M. JOLLIE, FALCONIFORMES(part IV) 1(201) The coracoid sulci are peculiar in their depth and narrowness. The dorsal margins of the sulci have distinct, anteriorly facing coracoid pads, correlated with the reduced posterior flange of the coracoid. In Henpetothenee there are large, separate, lateral processcs, while Mieraetun, Miluago, Polyborua, and some species of Faleo have these processes noved toward the midline; a single median dorsal spine is found typically in Faleo (fig. 166). These processes are produced by ossifications in the origins of the supraeo"aeoi-deus muscles. Sna1l lateral processes are indicated in Spiziapteryx along with a nedian one. The sternocoracoid processes jut upward, out, and forward and end bluntly. The sternocoracoid fossa is like that of the accipitrid. The costal margin has five to six distinct rib articulations separated by pneunatic fossae (fig, 767). The Fig. L67. Lateral views of sterna of A. Faleo merieanus, B. Henpetothenes eaehinnans. sternal plates are cupped anteriorly.for the viscera but atre flat posteriorly. The posterior margin is square; it may be complete, or have a pair of fenestrae or notches (fig. 168). B Fig. 168. Ventral views of posterior part of sterna of A. Ealco mesieanua, two specimens (a and b); B. Microhierat eaeruleseens. The keel is thin; it is usually deepest along its anterior pi1lar. In outline it is roughly triangular with the anterior margin jutting slightly or distinctly forward and showing only a *** Evol. Theory 3:1-141 (October, f977) Part IV recelved September 9, L975; May 27 , I9TT 1977, The Unlverslty of Chlcago 9 2(202) M. JOLLIE slight curve along the line of junction of the carina and lateral plates. It tapers to its terminus on the posterior margin. Henpetotheres and ui,eraatur show an uptilting of the anterior end of the keel like that of the accipitrid. The eupraeoraeoideus scar is regular in outline and extends fron one-half to three-fifths of the length of the sternum. Its ventral nargin is well separated fron that of the keel (thick pectoralis muscle). The outer tip of the coracoid is not braced by a ligament as in the other groups; therefore, at the point where the sternocoracoid fossa and the lateral line of the supraeo"aeoideue muscle intersect there is a distinctive, scarless, triangular area (fig. L67). The falconid sternum can be characterized as follows: anterior dorsal margin with a single rnedial dorsal process, or two lateral ones, inconpletely or slightly separated; coracoid sulci deep and narrow and extensively lapped; coracoid pads reduced to anteriorly facing contact lines I ventral margin of the sternocoracoid fossa lacking a ligament scar; a delinited triangular area between the sternocoracoid fossa and the sup?a- eonaeoideue scar. Subgroups cannot be characterized, Sumrnaryand Conclus ions The sternum, like the shoulder area, shows such irregular variations from group to group that one wonders whether adaptive or phyletic features are involved. Since the forn of the thorax and- the pectoral musculature rnolds the overall shape of this bone, there is- little doubt that adaptation is a causitive mechanism. However, the consistency of overall body form within a family, and often throughout an order, gives this bone some phylogenetic value. Thus, the differences in myology, tendinal attachments, and liganental bindings, which differentiate the sterna of the falconiforms appear to correlate as well with ancestry as with adaptive- modification. The cathartid type is not exactly matched in any other bird, but certainly it resembles that of the pelecaniforms some ciconiiforms', and procellariiforns. If Tenatonnis is' assumed to be a highly modified cathartid, then the likeness with these other orders is strengthened. Fisher (l-945:728) was aware of the similarity of the sternum of Ieratorni.s and Diomedeabut overlooked the point-by-point agreement with Fregata. Not only the sterna but also the coracoids and, to a lesser extent, the entire skeletons of these genera are sinilar. Such similarity suggests some elenent of comlnonancestry rather than adaptive nodification for a particular style of flight. (No one would assume that they did, in fact, have a commonstyle of flight.) The sternum of Sagittanius is matched fairly well by that of Cari.anw,but comparison with procellariiforms, pelecaniforms and storks seems more likely. Comparison with the cathartid suggests comnon ancestry of much the same antiquity as that of the other orders mentioned. The Accipitrid sternum cannot be used for the identification of subgroups although there have been such attenpts in the past Ilere again it is necessary to consider the writings of Howard and FALCONIFORMES 3(2031 Loye Miller in regard to the Aegypiinae. Howard (1932:49) noted that, "The characters of the sternum of the nodern vultures, as distinguished from the eagles, are as follows: (1) broad ventral nanubrial spine; (2) low carina; (3) short and broad sternocor- acoidal inpression. " Figure L69 shows a view of the sternum of Neogyps and several of the Aegypiinae. The coracoid sulci are widely Fig. 169. Dorsal views of anterior part of sterna of A. GypaEtus banb.atus, B. Aegypius monaehus, C. GApe eop"otheres, D: Neogyps e"Tans (2 specimens). separated on the nanubrial spine in Neogyps (range from well separated to in contact) and GypaEtus; those in Torgos and Aegypius are nearly in contact; Tnigonoeeps, Saneogyps, Neophnon, Necroeyntes show incipient lapping while in GAps, Peeudogyps, and Gypohiefat they are distinctly lapped. ?enathopius agrees with Tongoe and Aegypius in this detail. Most accipitrids show well lapped sulci, but in some specimens of Buteo and Leptodon, they are only slightly lapped. In fossil sterna of AquiLa it was noted that some showed no lapping and every transitional phase to that found in the modern species. On the bases of breadth ot manu- brial spine and small size of the anterior inner process on the 4 ( 204) M. JOLLIE sternocoracoid process Leptodon compares well with the aegypiin. is to evaluate. The relative depth-Gypohierar of the carina difficult That of Neophnon or can be included in the range of variation fbund anong-the typical accipitrids, whereas that of AquiLa is definitely lower than in the majolity of genera. Neogype is like Aquila in this respect and it resembles that genus- in alnost every way. Howardts last point on the relative size of the sternocor- acoid irnpression ov-erlooks the very smal1 fossa of Pandion and the overlapping series fron AquiLa through Necnosyrtes"- Gypohienar, to that of the Large aegypiins. Neophnon,- iira ileophnontope A more charatteristic feature of the sternum of the Aegypiinae is the forn of the yup?aeo?aeoideue scar. This is fo['ei along its posterior lateral nargin, and_the-ventral (nedial) margin liei close to the edgq of the keel. The shape of the scai in Tongoe is deternined in part by the pectonaLi,s muscle. Neophron tends toward the aegypiin outline, whereas ,Neo-phnontops and'Cypohierac are sinilar to the typical-accipitrid; i.e., they in this lack ihe lobe. Teyathopius-sagittanius. agrees with the aegypiins character as does also A type of sternum, limited to the subfamily Aegypiinae, cannot be characterized by arLyone feature or conbination of features, unless the species content of that subfanily is altered. The latter step would necessitate removal of Neogyps, The falconib sternum superficially resembles that of the accipitridae, and it does not find a better comparison elsewhere. However, this does not require a commonance-stry for these two faniliei as the conparison is still poor. The sternun of these two families, thusr-gives no clue to their ancestty, at least at this reading. OSTEOLOGY..MISCELLANEOUSSKELETAL PARTS Under this title the vertebral column, pelvis, humerus, ulna, manus, tibiotarsus, fibula, and foot will be considered, more by discuising features reported in the literature than in atternpting to delineite and evaluate new ones. Since any of the above can be described rather briefly the types characterizing the families of the falconiforms will be discussed together. Vertebral Column According to Beddard (1898:1L5), the total number of verte- brae in the spinal column of birds varies from 39 to 64, counting the pygostyle as one (based upon-Giebe1, 1866). According to- Parkbi.-(1Sb0:17), 'fMore than half of the tuelue thousand s-pecies known hiver otr an average, only forty vertebrae, even in the fhe African oslrich h'as-fifly-sia, and the-common swan, eirty-thnee."rUtio. NumericaL law is not very strict in birds; yet thosl six thousand species just mentioned have in a great majority just founteen cervici1s....'rueloe also is a conmon number for the -aoian-sae?um in the small high-type birds; and from ten to twelve vertebra in the caudal region is as a rule the number in in the falconiforms the embryo." The total number of vertebrae ' FALCONIFORMES 5(205) not including the pygostyle, varies from 39-41- among the cathar- tids, from 37-41 (usually 40) arnongthe accipitrids, 40 in Sagittarius,- and 39-41 (usually 40) among the falconids. Ordinarily the vertebral column is divided into a series of artificial segments: cervical, thoracic, lumbar, sacral, and caudal (fig. 170). The cervical vertebrae are those of the neck region, which extend posteriorly to (but not including) the vertebra bearing the first conplete rib. Thoracic verte- brae begin with the first complete rib and extend posteriorly to that vertebra bearing the last (floating or vestigial) rib. The lunbars bear no ribs and continue the series to the sacrals, which purportedly support the pelvic girdle. The caudals extend posteriorly flom the sacrals (but may be indistinguishable fron th-en) to the tip of the tail, the terminal caudal vertebrae fuse into a pygostyle. Part of the thoracic series, the entire lunbar, and sacral series and part of the caudal vertebrae are fused into the synsacrum (Table L2, fig.