著者

Kakui Keiichi Hiruta Chizue

出版者

John Wiley & Sons

雑誌

Journal of Morphology (ISSN:03622525)

巻号頁・発行日

vol.275, no.9, pp.1041-1052, 2014-09

被引用文献数

14

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Among arthropods, various insects, spiders, and crustaceans produce thread. The crustacean Tanaidacea include species that use thread mainly to construct dwelling tubes. While thread production was previously known only in Tanaoidea and Paratanaoidea, it was recently discovered in two species in Kalliapseudidae (Apseudoidea), although information on the morphology of the thread‐producing system was lacking. Using histology, light and scanning electron microscopy, we found that the kalliapseudid Phoxokalliapseudes tomiokaensis comb. nov. lacks the sort of glandular structures associated with thread production in the pereonites, but has these structures in pereopods 1–6. We observed four types of glandular systems defined by the types and distribution of glands they contain: Type A (pereopod 1), Type B (pereopods 2 and 3), Type C (pereopods 4 and 5), and Type D (pereopod 6). All types have small rosette glands and lobed glands; Type A additionally has large rosette glands. The inferred thread‐producing apparatus in P. tomiokaensis is very different from that in Tanaoidea and Paratanaoidea, suggesting that kalliapseudids evolved thread production independently from the latter two groups. J. Morphol. 275:1041–1052, 2014. © 2014 Wiley Periodicals, Inc.

著者

Kakui Keiichi Munakata Mizuho Tanaka Hayato Hiruta Chizue

出版者

Elsevier

雑誌

Zoologischer Anzeiger (ISSN:00445231)

巻号頁・発行日

vol.293, pp.145-148, 2021-07

被引用文献数

1

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Ostracoda is a diverse group of tiny crustaceans. Although more than 9330 extant species have been described, whole-mitogenomic data were available for only five species. Here we present a complete mitogenomic sequence for an additional species, the parthenogenetic podocopan ostracod Heterocypris spadix. The mitogenome is 15,205 bp long and contains the typical animal mitogenomic complement of 13 protein coding, two ribosomal RNA, and 22 transfer RNA genes. In a mitogenome-based phylogenetic tree, Myodocopa and Podocopa were each monophyletic. Gene order in Podocopa was much more similar to the pancrustacean ground pattern than was gene order in Myodocopa. Gene order was invariant in the three myodocopan species examined, all in the family Cypridinidae. Within Podocopa, two species from different families (Fabaeformiscandona kushiroensis, Candonidae; H. spadix, Cyprididae) were identical in gene order and differed from the pancrustacean ground pattern by only a single recombination. In Cyprididae, however, Cypridopsis vidua differed from H. spadix by five rearrangements. These conflicting patterns—apparent gene-order conservation within (Cypridinidae) and between families (Cyprididae and Candonidae), but marked divergence within a family (Cyprididae)—suggest that the evolution of gene order in ostracods was more complex than that expected from the cypridinid data.

著者

Kakui Keiichi Hiruta Chizue

出版者

Zoological Society of Japan

雑誌

Zoological Science (ISSN:02890003)

巻号頁・発行日

vol.39, no.1, 2022-02

被引用文献数

6

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We describe a new typhlotanaid species, Hamatipeda kohtsukai sp. nov., collected from between 167 and 488 m depth in the Sagami Sea, Japan. This is the first record of Hamatipeda from the northern hemisphere. Hamatipeda kohtsukai resembles Hamatipeda trapezoida from the Subantarctic region in having pereonites 1–3 widest anteriorly (not rectangular), but differs from it in the length ratio of antennal articles 4/5; the number of setae on the dactyli of pereopods 1–3, ischia of pereopods 4–6, and carpi of pereopods 4–6; the shape of the unguis of pereopods 4–6; and the shape of the uropodal endopod. We determined partial sequences for the cytochrome c oxidase subunit I (COI; cox1) and 18S rRNA (18S) genes in H. kohtsukai. A phylogenetic reconstruction based on the 18S sequences recovered a highly supported Typhlotanaidae clade containing H. kohtsukai and Typhlotanais mixtus, with Paranarthrura sp. (Agathotanaidae) as the sister taxon. A key to species of Hamatipeda is presented.

著者

Kakui Keiichi Hiruta Chizue

出版者

NRC Research Press (Canadian Science Publishing)

雑誌

Canadian Journal of Zoology (ISSN:00084301)

巻号頁・発行日

vol.100, no.8, pp.481-487, 2022

被引用文献数

3

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Hermaphroditism has been widely reported in the Crustacea, but protogyny, in which females change to males, is apparently rare and restricted to the peracarid orders Isopoda and Tanaidacea. In the latter, protogyny has been demonstrated in only seven species representing six genera by rearing experiments and indicated for several other genera and species through morphology. Here, we show through rearing experiment and histological observations, protogynous hermaphroditism in the tanaidacean species Nesotanais sp. aff. ryukyuensis Kakui, Kajihara and Mawatari, 2010. Our rearing experiment and size distribution data for wild individuals showed that females can change sex at various sizes (= ages). We found one individual identified externally as a female containing both ovaries and testes, indicating that overt female individuals undergo a short transitional phase as simultaneous hermaphrodites before the sex-change molt. We discuss the relationship among the wide size distribution of sex-changing females, the short life span of males, and the tube-dwelling mode of life.

著者

Kakui Keiichi Hiruta Chizue Uyeno Daisuke

出版者

Wiley

雑誌

Invertebrate Biology (ISSN:10778306)

巻号頁・発行日

vol.138, no.3, pp.e12257, 2019-09

被引用文献数

3

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With more than 40,000 species, Malacostraca is the most diverse crustacean class. Most malacostracans are gonochoristic, but simultaneous hermaphrodites are also known. Tanaidacea is one of two malacostracan orders that includes simultaneously hermaphroditic species; so far, simultaneous hermaphroditism has been confirmed externally and internally in only two tanaidacean species, both in the genus Apseudes (Apseudidae). Here we show, through external and internal morphological observations of fixed specimens, that the apseudid Falsapseudes bowmani is a simultaneous hermaphrodite, making Falsapseudes the second tanaidacean genus in which simultaneous hermaphroditism has been confirmed both externally and internally. In this species, the epistome (a projection on the clypeus) was thick and elongate in large specimens but was thin and spiniform in smaller specimens; the brooding of eggs or embryos was observed only in thin-epistome individuals, although a pair of ovaries was confirmed in both thick- and thin-epistome individuals. This suggests that individuals with a thick epistome may act as males while also retaining the female reproductive organs.

著者

Kakui Keiichi Hiruta Chizue

雑誌

Naturwissenschaften (ISSN:00281042)

巻号頁・発行日

vol.100, no.9, pp.891-894, 2013-09

被引用文献数

9

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The crustacean class Malacostraca,with over 22,000 species, includes commercially important members, such as crabs, shrimps, and lobsters. A few simultaneous hermaphrodites are known in this group, but self-fertilization was unknown. Here we show, through microscopy and breeding experiments, that the simultaneously hermaphroditic malacostracan Apseudes sp. (order Tanaidacea) can self-fertilize; individuals reared in isolation become hermaphroditic via a male-like phase and produce eggs that develop into fertile adults. Although selfing occurs in crustaceans like the Branchiopoda, in which simultaneous hermaphrodites have the sex ducts united, in decapods the separation of gonadal ducts and gonopores, specialized mating organs, and complex mating behavior appear to have constrained the evolution of selfing. In contrast, in most tanaidaceans, sperm is released externally by a male and reaches the eggs in the female brood pouch, where fertilization occurs. This mode of fertilization permitted Apseudes sp. to achieve selfing without large modifications in morphology or behavior.