Lomekwian Stone Age: Stone Tools Predate The Genus Homo by 800 Thousand Years

3.3-million-year-old stone tools from Lomekwi 3, West Turkana, Kenya

Authors:

Harmand et al

Abstract:

Human evolutionary scholars have long supposed that the earliest stone tools were made by the genus Homo and that this technological development was directly linked to climate change and the spread of savannah grasslands. New fieldwork in West Turkana, Kenya, has identified evidence of much earlier hominin technological behaviour. We report the discovery of Lomekwi 3, a 3.3-million-year-old archaeological site where in situ stone artefacts occur in spatiotemporal association with Pliocene hominin fossils in a wooded palaeoenvironment. The Lomekwi 3 knappers, with a developing understanding of stone’s fracture properties, combined core reduction with battering activities. Given the implications of the Lomekwi 3 assemblage for models aiming to converge environmental change, hominin evolution and technological origins, we propose for it the name ‘Lomekwian’, which predates the Oldowan by 700,000 years and marks a new beginning to the known archaeological record.

Complicating Human Evolution: Is Little Foot as old as Lucy?

New cosmogenic burial ages for Sterkfontein Member 2 Australopithecus and Member 5 Oldowan

Authors:

Granger et al

Abstract:

The cave infills at Sterkfontein contain one of the richest assemblages of Australopithecus fossils in the world, including the nearly complete skeleton StW 573 (‘Little Foot’) in its lower section, as well as early stone tools in higher sections. However, the chronology of the site remains controversial owing to the complex history of cave infilling. Much of the existing chronology based on uranium–lead dating and palaeomagnetic stratigraphy has recently been called into question by the recognition that dated flowstones fill cavities formed within previously cemented breccias and therefore do not form a stratigraphic sequence Earlier dating with cosmogenic nuclides suffered a high degree of uncertainty and has been questioned on grounds of sediment reworking . Here we use isochron burial dating with cosmogenic aluminium-26 and beryllium-10 to show that the breccia containing StW 573 did not undergo significant reworking, and that it was deposited 3.67 ± 0.16 million years ago, far earlier than the 2.2 million year flowstones found within it. The skeleton is thus coeval with early Australopithecus afarensis in eastern Africa. We also date the earliest stone tools at Sterkfontein to 2.18 ± 0.21 million years ago, placing them in the Oldowan at a time similar to that found elsewhere in South Africa at Swartkans and Wonderwerk.

This would have gone up yesterday, but April 1st...

Llallawavis scagliai: a new Mesembriornithinae Terror Bird From Pliocene Neogene Argentina had Good Eyesight, but not as Good Hearing

A new Mesembriornithinae (Aves, Phorusrhacidae) provides new insights into the phylogeny and sensory capabilities of terror birds

Authors:

Degrange et al

Abstract:

Terror birds constitute the most outstanding group of the South American Cenozoic avifauna. Considered as apex predators, their hunting skills have recently been examined, but their diversity is still unresolved. Here we report a new terror bird from the late Pliocene of Argentina, represented by the most complete articulated skeleton of one yet found. Our phylogenetic analysis places this taxon among derived phorusrhacids (Mesembriornithinae). One of the most striking cranial features of the new species is the suppression of intracranial kinesis due to the presence of an independent ossified bone that increases the structural link between the lacrimal and jugal bars, and the absence of both palatal hinges. The new species possesses ossified tracheal rings and a tracheobronchial syrinx, as well as sclerotic ossicles to adjust the shape of the cornea during its diurnal vision, and reveals a mean hearing sensitivity (~2300 Hz) below the average for living species. The discovery of this new species provides new insights for studying the anatomy and phylogeny of phorusrhacids and a better understanding of this group's diversification.

Lower Jaw Fossil Pushes Earliest Example of Genus Homo to Piacenzian Pliocene Neogene

A fossil lower jaw found in the Ledi-Geraru research area, Afar Regional State, Ethiopia, pushes back evidence for the human genus -- Homo -- to 2.8 million years ago, according to a pair of reports published March 4 in the online version of the journal Science. The jaw predates the previously known fossils of the Homo lineage by approximately 400,000 years. It was discovered in 2013 by an international team led by Arizona State University scientists Kaye E. Reed, Christopher J. Campisano and J Ramón Arrowsmith, and Brian A. Villmoare of the University of Nevada, Las Vegas.

For decades, scientists have been searching for African fossils documenting the earliest phases of the Homo lineage, but specimens recovered from the critical time interval between 3 and 2.5 million years ago have been frustratingly few and often poorly preserved. As a result, there has been little agreement on the time of origin of the lineage that ultimately gave rise to modern humans. At 2.8 million years, the new Ledi-Geraru fossil provides clues to changes in the jaw and teeth in Homo only 200,000 years after the last known occurrence of Australopithecus afarensis ("Lucy") from the nearby Ethiopian site of Hadar.

Found by team member and ASU graduate student Chalachew Seyoum, the Ledi-Geraru fossil preserves the left side of the lower jaw, or mandible, along with five teeth. The fossil analysis, led by Villmoare and William H. Kimbel, director of ASU's Institute of Human Origins, revealed advanced features, for example, slim molars, symmetrical premolars and an evenly proportioned jaw, that distinguish early species on the Homo lineage, such as Homo habilis at 2 million years ago, from the more apelike early Australopithecus. But the primitive, sloping chin links the Ledi-Geraru jaw to a Lucy-like ancestor.

"In spite of a lot of searching, fossils on the Homo lineage older than 2 million years ago are very rare," says Villmoare. "To have a glimpse of the very earliest phase of our lineage's evolution is particularly exciting."

link.