Neue Multituberculaten-Zähne aus dem Barremium (Unter-Kreide) von Galve (Spanien)

Two new isolated upper anterior premolars (p^1–3) of multituberculates are described from the Barremian of Galve in Spain. One specimen is tricuspid and belongs toEobaatar hispanicus Hahn &Hahn, 1992. The other is the first tetracuspid p^1–3 known from Galve. It is very similar to respective teeth of the Paulchoffatiidae G.Hahn, 1969 from the Upper Jurassic of Portugal. Therefore, this very small tooth belongs very probably to the paulchoffatiid taxonGalveodon nannothus Hahn &Hahn, 1992 which is also characterized by tiny dimensions     

The relation of canine size to pattern and extent of attrition in baboons

For most genera of animals the association between dental morphology and diet is such that inferences concerning the diet can be made on the basis of the dentition alone. The canine is the one tooth that appears exempt from such generalisation and exhibits a wide range of variability of size and shape in all groups. In order to determine the effect of dimorphism of the canine on the dental apparatus, male and female specimens of Theropithecus and Papio baboons were examined. Occlusal relationships and dental pathology for 21 Theropithecus and 40 Papio skulls were recorded, and crown height measurements obtained for maxillary incisors, buccal and lingual molar cusps. Attrition was the most common and severe cause of abscess formation in older animals: the pattern of attrition differed in adult males and females, the latter showing more wear of the incisor and lingual molar cusps. Partial correlations for incisor, buccal and lingual molar cuspal crown height show a significant correlation between incisor and lingual cusp attrition in juveniles of both sexes and adult females (p < 0.01). Adult males show no correlation of attrition. It is proposed that the correlation of incisor and lingual molar cusp attrition is associated with anterior-posterior grinding movements, such as take place during incision, that the large canine present in the male limits such movements, the sharp blade-like canine being employed as a cutting tool. This use of the canine by reducing functional demands on other teeth, prolongs the utility of the dental apparatus, and hence the lifespan of its possessor.     

Multituberculaten-Zähne aus der Unter-Kreide (Barremium) von Pié Pajarón (Prov. Cuenca, Spanien)

Two isolated p1-3 from the Early Cretaceous (Barremian) of Pié Pajarón, region of Una, Spain, are described asEobaatar? pajaronensis n. sp. Both teeth are tricuspid. Their crown is lengthened posteriorly, and the posterior lingual cusp is surrounded by a broad convexely bent shelf. Such a morphology is unknown in other p^1-3 among the Plagiaulacida (Ameghino 1889)G. Hahn 1969. Therefore, the new species can be grouped only tentatively withEobaatar. Its stratigraphical age is secured by records of amphibians and reptiles.     

中国近代人群上颌前臼齿釉质-齿质连接面形状的三维几何形态测量

牙齿的釉质-齿质连接面(EDJ或Enamel-dentine junction)是釉质表面(OES或Outer enamel surface)形态的发生基础,其形态特征在牙齿发育早期形成,与遗传因素密切相关。为探讨EDJ形状在近代人群中的变异特点,本文使用显微断层扫描技术(micro-CT或micro-computed tomography)扫描了100例采自华中地区近代农业人群的上颌前臼齿(P~3和P~4各50例),并复原了EDJ表面三维结构。采用基于30个标志点(landmark)和半标志点(semi-landmark)的三维几何形态测量量化了上颌前臼齿EDJ表面形状。结果显示,牙齿内部舌侧尖区域变异程度较颊侧尖大。在人群内部,上颌前臼齿的变异方式主要表现在1)颊舌尖相互靠近或远离造成的咬合面深浅的差别;2)颊舌尖齿质最高点(dentine horn)相对高度的差异;3)舌侧尖近远中方向尺寸的变化;4)P~3颊侧尖近中脊的内收与外扩造成的整个轮廓形状的对称性变化;5)P~4整个咬合面轮廓MD/BL比值的大小差别。基于以上发现,本文进一步探讨了上颌前臼齿EDJ形状在两性或不同时代标本之间是否存在差异。平均形状的比较发现男性上颌前臼齿的舌尖相对较宽,颊侧尖近中脊相对较低。但主成分分析(Principal component analysis)和置换检验(Permutation test)显示两性差异未达到显著水平。同样,从新石器时代以来的各样本组之间在EDJ形状上的差别也没有达到统计上的显著水平。这一结果提示中国近代人群上颌前臼齿EDJ表面形状的变异特点至少可以追溯到全新世早期(本文使用标本最早来自距今6000-7000年前的新石器时代阶段)。未来EDJ的三维几何形态测量可通过扩大标本数量进一步探讨不同性别、不同地区人群、不同演化阶段之间的差异。     

A new assemblage of freshwater sharks (Chondrichthyes: Elasmobranchii) from the Upper Triassic of India

This study reports the first occurrence of a varied xenacanth assemblage from the Upper Triassic Tiki Formation of India, based on multiple well-preserved isolated teeth. Based on distinct tooth morphology, two species of the genus Mooreodontus are described: M. indicus and a new species, M. jaini. The new species is diagnosed based on a tricuspid crown containing two stout, slightly diverging lateral cusps pointing in the same direction, a high median cusp, crown-base angle almost at 90°, large, rounded, apical button with several foramina and multiple, 8–9 coarse vertical cristae on all the cusps. Dental anomaly in the form of a partial quadri-cuspidate xenacanthid tooth is present in the collection. Another group of xenacanthid teeth have bicuspid crowns with two upright, asymmetric cusps, where the mesial cusp is thicker than the distal one, and consistently lack a median cusp. Such distinct bicuspid tooth morphology is usually present in Palaeozoic forms and is reported for the first time from the Late Triassic. It is considered to belong to a new taxon, Tikiodontus asymmetricus nov. gen., nov. sp., of indeterminate family. Distinctive tooth histology also differentiates the two Indian genera Mooreodontus and Tikiodontus nov. gen. from other xenacanthid taxa. In addition, the Tiki assemblage has yielded multiple chondrichthyan dermal denticles, which may be subdivided into two morphotypes based on their robustness and presence/absence of linear ridges on the fused cusps. India holds a unique position in terms of its Late Triassic freshwater shark fauna, as it exhibits distinct Laurasian affinities. These freshwater sharks had restricted occurrences in other parts of the Gondwanan landmass.     

贵州盘县大洞更新世灵长类化石

本文记述贵州盘县大洞中－晚更新世洞穴堆积中的猴类化石,数量不多,被归入短尾猴（Ｍａｃａｃａａｒｃｔｏｉｄｅｓ）,熊猴（Ｍ．ｃｆ．ａｓｓａｍｅｎｓｉｓ）和疣猴亚科（Ｃｏｌｏｂｉｎａｅ）本研究为南方洞穴堆积单个灵长类牙齿的鉴定积累一些资料,同时也扩大了贵州省猴类化石的分布。     

Symmetry of non-carious cervical lesions in canines and premolars

Objectives: Clinically non‐carious cervical lesions (NCCLs) are frequently seen. The aim of this study was to investigate the relationship between the shape and symmetry of NCCLs, wear of cuSPS and triangular ridge, and the curvature of the tooth root. Methods: One hundred and twenty‐nine extracted human upper canine teeth and 274 extracted human upper premolar teeth with NCCLs were used in this study. The specimens were studied using photographs and three‐dimensional scanning. Results: Asymmetric NCCL was observed in 69.0% of the canines and 44.5% of the premolars. Wear of cusp and lingual ridges was observed in 82.9% and 93.0% of the canines, respectively. Wear of the buccal cusp and buccal triangular ridge was observed in 85.4% and 89.8% of the premolars, respectively. On the other hand, the wear of lingual cusp and lingual triangular ridge was observed in 89.1% and 93.8% of the premolars, respectively. The curvature of the root was observed in 48.1% of the canines and 43.4% of the premolars. Conclusions: There was no relationship between the symmetry of NCCLs, and the wear of cuSPS and triangular ridges for either canines or premolars. Although there was a relationship (p < 0.05) between the symmetry of NCCL and the curvature of the root in the canines, no relationship was observed between the symmetry of NCCL and the curvature of the root in the premolars.     

Occlusal Pattern in Paulchoffatiid Multituberculates and the Evolution of Cusp Morphology in Mammaliamorphs with Rodent-like Dentitions

Multituberculates developed a very complex masticatory apparatus during their long evolutionary history from the Jurassic to the Paleogene. Besides their rodent-like elongated incisors and diastemata, Cenozoic cimolodont Multituberculata display masticatory movements involving two distinct cycles in the mastication. An orthal slicing-crushing cycle associated with an enlarged lower fourth premolar precedes a palinal grinding cycle linked to upper molars with three longitudinal rows of cusps. With their plesiomorphic lower premolars and upper molars, the Late Jurassic/Early Cretaceous multituberculate family Paulchoffatiidae can provide the key for the understanding of the origin of the complex mastication of the Cimolodonta. Using for the first time propagation phase contrast Synchrotron X-Ray microtomography to perform both microwear and topographic analyses in order to characterize the mastication of Paulchoffatiidae, we digitized dental material from the Late Jurassic of the Guimarota Coal Mine (Leiria, Portugal) at the European Synchrotron Facility (Grenoble, France). Mastication in Paulchoffatiidae is characterized by a palinal grinding cycle. In contrast to Cimolodonta, no evidence of an orthal slicing-crushing cycle has been observed: the lower premolars mainly have a grinding function like the molars as they do exhibit buccal attrition facets bearing longitudinal striations. Nevertheless, the slightly oblique striations observed on the mesial part of the paulchoffatiid lower premolars possibly presage the orthal phase of the Cimolodonta. Our topographic analysis indicates that a strong relationship between individual cusp shape and direction of chewing is emphasized in rodents and rodent-like Mammaliamorpha such as Cimolodonta and Tritylodonta. Surprisingly, this relationship is not evident in Paulchoffatiidae. This unexpected result can be explained by the non-involvement in the attrition of many premolar cusps in Paulchoffatiidae, as indicated by our microwear analysis. The stronger the attrition, the more the direction of the masticatory movements influences the cusp morphology in Mammaliamorpha.     

记江苏泗洪首次发现森林古猿类化石

本文记述了在江苏泗洪松林庄发现的一种古猿类化石,它以个体小、颊齿宽、有发达的齿带等特征有别于我国云南的腊玛古猿、西瓦古猿;它也有别于在同一地点、同一层位发现的双沟醉猿。其形态与非洲的Proconsul属接近,根据这些形态特点和它的地史分布,我们订立了一新属一新种:Platodontopithecus jianghuaiensis,地质时代为中新世。     

Variations in atrioventricular valve innervation in four species of mammals

In this series of studies, the innervation patterns of whole-mount preparations of bicuspid and tricuspid valves were studied by light microscopy in the mouse, rat, guinea pig, and opossum. The acetylcholinesterase-positive networks of nerve fibers showed many similarities in the basic patterns of valve innervation in all of the species studied, but several interspecies variations were observed. The basal zone of the valve adjacent to the fibromuscular atrioventricular ring displayed the most dense plexus of nerves, with acetylcholinesterase-positive fibers being seen across the width of the valve. In the intermediate zone of the valve, less dense plexuses of nerve fibers were found; and these were more numerous in the cuspal areas and less numerous in the intervening commissural areas. In the distal portions of the valve, nerve networks arborized extensively, with some of their nerve fibers extending toward the chordae tendineae and the free edges of the valve cusps. Only in the guinea pig and opossum did these fibers reach the free margin of the valve cusp, where they either ended directly as free nerve endings or lay parallel to the free edge of the cusp, often running between adjacent chordae tendineae. Although the patterns of innervation were similar in both bicuspid and tricuspid valves, the innervation density of the bicuspid valve was greater than that of the tricuspid valve for each species examined. A distinguishing feature of guinea pig and opossum tricuspid valves was that their chordae tendineae were relatively more prominent and more densely innervated than the bicuspid chordae tendineae. Free nerve endings with no light microscopic evidence of specialization were present throughout the bicuspid and tricuspid valves of all species studied. Some nerve endings in the opossum showed evidence of specialization, with brush-like arborizations leading to presumed free terminals seen chiefly in the distal zone of the valve cusps. Although some general tendencies were apparent, we have demonstrated that interspecies heterogeneity exists in the terminal networks of the atrioventricular valves of mouse, rat, guinea pig, and opossum.     

Multituberculaten-Zähne aus dem Ober-Jura von Porto das Barcas (Portugal)

An isolated m₁ from the Upper Jurassic of Porto das Barcas, Portugal, is described asKuehneodon barcasensis n. sp. It is similar toK. uniradiculatus G. Hahn 1978 from the Guimarota Coal Pit, Portugal, especially in subdivision of the first and third buccal cusps into two cuspules. But it differs fromK. uniradiculatus in the breadth of the cusp-rows: The buccal row is nearly twice as broad as the lingual cusps row, whereas inK. uniradiculatus both rows are nearly of the same breadth. Moreover, the m₁ ofK. barcasensis is only 1 mm long, whereas the m₁ ofK. uniradiculatus are 1.6-1.9 mm in length. A second tooth, a p₃, is tentatively grouped withK. barcasensis. It is of the same small dimensions as the m₁ (1 mm long). It bears four serrations, and two basal cuspules. The exact stratigraphical age of these teeth is unknown, but their close affinities to the taxa of the Guimarota Coal Pit make an Oxfordian to Kimmeridgian age probable.     

Estimating canine tooth crown height in early Australopithecus

Canine tooth size reduction and the associated reduction in canine dimorphism is a basal hominin character that also provides important evidence for models of behavioral evolution. Two specimens of Australopithecus anamensis (KNM-KP 29287 and KNM-KP 29283) that do not preserve the canine crown, but do preserve the root or alveolus, appear to suggest that canine size variation and canine dimorphism in this species may have been greater than in other hominins. We evaluate canine root and crown dimensions in a series of extant hominoids, and estimate canine crown height in Australopithecus afarensis and A. anamensis. Our results demonstrate that it is possible to generate estimates of canine crown height from basal canine crown and root dimensions with a moderate degree of accuracy. Estimates of maxillary canine crown size for A. anamensis are slightly larger than those of A. afarensis, and are approximately the same size as canines of modern female chimpanzees. Estimated mandibular canine crown height is very similar in the two species. Variation within the A. anamensis sample of estimated canine crown heights is similar to that of modern humans, suggesting a low degree of sexual dimorphism. Inclusion of estimates for KNM-KP 29287 and KNM-KP 29283 does not substantially increase either the estimate of overall canine size or variation for A. anamensis.     

Characteristics of dentition in gekkonid lizards of the genus <Emphasis Type="Italic">Teratoscincus</Emphasis> and other Gekkota (Sauria,Reptilia)

The dentition and tooth crown microstructure of gekkonids and eublepharids are examined. Scanning electron microscopy shows that the lingual surface of teeth in these lizards has one, two, or, occasionally, several cusps separated by grooves. The teeth of geckoes usually have two (lingual and labial) cusps in the apical region. With respect to the number of teeth, the majority of Gekkota fall into two groups. The first includes a few species with many teeth (50 or more) in the dentary and maxilla, the eublepharids Goniurosaurus and Aeluroscalabotes, and the gekkonid Cyrtopodion louisiadensis. The second group, comprising most of the species, is subdivided into two subgroups, species with 20–30 or 30–40 teeth in jaw bones. Teratoscincus belongs to the first subgroup of the second group.     

Functional implications of enamel thickness in the lower molars of red colobus (Procolobus badius) and Japanese macaque (Macaca fuscata)

The purpose of this study is to determine whether teeth are likely to retain their functional efficiency throughout an individual's life time. This was done by comparing the enamel volume, the cross-sectional enamel area and the pattern of enamel distribution on unworn M(2)s of folivorous (Procolobus badius: red colobus; n=8) and frugivorous (Macaca fuscata: Japanese macaque; n=6) cercopithecids. The enamel volume of M. fuscata is significantly greater than that of P. badius. As the lower molars of colobines become worn, the dentine is exposed on the buccal cusps and narrow enamel rims are formed around the dentine exposures. The buccal enamel rims are especially well-developed and sharp, a pattern that has probably been selected for as being advantageous for shredding fibrous plant materials. The results of this study demonstrate that the enamel on the lingual side of the protoconid, where dentine exposure occurs first, is much thinner in P. badius than it is in M. fuscata. In addition, the dentine is exposed and thin enamel rims are formed faster in P. badius than in M. fuscata. Also, P. badius has significantly thinner and more uniform enamel distribution on the buccal wall of the crown and a higher protoconid. The buccal flare is well-developed in M. fuscata, but poorly developed in P. badius. It is tentatively suggested that the undeveloped flare and thinner enamel of P. badius combine to enable this species to maintain narrow rims, even after dental attrition, while the high cusps may be an adaptation for providing narrow enamel rims throughout life.     

Sexual dimorphism in a Lower Miocene moronid?

A series of questionable elements in certain specimens ofMorone cf.aequalis (Koken 1891) from Lower Miocene deposits near the village of Berkersheim, N of Frankfurt a. M. (Hessen, Germany) is described, which has not been known from any other percoid before. These elements are fully ossified and cover the cheek and the preopercular region. Even within well-preserved material, they are only present in some specimens. Therefore, they may be specialized structures that are indicative for sexual dimorphism. Nevertheless, they clearly differ from all other respective structures that have been described from teleosts: Multicellular epidermal horny tubercles (“breeding tubercles”) mainly consist of keratine and not of calciumphosphate. By contrast, contact organs consist of bone and are located mainly at the surface of the fin rays and scales, respectively. At present, “breeding tubercles” are the favorite interpretation and the original substance may have been replaced via post-mortem phosphatization.     

A nonadaptive dental trait

Compared to other anthropoid females, female cercopithecoids possess hypertrophied honing premolars (P₃) yet lack hypertrophied maxillary canines. In addition, female cercopithecoid maxillary canines are often tip-blunted, the crown rarely extends down to the entire shearing surface on the buccal face of P₃, and honing wear is usually confined to a small fraction of its hypertrophied buccal surface. The likely reason why the female P₃ has an unusually long buccal face is that genes involved in the expression of this morphology are also in males, for which the hypertrophied condition is adaptive—it serves as the honing surface for their hypertrophied canines. The data suggest that the hypertrophied P₃ of females is the correlated and nonadaptive response of an homologous characteristic. The possibility that this occurs in other female anthropoids and in other parts of the C/P complex is discussed, as well as the relevance of this phenomenon for understanding human canine evolution and identifying other traits which may also be examples of correlated response.     

POSTCANINE ROOT SYSTEM IN TRITYLODONTS

<正> Inspired by Dr. Tom Rich's letter inquiring the structure of the roots of tritylodont cheekteeth, we initiated this study. At first, only several isolated teeth were exposed. Later on, jaws and partial skull carrying the dentition have been included.The generic identification of the materials is based mainly on the morphology of the upper postcanine crowns. Among the four genera dealt with in this work, Yunnanodon is unique in having a cusp formula of 2-3-2:2 buccal, 3 median and 2 lingual cusps. From the smaller and a little medially situated posterior cusp of the lingual row, Lufengia could be separated from the other two genera.Bienotheroides is supposed to be distinguished by a cusp formula of 2-2-2, as those in the later tritylodonts: Stereognathus, Bocatherium, etc. However, in fact, this cusp pattern exists only in the type species, B. wanhsienensis. Another species, B. zigongensis from a lower horizon, namely, Lower Shaximiao Formation of Sichuan and Wucaiwan Formation of Xinjiang, possesses a cusp formula of 2-3-3, much similar to that of Bienotherium. Consequently, the localities and horizons are taken as a measure of discriminating those specimens with similar crown pattern, especially the lower postcanine teeth.     

New dental remains of Anoiapithecus and the first appearance datum of hominoids in the Iberian Peninsula

New dental remains of the fossil great ape Anoiapithecus brevirostris are described from the Middle Miocene local stratigraphic series of Abocador de Can Mata (ACM) in els Hostalets de Pierola (Vallès-Penedès Basin, NE Iberian Peninsula). These specimens correspond to maxillary fragments with upper teeth from two female individuals from two different localities: left P³–M¹ (IPS41712) from ACM/C3-Aj (type locality; 11.9 Ma [millions of years ago]); and right M¹–M² and left P⁴–M² (IPS35027) from ACM/C1-E* (12.3–12.2 Ma). Relative enamel thickness is also computed in the latter individual and re-evaluated in other Middle Miocene hominoids from ACM, in order to better assess their taxonomic affinities. With regard to maxillary sinus development, occlusal morphology, molar proportions and enamel thickness, the new specimens show greater resemblances with the (male) holotype specimen of A. brevirostris. They differ from Pierolapithecus catalaunicus in displaying less inflated crests, a more lingually-located hypocone, and relatively lower-crowned molars; from Dryopithecus fontani, in the relatively thicker enamel and lower-crowned molars; from Hispanopithecus spp., in the more inflated crown bases, less peripheral cusps and more restricted maxillary sinus; and from Hispanopithecus laietanus also in the thicker crests, more restricted occlusal foveae, and relatively lower-crowned molars. The new specimens of A. brevirostris show some slight differences compared with the holotype of this species: smaller size (presumably due to sexual size dimorphism), and less distally-tapering M² occlusal contour (which is highly variable in both extant and extinct hominoids). The reported remains provide valuable new evidence on dental intraspecific variation and sexual dimorphism in Anoiapithecus. From a taxonomic viewpoint, they support the distinction of this taxon from both Dryopithecus and Pierolapithecus. From a chronostratigraphic perspective, IPS35027 from ACM/C1-E* enlarges the known temporal distribution of Anoiapithecus, further representing the oldest record (first appearance datum) of hominoids in the Iberian Peninsula.