The segmented endocast comprises the calvarial surface up to approximately the coronal suture, left of endobregma missing small portions and on the right side enclosing also parts of the frontal lobe, both occipital lobes, both cerebellar lobes, the entire right temporal lobe and also most of the left temporal lobe only missing very anterior parts.
The volume of the preserved natural endocast has been determined to be 378 cm³ and the total endocranial capacity has been estimated to be 450 cm³, using Sts 5 as reference-specimen. This estimate is significantly smaller than the first estimate by Dart (1962, 480 cm³) and larger than the more recent estimates of Holloway (1972, 435 cm³) and Conroy et al. (1990, 425 cm³). The sample mean of endocranial capacity for Australopithecus africanus thus increases to 454 ± 32 cm³ (n=7).
Beside the endocranial capacity, other qualitative and quantitative data regarding the shape of the endocast were examined. In occipital view, the endocast is round in shape, in superior view egg-shaped. In general, the endocast of MLD 37/38 is lower and wider than that of Sts 5, StW 505, Sts 71 and Taung. Only Sts 60 is even more lower and wider than the endocast of MLD 37/38.
The four measured distances (projected measurements of the cranial base, after Falk et al., 2000) for MLD 37/38 lie well within the range of the other available Australopithecus africanus specimens. Endocasts of Australopithecus africanus are more similar to those of Homo , while Paranthropus endocasts are more ape-like in these metric aspects. Because a handful of distance measurements provide only restricted information of the shape, the shape of endocasts should be analyzed in the future using geometric morphometrics (see Neubauer et al., 2006).
Other qualitative aspects of endocasts are convolutional details and asymmetries. While other natural and artificial endocasts, regardless if real or virtual endocasts, can show detailed convolutions, no such convolutional details could be found on the endocranial surface of MLD 37/38. Also, the very controversially discussed lunate sulcus is not detectable on this specimen. The slight displacement of the right parietal bone over the left causes small asymmetries of the endocast. A small right occipital petalia can be seen.

Furthermore, endocasts give evidence of venous drainage from the brain and arterial supply to the internal table of bone and the dura mater. MLD 37/38 shows a well-developed lateral venous drainage system (transverse and sigmoid sinuses) on both sides while there is no evidence for an enlarged occipital-marginal sinus system. Except for the juvenile Taung fossil, all known Australopithecus africanus specimens exhibit this pattern of cranial venous drainage. In contrast to the condition in Australopithecus africanus, enlarged occipital-marginal sinus systems are known in high frequencies in Australopithecus/Paranthropus robustus , Australopithecus/Paranthropus boisei , and Australopithecus afarensis and have been used as a claim to robust australopithecine membership (Tobias, 1968; Falk and Conroy, 1983; Kimbel, 1984; Falk, 1986; White and Falk, 1999; Falk et al., 2000; Holloway et al., 2002).
Internal blood supply of the brain is not detectable on an endocast but meningeal vessels frequently leave imprints on the internal table of bone. Several branches of meningeal vessels could be detected on the left side of the endocast of MLD 37/38. On the right side only rudimentary branches can be seen because the cranium broke apart on the boundary between fossilized bone and the natural endocast in this area. While one branch on the left side gives evidence that the middle third of the braincase was supplied by the external carotid artery through the foramen spinosum, another branch on the ride side stems from the orbit and therefore originates from the internal carotid artery. Because statistical analysis (n= 43 apes, Chi2=18.92, df=1, p<0.001, Falk, 1993) showed that Falk’s pattern A (blood supply by meningeal vessels originating from the internal carotid artery with an increasing extent of supply by the middle meningeal artery from A1 to A4) or E (blood supply alone by the middle meningeal artery originating from the external artery) in one hemisphere strongly predicts the same pattern in the other, it can be concluded that there was blood supply from both, the internal and external carotid artery to the middle third of the braincase (pattern A2, A3 or A4).
Furthermore, the stone matrix was removed from some apertures and foramina so that they can be followed from outside inwardly. Parts of the right orbit were preserved within the stone matrix. The superior orbital fissure was found to be round in shape and therefore should be called superior orbital foramen instead. This feature in MLD 37/38 conforms to the character state in African apes, Australopithecus afarensis , and Australopithecus africanus in contrast to humans and robust Australopiths that show elongated, comma-shaped superior orbital fissures. The crescent of foramina (superior orbital fissure/foramen, foramen rotundum, foramen ovale, foramen spinosum) in MLD 37/38 has the same morphological condition as the other Australopithecus africanus and Australopithecus afarensis specimens.
This work demonstrates that Virtual Anthropology, using biomedical imaging and geometric morphometrics, reveals features of precious fossil hominids that would otherwise be inaccessible using traditional methods.