously mentioned, but undescribed track site in the upper Elliot Formation (Hettangian?) of Lesotho, located near Roma (at Lephoto dam). Two tridactyl ichnite morphologies, made by bipedal vertebrate trackmakers are recognised. The first can be identified as Grallator-like, an ichnotaxon common in the Lower Jurassic of both Laurasia and Gondwana that can be attributed to small and medium-size theropod dinosaurs. In contrast, the second ichnite type is reminiscent of Trisauropodiscus, which is a rare ichnotaxon that resembles tracks of small birds and is known with certainty in Lesotho from only a few places. We suggest that at our upper Elliot Formation study site, Trisauropodiscus was potentially made by a heterodontosaurid ornithischian dinosaur. Our work provides further evidence that the ichnological record of the Stormberg Group of southern Africa is in a unique position to shed light not only on Early Jurassic biostratigraphy and palaeoenvironments but also on the biodiversity and palaeobiology of early dinosaurs.     

第四纪响蜥(Tinosaurus)化石的首次发现

在陕西洛南张坪洞穴的第四系中采得一些响蜥类(Tinosaurus)化石,有保存相当完好的上下齿骨和齿列,这是响蜥在第四纪的首次报道,使该属化石的地史分布从早第三纪延伸到第四纪。新材料下颌骨较粗壮,但个体很小,有齿间沟,同时兼具亚洲种及北美种的某些特征,因此建立一新种Tinosaurus luonanensis sp．nov．。     

Pterosaur remains from the Cretaceous of Morocco

New pterosaur remains consisting of jaw fragments of toothless taxa and isolated teeth are described from the red beds of the Kern Kern region of southern Morocco. The stratigraphic position of those red beds is discussed and it is concluded that they are in all likelihood early Cenomanian in age. At least four taxa of pterodactyloid pterosaurs are present. The toothless jaw fragments are referred to the families ?Pteranodontidae, ?Azhdarchidae and Tapejaridae. Four different morphotypes can be distinguished among the isolated teeth. They are tentatively referred to the Ornithocheiridae. This assemblage reveals a high diversity of pterosaurs in Africa during the early Upper Cretaceous. The possible occurrence of tapejarids and anhanguerids indicates relationships with the somewhat older pterosaur assemblage from the Santana Formation (Aptian/Albian) of Brazil. If confirmed, the presence of azhdarchids and pteranodontids in the early Cenomanian suggests an early differentiation of these essentially late Late Cretaceous groups of large pterosaurs.     

Age and wisdom teeth in Nigeria

An attempt has been made to estimate the eruption age of wisdom teeth in the North Nigerian population. The present study was carried out on 654 boys and 584 girls of age groups ranging from 11-23 years. From the data collected estimates have been provided for the eruption age of the third molar. In general, teeth of the lower jaw erupt before those of the upper jaw. The teeth on the left side erupt earlier than those on the right side. The wisdom teeth erupt little earlier amongst boys (18 years) as compared with girls (18.5 years). In general, the wisdom teeth erupt in Nigerians with some constancy between the age of 15 and 21. The wisdom teeth fail to erupt in 5% of the individuals.     

A NEW BASAL PTEROSAUR GENUS FROM THE UPPER TRIASSIC OF THE NORTHERN CALCAREOUS ALPS OF SWITZERLAND

Abstract:  A lower jaw with multicusped teeth and a number of unique characteristics was discovered in an extensive exposure of the Upper Triassic Kössen Formation in the Northern Calcareous Alps. The ramus of the jaw is high and dominated by a row of large, oval foramina that lies parallel to the tooth row. In addition, the anterior portion of the dentary exhibits a large number of nutritive foramina and small pits, which might indicate an association with a soft tissue structure and/or the presence of a keratinous cover of that area during life. All elements of the jaw are thin-walled and hollow, possibly pneumatic. Two teeth are preserved within the dentary. One is tricuspid and the other bears four cuSPS. The teeth are noticeably small in comparison with the overall size of the ramus, being only one-third of the height of the ramus. The teeth show a strong similarity to those of the well-known basal pterosaur genus Eudimorphodon , whose jaw morphology, however, clearly differs from the specimen described in this study. The dentition and the pneumatic bone structure make an assignment to the Pterosauria plausible. Based on the great number of distinct morphological characters the specimen is described as Caviramus schesaplanensis gen. et sp. nov.     

Fabrosauridae,the basal family of ornithischian dinosaurs (Reptilia: Ornithopoda)

In fabrosaurids the upper jaw is flat and the lower jaw is slender so the ’cheek’ teeth are marginal and not inset as is the case in all other ornithischian dinosaurs. The ’cheek’ teeth of fabrosaurids have anteroposteriorly expanded crowns but lack wear surfaces formed by tooth to tooth contact. Two genera are recognized from the Triassic-Jurassic boundary of Lesotho with good material previously referred toFabrosaurus as a new genus that represents the most conservative ornithopod described to date. The anatomy ofNanosaurus (Upper Jurassic, U.S.A.) andEchinodon (Jurassic-Cretaceous boundary, England) is redescribed; in both genera the tooth bearing bone of the lower jaw is deepened posteriorly and inEchinodon there is a true canine tooth in the upper jaw.     

印度Mahanadi盆地井下二叠纪下冈瓦纳岩层的微体植物化石组合

Mahanadi河盆地的冈瓦纳型诸盆地位于印度的近中心地区,呈北西—东南走向分布。Mahanadi主要盆地内的几个重要煤田为Korda煤田,Mand—Raigarh煤田和Ib河煤田。Korda煤田的冈瓦纳系沉积向南东向延伸,经Mand—Raigarh煤田延续至Ib河煤田。Korda和Ib河两个煤田储量巨大,且长期来有小构造活动;而Mand—Raigarh煤田至今很少受到重视,勘探开发晚得多。文中首次对Mand-Raigarh煤田5个钻孔样品作了孢粉研究,以初现面、相对丰度等为特征,划分出7个孢粉组合带,时代从二叠纪最早期(Talchir组)至二叠纪末期(Raniga由组)。填补了东西两个煤田之间的生物地层研究空白。7个孢粉组合带为：i)Parasaccites-Plicatipollenites assemblage zone(相当于Talchir组）,ii)Sulcatisporites-Brevitriletes assemblage zone(相当于下Barakar组）,iii)Sulcatisporites-Rhizomaspora assemblage zone(少量Densipollenites存在说明其相当于上Barakar组）,iv)Densipollenites-Striatopodocarpites assemblage zone(相当于Barren Measures组）,v)Striatopodocarpites-Densipollenites assemblage zone(相当于下Raniganj组）,vi)Striatopodocarpites-Densipollenites-Sulcatisporites assemblage zone(相当于上Raniganj组）vii)Sriatopodocarpites-Alisporites assemblage zone(相当于Raniganj最上部到Kamthi组最下部）,Raniganj组沉积中见到小的皱缩裂隙、植物垂直根和根的印痕,似代表古土壤。     

Dental homologies in lamniform sharks (Chondrichthyes: Elasmobranchii).

The dentitions of lamniform sharks are said to exhibit a unique heterodonty called the "lamnoid tooth pattern." The presence of an inflated hollow "dental bulla" on each jaw cartilage allows the recognition of homologous teeth across most modern macrophagous lamniforms based on topographic correspondence through the "similarity test." In most macrophagous lamniforms, three tooth rows are supported by the upper dental bulla: two rows of large anterior teeth followed by a row of small intermediate teeth. The lower tooth row occluding between the two rows of upper anterior teeth is the first lower anterior tooth row. Like the first and second lower anterior tooth rows, the third lower tooth row is supported by the dental bulla and may be called the first lower intermediate tooth row. The lower intermediate tooth row occludes between the first and second upper lateral tooth rows situated distal to the upper dental bulla, and the rest of the upper and lower tooth rows, all called lateral tooth rows, occlude alternately. Tooth symmetry cannot be used to identify their dental homology. The presence of dental bullae can be regarded as a synapomorphy of Lamniformes and this character is more definable than the "lamnoid tooth pattern." The formation of the tooth pattern appears to be related to the evolution of dental bullae. This study constitutes the first demonstration of supraspecific tooth-to-tooth dental homologies in nonmammalian vertebrates.     

Supernumerary deciduous incisors and the order of eruption of the incisor teeth in the albino ferret

A radiological study of the developing dentition of the domestic albino ferret has revealed the presence of four upper and three lower deciduous functionless incisor teeth in each half of the jaw. The presence of the additional upper incisor tooth can only be accounted for in two ways:
(1) It arose as the result of a gene mutation within the closed colony.
(2) It is indicative of the fact that at some early date in the evolution of the Carnivora, four deciduous incisors were functional in each half of the jaw.     

The pharyngeal jaw apparatus of labrid fishes: A functional morphological perspective

Among the acanthopterygian fishes, the Labridae possess the most highly integrated and specialized pharyngeal jaw apparatus. The integrated feature involves many osteological components and aspects of muscle form, architecture, composition, and function. The upper jaw articulates by means of a true diarthrosis with the pharyngeal process of the parasphenoid, whereas the lower jaw has established physical contact with the cleithrum. Complex muscle fusions have contributed significantly in the development of a double muscle sling operating the lower jaw. The original levator externus 4 fuses with the central head of the obliquus posterior, whereas the original levator posterior combines with the lateral head of the obliquus posterior as well as with the adductor branchialis 5. During the masticatory cycle, both upper and lower jaws undergo complex movement orbits resulting in shearing and crushing functions. Shearing occurs as the forward moving upper jaw collides with the dorsally held lower jaw. Crushing is effected by an extreme posterodorsal movement of the lower jaw against the retracted upper jaw, thereby establishing full occlusion of the teeth. The specialized morphological and functional design of the labrid pharyngeal jaw apparatus is similar to that found in cichlids. In sharp contrast to primitive acanthopterygian fishes, the Labridae and Cichlidae exhibit a spectacular morphological diversity that parallels their ecological diversification. Our combined functional and historical analysis has established a correlation between the complex integration of the pharyngeal jaw apparatus and morphological and ecological diversity in the Labridae and Cichlidae.     

A functional interpretation of the varanid dentition (Reptilia, Lacertilia, Varanidae)

A cinéradiographic analysis of the feeding movements in Varanus bengalensis produced the following results. The mouth is opened by raising the head (upper jaw) rather than by lowering the lower jaw. Starting from the resting position, the muzzle unit is elevated around 9 degrees relative to the rest of the skull during jaw opening; the quadrate swings anteriorly around 21 degrees. During jaw closure, the snout is depressed around 15 degrees relative to the rest of the skull, hence 6 degrees beyond the resting position. The quadrate swings backwards around 27 degrees. Amphikinesis is interpreted as allowing a stronger posterior recurvature of the maxillary teeth in Varanus. This increases the holding effect of the teeth without increasing their length, an adaptation of Varanus to capture relatively large prey. The formation of plicidentine (dentine infolding) in the teeth of Varanus increases the surface of attachment of the teeth on the supporting bone. Moreover, the dentine lamellae take up tensile and compressive stresses along their long axes upon axial or vertical loading of the teeth. The slope of pleurodonty is modelled so as to minimalize shear stress on the surface of ankylosis upon axial or vertical loading of the teeth.     

Biplanar X-ray motion analysis of the lower jaw movement during incisor interaction and mastication in the beaver (Castor fiber L. 1758)

The first biplanar X-ray motion analysis of mastication and food processing for Castor fiber is presented. While particles are chipped off interaction of incisors involves variable movements of the lower mandible and thus incisors. After jaw opening the tip of the lower incisors can reach different positions anteriorly of the upper incisors. Then the mandible moves upwards and backwards and brings the tips of the incisors into contact. The lower incisors slide along the wear facet of the upper to the ledge when the cheek teeth occlude. The glenoid fossa and lower jaw condyle are in close contact during incisor contact and no transverse movements are observed. Mastication involves interaction of the cheek teeth with no contact of the incisors. When the cheek teeth are in occlusal contact the mandible is moved forward and transverse, or mediolateral. In consecutive power strokes the jaw is moved alternately to the right and left side. When the jaw opens it is brought into a more central but not totally centred position. During mastication the condyles are positioned posteriorly to the glenoid allowing lateral movement of the mandible. The lateral movement is particularly noticeable in the anterior part of the mandible. With the lateral movements of the incisors one glenoid has to move posteriorly, the other anteriorly.     

Terrestrial feeding in the Mudskipper Periophthalmus (Pisces: Teleostei): A cineradiographic analysis

Mudskipping gobies (Periophthalminae) are among the most terrestrial of amphibious fishes. Specializations associated with terrestrial prey capture and deglutition have been studied in Periophthalmus koelreuteri by light and X-ray cinematography which permits direct visualization of pharyngeal jaw movement during deglutition. Anatomical specializations of the pharyngeal jaws are described and include depressible teeth, a large ventral process on ceratobranchial five, and muscular modifications.
Multiple terrestrial feedings occur by Periophthalmus without a return to the water, and cineradiography reveals that the buccal cavity is often filled with air during terrestrial excursions in contrast to some previous hypotheses. Transport of the prey into the oesophagus occurs primarily by anteroposterior movement of the upper pharyngeal jaw. The lower pharyngeal jaw plays a limited role in food transport and may serve primarily to hold and position prey. The bite between upper and lower pharyngeal jaws occurs between the anterior teeth, and both jaws are protracted together during raking of food into the oesophagus. Functional specializations correlated with terrestrial feeding include obligatory use of pharyngeal jaws for swallowing even small prey items and positioning of the prey in the pharynx by pharyngeal jaw and hyoid movements alone.
This analysis of terrestrial feeding allows hypotheses of design constraints imposed by the aquatic medium on fishes to be raised and tested.     

河南信阳平昌关盆地晚始新世哺乳动物化石

本文对河南省信阳平昌关盆地的哺乳动物化石进行了研究,并对含哺乳动物化石的层位李庄组的时代进行了讨论。认为李庄组可与內蒙伊尔丁曼纳组、豫西的卢氏组和核桃园组对比,比吴城盆地的三个岩组的时代要早,为晚始新世早期。