SciPak

古代マヤ文明には複数の集団との文化交流があった

マヤ文明の起源に関してはこれまでに、2つの優勢な説があった。1つは現在のメキシコ南部、グアテマラ、ベリーズにあたる地域でほぼ独自に発展したという説。もう1つはマヤ文明より古いオルメカ文明の文化的影響を大きく受けたという説である。今回、ともにアリゾナ大学（米国、ツーソン）の研究者であるTakeshi Inomata（猪俣健）、Daniela Triadan夫妻が率いる米国や日本の研究者から成る発掘調査チームは、これらの2説ではマヤ文明の起源を十分に説明できないことを明らかにした。セイバルの広場群やピラミッド群と、グアテマラの古代マヤ遺跡はおそらく、紀元前約1,000年～700年に南部メソアメリカで起こっていた広範な文化的交流から生じたと彼らは提唱している。

（Science 4月26日号に掲載）

[Reconstruction: Daniela Triadan; Photo: Takeshi Inomata. Click for caption information.]

Anyone wishing to use the cover of Science must contact AAAS to request permission to do so.

Ancient Maya Swapped Culture With Multiple Groups

Until now, two theories have dominated the debate concerning the origin of the Maya civilization: one suggesting that the Maya developed almost entirely on their own in what is now southern Mexico, Guatemala, and Belize, and another suggesting that the older Olmec civilization was the Maya’s dominant cultural influence. Takeshi Inomata and Daniela Triadan, a husband-and-wife team from the University of Arizona in Tucson, along with colleagues from the U.S. and Japan, however, found that neither of these theories could tell the full story of the Maya. According to the researchers, the plazas and pyramids at Ceibal, an ancient Maya site in Guatemala, probably arose from broad cultural exchanges that took place across southern Mesoamerica from about 1,000 to 700 BCE.

This research appeared in the 26 April issue of Science.

[Reconstruction: Daniela Triadan; Photo: Takeshi Inomata. Click for caption information.]

Anyone wishing to use the cover of Science must contact AAAS to request permission to do so.

Human Evolution Takes a Twist With Australopithecus sediba

A set of six research reports, accompanied by an introductory essay in the 12 April issue of Science serve up a complete view of the anatomy and likely habits of Australopithecus sediba, the 2-million-year-old fossil remains of several partial skeletons found in 2008 at the site of Malapa, near Johannesburg, South Africa. The studies show that Au. sediba is a mosaic of human and ape-like traits, with a human-like pelvis, hands and teeth, and a chimpanzee-like foot. Researchers still aren’t sure where Au. sediba fits into the hominin family tree, but these six studies show that the Malapa fossils are a striking example of human evolution.

Read more here and here.

[Reconstruction by Peter Schmid, Photo by Lee R. Berger. Image courtesy of Lee R. Berger and the University of the Witwatersrand. Click the image for more information.]

Older Origins for Spear-Making Technology

Early humans were lashing stone tips to wooden handles to make spears and knives about 200,000 years earlier than previously thought, new research suggests. “Hafting” was an important technological advance that made it possible to handle or throw sharp points with much more power and control. Both Neandertals and early Homo sapiens made hafted spear tips, and evidence of this technology is relatively common after about 200,000 to 300,000 years ago. Jayne Wilkins and colleagues now present multiple lines of evidence implying that stone points from the site of Kathu Pan 1 in South Africa were hafted to form spears around 500,000 years ago.

Read more about this research from the 16 November issue of Science here.

[Image courtesy of Jayne Wilkins; click the image for more information.]

Bipedal Human Ancestor Spent Time in the Trees

After analyzing the fossilized shoulder bones of a juvenile Australopithecus afarensis called Selam, or DIK-1-1, researchers in Science suggest that these early human ancestors, although bipedal, were also very active climbers. This slideshow from the AAAS Office of Public Programs highlights these new findings from the report by David Green and Zeresenay Alemseged titled, “Australopithecus afarensis Scapular Ontogeny and Function, and the Role of Climbing in Human Evolution.”

Click the image to watch a slideshow of images about the research. Read more about this research from the 26 October issue of Science here.

How Local Institutions Tamed Warfare in Papua New Guinea

It’s been argued recently that humans have become less violent as modern-day cultural institutions and governments have evolved. But, at least some small-scale societies have their own customary institutions that can quell runaway warfare, as a new study of the Enga of Papua New Guinea shows. Whereas many studies of violence rely heavily on models, Polly Wiessner at the University of Utah and Nitze Pupu at Enga Take Anda in Papua New Guinea gathered data from precolonial warfare, 501 recent wars and 129 customary court sessions to analyze an unusual natural experiment.

Read more about this research from the 28 September issue of Science here.

[Click the image for more information. Image courtesy of Polly Wiessner]

Sub-Saharan Genomes Shed Light on Human Origins

A new study of human genetic variation in sub-Saharan Africa, where modern Homo sapiens are believed to have originated, helps to reveal the region’s rich genetic history. Carina Schlebusch at Uppsala University and colleagues examined genetic variants of 220 individuals from 11 different populations across southern Africa to explore their relationships and commonalities. But, instead of honing in on a geographic location from which modern humans arose, the researchers discovered a complex record of admixture and stratification among these sub-Saharan populations.

Read more about this research from the 20 September issue of Science Express here.

[Image courtesy of Dr. Carina Schlebusch; click the image for more information.]

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The Source of Indo-European Languages

Indo-European languages first emerged in modern-day Turkey, and spread through the world along with agriculture, a new study suggests. The findings support one of two hotly debated scenarios for the origins of this language family. In this podcast, Dr. Quentin Atkinson discusses the research.

Read more about this research from the 24 August issue of Science here.

Fossils Suggest That Clovis Wasn’t Alone

New findings from the Paisley Caves in Oregon suggest that a stone tool technology known as Western Stemmed projectile points overlapped with—rather than followed—the technology of the Clovis culture. The Clovis, defined by their distinctive broad, fluted projectile points, probably arrived in North America about 13,500 years ago, and many researchers had believed that Western Stemmed projectile points evolved directly from Clovis technology. But these new findings, in the context of other fossils recovered from the caves, imply that a separate human population with their own unique technology may have occupied the far western region of what is now the United States while the Clovis culture developed on the Plains and in the Southeast.

Read more about this research from the 13 July issue of Science here.

[Photo by Jim Barlow. Click the image for more information.]

Cave Find Pushes Back Dates of Early Pottery

Pottery fragments from a cave in China are roughly 20,000 years old, which is about 2,000 years older than other known pottery remains, researchers at Peking University in Beijing, China report. Pottery was an important human invention; ceramic containers can hold food more securely than baskets or hide pouches, and they can be used in cooking. The earliest pottery has been thought to come from China and Japan, about 18,000 years ago.

Read more about this research research from the 29 June issue of Science here.

[Image: This is a pottery fragment from Xianrendong, west section 2A. Image courtesy of Science/AAAS.]