[D] Enaliornis barretti [~/~]
Describer
Seeley, 1876
Time
Cretaceous Early Albian
Classification
Saurischia Theropoda Tetanurae Coelurosauria Maniraptora Avialae Ornithothoraces Ornithurae [Hesperonithiformes]
Fossilsite
Cambridge Green-sand-Formation, Cambridgeshire, England
Info
Enaliornis barretti ~/~ (Seeley, 1876) [= Palaeocolymbus barretti ~/~ (Seeley, 1876)] > Enaliornis sedgwicki ~/~ (Seeley, 1876) [= Pelagornis sedgwicki ~/~ (Seeley, 1876)] > Enaliornis seeleyi ~/~ (Galton and Martin, 2002)
Braincases, vertebrae, pelvis, limb elements.
Galton, P.M. & Martin, L.D. (2002) Postcranial anatomy and systematics of Enaliornis Seeley, 1876, a foot-propelled diving bird (Aves: Ornithurae: Hesperornithiformes) from the Early Cretaceous of England. Revue Paléobiol., Genève 21 (2): 489-538
Abstract
The vertebrae, pelvic girdle and hind limb bones from the Cambridge Greensand (upper Lower Cretaceous, Albian, Stoliczkaia dispar zone, ~100 mya) near Cambridge, southern England, show that the ornithuran foot-propelled diving bird Enaliornis is a basal hesperornithiform, not a primitive loon.
The “proximal ends of ulnae” are reidentified as proximal tarsometatarsi from adult individuals. The shapes of the distal tarsometatarsal trochlea indicate that the feet were lobbed, as in all hesperornithiformes and grebes, rather than webbed as in loons. The femur was laterally directed, but some sort of waddling gait was possible. Three species are recognized, based on three size groups (large as Enaliornis barretti, medium E. seeleyi n. sp., small E. sedgwicki), the form of the distal end of the tibiotarsus of adult individuals, and differences in the other bones.
Adult distal femora of each species show a probable sexual dimorphism in the sulcus patellaris, which is either shallow or deep. Juvenile individuals are well represented and, given the poor development of the articular surfaces, the nesting sites were probably quite close; two bones show numerous gnaw marks from the incisors of a small, presumably terrestrial mammal. The last cervical and the last thoracic vertebrae of Enaliornis are both heterocoelous, as in the other hesperornithiforms, so the incorrectly referred amphicoelous thoracic vertebrae represent a non-hesperornithiform bird, Aves incertae sedis.
Alonso, P.D., Milner, A.C., Ketcham, R.A., Cookson, M.J. & Rowe, T.B. (2004) . The avian nature of the brain and inner ear of Archaeopteryx. Nature Vol 430 666-669
The relatively small hemispheres, lack of posterior rotation of the optic lobes and potentially relatively smaller cerebellum suggest that Archaeopteryx and Enaliornis were more primitive than any modern bird.
Seeley, 1876
Time
Cretaceous Early Albian
Classification
Saurischia Theropoda Tetanurae Coelurosauria Maniraptora Avialae Ornithothoraces Ornithurae [Hesperonithiformes]
Fossilsite
Cambridge Green-sand-Formation, Cambridgeshire, England
Info
Enaliornis barretti ~/~ (Seeley, 1876) [= Palaeocolymbus barretti ~/~ (Seeley, 1876)] > Enaliornis sedgwicki ~/~ (Seeley, 1876) [= Pelagornis sedgwicki ~/~ (Seeley, 1876)] > Enaliornis seeleyi ~/~ (Galton and Martin, 2002)
Braincases, vertebrae, pelvis, limb elements.
Galton, P.M. & Martin, L.D. (2002) Postcranial anatomy and systematics of Enaliornis Seeley, 1876, a foot-propelled diving bird (Aves: Ornithurae: Hesperornithiformes) from the Early Cretaceous of England. Revue Paléobiol., Genève 21 (2): 489-538
Abstract
The vertebrae, pelvic girdle and hind limb bones from the Cambridge Greensand (upper Lower Cretaceous, Albian, Stoliczkaia dispar zone, ~100 mya) near Cambridge, southern England, show that the ornithuran foot-propelled diving bird Enaliornis is a basal hesperornithiform, not a primitive loon.
The “proximal ends of ulnae” are reidentified as proximal tarsometatarsi from adult individuals. The shapes of the distal tarsometatarsal trochlea indicate that the feet were lobbed, as in all hesperornithiformes and grebes, rather than webbed as in loons. The femur was laterally directed, but some sort of waddling gait was possible. Three species are recognized, based on three size groups (large as Enaliornis barretti, medium E. seeleyi n. sp., small E. sedgwicki), the form of the distal end of the tibiotarsus of adult individuals, and differences in the other bones.
Adult distal femora of each species show a probable sexual dimorphism in the sulcus patellaris, which is either shallow or deep. Juvenile individuals are well represented and, given the poor development of the articular surfaces, the nesting sites were probably quite close; two bones show numerous gnaw marks from the incisors of a small, presumably terrestrial mammal. The last cervical and the last thoracic vertebrae of Enaliornis are both heterocoelous, as in the other hesperornithiforms, so the incorrectly referred amphicoelous thoracic vertebrae represent a non-hesperornithiform bird, Aves incertae sedis.
Alonso, P.D., Milner, A.C., Ketcham, R.A., Cookson, M.J. & Rowe, T.B. (2004) . The avian nature of the brain and inner ear of Archaeopteryx. Nature Vol 430 666-669
The relatively small hemispheres, lack of posterior rotation of the optic lobes and potentially relatively smaller cerebellum suggest that Archaeopteryx and Enaliornis were more primitive than any modern bird.