taxonID	type	description	language	source
450F89263061FFE8F8EC8BDAEE993EEF.taxon	description	(Figs 1 – 4)	en	Oya, Yuki, Hookabe, Natsumi, Jimi, Naoto, Furushima, Yasuo, Fujiwara, Yoshihiro (2025): Description of a new bathyal species of Notocomplana (Platyhelminthes, Polycladida) collected from Bathymodiolus aggregations in a deep-sea hydrocarbon seep. Zootaxa 5722 (2): 265-277, DOI: 10.11646/zootaxa.5722.2.6, URL: https://doi.org/10.11646/zootaxa.5722.2.6
450F89263061FFE8F8EC8BDAEE993EEF.taxon	etymology	Etymology. The new specific name profunda (- us, - a, - um) is a Latin adjective meaning ‘ deep’ and refers to the habitat of the flatworms. The new Japanese name for the new species is derived from shinkai (deep sea) and usuhiramushi (Notocomplana polyclad) in the Japanese language.	en	Oya, Yuki, Hookabe, Natsumi, Jimi, Naoto, Furushima, Yasuo, Fujiwara, Yoshihiro (2025): Description of a new bathyal species of Notocomplana (Platyhelminthes, Polycladida) collected from Bathymodiolus aggregations in a deep-sea hydrocarbon seep. Zootaxa 5722 (2): 265-277, DOI: 10.11646/zootaxa.5722.2.6, URL: https://doi.org/10.11646/zootaxa.5722.2.6
450F89263061FFE8F8EC8BDAEE993EEF.taxon	diagnosis	Diagnosis. Notocomplana without tentacles, eyespots, and color pattern on dorsal surface of body. Copulatory apparatus consisting of tripartite-like seminal vesicle, prostatic vesicle smaller than seminal vesicle, and long, tubular Lang’s vesicle (Figs 1 – 4).	en	Oya, Yuki, Hookabe, Natsumi, Jimi, Naoto, Furushima, Yasuo, Fujiwara, Yoshihiro (2025): Description of a new bathyal species of Notocomplana (Platyhelminthes, Polycladida) collected from Bathymodiolus aggregations in a deep-sea hydrocarbon seep. Zootaxa 5722 (2): 265-277, DOI: 10.11646/zootaxa.5722.2.6, URL: https://doi.org/10.11646/zootaxa.5722.2.6
450F89263061FFE8F8EC8BDAEE993EEF.taxon	materials_examined	Material examined. Holotype: NSMT-Pl- 9511, 911 m depth, off Hatsushima, Shizuoka Prefecture, Japan, 24 October 2021, coll. N. Hookabe and N. Jimi, sagittal sections of whole body on 37 slides, MT stain. Paratypes: NSMT-Pl- 9512, ibid., sagittal sections of anterior 1 / 3 of body on 19 slides and posterior 2 / 3 of body containing pharynx and copulatory apparatus on 33 slides, HE stain; NSMT-Pl- 9513, ibid., whole mount of anterior 1 / 3 of body and cross sections of posterior 2 / 3 of body containing pharynx and copulatory apparatus on 27 slides, HE stain; NSMT-Pl- 9514, whole mount of body; NSMT-Pl- 9515, whole body fixed and preserved in 99.5 % ethanol. Sequenced material. Paratype: NSMT-Pl- 9515.	en	Oya, Yuki, Hookabe, Natsumi, Jimi, Naoto, Furushima, Yasuo, Fujiwara, Yoshihiro (2025): Description of a new bathyal species of Notocomplana (Platyhelminthes, Polycladida) collected from Bathymodiolus aggregations in a deep-sea hydrocarbon seep. Zootaxa 5722 (2): 265-277, DOI: 10.11646/zootaxa.5722.2.6, URL: https://doi.org/10.11646/zootaxa.5722.2.6
450F89263061FFE8F8EC8BDAEE993EEF.taxon	description	Description. Living worms elongated oval (Fig. 1 A, B). Body whitish translucent, no color pattern (Fig. 1 A). Intestine not anastomosed, spreading throughout body except into the margins. Pharynx, sperm ducts and seminal vesicle visible whitish through ventral body wall (Fig. 1 B). Fixed specimens 13 – 19 mm in length (19 mm in holotype), 6.6 – 9.7 mm in maximum width (9.7 mm in holotype) (Fig. 2 A, B). Pharynx ruffled, about one-fourth of body length (3.1 – 4.5 mm in length, 4.5 mm in holotype), located at slightly anterior to center of body (Fig. 2 B). Mouth opening at center of pharyngeal cavity. Male and female gonopores separate; male gonopore opening at about two-fifths to one-half of body length (5.4 – 8.9 mm, 8.9 mm in holotype) from posterior end; female gonopore situated 0.6 – 1.2 mm (1.1 mm in holotype) posterior to male gonopore (Fig. 2 B). Tentacles and eyespots absent (Fig. 2 A, C). Male copulatory apparatus located immediately posterior to pharynx (Fig. 2 D), consisting of seminal vesicle, interpolated prostatic vesicle, and penis papilla (Figs 3, 4 A). Pair of sperm ducts running anteriorly from posterior to female gonopore, turning medially at about one-half length of pharynx, subsequently running posteriorly along both sides of pharynx to short distance beyond posterior end of pharynx, then turning anteriorly (Fig. 1 B) to open separately to seminal vesicle; common sperm duct lacking (Fig. 3 B – D). Seminal vesicle nearly tripartite-type, with 35 – 176 µm (25 – 176 µm in holotype) thick muscular wall formed by intermingle fibers (Figs 2 D, 3, 4 A). Distal end of seminal vesicle forming intra-prostatic ejaculatory duct of 187 – 213 μm in length (213 μm in holotype) that projecting deeply into prostatic vesicle. Prostatic vesicle bulbiform in shape, 311 – 360 μm on long axis (360 μm in holotype), 295 – 345 μm on short axis (345 μm in holotype), with 41 – 113 µm (46 – 113 µm in holotype) thick muscular wall (Figs 3 A, 4 A). Inner lining of prostatic vesicle glandular, forming six tubular chambers surrounding intra-prostatic ejaculatory duct (Fig. 4 B – E). Post-prostatic ejaculatory duct lined with glandular epithelium similar to that of prostatic vesicle and surrounded by circular muscles (Fig. 4 A, E). Penis papilla conical in shape, not sclerotized. Male atrium cone-shaped, lined with ciliated epithelium, lacking penis sheath. Pair of oviducts forming common oviduct, latter running antero-dorsally to enter vagina (Figs 3 A, 4 E). Lang’s vesicle duct 693 – 737 µm in length (737 µm in holotype), lined with folded ciliated epithelium (Fig. 4 F). Lang’s vesicle tubular in shape, 1540 – 1650 µm in length (1650 µm in holotype), lined with columnar cells (Fig. 4 F). Lang’s vesicle duct and Lang’s vesicle surrounded by thin muscular wall. Vagina 1450 – 1697 µm in length (1697 µm in holotype), surrounded by circular muscle fibers and lined with ciliated epithelium, running anteriorly, then turning posteriorly to exit at female gonopore. About two-thirds to one-fourth of vagina surrounded by cement glands (Fig. 4 F). Vagina bulbosa not developed.	en	Oya, Yuki, Hookabe, Natsumi, Jimi, Naoto, Furushima, Yasuo, Fujiwara, Yoshihiro (2025): Description of a new bathyal species of Notocomplana (Platyhelminthes, Polycladida) collected from Bathymodiolus aggregations in a deep-sea hydrocarbon seep. Zootaxa 5722 (2): 265-277, DOI: 10.11646/zootaxa.5722.2.6, URL: https://doi.org/10.11646/zootaxa.5722.2.6
450F89263061FFE8F8EC8BDAEE993EEF.taxon	materials_examined	Type locality. 911 m depth, off Hatsushima (35 ° 00.94 ʹN, 139 ° 13.38 ʹE), Sagami Bay, Shizuoka Prefecture, Japan. Habitat. Mussel beds of Bathymodiolus species. Other invertebrates such as polychaetes, nemerteans, sea spiders, and acoels were also found in the habitat (Hookabe et al. 2024). Molecular phylogeny. Notocomplana profunda sp. nov. is nested in a robust clade (97 in bootstrap value (BS) / 1.00 in posterior probability (PP )) formed by Notoplana atomata (Müller, 1776) and five Notocomplana species: N. hagiyai Oya & Kajihara, 2017, N. humilis (Stimpson, 1857), N. japonica (Kato, 1937), N. koreana (Kato, 1937), and N. septentrionalis (Kato, 1937) (Fig. 5). Here, we call this clade “ humilis clade ” named after the clade containing N. humilis, the type species of Notocomplana. In this clade, the present species is the sister to Notoplana atomata with a 99 % BS in the ML tree and 1.00 PP in the BI tree.	en	Oya, Yuki, Hookabe, Natsumi, Jimi, Naoto, Furushima, Yasuo, Fujiwara, Yoshihiro (2025): Description of a new bathyal species of Notocomplana (Platyhelminthes, Polycladida) collected from Bathymodiolus aggregations in a deep-sea hydrocarbon seep. Zootaxa 5722 (2): 265-277, DOI: 10.11646/zootaxa.5722.2.6, URL: https://doi.org/10.11646/zootaxa.5722.2.6
450F89263061FFE8F8EC8BDAEE993EEF.taxon	discussion	Remarks. The present polyclads are characterized by possessing i) a seminal vesicle, ii) an interpolated prostatic vesicle with an intra-prostatic ejaculatory duct, iii) several tubular chambers in the prostatic vesicle, iv) a conical penis papilla lacking a penis stylet, v) a Lang’s vesicle, and vi) separated gonopores. The morphology of the species meets the diagnosis of Notocomplana (cf. Faubel 1983; Litvaitis et al. 2019). Our molecular phylogenetic analyses demonstrated that the present species is the sister to a notoplanid species, Notoplana atomata, with high nodal supports; however, the morphology of the species is clearly distinguished from that of Notoplana atomata as mentioned later. In addition, both Notocomplana and Notoplana are not monophyletic (Fig. 5). Here, we assigned the present species to Notocomplana based on the morphological criteria. The copulatory apparatus of the newly described species Notocomplana profunda sp. nov. is characterized by the presence of a prostatic vesicle smaller than the seminal vesicle and a tubular elongated Lang’s vesicle as well as the absence of a common sperm duct (Figs 2 D, 3, 4). Among the 33 valid species of Notocomplana (López-Márquez et al. 2025), the same combination of characters is only observed in N. sanguinea (Freeman, 1933). However, N. profunda sp. nov. is distinguished from N. sanguinea by i) the absence of eyespots (present in N. sanguinea), ii) the absence of color patterns on the body surface (a red saddle across the central part of the dorsal surface in N. sanguinea), iii) the length of the pharynx relative to the body length (one-fourth in N. profunda sp. nov.; two-fifths in N. sanguinea), iv) the shape of the seminal vesicle (nearly tripartite shaped in N. profunda sp. nov.; bean-shaped in N. sanguinea), and v) the presence / absence of a tooth-like elevation in the vagina (absent in N. profunda sp. nov.; present in N. sanguinea) (Freeman 1933, pl. XV, figs 11 – 13; Hyman 1953, figs 81 – 83).	en	Oya, Yuki, Hookabe, Natsumi, Jimi, Naoto, Furushima, Yasuo, Fujiwara, Yoshihiro (2025): Description of a new bathyal species of Notocomplana (Platyhelminthes, Polycladida) collected from Bathymodiolus aggregations in a deep-sea hydrocarbon seep. Zootaxa 5722 (2): 265-277, DOI: 10.11646/zootaxa.5722.2.6, URL: https://doi.org/10.11646/zootaxa.5722.2.6
