December 23, 2024

Meet Homo juluensis: a potential new human species

Meet Homo Juluensis: A Potential New Human Species
Illustration by Midjourney.

Today, there is only one hominid left roaming the world: our species, Homo sapiens. At, one point, however, we shared this planet with several other hominin species, including Neanderthals (Homo neanderthalensis), Homo floresiensis (also known as the “Hobbits”), Homo luzonensis, Homo naledi, and the long-lived Homo erectus. Now, a new study may add a new member to this roster: a species distinct from anything previously known, called Homo juluensis.

The story of Homo juluensis began in the 1970s when archaeologists discovered cranial and dental remains in Xujiayao, northern China. Initially, these fossils — dated to 200,000–160,000 years ago, and featuring a mosaic of human traits — were considered part of the broader human evolutionary puzzle but were not classified into a unique species. Decades later, a detailed analysis led by Christopher Bae from the University of Hawaiʻi and Xiujie Wu from the Chinese Academy of Sciences puts forth arguments for a re-classification as a distinct, novel human species.

Rediscovering Ancient Humans

Meet Homo Juluensis: A Potential New Human Species
Homo juluensis (blue five-pointed stars) includes Xujiayao, Xuchang, Xiahe, Penghu, Denisova, and Tam Ngu Hao 2; Homo longi (white triangles) includes Harbin, Dali, and Jinniushan; Homo floresiensis (pink diamond) includes Liang Bua; Homo luzonensis (green circle) includes Callao. Credit: Nature Communications.

More than 300,000 years ago, on the sprawling plains and forests of East Asia, Homo juluensis hunted wild horses and likely crafted stone tools. They lived in small, tight-knit groups, eking out a life in a challenging environment. Some evidence even suggests they processed animal hides — a resourceful adaptation for survival.

However, they vanished by around 50,000 years ago, leaving only tantalizing clues behind. Among these are fossilized jaws and teeth scattered across China, Korea, Japan, and Southeast Asia. Yet, these remnants resisted easy classification — until now.

“This study clarifies a hominin fossil record that has tended to include anything that cannot easily be assigned to Homo erectus, Homo neanderthalensis, or Homo sapiens,” said Bae. “Although we started this project several years ago, we did not expect being able to propose a new hominin species.”

The findings hinge on a strict and careful reorganization of fossils, akin to piecing together a fragmented family photo album. By comparing specimens from multiple sites, Bae and his team unearthed patterns pointing to the distinct characteristics of Homo juluensis.

Perhaps the most tantalizing aspect of this discovery is its potential connection to the Denisovans. These people have always been an enigma, first identified through DNA extracted from a finger bone discovered in Denisova Cave in Siberia in 2010. While their physical remains are sparse — comprising a few teeth, a finger bone, and fragments of a skull — genetic evidence shows they are distinct from any other hominids. According to the same genetic data, Denisovans shared a common ancestor with Neanderthals and split from them around 400,000 to 500,000 years ago. They occupied a vast range across Asia, interacting and interbreeding with early Homo sapiens.

The new study makes the bold claim that fossils from Xujiayao and Xuchang in northern China, alongside those from Denisova Cave and the Xiahe jawbone, may represent Homo juluensis. In other words, the Denisovans and Homo juluensis were one and the same. This grouping is based on shared morphological traits, particularly dentognathic (dental and jaw) characteristics.

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Besides dentognathic morphology, the Xujiayao fossils, in particular, reveal cranial features that are a mosaic of archaic and modern traits. For example, while they exhibit a large cranial capacity similar to Neanderthals, their skull shape differs in subtle ways, such as the proportions of the braincase and the presence of distinct brow ridges.

Yet, the hypothesis requires more evidence to solidify. DNA testing on Homo juluensis fossils could confirm whether Denisovans belong within this species or if they represent a distinct lineage.

The human story is far from simple. For decades, Asia’s fossil record has been a puzzle missing key pieces. Homo juluensis not only fills some of those gaps but also offers a clearer framework for organizing these ancient findings.

The findings were reported in the journal Nature Communications.