Last updated on April 17, 2014 at 1:21 EDT

Homo floresiensis

Homo floresiensis

Homo floresiensis, or Flores Man, nicknamed “hobbit” and “Flow”, is an extinct species in the genus Homo. The remains of an individual that would have stood about 3 feet in height were uncovered in 2003 on the island of Flores in Indonesia. Incomplete skeletons of nine individuals have been recovered, including one complete cranium. These remains have been the focus of intense research to establish whether they represent a species distinctive from modern humans. This hominin is extraordinary for its small body and brain and for its survival until comparatively recent times. Stone tools from archaeological horizons ranging from 94,000 and 13,000 years ago. It’s thought by some that this creature might be at the source of the Ebu gogo myths prevalent on the isle of Flores.

Archaeologist Mike Morwood and colleagues, who discovered the fossils, suggested that a variety of features, both derived and primitive, identify these individuals as belonging to a new species, H. floresiensis, within the taxonomic tribe of Hominini. Currently, Hominini consists of the extant species Homo sapiens, bonobo, and chimpanzee; their ancestors; and the extinct lineages of their common ancestor. The discoverer also proposed that H. floresiensis lived synchronously with modern humans on Flores.

Two orthopedic researchers published in 2007 reported evidence to sustain species status for H. floresiensis. A study of three tokens of carpal bones came to conclusion that there were similarities to the carpal bones of a chimpanzee or an early hominin such as Australopithecus and also differences from the bones belonging to modern humans. A study of the bones and joints of the arm, shoulder, and lower limbs also came to the conclusion that H. floresiensis was more similar to early humans and apes than the modern humans. In 2009, the publication of a cladistic analysis and a study of proportional body measurements supply additional support for the hypothesis that H. floresiensis and H. sapiens are separate species.

The specimens were uncovered on the Indonesian island of Flores in the year 2003 by a joint Australian-Indonesian team of archaeologists seeking evidence of the original human migration of H. sapiens from Asia to Australia. They weren’t anticipating to find a new species, and were surprised at the retrieval of a nearly whole skeleton of a hominin they christened LB1 due to it unearthing inside the Liang Bua Cave. Following excavations recovered seven more additional skeletons, dating from 38,000 to 13,000 years ago. An arm bone temporarily assigned to H. floresiensis is about 74,000 years old. The specimens aren’t fossilized and have been described as having “the consistency of wet blotting paper”; once exposed, the bones had to be left out to dry before they could be dug up.

Sophisticated stone implements of a size considered suitable to the 3 feet tall human are also extensively present in the cave. The implements are at horizons from 95,000 to 13,000 years ago and are linked with an elephant of the extinct genus Stegodon, most likely the prey of LB1. They also shred the island with giant rats, Komodo dragons, and even bigger species of lizards. H. sapiens reached the area by around 45,000 years ago.

H. floresiensis was revealed on October 28 of 2004, and was quickly nicknamed “Hobbit”, after the fictional race popularized in J. R. R. Tolkiens book The Hobbit, and a suggested scientific name for the species was Homo hobbitus. It was originally placed in its own genus, Sundanthropus floresianus, but reviewers of the article felt that the cranium, in spite of its size, belonged in the genus Homo.

The most important and noticeable identifying features of H. floresiensis are its small body and small cranial capacity. Brown and Morwood also identified numerous additional and less obvious features that might distinguish LB1 from modern H. sapiens, including the form of the teeth, the absence of a chin, and the lesser angle in the head of the humerus. Each of these alleged distinguishing features has been heavily examined by the scientific community, with different research groups reaching differing assumptions as to whether these features support the original designation of a new species, or whether they identify LB1 as a severely pathological H. sapiens.

The discovery of additional incomplete skeletons has confirmed the existence of some features found in LB1, such as the lack of a chin, but Jacob and other research teams argue that these features don’t set apart LB1 from local H. sapiens morphology. Lyras et al. have declared, based on 3D-morphometrics, that the skull belonging to LB1 differs greatly from all H. sapiens skulls, including those of small-bodied individuals and microcephalics, and is a lot like the skull of H. erectus alone.

LB1’s height has been estimated at about 3 feet 6 inches. The height of a second skeleton, LB8, has been estimated at 3 feet 7 inches based on measurements of its tibia. These estimations are outside the range of usual modern human height and significantly shorter than the average adult height of even the smallest modern humans, such as the Mbenga and Mbuti.

Aside from a smaller body size, the specimens appear otherwise to resemble H. erectus, a species known to have been living in Southeast Asia at times concurrent with other finds allegedly to be of H. floresiensis. These detected similarities form the basis for the suggested phylogenetic relationship. Controversially, the same team has reported finding material evidence such as stone tools of one Flores of a H. erectus occupation dating back 840,000 years ago, but not remains of H. erectus itself or transitional forms.

To explain the small build of H. floresiensis, Brown et al. have proposed that the limited food environment on Flores, H. erectus evolved a smaller body size by means of insular dwarfism, a form of speciation which has been observed in other species on Flores as well.

In addition to a small body size, H. floresiensis had an extraordinarily small brain. The brain of the holotype LB1 estimated to have had a volume of 426 cubic centimeters, placing it at the range of chimpanzees or the extinct australopithecines. LB1’s brain is half that of its presumed direct ancestor H. erectus.

The species is thought to have survived on Flores at least until 12,000 years before the present, making it the longest lasting non-modern human, surviving long past the Neanderthals, which became extinct about 24,000 years ago. Due to a deep neighboring strait, Flores remained secluded during the Wisconsin glaciation, in spite of the low sea levels that united Sundaland. This has led the discoverers of H. floresiensis to come to the conclusion that the species, or its ancestors, could only have reached the isolated island via water transport, perhaps arriving on bamboo rafts around 100,000 years ago. At this time, the islands of Komodo and Flores were joined, leaving a 12 mile wide strait to be crossed with Komodo visible from the mainland. This idea of H. floresiensis utilizing advanced technology and collaboration on a modern human level has encouraged the discoverers to hypothesize that H. floresiensis almost definitely had language.

Image Caption: Homo floresiensis (the “Hobbit”). Credit: Ryan Somma/Wikipedia (CC BY-SA 2.0)

Homo floresiensis