taxonID	type	description	language	source
920C8790FFF4FFAFFF2DFD296AFE2ED1.taxon	diagnosis	Diagnosis (modified from Leduc 2016). Cuticle roughly annulated, sometimes ornamented with dots and longitudinal bars. Head slightly set off. Cephalic setae situated in the same circle as outer labial sensilla or in a separate circle close to the front end. Amphidial fovea unispiral, partially or completely surrounded by cuticle annulations. Buccal cavity cuticularised, with dorsal tooth, two smaller subventral teeth, and occasionally with protrusions. Pharynx with anterior peribuccal bulb and well-developed posterior oval bulb. Spicules short, arcuate, gubernaculum with dorsally or dorso – caudally apophysis. Tail short and conical.	en	Fadeeva, Natalia P., Karpova, Alena A. (2026): Three new species of Microlaimidae (Nematoda: Microlaimida) from intertidal sand of the Sea of Japan. Zootaxa 5768 (4): 479-502, DOI: 10.11646/zootaxa.5768.4.2, URL: https://doi.org/10.11646/zootaxa.5768.4.2
920C8790FFF4FFAFFF2DFD296AFE2ED1.taxon	type_taxon	Type species Bolbolaimus pellucidus Cobb, 1920	en	Fadeeva, Natalia P., Karpova, Alena A. (2026): Three new species of Microlaimidae (Nematoda: Microlaimida) from intertidal sand of the Sea of Japan. Zootaxa 5768 (4): 479-502, DOI: 10.11646/zootaxa.5768.4.2, URL: https://doi.org/10.11646/zootaxa.5768.4.2
920C8790FFF4FFAFFF2DFD296AFE2ED1.taxon	discussion	Remarks. Cobb (1920) first described the genus Bolbolaimus with B. pellucidus Cobb, 1920 as type species, and B. punctatus Cobb, 1920, but he did not provide a diagnosis for the genus. Due to the lack of a clear diagnosis, taxonomic traits were repeatedly subjected to revision. Jensen (1978) first placed Bolbolaimus within the Microlaimidae and emphasized key diagnostic traits for it: cuticularised buccal cavity, anterior peribuccal bulb, well-developed posterior oval pharyngeal bulb, excretory pore posterior to the nerve ring, copulatory apparatus in males, and outstretched ovaries in females. Later on, other characters were noted as important for differentiating Bolbolaimus from Microlaimus: relative position of outer labial sensilla and cephalic setae, cuticle annulations near of amphidial fovea, and constriction setting off the head from the rest of the body. Within the Microlaimidae, an annulated cuticle with longitudinal bars has only been described in Bolbolaimus teutonicus (Riemann, 1966) Jensen, 1978, Microlaimus annelisae Jensen, 1976, and M. ostracon Schuurmans Stekhoven, 1935. Platt & Warwick (1988), Tchesunov (2014), and Leduc (2016) have made comprehensive revisions on Bolbolaimus changing the taxonomic placement of several species described since the original description of the genus. It should be noted that many species’ descriptions are inconsistent with the diagnosis (e. g., Vincx et al. 1982, Tchesunov 2008). Subsequently, there is disagreement about which morphological traits to use for differentiating between these genera, which has resulted in changes in the placement of some species. The list of species of Bolbolaimus has been reviewed and currently 12 species are recognized as valid (Tchesunov 2014, Leduc 2016, Guo et al. 2023, Meng et al. 2025).	en	Fadeeva, Natalia P., Karpova, Alena A. (2026): Three new species of Microlaimidae (Nematoda: Microlaimida) from intertidal sand of the Sea of Japan. Zootaxa 5768 (4): 479-502, DOI: 10.11646/zootaxa.5768.4.2, URL: https://doi.org/10.11646/zootaxa.5768.4.2
920C8790FFF7FFA7FF2DFD3169F32C81.taxon	description	(Figures 2 – 6, Table 1)	en	Fadeeva, Natalia P., Karpova, Alena A. (2026): Three new species of Microlaimidae (Nematoda: Microlaimida) from intertidal sand of the Sea of Japan. Zootaxa 5768 (4): 479-502, DOI: 10.11646/zootaxa.5768.4.2, URL: https://doi.org/10.11646/zootaxa.5768.4.2
920C8790FFF7FFA7FF2DFD3169F32C81.taxon	materials_examined	Material examined. Adult male holotype (MN 210517 _ 3), 5 male paratypes (MN 210517 _ 1), and 4 female paratypes (MN 210517, MN 241010). All formalin-fixed, processed to glycerin, mounted on slides, and deposited in the nematode collection of the Division of Biological Sciences, Zoological Museum of Far Eastern Federal University, Vladivostok, Russia. Type locality. Holotype and paratypes were all collected from intertidal fine sandy sediments, 40 – 50 cm depth in Vostok Bay (42 ° 53 ' 17 " N 132 ° 43 ' 43 " E) (Figure 1), the Sea of Japan, 24 October 2010 and 21 May 2017.	en	Fadeeva, Natalia P., Karpova, Alena A. (2026): Three new species of Microlaimidae (Nematoda: Microlaimida) from intertidal sand of the Sea of Japan. Zootaxa 5768 (4): 479-502, DOI: 10.11646/zootaxa.5768.4.2, URL: https://doi.org/10.11646/zootaxa.5768.4.2
920C8790FFF7FFA7FF2DFD3169F32C81.taxon	etymology	Etymology. The species epithet is derived from the Latin “ mirandus ”, meaning “ remarkable ”.	en	Fadeeva, Natalia P., Karpova, Alena A. (2026): Three new species of Microlaimidae (Nematoda: Microlaimida) from intertidal sand of the Sea of Japan. Zootaxa 5768 (4): 479-502, DOI: 10.11646/zootaxa.5768.4.2, URL: https://doi.org/10.11646/zootaxa.5768.4.2
920C8790FFF7FFA7FF2DFD3169F32C81.taxon	description	Descriptions Males. Cylindrical slightly yellow nematodes; anterior head region set off abruptly from the body at the level of the posterior margin of the amphidial fovea and may be seen as retracted a bit into body, tail short and conical (Figures 2 and 3). Cuticle distinctly annulated (annulus width 2.0 µm) from immediately posterior to cephalic setae to near tail tip. Mouth opening broad and surrounded by six small mounts or liplets, with a short inner labial sensilla on each of them. Transversally oval amphidial fovea with cuticularised outline situated 0.15 hbd (head body diameter) from anterior and only partially surrounded by cuticular annulations. Cheilostoma short with twelve cuticularized longitudinal folds, with a short inner labial papilla on each lip; funnel-shaped oesophastoma with strong triangular dorsal tooth capable of being protruded into the cheilostoma and two less noticeable subventral teeth (Figures 2 В, 2 С, 2 D and 3 В). Six outer labial setiform sensilla and four longer cephalic setae in two circles located at the base of the oesophastoma. Pharynx cylindrical, anterior region surrounding buccal cavity, swollen into a prominent muscular oval-shaped bulb (15 % of pharynx length); posterior part of the pharynx with a well-developed oval-shaped muscular bulb (21.5 – 23.5 % of pharynx length) and having a thick cuticular lining partitioned into two sections. Cardia is poorly developed. Secretory-excretory system present; renette cell situated slightly posterior to cardia, 22 × 15 µm; excretory pore behind nerve ring and situated in the middle of the pharynx length from anterior. Reproductive system diorchic, testes opposed and outstretched. Spicules equal, short, weak, curved, distally pointed and proximally not cephalated; 2 – 3.5 cbd (cloacal body diameter) long. Gubernaculum as short, simple bar, oriented parallel to the posterior half of the spicules (Figures 2 E, 2 F and 3 C). Precloacal supplements are absent. Tail conical, with three pairs of short and stout sub-ventral setae. Three-four caudal glands and spinneret present (Figures 2 E and 3 C). Females. Similar to males in most aspects (Figures 4 – 6). Reproductive system didelphic, with opposed and outstretched genital branches, both situated ventrally relative to intestine. Vulva situated mid-body (V = 51 – 52 %), proximal portion of vagina surrounded by constrictor muscle (Figure 4 D).	en	Fadeeva, Natalia P., Karpova, Alena A. (2026): Three new species of Microlaimidae (Nematoda: Microlaimida) from intertidal sand of the Sea of Japan. Zootaxa 5768 (4): 479-502, DOI: 10.11646/zootaxa.5768.4.2, URL: https://doi.org/10.11646/zootaxa.5768.4.2
920C8790FFF7FFA7FF2DFD3169F32C81.taxon	diagnosis	Diagnosis. Bolbolaimus mirandus sp. nov. is characterised by anterior cephalic region set off from the body, large cuticularised buccal cavity with one strong dorsal tooth and two less noticeable subventral teeth, muscular anterior and posterior pharyngeal bulbs, curved and not cephalated spicules, short and simple gubernaculum, and short and conical tail. Differential diagnosis. The new species can be distinguished from the below species by a large cuticularised buccal cavity with one strong dorsal tooth. Bolbolaimus mirandus sp. nov. is most morphological similar to the group of species with two strong muscular anterior and posterior pharyngeal bulbs:	en	Fadeeva, Natalia P., Karpova, Alena A. (2026): Three new species of Microlaimidae (Nematoda: Microlaimida) from intertidal sand of the Sea of Japan. Zootaxa 5768 (4): 479-502, DOI: 10.11646/zootaxa.5768.4.2, URL: https://doi.org/10.11646/zootaxa.5768.4.2
920C8790FFF7FFA7FF2DFD3169F32C81.taxon	discussion	According to the shape of the spicules and gubernaculum, B. mirandus sp. nov. resembles B. tongaensis and B. riemanni however, it is larger in body size (1010 – 1328 µm vs 458 – 476 µm and 875 µm, respectively), and the length of spicules is longer (45 – 54 µm vs 25 µm and 20.5 µm, respectively). The new species belongs to the group of species of the genus Bolbolaimus with amphidial fovea near the anterior end: B. chitwoodi, B. crassiceps and B. punctatus but from B. chitwoodi it differs in shape of the amphidial fovea (oval amphidial aperture). The new species, in contrast to B. crassiceps, lacks numerous small denticles in the stoma, it has smaller amphidial fovea (25 – 26 % hbd vs 50 % hbd) and its spicules are longer (45 – 54 µm vs 23 – 27 µm, respectively). B. mirandus sp. nov. is similar to B. major in body length but differs in the length (c = 12 – 13.6 vs c = 10.5 – 11.3) and spicules length (45 – 54 µm vs 41 – 42 µm, respectively) and shape of gubernaculum apophysis (Table 1). The new species can most easily be differentiated from B. punctatus in shorter body (1010 – 1328 µm vs 1600 µm), in amphidial fovea size (25 – 26 % hbd vs 31 % hbd). B. mirandus sp. nov. differs from B. wieseri in longer body length (1010 – 1328 µm vs 710 – 990 µm), outer labial setae length (setiform, 6 – 8 µm in length vs papilliform), and tail length (2 – 3.5 cbd vs 2.2 – 2.3 cbd). New species differs from B. teutonicus in the size of the amphidial fovea (25 – 26 % hbd vs 50 – 60 % hbd) (Table 1).	en	Fadeeva, Natalia P., Karpova, Alena A. (2026): Three new species of Microlaimidae (Nematoda: Microlaimida) from intertidal sand of the Sea of Japan. Zootaxa 5768 (4): 479-502, DOI: 10.11646/zootaxa.5768.4.2, URL: https://doi.org/10.11646/zootaxa.5768.4.2
920C8790FFFFFFA2FF2DFB946AF92DE8.taxon	description	(Figures 7 – 10, Table 1)	en	Fadeeva, Natalia P., Karpova, Alena A. (2026): Three new species of Microlaimidae (Nematoda: Microlaimida) from intertidal sand of the Sea of Japan. Zootaxa 5768 (4): 479-502, DOI: 10.11646/zootaxa.5768.4.2, URL: https://doi.org/10.11646/zootaxa.5768.4.2
920C8790FFFFFFA2FF2DFB946AF92DE8.taxon	materials_examined	Material examined. Adult male holotype (260210 _ 2), and 8 male paratypes (MN 250508, MN 040417, MN 210517,) and 5 female paratypes (MN 250610, MN 261020; MN 190821, MN 270823 _ 7), formalin-fixed, mounted on slides, in glycerin, deposited in the nematode collections of the Division of Biological Sciences, Zoological Museum of Far Eastern Federal University, Vladivostok, Russia.	en	Fadeeva, Natalia P., Karpova, Alena A. (2026): Three new species of Microlaimidae (Nematoda: Microlaimida) from intertidal sand of the Sea of Japan. Zootaxa 5768 (4): 479-502, DOI: 10.11646/zootaxa.5768.4.2, URL: https://doi.org/10.11646/zootaxa.5768.4.2
920C8790FFFFFFA2FF2DFB946AF92DE8.taxon	type_taxon	Type locality. Holotype and paratypes were all collected from intertidal fine sandy sediments, 40 – 50 cm depth in Vostok Bay (42 ° 53 ' 17 " N 132 ° 43 ' 43 " E) (Figure 1), the Sea of Japan, from 25 May 2008 to 27 August 2023.	en	Fadeeva, Natalia P., Karpova, Alena A. (2026): Three new species of Microlaimidae (Nematoda: Microlaimida) from intertidal sand of the Sea of Japan. Zootaxa 5768 (4): 479-502, DOI: 10.11646/zootaxa.5768.4.2, URL: https://doi.org/10.11646/zootaxa.5768.4.2
920C8790FFFFFFA2FF2DFB946AF92DE8.taxon	etymology	Etymology. This species epithet is named in honor of Senior Researcher Marina S. Selina of A. V. Zhirmunsky National Scientific Centre of Marine Biology, Russia.	en	Fadeeva, Natalia P., Karpova, Alena A. (2026): Three new species of Microlaimidae (Nematoda: Microlaimida) from intertidal sand of the Sea of Japan. Zootaxa 5768 (4): 479-502, DOI: 10.11646/zootaxa.5768.4.2, URL: https://doi.org/10.11646/zootaxa.5768.4.2
920C8790FFFFFFA2FF2DFB946AF92DE8.taxon	description	Descriptions Males. Body large and cylindrical (Figures 7 A and 8 A), with faint yellow color. Head blunt, slightly set off from rest of body (Figures 7 C, 7 D and 8 B). Cuticle annulated with transverse striae immediately posterior amphids. Each ring with numerous longitudinal bars (Figures 7 G and 8 C), pores not seen by light microscopy. Six inner labial papillae and six outer labial papillae (4 – 6 µm in length) in two separate circles; four cephalic setae situated further posteriorly at mid-level of amphidial fovea, 0.4 corresponding body diameter (hbd) long, situated at the level of dorsal tooth. Four setae at posterior end bulbus present. Cryptocircular amphideal fovea ovalcircular shaped, unispiral and oval shaped, 7 – 8 μm in height and 7 – 10 μm in diameter situated 0.3 hbd from anterior and only partially surrounded by cuticule annulations. Cheilostoma short with 12 cuticularized longitudinal folds, 2 – 4 µm in depth. Esophastoma strongly sclerotized; armed with one large dorsal tooth (2 µm), two subventral teeth (one tooth opposite the dorsal one and one tooth lies at the base), posterior part as a complicated compartments, with small denticles. Pharynx cylindrical, anterior region surrounding pharyngostoma swollen into a bulb, (10 – 15 % of pharynx length), posterior region muscular and swollen into an oval-shaped prominent bulb (21 – 24 % of pharynx length). Nerve ring located posterior to middle pharynx region (52.1 – 56.8 % of pharynx length). Secretory-excretory system present; renette cell situated slightly posterior to pharynx bulb, excretory pore located posterior to the nerve ring (Figure 8 B). Cardia elongated triangular. Tail conical, 2.9 – 4 cbd long, with pairs of subventral caudal setae. Cell bodies of caudal glands restricted to caudal region, difficult to observe in most specimens. Reproductive system diorchic, testes opposed and outstretched. Sperm cells elongated large (8 × 10 µm). Two equal spicules, 44 – 59 µm long, scythe-shaped, circularized, with narrow proximal end and pointed distal end. Gubernaculum bent towards the extremities with pronounced hook proximally, 22 – 31 μm (Figures 7 F and 8 E). Females. Resembling male in most features (Figures 9 A and 10 A), however, differs in the following features: cephalic setae 0.3 (hbd) long, shorter, amphidial fovea circular shaped (Figures 9 D and 10 B). Reproductive system didelphic, with opposed and outstretched ovaries. Anterior ovary to left of intestine and posterior ovary to right of intestine. Vulva closer to the anterior end (V = 46.8 – 49.3 %).	en	Fadeeva, Natalia P., Karpova, Alena A. (2026): Three new species of Microlaimidae (Nematoda: Microlaimida) from intertidal sand of the Sea of Japan. Zootaxa 5768 (4): 479-502, DOI: 10.11646/zootaxa.5768.4.2, URL: https://doi.org/10.11646/zootaxa.5768.4.2
920C8790FFFFFFA2FF2DFB946AF92DE8.taxon	diagnosis	Diagnosis. Bolbolaimus selinae sp. nov. is characterized by body length 1299 – 1543 μm, head slightly set off from rest of the body, cephalic setae, 0.3 – 0.4 corresponding body diameter long; cuticular annuli strongly pronounced, with very close and fine longitudinal bars; lateral differentiation absent; pharynx with anterior and posterior bulb; large buccal cavity with one large dorsal tooth, two small subventral teeth, and transversal rows of denticles with prominent anterior pharynx bulb; amphidial fovea oval shaped in males and circular shaped in females; arcuate spicules with curved proximal dorso-caudal gubernaculur apohysis, 1.1 cloacal body diameter long, conical tail 3 – 4 cloacal body diameter long in males and 4 – 5 cloacal body diameter long in females. Differential diagnosis. Bolbolaimus selinae sp. nov. belongs to the group of species with a ringed cuticle ornamented with longitudinal striation and prominent anterior pharynx bulb:	en	Fadeeva, Natalia P., Karpova, Alena A. (2026): Three new species of Microlaimidae (Nematoda: Microlaimida) from intertidal sand of the Sea of Japan. Zootaxa 5768 (4): 479-502, DOI: 10.11646/zootaxa.5768.4.2, URL: https://doi.org/10.11646/zootaxa.5768.4.2
920C8790FFFFFFA2FF2DFB946AF92DE8.taxon	discussion	Bolbolaimus selinae sp. nov. differs from B. punctatus by amphidial fovea oval shaped in males and circular shaped in females, body length (1299 – 1543 µm vs 1600 µm). The new species can most easily be differentiated from B. riemanni in longer body (1299 – 1543 µm vs 875 µm), in amphidial fovea size (32 – 35 % hbd vs 50 % hbd), cephalic setae length (7 – 15 µm vs 6.3 µm) and spicules shape and length (44 – 59 µm vs 20.5 µm). B. selinae sp. nov. can be differentiated from B. teutonicus and B. tongaensis by spicules length (44 – 59 µm vs 27 – 28 µm and 25 µm accordingly) and gubernaculum shape (curved proximal dorso-caudal apohysis vs short and straight), and longer tail (111 – 125 µm vs 91 – 95 µm and 60 – 68 µm accordingly). Bolbolaimus selinae sp. nov. most resembles Bolbolaimus major with similar morphometric characteristics but differs in cuticle annulated with faint longitudinal bars, longer tail and spicules, and the position of the amphidial fovea closer to the anterior end (8 – 9 µm vs 10 – 15 µm).	en	Fadeeva, Natalia P., Karpova, Alena A. (2026): Three new species of Microlaimidae (Nematoda: Microlaimida) from intertidal sand of the Sea of Japan. Zootaxa 5768 (4): 479-502, DOI: 10.11646/zootaxa.5768.4.2, URL: https://doi.org/10.11646/zootaxa.5768.4.2
920C8790FFFAFFA2FF2DFD61691028B8.taxon	diagnosis	Diagnosis (modified from Lima et al. (2022) and Manoel et al. (2024 )). Cuticle transversely striated, sometimes ornamented with punctuations or longitudinal bars, lateral alae may be present. Hypodermal glands with pores or setae are well developed. Head slightly set off. Six inner labial setae, usually papilliform; six outer labial setae, papilliform or setiform, and four cephalic setae. Amphidial fovea cryptocircular or unispiral (cryptospiral). Presence or absence of sexual dimorphism in amphidial fovea size. Buccal cavity small to medium-sized, with two to five (three teeth in most species) small or well-developed teeth. Pharynx with only well-developed posterior oval bulb. Two opposite testes, seldom one anterior. Pre-cloacal supplements absent or present (papilliform, tubular, or small pores). Spicules usually short and arcuate, seldom long and slender, often bent distally but without dorso-caudal apophyses. Gubernaculum usually present, without dorso-caudal apophysis. Female reproductive system didelphicamphidelphic, with outstretched ovaries. Tail predominantly conical.	en	Fadeeva, Natalia P., Karpova, Alena A. (2026): Three new species of Microlaimidae (Nematoda: Microlaimida) from intertidal sand of the Sea of Japan. Zootaxa 5768 (4): 479-502, DOI: 10.11646/zootaxa.5768.4.2, URL: https://doi.org/10.11646/zootaxa.5768.4.2
920C8790FFFAFFA2FF2DFD61691028B8.taxon	discussion	Remarks. The morphological differences between Microlaimus and Bolbolaimus remain subtle, primarily based on head and pharyngeal morphology. Species with head not set off and with prominent posterior circular bulb should be kept in Microlaimus, and with oval bulb in Bolbolaimus. The percentage occupied by the posterior oval bulb may also be informative. Nowadays, the genus includes 89 valid species (Nemys eds., 2025). The species within the genus Microlaimus can be divi	en	Fadeeva, Natalia P., Karpova, Alena A. (2026): Three new species of Microlaimidae (Nematoda: Microlaimida) from intertidal sand of the Sea of Japan. Zootaxa 5768 (4): 479-502, DOI: 10.11646/zootaxa.5768.4.2, URL: https://doi.org/10.11646/zootaxa.5768.4.2
920C8790FFFAFFB8FF2DFE5C69C42A15.taxon	description	(Figures 11 – 14, Table 1)	en	Fadeeva, Natalia P., Karpova, Alena A. (2026): Three new species of Microlaimidae (Nematoda: Microlaimida) from intertidal sand of the Sea of Japan. Zootaxa 5768 (4): 479-502, DOI: 10.11646/zootaxa.5768.4.2, URL: https://doi.org/10.11646/zootaxa.5768.4.2
920C8790FFFAFFB8FF2DFE5C69C42A15.taxon	materials_examined	Material examined. Adult male holotype and 2 male paratypes (MN 190823 _ 53) and 5 male paratypes (MN 190823 _ 32), 1 female paratype (MN 190823 _ 33), formalin-fixed, mounted on slides, in glycerin, deposited in the nematode collections of the Division of Biological Sciences, Zoological Museum of Far Eastern Federal University, Vladivostok, Russia. Type locality. Holotype and paratypes were all collected from intertidal fine sandy sediments, 40 – 50 cm depth in the Pogranichnaya Bay of Popov Island (42 ° 57 ' 05 " N 131 ° 44 ' 23 " E) (Figure 1), the Sea of Japan, 19 August 2023. Additional locality. Two males and four females paratypes (MN 130722 _ 3) intertidal fine sand 0.50 depth, sandbar Nazimova (42 ° 37 ' 21 " N, 130 ° 47 ' 20 " E) (Figure 1), Primorsky Krai, the Sea of Japan, 13 July 2022.	en	Fadeeva, Natalia P., Karpova, Alena A. (2026): Three new species of Microlaimidae (Nematoda: Microlaimida) from intertidal sand of the Sea of Japan. Zootaxa 5768 (4): 479-502, DOI: 10.11646/zootaxa.5768.4.2, URL: https://doi.org/10.11646/zootaxa.5768.4.2
920C8790FFFAFFB8FF2DFE5C69C42A15.taxon	etymology	Etymology. The specific epithet “ asiaticus ” refers to the Asiatic coast of the Sea of Japan, where the species was collected.	en	Fadeeva, Natalia P., Karpova, Alena A. (2026): Three new species of Microlaimidae (Nematoda: Microlaimida) from intertidal sand of the Sea of Japan. Zootaxa 5768 (4): 479-502, DOI: 10.11646/zootaxa.5768.4.2, URL: https://doi.org/10.11646/zootaxa.5768.4.2
920C8790FFFAFFB8FF2DFE5C69C42A15.taxon	description	Descriptions Males. Body brownish, long, cylindrical, tapering to both ends (Figures 11 A and 12 A). Head smooth, swollen, weakly off set from body. Cuticle striated from insertion of cephalic setae. Lateral alae and hypodermal glands are not observed. Six internal labial papillae and six external papillae present (7 μm). Four cephalic setae, 12 – 14 μm long. Monospiral amphidial fovea turning ventrally, 33 – 42 % hbd wide, situated at the level of posterior part of stoma (Figures 11 D and 12 B). Cheilostoma short (4 × 5 μm) with twelve circularized longitudinal folds, oesophastoma cup-shaped, not compartmentalised, strongly sclerotised with weakly conspicuous dorsal tooth and two small subventral processes (Figures 11 C and 12 B). Pharynx swollen around buccal cavity, posteriorly dilated into small circular pharyngeal bulb (23 – 29 × 18 – 20 μm) (Figure 11 B). Excretory pore opening from anterior end posterior to nerve ring (81 – 87 μm). Large oval ventral gland posterior to pharyngeal bulb. Tail conical, 3.9 – 4.2 cbd long, with four pairs of sub-ventral caudal setae and two terminal setae (Figures 11 E and 12 C). Cell bodies of caudal glands restricted to caudal region, difficult to observe in most specimens. Spinneret well developed. Reproductive system diorchic, testes opposed and outstretched. Sperm cells elongated. Two equal spicules, 36 – 56 μm long, scythe-shaped, strongly sclerotised, with narrow proximal end and pointed distal end. Gubernaculum apparently surrounding spicules, with dorsally directed curved apophyses, 18 – 26 μm. One small setae anterior to cloacal opening and four small tubular pre-cloacal supplements. Two sublateral setae located ca 1.5 cbd anterior to cloacal opening (Figure 12 C). Spinneret was not observed. Females. Similar to males in most aspects (Figures 13 A and 14 A). Reproductive system didelphic, with opposed and outstretched genital branches both situated ventrally relative to intestine. Anterior genital branch 210 – 255 μm long, posterior genital branch 255 – 340 μm long. Vulva situated posterior to mid-body 61 – 64 %. Vagina with thick walls perpendicular to the longitudinal body axis (Figure 13 E). Diameter of the large oocyte 13 × 41 μm in female. Vulval glands present, two different types anterior and posterior to the vagina.	en	Fadeeva, Natalia P., Karpova, Alena A. (2026): Three new species of Microlaimidae (Nematoda: Microlaimida) from intertidal sand of the Sea of Japan. Zootaxa 5768 (4): 479-502, DOI: 10.11646/zootaxa.5768.4.2, URL: https://doi.org/10.11646/zootaxa.5768.4.2
920C8790FFFAFFB8FF2DFE5C69C42A15.taxon	diagnosis	Diagnosis. Microlaimus asiaticus sp. nov. is characterised by a combination of having monospiral amphidial fovea turning ventrally, 33 – 42 % hbd wide, situated at the level of posterior part of stoma; stoma cup-shaped, not compartmentalized, strongly sclerotized with weakly conspicuous dorsal tooth and two small subventral protrusions; pharynx swollen around buccal cavity, posteriorly dilated into small circular pharyngeal bulb; tail conical and males with four conical precloacal supplements (Figures 11 E and 12 C). Differential diagnosis. The species within the genus Microlaimus can be divided into two groups based on the presence or absence, in the males, of preanal supplements. Microlaimus asiaticus sp. nov. belongs to the group of species with supplements. The occurrence of pre-cloacal papilliform, tubular, or small pore-like supplements has also been reported for 26 of the species of the genus Microlaimus. M. asiaticus sp. nov. by morphometric characters (in terms of total body length, size of the amphidial fovea) belongs to the group of species:	en	Fadeeva, Natalia P., Karpova, Alena A. (2026): Three new species of Microlaimidae (Nematoda: Microlaimida) from intertidal sand of the Sea of Japan. Zootaxa 5768 (4): 479-502, DOI: 10.11646/zootaxa.5768.4.2, URL: https://doi.org/10.11646/zootaxa.5768.4.2
920C8790FFFAFFB8FF2DFE5C69C42A15.taxon	discussion	The new species, in contrast to M. conothelis, does not have numerous small denticles in the stoma, it is shorter in tail length, but the spicules are longer (36 – 56 μm vs 28 – 32 μm, respectively). M. paraconothelis differs from new species in the thicker body in males (a = 27 – 30.6 vs 45.8 – 63.4, respectively), considerably longer spicules (70 – 77 µm vs 36 – 56 μm), structure and number of supplements (12 supplements in the form of canals in precloacal thickened medioventral cuticle, while new species has 3 – 4 conical preanal supplements); the distance from the amphidial fovea to the anterior end (12 – 16 µm vs 6 – 8 µm). M. asiaticus sp. nov. differs from M. sergeevae in the longer spicules 36 – 56 μm (1.6 cbd) vs 34 – 37 μm (1.1 – 1.4 cbd) and shape of the gubernaculum (with apophysis dorso – caudally directed with anterior pointed hook vs gubernacular apophyses surrounding distal end of spicules); the distance from the amphidial fovea to the anterior end (12 – 16 µm vs 6 – 8 µm). The new species resembles M. bathyalis (Kovalev & Miljutina, 2009) Tchesunov, 2014 in the shape and number of small papilliform medioventral supplements but it differs in the longer body (1404 – 1860 µm vs 378 – 478 μm, respectively) and spicules length (35.6 – 55.9 μm vs 16 – 19 μm, respectively).	en	Fadeeva, Natalia P., Karpova, Alena A. (2026): Three new species of Microlaimidae (Nematoda: Microlaimida) from intertidal sand of the Sea of Japan. Zootaxa 5768 (4): 479-502, DOI: 10.11646/zootaxa.5768.4.2, URL: https://doi.org/10.11646/zootaxa.5768.4.2
