Traits of Mystery Skull - Lab Report Example

            The mystery skull has the values of these indices recorded as 65, 23, and 90 respectively. The skulls were first grouped concerning the index of supra-orbital height and the specimens D, F, G, H, I, and B whose scientific names are given in chart 1 were found to be the potential identities of the mystery skull. The recorded values for the supra-orbital values were 70, 58, 58, 70, 66, and 70 respectively which were close to the mystery skull’s values of 65. The observation was then narrowed down to the index of nuchal area height and only three specimens (F, G, and I) bore a resemblance to our mystery specimen with recorded values of 21, 23, and 12 referenced against the mystery specimen’s value of 23.

            A reference was then made to the index of the condylar position and we only remained with G and I (Homo erectus and Archaic Homo sapiens respectively). To separate the two specimens the non-index characteristics were observed and the physical traits of the specimens that match the ones of the mystery skull #1 were noted. Specimen G has a thick eyebrow projection which is not specimen case I. In this case, the mystery skull is similar to specimen I. It is also observed that specimen G has a protruding face when compared to both specimen I and our mystery skull #1. A look at the shape of the eye orbits suggests that our mystery skull is the skull I since skull G has square eye orbits while I and the mystery skull both have oval eye orbits. The height of the nasal orbit is also shorter for g when compared to the height for G and the mystery skull #1.

            The taxonomic status of Mystery Skull #1 is Archaic Homo sapiens (specimen I). The reasons are as stated above in our discussion.

Mystery Skull #2

            The index characteristics; index of supra-orbital height, index of nuchal area height, and the index of the condylar position of the mystery skull #2 are recorded in chart 1 as 71, 37, and 44. A review of the index characteristics of the known specimens recorded in Chart 1 was made and various matches were made to single out the identity of our given specimen. The matching specimens with almost the same index of supra-orbital height as our mystery specimen were D, H, I, and B with the values recorded at 70, 70, 66, and 70 respectively, and matched against the value of 71.

            The classification was further narrowed down to the index of nuchal area height and three specimens matched our specimen’s value. These were specimens D, H, and B with values of 38, 37, and 40. Lastly, the index of condylar position was reviewed for the above three specimens and only one specimen matches the mystery skull’s specification by the mere proximity of the value. This was specimen D (Australopithecus africanus). There was no need to perform a physical characteristics review since we had narrowed down the selection to one specimen and thus the identity of mystery skull #2.

            The taxonomic status of Mystery Skull #2 is Australopithecus africanus (specimen D). The reasons are as stated above in our discussion.

Newly Found Skull

            In the classification of the newly found skull, the same procedure as before was carried out by first looking at the index characteristics and then the non-index characteristics. First, the index of supra-orbital height for the various known specimens is given as compared to the value recorded for the newly found skull and the specimens that match the descriptions grouped for further review. The index of supra-orbital height for the newly found skull recorded at 51 was compared with the values for the specimens and it was found that specimens C, E, F, and G matched this value closely at 49, 51, 58, and 58 respectively.

            A reference was then made to the index of the nuchal area to further narrow down the list. All the specimens were still found to match the 23 index of the nuchal area recorded for the newly found skull at 30, 16, 21, and 23 respectively for specimens C, E, F, and G. Then concerning the index for condylar position for the newly found skull, it was found that two out of the four specimens matched the value of the newly found skull which was recorded at 57. The values for two remaining specimens E and F were 58 and 51 respectively.

            To determine from the two specimens which one is our newly found skull a comparison of the physical characteristics of each was observed and compared with the physical traits of the newly found skull. The only distinguishable feature that was in the newly found skull and the one for specimen E was the protruding sharp-edged cheekbone while for specimen F it was protruding but rounded when viewed from the front.

            The taxonomic status of the Newly Found Skull is Australopithecus robustus (specimen E). The reasons are as stated above in our discussion. The table below summarizes the classification.          

Specimen

Identity

Distinguishing Physical Characteristics

Mystery Skull #1

Archaic Homo sapiens (I)

Non-protruding face, non-thick eyebrow projections, oval eye orbits

Mystery Skull #2

Australopithecus africanus (D)

Newly Found Skull

Australopithecus robustus (E)

protruding sharp-edged cheekbone