Meganthropus

Before formal naming or identification, this organism was known as the following on this wiki:
**The mystery ape of Pleistocene Asia**

## Statistics

### Synonyms

*Homo erectus palaeojavanicus
Homo erectus wushanensis
Pithecanthropus dubius
"M. africanus"*
*"Paranthropus" palaeojavanicus*

### Weight

400-600 pounds (181-272 kilograms) (formerly)

### Diet

Omnivorous?

*Meganthropus* is an extinct genus of non-hominin hominid ape that lived during the Pleistocene in Indonesia.

## History

   A fragmented mandible from Longgupo with a 4th premolar and the 1st molar was discovered from the *Stegodon*-*Ailuropoda* fauna. Wearing on the enamel made it difficult to classify, with Russell Ciochon et al. (1992) brought to identify it. Previously, the jaw had been classified as *Homo erectus* and ape, historically called *Homo erectus wushanensis* or the Wushan Man. The jaw is 1.8-2 million years old and smaller than any orangutan. It was compared with apes from Lufeng, where *Lufengpithecus* was found to fit the size and morphology, but could not have been this ape because it is much older. Human tools found with the mandible supported a human classification, with most leaning towards Asian *Homo erectus*; this was later found to be incorrect due to incorrect morphology and size. Ciochon has noted *Lufengpithecus* may be a likely conclusion, but also proposes the teeth represent a more-primitive-than *Homo erectus* hominin similar in size to a chimpanzee.

Ciochon searched more collections for outlier teeth. From the Guangxi Natural History Museum, their collection of primate teeth from Mohui cave yielded 15 *Gigantopithecus* teeth, 10 cf. *Pongo* and 8 outliers, all from the same fauna as the original mandible. Ciochon speculates this ape is an ancestor of *Lufengpithecus* or an unknown genus. Previous *Homo erectus* and Gigantopithecus interactions documented by Ciochon in Other Origins: The Search for the Giant Ape in Human Prehistory (1990) are now speculated to be from this new ape. *Homo erectus* occurrences from similar sites also likely represent this same taxon, with stone tools recently added to the site and not referable to this hominid taxon.

By comparing well-known Asian *Homo erectus* occupation sites finds that they probably stayed to the grasslands, and did not sink into the dense rainforests that held the mystery ape. However, it is unknown if they did not, or could not go into the rainforests. This concept is further supported by a lack of African or Asian subtropical/tropical human occurrences. Teeth from Jianshi and Tham Khuyen, labeled as *Homo erectus*, *Meganthropus* or *Australopithecus* likely also represent the mystery ape, with a 2009 paper referencing an unidentified tooth from Sanhe Cave also likely referable.

Ciochon also references the material referred to the dubious ape *Hemanthropus*. Most are worn atypical orangutan teeth, but Ciochon found several small teeth closely resembling the teeth from Mohui, so it is likely Ralph von Koenigswald was the first person to handle this taxon. Ciochon concludes that Asia likely had a greater ape diversity than Africa at this time, coexisting with *Gigantopithecus*, *Pongo* and gibbons. Wang and Ciochon et al. are set to identify this ape, with Wang's further excavations at Hanoi, Jianshi, Beijing, Bubing Basin and Frankfurt and museum collection searches taking place. *Meganthropus* satisfies these criteria.

## Description

* Meganthropus cranial restoration.png**Credit: Clumsystiggy on DeviantArt.**
* Meganthropus portrait.png**Credit: Clumsystiggy on DeviantArt.**
1/2Sanigran 6a and 914-17 lack the P3 honing complex and are non-sectorial. They are more similar to the P4's reduced crown height with a prominent bicuspid metaconid and a buccolingually-oriented crown major axis. With these, Meganthropus is similar to Plio-Pleistocene hominins, which the authors note may argue for it being a hominin, but is also similar a canine reduction trend seen in *Indopithecus*, especially *Gigantopithecus* and even to *Ouranopithecus*. Trinil 11620 was debated to either be *Pongo* or *Homo*, but may be *Meganthropus* due to a low value in line periodicities. Meganthropus has "absolutely large teeth" with a mandibular corpus with a thick, rounded inferior border, a alrge extramolar sulcus, strong lateral prominence, premolars that are molarized with low crowns and coarse wrinkling that converges to the occlusal surface's center. Ape-like occlusal macrowear patterning, peripherally-distributed thickened molar enamel, an EDJ that is lowly-crowned and has short dentine horns, a slender pulp with high horns and lower crown-root surface area further differentiate *Meganthropus* from *Homo*. From the penecontemporaneous *Homo erectus*, it differs by a cingulum-like protostylid in the enamel and the EDJ; this is commonly seen in *Australopithecus* and *Paranthropus*, with occlusal wear patterning, thicker peripheral enamel, a lower EDJ topography, a slender pulp chamber and vertically-elongate pulp horns differentiating them from *Meganthropus*. It differs from *Pongo* via a laterally-positioned molar dentine horns, a slender pulp chamber and a cingulum-like expression of the protostylid. It differs from *Gigantopithecus* by having wider molars with high slender cusps and squared crests, a small cuspule, larger midline cusps, a distinct protostylid, a weak buccolingual mid-crown waisting, thinner occlusal enamel and a lower EDJ topography. *Meganthropus* is most similar to *Lufengpithecus*, possibly being closely related. However, a full phylogenetic tree will require more knowledge.

## Classification

Since discovery, *Meganthropus* has had a long and difficult classification. The remains, for long time, were though to be invalid, using the name *Meganthropus palaeojavanicus* as a type of nickname to refer to the unique specimens. Mid 2000's phylogeny and taxonomy of *Meganthropus* was uncertain, but most thought the ape to have been related to *H. erectus* in some way. Names such as *Homo* palaeojavanicus and *Australopithecus palaeojavanicus* were proposed, which are now seen as unlikely designations. A robust skull labelled SK49 discovered in 1948 in Swartkrans was briefly named "*Meganthropus africanus*", now as *Paranthropus robustus*. Some specimens were found alongside evidence of tool use, hence the name *H. erectus palaeojavanicus*, which may fall from use.

*Meganthropus* was thought to have been able to wield and use tools, which is why this upright-walking hominid is currently thought to have been a population of massive *H. erectus*. The skull of *Meganthropus* was usually considered humanoid, but is only known from partial cranial elements, mandibles and teeth. Some state the remains fall in range of known *H. erectus*, with some proposing a new species: *Homo paleojavanicus* or *Homo erectus palaeojavanicus*, based on basalmost positioning and low cranial capacity. Some, in favour of this theory, cite the opposite: saying there are no distinctions to be made. In 1953, *Meganthropus* was considered a robust australopithecine based off of the mandibles and teeth recovered. It was later interpreted as *Australopithecus africanus*. Based off of the size, researcher Grover Sanders Krantz stated that *Meganthropus* was outside of the *H. erectus* size range.

As more remains of the animal were found, *Meganthropus* is now considered a sort of 'mystery ape', closely related to that of *Lufengpithecus*, which was proposed in 2009 by Russel Ciochon. Ciochon still considered *Meganthropus* as conspecific with *H. erectus*. In 2019, research proved that *Meganthropus* is a valid genus of ape, distinguished from *Pongo* and *Homo* from various features. *Pithecanthropus dubious* was considered a junior synonym of *Meganthropus*. This would insinuate that *Meganthropus* was a type of, or just outside Ponginae, which would include other apes such as the widely-known *Gigantopithecus* and *Pongo*.

## Paleoecology

Sanigran and Trinil were a variety of mixed and temporally-shifting ecosystems that bore a mix of open woodland and dense forests supporting large forms like *Meganthropus* and arboreal monkeys such as *Macaca fascicularis* and *Trachypithecus cristatus*. *Sivapithecus*, *Khoratpithecus* and *Lufengpithecus* were also present in South-Southeast Asia during this time. However, *Meganthropus*, dentally, appears to have been the last based on low cusped and wrinkled molar crowns, a squat EDJ, an extended protostylid and a slender pulp chamber. *Meganthropus* was part of 2-3 large ape lineages that may have been influenced by *Homo erectus* expansion, palaeoenvironmental changes or competition with *Pongo* and *Gigantopithecus*, maybe a combination of these. *Meganthropus* does not survive past the Middle Pleistocene, leaving only *Pongo* as surviving Ponginae.

In Longgupo it was contemporaneous with *Gigantopithecus*, *Ailuropoda microta*, *Sinomastodon*, *Equus yunnanensis*, monkeys, rhinoceros, beavers, bears and tigers. At this point, the Yangtze River had not yet formed and a worldwide state of climate deterioration had just passed. *Meganthropus* lived in moist lowland tropical forests dominated by bamboo in the *Stegodon*-*Ailuropoda* fauna.

## Notable Specimens

* *Meganthropus* A/Sangiran 6: A large jaw fragment discovered by Gustav von Koenigswald in 1941, the holotype of *Meganthropus*. He was captured by the Japanese in World War II, managing to send a cast to Franz Weidenreich, who described and named the specimen in 1945. At this time, it was the largest hominin mandible known and was struck by the fossils size. Having about the same height as a gorilla but a distinct form, this jaw is unlike other anthropoids who reach the greatest height at the symphasis. Instead, the jaw reaches peak height at the first molar, M1. During study, Weidenrech considered acromegalic gigantism, ruling it out due to not having signature features such as a large chin and proportionally small teeth. Never making a size estimate, he instead states the animal would have been 2/3 the height of *Gigantopithecus*. If scaled to a robust man or erect hominid, it may have reached 8 feet (2.44 meters) tall and 400-600 pounds (181-272 kilograms). Apparently, Grover Krantz used this specimen in a skull reconstruction, measuring 21 centimeters (8.3 inches) tall.
* *Meganthropus* B/Sangiran 8: A jaw fragment found in Indonesia named by Marks in 1953, around the same size and shape of the first mandible. This specimen was severely damaged, repaired by a Japanese/Indonesian team. This individual could have been smaller than *H. erectus*, having several unique traits found in the first specimen but not *H. erectus*. No size estimates have been hypothesized, as-of yet.
* *Meganthropus* C/Sangiran 33/BK 7905: The most tenuous jaw, discovered in 1979. This fragment retains several traits from previous mandibular finds.
* *Meganthropus* D: A mandible and a ramus discovered in 1993 by Sartono, 1.4-0.9 million years old. The portion featuring the ramus is heavily damaged but the rest of the find seems undamaged. Details from the teeth have been lost. *Meganthropus* D is only slightly smaller and similar in shape to *Meganthropus* A. Sartono, Krantz and Tyler all agree that specimen A and D belong to the same species, which is in-need of further investigation.
* *Meganthropus* I/Sangiran 27: A nearly complete, yet crushed cranium described by Tyler within the limits of *Meganthropus* but outside the presumed range of *H. erectus*. This specimen has a notable double sagittal ridge, nearly meeting at the peak of the skull with an extremely thickened nuchal ridge.
* *Meganthropus* II/Sangiran 31: A skull fragment described by Sartono in 1982, with Tyler later stating the fossil exceeds *H. erectus*' size range. The skull itself is deeper, lower vaulted and wider than any other specimen. Sanigran 31 bears the same double saggital crest, having a cranial capacity of 800-1000cc. Since the 1993 AAPA meeting in-which Tyler reconstructed the skull, it has been accepted by most sources. Like the others, Sanigran 31 is heavily damaged, but little post facial damage makes the chance of error very small. Tyler's reconstruction depicts the double sagittal crest, with the temporal muscles stretching up to the parietal where they nearly meet. No *H. erectus* bear this trait. Because of this, Krantz's reconstruction as a massive *H. erectus* is not trustworthy.
* *Meganthropus* III: Appearing to be the posterior fragment of the cranium, measuring 7-10 centimeters long. In 1996, Tyler described the specimen, noting the occipital angle may have been 120°, which he notes would have been out of *H. erectus*' range. He also states the latter would have a more angled occiput. However, his interpretation was doubted due to authorities suspecting the remains were not of the hominid he thought it did.
* Longgupo "Wushan Man": The Wushan specimen was first discovered at Longgupo at Dragon Bone Slope in 1986 alongside animal fossils such as *Gigantopithecus*, *Sinomastodon*, *Nestoritherium*, *Equus yunnanensis* and *Ailuropoda microta*. Additional stone tools thought to be human were uncovered later, but were likely recent additions to a site that contains non-*Homo* hominids. It was first named *Homo erectus wushanensis* in 1991 before reclassifying it as a mystery pongine in 2009 likely referable to *Meganthropus*. Initially, it was thought to be an early *Homo habilis* and *Homo ergaster*-like *Homo erectus* subspecies that descended from *Homo erectus* and gave rise to Far Eastern *Homo erectus*, which swept west-to-east. However, it was initially drawn to criticism, with some stating the morphology is most similar to *Pongo*; some state it is identical to *Lufengpithecus* or an East Asian human that accidentally entered the deposit via flowing water. In 2009, Ciochon stated he had changed his mind, that his former idea of a *Homo erectus* subspecies (or the species in total) contemporaneous with *Gigantopithecus* was instead a pongine most likely belonging to *Meganthropus*.

## References

1. ↑ https://books.google.ca/books?id=440TmWXToLAC&dq=%22proanthropus%22&source=gbs\_navlinks\_s
2. ↑ https://www.nature.com/articles/459910a
3. ↑ 3.0 3.1 https://www.nature.com/articles/s41559-019-0860-z?proof=t
4. ↑ 4.0 4.1 4.2 4.3 https://en.wikipedia.org/wiki/Meganthropus
5. ↑ https://www.travelchinaguide.com/river/yangtze\_attraction/little\_gorge/longgupo.htm
6. ↑ https://www.reuters.com/article/us-panda-skull-idUSN1841336520070618
7. ↑ https://en.wikipedia.org/wiki/Ailuropoda\_microta
8. ↑ https://english.cas.cn/newsroom/archive/research\_archive/rp2012/201502/t20150217\_143674.shtml
9. ↑ https://en.wikipedia.org/wiki/Wushan\_Man
10. ↑ https://www.nature.com/articles/378275a0