Spotlight on Students: Understanding Paleoanthropological Study (Part 2)

The following pieces are written by students who were enrolled 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 were asked to comment on a recent hominid discovery, which the paleoanthropological community was at odds about.  The following works are the students who provided the most accurate submissions.  Please show your appreciation for their hard work through the comments.

By: Rayven Stokes 

Being a paleoanthropologist, I have acquired a unique set of research skills that I am glad to share with the public.  573 Local News has asked me to share my professional opinion on the recent discovery of a new hominid species. There is great confusion on how to classify this newly found hominid ancestor into our human lineage. My goal today is to help end the confusion between which genus this species belong to. There are many similarities between the Australopithecus and the Homo genera, but there are also distinctive differences. I have developed my research and have picked specific pieces of morphological evidence that allow me to easily classify different hominid species into different genera.

The Australopithecus genus is also named the “Southern Ape Man”, a term coined after Raymond Dart due to some prejudicial reasons.  It is known to be the start of the human lineage, meaning that humans came from this long line of early hominids from approximately two to three million years ago (Welsch et al. 202). Australopithecines have distinctive morphological differences that make them different from their primate ancestors. Australopithecines had a larger cranial capacity, although their brain size was only 35% of the human brain today, but this was still larger than those of its primate ancestors (Welsch et al. 199). The second morphological characteristic to focus on is the build of Australopithecines you will notice they were tall and gracile, meaning they were slim and had a slender build. We can also take notice of their hands that were capable of gripping things and creating unique tools; we know this through the discovery of fossil stone flakes and several mammalian remains that display cut marks and signs that several members of this genus put their brains and muscles together to process foods (Welsch et al. 199). The last and major morphological feature is their bipedal stature. Although they were bipedal, meaning they could walk on two feet and stand upright, they still had long arms that showed they were still partially arboreal, meaning they still probably lived in trees. (Welsch et al. 199)

               Now I would like to shift the focus to our human ancestor, the Homo genus, and the morphological characteristics that are most important to look at when classifying a hominid species. The Homo genus poses many characteristics of the Australopithecines considering they come from the Australopithecine lineage, but to be classified into the Homo genus you must acquire specific traits one being their large cranial capacity. The Homo genus brain was 50% the size of the human brain today (Welsch et al. 202), which could have coined them their nickname “The Wise One”. Their brain size is bigger than any Paranthropus or Australopithecus genus. It is known that the Homo habilis brain possessed the part in the human brain today that allows for speech (Welsch et al. 202). The intelligence of the Homo species is displayed in many of the stone tools found, Olduwan tools. The Homo genus had fingers that were slightly curved and strongly built, allowing for precision when building tools (Welsch et al. 202).  In the early Homo genus, the Homo habilis had no sagittal crest, they had interesting teeth large incisors but smaller post canine teeth and a narrower tooth row (Welsch 202).

I have chosen to bring to your attention very distinctive morphological features of the Australopithecus and the Homo genus, so that you can understand that they are very similar but yet very different. It is very important to pay attention to the cranial capacity of the hominid species because that indicates how much that species is capable of doing, for example, their hunting techniques, their ability to survive, communicate, and construct. It is important to look into their size and body build that can give us insight on how early hominids lived, there activity level, their musculature, etc. It is important to look at their hands and feet to determine how the shape and form allows for their precision and what specifically they could have used their hands for, specifically in regard to creating material culture.  I take note of their teeth to identify what they ate, which provides insights into their diet.  And lastly, we must look at their stature as that gives us insights into their mobility patterns. These are all important pieces of morphological evidence that must be looked into to further classify a hominid ancestor.

We can use this information to better classify this newly found hominid species. The cranial capacity of the Australopithecine is fairly smaller than the cranial capacity of the Homo genus. The Australopithecine brain is 35% the size of the modern human brain were as the Homo genus brain is 50% the size of the human brain. The Homo genus possessed the same part of the brain that modern humans have that allow us to speak to one another, which indicates that the Homo species may have been capable of rudimentary speech. Despite the obvious cranial capacity, both of these genuses had the capability of creating advanced stone tools which means they had hands that can grip things. The Homo species created stone tools that were far more advanced than the Australopithecus. Their tools named Olduwan tools “were made by striking the edge of a stone with a hammerstone, which produced many hammerstones they also had sharp flakes that allowed for precise cutting techniques for food and other objects.” (Welsch et al. 202).  The creation of this tool sounds tricky, but it was able to be done because the Homo genus had fingers that were slightly curved, allowing them more movement and precision as opposed to those in the Australopithecus genus. Looking at the build of the Australopithecine you will see that they were a tall species with a slender build you could say they were “tall and lanky” they were not as muscular or robust as the Homo species, the Homo genus was also quite shorter. The early Homo species had smaller post canine teeth and narrower tooth row than is seen in the Australopithecus (Rightmire). Lastly taking a look at their locomotion the Australopithecus is known to be more ape-like it is still bipedal, but they have very long arms much like its primate ancestors making them very good climbers and they could be arboreal where the Homo genus is fairly shorter than the Australopithecus but still had very long arms they were still bipedal and lived on the ground but they were probably really good climbers (Study.com).  It easy to say that the Australopithecus is a more ape-like hominid compared to the Homo genus.

I hope that my research has helped clear up some of the debate as to where this hominid species should follow. I have outlined and discussed important morphological evidence that you must pay attention to in order to classify a hominid a species ranging from their cranial capacity to their locomotion and build. Each characteristic plays a huge part in where this specie will fall in our human lineage so keep that in mind when conducting your research.

Works Cited

Rightmire, G. Philip. “Homo Habilis.” Encyclopedia Britannica, Encyclopedia Britannica, Inc.,

https://www.britannica.com/topic/Homo-habilis.

Study.com, Study.com, https://study.com/academy/lesson/australophithecus-definition-characteristics-

Welsch, Robert L., Luis A. Vivanco, et al. Anthropology: Asking Questions About Human Origins,

Diversity, and Culture. Oxford University Press, 2017.

By: Cole Bax

          

              In order to determine whether a specimen is hominid (human), a paleoanthropologist must first focus on at least three physical/morphological features in order to guarantee a specimen is hominid. The three characteristics I will focus on in this assignment are: foramen magnum placement on the cranium (skull) in relation to posture, the shape of the pelvis, and a close look at the canine/premolar-3 shearing complex. I chose these physical/morphological features because they specifically demonstrate early hominid features. A foramen magnum is the hole in the base of the cranium (skull) where the spinal cord enters the skull (Welsch et al. 198). When the foramen magnum is located at the base of the cranium (skull) then the specimen more than likely used bipedal locomotion (walked on two legs). If the foramen magnum placement rose further up the skull, the specimen would have slouched forward until it was walking on four limbs. The shape of the pelvis is looked at because this determines whether the specimen was upright. The top half of the pelvis will be inspected to determine if it is short or long, and the same will be done for the bottom half. A reduced canine/premolar-3 shearing complex, is when the lower first premolar tooth is somewhat sharpened or flattened from rubbing against the upper canine as the mouth closes (Welsch et al. 198). The occurrence of this phenomenon indicates the changes undergone in the structure of the jaw in our specimen due to the food resources that are easily harvested and do not require a lot of energy to gather.    

        Australopithecine were gracile (slender bodied) and only stood between three foot eleven inches and four foot seven inches tall (Welsch et al. 199). The male and female Australopithecus had very different bodies. The males were much larger than the females, and this difference was known as sexual dimorphism. In Australopithecus, the foramen magnum was anteriorly (at the base of the skull) sited, but without the foramen’s forward inclination (Kimbel 1). This indicates that the Australopithecus were not only terrestrial, but like their primate ancestors, they were also arboreal. The shape of the pelvis that would have belonged to an Australopithecus would likely be very similar to its primate ancestors. The climbing ability the Australopithecus possessed indicates that the pelvis was still elongated on both ends. The bottom of the pelvis will be longer than the top of the pelvis due to the Australopithecus’s ability to also walk bipedal. The top of the Australopithecus pelvis will be slightly shortened due to the switch in bodyweight positioning on the pelvis. Due to a more terrestrial lifestyle the type of food changed, and therefore the structure of the Australopithecus’s jaw and teeth changed. The changes in jaw shape caused teeth to rub differently and therefore be reshaped. For example, the canines are either sharpened or flattened down by constant rubbing against the first lower premolar tooth. Since the Australopithecus also are still partially arboreal, their teeth give off a resemblance of a mix between human and primate tooth structure.

             The genus Homo emerged out of the australopithecine lineages sometime between three and two million years ago (Welsch et al. 202). The foramen magnum placement in homo specimens are typically always located very low on the cranium (skull), letting our specimen stand totally upright with zero heavy slouch. The lowered foramen magnum also makes the spine more straight rather than curved back similar to primates that walk on their upper limbs. Since the foramen magnum is now as low as it gets, our specimen is completely bipedal and sticks to terrestrial living entirely. This switch to complete terrestrial living causes the pelvis to shorten at both the top and bottom. With zero reason for climbing, the bottom of the pelvis is shortened in order to utilize the full benefits of bipedal locomotion. The weight of the upper body is now weighing down on the top of the pelvis which is constantly causing it to compress into itself and therefore not only becoming shorter, but also more stabilizing for bipedal motion. The positioning where the hip connects also changes on the pelvis, due to the straight up and down position of the femur.  Due to living only a terrestrial lifestyle for some point of time, the structure of the homos jaw and teeth also changed. The changes in jaw shape caused teeth to rub differently and be reshaped. This is known as the canine/premolar-3 shearing complex.  For example, the canines are rubbed flat with very little point to them.  This change is not only due to jaw structure, but also the food being consumed in terrestrial living. The transition from the use of sharp, pointy teeth to flat teeth may also be caused from the lack of protection once needed. Now that the specimens are predominantly bipedal, they can view predators from further away and will likely run instead of fight, thus doing away with the need for sharp teeth as protection.

            Australopithecine and the genus Homo have similar characteristics when it comes to their features. Australopithecine tend to either slouch forward or even sometimes walk on all fours, while the genus homo is strictly accustomed to bipedal locomotion. The posture and occasional walking on all fours by the Australopithecus are due to the foramen magnum being slightly higher than the genus Homo. In fact, the genus Homo has no slouch and always walks on two limbs thanks to the foramen magnum being located very low on the cranium. The shape of the pelvis differs between the two due to the lifestyle in which they each lived. The australopithecine were predominantly climbers with only some bipedal locomotion. The bipedal locomotion in both specimens cause their pelvic bones to be shorter on the top half. However, the lower half of the pelvis was drastically different in shape between the two. The bottom half of the australopithecine pelvis is longer than the one of the genus Homo, and this is due to the climbing ability that is still instilled in the australopithecine.  

Work Cited / Bibliography

Welsch, Robert Louis, et al. Anthropology: Asking Questions about Human Origins, Diversity,     

            and Culture. OXFORD UNIVERSITY PRESS, 2019.

Kimbel, William H, and Yoel Rak. “The Cranial Base of Australopithecus Afarensis: New     

           Insights from the Female Skull.” Philosophical Transactions of the Royal Society of

           London. Series B, Biological Sciences, The Royal Society, 27 Oct. 2010,

           https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2981961/.