著者

Jørgen Olesen Mark J. Grygier

出版者

The Japanese Society of Systematic Zoology

雑誌

Species Diversity (ISSN:13421670)

巻号頁・発行日

vol.27, no.2, pp.301-317, 2022-10-13 (Released:2022-10-13)

参考文献数

44

被引用文献数

4

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Two large (ca. 0.5 mm long), rare, and probably closely related species of Facetotecta (y-larvae), Hansenocaris cristalabri sp. nov. and Hansenocaris aquila sp. nov., are described on the basis of last-stage lecithotrophic nauplii reared from plankton at Sesoko Island, Okinawa, Japan. The two species resemble each other in having a labrum with a row of spines and a long, attenuate trunk region that terminates in a long, heavily spinose dorsocaudal spine. The labrum of H. cristalabri sp. nov. has an enormous, cockscomb-like ventral process that bears a row of distally directed, dagger-like spines along its anterior side, while the spine-bearing keel of the labrum of H. aquila sp. nov. extends posteriorly into a robust, eagle-like beak. The labral “crest” of H. cristalabri sp. nov. has no equivalent in any other described y-larva, nor in any other crustacean nauplius; its possible functions are discussed. Another diagnostic feature of H. cristalabri sp. nov., absent in H. aquila sp. nov., is a pair of shallow, rounded notches bounded by sharp spinules on the far posteriolateral margins of the cephalic shield. Both new species have longitudinal spine rows on the trunk dorsum, two rows in H. cristalabri sp. nov. and four in H. aquila sp. nov., something not previously documented for y-nauplii. The plate arrangement of the cephalic shield in H. cristalabri sp. nov. is described in detail, with an attempt to homologize the pattern with that of other y-nauplii (especially Hansenocaris furcifera Itô, 1989). The body surface of H. cristalabri sp. nov. has fewer setae and pores than any other late- or last-stage facetotectan nauplius described to date, suggesting paedomorphic development. A formal diagnosis is presented for the family-group taxon Hansenocarididae fam. nov.; this name, while already in use, has until now been nomenclaturally unavailable.

著者

中野 隆文 Mark J. Grygier

出版者

日本動物分類学会

雑誌

タクサ:日本動物分類学会誌 (ISSN:13422367)

巻号頁・発行日

vol.44, pp.64-68, 2018-02-28 (Released:2018-03-20)

参考文献数

14

著者

Hiroshi Kajihara Mariko Takibata Mark J. Grygier

出版者

日本動物分類学会

雑誌

Species Diversity (ISSN:13421670)

巻号頁・発行日

vol.21, no.2, pp.105-110, 2016-11-25 (Released:2017-02-03)

参考文献数

26

被引用文献数

1

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The freshwater heteronemertean Apatronemertes albimaculosa Wilfert and Gibson, 1974 has previously been reported from Germany, Austria, and the USA. All these records were from aquarium tanks with commercially distributed tropical and/or subtropical water plants; by hiding among their roots, the worms are thought to have been introduced from an unidentified place of origin. We report the occurrence of A. albimaculosa for the first time from Japan, based on specimens found in private home aquaria for guppy breeding, with a total of 18 species of water plants grown for different periods and lengths of time but not all at the same time. Histological examination confirmed the presence of diagnostic features of this species, including a complex precerebral vascular system and hermaphroditism. The partial sequence of the mitochondrial cytochrome c oxidase subunit I gene (607 bp) of the Japanese material is identical with that of a heteronemertean specimen from a freshwater tank in Madrid, Spain, which had been deposited in the public databases but left unidentified as to its species, genus, or family. Apatronemertes albimaculosa appears unlikely to be able to survive below 10°C for more than about a week, which suggests that its native locality is in the tropics or subtropics, not the temperate zone. The barcoding sequence herein determined will serve in future studies to help locate the natural place of origin.