taxonID	type	description	language	source
F04E9478FFD3FFD37BF7FD44FF1D2051.taxon	diagnosis	Diagnosis. Large-sized dicyemid; body length to 1.0 mm. Calotte conical, rounded anteriorly. Vermiform stages with 33 – 35 peripheral cells: 4 propolars + 5 metapolars + 2 parapolars + 22 – 24 trunk cells. Infusoriform embryos with 39 cells; refringent bodies liquid; and 2 nuclei present in each urn cell.	en	Furuya, Hidetaka (2025): Two New Species of Dicyemids (Phylum Dicyemida) from Octopus conispadiceus (Mollusca: Cephalopoda: Octopoda) in Japanese Waters. Species Diversity 30 (2): 135-145, DOI: 10.12782/specdiv.30.135, URL: https://doi.org/10.12782/specdiv.30.135
F04E9478FFD3FFD37BF7FD44FF1D2051.taxon	description	Description. Nematogens (n = 20) (Figs 1 a, c, d, 2 a, c, d). Body length 3400 – 10200 µm and width 120 – 210 µm, widest in region of metapolars; trunk width mostly uniform. Peripheral cell number 33 (Table 2): 4 propolars + 5 metapolars + 2 parapolars + 20 – 22 diapolars + 2 uropolars. Calotte conical, rounded anteriorly; cilia on calotte about 4 µm long, oriented anteriorly. Propolar cells and their nuclei smaller than metapolar cells and their nuclei. Propolar cells occupy anterior 35 % – 40 % of calotte length when viewed laterally (Figs 1 c, 2 c, d). Cytoplasm of propolar and metapolar cells more darkly stained by hematoxylin than cytoplasm of other peripheral cells. Verruciform cell absent in peripheral cells. Axial cell cylindrical, rounded anteriorly and extending forward to base of metapolar cells (Figs 1 c, 2 d). About 20 vermiform embryos present in an axial cell of large individuals. Agametes occasionally fusiform in shape (Fig. 1 d). Vermiform embryos (n = 20) (Figs 1 e, 2 e, f). Full-grown vermiform embryo length 190 – 340 µm, width 20 – 32 µm. Peripheral cell number 33 – 35 (Table 2); trunk cells arranged in opposed pairs. Anterior end of calotte bluntly pointed. Axial cell rounded anteriorly, extending to base of propolar cells; nucleus usually located in middle of axial cell. Anterior abortive axial cell present (Figs 1 e, 2 f). Axial cell of full-grown embryos often with up to 8 agametes. Rhombogens (n = 20) (Figs 1 b, f, 2 b, g). Body similar in length to nematogens, length 3700 – 10600 µm, width 120 – 210 µm. Peripheral cell number typically 33 – 35 (Table 2). Calotte conical, rounded anteriorly. Verruciform cell absent. Axial cell shape and anterior extent similar to nematogens. One to 9 infusorigens present in axial cell of each parent individual. About 180 infusoriform embryos present per axial cell of large individuals. Accessory nuclei occasionally present in trunk cells. Infusorigens (n = 20) (Figs 1 g, 2 h). Mature infusorigens large in size, composed of 30 – 105 (mode 67) external cells (oogonia and primary oocytes) + 13 – 93 (mode 26) internal cells (spermatogonia, primary spermatocytes, and secondary spermatocytes) + 4 – 122 (mode 14) spermatozoa. Mean diameter of fertilized eggs and spermatozoa 13.2 µm and 3.0 µm, respectively. Axial cell round or ovoid, diameter 23 – 84 µm. Infusoriform embryos (n = 40) (Figs 1 h, i, 2 i – k;). Full-grown embryos large, length 32.2 ± 3.7 µm (mean ± SD, excluding cilia); length – width – height ratio 1.0: 0.80: 0.76; shape ovoid, bluntly rounded to pointed posteriorly; cilia at posterior end 8 µm long. Refringent bodies present, solid, occupying anterior 35 % of embryo length when viewed laterally (Figs 1 i, 2 k). Cilia projecting from ventral internal cells into urn cavity (Fig. 2 k). Capsule cells containing large granules (Fig. 2 k). Mature embryos with 39 cells: 35 somatic + 4 germinal cells. Somatic cells of several types present: external cells covering a large part of anterior and lateral surfaces of embryo (2 enveloping cells); external cells with cilia on external surfaces (2 paired dorsal cells + 1 median dorsal cell + 2 dorsal caudal cells + 2 lateral caudal cells + 1 ventral caudal cell + 2 lateral cells + 2 posteroventral lateral cells); external cells with refringent bodies (2 apical cells); external cells without cilia (1 couvercle cell + 2 anterior lateral cells + 2 first ventral cells + 2 second ventral cells + 2 third ventral cells); internal cells with cilia (2 ventral internal cells); and internal cells without cilia (2 dorsal internal cells + 2 capsule cells + 4 urn cells). Each urn cell containing germinal cell and 2 nuclei (Fig. 2 k). All somatic nuclei pycnotic in mature infusoriform embryos.	en	Furuya, Hidetaka (2025): Two New Species of Dicyemids (Phylum Dicyemida) from Octopus conispadiceus (Mollusca: Cephalopoda: Octopoda) in Japanese Waters. Species Diversity 30 (2): 135-145, DOI: 10.12782/specdiv.30.135, URL: https://doi.org/10.12782/specdiv.30.135
F04E9478FFD3FFD37BF7FD44FF1D2051.taxon	discussion	Remarks. Dicyemennea tsunekii sp. nov. is the first species of the genus described from O. conispadiceus and is very similar to D. californica McConnaughey, 1941, D. granularis McConnaughey, 1949, D. mcconnaugheyi Furuya, 2018, and D. nouveli McConnaughey, 1959, in peripheral cell numbers, the calotte shape of vermiform stages, and the cellular constitution and cell number of infusoriform embryos (McConnaughey 1941, 1949, 1959; Furuya et al. 2004; Furuya 2007, 2008, 2018). The accumulation of eosinophilic granules within diapolar cells, forming verruciform cells, is characteristic of D. granularis and D. mcconnaugheyi (McConnaughey 1949; Furuya 2018). In this feature, D. tsunekii sp. nov. can be distinguished from these latter two species because it does not accumulate conspicuous granules or form verruciform cells. In other characteristics, D. tsunekii sp. nov. differs from D. granularis in the length of infusoriform embryos (nearly 32 µm vs. 35 µm) and maximum agamete number of vermiform embryos (8 vs. 2) (McConnaughey 1949). It can also be distinguished from D. mcconnaugheyi in the number of infusorigens (9 vs. 3 rarely 6) and maximum number of agamete of vermiform embryos (8 vs. 6) (Furuya 2018). Dicyemennea californica shares the most characters with D. granularis except for the absent of granules in diapolar cells, thus D. tsunekii sp. nov. is also distinguishable from D. californica in the length of infusoriform embryos (nearly 32 µm vs. 35 µm) and maximum agamete number of vermiform embryos (8 vs. 2) (McConnaughey 1941).	en	Furuya, Hidetaka (2025): Two New Species of Dicyemids (Phylum Dicyemida) from Octopus conispadiceus (Mollusca: Cephalopoda: Octopoda) in Japanese Waters. Species Diversity 30 (2): 135-145, DOI: 10.12782/specdiv.30.135, URL: https://doi.org/10.12782/specdiv.30.135
F04E9478FFD3FFD37BF7FD44FF1D2051.taxon	etymology	Etymology. The specific name “ tsunekii ” is in honor of Dr. Kazuhiko Tsuneki who opened the door to biology for the author. Taxonomic summary. Type material. A syntype slide (NSMT-Me- 72) collected on 9 April 2019; additional syntypes on slide series No. OC 3970 (5 slides) in the author’s collection. Type locality. Off Shiranuka (42 ° 54 ′ N, 144 ° 12 ′ E), Hokkaido, Japan, depth 100 m. Other material examined. Slide series Nos OC 3956, 3959 (each 5 slide) collected off Shiranuka, depth 100 m, 26 February 2019 in the author’s collection. Host. Symbiotype, Octopus conispadiceus (Sasaki, 1917) (Mollusca: Cephalopoda: Octopoda), male (mature), 115 mm ML (NSMT-Mo- 85945). Site of attachment. Anterior ends (calottes) inserted into crypts of the renal appendages within the renal sacs. Prevalence. Found in 10 of 47 host specimens examined (21.3 %).	en	Furuya, Hidetaka (2025): Two New Species of Dicyemids (Phylum Dicyemida) from Octopus conispadiceus (Mollusca: Cephalopoda: Octopoda) in Japanese Waters. Species Diversity 30 (2): 135-145, DOI: 10.12782/specdiv.30.135, URL: https://doi.org/10.12782/specdiv.30.135
F04E9478FFD4FFDE7B96FF2CFF1D2B04.taxon	diagnosis	Diagnosis. Medium-sized dicyemid; body length to 2500 µm. Calotte cap-shaped. Vermiform stages with 24 peripheral cells: 4 propolars + 6 metapolars + 4 parapolars + 10 trunk cells. Infusoriform embryos with 35 cells; refringent bodies liquid; and 2 nuclei present in each urn cell.	en	Furuya, Hidetaka (2025): Two New Species of Dicyemids (Phylum Dicyemida) from Octopus conispadiceus (Mollusca: Cephalopoda: Octopoda) in Japanese Waters. Species Diversity 30 (2): 135-145, DOI: 10.12782/specdiv.30.135, URL: https://doi.org/10.12782/specdiv.30.135
F04E9478FFD4FFDE7B96FF2CFF1D2B04.taxon	description	Description. Nematogens (n = 20) (Figs 3 a, b, e, f, 4 a, c, d). Body length 800 – 2500 µm, width 90 – 240 µm, widest in region of metapolars; trunk width mostly uniform. Peripheral cell number 24 (Table 2): 4 propolars + 6 metapolars + 4 parapolars + 8 diapolars + 2 uropolars. Calotte cap-shaped, round anteriorly; cilia on calotte about 4 µm long, oriented anteriorly. Propolar cells and their nuclei smaller than metapolar cells and their nuclei. Propolar cells occupying anterior 40 % – 50 % of calotte length when viewed laterally (Fig. 4 c, d). Cytoplasm of propolar and metapolar cells more darkly stained by hematoxylin than cytoplasm of other peripheral cells (Fig. 4 b, c). Verruciform cells present. Axial cell cylindrical in juveniles, swollen anteriorly in large individuals, extending forward to propolar cells (Figs 3 e, f, 4 b). About 25 vermiform embryos present per axial cell of large individuals. Vermiform embryos (n = 20) (Figs 3 c, 4 e, f). Full-grown vermiform embryos length 105 – 180 µm, width 22 – 35 µm. Peripheral cell number 24 (Table 2); trunk cells arranged in opposed pairs. Anterior end of calotte rounded or bluntly pointed. Axial cell bluntly pointed anteriorly, extending to the end of propolar cells; nucleus usually located in anterior half of axial cell. Anterior abortive axial cell absent. Axial cell of full-grown embryos with up to 8 agametes. Rhombogens (n = 20) (Figs 3 d, g, 4 b, g). Body similar in length to nematogens, length 950 – 2050 µm, width 150 – 310 µm. Peripheral cell number typically 24 (Table 2). Calotte cap-shaped, rounded anteriorly. Verruciform cells present. Axial cell shape and anterior extent similar to nematogens. One, rarely 2 or 3 infusorigens per axial cell of each parent individual. About 40 infusoriform embryos present per axial cell of large individuals. Accessory nuclei occasionally present in trunk cells. Infusorigens (n = 20) (Figs 3 h, 4 h). Mature infusorigens medium-sized; composed of 6 – 35 (mode 26) external cells (oogonia and primary oocytes) + 4 – 24 (mode 6) internal cells (spermatogonia, primary spermatocytes, and secondary spermatocytes) + 4 – 28 (mode 4) spermatozoa. Mean diameter of fertilized eggs, 12.6 µm; that of spermatozoa, 2.4 µm. Axial cell round, diameter 13 – 32 µm. Infusoriform embryos (n = 40) (Figs 3 i, j, 4 i – k). Full-grown embryos large, length 28.9 ± 1.7 µm (mean ± SD, excluding cilia); length-width-height ratio 1.0: 0.92: 0.88; shape ovoid, bluntly rounded; cilia at posterior end 6 µm long. Refringent bodies present, liquid, occupying anterior 30 % of embryo length when viewed laterally (Fig. 4 k). Cilia projecting from ventral internal cells into urn cavity (Fig. 4 k). Capsule cells containing small granules. Mature embryos with 35 cells: 31 somatic + 4 germinal cells. Somatic cells of several types present: external cells that cover a large part of the anterior and lateral surfaces of the embryo (2 enveloping cells); external cells with cilia on external surfaces (2 pairs of dorsal cells + 1 median dorsal cell + 2 dorsal caudal cells + 2 lateral caudal cells + 1 ventral caudal cell + 2 lateral cells + 2 posteroventral lateral cells); external cells with refringent bodies (2 apical cells); external cells without cilia (1 couvercle cell + 2 apical micro cells + 2 shield cells); internal cells with cilia (2 ventral internal cells); and internal cells without cilia (2 dorsal internal cells + 2 capsule cells + 4 urn cells). Each urn cell contains a single germinal cell and 2 nuclei (Fig. 4 k). All somatic nuclei appear pycnotic in mature infusoriform embryos.	en	Furuya, Hidetaka (2025): Two New Species of Dicyemids (Phylum Dicyemida) from Octopus conispadiceus (Mollusca: Cephalopoda: Octopoda) in Japanese Waters. Species Diversity 30 (2): 135-145, DOI: 10.12782/specdiv.30.135, URL: https://doi.org/10.12782/specdiv.30.135
F04E9478FFD4FFDE7B96FF2CFF1D2B04.taxon	discussion	Remarks. Dicyemodeca shirarikaense sp. nov. has a similar peripheral cell number to the other congeners: Dca. dogieli Bogolepova, 1957, Dca. deca (McConnaughy, 1957), Dca. delamarei (Nouvel, 1961), Dca. anthinocephalum Furuya, 1999, and Dca. kukii Furuya, 2018. However, Dca. shirarikaense sp. nov. differs from Dca. delamarei in calotte shape. The new species has conical or cap-shaped calotte, while Dca. delamarei has a typical calotte shape (Nouvel 1961). In infusoriform embryos, Dca. shirarikaense sp. nov. shares two unique cell types, namely the anterior micro cells and shield cells with Dca. anthinocephalum and Dca. kukii (Furuya 1999, 2018). However, the new species is distinguished from Dca. anthinocephalum by the number of cells of infusoriform embryos (35 vs. 42). Dicyemodeca shirarikaense sp. nov. is distinguished from Dca. dogieli and Dca. deca by lacking solid refringent bodies within the apical cell of infusoriform embryos (Bogolepova 1957; McConnaughy 1957).	en	Furuya, Hidetaka (2025): Two New Species of Dicyemids (Phylum Dicyemida) from Octopus conispadiceus (Mollusca: Cephalopoda: Octopoda) in Japanese Waters. Species Diversity 30 (2): 135-145, DOI: 10.12782/specdiv.30.135, URL: https://doi.org/10.12782/specdiv.30.135
F04E9478FFD4FFDE7B96FF2CFF1D2B04.taxon	etymology	Etymology. The specific name “ shirarikaense ” is derived from the Ainu language “ shirarika ”, meaning “ near the rocky shore, ” which is the origin of the type locality Shiranuka. Taxonomic summary. Type material. A syntype slide (NSMT-Me- 73) collected on 26 February 2019; additional syntypes on slide series No. OC 3956 (5 slides) in the author’s collection. Type locality. Off Shiranuka (42 ° 54 ′ N, 144 ° 12 ′ E), Hokkaido, Japan, depth 100 m. Other material examined. Slide series Nos OC 4149, 4150 (each 5 slide) collected off Shiranuka, depth 100 m, 11 May 2020 in the author’s collection. Host. Symbiotype, Octopus conispadiceus (Sasaki, 1917) (Mollusca: Cephalopoda: Octopoda), male (mature), 155 mm ML (NSMT-Mo- 85946). Site. Anterior ends (calottes) of cap-shaped individuals attaching the surface of renal appendages within the renal sac. Prevalence. In 43 of 47 specimens of hosts examined (91.5 %).	en	Furuya, Hidetaka (2025): Two New Species of Dicyemids (Phylum Dicyemida) from Octopus conispadiceus (Mollusca: Cephalopoda: Octopoda) in Japanese Waters. Species Diversity 30 (2): 135-145, DOI: 10.12782/specdiv.30.135, URL: https://doi.org/10.12782/specdiv.30.135
