Author
Masayuki Oishi
Bio: Masayuki Oishi is an academic researcher. The author has contributed to research in topics: Whale & Cetacea. The author has an hindex of 2, co-authored 2 publications receiving 150 citations.
Topics: Whale, Cetacea, Balaenoptera, Baleen whale, Balaenoptera brydei
Papers
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TL;DR: A new species of Balaenoptera is described, characterized by its unique cranial morphology, its small number of baleen plates, and by its distant molecular relationships with all of its congeners.
Abstract: In the late 1970s eight Balaenoptera specimens of unknown identity were caught in the lower latitudinal Indo-Pacific waters by Japanese research whaling vessels1. The combination of the allozyme patterns and physical maturity of the eight specimens separated them from all acknowledged Balaenoptera species2. In September 1998 we collected a medium-sized baleen whale carcass on a coastal island in the Sea of Japan. This specimen and the previously collected eight specimens resembled Balaenoptera physalus (fin whale) in external appearance but were much smaller. Comparison of external morphology, osteology and mitochondrial DNA data grouped the nine specimens as a single species but separated them from all known baleen whale species. Therefore, here we describe a new species of Balaenoptera, which is characterized by its unique cranial morphology, its small number of baleen plates, and by its distant molecular relationships with all of its congeners. Our analyses also separated Balaenoptera brydei (Bryde's whale)3,4 and Balaenoptera edeni (Eden's whale)5 into two distinct species, raising the number of known living Balaenoptera species to eight.
165 citations
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01 Jan 2009
TL;DR: Balaenoptera edeni Anderson, 1878/9, 、いわゆるニタリクジラB.
Abstract: 近年、ツノシマクジラBalaenoptera omurai Wada, Oishi et Yamada, 2003 が新たに記載された際 に、いわゆるニタリクジラBalaenoptera edeni Anderson, 1878/9 はカツオクジラB. edeni と狭義 のニタリクジラBalaenoptera brydei Olsen, 1913 に分けられることが指摘された。筆者らによる 台湾やタイなどの調査では、これら 3 種の中型のナガスクジラ科鯨類が多数存在することがわかっ ているが、比較できる標本が増えたことで、頭頂部の形態学的特徴に加えて、翼蝶形骨周辺の脳 頭蓋側面の形態でも 3 種が明瞭に識別できることがわかってきている。和歌山県立自然博物館と 大分県杵築市立図書館には、かつていわゆるニタリクジラB. edeni として報告されたナガスクジ ラ科鯨類標本が保管されているが、カツオクジラB. edeni のホロタイプを含む既報告の標本の頭 頂部と翼蝶形骨の形態の比較により、これらの標本はカツオクジラB. edeni であると判断される。 要 旨
2 citations
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TL;DR: Seven guidelines are proposed to help integrative taxonomists recognize cases when species are supported by broad biological evidence and therefore are deserving of an official name and to prevent the over-abundance of both synonyms and names of doubtful application from worsening.
Abstract: Delineating species boundaries correctly is crucial to the discovery of life’s diversity because it determines whether or not different individual organisms are members of the same entity. The gap in communication between the different disciplines currently involved in delimiting species is an important and overlooked problem in the so-called ‘taxonomy crisis’. To solve this problem, it is suggested that taxonomy become integrative, and this integration is seen as the real challenge for the future of taxonomy. ‘Integrative taxonomy’ is defined as the science that aims to delimit the units of life’s diversity from multiple and complementary perspectives (phylogeography, comparative morphology, population genetics, ecology, development, behaviour, etc.). Some workers have already collaborated and successfully adopted an integrative approach to taxonomy. However, it is now time for the whole discipline to evolve. A radical change in mentality is needed concerning the creation of names in order to achieve this integration and to prevent the over-abundance of both synonyms and names of doubtful application from worsening. Integrative taxonomy gives priority to species delineation over the creation of new species names. Furthermore, it is emphasized that describing morphological diversity, referred to as ‘morphodiversity’, does not require the naming of any single set of specimens. Seven guidelines are proposed to help integrative taxonomists recognize cases when species are supported by broad biological evidence and therefore are deserving of an official name. © 2005 The Linnean Society of London, Biological Journal of the Linnean Society , 2005, 85 , 407‐415. ADDITIONAL KEYWORDS: biodiversity ‐ character variation ‐ DNA barcoding ‐ ecology ‐ morphodiversity ‐ phylogenetics ‐ phylogeography ‐ population biology ‐ species delineation ‐ systematics.
1,451 citations
01 Jan 2006
TL;DR: The second phase of IGBP as mentioned in this paper describes a strategy for producing high quality, unbiased, credible, fundamental scientific research in the area of global change: a strategy centered on ten projects.
Abstract: This Science Plan and Implementation Strategy sets out the research agenda for the second phase of IGBP The document describes the IGBP strategy for producing high quality, unbiased, credible, fundamental scientific research in the area of global change: a strategy centered on ten projects, to be carried out by the several thousand scientists worldwide who are part of the IGBP network Further, the document describes how the organization will communicate the results of this research to different audiences, in order to realize its vision: "to provide scientific knowledge to improve the sustainability of the living Earth"
364 citations
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01 Jan 2009
TL;DR: This lexicon is an attempt to remedy that situation in that it provides headwords and definitions for all the terms that have been used in describing the mammal skull and notes the synonymous terms.
Abstract: Mead, J. G., and R. E. Fordyce. The Therian Skull: A Lexicon with Emphasis on the Odontocetes. Smithsonian Contributions to Zoology, number 627, 248 pages, frontispiece, 2 diagrams, 32 figures, 9 tables, 2009. — Cetaceans form one of the most unique groups in the evolutionary history of mammals. They have returned to the sea and modified their tail as an efficient means of locomotion. As they adapted to the limited visibility in the aquatic environment, the odontocetes developed a system of echolocation that resulted in extensive modifications to the skull bones. This made descriptive comparisons very difficult and early anatomists unwittingly composed new terms for anatomical structures that had already been named in other taxa. This made anatomical comparisons, based on the literature, extremely tenuous. This lexicon is an attempt to remedy that situation in that it provides headwords and definitions for all the terms that have been used in describing the mammal skull and notes the synonymous terms. The lexicon includes the human nomenclature (Nomina Anatomica), the veterinary nomenclature (Nomina Anatomica Veterinaria) and the nomenclature that is used in descriptive comparative anatomy. The lexicon covers not only extant but extinct mammalian groups and is extensively indexed. Cover: Detail from Frontispiece, illustration of a dolphin skull (cf. Delphinus sp.) presented by
320 citations
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TL;DR: It is suggested that taxonomic revisions that recognize cryptic or polytypic species will lead to even greater accuracy of DNA-based identification methods, as well as more accurate identification of paraphyletic and polyphyletic species.
Abstract: In recent years, research has shown that geographical variation in mitochondrial DNA of commensal rats provides a strong signal of human dispersal and migration. However, interpretation of genetic variation is complicated by the presence of multiple species of Rattus especially in Island Southeast Asia, by the occurrence of some of these Rattus sp. as subfossils in archaeological and natural sites, and by the difficulty of osteological identification of these remains. Amplification of DNA from ancient sources usually yields only small fragments (∼ 200 bp). We assessed whether we could identify Rattus sp. reliably with DNA barcoding using cytochrome oxidase I (COI) sequences, or tree-based methods using D-loop, cytochrome b and COI sequences. Species forming well-differentiated clades in a molecular phylogeny were accurately identified by both methods, even when we used short DNA fragments. Identification was less accurate for paraphyletic and polyphyletic species. We suggest that taxonomic revisions that recognize cryptic or polytypic species will lead to even greater accuracy of DNA-based identification methods.
186 citations
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TL;DR: Small isolated subspecies or subpopulations, such as northern Indian Ocean blue whales, Arabian Sea humpback whales, and Mediterranean Sea fin whales are threatened while most sub Populations of sei, Bryde’s, and Omura's whales are inadequately monitored and difficult to assess.
Abstract: No global synthesis of the status of baleen whales has been published since the 2008 IUCN Red List assessments. Many populations remain at low numbers from historical commercial whaling, which had ceased for all but a few by 1989. Fishing gear entanglement and ship strikes are the most severe current threats. The acute and long-term effects of anthropogenic noise and the cumulative effects of multiple stressors are of concern but poorly understood. The looming consequences of climate change and ocean acidification remain difficult to characterize. North Atlantic and North Pacific right whales are among the species listed as Endangered. Southern right, bowhead, and gray whales have been assessed as Least Concern but some subpopulations of these species - western North Pacific gray whales, Chile-Peru right whales, and Svalbard/Barents Sea and Sea of Okhotsk bowhead whales - remain at low levels and are either Endangered or Critically Endangered. Eastern North Pacific blue whales have reportedly recovered, but Antarctic blue whales remain at about 1% of pre-exploitation levels. Small isolated subspecies or subpopulations, such as northern Indian Ocean blue whales, Arabian Sea humpback whales, and Mediterranean Sea fin whales are threatened while most subpopulations of sei, Bryde’s, and Omura’s whales are inadequately monitored and difficult to assess.
141 citations