Isolated Dinosaur teeth have been discovered in the Upper Triassic locality of Habay-la-Vieille, in southern Belgium. Ornithischia are represented by three dental morphotypes; two of them closely resemble isolated teeth from the Middle or Upper Jurassic of Portugal and England. The presence of sauropods in the Upper Triassic of Europe is confirmed. Sauropods already had a wide geographical distribution during the Latest Triassic, as fossils have been discovered in South Africa, Thailand and western Europe. At Habay-la-Vieille, sauropods and prosauropods co-existed at the end of the Triassic. Two dental morphotypes may tentatively be referred to as theropod dinosaurs. The study of isolated teeth indicates that dinosaurs were already well diversified in the Latest Triassic of western Europe.
Des dents isolées de dinosaures ont été découvertes dans les Trias supérieur d’Habay-la-Vieille, en Lorraine belge. Les Ornithischia sont représentés par trois morphotypes, dont deux semblent très proches de dents isolées découvertes dans le Jurassique moyen à supérieur du Portugal et d’Angleterre. La présence de sauropodes dans le Trias supérieur d’Europe est confirmée. Les sauropodes occupaient déjà une aire de répartition géographique étendue au cours du Trias terminal, puisque des ossements ont été découverts en Afrique du Sud, en Thaïlande et en Europe occidentale. Des sauropodes et des prosauropodes ont coexisté à Habay-la-Vieille à la fin du Trias. Deux morphotypes dentaires peuvent prudemment être attribués à des dinosaures théropodes. L’étude des dents isolées montre que les dinosaures étaient déjà bien diversifiés en Europe occidentale à la fin du Trias.
Depuis la découverte, en 1878, des célèbres
Trois morphotypes dentaires peuvent prudemment être rapprochés des dinosaures ornithischiens sur la base de la combinaison de plusieurs caractères, tels que la couronne basse et triangulaire, la présence d’une constriction bien marquée entre la racine et la couronne, la présence de gros denticules formant un angle de 45° avec le bord de la couronne, ou encore l’asymétrie de la couronne en vue mésiale ou distale
Le premier morphotype dentaire (Fig. 1) ressemble beaucoup aux spécimens décrits comme des dents prémaxillaires distales d’
IRSNB R211 (Fig. 4) présente une série de caractères habituellement considérés comme synapomorphiques pour les Eusauropoda : couronne de forme spatulée, émail dentaire finement plissé et facettes occlusales bien développées
Certaines dents trouvées à Saint-Nicolas-de-Port rappellent celles des dinosaures théropodes : elles sont caniniformes et leurs carènes portent des crénelures bien marquées. Cependant, de tels types de dents peuvent également, au Trias supérieur, être observés dans d’autres lignées indépendantes d’Archosauriformes
Les dents les plus courantes (Fig. 6) ressemblent beaucoup à celles rapportées à
Bien que leurs fossiles soient relativement rares à Habay-la-Vieille, les dinosaures apparaissent bien diversifiés, indiquant que les principaux groupes de dinosaures étaient déjà bien implantés en Europe occidentale à la fin du Trias. C’est particulièrement le cas pour les petits ornithischiens, également connus dans plusieurs localités d’Allemagne, de France et du grand-duché de Luxembourg
Si l’étude des dents isolées de dinosaures est souvent frustrante, à cause de l’impossibilité d’établir des identifications précises, particulièrement dans des sédiments datés du Trias supérieur, elle apporte cependant de précieuses informations sur la biodiversité réelle de ces animaux à une période donnée. Il est regrettable que de telles recherches sur les microrestes de dinosaures du Trias supérieur n’aient pas encore été tentées systématiquement en dehors de l’Europe occidentale et de l’Amérique du Nord.
In March 1878, coal miners uncovered pieces of dinosaur bones deep in an underground mine called the Sainte-Barbe pit, near Bernissart in western Belgium. It was the beginning of one of the greatest dinosaur discoveries of all times: more than 30 complete, articulated skeletons of the Early Cretaceous ornithopod
Herein we describe some isolated dinosaur teeth recently found in the Late Triassic of Habay-la-Vieille, southern Belgium. Since the early 1980s, sediments from this locality have been intensively screen-washed and have provided numerous vertebrate micro-remains
All specimens described herein are housed in the palaeontological collections of the ‘Institut royal des Sciences naturelles de Belgique’ (IRSNB).
The following teeth are tentatively referred to the ornithischian dinosaurs, because they present a combination of the following characters
IRSNB R208 closely resembles specimens described as distal premaxillary teeth of
IRSNB R209 resembles specimens described as caudal cheek teeth of
IRSNB R210 is triangular in outline, slightly higher than long and very narrow. The crown is slightly curved backward and inward. The labial side is more convex than the lingual one. Both mesial and distal edges bear a dozen very small denticles, arranged at about 45° to the edges of the crown. Because they are so worn, it is not possible to know whether or not these denticles reached the base of the crown. Several delicate ridges ornament the lingual side of the crown.
A very similar tooth was described from the Late Triassic of Saint-Nicolas-de-Port, northeastern France
The root of IRSNB R211 is broken off; it is rounded in cross-section and separated from the crown by a slight constriction. The crown is typically spatulate. It is rather mesio-distally expanded, with a convex labial side and a slightly concave lingual side. The distal part of the crown therefore has a D-shaped cross-section. The surface texture of the enamel is wrinkled. The labial side of the crown bears one shallow vertical groove along its mesial margin. This character indicates an imbricate arrangement of adjacent teeth: this gentle groove accommodated the lingual aspect of the distal margin of the next anteriormost tooth. An extended V-shaped wear facet is developed along the mesial and distal edges of the crown. Such a wear facet suggests precise interlocking occlusion. Although they are extremely eroded because of wear, denticles were apparently developed along both margins of the crown.
This tooth displays a number of characters usually regarded as synapomorphic for Eusauropoda
The crown of IRSNB R212 is labio-lingually compressed, higher than long, and slightly recurved backwards and inwards. Both carinae bear about 15 coarse denticles, set at about 45° to the edges. The labial side of the crown is smoothly convex mesio-distally, whereas depressed areas separate the carinae from the middle part of the crown on the lingual side of the crown. The enamel is wrinkled on both sides. The tip of the crown bears a small rounded abrasion facet. Crown and root are not separated by a marked constriction. The root is elliptical in cross-section.
Similar teeth have been described in the Upper Triassic of Saint-Nicolas-de-Port, in northeastern France
The following teeth closely resemble those of theropod dinosaurs: they are caniniform, recurved backwards and their carinae bear serrations. However, it must be noted that, in Late Triassic times, such a dental morphology can also be observed in several independent lineages of Late Triassic Archosauriformes
Several shed teeth of this morphotype have been found at Habay-la-Vielle. IRSNB R213 is by far the largest and best preserved of the series. The crown is caniniform, curved backwards and strongly compressed labio-lingually. The lingual side is slightly more convex than the labial one. The distal carina bears well-developed rectangular serrations (around 5 per millimetre) all along the height of the crown. The serrations are perpendicular to the carina. The mesial carina forms a cutting edge near the apex of the crown and gradually becomes rounded towards the root. Serrations are present along the apical two thirds of the mesial edge; they are slightly smaller than the distal serrations. The enamel is not smooth, but gently wrinkled on both sides of the crown.
Such teeth closely resemble those of the ceratosaur
Two specimens significantly differ from the typical
Although dinosaur remains are rare at Habay-la-Vieille, they appear well diversified, suggesting that the major dinosaur groups were well established in Europe since the end of the Triassic. The small size of the dinosaur fossils collected at Habay-la-Vieille probably has a taphonomic rather than an ecologic explanation. The vertebrate assemblage from this locality is a mixture of terrestrial and marine forms. The marine vertebrates are by far dominant within the Habay-la-Vieille bonebeds, represented to date by several thousands fossils of all sizes. Although very diversified, the terrestrial component of the bonebeds represents only a few percents of the recovered specimens. All the fossils of terrestrial vertebrates are of small size. Such vertebrate assemblage is characteristic for littoral or subtidal deposits, as also suggested by sedimentological studies of the locality
Small ornithischian dinosaurs are known from Carnian and Norian deposits in North and South America
The study of isolated sauropodomorph teeth from Habay-la-Vieille substantiates that sauropods were already present in Western Europe at the end of the Triassic. They co-existed with prosauropods, but occupied different ecological niches. Whereas sauropod teeth are adapted for an herbivorous diet
The study of Late Triassic dinosaur teeth is especially frustrating because of the impossibility for detailed determinations based on such an incomplete material. However, it produces accurate information about the real dinosaur biodiversity during this period. For that reason, it is disappointing that the search for dinosaur and other vertebrate micro-remains has not been systematically attempted to date in Late Triassic terrestrial deposits outside western Europe and North America. This would be particularly welcome in Gondwana, where small Mesozoic tetrapods are under-represented in fossil collections.
The authors are very grateful to D. Delsate and H. Huygens, for allowing them to examine their collections. J.-J. Blairvacq, S. Clinet, and H. De Potter participated in the screen-washing and sorting under binocular of the studied material. Julien Cillis produced the photographs. K. Padian and one anonymous reviewer kindly made helpful comments on the manuscript. P. Godefroit’s work was supported by a grant from the SSTC-DWTC.
Dinosaur teeth from the Upper Triassic of Habay-la-Vieille (southern Belgium).
Fig. 1. Dents de dinosaures du Trias supérieur d’Habay-la-Vieille (Sud de la Belgique).
Ornithischia indet. morphotype 2 (IRSNB R209), labial view.
Fig. 2. Ornithischia indet. morphotype 2 (IRSNB R209), vue labiale.
Ornithischia indet. morphotype 3 (IRSNB R210), lingual view.
Fig. 3. Ornithischia indet. morphotype 3 (IRSNB R210), vue linguale.
Eusauropoda indet. (IRSNB R211),
Fig. 4. Eusauropoda indet. (IRSNB R211),
Prosauropoda indet. (IRSNB R212), lingual view.
Fig. 5. Prosauropoda indet. (IRSNB R212), vue linguale.
Theropoda indet. morphotype 1 (IRSNB R213),
Fig. 6. Theropoda indet. morphotype 1 (IRSNB R213),
Theropoda indet. morphotype 2 (IRSNB R214),
Fig. 7. Theropoda indet. morphotype 2 (IRSNB R214),