Species Diversity

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ISSN / EISSN : 1342-1670 / 2189-7301
Published by: Japanese Society of Systematic Zoology (10.12782)
Total articles ≅ 611
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Ryuichi Nakagawa, You Sakurai, Hiroyuki Motomura
Species Diversity, Volume 27, pp 15-23; https://doi.org/10.12782/specdiv.27.15

Seven specimens (149.0–221.2 mm standard length) of Pristipomoides amoenus (Snyder, 1911), previously known only from Okinawa-jima and Ishigaki-jima islands, southern Ryukyu Islands, Okinawa Prefecture, Japan, were collected from other regions of Japan (Amami-oshima island, Amami Islands, Kagoshima Prefecture), Taiwan (Dong-gang, Pingtung), the Philippines (Iloilo, Panay Island), and Fiji (Viti Levu Island), thereby representing the first records of the species from outside Okinawa Prefecture. The Amami-oshima and Fijian specimens also represent the northernmost and first Southern Hemisphere records, respectively, for the species. Comparison of these plus newly collected specimens from the southern Ryukyu Islands (herein described in detail) with the closely related species Pristipomoidesargyrogrammicus (Valenciennes in Cuvier and Valenciennes, 1832) revealed the following hitherto unrecognized diagnostic color features of P. amoenus: a few small silvery-blue blotches present inside yellow saddles on dorsum; small silvery-blue blotches below trunk lateral line absent or indistinct; a distinct line (formed by small silvery-blue blotches) absent on lower caudal peduncle; a large silvery-blue blotch present on upper opercle, extending anteriorly beyond preopercular margin; a line formed by small silvery-blue blotches on upper caudal peduncle ending at upper caudal-fin base; a pair of lines formed by small silvery-blue blotches along dorsal-fin base (dorsal view); a larger pair of elliptical silvery-blue blotches on occipital region (all silvery-blue blotches retained as dark-brown blotches after preservation). Pristipomoidesargyrogrammicus is newly recorded from the Tokara Islands, northern Ryukyu Islands, Japan.
Koichi Hoshino, Kunpei Kosaka, Kota Sawada, Masashi Kiyota
Species Diversity, Volume 27, pp 1-13; https://doi.org/10.12782/specdiv.27.1

An oreosomatid of the genus Allocyttus McCulloch, 1914 is fished commercially on the Emperor Seamounts. However, the species’ identity is uncertain, as is the taxonomy of the oreosomatid species of the seas around Japan, where the names Allocyttus verrucosus Gilchrist, 1906 (type locality: off South Africa) and A. folletti Myers, 1960 (type locality: off California) have both been used. From its anticipated susceptibility to over-exploitation, it is urgent to establish the correct taxonomic identity to facilitate effective management measures. Meristics, morphometrics and scale characters of the specimens from the Emperor Seamounts and Japan agreed well with data of the holotype of A. folletti and differed from those of A. verrucosus, confirming that those specimens represent A. folletti. Oreosomatids reported from the western North Pacific in the literature were identified as A. folletti. From the data of the present study and historical references, A. folletti is thought to be distinguished from A. verrucosus by the following characters: more dorsal- and anal- spines+rays (36–42 vs. 33–38 and 31–35 vs. 27–33 respectively), more total vertebrae (37–41 vs. 34–38), greater numbers of enlarged scales of dorsal- (S-DFB) and anal-fin base (S-AFB) (31–42 vs. 26–31, and 29–37 vs. 25–28 respectively), more spines on the margin of S-DFB and S-AFB (up to 7–12 vs. 3–6), a shorter preanal-fin length (53.8–63.6% vs. 64.8–83.7% of SL), a longer caudal peduncle (10.4–15.6% vs. 6.1–10.2% of SL), a shorter head (32.9–40.4% vs. 38.5–48.4% of SL), and cycloid scales on the mid-side of body (vs. ctenoid). Available data indicate that A. folletti reaches up to 537 mm SL, larger than A. verrucosus (up to ca. 325 mm SL). From the anticipated slow growth and longevity, concern is raised regarding the susceptibility of A. folletti to over-exploitation.
Hiroshi Kajihara
Species Diversity, Volume 27, pp 25-35; https://doi.org/10.12782/specdiv.27.25

The three heteronemertean nominal species Ascaris longissima Gunnerus, 1770, Borlasia angliae Oken, 1815, and Nemertes borlasii Cuvier, 1816 have been considered as synonymous, denoting the same species to which the valid name Lineus longissimus (Gunnerus, 1770) has been applied. These three nominal species are the type species of the genus-group names Lineus Sowerby, 1806, Borlasia Oken, 1815, and Nemertes Cuver, 1816, respectively, which are in turn the type genera of the family-group names Lineidae McIntosh, 1874, Borlasiidae Diesing, 1862, and Nemertidae Ehrenberg, 1831. Therefore, Lineus Sowerby, 1806 (currently in use) is a senior subjective synonym of Borlasia Oken, 1815 and Nemertes Cuvier, 1816 (both currently not in use), while Lineidae McIntosh, 1874 (currently in use) is a junior subjective synonym of Borlasiidae Diesing, 1862 and Nemertidae Ehrenberg, 1831 (both currently not in use); in addition, Micruridae Ehrenberg, 1831 (not in use) is also a senior synonym of Lineidae McIntosh, 1874. Borlasiidae Diesing, 1862 and Nemertidae Ehrenberg, 1831 have not been used as valid after 1899, while Lineidae McIntosh, 1874 has been used in at least 216 works published by 437 authors since 1971 until 2021, thus satisfying the conditions stipulated in Article 23.9.1 of the International Code of Zoological Nomenclature. Borlasiidae Diesing, 1862 and Nemertidae Ehrenberg, 1831 are herein declared nomina oblita with respect to Lineidae McIntosh, 1874, the latter being regarded as a nomen protectum under Article 23.9.2 of the International Code of Zoological Nomenclature. However, reversed precedence of Lineidae McIntosh, 1874 over its senior synonym Micruridae Ehrenberg, 1831 requires a ruling by the International Commission on Zoological Nomenclature, as the latter name was used as valid between 1998 and 2009
Kazuya Nagasawa, Masato Hirose
Species Diversity, Volume 26, pp 289-296; https://doi.org/10.12782/specdiv.26.289

An ovigerous female of a fish ectoparasite Argulus caecus C. B. Wilson, 1922 was collected from a squid, probably Todarodes pacificus (Steenstrup, 1880), from a fixed net installed in Otsuchi Bay, an inlet of the northwestern Pacific Ocean, Iwate Prefecture, northen Japan. Since the original description of A. caecus was insufficient, this paper reports on the morphology of the species based on a detailed examination of the female. In particular, the first and second antennae, the first and second maxillae, and four pairs of legs, whose features were poorly known, are reported in detail. The specimen of A. caecus is inferred to have detached itself and moved from a fish host, perhaps a coastal puffer, to the squid while these two animals were trapped in the net or when they were removed from the net. Following Argulus scutiformis Thiele, 1900, A. caecus is the second species of Argulus found from northern Japan located in the northern temperate or subarctic region, and its occurrence in this region is likely to be affected by the Tsushima Warm Current and its branch, the Tsugaru Warm Current, both of which flow off the coast of the region.
Masanori Nonaka, Takeshi Hayashibara
Species Diversity, Volume 26, pp 297-342; https://doi.org/10.12782/specdiv.26.297

Investigations were carried out on 22 deep-water octocoral specimens in the family Coralliidae sampled from the Emperor Seamounts during 2009 to 2012. The specimens were collected from 350–1100 m deep, mostly from the southernmost region of the Emperor Seamounts. Colonies were identified by visual and microscopic observation of standard morphological characters (colony size, diameters of colony base and branches, diameter and height of autozooid mound, thickness of coenenchyme and sclerite sizes, etc.) along with supporting information from molecular DNA analysis. Half of the 22 specimens were identified as Pleurocorallium cf. pusillum (Kishinouye, 1903), suggesting that the species called “Mid” that was once harvested dominantly in this area was this species. The remaining 11 specimens were identified as genus Hemicorallium Gray, 1867. These were identified as belonging to the following species: one previously described species [H. laauense (Bayer, 1956)], three similar species [H. cf. abyssale (Bayer, 1956), H. cf. regale (Bayer, 1956), H. cf. sulcatum (Kishinouye, 1903)] and three new species (H. kaiyo sp. nov., H. muzikae sp. nov. and H. tokiyasui sp. nov.).
Taiga Kunishima, Ken Maeda, Ryutei Inui, Yusuke Hibino
Species Diversity, Volume 26, pp 343-349; https://doi.org/10.12782/specdiv.26.343

A single specimen of Muraenichthys gymnopterus (Bleeker, 1853) was collected from a sandy intertidal flat having rocks and dead corals in the estuarine area of Nagura Amparu, Ishigaki-jima Island, southern Japan, in October 2020. This specimen collection constitutes the first record of M. gymnopterus from Japanese waters. In this study, the diagnostic characters between M. gymnopterus and M. hattae Jordan and Snyder, 1901 are provided, based on our morphological observations of 37 specimens, including Okinawan specimen, and previous studies, as follows: head length [M. gymnopterus 11.8–15.0% of total length (TL) vs. M. hattae 9.4–11.0%], trunk length (24–25.4% of TL vs. 28–31%), the horizontal distance from the dorsal-fin origin to a vertical line through the anus 73–87% of head length vs. 13–49%), the number of vertebrae (total 129–130 vs. 148–155; predorsal 30 vs. 47–53; preanal 41–44 vs. 51–55), the number of the lateral-line pores before the anus (43–45 vs. 51–55). Additionally, the body depth at the gill opening in TL and the trunk length in TL can also be used to distinguish between these two species (2.8–3.7% of TL vs. 1.4–3.0%). Although M. gymnopterus has previously been reported from tropical to temperate regions, we suspect that the records from temperate regions are based on misidentification of M. hattae.
Kentaro Mochizuki, Yoshiaki Kai, Hiromitsu Endo, Hiroyuki Motomura
Species Diversity, Volume 26, pp 281-287; https://doi.org/10.12782/specdiv.26.281

Ocosia spinosa Chen, 1981 (Tetrarogidae) is newly recorded from the Pacific coast of Japan, on the basis of 10 specimens (31.3–78.1 mm standard length), having been previously reported only from Taiwan. A revised diagnosis for the species, based on the Japanese specimens plus a single specimen from Taiwan, is given as follows: XV–XVIII, 7 or 8 dorsal-fin rays; III, 4–6 anal-fin rays; usually 13 (rarely 12) pectoral-fin rays; 12–18 lateral-line pores on body; 6–15 gill rakers; usually 28 (rarely 27) vertebrae; 2nd dorsal-fin spine longest, slightly longer than 3rd spine; interspinous dorsal-fin membranes of middle portion of dorsal fin incised for one-fourth to one-third of each spine length; dorsal profile of snout concave; posterior lacrimal spine directed backward, its length about 2–3 times greater than that of anterior lacrimal spine; small lateral lacrimal spine usually present (absent in larger specimens); small spine usually present at anterior end of suborbital ridge in smaller specimens (absent in larger specimens); weak stubby papillae covering upper lip and anterior half to one-third of lower lip; trunk uniformly brownish-red when fresh, without distinct markings (but with faint brownish small blotch near base of middle portion of dorsal fin in some individuals). Although the presence or absence of small spines on the lateral surface of the lacrimal and anterior end of the suborbital ridge has previously been regarded as an important diagnostic character of O. spinosa, examination of the present specimens showed that the character changes with growth. The present specimens represent the first Japanese records, as well as the northernmost and easternmost records for the species. The new English and Japanese standard names “Red Waspfish” and “Aka-hachiokoze”, respectively, are proposed for O. spinosa.
Tsukasa Waki, Mizuki Sasaki, Hajime Matsubara, Satoshi Shimano
Species Diversity, Volume 26, pp 273-279; https://doi.org/10.12782/specdiv.26.273

The feather mite Pseudalloptinus milvulinus (Trouessart, 1884) was collected from feathers of the Black Kite Milvus migrans (Boddaert, 1783) in Ishikawa Prefecture, Japan, in 2019. The identification of this mite was based on the form and arrangement of setae on the idiosoma and aggenital region. This study is the first report of this mite species and the genus Pseudalloptinus Dubinin, 1956 in Japan.
Yuzo Ota, Hisanori Kohtsuka, Katsuhiko Tanaka
Species Diversity, Volume 26, pp 207-216; https://doi.org/10.12782/specdiv.26.207

Adult male and larva of Gnathia capitellum sp. nov. (Crustacea: Isopoda: Gnathiidae) are described. The specimens were laboratory-reared larvae that infested host fishes collected by longline fishing in a coastal bay of Izu Peninsula and adult males found in dredge samples from shallow water (depth: 11–12 m) of Miura Peninsula, central Japan. Adult males of G. capitellum sp. nov. were easily distinguished from the other species of Gnathia Leach, 1814 from around the world by the small oval head and the inner margin of pylopod without plumose setae. Most other Gnathia species have a large rectangular head and plumose setae present on the article 1 of pylopod. Appearance of the adult male resembles the genus Afrignathia Hadfield and Smit, 2008 rather than Gnathia but Afrignathia has maxilla 1 which is absent in all known male gnathiids in the world including G. capitellum sp. nov. Fish parasitic larva of G. capitellum sp. nov. is also described herein. This larva closely resembles larvae of the genus Gnathia, but can be distinguished from the other Gnathia species by the remarkably oval-shaped basis in pereopods 2–4.
Harutaka Hata, Hiroyuki Motomura
Species Diversity, Volume 26, pp 197-204; https://doi.org/10.12782/specdiv.26.197

Eighteen specimens of Sardinella gibbosa (Bleeker, 1849) collected from Okinawa Island, Ryukyu Islands, Japan represent the first Japanese specimen-based records of the species. All specimens conformed closely to the diagnosis of S. gibbosa, having the caudal fin uniformly pale, a black spot on the dorsal-fin origin, body scales with centrally discontinuous striae, 26−31+50–57=77–88 gill rakers on the first gill arch, and 18 or 19+14 or 15=32–34 keeled scutes along the body ventral surface. In addition, some previous Japanese records of unidentified clupeoid fishes are reviewed.
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