Spotlight on Students: Hominid Discoveries

The following is written by Srikavi Premnath, a former student in SA 202: Introduction to Anthropology.  In one of the course assignments students were provided a scenario where they had to imagine that they were paleoanthropologists who just discovered a new hominid species, and they had to explain what parts of the body they would focus on to make the case that their new species was indeed part of the hominid lineage.  Please show your appreciation for Srikvai's hard work through the comments.

By: Srikavi Premnath
 

During my fieldwork in the African continent, I discovered the latest hominid species, which I named Earthensis megalisis. The species featured a less-pronounced sagittal keel, pelvis, and unique hand structure. My team and I happened upon this species while studying the ancient habitat of the group that had inhabited the region Megallion. Throughout this report I will explain the cranium, the pelvis, and the two hands I had uncovered along with my team. These structures were chosen from the overall skeleton to compare the structural aspects to the modern human. Additionally, these hominid remains provide insight into the various species leading to the modern human species and in this report, I will explore these comparisons.

We discovered the cranium of Earthensis megalisis first. The cranium featured a sagittal keel, which is a “raised area in the mid-cranium” (Welsch, Vivanco, Fuentes, 2017). The sagittal keel has become even less-pronounced in the modern human, perhaps only viewed by the sagittal suture. I have learned from my anatomical coursework that the sagittal suture connects the bones of the two halves of the cranium. I chose the cranium, specifically the sagittal keel, to examine because of the possible connection between the structure of the sagittal keel and the present sagittal suture. The possible connection seen in the example, “Homo erectus exhibited sagittal keels in some of the fossils found. These fossils were discovered in Africa and among many other regions of the world” (Welsch, Vivanco, Fuentes, 2017). Although the cranium may suggest the species relates to Homo erectus, the pelvis discovered may suggest another relative.

The pelvis recovered from the site exhibited a pronounced iliac crest. I recalled from my anatomy coursework the pelvic bone exhibits certain differences in features such as width and overall size. The width and size contrasts between males and females. “Modifications to the pelvis creating a stabilizing pelvis” (Welsch, Vivanco, Fuentes, 2017) have contributed to the movement of the species as well. These pelvic modifications aided in the ability to move more efficiently. The sexual dimorphism present suggest the relation to Australopithecus africanus, which had, “a pelvis better for bipedalism than that of Australopithecus afarensis,” (Welsch, Vivanco, Fuentes, 2017). This provides evidence for improvement in mobility with the change in pelvic structure. Australopithecus africanus additionally possessed, “pronounced sexual dimorphism,” (Welsch, Vivanco, Fuentes, 2017). The present pelvic structure also includes differences in males and females. My anatomy coursework noted the key factor in the differences are the ability of women to bear a child and the structure in the pelvis of women supplements the child-birth process. While examining the pelvis Australopithecus africanus may seem to be a distant relative to Earthensis megalisis; nevertheless, the hands must be examined to ensure this species can be considered a distant ancestor to humans.

The hands were discovered after the pelvis in the excavation process. The hands most importantly suggest dexterity improvements among various lineages. The hands produce the ability to hold items, create objects, and much more. Homo habilis could relate to Earthensis megalisis possibly because they featured, “a gripping hand for tool use,” (Welsch, Vivanco, Fuentes, 2017). The ability to hold a tool suggests the dexterity improvements I had discussed. The present hand structure consists of carpals, metacarpals, and phalanges according to my anatomy coursework. These divisions lend to the overall dexterity and ability to perform multiple tasks such as writing and playing an instrument. I should note Homo habilis is among the various species which posses the advanced capabilities of the hand. Australopithecus sediba whose, “grasping hand suggests possible tool use,” (Welsch, Vivanco, Fuentes, 2017). The hands discovered from Earthensis megalisis could relate to either Homo habilis or Australopithecus sediba; however, further investigation and discovery of fossils will provide more definite answers.

In conclusion, many fossils led to the recovery of Earthensis megalisis. The cranium, pelvis and hands were examined further to find distant relations to other recorded hominid characteristics. The sagittal keel of the cranium reminded me of the sagittal suture of the present. Homo erectus possessed the sagittal keel in some of the fossils uncovered. Next, the pelvis provided insight into sexual dimorphism and contrasting abilities due to pelvic structure. Australopithecus africanus possessed sexual dimorphism characteristics and greater mobility. Finally, the structure of the hands provided clues to understand the advanced dexterity. Homo habilis and Australopithecus sediba had the ability to hold objects. The fossils were chosen to suggest Earthensis megalisis may be a distant relation to the present human.

Reference

Welsch, R. L., Vivanco, L. A., & Fuentes, A. (2017). Anthropology: Asking Questions About Human Origins, Diversity, and Culture. New York, NY: Oxford University Press.