Technically, the common African ostrich is known as Struthio camelus, and so the ostrichlike birds, as a group, have come to be spoken of as the "struthious types," or those with "struthious characters." Again, the group as a whole has been designated as the Ratitæ, which primarily has reference to the fact that the breastbone or sternum in any one of them lacks a keel, and so is "raftlike" as compared with a sternum possessing the character.[1]
With but one or two exceptions, all the rest of existing birds have a more or less well-developed median keel on their sterna, and as the Carinatæ they form the second great division of the class Aves. Carina is the Latin word meaning "a keel," hence the name for the group. To this keel are attached the pectoral muscles, which are so essential to the power of flight.
Linking together the ratite and carinate avian groups, we have an interesting subgroup of birds known as the tinamous.[2] In 1827 L'Herminier thought that the nearest kin of the tinamous among the carinate birds were the rails (Rallidæ). They are South American and Mexican types, and about fifty species of them are known, and systematists have consigned these to some nine or ten genera. All these forms have a general external resemblance to each other, and, as many observers have noted, to those birds we call "partridges." The largest tinamous are about the size of our "prairie chickens," and the smallest about the size of the least of our "quails." They are fine eating; fly pretty well, but are foolish and easily captured. Some of them have but three toes on either foot, others four, and all lay wonderfully handsome eggs. These latter may be of various shades of green, blue, pink, or orange, varying with the species, but in all they have highly burnished shells resembling porcelain or brilliantly polished metal. Little is as yet known of their habits.
Sharpe speaks of the tinamous as "struthious partridges," and Hudson claims that some of their "habits are thoroughly partridgelike,"[3] and if they lead in the direction of the gallinaceous
- ↑ It is probable that all the early ancestors of birds were flightless, and consequently all had keelless sterna, except such forms as Ichthyornis, and, no doubt, its predecessors were ratite birds, in the sense that they had non-carinate breastbones.
- ↑ These birds have deep keels to their sterna, but at the same time possess so many struthious characters in their organizations that they have been designated by Huxley as the Dromæognnthæ—the genus Dromæus containing the emeu—and emeus and tinamous have the structure of the palate much the same.
- ↑ Nowadays most scientists refer to the tinamous as the Crypturi, from the fact that their tails are concealed by the coverts (Gr. krupto, I conceal, and oura, the tail).
India, which are also of birds which were of this group. All of these, both existing and fossil, arc or were flightless birds, and the African ostrich, no doubt, the most specialized of any of them. According to Cope, there was a gigantic ostrichlike bird that lived in Texas and New Mexico during the Eocene time (Diatryma). It was double the size of an ordinary ostrich. The largest moa, Dinornis giganteus, was nearly ten feet high.
