Two new studies add further pieces to the jigsaw puzzle that is human evolution. One reports a potential extra member of the genus Homo. The other casts light on possible interbreeding between three human species in the Middle East.

jigsaw /ˈdʒɪɡ.sɑː/ n. 拼图游戏

例句：We spent all evening doing a 1,000-piece jigsaw.

evolution /ˌev.əˈluː.ʃən/ n. 进化；演变

例句：Darwin\'s theory of evolution

genus Homo n. 人属

interbreed /ˌɪ̬ɚˈbriːd/ v.（使）杂交繁殖

例句：Some of the wolves had interbred with domestic dogs.

Homo longi—“Dragon man” as translated into English from Chinese, via Latin—is not a novel find, but a reinterpretation of an existing one. The cranium in question was dug up in Harbin in 1933 and is held at Hebei Geo University, in Shijiazhuang. It is 146,000 years old and was originally badged as an archaic form of Homo sapiens. But Ni Xijun and Ji Qiang, who work at the university, disagree. As they report in the Innovation, the cranium would indeed have contained a brain similar in size to a modern human’s, but the fossil is too large to be sapiens and has molars and eye sockets which dwarf those of people today. Dr Ni and Dr Ji also realised that it is too long and low to be sapiens. It lacks the roundness of a modern human cranium.

novel /ˈnɑː.vəl/ adj. 新颖的，新奇的

例句：a novel idea/suggestion

cranium /ˈkreɪ.ni.əm/ n. 颅，头颅；头盖骨

badge /bædʒ/ v. 授予徽章

archaic /ɑːrˈkeɪ.ɪk/ adj. 古老的，原始的

例句：The system is archaic and unfair and needs changing.

Homo sapiens n. 智人

molar /ˈmoʊ.lɚ/ n. 臼齿，磨牙

dwarf /dwɔːrfm/ v. 使…相形见绌；使…显得矮小

例句：The new skyscraper will dwarf all those near it.

This is good news for supporters of the recent­African­origin theory, which holds that most non­African human beings alive today are descendants of a small number of migrants who crossed to Asia from the Horn of Africa about 60,000 years ago, meaning that any non­African human fossil from before that date is probably of another species descended from earlier, nonsapiens departures from Africa.

descendant /dɪˈənt/ n. 子孙，后代

例句：He has no descendants.

fossil /ˈfɑː.səl/ n. 化石

The question was, which earlier species did the Harbin fossil represent? By comparing it with known archaic humans, including  Homo erectus,  Homo floresiensis, Homo heidelbergensis and  Homo neanderthalensis, Dr Ni and Dr Ji concluded that it was none of them, and must therefore be new to science and so worthy of its own name. There is, however, one other possibility—for there is a now­extinct type of human of which no cranium has yet been identified.

extinct /ɪkˈstɪŋkt/ adj. 灭绝的；绝种的；消失的

例句：There is concern that the giant panda will soon become extinct.

Homo denisova’s existence was established by the extraction of DNA from a finger bone, and traces of that DNA, a remnant of interspecies breeding, still exist in modern humans, notably in China. Since one of the Harbin fossil’s molars perfectly matches the size and root structure of a molar from the Denisova cave in Russia, after which Homo denisova is named, it may be that Dr Ni and Dr Ji have actually identified the first Denisovan cranium.

trace /treɪs/ n. 痕迹，踪迹

例句：He attempted to cover up all the traces of his crime.

remnant /ˈənt/ n. 残余（部分）；剩余（部分）；零头；零料

例句：the remnants of last night\'s meal

The other study, published in Science by Israel Hershkovitz of Tel Aviv University, also speaks to the question of interspecific interbreeding. Even supporters of the recent­African­origin theory recognise that there was, in addition, an earlier “leakage” of Homo sapiens from north­east Africa into the Levant. Dr Hershkovitz and his colleagues have been examining fossils of relevant antiquity—120,000­140,000 years—collected from Nesher Ramla, a site in Israel. These, they found, have sapiens­like jaw bones, Neanderthal­like molars and crania similar to those of Homo erectus. This suggests to them that they are the product of miscegenation between all three.

interspecific /ɪnˈtɝː spəˈsɪf.ɪk/

adj. 【生物学】(异)种间的

leakage /ˈliː.kɪdʒ/ n. 泄漏；渗漏

例句：The leakage was traced to an oil pipe in the cellar.

antiquity /ænˈtɪə.t̬i/ n. （尤指六世纪以前的）古代

例句：Cannabis has been used for medicinal purposes since antiquity.

miscegenation /ˌmɪsɪdʒəˈneɪʃn/ n. 种族混合

That so much interbreeding went on between groups of people who had evolved separately for hundreds of thousands of years is intriguing. Besides the imprint of Denisovan genes in modern Asians, it is also known that modern Europeans bear traces of Neanderthals and that some modern Africans similarly bear the imprint of a “ghost” hominid for which no fossil evidence has yet been found. The ancestry of Homo sapiens, it seems, is less a family tree than a worldwide web.

intriguing /ɪnˈtriːɡɪŋ/ adj. 有趣的；迷人的

例句：This intriguing book is both thoughtful and informative.

imprint /ɪmˈprɪnt/ n. 印记；痕迹；特征；版本说明

例句：She could see the imprint of her fingers on his pale face.

hominid /ˈhɑːmɪnɪd/ n. 原始人类；人科动物