[D] Gargantuavis philoinos [~/~]
Describer
Buffetaut & Le Loeuff, 1998
Time
Cretaceous Late Maastrichtian
Classification
Saurischia Theropoda Tetanurae Coelurosauria Maniraptora Avialae Ornithothoraces Ornithurae
Fossilsite
Marnes Rouges inferieures, Languedoc region, Bellevue, Campagne-sur-Aude, Aude, Gres a Reptile Formation, Var, France
Info
Synsacrum and femur.
Buffetaut, E. & J. Le Loeuff. (1998). A new giant ground Bird from the Upper Cretaceous of southern France. J. geol. Soc. London, 155:1-4.
Abstract
New discoveries afford a much better knowledge of the large birds previously reported from the Upper Cretaceous of southern France on the basis of a single synsacrum fragment. An incomplete pelvis consisting of the synsacrum with part of the ilia is used to define a new taxon of bird, Gargantuavis philoinos, to which a femur is also referred. This bird is characterized by its very large size (comparable to that of an ostrich), a broad pelvis with an anteriorly placed acetabulum, and a short robust femur. The occurrence of this very large, flightless, bird in the Late Cretaceous shows that, contrary to widespread opinion, the evolution of large terrestrial birds was not simply the result of adaptation during the Cenozoic to ecological niches left empty by the extinction of the dinosaurs. It also strongly suggests that some of the large fossil eggs from the Upper Cretaceous of southern France were laid by large ground birds rather than dinosaurs.
Diagnosis
A very large bird with a broad pelvis, on which the acetabulum is placed in a very anterior position, at the level of the third and fourth synsacral transverse processes. The robust and relatively short synsacrum consists of ten completely fused vertebrae. The ilia do not meet each other dorsally. A welldeveloped antitrochanter is present posterodorsally to the relatively large acetabulum.
Etymology
Generic name from Gargantua, the giant of French folklore made famous by Francois Rabelais, and avis, Latin for bird. Specific name from the Greek philoinos, `one who likes wine\\\', because the sites which have yielded remains of this bird are in the midst of vineyards.
Holotype
Synsacrum with parts of the pelvis. Musee des Dinosaures, Esperaza, MDE-C3-525.
Referred specimen
Femur, Musee des Dinosaures, Esperaza, MDE-A08. This bone is referred to the same taxon as the pelvis because of agreement in size and compatible morphology (with, notably, a large trochanteric crest which probably matched a well developed antitrochanter on the ilium).
Type locality
The holotype synsacrum was found at the Bellevue site at Campagne-sur-Aude (departement Aude). The femur is from the Combebelle site (departement Herault). Both localities are in the Languedoc region of southern France.
Type stratum
The Bellevue site is at the base of the continental Marnes de la Maurine Formation; it has yielded a rich vertebrate fauna (Buffetaut et al. 1989; Le Loeuff 1995) dominated by titanosaurid sauropods and the ornithopod Rhabdodon. In southern France, this type of assemblage is characteristic of the late Campanian and early Maastrichtian, as opposed to late Maastrichtian assemblages in which hadrosaurs are dominant (Le Loeuff et al. 1994; Buffetaut et al. 1997). The Combebelle site has yielded a dinosaur assemblage, with Rhabdodon and a titanosaurid, indicating a similar age.
Description
The partial pelvis from Bellevue consists of the synsacrum and the attached ilia, which are somewhat distorted and incomplete. All the constituent vertebrae of the synsacrum are completely fused, as in other birds and much more so than in any described dinosaur. Because of this fusion, the exact number of vertebrae in the synsacrum is not easy to determine.
On the basis of the transverse processes which meet the ilia, it appears that ten vertebrae are present, a number similar to that observed in some Cretaceous birds such as Baptornis and Ichthyornis, and higher than that of any known theropod dinosaur (Chiappe, 1996). The centra are 30 mm wide at the broadest (anterior) part of the synsacrum, which makes it as broad as that of an adult ostrich, but its preserved length (probably close to the original length) is only 180 mm. The ventral surface of the synsacrum is markedly arched longitudinally.
Anteriorly, it bears a median ridge, which is replaced by a median groove at the level of the acetabulum. The concave anterior articular face of the first synsacral vertebra is subcircular, rather than saddle-shaped as in most birds. The opening of the neural canal is relatively small and circular in outline. Dorsally, the fused neurapophyses of the synsacral vertebrae form a continuous low ridge. The transverse processes connecting the synsacrum with the ilia are robust. In the anterior part, they are deep, perpendicular to the axis of the synsacrum and consist of a dorsal and a ventral bar, whereas the more posterior ones are simple, thinner and oblique.
The incomplete and crushed ilia show few details. The most striking feature is the very anterior position of the acetabulum, which is at the level of the third and fourth transverse processes. The acetabulum is about 40 mm in diameter and ventrolaterally oriented. On the left side, a large antitrochanter is preserved, again an avian feature (Chiappe, 1996). The dorsal iliac crest is preserved on the right side and it is clear that the ilia did not meet medially above the synsacrum. A small part of the anterior end of the ilio-ischiatic fenestra is visible on the left side. This pelvis is characterized mainly by its great relative breadth (150 mm at the level of the acetabulum), by the anterior position of the acetabulum, and by the failure of the ilia to meet dorsally. It is different in its robustness from that of flying birds and is also very much unlike the relatively narrow pelves of modern ratites, and the very narrow ones of phorusrhacids.
In this respect, as in the anterior position of the acetabulum, it is somewhat reminiscent of the Early Tertiary Diatryma (Matthew & Granger, 1917; Andors, 1992), but there are differences in the dorsal extent of the ilia and in the shape of the anterior articular surface of the synsacrum. This broad and heavily built pelvis is interpreted as that of a large, probably not fast-running, flightless bird. The previously reported synsacrum fragment from Provence (Buffetaut et al. 1995) is similar to the middle part of the Bellevue specimen.
The femur from Combebelle referred to Gargantuavis philoinos is not very well preserved, being crushed and damaged by modern bush roots. The distal end is missing, although the distal widening of the shaft suggests that not much is lacking, but the proximal end is tolerably well preserved. It is a short stout bone, with a hollow but thickwalled shaft (thickness of the bony walls up to 8 mm). The articular head is well defined, rounded, with a diameter of 40 mm (which fits that of the acetabulum of the pelvis from Bellevue).
A well marked \\\'neck\\\' separates the articular head from the more lateral region, in which there is a trochanteric crest similar to that of most birds, with no indication of the posterior trochanter present in dromaeosaurids, Archaeopteryx and enantiornithines (Chiappe, 1996). This crest is rounded in outline, instead of proximally pointed as in most large flightless birds. The great development of the crest matches that of the antitrochanter on the pelvis from Bellevue, thus supporting an attribution to the same taxon.
In proximal view, the proximal articular surface is similar in outline to that of ratites and Diatryma. The minimum circumference of the shaft is 148 mm, in the size range of the living ostrich. Equations devised to estimate the weight of vertebrates on the basis of the circumference of the femoral shaft (Anderson et al. 1985) can be applied to the Combebelle specimen. The resulting estimated weight is 141 kg, which places it within the weight range of ostriches. This is further evidence of the flightless nature of this bird, the estimated weight for the largest known flying bird, Argentavis magnificens, being only 71.9 kg (Campbell & Marcus, 1992).
Comparisons
The combination of characters seen on the pelvis of Gargantuavis philoinos separates it from all previously described birds and justifies the erection of a new taxon. The number of synsacral vertebrae. although not very large by comparison with modern birds, which have 11 to 23 synsacral vertebrae. is slightly larger than in Patagopteryx and in known enantiornithines (Chiappe, 1996). Among known Cretaceous birds. the great relative breadth of the pelvis is found only in Patagopteryx (Bonaparte & Alvarenga, 1992: Chiappe, 1996) and among later birds it is reminiscent mainly of robust extinct ground birds such as Diatryma (Matthew & Granger, 1917: Andors, 1992), but in the latter. as in most modern birds. the ilia meet dorsally above the neural spines of the synsacral vertebrae. unlike the condition in Gargantuavis and Patagopteryx. The very anterior position of the acetabulum is remarkable; again. the condition in Gargantuaris is rather similar to that in Patagopteryx, and approximated, but not to the same extent. by Diatryma.
The systematic position of Gargantuavis is debatable, although the number of synsacral vertebrae clearly places it in the unnamed group of Ornithothoraces comprising the Enantiornithes. Patagopteryx and the Ornithurae (Chiappe, 1996). The absence of a posterior trochanter on the femur suggests that it is more derived than the enantiornithines, but the relatively large size of the acetabulum (Chiappe, 1996) may suggest that it is not an ornithurine.
As mentioned above. it resembles the smaller, chicken-sized Patagoperyx diferrariisi (Bonaparte & Alvarenga, 1992: Chiappe, 1996). from the Upper Cretaceous of Patagonia. in several respects. but it is much larger and more robust. with a larger number of synsacral vertebrae. Whether the resemblances indicate really close relationships between Gargantuavis and Patagopteryx, which is more derived than the enantiornithines but less so than the ornithurines (Chiappe, 1995, 1996). is uncertain, but possible.
Conclusions
Giant birds and dinosaurs. Gargantuavis philoinos is not the first flightless bird to be reported from the Cretaceous. Both Patagopteryx (Bonaparte & Alvarenga, 1992; Chiappe, 1996) and Hesperornis (Marsh, 1880) (and related marine birds), from the Upper Cretaceous of North America, were also flightless. However, the adaptations of Gargantuavis were different from those of the diving Hesperornithiformes, with their narrow pelvis, and it was much larger than either Hesperornis regalis or Patagopteryx.
Gargantuavis is so far the oldest known flightless bird to have reached a very large size (approximately that of an ostrich, although its proportions were probably different). According to a widely held view (Romer, 1966; Kurten, 1971; Beaumont, 1974; Benton, 1990), large flightless birds (such as the Gastornithidae and the Phorusrhacidae) evolved in the early Tertiary to fill terrestrial ecological niches left vacant by the extinction of the dinosaurs at the end of the Cretaceous.
The occurrence of Gargantuavis together with dinosaurs in the Late Cretaceous of Europe shows that the extinction of the dinosaurs was in fact not a prerequisite for the evolution of large ground birds. The occurrence of giant ground birds in western Europe during the Late Cretaceous may be linked to the absence there of ostrich-like ornithomimid dinosaurs, which were widespread during the same time interval both in Asia and in North America, and may have occupied a similar ecological niche.
However, we need more giant bird material from Europe in order to assess the extent of convergent adaptation between those birds and ornithomimids. Whether there are any direct phylogenetic links between Gargantuavis and later large flightless birds seems unlikely in view of the above-mentioned peculiarities of the former, and the resemblances with Diatryma are probably explainable as convergences linked to similar adaptations in large and heavily built flightless birds.
The discovery of Gargantuavis has a bearing on the interpretation of the large fossil eggs found in great abundance in the Upper Cretaceous of France. This large flightless bird must have laid large eggs on the ground. It is therefore likely that some of the above-mentioned eggs actually were laid by Gargantuavis rather than by dinosaurs, as is usually assumed-all the more so that eggshell fragments with a bird-like microstructure have been reported from the Upper Cretaceous of southern France (Cousin, 1997). We therefore urge caution when discussing the chronology of dinosaur extinction in western Europe on the basis of eggshell remains alone.
We are grateful to the Association Culturelle et Archeologique Cruziate for providing us with the femur from Combebelle. and to the many volunteers who took part in the excavations at Bellevue, as well as to the owners of the site. We thank E. Gaffney (American Museum of Natural History, New York), A. Milner (The Natural History Museum, London) and C. Lefevre (Museum National d\\\'Histoire Naturelle, Paris) for access to specimens in their care. A. Andors (New York), L. Chiappe (New York) and L. Martin (Lawrence) offered valuable advice. This work was supported by the Institut National des Sciences de l\\\'Univers (Paris) and the Musee des Dinosaures (Esperaza).
Buffetaut & Le Loeuff, 1998
Time
Cretaceous Late Maastrichtian
Classification
Saurischia Theropoda Tetanurae Coelurosauria Maniraptora Avialae Ornithothoraces Ornithurae
Fossilsite
Marnes Rouges inferieures, Languedoc region, Bellevue, Campagne-sur-Aude, Aude, Gres a Reptile Formation, Var, France
Info
Synsacrum and femur.
Buffetaut, E. & J. Le Loeuff. (1998). A new giant ground Bird from the Upper Cretaceous of southern France. J. geol. Soc. London, 155:1-4.
Abstract
New discoveries afford a much better knowledge of the large birds previously reported from the Upper Cretaceous of southern France on the basis of a single synsacrum fragment. An incomplete pelvis consisting of the synsacrum with part of the ilia is used to define a new taxon of bird, Gargantuavis philoinos, to which a femur is also referred. This bird is characterized by its very large size (comparable to that of an ostrich), a broad pelvis with an anteriorly placed acetabulum, and a short robust femur. The occurrence of this very large, flightless, bird in the Late Cretaceous shows that, contrary to widespread opinion, the evolution of large terrestrial birds was not simply the result of adaptation during the Cenozoic to ecological niches left empty by the extinction of the dinosaurs. It also strongly suggests that some of the large fossil eggs from the Upper Cretaceous of southern France were laid by large ground birds rather than dinosaurs.
Diagnosis
A very large bird with a broad pelvis, on which the acetabulum is placed in a very anterior position, at the level of the third and fourth synsacral transverse processes. The robust and relatively short synsacrum consists of ten completely fused vertebrae. The ilia do not meet each other dorsally. A welldeveloped antitrochanter is present posterodorsally to the relatively large acetabulum.
Etymology
Generic name from Gargantua, the giant of French folklore made famous by Francois Rabelais, and avis, Latin for bird. Specific name from the Greek philoinos, `one who likes wine\\\', because the sites which have yielded remains of this bird are in the midst of vineyards.
Holotype
Synsacrum with parts of the pelvis. Musee des Dinosaures, Esperaza, MDE-C3-525.
Referred specimen
Femur, Musee des Dinosaures, Esperaza, MDE-A08. This bone is referred to the same taxon as the pelvis because of agreement in size and compatible morphology (with, notably, a large trochanteric crest which probably matched a well developed antitrochanter on the ilium).
Type locality
The holotype synsacrum was found at the Bellevue site at Campagne-sur-Aude (departement Aude). The femur is from the Combebelle site (departement Herault). Both localities are in the Languedoc region of southern France.
Type stratum
The Bellevue site is at the base of the continental Marnes de la Maurine Formation; it has yielded a rich vertebrate fauna (Buffetaut et al. 1989; Le Loeuff 1995) dominated by titanosaurid sauropods and the ornithopod Rhabdodon. In southern France, this type of assemblage is characteristic of the late Campanian and early Maastrichtian, as opposed to late Maastrichtian assemblages in which hadrosaurs are dominant (Le Loeuff et al. 1994; Buffetaut et al. 1997). The Combebelle site has yielded a dinosaur assemblage, with Rhabdodon and a titanosaurid, indicating a similar age.
Description
The partial pelvis from Bellevue consists of the synsacrum and the attached ilia, which are somewhat distorted and incomplete. All the constituent vertebrae of the synsacrum are completely fused, as in other birds and much more so than in any described dinosaur. Because of this fusion, the exact number of vertebrae in the synsacrum is not easy to determine.
On the basis of the transverse processes which meet the ilia, it appears that ten vertebrae are present, a number similar to that observed in some Cretaceous birds such as Baptornis and Ichthyornis, and higher than that of any known theropod dinosaur (Chiappe, 1996). The centra are 30 mm wide at the broadest (anterior) part of the synsacrum, which makes it as broad as that of an adult ostrich, but its preserved length (probably close to the original length) is only 180 mm. The ventral surface of the synsacrum is markedly arched longitudinally.
Anteriorly, it bears a median ridge, which is replaced by a median groove at the level of the acetabulum. The concave anterior articular face of the first synsacral vertebra is subcircular, rather than saddle-shaped as in most birds. The opening of the neural canal is relatively small and circular in outline. Dorsally, the fused neurapophyses of the synsacral vertebrae form a continuous low ridge. The transverse processes connecting the synsacrum with the ilia are robust. In the anterior part, they are deep, perpendicular to the axis of the synsacrum and consist of a dorsal and a ventral bar, whereas the more posterior ones are simple, thinner and oblique.
The incomplete and crushed ilia show few details. The most striking feature is the very anterior position of the acetabulum, which is at the level of the third and fourth transverse processes. The acetabulum is about 40 mm in diameter and ventrolaterally oriented. On the left side, a large antitrochanter is preserved, again an avian feature (Chiappe, 1996). The dorsal iliac crest is preserved on the right side and it is clear that the ilia did not meet medially above the synsacrum. A small part of the anterior end of the ilio-ischiatic fenestra is visible on the left side. This pelvis is characterized mainly by its great relative breadth (150 mm at the level of the acetabulum), by the anterior position of the acetabulum, and by the failure of the ilia to meet dorsally. It is different in its robustness from that of flying birds and is also very much unlike the relatively narrow pelves of modern ratites, and the very narrow ones of phorusrhacids.
In this respect, as in the anterior position of the acetabulum, it is somewhat reminiscent of the Early Tertiary Diatryma (Matthew & Granger, 1917; Andors, 1992), but there are differences in the dorsal extent of the ilia and in the shape of the anterior articular surface of the synsacrum. This broad and heavily built pelvis is interpreted as that of a large, probably not fast-running, flightless bird. The previously reported synsacrum fragment from Provence (Buffetaut et al. 1995) is similar to the middle part of the Bellevue specimen.
The femur from Combebelle referred to Gargantuavis philoinos is not very well preserved, being crushed and damaged by modern bush roots. The distal end is missing, although the distal widening of the shaft suggests that not much is lacking, but the proximal end is tolerably well preserved. It is a short stout bone, with a hollow but thickwalled shaft (thickness of the bony walls up to 8 mm). The articular head is well defined, rounded, with a diameter of 40 mm (which fits that of the acetabulum of the pelvis from Bellevue).
A well marked \\\'neck\\\' separates the articular head from the more lateral region, in which there is a trochanteric crest similar to that of most birds, with no indication of the posterior trochanter present in dromaeosaurids, Archaeopteryx and enantiornithines (Chiappe, 1996). This crest is rounded in outline, instead of proximally pointed as in most large flightless birds. The great development of the crest matches that of the antitrochanter on the pelvis from Bellevue, thus supporting an attribution to the same taxon.
In proximal view, the proximal articular surface is similar in outline to that of ratites and Diatryma. The minimum circumference of the shaft is 148 mm, in the size range of the living ostrich. Equations devised to estimate the weight of vertebrates on the basis of the circumference of the femoral shaft (Anderson et al. 1985) can be applied to the Combebelle specimen. The resulting estimated weight is 141 kg, which places it within the weight range of ostriches. This is further evidence of the flightless nature of this bird, the estimated weight for the largest known flying bird, Argentavis magnificens, being only 71.9 kg (Campbell & Marcus, 1992).
Comparisons
The combination of characters seen on the pelvis of Gargantuavis philoinos separates it from all previously described birds and justifies the erection of a new taxon. The number of synsacral vertebrae. although not very large by comparison with modern birds, which have 11 to 23 synsacral vertebrae. is slightly larger than in Patagopteryx and in known enantiornithines (Chiappe, 1996). Among known Cretaceous birds. the great relative breadth of the pelvis is found only in Patagopteryx (Bonaparte & Alvarenga, 1992: Chiappe, 1996) and among later birds it is reminiscent mainly of robust extinct ground birds such as Diatryma (Matthew & Granger, 1917: Andors, 1992), but in the latter. as in most modern birds. the ilia meet dorsally above the neural spines of the synsacral vertebrae. unlike the condition in Gargantuavis and Patagopteryx. The very anterior position of the acetabulum is remarkable; again. the condition in Gargantuaris is rather similar to that in Patagopteryx, and approximated, but not to the same extent. by Diatryma.
The systematic position of Gargantuavis is debatable, although the number of synsacral vertebrae clearly places it in the unnamed group of Ornithothoraces comprising the Enantiornithes. Patagopteryx and the Ornithurae (Chiappe, 1996). The absence of a posterior trochanter on the femur suggests that it is more derived than the enantiornithines, but the relatively large size of the acetabulum (Chiappe, 1996) may suggest that it is not an ornithurine.
As mentioned above. it resembles the smaller, chicken-sized Patagoperyx diferrariisi (Bonaparte & Alvarenga, 1992: Chiappe, 1996). from the Upper Cretaceous of Patagonia. in several respects. but it is much larger and more robust. with a larger number of synsacral vertebrae. Whether the resemblances indicate really close relationships between Gargantuavis and Patagopteryx, which is more derived than the enantiornithines but less so than the ornithurines (Chiappe, 1995, 1996). is uncertain, but possible.
Conclusions
Giant birds and dinosaurs. Gargantuavis philoinos is not the first flightless bird to be reported from the Cretaceous. Both Patagopteryx (Bonaparte & Alvarenga, 1992; Chiappe, 1996) and Hesperornis (Marsh, 1880) (and related marine birds), from the Upper Cretaceous of North America, were also flightless. However, the adaptations of Gargantuavis were different from those of the diving Hesperornithiformes, with their narrow pelvis, and it was much larger than either Hesperornis regalis or Patagopteryx.
Gargantuavis is so far the oldest known flightless bird to have reached a very large size (approximately that of an ostrich, although its proportions were probably different). According to a widely held view (Romer, 1966; Kurten, 1971; Beaumont, 1974; Benton, 1990), large flightless birds (such as the Gastornithidae and the Phorusrhacidae) evolved in the early Tertiary to fill terrestrial ecological niches left vacant by the extinction of the dinosaurs at the end of the Cretaceous.
The occurrence of Gargantuavis together with dinosaurs in the Late Cretaceous of Europe shows that the extinction of the dinosaurs was in fact not a prerequisite for the evolution of large ground birds. The occurrence of giant ground birds in western Europe during the Late Cretaceous may be linked to the absence there of ostrich-like ornithomimid dinosaurs, which were widespread during the same time interval both in Asia and in North America, and may have occupied a similar ecological niche.
However, we need more giant bird material from Europe in order to assess the extent of convergent adaptation between those birds and ornithomimids. Whether there are any direct phylogenetic links between Gargantuavis and later large flightless birds seems unlikely in view of the above-mentioned peculiarities of the former, and the resemblances with Diatryma are probably explainable as convergences linked to similar adaptations in large and heavily built flightless birds.
The discovery of Gargantuavis has a bearing on the interpretation of the large fossil eggs found in great abundance in the Upper Cretaceous of France. This large flightless bird must have laid large eggs on the ground. It is therefore likely that some of the above-mentioned eggs actually were laid by Gargantuavis rather than by dinosaurs, as is usually assumed-all the more so that eggshell fragments with a bird-like microstructure have been reported from the Upper Cretaceous of southern France (Cousin, 1997). We therefore urge caution when discussing the chronology of dinosaur extinction in western Europe on the basis of eggshell remains alone.
We are grateful to the Association Culturelle et Archeologique Cruziate for providing us with the femur from Combebelle. and to the many volunteers who took part in the excavations at Bellevue, as well as to the owners of the site. We thank E. Gaffney (American Museum of Natural History, New York), A. Milner (The Natural History Museum, London) and C. Lefevre (Museum National d\\\'Histoire Naturelle, Paris) for access to specimens in their care. A. Andors (New York), L. Chiappe (New York) and L. Martin (Lawrence) offered valuable advice. This work was supported by the Institut National des Sciences de l\\\'Univers (Paris) and the Musee des Dinosaures (Esperaza).