Athena Review Image Archive ™
Lithornis skull and brain
Skull and brain of Lithornis (after Mayr 2009 and xxxx).
The Lithornithidae were palaeognathous birds capable of flight, with a wide distribution in North America and Western Europe in the Early to Middle Eocene period (ca. 55-40 mya). Palaeognathus birds, which are largely terrestial, are the most primitive clade or branch of modern birds (Leonard et al. 2005).
Fossils of Lithornis have been found from the Green
River and Willwood Formations of Wyoming, the London Clay in England,
the Fur Formation in Denmark, and the Messel site in Germany. They are
in the class Aves, the superorder Palaeognathae, and the family
Lithornidae. The genus Lithornis has six named species.
The Lithornis
skull shown in this figure was recovered by Mayr (2008, 2009) at the
Messel site in Germany, which bordered an ancient lake. This skull has
a length of 65.9 mm, and a long and narrow beak, which it is assumed
was used for probing along
shorelines and other bodies of water, much as does a present-day ibis
or heron.
The brain endocast shows relatively large olfactory lobes as well as a large cerebral hemisphere. The prominent olfactory lobes in Lithornis can be correlated with those of other early birds, as well as some smaller dinosaurs from the Late Cretaceous period such as Velociraptor, who were active hunters. Many present-day birds, while they have relatively large cerebral hemispheres, have reduced olfactory lobes and depend less on a sense of smell than on vision.
References:
Houde, P. & S.L.Olson 1981. Paleognathous carinate birds from the early Tertiary of North America. Science, 214: 1236-1237.
Leonard,
L., G.J. Dyke, and M. Van Tuinen 2005. A new specimen of the
fossil palaeognath Lithornis from the lower Eocene of Denmark. American Museum Novitates, 3491: 1-11
Mayr,
G., 2008. First substantial middle Eocene record of the Lithornithidae
(Aves): A postcranial skeleton from Messel (Germany). Annales de Paléontologie, 94: 29-37.
Mayr, G., 2009. Towards the complete bird – the skull of the middle Eocene Messel lithornithid (Aves, Lithornithidae). Bulletin de l’Institut royal des Sciences naturelles de Belgique, Sciences de la Terre, 79: 169-173, 2 figs, 1 table, Brussels,
.
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