Sources of evidence available in the fossil record to determine the diet of dinosaurs
Bonjour tout le monde,
Parce que je trouve que ces derniers temps, ca manque un peu de post scientifiques sur les dinosaures, j'ai descidé de "publier" deux travaux que j'ai pu réaliser dernièrement sur les dinosaures. Le premier concerne l'alimentation des "terribles lézards", le second (dans un autre post) concerne les recherches qui ont été faites et qui pourraient être menées sur les Spinosauridae dans le cadre d'une étude bioméchanique.
C'est en anglais, je m'en excuse (études en anglais oblige). Je n'ai pas le courage de traduire tout cela en français. Mais c'est un excellent moyen pour ceux qui désirent devenir paléontologue, de lire un peu d'anglais, surtout quand cela concerne les dinosaures.
Voilà, j'ignore si cela va vous intéresser, j'espère en tout cas que ces deux textes apprendront à ceux qui les liront des choses nouvelles sur les dinosaures.
A bientôt...
Nekar
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Edité le 27/01/2008 à 13:10 par Nekarius
Discussion:
115 820
13
Dernière réponse
115 820
13
Dernière réponse
Posté par Nekarius
Posté par Nekarius
Introduction
Dinosaurs were a very successful group of animals which arose in the Late Triassic and dominated terrestrial faunas for the next 165 Myr until their extinction at the end of the Cretaceous (65 Myr ago). They were extremely diversified because they include forms from small turkey-like animals to giant herbivores of more than 80 tones (Benton 2005). They evolutionary success partly results from their feeding adaptation. Indeed, dinosaurs include carnivorous, herbivorous, piscivorous, insectivorous and omnivorous animals which possess a large variety of skull adapted to a large range of food (Weishampel et al. 2004). From the first discoveries of dinosaurs, the diet of these animals has filled with enthusiasm scientists and nowadays feeding is probably the most discussed mode of dinosaur behaviour amongst them (Martin 2001). Here is presented all pieces of evidence available in the fossil record that are used to figure out what food dinosaurs ate, from indirect ones that include gastroliths, tooth shape and theories about foraging abilities inferred from functional morphology to direct evidence which results from all stages of feeding behavior, including search, captures, ingestion, digestion and defecation. Clues of direct evidence have been gleaned from a variety of trace fossils (tracks, tooth marks, gastroliths, regurgitalithes and coprolites) and from distinctive assemblage of skeletal material and stomach contents (Chin 1997).
Indirect evidence
Speculations about dinosaur diets are frequently based on indirect evidence. Such analyses are important tools that have suggested generalized dinosaur feeding strategies. However, indirect evidence cannot tell us which available foods were actually eaten. Indirect evidence of dinosaur's diet includes deductions on skull, teeth and other skeletal components morphology and gastroliths.
I. Dinosaur teeth morphology.
In most dinosaurs, dentition was composed of individual teeth that were similarly shaped (Isodonty). Large, recurved, and serrated teeth called ziphodont (fig. I D and E) is designed for grasping and cutting through flesh, as well as crushing or punching though bones. They constitute a common anatomical attribute of most theropod dinosaurs which were therefore meat-eaters. Most of theropod had bladed ziphodont teeth (fig. I D) but a few ones such as spinosaurs had teeth typically elongate, conical and recurved (fig. I E) which have led to the hypothesis that these animals were piscivorous.
On the other hand, leaf-like, spatulate and peg-like (cylindrical) teeth shape characterize herbivorous dinosaur. Those teeth were functional for grasping, tearing, shearing, and grinding plant material. Peg-like (fig. I B) and spatulate teeth (fig. I C) are a hallmark of sauropod dinosaurs which used them mainly for pulling plan material into their mouths, followed by swallowing without chewing. Leaf-shaped teeth (fig. I A) with coarse serrations are present in prosauropods, some theropods (therizinosaurids) and most of ornithischian dinosaurs and indicate a cutting ability that was specifically adapted for separating plant material from trunks, stems, or roots.
Heterodont dentition is seen in some dinosaurs such as one of the oldest know dinosaur Eoraptor and two clade of ornithischian dinosaurs, the Heterodontosauridae and the Pachycephalosauridae. However, these animals are not seen as omnivorous contrary to some theropod such as troodontids which possessed teeth with coarse serration (Holtz et al. 1998).
II. Other skeletal components morphology.
The morphology of the skull can give precious information on the dinosaur diet as well.
- Presence of a horn covered beak or bill in Marginocephalia (fig. II B), Thyreophora and Ornithopoda (fig. II A) is a clear adaptation for a diet plant because it would have allowed cropping plants and grabbing swaths of vegetation. Few theropod dinosaurs such as some Ornithomimidae (fig. II C) and Oviraptosauria lack teeth and have had beaks as well. There may have been therefore omnivorous, herbivorous, or insectivorous (Norman 2003, Martin 2001).
- The majority of ornithischian dinosaurs have a very distinctive depression or recess running along the side of the face adjacent and parallel to the teeth along the jaws. It is now generally agreed that these recesses correspond to the position of fleshy cheeks that have permitted to temporarily store plant material in their mouths for thorough chewing and avoid the risk of continually losing food from the side of the mouth with each bite. There is good structural evidence that some ornithischian dinosaur developed the ability to chew plant prior to swallowing it. Indeed, detailed analysis of the structure of the skull of some ornithopods has revealed a mechanical arrangement that allows the upper jaws to hinge outward against the skull roof in a mechanism named pleurokinesis (Norman 2003).
- The global aspect of the skull can also reveal the diet of dinosaurs as well. The Tyrannosauridae, Allosauridae (fig. IV A) and Carcharodontosauridae had a massive head, large and extremely strongly built. They were super predators which have been able to prey upon other dinosaurs and dismember those (Norman 2003). On the other hand, Spinosauridae possessed a long head with an elongated and narrow snout (fig. IV B). This slender crocodile-like skull has been probably adapted to a piscivorous feeding and was not able to dismember large herbivorous dinosaurs (Martin 2001).
- Some ornithopods and ceratopsians have had dental batteries, in which the teeth in the cheek region were fused together to form "compound teeth". The most complex dental batteries known are those of hadrosaurids (fig. III A and B). This arrangement of the teeth composed a tool for increasing the surface area of tough plant to grinding and therefore they were clearly adapted for eating large amount of plant material (Martin 2001).
Some part of the postcranial skeleton can bring some information on what dinosaurs should have eaten. The extremely long sauropodomorph neck, which can be compared to the giraffe, is probably an adaptation for gaining access to increasingly taller treetops of conifers. Some carnivorous dinosaurs have developed claws in order to hunt easily their prey. It is the case of the well-know dromaeosaurids which had a sharp, retractable ungual on digit II of the foot (fig. V A). This claw strongly suggests that it had an offensive purpose, such as disembowelling prey animals (Martin 2001). The long harm ended with well-developed hook-like claws (Fig. V B) is another support of the ichthyophagy of the Spinosauridae because this claw were interpreted to be used for 'gaffing' fish out of the water (Charig & Milner 1997).
III. Gastroliths
Some dinosaurs apparently ingested stones called gastroliths which were retained in the digestive tract. These may have functioned to aid digestion by one of two means. Classically, the muscular activity of the stomach is supposed to have caused the stones to bounce against each other, thereby crushing the trapped plant material. Alternatively, the stones may have served to mix up the contents of the stomach, ensuring more complete digestion of its contents. It is also possible that the tough plant material was broken within a gizzard-like structure, or even within a muscular crop, although evidence for the soft part is not found in the fossil record (Tiffney, 1997). Dinosaurs with well supported evidence for gastroliths include some sauropodomorphs, nodosaurids, psittacosaurids (fig. VI A), some ornithopods (Iguanodon and Edmontosaurus) and a few theropods such as ornithomimosaurs and Caudipteryx (fig. VI B). New researches on gastroliths argue against the presence of a gastric mill in sauropods but gastrolith clusters of some derived theropod dinosaurs (oviraptorosaurs and ornithomimosaurs) compare well with those of birds, suggesting that the gastric mill evolved in the avian stem lineage (Wings & Sanders 2007).
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Edité le 27/01/2008 à 13:10 par Nekarius
Dinosaurs were a very successful group of animals which arose in the Late Triassic and dominated terrestrial faunas for the next 165 Myr until their extinction at the end of the Cretaceous (65 Myr ago). They were extremely diversified because they include forms from small turkey-like animals to giant herbivores of more than 80 tones (Benton 2005). They evolutionary success partly results from their feeding adaptation. Indeed, dinosaurs include carnivorous, herbivorous, piscivorous, insectivorous and omnivorous animals which possess a large variety of skull adapted to a large range of food (Weishampel et al. 2004). From the first discoveries of dinosaurs, the diet of these animals has filled with enthusiasm scientists and nowadays feeding is probably the most discussed mode of dinosaur behaviour amongst them (Martin 2001). Here is presented all pieces of evidence available in the fossil record that are used to figure out what food dinosaurs ate, from indirect ones that include gastroliths, tooth shape and theories about foraging abilities inferred from functional morphology to direct evidence which results from all stages of feeding behavior, including search, captures, ingestion, digestion and defecation. Clues of direct evidence have been gleaned from a variety of trace fossils (tracks, tooth marks, gastroliths, regurgitalithes and coprolites) and from distinctive assemblage of skeletal material and stomach contents (Chin 1997).
Indirect evidence
Speculations about dinosaur diets are frequently based on indirect evidence. Such analyses are important tools that have suggested generalized dinosaur feeding strategies. However, indirect evidence cannot tell us which available foods were actually eaten. Indirect evidence of dinosaur's diet includes deductions on skull, teeth and other skeletal components morphology and gastroliths.
I. Dinosaur teeth morphology.
In most dinosaurs, dentition was composed of individual teeth that were similarly shaped (Isodonty). Large, recurved, and serrated teeth called ziphodont (fig. I D and E) is designed for grasping and cutting through flesh, as well as crushing or punching though bones. They constitute a common anatomical attribute of most theropod dinosaurs which were therefore meat-eaters. Most of theropod had bladed ziphodont teeth (fig. I D) but a few ones such as spinosaurs had teeth typically elongate, conical and recurved (fig. I E) which have led to the hypothesis that these animals were piscivorous.
On the other hand, leaf-like, spatulate and peg-like (cylindrical) teeth shape characterize herbivorous dinosaur. Those teeth were functional for grasping, tearing, shearing, and grinding plant material. Peg-like (fig. I B) and spatulate teeth (fig. I C) are a hallmark of sauropod dinosaurs which used them mainly for pulling plan material into their mouths, followed by swallowing without chewing. Leaf-shaped teeth (fig. I A) with coarse serrations are present in prosauropods, some theropods (therizinosaurids) and most of ornithischian dinosaurs and indicate a cutting ability that was specifically adapted for separating plant material from trunks, stems, or roots.
Heterodont dentition is seen in some dinosaurs such as one of the oldest know dinosaur Eoraptor and two clade of ornithischian dinosaurs, the Heterodontosauridae and the Pachycephalosauridae. However, these animals are not seen as omnivorous contrary to some theropod such as troodontids which possessed teeth with coarse serration (Holtz et al. 1998).
II. Other skeletal components morphology.
The morphology of the skull can give precious information on the dinosaur diet as well.
- Presence of a horn covered beak or bill in Marginocephalia (fig. II B), Thyreophora and Ornithopoda (fig. II A) is a clear adaptation for a diet plant because it would have allowed cropping plants and grabbing swaths of vegetation. Few theropod dinosaurs such as some Ornithomimidae (fig. II C) and Oviraptosauria lack teeth and have had beaks as well. There may have been therefore omnivorous, herbivorous, or insectivorous (Norman 2003, Martin 2001).
- The majority of ornithischian dinosaurs have a very distinctive depression or recess running along the side of the face adjacent and parallel to the teeth along the jaws. It is now generally agreed that these recesses correspond to the position of fleshy cheeks that have permitted to temporarily store plant material in their mouths for thorough chewing and avoid the risk of continually losing food from the side of the mouth with each bite. There is good structural evidence that some ornithischian dinosaur developed the ability to chew plant prior to swallowing it. Indeed, detailed analysis of the structure of the skull of some ornithopods has revealed a mechanical arrangement that allows the upper jaws to hinge outward against the skull roof in a mechanism named pleurokinesis (Norman 2003).
- The global aspect of the skull can also reveal the diet of dinosaurs as well. The Tyrannosauridae, Allosauridae (fig. IV A) and Carcharodontosauridae had a massive head, large and extremely strongly built. They were super predators which have been able to prey upon other dinosaurs and dismember those (Norman 2003). On the other hand, Spinosauridae possessed a long head with an elongated and narrow snout (fig. IV B). This slender crocodile-like skull has been probably adapted to a piscivorous feeding and was not able to dismember large herbivorous dinosaurs (Martin 2001).
- Some ornithopods and ceratopsians have had dental batteries, in which the teeth in the cheek region were fused together to form "compound teeth". The most complex dental batteries known are those of hadrosaurids (fig. III A and B). This arrangement of the teeth composed a tool for increasing the surface area of tough plant to grinding and therefore they were clearly adapted for eating large amount of plant material (Martin 2001).
Some part of the postcranial skeleton can bring some information on what dinosaurs should have eaten. The extremely long sauropodomorph neck, which can be compared to the giraffe, is probably an adaptation for gaining access to increasingly taller treetops of conifers. Some carnivorous dinosaurs have developed claws in order to hunt easily their prey. It is the case of the well-know dromaeosaurids which had a sharp, retractable ungual on digit II of the foot (fig. V A). This claw strongly suggests that it had an offensive purpose, such as disembowelling prey animals (Martin 2001). The long harm ended with well-developed hook-like claws (Fig. V B) is another support of the ichthyophagy of the Spinosauridae because this claw were interpreted to be used for 'gaffing' fish out of the water (Charig & Milner 1997).
III. Gastroliths
Some dinosaurs apparently ingested stones called gastroliths which were retained in the digestive tract. These may have functioned to aid digestion by one of two means. Classically, the muscular activity of the stomach is supposed to have caused the stones to bounce against each other, thereby crushing the trapped plant material. Alternatively, the stones may have served to mix up the contents of the stomach, ensuring more complete digestion of its contents. It is also possible that the tough plant material was broken within a gizzard-like structure, or even within a muscular crop, although evidence for the soft part is not found in the fossil record (Tiffney, 1997). Dinosaurs with well supported evidence for gastroliths include some sauropodomorphs, nodosaurids, psittacosaurids (fig. VI A), some ornithopods (Iguanodon and Edmontosaurus) and a few theropods such as ornithomimosaurs and Caudipteryx (fig. VI B). New researches on gastroliths argue against the presence of a gastric mill in sauropods but gastrolith clusters of some derived theropod dinosaurs (oviraptorosaurs and ornithomimosaurs) compare well with those of birds, suggesting that the gastric mill evolved in the avian stem lineage (Wings & Sanders 2007).
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Edité le 27/01/2008 à 13:10 par Nekarius
Posté par Nekarius
Direct evidence
I. Tracks
Track ways are evidence of the search of food. The act of looking for food might seems to be untraceable but animal occasionally left sets of tracks that strongly suggest they were actively seeking food. It is the case with some dinosaur track ways and one of the most famous is the Early Cretaceous site along the Paluxy River in Texas (fig. VII) where appears tracks from one theropod (probably an Acrocanthosaurus) running parallel to the trail left by a sauropod (most likely a Pleurocoelus), which was apparently travelling in a herd (Chin 1997; Thomas & Farlow 2003). Detailed analysis of the track ways shows that the proximity of the two sets of tracks could not have resulted from the walk of two dinosaurs which had taken similar routes because both were following an ancient shoreline. It seems most likely that the carnivorous dinosaur was following the herbivore (Thomas & Farlow 2003). Fossil tracks have also provided information about the foraging behaviour of herbivorous dinosaurs. Indeed, a set of footprints in the roof of a Utah coal mine where found clustered around fossil tree trunks that were preserved in growth position. The tracks are oriented toward the tree trunks and suggest the shuffling steps of browsing hadrosaurs (Chin 1997).
II. Fossil assemblage
Some exceptional fossil assemblages which include the associations of different organisms can be an excellent source on predator/prey interaction. One of the most famous associations between a predator and its prey in the fossil record is the fight between the meet-eater Velociraptor entangled with the herbivorous Protoceratops (fig. VIII A) and discovered in the Upper Cretaceous Mongolian sandstones. The relative positions of the two dinosaurs suggest they were engaged in a struggle when they died. Indeed, the theropod's clawed feet extend into the Protoceratops's throat and the Velociraptor arm is firmly locked in the herbivore's jaws (Chin 1997).
Other predator/prey relationships are suggested by associations of theropod teeth with bones from other animals. Some rare fossil specimens show a theropod tooth directly embedded in a bone. This is the case of a remarkable Hypacrosaurus (ornithopod) fibula with a tyrannosaurid tooth embedded within it (Farlow & Holtz 2002), a pterosaur cervical vertebra perforated by a spinosaurid tooth (fig. VIII B, Buffetaut et al. 2004) and a broken troodontid tooth similarly associated with a pterosaur tibia (Currie & Jacobsen 1995) demonstrating that pterosaurs were part of the theropod diet.
Several theropod feeding site indicated by the association of several theropod teeth with herbivorous dinosaurs are know from the Upper Jurassic of Thailand (Buffetaut & Suteethorn 1989) and the Lower Cretaceous of Montana, where fifteen different sites were found to have Deinonychus teeth associated with Tenontosaurus (ornithopod) bones (Chin 1997).
III. Tooth Marks
Tooth-damaged dinosaur bone can be recognized by distinctive markings such as groove or punctures. Although some damage may have been inflicted during intraspecific dominance fights, most bite marks probably indicate carnivory. Identification of damaged bone can tell us that a particular species of dinosaur was eaten, but it does not indicate whether the prey was hunted and killed or scavenged. The identity of the animal responsible for bite arks is usually difficult to determine but some well-preserved tooth marks can occasionally exhibit distinctive shapes, spacing, and/or serration marks that allow comparisons with fossil jaws of contemporaneous carnivores (Chin 1997). Some reported examples from the Late Cretaceous include Troodon tooth marks in ceratopsians bones, Saurornitholestes tooth marks in bones of an ornithomimid and Edmontosaurus, and Tyrannosaurus tooth marks in ceratopsian, hadrosaurid such as Edmontosaurus (Fig. IX B), and Saurornitholestes bones (Martin 2001). A sample of tooth-marked dinosaur bone (Fig. IX A) recovered from the Upper Cretaceous of Madagascar has revealed that the theropod Majungatholus was a cannibal (Rogers et al. 2003).
IV. Stomach Contents
Of all data relating to what dinosaur ate, few are as unambiguous and convincing as stomach contents. However, considering that fossilization is a rare event, finding a partially digested last meal in the gut region of a fossilized animal such as a dinosaur is exceptional. Furthermore, it would require the excellent preservation of an articulated specimen that had been undisturbed by erosion or scavenging (Chin 1997). Amongst the herbivorous dinosaurs, there is solid evidence that gut contents were preserved within the ankylosaur Minmi skeleton which was composed exclusively of angiosperm fruits and a Brachylophosaurus (ornithopod) carcass. The evidence for a handful of reports of possible Edmontosaurus (ornithopod) gut contents is equivocal; in most cases it seems to be equally likely that plant matter in the gut regions of these carcasses was introduced hydrodynamically (Chin 2007). Reports of carnivore stomach contents are more convincing. A Compsognathus specimen (fig. X B) from the Late Jurassic Solnhofen of Germany contained a complete specimen of Bavarisaurus (a lizard) in its stomach region. Two articulated skeletons of the Triassic dinosaur Coelophysis were found to have skeletal remains from other Coelophysis within their thoracic cavities and therefore revealed that these dinosaurs engaged in cannibalism (fig. X A). The feathered dinosaur Sinosauropteryx from the Early Cretaceous of China contains an unidentified small mammal that is only present as a single dentary. An acid-etched vertebra from a juvenile hadrosaur was found with the partial remains of the tyrannosaurid Daspletosaurus (Martin 2001) and acid-etched scales and teeth of the fish Lepidotes and the disarticulated skeletal remains of a young Iguanodon were found in the stomach region of the spinosaurid Baryonyx (Charig & Milner, 1997).
V. Regurgitaliths
The fossilized remains of stomach contents that has been regurgitated by an animal (regurgitaliths) might provide useful information on the diet of the animal such as stomach contents, although they are difficult to relate to any particular species and their preservation potential is very low. Only one dinosaur regurgitate, found in Early Cretaceous deposits of Mongolia and composed of turtle and dinosaur bones fragments, has been interpreted as such (Martin 2001). A regurgitated pellet containing four juvenile birds has been discovered in the Early Cretaceous of Spain (Fig. XI) and the most likely predator to have produced this pellet is either a small theropod dinosaur or a pterosaur that hunted different prey, swallowed them whole and then regurgitated the indigestible remains, much as owls do today (Sanz et al. 2001).
VI. Coprolites
Coprolites are fossilized remains of the solid or semi-solid fecal material produced by an animal (Martin 2001). Because feces are the unutilized waste product of digestion, they literally provide the end of food habits. Studies on the diets of extant animals often rely on fecal analyses because many dietary components are still identifiable after passage though an animal's dung. Indeed, coprolites may contain body fossils, such as bacteria, plant fragments or bones, or in very rare cases may contain soft tissues. Contrary to coprolite produced by aquatic organisms that lived in environment that were subject to rapid sedimentation, fecal matter deposit on land such as those made by dinosaurs, is less likely to be preserved because it is vulnerable to decomposition, desiccation, trampling, erosion, and coprophagy. Recognizing possible dinosaur coprolite can be also problematic, especially since many vertebrates produce similarly shaped faces. Fortunately, large fecal volume can only be generated by large dinosaurs (Chin 1997). In that manner, a king-sized coprolite (Fig. XII A) containing a high proportion of bone fragment has been identified to be produced by a tyrannosaurid, probably Tyrannosaurus rex (Chin et al. 1998). Exceptionally detailed soft tissues containing undigested muscle tissue have been identified within the fossilized feces of another large Cretaceous tyrannosaurid (Chin et al. 2003). Titanosaur (sauropod) coprolites from Indian which contain silicified plant tissues have revealed that different taxa from extant grass were present on the Indian subcontinent during the latest Cretaceous (Prasad et al. 2005). Recently, rare assemblages of woody coprolites from Montana attributed to ornithopod Maiasaura (fig. XII B) indicated a highly fibrous diet with a dietary preference for conifers (Chin 2007).
Conclusion
Despite the ancient nature of diet, indirect and direct evidence of dinosaur feeding activity has been gleaned from a surprising variety of fossil source. Teeth and skull morphology, exceptional track ways, skeletal assemblages, tooth marks, stomach contents, gastroliths, regurgitaliths and coprolites have provided bits and pieces of information that help reveal feeding traces or specific food items. Some of these finds help confirm previous speculations about dinosaur herbivory or predator/prey interactions, while others bolster arguments for feeding strategies such as a pack hunting or cannibalism.
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Edité le 27/01/2008 à 12:55 par Nekarius
I. Tracks
Track ways are evidence of the search of food. The act of looking for food might seems to be untraceable but animal occasionally left sets of tracks that strongly suggest they were actively seeking food. It is the case with some dinosaur track ways and one of the most famous is the Early Cretaceous site along the Paluxy River in Texas (fig. VII) where appears tracks from one theropod (probably an Acrocanthosaurus) running parallel to the trail left by a sauropod (most likely a Pleurocoelus), which was apparently travelling in a herd (Chin 1997; Thomas & Farlow 2003). Detailed analysis of the track ways shows that the proximity of the two sets of tracks could not have resulted from the walk of two dinosaurs which had taken similar routes because both were following an ancient shoreline. It seems most likely that the carnivorous dinosaur was following the herbivore (Thomas & Farlow 2003). Fossil tracks have also provided information about the foraging behaviour of herbivorous dinosaurs. Indeed, a set of footprints in the roof of a Utah coal mine where found clustered around fossil tree trunks that were preserved in growth position. The tracks are oriented toward the tree trunks and suggest the shuffling steps of browsing hadrosaurs (Chin 1997).
II. Fossil assemblage
Some exceptional fossil assemblages which include the associations of different organisms can be an excellent source on predator/prey interaction. One of the most famous associations between a predator and its prey in the fossil record is the fight between the meet-eater Velociraptor entangled with the herbivorous Protoceratops (fig. VIII A) and discovered in the Upper Cretaceous Mongolian sandstones. The relative positions of the two dinosaurs suggest they were engaged in a struggle when they died. Indeed, the theropod's clawed feet extend into the Protoceratops's throat and the Velociraptor arm is firmly locked in the herbivore's jaws (Chin 1997).
Other predator/prey relationships are suggested by associations of theropod teeth with bones from other animals. Some rare fossil specimens show a theropod tooth directly embedded in a bone. This is the case of a remarkable Hypacrosaurus (ornithopod) fibula with a tyrannosaurid tooth embedded within it (Farlow & Holtz 2002), a pterosaur cervical vertebra perforated by a spinosaurid tooth (fig. VIII B, Buffetaut et al. 2004) and a broken troodontid tooth similarly associated with a pterosaur tibia (Currie & Jacobsen 1995) demonstrating that pterosaurs were part of the theropod diet.
Several theropod feeding site indicated by the association of several theropod teeth with herbivorous dinosaurs are know from the Upper Jurassic of Thailand (Buffetaut & Suteethorn 1989) and the Lower Cretaceous of Montana, where fifteen different sites were found to have Deinonychus teeth associated with Tenontosaurus (ornithopod) bones (Chin 1997).
III. Tooth Marks
Tooth-damaged dinosaur bone can be recognized by distinctive markings such as groove or punctures. Although some damage may have been inflicted during intraspecific dominance fights, most bite marks probably indicate carnivory. Identification of damaged bone can tell us that a particular species of dinosaur was eaten, but it does not indicate whether the prey was hunted and killed or scavenged. The identity of the animal responsible for bite arks is usually difficult to determine but some well-preserved tooth marks can occasionally exhibit distinctive shapes, spacing, and/or serration marks that allow comparisons with fossil jaws of contemporaneous carnivores (Chin 1997). Some reported examples from the Late Cretaceous include Troodon tooth marks in ceratopsians bones, Saurornitholestes tooth marks in bones of an ornithomimid and Edmontosaurus, and Tyrannosaurus tooth marks in ceratopsian, hadrosaurid such as Edmontosaurus (Fig. IX B), and Saurornitholestes bones (Martin 2001). A sample of tooth-marked dinosaur bone (Fig. IX A) recovered from the Upper Cretaceous of Madagascar has revealed that the theropod Majungatholus was a cannibal (Rogers et al. 2003).
IV. Stomach Contents
Of all data relating to what dinosaur ate, few are as unambiguous and convincing as stomach contents. However, considering that fossilization is a rare event, finding a partially digested last meal in the gut region of a fossilized animal such as a dinosaur is exceptional. Furthermore, it would require the excellent preservation of an articulated specimen that had been undisturbed by erosion or scavenging (Chin 1997). Amongst the herbivorous dinosaurs, there is solid evidence that gut contents were preserved within the ankylosaur Minmi skeleton which was composed exclusively of angiosperm fruits and a Brachylophosaurus (ornithopod) carcass. The evidence for a handful of reports of possible Edmontosaurus (ornithopod) gut contents is equivocal; in most cases it seems to be equally likely that plant matter in the gut regions of these carcasses was introduced hydrodynamically (Chin 2007). Reports of carnivore stomach contents are more convincing. A Compsognathus specimen (fig. X B) from the Late Jurassic Solnhofen of Germany contained a complete specimen of Bavarisaurus (a lizard) in its stomach region. Two articulated skeletons of the Triassic dinosaur Coelophysis were found to have skeletal remains from other Coelophysis within their thoracic cavities and therefore revealed that these dinosaurs engaged in cannibalism (fig. X A). The feathered dinosaur Sinosauropteryx from the Early Cretaceous of China contains an unidentified small mammal that is only present as a single dentary. An acid-etched vertebra from a juvenile hadrosaur was found with the partial remains of the tyrannosaurid Daspletosaurus (Martin 2001) and acid-etched scales and teeth of the fish Lepidotes and the disarticulated skeletal remains of a young Iguanodon were found in the stomach region of the spinosaurid Baryonyx (Charig & Milner, 1997).
V. Regurgitaliths
The fossilized remains of stomach contents that has been regurgitated by an animal (regurgitaliths) might provide useful information on the diet of the animal such as stomach contents, although they are difficult to relate to any particular species and their preservation potential is very low. Only one dinosaur regurgitate, found in Early Cretaceous deposits of Mongolia and composed of turtle and dinosaur bones fragments, has been interpreted as such (Martin 2001). A regurgitated pellet containing four juvenile birds has been discovered in the Early Cretaceous of Spain (Fig. XI) and the most likely predator to have produced this pellet is either a small theropod dinosaur or a pterosaur that hunted different prey, swallowed them whole and then regurgitated the indigestible remains, much as owls do today (Sanz et al. 2001).
VI. Coprolites
Coprolites are fossilized remains of the solid or semi-solid fecal material produced by an animal (Martin 2001). Because feces are the unutilized waste product of digestion, they literally provide the end of food habits. Studies on the diets of extant animals often rely on fecal analyses because many dietary components are still identifiable after passage though an animal's dung. Indeed, coprolites may contain body fossils, such as bacteria, plant fragments or bones, or in very rare cases may contain soft tissues. Contrary to coprolite produced by aquatic organisms that lived in environment that were subject to rapid sedimentation, fecal matter deposit on land such as those made by dinosaurs, is less likely to be preserved because it is vulnerable to decomposition, desiccation, trampling, erosion, and coprophagy. Recognizing possible dinosaur coprolite can be also problematic, especially since many vertebrates produce similarly shaped faces. Fortunately, large fecal volume can only be generated by large dinosaurs (Chin 1997). In that manner, a king-sized coprolite (Fig. XII A) containing a high proportion of bone fragment has been identified to be produced by a tyrannosaurid, probably Tyrannosaurus rex (Chin et al. 1998). Exceptionally detailed soft tissues containing undigested muscle tissue have been identified within the fossilized feces of another large Cretaceous tyrannosaurid (Chin et al. 2003). Titanosaur (sauropod) coprolites from Indian which contain silicified plant tissues have revealed that different taxa from extant grass were present on the Indian subcontinent during the latest Cretaceous (Prasad et al. 2005). Recently, rare assemblages of woody coprolites from Montana attributed to ornithopod Maiasaura (fig. XII B) indicated a highly fibrous diet with a dietary preference for conifers (Chin 2007).
Conclusion
Despite the ancient nature of diet, indirect and direct evidence of dinosaur feeding activity has been gleaned from a surprising variety of fossil source. Teeth and skull morphology, exceptional track ways, skeletal assemblages, tooth marks, stomach contents, gastroliths, regurgitaliths and coprolites have provided bits and pieces of information that help reveal feeding traces or specific food items. Some of these finds help confirm previous speculations about dinosaur herbivory or predator/prey interactions, while others bolster arguments for feeding strategies such as a pack hunting or cannibalism.
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Edité le 27/01/2008 à 12:55 par Nekarius
Posté par Nekarius
References
BENTON, M. J., 2005. Vertebrate Palaeontology (third edition). Blackwell Science Ltd. 456 pp.
BUFFETAUT, E. and SUTEETHORN, V., 1989. A sauropod skeleton associated with theropod teeth in the Upper Jurassic of Thailand: Remarks on the taphonomic and paleoecological significance of such associations. Palaeogeogr. Palaeoclimatol. Palaeoecol. 73, 77-83
BUFFETAUT, E., MARTILL D. & ESCUILLIE, F., 2004. Pterosaurs as part of a spinosaur diet. Nature, 430, 33.
CARPENTER, K., 2000. Evidence of predatory behavior by carnivorous dinosaurs. Gaia 15, 135-144.
CHARIG, A.J. & MILNER A.C., 1997. Baryonyx walkeri, a fish-eating dinosaur from the Wealden of Surrey. Bull. Hist. Mus. nat., 53, 11-70.
CHIN, K. 2007. The paleobiological implications of herbivorous dinosaur coprolites from the upper cretaceous Two Medicine formation of Montana: Why eat wood? Palaios 22(5), 554-566.
CHIN, K., 1997. What did dinosaur eat? Coprolites and other direct evidence of dinosaur diets. p. 371-382. In: The Complete Dinosaur.
FARLOW, J.O., AND BRETT-SURMAN, M.K. Indiana University Press: Bloomington and Indianapolis, 753 pp.
CHIN, K., EBERTH, D. A., SCHWEITZER, M. H., RANDO, T. A., SLOBODA, W. J. & HORNER, J. R., 2003. Remarkable preservation of undigested muscle tissue within a Late Cretaceous tyrannosaurid coprolite from Alberta, Canada. Palaios, 18, 287-293.
CHIN, K., TOKARYK, T.T., ERICKSON, G.M., and CALK, L.C., 1998. A king-sized theropod coprolite. Nature, 393, 680–682.
CURRIE, P.J. AND A. R. JACOBSEN. 1995. An azhdarchid pterosaur eaten by a velociraptorine theropod. Canadian Journal of Earth Sciences 32, 922-925.
FARLOW, J.O. & T.R. HOLTZ, JR. 2002. The fossil record of predation in dinosaurs. Pp. 251-266, in M. Kowalewski & P.H. Kelley (eds.), The Fossil Record of Predation. The Paleontological Society Papers 8.
HOLTZ, T.R., JR., BRINKMAN, D.L. AND CHANDLER, C.L., 1998. Denticle morphometrics and a possibly omnivorous feeding habit for the theropod dinosaur Troodon. Gaia, 15, 159-166.
JI, Q., CURRIE, P.J., NORELL, M.A., AND JI, S., 1998. Two feathered dinosaurs from northeastern China. Nature, 393 (6687), 753-761.
MARTIN, A. J., 2001. Introduction to the Study of Dinosaurs. Oxford: Blackwell Science. 426 pp.
NESBITT, S.J., TURNER, A.H., ERICKSON, G.M., AND NORELL, M.A., 2006. Prey choice and cannibalistic behaviour in the theropod Coelophysis. Biology Letters, First Cite Early Online Publishing.
NORMAN, D., 2003. Feeding Adaptations in the Dinosauria, p. 249–266. In G. S. Paul (ed.), The Scientific American Book of Dinosaurs. St. Martin's Press New York 432 pp.
PRASAD, V., STROMBERG, C.A.E., ALIMOHAMMADIAN, H., and SAHNI, A., 2005. Dinosaur coprolites and the early evolution of grasses and grazers. Science, 310, 177-180.
ROGERS, R. R., KRAUSE, D. W. & CURRY ROGERS, K., 2003. Cannibalism in the Madagascan dinosaur Majungatholus atopus. Nature, 422, 515-518.
SANZ, J.L., CHIAPPE L.M., FERNADEZ-JALVO Y., ORTEGA F., SANCHEZ-CHILLON B., POYATO-ARIZA F.J. & PÉREZ-MORENO B.P., 2001. An Early Cretaceous pellet. Nature 409, 998-999.
SUES, H.-D., FREY, E., MARTILL, D. M. & SCOTT, D. M., 2002. Irritator challengeri, a spinosaurid (Dinosauria: Theropoda) from the Lower Cretaceous of Brazil. J. Vert. Paleontol. 22 (3), 535-547.
THOMAS D. A. & FARLOW, J. O., 2003. Tracking dinosaur society, p. 232–241. In G. S. Paul (ed.), The Scientific American Book of Dinosaurs. St. Martin's Press, New York 432 pp.
TIFFNEY, B.H., 1997. Land plants as food and habitat in the age of dinosaurs. pp. 352-370. IN Farlow, J.H. and M.K. Brett-Surman (eds.), The Complete Dinosaur. Indiana University Press: Bloomington and Indianapolis, 753 pp.
WEISHAMPEL, D.B., DODSON, P., & OSMOLSKA, H., 2004. The Dinosauria (2nd edition), Berkeley: University of California Press, 880 pp.
WINGS, O. & SANDER, P.M., 2007. No gastric mill in sauropod dinosaurs: new evidence from analysis of gastrolith mass and function in ostriches. Proc. R. Soc. B 274 (1610), 635–640.
WINGS, O., 2007. A review of gastrolith function with implications for fossil vertebrates and a revised classification. Acta Palaeontologica Polonica 52(1), 1-16.
BENTON, M. J., 2005. Vertebrate Palaeontology (third edition). Blackwell Science Ltd. 456 pp.
BUFFETAUT, E. and SUTEETHORN, V., 1989. A sauropod skeleton associated with theropod teeth in the Upper Jurassic of Thailand: Remarks on the taphonomic and paleoecological significance of such associations. Palaeogeogr. Palaeoclimatol. Palaeoecol. 73, 77-83
BUFFETAUT, E., MARTILL D. & ESCUILLIE, F., 2004. Pterosaurs as part of a spinosaur diet. Nature, 430, 33.
CARPENTER, K., 2000. Evidence of predatory behavior by carnivorous dinosaurs. Gaia 15, 135-144.
CHARIG, A.J. & MILNER A.C., 1997. Baryonyx walkeri, a fish-eating dinosaur from the Wealden of Surrey. Bull. Hist. Mus. nat., 53, 11-70.
CHIN, K. 2007. The paleobiological implications of herbivorous dinosaur coprolites from the upper cretaceous Two Medicine formation of Montana: Why eat wood? Palaios 22(5), 554-566.
CHIN, K., 1997. What did dinosaur eat? Coprolites and other direct evidence of dinosaur diets. p. 371-382. In: The Complete Dinosaur.
FARLOW, J.O., AND BRETT-SURMAN, M.K. Indiana University Press: Bloomington and Indianapolis, 753 pp.
CHIN, K., EBERTH, D. A., SCHWEITZER, M. H., RANDO, T. A., SLOBODA, W. J. & HORNER, J. R., 2003. Remarkable preservation of undigested muscle tissue within a Late Cretaceous tyrannosaurid coprolite from Alberta, Canada. Palaios, 18, 287-293.
CHIN, K., TOKARYK, T.T., ERICKSON, G.M., and CALK, L.C., 1998. A king-sized theropod coprolite. Nature, 393, 680–682.
CURRIE, P.J. AND A. R. JACOBSEN. 1995. An azhdarchid pterosaur eaten by a velociraptorine theropod. Canadian Journal of Earth Sciences 32, 922-925.
FARLOW, J.O. & T.R. HOLTZ, JR. 2002. The fossil record of predation in dinosaurs. Pp. 251-266, in M. Kowalewski & P.H. Kelley (eds.), The Fossil Record of Predation. The Paleontological Society Papers 8.
HOLTZ, T.R., JR., BRINKMAN, D.L. AND CHANDLER, C.L., 1998. Denticle morphometrics and a possibly omnivorous feeding habit for the theropod dinosaur Troodon. Gaia, 15, 159-166.
JI, Q., CURRIE, P.J., NORELL, M.A., AND JI, S., 1998. Two feathered dinosaurs from northeastern China. Nature, 393 (6687), 753-761.
MARTIN, A. J., 2001. Introduction to the Study of Dinosaurs. Oxford: Blackwell Science. 426 pp.
NESBITT, S.J., TURNER, A.H., ERICKSON, G.M., AND NORELL, M.A., 2006. Prey choice and cannibalistic behaviour in the theropod Coelophysis. Biology Letters, First Cite Early Online Publishing.
NORMAN, D., 2003. Feeding Adaptations in the Dinosauria, p. 249–266. In G. S. Paul (ed.), The Scientific American Book of Dinosaurs. St. Martin's Press New York 432 pp.
PRASAD, V., STROMBERG, C.A.E., ALIMOHAMMADIAN, H., and SAHNI, A., 2005. Dinosaur coprolites and the early evolution of grasses and grazers. Science, 310, 177-180.
ROGERS, R. R., KRAUSE, D. W. & CURRY ROGERS, K., 2003. Cannibalism in the Madagascan dinosaur Majungatholus atopus. Nature, 422, 515-518.
SANZ, J.L., CHIAPPE L.M., FERNADEZ-JALVO Y., ORTEGA F., SANCHEZ-CHILLON B., POYATO-ARIZA F.J. & PÉREZ-MORENO B.P., 2001. An Early Cretaceous pellet. Nature 409, 998-999.
SUES, H.-D., FREY, E., MARTILL, D. M. & SCOTT, D. M., 2002. Irritator challengeri, a spinosaurid (Dinosauria: Theropoda) from the Lower Cretaceous of Brazil. J. Vert. Paleontol. 22 (3), 535-547.
THOMAS D. A. & FARLOW, J. O., 2003. Tracking dinosaur society, p. 232–241. In G. S. Paul (ed.), The Scientific American Book of Dinosaurs. St. Martin's Press, New York 432 pp.
TIFFNEY, B.H., 1997. Land plants as food and habitat in the age of dinosaurs. pp. 352-370. IN Farlow, J.H. and M.K. Brett-Surman (eds.), The Complete Dinosaur. Indiana University Press: Bloomington and Indianapolis, 753 pp.
WEISHAMPEL, D.B., DODSON, P., & OSMOLSKA, H., 2004. The Dinosauria (2nd edition), Berkeley: University of California Press, 880 pp.
WINGS, O. & SANDER, P.M., 2007. No gastric mill in sauropod dinosaurs: new evidence from analysis of gastrolith mass and function in ostriches. Proc. R. Soc. B 274 (1610), 635–640.
WINGS, O., 2007. A review of gastrolith function with implications for fossil vertebrates and a revised classification. Acta Palaeontologica Polonica 52(1), 1-16.
Posté par Nekarius
Pictures of indirect evidence
Fig. I: General tooth shapes typically with certain clades of dinosaurs. (A) Leaf-like tooth (Atirhinus kurzanvi). (B) Peg-like tooth (Diplodocus longus). (C) Spatulate tooth (Patagosaurus fariasi). (D) Bladed tooth (Tarbosaurus baatar). (E) Conical tooth (Irritator challengeri, Sues et al. 2002). (Weishampel et al. 2004)
Fig. II: Skull of dinosaurs which possess a beak. (A) Agilisaurus louderbacki (Ornithopoda). (B) Bagaceratops rozhdestvenskyi (Marginocephalia). (C) Gallimimus bullatus (Ornithomimosauria). Scale = 2 cm (A), 5 cm (B, C) (Weishampel et al. 2004).
A
B
Fig. III: Lower jaw of Kritosaurus seen at an angle to show the dental batteries and left jaw of a Hadrosaurus showing the tooth battery (Benton 2005).
Fig. IV: Comparison between a large and robust skull from a super-predator (Allosaurus fragilis, Weishampel et al. 2004) and a slender and narrow skull from a piscivorous carnivore (Suchomimus tenerensis, Sereno et al. 1998).
Fig. V: A. Left foot of the dromaeosaurid Deinonychus antirrhopus, showing the scythe claw on digit II. B. Large ungual phalanx of the spinosaurid Baryonyx walkeri handed by its discoverer William Walker.
A
B
Fig. VI: A. Cluster of gastroliths in the ceratopsian dinosaur Psittacosaurus from the Lower Cretaceous of Mongolia (Wings 2007). B. Cluster of gastroliths in the oviraptosaur dinosaur Caudiperyx from the Lower Cretaceous of China (Ji et al. 1998)
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Edité le 27/01/2008 à 12:57 par Nekarius
Fig. I: General tooth shapes typically with certain clades of dinosaurs. (A) Leaf-like tooth (Atirhinus kurzanvi). (B) Peg-like tooth (Diplodocus longus). (C) Spatulate tooth (Patagosaurus fariasi). (D) Bladed tooth (Tarbosaurus baatar). (E) Conical tooth (Irritator challengeri, Sues et al. 2002). (Weishampel et al. 2004)
Fig. II: Skull of dinosaurs which possess a beak. (A) Agilisaurus louderbacki (Ornithopoda). (B) Bagaceratops rozhdestvenskyi (Marginocephalia). (C) Gallimimus bullatus (Ornithomimosauria). Scale = 2 cm (A), 5 cm (B, C) (Weishampel et al. 2004).
A
B
Fig. III: Lower jaw of Kritosaurus seen at an angle to show the dental batteries and left jaw of a Hadrosaurus showing the tooth battery (Benton 2005).
Fig. IV: Comparison between a large and robust skull from a super-predator (Allosaurus fragilis, Weishampel et al. 2004) and a slender and narrow skull from a piscivorous carnivore (Suchomimus tenerensis, Sereno et al. 1998).
Fig. V: A. Left foot of the dromaeosaurid Deinonychus antirrhopus, showing the scythe claw on digit II. B. Large ungual phalanx of the spinosaurid Baryonyx walkeri handed by its discoverer William Walker.
A
B
Fig. VI: A. Cluster of gastroliths in the ceratopsian dinosaur Psittacosaurus from the Lower Cretaceous of Mongolia (Wings 2007). B. Cluster of gastroliths in the oviraptosaur dinosaur Caudiperyx from the Lower Cretaceous of China (Ji et al. 1998)
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Edité le 27/01/2008 à 12:57 par Nekarius
Posté par Nekarius
Mince, j'avais oublié que les fenêtres de s'adaptaient plus aux images.
C'est pas plus mal mais j'ignore comment je dois redimensioner les images qui viennent d'être postées...
Si on pouvait me permettre de rééditer mon post, ce serait sympa.
Tant pis je continue...
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Edité le 23/08/2008 à 12:29 par Nekarius
C'est pas plus mal mais j'ignore comment je dois redimensioner les images qui viennent d'être postées...
Si on pouvait me permettre de rééditer mon post, ce serait sympa.
Tant pis je continue...
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Edité le 23/08/2008 à 12:29 par Nekarius
Posté par Nekarius
Pictures of direct evidence
Fig. VII: Fossil imprints of the Paluxy River trackway and reconstructed attack sequence suggesting that the theropod approached in step with its prey (Thomas & Farlow 2003).
A
B
Fig. VIII: A. Fighting scene with Velociraptor and Protoceratops (American Museum of Natural History). B. Pterosaur vertebra perforated by a spinosaur tooth. Scale bar: 10 mm. (Buffetaut et al. 2004).
A
B
Fig. IX: A. Detailed of the traumatized tail section of Edmontosaurus annectens showing the puncture marks on the neural spines (Carpenter 1998). B. Chevrons of Majungatholus atopus with set of parallel tooth marks (arrows). Scale bar, 1 cm (Rogers et al. 2003).
A
B
Fig. X: A. Abdominal region of Coelophysis showing intact stomach (dotted line) with preserved contents highlighted in yellow (Nesbitt et al. 2006). B. Illustration from Nopsca showing the gastric content of the German Compsognathus specimen.
Fig. XI: Fossil pellet from the Lower Cretaceous of Las Hoyas (Spain). (Sanz et al. 2001).
A
B
Fig. XII: A. Large, bone-bearing tyrannosaurid coprolite with some of the broken pieces that had eroded downslope. Scale = 10 cm (Chin et al. 1998). B. Maiasaura coprolite from the Two Medicine Formation. Scale = 10 cm (Chin 2007).
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Edité le 27/01/2008 à 12:59 par Nekarius
Fig. VII: Fossil imprints of the Paluxy River trackway and reconstructed attack sequence suggesting that the theropod approached in step with its prey (Thomas & Farlow 2003).
A
B
Fig. VIII: A. Fighting scene with Velociraptor and Protoceratops (American Museum of Natural History). B. Pterosaur vertebra perforated by a spinosaur tooth. Scale bar: 10 mm. (Buffetaut et al. 2004).
A
B
Fig. IX: A. Detailed of the traumatized tail section of Edmontosaurus annectens showing the puncture marks on the neural spines (Carpenter 1998). B. Chevrons of Majungatholus atopus with set of parallel tooth marks (arrows). Scale bar, 1 cm (Rogers et al. 2003).
A
B
Fig. X: A. Abdominal region of Coelophysis showing intact stomach (dotted line) with preserved contents highlighted in yellow (Nesbitt et al. 2006). B. Illustration from Nopsca showing the gastric content of the German Compsognathus specimen.
Fig. XI: Fossil pellet from the Lower Cretaceous of Las Hoyas (Spain). (Sanz et al. 2001).
A
B
Fig. XII: A. Large, bone-bearing tyrannosaurid coprolite with some of the broken pieces that had eroded downslope. Scale = 10 cm (Chin et al. 1998). B. Maiasaura coprolite from the Two Medicine Formation. Scale = 10 cm (Chin 2007).
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Edité le 27/01/2008 à 12:59 par Nekarius
Posté par Webmaster
Bravo pour ce travail!
Tu peux maintenant éditer tes posts dans ce forum si tu veux.
La taille maximale visible des images est de 550 pixels.
Posté par Dinomaster
ça t'interesse d'être publié egalement sur mon nouveau site en gestation, ya une partie sur l'alimentation des dinosaures.
Posté par Nekarius
Pour sûr que ca m'intéresse...
Et je dois faire quoi pour ca ?
Si c'est un simple copier-coller, y'a pas de problème...
Et je dois faire quoi pour ca ?
Si c'est un simple copier-coller, y'a pas de problème...
Posté par Dinomaster
Je pense que mon nouveau site ne sera pas en ligne avant deux mois.
Tu n'as rien à faire sauf me donner une version français de ton article si tu as le temps ...
Sur le site il figurera tel quel, avec une mise en page conforme à ma charte graphique bien sur
Mais globalement je cherche des articles originaux sur les dinosaures (alimentation, reproduction, origine, disparition etc etc). J'ai écrit quelques articles sur mon site actuel, mais cela me prend du temps et ça reste loin d'articles professionnels comme le tient.
Tu n'as rien à faire sauf me donner une version français de ton article si tu as le temps ...
Sur le site il figurera tel quel, avec une mise en page conforme à ma charte graphique bien sur
Mais globalement je cherche des articles originaux sur les dinosaures (alimentation, reproduction, origine, disparition etc etc). J'ai écrit quelques articles sur mon site actuel, mais cela me prend du temps et ça reste loin d'articles professionnels comme le tient.
Posté par Nekarius
Salut Dinomaster,
Non, non, s'il te plait, cet "article" sur l'alimentation n'a rien de professionel, crois moi!!! C'est un simple travail que je devais rendre pour un cours et aussi un simple compte rendu de nos connaissances actuels sur l'alimentation des dinosaures en utilisant la bibliographie nécéssaire. Je te jure que c'est tout-à-fait comparable aux articles que tu as pu écrire.
Je ferai mon possible pour traduire rapidement le texte en français et te l'envoyer...
A très bientôt (sur Msn qui sait...?) et bonne après-midi,
Christophe
Non, non, s'il te plait, cet "article" sur l'alimentation n'a rien de professionel, crois moi!!! C'est un simple travail que je devais rendre pour un cours et aussi un simple compte rendu de nos connaissances actuels sur l'alimentation des dinosaures en utilisant la bibliographie nécéssaire. Je te jure que c'est tout-à-fait comparable aux articles que tu as pu écrire.
Je ferai mon possible pour traduire rapidement le texte en français et te l'envoyer...
A très bientôt (sur Msn qui sait...?) et bonne après-midi,
Christophe
Posté par Dinomaster
Merci à toi toute tes productions seront le bienvenu.
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