- 著者
- Ko Tomikawa Yuji Abe Takafumi Nakano
- 出版者
- The Japanese Society of Systematic Zoology
- 雑誌
- Species Diversity (ISSN:13421670)
- 巻号頁・発行日
- vol.24, no.2, pp.259-266, 2019-11-25 (Released:2019-11-25)
- 参考文献数
- 10
- 被引用文献数
- 5
A new species of pseudocrangonyctid amphipod, Pseudocrangonyx uenoi, is described from cave streams in Taga town, central Honshu, Japan. Previous molecular phylogenetic studies reported the taxonomic status of the Taga populations of Pseudocrangonyx as an undescribed species. We present the diagnostic features to discriminate P. uenoi from the other congeners on the basis of morphological study. Pseudocrangonyx uenoi is closely related to P. daejeonensis Lee, Tomikawa, Nakano, and Min, 2018, but clearly distinguished from the latter by the presence of calceoli on female antenna 2, the 5-dentate lacinia mobilis of the left mandible, setation of the peduncular articles of pleopods, the number of articles of rami of the pleopods, a shorter terminal article of uropod 3, and a telson with a deeper cleft.
- 著者
- Ko Tomikawa Makio Yanagisawa Takuo Higashiji Nagisa Yano Wim Vader
- 出版者
- The Japanese Society of Systematic Zoology
- 雑誌
- Species Diversity (ISSN:13421670)
- 巻号頁・発行日
- vol.24, no.2, pp.209-216, 2019-10-25 (Released:2019-10-25)
- 参考文献数
- 40
- 被引用文献数
- 4
A new species of podocerid amphipod, Podocerus jinbe, is named and described. This new species was collected from the gill rakers of the whale shark Rhincodon typus Smith, 1828 from off Yomitan Village, Okinawa Island, Japan. This is the first record of an amphipod associated with the whale shark. Podocerus jinbe sp. nov. is morphologically similar to P. zeylanicus (Walker, 1904), but differs from the latter by its larger body size, shorter peduncular article 1 of antenna 1, longer flagellar article 1 of antenna 1, subrectangular propodus of male gnathopod 1, anteriorly concave basis of male gnathopod 2, narrow merus of female gnathopod 2, greater number of robust setae on rami of uropods 1 and 2, and greater number of long robust setae on the telson apical lobe. Additionally, a partial DNA sequence of the mitochondrial cytochrome c oxidase subunit I (COI) of this species was determined for future studies.
- 著者
- Ko Tomikawa Norio Kobayashi Hiroshi Morino
- 出版者
- The Japanese Society of Systematic Zoology
- 雑誌
- Species Diversity (ISSN:13421670)
- 巻号頁・発行日
- vol.21, no.1, pp.55-64, 2016-05-25 (Released:2017-02-01)
- 参考文献数
- 26
- 被引用文献数
- 1
The taxonomic subdivision of certain Japanese freshwater amphipods into Jesogammarus jesoensis (Schellenberg, 1937), J. hokurikuensis Morino, 1985, J. fujinoi Tomikawa and Morino, 2003, and J. shonaiensis Tomikawa and Morino, 2003 was reassessed using both morphological and molecular data. Putative diagnostic morphological characters did not exhibit consistent geographic distributions, but eight geographically consistent monophyletic clades were detected based on COI and COI+12S rRNA sequence data. Uncorrected COI nucleotide divergences between the clades ranged from 7.0% to 16.4%, a level usually considered to represent inter-specific differences in crustaceans. No morphological features that differentiate the molecular clades were found. While the formal nomenclatural handling of these findings remains a problem for the future, for now we suggest the use of the term “J. jesoensis complex” to represent taxonomic entity consisting of the nominal taxa J. jesoensis, J. fujinoi, J. shonaiensis, and J. hokurikuensis, and potentially a number of hitherto cryptic taxa as well.
- 著者
- Ko Tomikawa Teruo Ishida Shunsuke F. Mawatari
- 出版者
- The Japanese Society of Systematic Zoology
- 雑誌
- Species Diversity (ISSN:13421670)
- 巻号頁・発行日
- vol.10, no.1, pp.19-26, 2005-02-28 (Released:2018-03-30)
- 参考文献数
- 13
- 被引用文献数
- 3
A new species of cyclopoid copepod, Allocyclops (Allocyclops) austronipponicus, is described from a freshwater habitat in Okinawa Island, Japan. This is the first record of the genus Allocyclops from Asia. The new species is distinguished from its congeners by having the following combination of character states: (1) antennal seta representing exopod present; (2) maxillule with two-segmented palp; (3) legs 1-4 each with inner coxal seta; (4) distal endopodal segment of leg 4 with three inner and one outer setae and two apical spines; and (5) seta present on remnant of proximal segment of leg 5, this seta short in comparison to length of somite.