taxonID	type	description	language	source
A34681131A6CFFC4FF54FC6B2A272E30.taxon	description	(Figs 1 – 2)	en	Nitta, Yusuke Kamio and Masato (2025): Redescription of Microcotyle elegans (Polyopisthocotyla: Microcotylidae) from Scombrops boops (Perciformes: Scombropidae) off Japanese Waters. Species Diversity 30 (2): 111-125, DOI: 10.12782/specdiv.30.111, URL: https://doi.org/10.12782/specdiv.30.111
A34681131A6CFFC4FF54FC6B2A272E30.taxon	description	Redescription. Body (Fig. 1) elongated, 2225 – 5600 (3989, n = 20) long including haptor, 275 – 925 (570, n = 22) wide at level of germarium. Haptor wedge-shaped, subsymmetrical, with 48 – 95 (68, n = 14) clamps, arranged in 2 subequal lateral rows. Clamps (Fig. 2 C) of equal structure, each clamp 50 – 90 × 75 – 135 (75 × 116, n = 14) in diameter. Clamps of Microcotyle - type, formed by two jaws. Ventral arm of median spring long, thin, ends distally in an inverted T, with short branches. Lateral sclerites of ventral jaw approaching midline distally. Dorsal arm of median spring inverted Y- shaped. Posterolateral sclerite and anterolateral sclerites curved toward inside. Pair of buccal suckers (Fig. 1) septate, elliptical, 65 – 120 × 70 – 125 (89 × 90, n = 21). Pharynx (Fig. 1) globular, immediately posterior to buccal sucker, sometimes overlapping buccal sucker, 70 – 95 × 55 – 105 (84 × 73, n = 20). Esophagus (Fig. 1) short, without lateral diverticula. Intestinal bifurcation (Fig. 1) behind genital atrium. Intestinal ceca (Fig. 1) blind, extending to haptor, with numerous lateral diverticula, not united posteriorly. Testes (Figs 1, 2 A) with irregular shape, 16 – 28 (22, n = 21) in number, post-ovarian, intercaecal, in posterior half of body. Vas deferens (Fig. 2 A) long, narrow, coming from anterior of testes, ventral to germarium, extending anteriorly, dorsal to uterus along its dorsal side, entering base of genital atrium. Genital atrium (Figs 1, 2 B) mushroom-shaped, 190 – 400 × 150 – 300 (289 × 218, n = 21), located posterior to pharynx, with lateral expansions, surrounded by radiate muscle fibers. Genital atrium comprises anterior atrium proper and a posterior pocket. Genital atrium proper bearing numerous small spines, 161 – 210 (189, n = 8) in number. Edge of genital atrium opening and its inner walls armed with numerous conical spines, 5 – 7 (6, n = 22) in length. Spines more dense in central anterior region, less dense in lateral pockets; no spines present in center of posterior pockets; lateral margin with row of longer spines, 7 – 10 (9, n = 10) long in posterior pockets. Germarium complex (Figs 1, 2 A) begins at level of anteriormost testes, continuing anteriorly in midline, reflexing approximatively at level of confluence of vitelline ducts, reflexing again toward anterior extremity, forming an equally thin anterior curve and reflexing a last time posteriorly before ending as oviduct, 350 – 800 (556, n = 12) long, 270 – 750 (382, n = 12) wide. Oviduct (Figs 1, 2 A) wide, twisted, dorsal to receptaculum seminis, arising from distal end of germarium, extending towards anterior of testes, connected to receptaculum seminis and vitelline duct. Genito-intestinal canal (Figs 1, 2 A) originates from right intestinal cecum and connecting to receptaculum seminis. Receptaculum seminis (Figs 1, 2 A) tubular shaped, extending from genito-intestinal canal to oviduct and vitelline duct. Vitelline duct (Figs 1, 2 A) Y-shaped, ventral, connecting to anterosinistral side of receptaculum seminis, bifurcating to either side near the germarium. Oötype (Figs 1, 2 A) extending from ovovitelline duct. Mehlis’ gland not observed. Uterus (Figs 1, 2 A) originating from oötype, extending anteriorly along body midline, ventral to vas deferens, to the opening of the genital atrium. Vaginal pore (Fig. 2 A) unarmed, ventral in midbody, posterior to genital atrium. Vaginal duct (Fig. 2 A) dorsal to uterus and vas deferens, arising from vaginal pore, bifurcating posterior to vaginal pore, connecting to vitelline duct. Eggs (Fig. 2 D) fusiform 180 – 375 × 55 – 155 (305 × 120, n = 3) excluding filament, with filaments at both ends broken. Vitelline follicles (Fig. 1) coextensive with intestinal branches, extending from behind genital atrium to posterior end of body, fused posterior to testes.	en	Nitta, Yusuke Kamio and Masato (2025): Redescription of Microcotyle elegans (Polyopisthocotyla: Microcotylidae) from Scombrops boops (Perciformes: Scombropidae) off Japanese Waters. Species Diversity 30 (2): 111-125, DOI: 10.12782/specdiv.30.111, URL: https://doi.org/10.12782/specdiv.30.111
A34681131A6CFFC4FF54FC6B2A272E30.taxon	materials_examined	Material examined. Twenty-two monogenean specimens from off Tatsugahama, Arita City (MPM Coll. - No. 25326), and one specimen off Minami-Ise, Mie Prefecture (MPM Coll. - No. 25327). Localities. The Seto Inland Sea off Tatsugahama, Arita City, Wakayama Prefecture, and Pacific Ocean off Minami-Ise, Mie Prefecture in Japan.	en	Nitta, Yusuke Kamio and Masato (2025): Redescription of Microcotyle elegans (Polyopisthocotyla: Microcotylidae) from Scombrops boops (Perciformes: Scombropidae) off Japanese Waters. Species Diversity 30 (2): 111-125, DOI: 10.12782/specdiv.30.111, URL: https://doi.org/10.12782/specdiv.30.111
A34681131A6CFFC4FF54FC6B2A272E30.taxon	biology_ecology	Host. Scombrops boops (Houttuyn, 1782). Site of infection. Gill filaments. Representative DNA sequences. Newly obtained cox 1 sequences (918 bp and 928 bp) from specimens collected in Arita City, Wakayama Prefecture (MPM Coll. - No. 25326) and Minami-Ise Town, Mie Prefecture (MPM Coll. - No. 25327) were deposited under DDBJ accession number LC 815758 and LC 865998, respectively. The genetic variation of cox 1 between the two specimens was 1.23 % (11 / 895 bp) with synonymous codon substitutions at the third codon position. A sequence for the partial 28 S rDNA obtained from a specimen collected in Minami-Ise Town (MPM Coll. - No. 25327) have been deposited in the DDBJ under LC 865999.	en	Nitta, Yusuke Kamio and Masato (2025): Redescription of Microcotyle elegans (Polyopisthocotyla: Microcotylidae) from Scombrops boops (Perciformes: Scombropidae) off Japanese Waters. Species Diversity 30 (2): 111-125, DOI: 10.12782/specdiv.30.111, URL: https://doi.org/10.12782/specdiv.30.111
A34681131A6CFFC4FF54FC6B2A272E30.taxon	description	Molecular data analysis. The trimmed multiple sequence alignment of cox 1 fragments consisted of 361 positions. Sequences of two microcotylids, Bivagina pagrosomi (Murray, 1931) and Polylabris halichoeres Wang and Zhang, 1998, were used as outgroups (Fig. 3). The topologies of each phylogenetic tree constructed by ML and BI analysis were almost identical, and the phylogenetic trees based on ML analysis are shown in Fig. 3. Sequences for seven species of Microcotyle formed a weakly supported clade. This clade separates into two groups: one consists of M. elegans and a clade including M. algeriensis Ayadi, Gey, Justine, and Tazerouti, 2017 and M. merche Víllora-Montero, Pérez-del-Olmo, Valmaseda-Angulo, Raga, and Montero, 2023; the other is comprised of the lineage including M. sebastis Goto, 1894 and M. pacinkar Kamio and Nitta, 2023 and one consisting of M. caudata Goto, 1894 and M. kasago Ono, Matsumoto, Nitta, and Kamio, 2020 (Fig. 3). Microcotyle elegans formed a sister lineage with the clade containing M. algeriensis and M. merche, but this relationship was not supported by either analysis.	en	Nitta, Yusuke Kamio and Masato (2025): Redescription of Microcotyle elegans (Polyopisthocotyla: Microcotylidae) from Scombrops boops (Perciformes: Scombropidae) off Japanese Waters. Species Diversity 30 (2): 111-125, DOI: 10.12782/specdiv.30.111, URL: https://doi.org/10.12782/specdiv.30.111
A34681131A6CFFC4FF54FC6B2A272E30.taxon	discussion	Remarks. The present specimens collected from S. boops in the Seto Inland Sea and Pacific Ocean conform to the descriptions and illustrations of M. elegans by Goto (1894). However, the number of the clamps is slightly larger than Goto’s description [48 – 95 in this study vs. about 50 in Goto (1894)]. Additionally, the distended receptaculum seminis between the genito-intestinal canal and the oötype was illustrated in the original description (Goto 1894), but was not observed in our specimens. Goto (1894) may have misidentified the wide, twisted oviduct on the dorsal side as distended seminal vesicle. Furthermore, our observations provided additional details about the genital atrium: it is mushroom-shaped and surrounded by radial muscle fibers. Although Goto (1894) noted the presence of conical spines in the genital atrium, the shape of the genital atrium and surrounding structures were not described in his original account.	en	Nitta, Yusuke Kamio and Masato (2025): Redescription of Microcotyle elegans (Polyopisthocotyla: Microcotylidae) from Scombrops boops (Perciformes: Scombropidae) off Japanese Waters. Species Diversity 30 (2): 111-125, DOI: 10.12782/specdiv.30.111, URL: https://doi.org/10.12782/specdiv.30.111
