Physical Cranial Characters of Wajak Man

Abstract

Human fossils from Wajak, or better known as Wajak Man which is noted as Wajak 1, have been discovered by von Rietschoten in 1888 during exploration prospecting activities at the marble mine area in Tulungagung. The Wajak 1 found in cave sediments during disorganized excavation, therefore the stratigraphic position of the fossil was uncertain. Until this time, since the discovery of the fossil, not many study and publications have been performed on the fossil of Wajak 1. For this reason, this research attempted to compare Wajak 1 with Homo erectus fossils from Ngandong, Sambungmacan, and Sangiran to understand the presence of a linearity pattern based on anatomy of the physical cranial characters. The research was conducted through qualitative analysis by comparing the anatomy of all samples, and quantitative analysis by measuring some biometric parameters of cranium which then processed by statistical methods. Based on PCA analysis, the fossils of Ng 9, Ng 10, Ng 11, Sm 1, Sm 3, Sm 4, Sn 17, Ngawi 1, and Wajak 1 have some kinship based on two principal components as a variable that mostly contributed. Particularly, the specimen of Wajak 1 has the furthermost kinship with other fossils based on maximum cranial length and minimum frontal breadth. Based on these parameters, the Wajak 1 has the largest size in comparison with other fossil samples. The fossil Ngawi 1 and Sm 3 have a close relationship because both of the samples have a smallest size among others, as indicated by their maximum cranial length, minimum frontal breadth, parietal chord, and occipital chord. The specimens of Ng 9, Ng 10, Ng 11 closed to one another and formed in one group, while Sm 1 and Sm 4 close to Sn 17 and form another group. Ng 9, Ng 10, and Ng 11 have a greater values on four parameters compared to the specimens Sm 1, Sm 4, and Sn 17. The result of cluster analysis shows the cluster pattern similar to PCA as shown in the dendrogram. Based on comparative anatomy, the Wajak 1 has most rounded shape and largest cranium. Another different could be seen visibly in the supraorbital torus which is thin and curve tends to follow the shape of orbital. A prominent supraorbital torus is a character belongs to Homo erectus was observed in the specimens Sm 1, Sm 4, Sn 17, Ng 9, Ng 10, Ng 11, Sm 3, and Ngawi 1, but it was not observed in Wajak 1. So, it could be concluded that Wajak 1 is belongs to Homo sapiens which has a characters no prominent supraorbital torus, most rounded form and largest size among other specimens. Keywords: Wajak Man/Wajak 1, comparative anatomy, Principal Component Analysis (PCA)