The vertebral column is represented by little more than a mold of the form of the vertebræ, so that little can be said of its character. The individual vertebræ are short and hour-glass-shaped. The ribs are borne intercentrally, as in all the microsaurians which have been studied from the Linton deposits. The ribs are rather long and somewhat heavy, slightly curved and expanded at the proximal end, as though an incipient bicipital condition were present.
The right clavicle, which is preserved as an impression, is entire. Its impression shows this element to have been ornamented on its ventral surface with radiating grooves and ridges which started at the lower angle of the bone. The element is distinctly triangular, which is characteristic of the genus Tuditanus, so far as known. The fragment of the left clavicle adds nothing to our knowledge of the element.
The left humerus recalls in a striking way that of Tuditanus longipes Cope, and it was once entertained as a possibility that the present form might be a member of that species, since the skull is lacking in T. longipes. Sufficient specific differences were found, however, in the ribs, which, in T. longipes, are very long, slightly curved, and delicate, but which, in the present form, are comparatively heavy. Other characters sufficiently diagnostic are found in the form assumed by the vertebræ in the two forms.
| Measurements of the Type of Tuditanus walcotti Moodie. | |
| mm. | |
| Length of specimen | 70 |
| Length of skull | 20 |
| Posterior width of skull | 14 |
| Width of skull, anterior to orbits | 10 |
| Length of orbit | 4 |
| Width of orbit | 2 |
| Interorbital width | 3 |
| Length of clavicle | 9 |
| Greatest width of clavicle | 4 |
| Length of vertebral column, as preserved | 50 |
| Length of a vertebra | 1.75 |
| Width of a vertebra | 50 |
| Width of body impression | 15 |
| Length of humerus | 6 |
| Median width of humerus | 50 |
| Width at end of humerus | 2 |
| Length of rib | 8 |
| Width of rib | 25 |
The above-described specimen was collected by Mr. R. D. Lacoe, of Pittston, Pennsylvania, from Linton, Ohio.
A second individual (No. 4481, U. S. National Museum) of this species is indicated by a rather poorly preserved specimen on a slab of soft coal from the Linton mines. The following portions of the animal have been detected and will be discussed: partial impression of the skull, with a fragment of a minute jaw, in which are minute teeth; right clavicle; part of the impression of the body; nearly entire left hind limb; impressions of about a dozen vertebræ, very indistinct.
The impression of the skull is distinct only in a favorable light, and even then the boundaries of the cranium are a little uncertain. For this reason no representation of the form will be attempted. The sculpturing on the parietals is, however, distinct enough to show relationship with the previously described specimen, and the form of the body impression, the absence of abdominal scutes, the shape of the clavicle and its sculpture, and the proportions of the hind limbs all agree with the characters which have been assigned to the genus Tuditanus. The fragment of the jaw is interesting as giving the first information as to the character of the mandible in the genus Tuditanus. It is very slender and of uniform width as far as preserved. The teeth are short, blunt cones, apparently pleurodont.
The clavicle is of the typical Tuditanus form, with the sculpturing lines radiating out from the angle. The impression of the body adds nothing to that already described for the type specimen. The nearly entire hind limb is of great interest as adding another example of the phalangeal formula. The foot is almost perfectly preserved, and the formula was probably 2-2-3-3-2. The endochondrium of the limb bones is not highly developed. About a dozen vertebræ are represented by molds in the soft coal, but nothing of their structure can be determined.
The sharp, reptile-like claws in which the toes end ([fig. 21 , B]) recall those of Eosauravus and of Tuditanus minimus Moodie. It is another link in the chain of the suggested relationship between the microsaurians and the early reptiles.
| Measurements of the Second Specimen of Tuditanus walcotti Moodie. | |
| mm. | |
| Length of entire body impression | 75 |
| Width across belly, maximum | 16 |
| Length of skull | ?17 |
| Posterior width of skull | ?14 |
| Length of fragment of jaw | 4 |
| Width of fragment of jaw | 1.5 |
| Length of tooth in jaw | .25 |
| Length of clavicle | 8 |
| Width of clavicle, maximum | 4 |
| Length of hind limb | 22 |
| Length of femur | 8 |
| Length of tibia (?) | 6 |
| Length of metatarsal | 2 |
| Length of first digit | 6 |