. Annals of the South African Museum = Annale van die Suid-Afrikaanse Museum. Natural history. FOSSIL BOVEDAE FROM LANGEBAANWEG 277 that of Damalacra neanica. There can be little doubt that the two alcelaphine species are closely related. It is interesting that D. acalla has many characters which appear to be primitive just as in D. neanica, but hardly any which are specialized. Primitive characters are the transversely straight parietofrontals suture, the supraorbital pits not set wide apart, most of the characters of the horn-cores, the fairly long brain- case and its not very inclined roof,
. Annals of the South African Museum = Annale van die Suid-Afrikaanse Museum. Natural history. FOSSIL BOVEDAE FROM LANGEBAANWEG 277 that of Damalacra neanica. There can be little doubt that the two alcelaphine species are closely related. It is interesting that D. acalla has many characters which appear to be primitive just as in D. neanica, but hardly any which are specialized. Primitive characters are the transversely straight parietofrontals suture, the supraorbital pits not set wide apart, most of the characters of the horn-cores, the fairly long brain- case and its not very inclined roof, and the characters of the cheek teeth. Fig- ure 36 shows the difference in horn-core compression between D. acalla and D. neanica, and also that D. neanica has different cranial proportions in the form of a shorter braincase and a lower and wider occipital surface. The extant Damaliscus dorcas, shown on the same figure, has cranial proportions similar to Damalacra acalla, but rather small horn-cores and a relatively narrow width across the anterior tuberosities of the basioccipital. Figure 37 shows cross- sections of Damalacra horn-cores. Anteroposterior diameter at horn core base Medioiateral diameter at horn core base Width across horn core bases Braincase length Skull width across mastoids Occipital height Width across anterior tuberosities of basioccipital Width across posterior tuberosities of basioccipital. 80 90 100 110 Fig, 36, Percentage diagram of skull measurements in Alcelaphini, The standard line at 100 per cent is for seven Damalacra acalla from bed 3aS. The other continuous line is for six D. neanica including LI2694A, and the dashed line is for four male Damaliscus dorcas. Not all measurements were available on all the fossils. Among the female remains of Damalacra only a horn-core and a frontlet, L40126A and L40275, are thought to be of D. neanica. Another two are thought to be definitely of D. acalla; these are the cranium L40225 and the left horn- core LI056
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectnaturalhistory, booky
