8 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I49 



pronounced internal ligamental prominence ; and, its internal condylar 

 edge is more flaring posteriorly than in Ciconia, causing the posterior 

 intercondylar sulcus to be displaced medially (as in Jabiru, Euxenura 

 and Dissoura). The fossil resembles Ciconia in having a relatively 

 deep and narrow condylar head. 



The massiveness of the fossil tibiotarsus is responsible for some 

 of its similarities with Jabiru mycteria. Both have a pronounced 

 internal ligamental prominence, a papilla-like external ligamental 

 process, an unnotched connection between the intercondylar tubercle 

 and external condyle and a flaring margin of the posterior internal 

 condyle. The intercondylar groove, although similar in shape in 

 Dissourodes and Jabiru, is relatively narrower in the former than 

 in any specimen of Jabiru examined. The fossil tibiotarsus has a 

 narrower posterior condylar head than Jabiru, and its external 

 ligamental process does not extend as far proximally. The distal 

 opening of the fossil's tendinal groove is oval, not round in shape, 

 and it is not connected by a ridge with the intercondylar tubercle, 

 as in Jabiru. Also, Jabiru lacks (or has only vaguely present) a 

 process on the supratendinal bridge below the distal opening of the 

 tendinal groove ; this process in Dissourodes milleri produces a notch 

 above the anterior internal condyle (visible from the internal side). 



As has been suggested above, the fossil tibiotarsus most closely 

 agrees with that of Dissoura episcopus. The shape of the distal end 

 (viewed end-on) is identical in the two, including the shape of the 

 flaring posterior internal condylar surface, the shape and width of 

 the intercondylar groove, and the relatively narrow posterior margin. 

 The external ligamental process is papilla-like and about equally 

 short in both. The distal opening of the tendinal groove is elliptical 

 in both, and the ridge between the intercondylar tubercle and the 

 external condyle lacks a notch. Although the fossil represents a 

 much larger species, the thickness of the distal shaft and size of the 

 trochlear head are comparable in the two forms. Other similarities 

 include the shape of the condylar margins, depth of the condyles, 

 configuration of the internal ligamental prominence and the angle 

 of the tendinal groove. There are two noteworthy differences between 

 Dissoura and the fossil. There is in Dissoura a ridge between the 

 distal tendinal groove opening and the intercondylar tubercle. This 

 ridge seems to separate the opening from the rest of the intercondylar 

 fossa. The fossil lacks this ridge and the opening is in direct contact 

 with the deepest part of the fossa. Also, tibiotarsi of the two forms 

 differ in the configuration of the intercondylar fossa. In Dissoura 



