Endocast of Sambungmacan 3 (Sm 3): A new Homo erectus from Indonesia

A new fossil calvaria, Sambungmacan 3 (Sm 3), described in New Fossil Homin id Calvaria From Indonesia-Sambungmacan 3 by Marquez et al., this volume, y ields one of the most advanced and complete endocasts yet recovered from Ja va. This communication provides a thorough interpretation of the external a natomical landmarks observable on Sm 3. Using computer tomography (CT) and traditional morphological measurements, our comparative paleoneurological a nalyses show that while Sm 3 has a mosaic of features that are similar to b oth Indonesian and Chinese H. erectus, it also possesses significant charac ters reminiscent of later hominins. These include a greater degree of asymm etry characterized by a possible left-occipital, right-frontal petalial pat tern, left-right volumetric cerebral asymmetry, and marked asymmetry in Bro ca's cap. Moreover, the frontal lobe offers a more rounded, shortened appea rance in contrast to the flat, elongated appearance of other Indonesian fos sils (e.g., Sangiran 17). Another unique trait is exhibited in the transver se plane where the widest breadth of Sm 3 occurs more superiorly than in ot her Indonesian H. erectus. Thus, the endocast of Sm 3 presents a unique mor phology not seen previously in the hominin fossil record. While the strong modern human characteristics in this endocast may not represent a particula r ancestry, they do allow us to recognize a new dimension of the remarkable variation in Indonesian Homo erectus. Anat Rec 262:369-379, 2001. (C) 2001 Wiley-Liss, Inc.