工藤 雄一郎

Little is known about the spatiotemporal dynamics of gray wolves in the Pleistocene across low-latitude regions of Eurasia. In Japan, a small-bodied endemic subspecies of Japanese wolves existed and went extinct in the early 1900s. The fossil record indicates that a giant wolf, which reached 70 cm in body height, inhabited Japan during the Pleistocene, but its evolutionary relationship, if any, with the Japanese wolf remains uncertain. Here, to reveal the genetic origin of the Japanese wolf, we analyzed ancient DNA from remains (recovered in Japan) of one Pleistocene wolf that lived 35,000 years ago and one Holocene wolf from 5,000 years ago. The analysis of the mitochondrial DNA revealed that the Pleistocene wolf was not part of the Japanese wolf clade but rather an earlier-diverging lineage. The analysis of the nuclear DNA of the Holocene Japanese wolf revealed that it was an admixture of the Japanese Pleistocene wolf and continental wolf lineages. These findings suggest that the Japanese wolf originated via waves of colonization of multiple Pleistocene wolf populations at 57-35 and 37-14 ka, respectively, followed by interpopulation hybridization.

Here we describe a few cheek teeth and mandibular remains of a Pleistocene rhinocerotid from the Matsugae Cave in Kitakyushu City, Fukuoka Prefecture, western Japan. Previously, these remains had been identified as Dicerorhinus cf. nipponicus or Dicerorhinus sp. The present study redescribes and identifies them as belonging to Stephanorhinus sp. indet., like several other Japanese middle Pleistocene rhinocerotid remains. The present and other studies suggest that this genus reached Far East Asia during the middle Pleistocene. Stephanorhinus sp. from the Matsugae Cave would have migrated from northern China in 0.43 Ma as a member of the group of terrestrial mammals found in the cave.

Paleovegetation and climatic conditions in the Last Glacial Maximum (LGM; ca. 24.4 and 20.1 ka) were reconstructed based on plant macrofossils and pollen assemblages deposited in a sandy channel out-cropped in the Hanamuro River, Ibaraki Prefecture, central Japan. The plant macrofossil assemblages were composed of 31 arboreal and 76 herbaceous taxa. Occurrence of plants with various habitat preferences exhibited distribution patterns of highly diverse vegetation types depending on geo-morphology and humidity in and around the drainage of the Hanamuro River. Rich aquatic and wetland flora indicates an expansion of backmarsh mosaic environments along the river channel in the bottom of the valley. Wetland forests composed of Picea sect. Picea assignable to Picea koyamae, and riparian forests dominated by Alnus inokumae, are well represented in the macrofossil assemblages. Pinaceous conifers were dominant in mesic or dry places with Betula and the other deciduous broadleaved trees. Macrofossils and pollen indicates that Abies veitchii was distributed in mesic locations, Larix kaempferi and Picea jezoensis var. hondoensis were on the upper slopes, and Pinus koraiensis was dominant on the plateau. Dominant Selaginella remotifolia and the other drought-intolerant understory herbs indicate closed canopy of mesic coniferous forests, while many kinds of meadow and/or ruderal plants were indicative of open vegetation along the river and slopes. Annual mean temperature of the fossil site based on occurrence of Selaginella remotifolia was 8.1 degrees C, which is observed in present cool temperate zones where deciduous broad-leaved trees are dominant. This indicates that the distribution limit of subarctic conifers shifted to warmer temperature conditions than at present. The overlapping distribution of temperate and subarctic plants occurred widely in the lowlands in the distribution ranges of temperate trees, south of around 38 degrees N in Japan. In the LGM, with lower precipitation, dryness was an important environmental factor that controlled plant distribution along with temperature. Water stress confined temperate broadleaved trees to the humid valley bottoms and relieved conifers from competition against broad-leaved trees to promote their expansion to warmer regions. Macrofossils indicate the persistence of temperate plants in humid inland and/or northern refugia during the LGM, locations conducive to Paleolithic human occupation. (C) 2016 Elsevier Ltd and INQUA. All rights reserved.

In Japan plant remains excavated from lowland sites have revealed that people managed and used plant resources, especially arboreal ones, around settlements since the early Jomon period starting at ca. 7000 cal yr BP. This management of arboreal resources mainly consisted of management and use of native Castanea crenata (chestnut) and introduced Toxicodendron vernicifluum (lacquer tree) resources. At present this management system seems to have been established suddenly at the beginning of the early Jomon period. This is partly due to the paucity of sites of the preceding incipient and initial Jomon periods that yielded plant materials. Even in these periods, however, people must have used and did some kind of management of plant resources, because the management system appearing in the early Jomon period seems to be too sophisticated to appear suddenly and includes various introduced plants beside the lacquer tree. To clarify the human-plant relationship during the incipient and initial Jomon periods, we reviewed the studies on plant remains carried out in central to northeastern Japan. Based on the collected materials, we discussed change in the humaneplant relationship from the incipient and initial to the early Jomon periods from three points, change in the availability of Castanea crenata resources, change in people's mobility and sedentism, and submergence of sites in relation to the late Glacial to the early Holocene transgression. (C) 2016 Elsevier Ltd and INQUA. All rights reserved.

We have reconstructed landscape changes at a known obsidian source area in the central highland, Japan, using well dated pollen and micro-charcoal records, in order to better understand the difference in obsidian procurement between gathering in the Palaeolithic period (>30-16 ka cal BP) and mining in the Jomon period (16-2.9 ka cal BP). The pollen record at the site shows that alpine vegetation, such as patches of Pinus pumila (dwarf Siberian pine) and alpine meadows with rocky areas surrounded the area during the period 30-17 ka cal BP. The reconstructed Palaeolithic landscape implies that there was a favourable situation for gathering obsidian on the ground surface in the area. Subsequently, growth of woodland started at 17 ka cal BP due to a rise of the tree line elevation corresponding to the deglacial warming. The pollen record at the site shows that mixed woodland consisting of Betula (birch) and boreal conifers covered the area during the period 17-11.2 ka cal BP, and dense mixed oak woodlands flourished during the period 11.2-2.9 ka cal BP. From 17 ka cal BP, local conditions were unfavourable for gathering obsidian, and this probably caused the Jomon people to develop obsidian mining. We can suggest that the landscape changes between the Palaeolithic and Jomon periods strongly influenced the prehistoric exploitation of obsidian in the area.

宮崎県王子山遺跡から出土した縄文時代草創期の炭化植物遺体の¹⁴C年代測定，鹿児島県西多羅ヶ迫遺跡および上床城跡遺跡から出土した縄文時代草創期から早期初頭の土器付着炭化物の¹⁴C年代測定，炭素・窒素安定同位体分析を行ってその年代的位置づけを検討し，土器付着物については煮炊きの内容物の検討を行った。王子山遺跡の炭化コナラ属子葉と炭化鱗茎類は縄文時代草創期のものであることを確かめた。これらは縄文時代草創期の南九州において，コナラ亜属のドングリやユリ科ネギ属の鱗茎が食料として利用されていたことを示す重要な例である。一方，西多羅ヶ迫遺跡の無文土器は，隆帯文土器の直後の時期に位置づけられると推定され，鹿児島県建昌城跡から出土した無文土器の年代とも比較的近いものであった。ただし，炭素・窒素安定同位体分析の結果から，煮炊きの内容物に海産物が含まれている可能性も考えられるため，正確な年代的位置づけについては課題を残した。これらの無文土器は縄文時代早期初頭岩本式よりも，隆帯文土器の年代により近いことが分かったことは大きな成果である。上床城跡遺跡の水迫式～岩本式の土器は，これまでの縄文時代早期初頭の土器群の年代と良く一致している。縄文時代草創期から早期初頭の土器群や関連する遺構群，植物質遺物の¹⁴C年代測定例，土器付着炭化物の安定同位体分析例を蓄積していくなかで，隆帯文期の生業活動の解明，その後の消滅，縄文時代早期初頭の貝殻文系土器群の登場に至るプロセスとその実態を明らかにしていくことが重要である。This paper presents a chronological study of the charred plant remains of the Incipient Jomon period excavated at the Oujiyama site in Miyazaki Prefecture and the charred pottery adhesions from the Incipient Jomon period to the beginning of the Initial Jomon period excavated at the Nishitaragasako and Uwatoko Fortress sites in Kagoshima Prefecture. The former are analyzed by radiocarbon dating, while the latter are examined not only through radiocarbon dating but also through stable carbon/nitrogen isotope analysis to identify what was cooked in the pottery. The results confirmed that the charred plant remains of Quercus and bulb excavated at the Oujiyama site are dated to the Incipient Jomon period. This is important evidence to indicate that acorns of Quercus and bulbs of Allium (Liliaceae) were used as food in Southern Kyūshū in the Incipient Jomon period. Meanwhile, the mumon pottery (plain pottery) excavated at the Nishitaragasako site is assumed to immediately postdate ryūtaimon pottery (linear-relief pottery) and to be contemporary with the mumon pottery excavated at the Kenshō Castle site in Kagoshima Prefecture although their dates cannot be identified precisely because the results of stable carbon/nitrogen analyses suggest that the pottery adhesions may include seafood. It is, however, worth noting that the mumon pottery is chronologically placed right after ryūtaimon pottery in the Incipient Jomon period and before Iwamoto-type pottery in the beginning of the Initial Jomon period. The dates of Iwamoto-type pottery excavated at the Uwatoko Fortress site match those of pottery dated to the beginning of the Initial Jomon period. It will be important to reveal people's livelihood in the ryūtaimon period and the actual transition process from the demise of ryūtaimon pottery to the emergence of kaigaramon-type pottery (shell-impressed pottery) by accumulating data of radiocarbon dating results of plant remains, pottery and relevant structural remains and the stable isotope analyses of charred pottery deposits.

2009年12月に較正曲線IntCal09が公開され，日本列島の後期旧石器時代初頭から縄文時代草創期まで，IntCalを用いて較正年代が議論できるようになった。しかしながら，すでにIntCal04で公開されていた26,000～12,000cal BPの範囲でも大きな変更が加えられており，特に土器出現期の年代域での差が著しい。IntCal09の場合，土器出現期の前後の年代域ではカリアコの海底堆積物など多くのデータが加わり，より詳細な較正曲線となったが，較正曲線が平坦な「13,000年問題」の年代域に該当するため，この年代に該当する遺跡や土器群の較正年代を絞り込むのは極めて難しいことがわかった。現状では，日本列島における土器の出現を17,000～15,000cal BPの間のどこかの可能性が高いと指摘するに留めておきたい。これに対し，IntCal09を用いてもIntCal04を用いても，隆起線文土器の年代が15,000cal BP以後が中心である点は，これまでの年代的位置づけとほとんど変わらないことがわかった。隆起線文土器に先行する土器群が，日本列島で最古段階の土器群であることは間違いないが，その中でも最古に位置づけられる土器が，列島内のどこで使用され始めたかによって，出現時の土器の用途と古環境との関係性の議論も異なってくる。土器の出現とその用途，出現の歴史的意義については単純に一般化できる問題ではなく，その後の土器の普及と古環境とのかかわりも含めて，今後詳細に議論していくことが必要である。The latest International Calibration curve "IntCal09" was released in December 2009. It enables us to examine the absolute age of archaeological sites situated in the Japanese archipelago spanning from the Early Upper Palaeolithic to the Incipient Jomon sub period (37,000 to 11,000 cal BP) . However, it has been noticed that besides the extension of the IntCal04 before 26,000 cal BP, there have been some changes in the IntCal09 calibration curve during 26,000 to 12,000 cal BP, the time span of which has already been released in the IntCal04. In addition, these changes are more than a little different between IntCal09 and IntCal04, especially in the time span of the earliest pottery ( about 17,000–15,000 cal BP) in the Japanese archipelago. In this time span, plenty of data for the calibration from the marine sediment from the Cariaco Basin have been added to the IntCal09 dataset; however, it becomes difficult to identify the absolute age of the earliest pottery because of the shape of the calibration curve, which falls under "the year 13,000 problem". On the contrary, the calibrated age of the Linierrelief pottery group seems to be placed after 15,000 cal BP. The calibrated age of the Linier-relief pottery estimated by the IntCal09 is not very different from that of IntCal04. There is no doubt that the pottery that precedes the Linier-relief pottery group has been placed into the earliest phase of the Incipient Jomon sub period. However, any interpretation of possible correspondence between the application of the earliest pottery and its paleoenvironmental background should vary according to the place where the earliest pottery had been used in the Japanese archipelago. The issues of the emergence of the earliest pottery, its application, and its historical significance should not have been generalized without careful consideration. Further consideration is a must for not only the emergence but also the popularization of the pottery and its relationships with the environment.

The pattern of latest Pleistocene climate changes reconstructed on the basis of sediment cores from Lake Nojiri is one of the most detailed and reliable reconstructions in Japan. The climate changes over the last 72 ka can be compared directly with those recorded at Upper Paleolithic and Incipient Jomon sites on the basis of a revised age model for the Lake Nojiri sediment cores and the revised C-14 dates, calibrated after IntCal09. Fossil bones of megafauna from the Tategahana site beside the lake have been placed ca. 53-37 ka cal BP, in the relatively warm, temperate climate of the early MIS 3. Part of the Tategahana site was interpreted as a kill and butchery site, although the presence of the "big game hunters" is still uncertain, as so far there is no reliable archaeological evidence in the Japanese archipelago dating back to the Middle Paleolithic. The number of Paleolithic sites increased suddenly after 38 ka cal BP around Lake Nojiri. This seems to coincide with the timing of the migration of Homo sapiens into the Japanese archipelago. The climate had been gradually cooling toward the last Glacial Maximum (LGM). However, the area around lake Nojiri in the late MIS 3 seems to have been a suitable place for the subsistence of hunter-gatherers. Backed blade industries (ca. 29-20 ka cal BP), point-tool industries (ca. 22-19 ka cal BP), and microblade industries (20-16 ka cal BP) were characteristic of the Late Upper Paleolithic. The number of sites around Lake Nojiri decreased significantly during the LGM. At the end of the LGM, an abrupt change of vegetation, from subarctic conifer forest to deciduous broadleaf forest, had occurred around 14 ka, and human activities became prominent around Lake Nojiri, as shown by the linear-relief pottery group (ca. 15-13 ka cal BP). The number of sites seems to have decreased slightly during the Younger Dyras cooling event. Patterns of human occupation around lake Nojiri show the influence of global and local climate changes. (C) 2011 Elsevier Ltd and INQUA. All rights reserved.

花室川中流域の更新世末期堆積物における14C 年代測定，花粉分析，木材化石の樹種同定から，最終氷期の環境変遷と絶滅種のヒメハリゲヤキの古生態的特徴を考察した。この地域では，約5.0 万年前以前〜4.3万年前には比較的に温暖な気候環境下で，カバノキ属やコナラ亜属を主とする冷温帝性落葉樹林が分布し，約3.8〜3.5 万年前には寒冷化に伴って，冷温帯性落葉樹と亜寒帯性針葉樹の混交林となった。約3.5〜1.7 万年前には寒冷な気候となり，森林はマツ属単維管束亜属やトウヒ属を主体とする亜寒帯性針葉樹林へと変化した。緩斜面や河床では，約5.0〜2 .4万年前にはハンノキやヤナギ属の湿地林が形成された。約2.5 万年前以降の谷底では泥炭地が形成され，カヤツリグサ科やヨモギ属などの草原が広がった。この地域では，ヒメハリゲヤキが少なくとも約5.0〜4.3万年前まで冷温帯の気候環境下で生育し，その後の最終氷期極相期における寒冷化が原因となって絶滅した。

東京都東村山市下宅部遺跡では，縄文時代中期から後・晩期の土器の内面に付着した炭化植物遺体（土器付着植物遺体）が40点見つかっている。これは，土器の内部に炭化して付着した鱗茎，繊維，種実，編組製品などの植物起源の遺物を総称したものである。いずれも二次的に付着したものではなく，調理や植物を加工する際に付着した植物であり，当時の人々が利用していた食材と土器を用いた調理方法を解明する大きな手がかりとなる資料である。本研究では，そのうちの26点の土器について¹⁴Ｃ年代測定，炭素・窒素安定同位体比分析，C/N比の分析を実施し，これらの土器付着植物遺体の年代的位置づけ，および内容物についての検討を行った。また，単独で出土し，所属時期が不明であった種実遺体５点の¹⁴Ｃ年代測定を行い，年代的位置づけについて検討した。その結果，分析した土器付着植物遺体は縄文時代中期中葉の１点を除き縄文時代後・晩期に属する年代であり，特に3,300～2,700 cal BPの間に集中し，そのほとんどが縄文時代晩期前葉～中葉であることが判明した。種実遺体のうち，縄文時代中期中葉の約4,900 cal BPの年代を示したダイズ属炭化種子は，直接年代測定されたものとしては最も古い資料となった。土器付着植物遺体の炭素・窒素安定同位体比とC/N比を下宅部遺跡出土の精製土器付着物の分析結果や，石川県御経塚遺跡，大阪府三宅西遺跡出土の縄文時代後・晩期の土器付着炭化物の分析結果と比較してみると，下宅部遺跡の土器付着植物遺体は，陸上動物起源の有機物や海洋起源の有機物の混入の可能性が指摘されている土器付着炭化物とは分布傾向が明らかに異なり，Ｃ₃植物に特徴的な傾向を示した。特に，編組製品や繊維付着土器では，編組製品や繊維そのものと，それらと一緒に煮炊きした内容物の同位体比が異なることが明らかになった。今後，土器付着植物遺体の分析事例を増やし，縄文時代の植物利用や土器を用いた調理についての研究を展開していくことが必要である。

近年，縄文土器編年の放射性炭素年代に関する研究が著しく進展し，環境変化と人類活動の変化との時間対応関係について議論することが可能となりつつある．本研究では，完新世の約11,500～2,800 cal BPを対象として，これまでの研究で認められている関東平野の環境イベントと，環境変化を高精度で復元した近年の研究を比較した．そして，暫定的にではあるが約11,500，8,400，5,900，4,500，3,000 cal BPのイベント（IV～VIII）を設定し，段階（段階IV～段階VIII）を区分した．また，縄文時代早期初頭から晩期中葉までの各土器型式に関する放射性炭素年代を較正することで，各段階と考古学的編年とを対比した．その結果，段階IV（ca. 11,500～8,400 cal BP）は撚糸文土器群前半から野島式まで，段階V（ca. 8,400～5,900 cal BP）は鵜ヶ島台式から諸磯a式まで，段階VI（ca. 5,900～4,500 cal BP）は諸磯b式から加曽利E4式まで，段階VII（ca. 4,500～2,800 cal BP）は称名寺1式から安行3c式まで，段階VIII（ca. 2,800 cal BP以降）は安行3d式以降の諸型式と対比できることが明らかとなった．