著者

Kakui Keiichi Shiraki Shoki

出版者

The Crustacean Society

雑誌

Journal of Crustacean Biology (ISSN:02780372)

巻号頁・発行日

vol.41, no.2, pp.ruab026, 2021-06

被引用文献数

1

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Morphological diversity of sound-producing structures has not been well investigated among members of superorder Peracarida. Presumptive stridulatory sound-producing organs have been reported in some amphipods and tanaidaceans, and sound production by these organs has been documented in two isopod species in Oniscidea and Sphaeromatidea. Here we describe three presumptive stridulatory organs in the paranthurid isopod Paranthura cf. japonica Richardson, 1909, the first case known in Cymothoida. One type, consisting of a scale-bearing knob on the posterolateral corner of a pereonite and the scale-bearing anterolateral corner of the succeeding pereonite, was found between two pairs of pereonites (1, 2 and 2, 3). A second type involves a serrated structure in the sub-posterolateral region of pereonites 1 and 2, with the sharp anterolateral margins of pereonites 2 and 3 appearing to provide corresponding plectra. The third type involves an extension bearing a pair of serrated structures on the posteroventral margin of pereonites 1 and 2; the anterior-ventrolateral edges of pereonites 2 and 3 appear to provide corresponding plectra. All three organs occurred in both sexes of P. cf. japonica. Our discovery of novel, presumptive stridulatory organs in an intertidal isopod indicates that much remains to be learned about the biology of even common peracarid species.

著者

Kakui Keiichi Kajihara Hiroshi Kobayashi Norio

出版者

The Crustacean Society

雑誌

Journal of Crustacean Biology (ISSN:02780372)

巻号頁・発行日

vol.32, no.1, pp.127-139, 2012-01

被引用文献数

9

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Lack of an ischium on pereiopods 1–6 was previously considered a synapomorphy for the tanaidacean superfamily Tanaoidea, although descriptions of Arctotanais alascensis (Richardson, 1899), the sole species in Arctotanais, indicated presence or absence of the ischium. To resolve this ambiguity, we examined newly collected specimens of A. alascensis (including males, which had not previously been described) from Hokkaido, Japan, using light and scanning electron microscopy. We also conducted molecular phylogenetic analyses based on partial sequences of the 18S rRNA gene to examine the phylogenetic position of A. alascensis. Here we describe in detail the morphology of the male of A. alascensis, which proved to be similar to that of the females. This species bears an ischium on pereiopods 1–6, which contradicts the current diagnoses of Tanaoidea and Tanaidae, although other synapomorphies remain valid. Molecular phylogenetic analyses strongly supported the placement of A. alascensis in Tanaoidea, and consequently we amended the diagnoses for Tanaoidea and Tanaidae to include either presence or absence of the ischium on the pereiopods.