著者

平野 弘道 利光 誠一 松本 崇 高橋 一晴

出版者

日本古生物学会

雑誌

化石 (ISSN:00229202)

巻号頁・発行日

vol.66, pp.47-49, 1999-09-10 (Released:2017-10-03)

参考文献数

13

被引用文献数

1

著者

栗原 憲一 川辺 文久

出版者

日本古生物学会

雑誌

化石 (ISSN:00229202)

巻号頁・発行日

vol.74, pp.36-47, 2003-09-20 (Released:2017-10-03)

参考文献数

47

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This paper documents extinction-recovery patterns of ammonoids and inoceramids across the Cenomanian/Turonian boundary (CTB) including the Oceanic Anoxic Event 2 (OAE2) in the Hakkin-zawa River section, Oyubari area, Hokkaido, Japan, and the Pueblo section, Western Interior, USA. The timing of extinction and recovery in these molluscan faunas occurred synchronously in both areas, based on micro-and macrofossil biostratigraphy and carbon-isotope chemostratigraphy. In the Hakkin-zawa, an ammonoid diversity decreased 0.5 to 0.9 m.y. prior to the CTB (extinction interval), reached a minimum just after the CTB (survival interval), and recovered 0.2 to 0.5 m.y. after the CTB (recovery interval). Inoceramids became increasingly dominant during the extinction and survival intervals, and the genus Inoceramus was replaced by the genus Mytiloides in the latter part of the survival interval. In the Western Interior, the extinction interval spanned 0.42 m.y. before the CTB, and the recovery of faunas took place after 0.15 m.y. from the CTB. In the Western Interior, nekto-benthic ammonoids of acanthoceratids disappeared earlier than planktonic heteromorph ammonoids such as Sciponoceras and Allocrioceras in the extinction interval. By contrast, the nektobenthic desmoceratids also appeared in the later part of the extinction interval in Hokkaido. This inconsistency presumably resulted from different expansion processes for oxygen-depleted water in an open ocean setting (Hokkaido) and a restricted seaway (Western Interior).

著者

早川 浩司

出版者

日本古生物学会

雑誌

化石 (ISSN:00229202)

巻号頁・発行日

vol.53, pp.48-49, 1992-11-30 (Released:2017-10-03)

著者

松本 達郎

出版者

日本古生物学会

雑誌

化石 (ISSN:00229202)

巻号頁・発行日

vol.33, pp.32, 1983-06-15 (Released:2017-10-03)

著者

横山 芳春 安藤 寿男 橋本 聡子

出版者

日本古生物学会

雑誌

化石 (ISSN:00229202)

巻号頁・発行日

vol.76, pp.32-45, 2004-09-22 (Released:2017-10-03)

被引用文献数

1

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Large oyster shell beds are contained in incised-valley fill deposits of the Cycle 1 of the Miwa Formation, Shimosa Group, Lake Kasumigaura area, Ibaraki Prefecture . This paper describes taphonomic processes of large oyster shell beds well exposed in three localities . Six shell bed types can be recognized on the basis of their lithology, sedimentary facies, mode of fossil occurrence and associated fossils : 1) autochthonous aggregated, 2) autochthonous scattered, 3) parautochthonous aggregated, 4) cross-bedded aggregated, 5) crossbedded scattered and 6) shell-fragment aggregated types. The large oyster shell bed higher than 5 m and wider than 30 m at east Hama (Loc. 1) is characterized by type 1 with two layers of type 3 five to 20 cm thick that seem to have formed by sudden storm events. The second shell bed at west Hama (Loc. 2) shows two mounds 3 m high and or wider than 7-10 m composed of type 1 and covered by massive muddy sediments. This means that the oyster banks were buried under estuary mud. The last example at Sakihama (Loc.3) is the largest oyster shell bed in this area with height of 5m and width of 70m. It can be divided into three unit bounded by two erosional surfaces. The unit I is composed mainly of type 1 representing in situ oyster reefs, and subordinately of 3 formed by reworking through tidal current. The unit II composed of types 4 and 5 forms a shallow channelfilled structure that seems to have been formed as a tidal channel. The overlying unit III above a flat erosional surface mostly consists of type 6. Reworked oyster shell fragments might have concentrated intermittently and condensed through muddy sediment bypassing within tidal flat to embayment.

著者

小林 貞一

出版者

日本古生物学会

雑誌

化石 (ISSN:00229202)

巻号頁・発行日

vol.47, pp.39-46, 1989-12-05 (Released:2017-10-03)

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This is an illustration of "Palaeontology and Historical Geology" as two related sciences. The article comprises three chapters on (1) What is Historical Geology?, (2) the Geological Age and the transformation of the biosphere through the age, and (3) the Object and Research Method of Historical Geology.

著者

昆 健志 井上 潤

出版者

日本古生物学会

雑誌

化石 (ISSN:00229202)

巻号頁・発行日

vol.106, pp.5-17, 2019

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Understanding the process by which life diversifies is one of the central issues in biology. To clarify this process in focal taxa as well as to conduct phylogenetic analyses, a divergence time estimation —an important analysis to determine the timescale of a phylogenetic tree— must be performed. It is thought that the diversification process can be vividly reconstructed by estimating the diversification rate and ancestral geographic area, characterizing ancestral ecology, and mapping ancestral habitats according to a time-calibrated phylogenetic framework. Here we introduce a divergence time estimation method and various other methods for reconstructing the process of diversification based on the time-calibrated phylogenetic framework with some study examples of aquatic organisms, mainly fish.

著者

増田 孝一郎

出版者

日本古生物学会

雑誌

化石 (ISSN:00229202)

巻号頁・発行日

vol.31, pp.47-49, 1982-06-21 (Released:2017-10-02)

著者

矢島 道子

出版者

日本古生物学会

雑誌

化石

巻号頁・発行日

vol.77, 2005

著者

江木 直子 荻野 慎諧 高井 正成

出版者

日本古生物学会

雑誌

化石 (ISSN:00229202)

巻号頁・発行日

vol.104, pp.21-33, 2018-09-30 (Released:2019-04-03)

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We report occurrences of carnivorans from the Irrawaddy beds in central Myanmar. Intensive expeditions in the recent decade improved understandings on biostratigraphic position of each fauna within the Irrawaddy beds (Late Miocene to Early Pleistocene) and brought out discovery of carnivoran specimens. An amphicyonid has been collected from the Tebingan locality, near the basal horizon (Late Miocene) of the Irrawaddy beds. This large animal is considered to be a new genus endemic to Myanmar. The Chaingzauk fauna (around the Miocene/Pliocene boundary) yields the most abundant remains: An ailurid (Simocyon), a large ursid (Agriotherium), a saber-tooth felid (Homotherium), at least three species of hyaenids including a primitive subfamily member (Ictitherium), a running form (Hyaenictis), and a wolf-like form (Hyaenictitherium). The fauna consists of medium to gigantic forms; sampling biases seem to influence collection of carnivorans as well as those of other mammals. All of these carnivoran genera have cosmopolitan distributions, and the occurrences from Myanmar fill their geological gap at Southeast Asia within Eurasia. Additionally, an indeterminate feliform was collected from the fauna. The Gwebin fauna (Late Pliocene) include a herpestid (Urva), a medium-sized felid, and a viverrid (Viverrinae). This first record of herpestid in the Pliocene of Asia confirms that the extant Asian mongoose lineage had already dispersed into Southeast Asia from South Asia by the Late Pliocene. Postcranial materials from the Sulegon area (Pliocene) provide evidences of additional taxa, a small felid and a large hyaenid. These recently collected carnivoran specimens revealed presence of diverse carnivorans from the Irrawaddy faunas. They fill geographical and/or chronological gaps of carnivoran distributions in Southeast Asia. Furthermore, the comparisons among carnivoran assemblages indicate faunal turnover of carnivorans at the family or subfamily level from the Late Miocene to the Late Pliocene of Myanmar.

著者

西岡 佑一郎 鍔本 武久 タウン ・ タイ ジン ・ マウン ・ マウン ・ テイン 高井 正成

出版者

日本古生物学会

雑誌

化石 (ISSN:00229202)

巻号頁・発行日

vol.104, pp.5-20, 2018-09-30 (Released:2019-04-03)

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The upper Neogene Pegu Group and Irrawaddy beds of Central Myanmar yield abundant perissodactyl and artiodactyl (cetartiodactyl) fossils. The upper Pegu or lowest Irrawaddy fauna is correlated with the middle Miocene Chinji fauna of the Siwalik Group, Indo-Pakistan, which contains Brachypotherium, Listriodon, and Microbunodon. The occurrence of Hipparion, Tetraconodon, Bramatherium, and some bovids (e.g., Selenoportax and Pachyportax) represents the early late Miocene fauna in Central Myanmar. Hipparion and Bramatherium disappeared in the latest Miocene or early Pliocene, while the bovids survived until this period. The latest Miocene/early Pliocene fauna is characterized by dominance of bovids and hippos (Hexaprotodon), which indicate the increase of grassland. The late Pliocene fauna is basically not different from the latest Miocene/ early Pliocene fauna because many perissodactyl and artiodactyl species continuously occur from both horizons of the Irrawaddy beds. Through the late Neogene, there were a few times of faunal and floral changes in continental Southeast Asia, and one of the remarkable change was during the late Miocene. Many forest dwellers that existed in the middle Miocene to early late Miocene were probably extinct at least before the latest Miocene when grasslands or open woodlands expanded in Central Myanmar.

著者

廣瀬 浩司 籔本 美孝 ブリトー パウロ M.

出版者

日本古生物学会

雑誌

化石 (ISSN:00229202)

巻号頁・発行日

vol.105, pp.1-2, 2019-03-30 (Released:2019-04-17)

著者

藤川 将之

出版者

日本古生物学会

雑誌

化石

巻号頁・発行日

vol.96, 2014

著者

郡司 幸夫

出版者

日本古生物学会

雑誌

化石 (ISSN:00229202)

巻号頁・発行日

vol.40, pp.17-34, 1986

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生物の分布は種の様々な環境要素に対する耐性, 移動様式, 種間競争等によって決まるが, 群集構造の認識はこの分布様式によって与えられると考えられる.生物種の耐性が比較的狭い場合は, 群集を物理化学的環境への適応種群の組み合わせとして認識できる(Chinzei and Iwasaki, 1967; Chinzei, 1978).しかし筆者が扱った腕足動物群集は各種の耐性が広く, 観察した環境下での種の分布はすみ分けの一種であると考えられる.このようなすみ分けは, 生物が増殖と移動を繰り返して種間で競争する場合, 増殖または移動様式がある環境要素の関数になっていれば, 容易に実現されることが数値計算により明らかとなった.したがって逆に分布を調べることで, 種間関係から群集を特徴づけられることがわかった.そこで, 実際にある条件下で適用できる静的競争系モデルを用い, 各種の深度に対する分布, 種間の個体数相関係数から, 種間関係を解析した.その結果, 屋久島・種子島近海の腕足動物群集は次のように認識された.第1に130〜170mの深度に生息適性を有する競争系が存在する.ここではC. pacifica, G. tokionis, G. hanzawai, C. basilanicaの順に順位づけられる.第2に共存し得る競争系が存在し, 第1の系と第2の系は, G. tokionis, C. basilanicaとB. lucidaが共存し得るような強い種間関係をもつことで結びついている.第3に, 以上2つの系とは強い種間関係をもたず, 含泥率の低い環境に適応したP. pictaが認められる.機能形態学がRudwick (1964)以前の適応主義一辺倒からSeilacher (1970)のBauplan的視点へ進んだ歴史を見, とりわけ構造的制約が注目されていることを考えても, 群集を構成する材料単位としての種の種間関係を解析していくことは今後更に必要となろう.近年種間競争の数学的解析がすすみ, May and Leonard (1975)は3種競争系の安定性を論じ, Mimura (1979)は捕食者-被捕食者系の空間分布を論じている.筆者の議論は, このような動力学的扱いから種間競争の解析をし, その要素を取り入れて群集を認識しようとする一つの試みである.

著者

鎮西 清高

出版者

日本古生物学会

雑誌

化石 (ISSN:00229202)

巻号頁・発行日

vol.31, pp.27-34, 1982-06-21 (Released:2017-10-02)

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Some paleoecologic aspects of oysters are discussed, giving special emphasis on the adaptive strategy of Crassostrea to the soft muddy bottom. Crassostrea is most abundant in the muddy intertidal facies despite their sessile and suspension feeding habit. Muddy bottom environment seems unfavorable for oysters because it offers very few basis of attachment, and gives continuous danger of suffocation by rapidly accumulating mud. Crassostrea surmounts these difficulties in living on mud, and becomes dominant in this environment. The basic strategy of Crassostrea for the survival in the muddy bottom is considered to be their gregarious tendency to constitute the densely aggregated colony. The colony supports the individual shell to stand above the surface of mud, and gives the firm basis for the attachment of later generations. The later generations grow on the colony, thus manage to keep living animals atop the rising mud level. Formation of the biohermal reef is the consequence of this characteristic behavior of Crassostrea. Nongenetic variations in shell morphology are conspicuous among Crassostrea individuals. The shell outline of fossil and living Crassostrea gigas is not controlled by the population density, but is probably related to the position of the shell : individuals in the upright position tend to be elongated irrespective of their density, and those lying on the bottom are usually more rounded. The population density apparently affects the individual shell size. Where the density is low, shells are very large, while they are small in densely populated reefs. The relationship may be explained by the competitive effect in the allocation of limited food supply.

著者

柏木 健司 山際 延夫 八尾 昭 江崎 洋一 酒折 有美子 庄司 康弘

出版者

日本古生物学会

雑誌

化石 (ISSN:00229202)

巻号頁・発行日

vol.72, pp.5-16, 2002

参考文献数

58

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1)紀伊半島西部, 和歌山県広川町の黒瀬川帯に分布する, 池之上層中部層に含まれる鳥巣式石灰岩から, 刺胞および海綿動物化石を報告した.刺胞および海綿動物化石の指示する年代はジュラ紀新世である.2)池之上層中部層の大部分は, 炭酸塩マウンド周辺に堆積した陸源砕屑岩が卓越する部分に相当する.炭酸塩マウンドそのものは1箇所でのみ認められる.散点的かつ小規模に含まれる鳥巣式石灰岩は, 岩酸塩マウンドから重力流により運搬され, 陸源砕屑岩中にブロックとして定置した.3)Kimmeridgianの頃, 陸側から古生代後期の緑色岩-石灰岩の巨大オリストリスが海溝陸側斜面上に多量に供給された.厚層のオリストストロームの堆積は, 海溝陸側斜面の浅海化を促進させた.4)Tithonian〜Berriacianにかけて, 海山列の付加に伴って海溝陸側斜面が急激に上昇し, 広範な浅海域が形成されるとともに, その浅海域に池之上層中部層や由良層などの鳥巣層群相当層が堆積した.

著者

梅田 真樹 江崎 洋一

出版者

日本古生物学会

雑誌

化石 (ISSN:00229202)

巻号頁・発行日

vol.62, pp.37-44, 1997-06-30 (Released:2017-10-03)

参考文献数

29

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The acidic tuffaceous strata in the Kanayama and Fukuji areas of the Hida "Gaien" (=Marginal) Terrane were previously designated as the Rosse Formation of Early Devonian time and the Mizuyagadani Formation of Early Permian time, respectively. However, the age of the extracted radiolarian fossils is different from the previously known age for the tuffaceous successions. The radiolarian fauna from the acidic tuffs is commonly characterized by Pseudoalbaillella fusiformis, Pseudoalbaillella sp. aff. P. longicornis and Follicucullus monacanthus, indicative of the F. monacanthus Zone of late Middle Permian. The stratigraphy should be revised thoroughly in those areas. The Middle Permian acidic tuffs are pervasive not only within the terrane but also among the adjacent terranes, indicating the prevalence of volcanic activity in the provenance. The present results are indispensable for the reconstruction of Permian paleogeography around Hida "Gaien" Terrane.

著者

梅田 真樹 江崎 洋一

出版者

日本古生物学会

雑誌

化石 (ISSN:00229202)

巻号頁・発行日

vol.62, pp.37-44, 1997

参考文献数

29

被引用文献数

4

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The acidic tuffaceous strata in the Kanayama and Fukuji areas of the Hida "Gaien" (=Marginal) Terrane were previously designated as the Rosse Formation of Early Devonian time and the Mizuyagadani Formation of Early Permian time, respectively. However, the age of the extracted radiolarian fossils is different from the previously known age for the tuffaceous successions. The radiolarian fauna from the acidic tuffs is commonly characterized by Pseudoalbaillella fusiformis, Pseudoalbaillella sp. aff. P. longicornis and Follicucullus monacanthus, indicative of the F. monacanthus Zone of late Middle Permian. The stratigraphy should be revised thoroughly in those areas. The Middle Permian acidic tuffs are pervasive not only within the terrane but also among the adjacent terranes, indicating the prevalence of volcanic activity in the provenance. The present results are indispensable for the reconstruction of Permian paleogeography around Hida "Gaien" Terrane.

著者

矢島 道子

出版者

日本古生物学会

雑誌

化石 (ISSN:00229202)

巻号頁・発行日

vol.73, pp.64, 2003-03-20 (Released:2017-10-03)

著者

速水 格

出版者

日本古生物学会

雑誌

化石 (ISSN:00229202)

巻号頁・発行日

vol.45, pp.45-48, 1988-12-15 (Released:2017-10-03)