Pseudicyema anemophilum, Furuya & Moritaki, 2022

Furuya, Hidetaka & Moritaki, Takeya, 2022, Fourteen New Species of Dicyemids (Phylum: Dicyemida) from Seven Species of Decapodiformes (Mollusca: Cephalopoda) in the Kumano Sea, Japan, Species Diversity 27 (1), pp. 181-226 : 207-213

publication ID	https://doi.org/ 10.12782/specdiv.27.181
publication LSID	lsid:zoobank.org:pub:03A070DC-A02C-4FF8-A00D-FD59C7614189
persistent identifier	https://treatment.plazi.org/id/857E1DDA-04E8-4311-9638-8DB26B2E7B49
taxon LSID	lsid:zoobank.org:act:857E1DDA-04E8-4311-9638-8DB26B2E7B49
treatment provided by	Felipe
scientific name	Pseudicyema anemophilum
status	sp. nov.

Treatment

Pseudicyema anemophilum sp. nov. [New Japanese name: Kazeno-nihaichū] ( Figs 20 View Fig , 21 View Fig ; Tables 1–3)

Diagnosis. Small-sized dicyemid, body length reaching 1250 µm. Calotte cap-shaped. Vermiform stages with 29–34 peripheral cells: 4 propolar cells+4 metapolar cells+ 2 parapolar cells+19–24 trunk cells. Infusoriform embryos with 39 cells; refringent bodies solid; and 2 nuclei present in each urn cell.

Description. Nematogens ( Figs 20a, b View Fig , 21a, c View Fig ). Body length 650–1250 µm, width 65–75 µm; widest in region of parapolars; trunk width mostly uniform. Peripheral cell number 29–34 ( Table 2): 4 propolar cells+4 metapolar cells+2 parapolar cells+17–22 diapolar cells+2 uropolar cells. Calotte cap-shaped, rounded anteriorly; cilia about 4 µm long, oriented anteriorly. Propolar cells equal to or larger than metapolar cells, their nuclei equal to or smaller than metapolar cell nuclei. Propolar cells occupy anterior 50% of calotte length when viewed laterally ( Figs 20a, b View Fig , 21c View Fig ). Cytoplasm of propolar cells more darkly stained by hematoxylin than that of other peripheral cells ( Fig. 20a, b View Fig ). Axial cell cylindrical, rounded anteriorly, extending forward to base of propolar cells ( Fig. 20a, b View Fig ). About 6 vermiform embryos present per axial cell of large individuals. Accessory nuclei seen in trunk peripheral cells.

Vermiform embryos ( Figs 20c View Fig , 21d, e View Fig ). Full-grown vermiform embryos length 52–77 µm, 17–19 µm in width. Peripheral cell number 29–34 ( Table 2); trunk cells arranged in opposed pairs. Anterior end of calotte rounded. Axial cell pointed anteriorly, extending to the base of propolar cells ( Figs 20c View Fig , 21d, e View Fig ). Axial cell of full-grown embryos with 2 agametes.

Rhombogens ( Figs 20d View Fig , 21f, g View Fig ). Body length similar 480–1100 µm, similar to that of nematogens, in length and 40–52 µm in width. Peripheral cell number typically 29–34 ( Table 2). Calotte, axial cell shape and anterior extent similar to nematogens. Maximum of 2 infusorigens present in the axial cell of each parent individual. About 15 infusoriform embryos present per axial cell of large individuals.

Infusorigens ( Figs 20g View Fig , 21h; n View Fig =20). Mature infusorigens medium-sized; composed of 5–12 (mode 5) external cells (oogonia and primary oocytes)+2–4 (mode 4) internal cells (spermatogonia, primary spermatocytes, and secondary spermatocytes)+3–9 (mode 6) spermatozoa. Mean diameter of fertilized eggs 11.7 µm; that of spermatozoa 2.5 µm. Axial cell round or ovoid, diameter 11–18 µm.

Infusoriform embryos ( Figs 20e, f View Fig , 21i–k; n View Fig =20). Fullgrown embryos large, length 22.6±1.4 µm (mean±SD, excluding cilia); length–width–height ratio 1.0: 0.84: 0.78; shape ovoid, pointed posteriorly; cilia at posterior end 7 µm long. Refringent bodies present, solid, occupying anterior 30–40% of embryo length when viewed laterally ( Fig. 20f View Fig ). Cilia project from ventral internal cells into urn cavity ( Fig. 21k View Fig ). Capsule cells contain small granules ( Fig. 21k View Fig ). Mature embryos with 39 cells: 35 somatic+4 germinal cells. Somatic cells of several types present: external cells covering large part of anterior and lateral surfaces of 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 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 2 nuclei and a germinal cell ( Fig. 21k View Fig ). All somatic nuclei pycnotic in mature infusoriform embryos.

Remarks. Pseudicyema anemophilum sp. nov. is the first species of the genus found in Sepia kobiensis and only the fourth species to be described in the genus. It is distinguishable from other 2 species, P. truncatum ( Whitman, 1883) and P. nakaoi Furuya, 1999 , in the calotte shape (cap-shaped vs. disc-shaped) and the number of peripheral cells of vermiform stages (29–34 vs. 22) ( Nouvel 1947; Furuya 1999). Pseudicyema anemophilum sp. nov. is very similar to P. cappacephalum Furuya, 2009 in the calotte shape and the number of infusoriform embryos but the new species is clearly distinguished by the maximum number of infusorigens (2 vs. 3) and the range of peripheral cells of vermiform stages (29–34 vs. 32–34) ( Furuya 2009).

Etymology. The species name is an adjective composed of two Ancient Greek roots, anemos and - philos meaning “wind” and “like”, because host specimens were all collected under windy conditions.

Taxonomic summary. Type material: a syntype slide (NSMT-Me-60) collected on 14 April 2018; additional syntypes on slide series No. SK5792 (5 slides) in the author’s collection.

Type locality: off Owase (34°01′N, 136°35′E), Mie Prefecture, Honshu, the Kumano Sea, Japan, depth 150 m GoogleMaps .

Other materials examined: slide series No. SK3515, 3516 (each 5 slide) collected off Minami-Ise (34°08′N, 136°35′E), Mie Prefecture, Honshu , the Kumano Sea, Japan, depth 150 m, in the author’s collection GoogleMaps .

Host: symbiotype, Sepia kobiensis Hoyle, 1855 (Mollusca: Cephalopoda: Sepiida ), female (immature), 79 mm ML (NSMT-Mo-85903).

Collector of host: T. Moritaki.

Site : anterior ends (calottes) attach to surfaces of the renal appendages or inserted into crypts of the renal appendages within the renal sacs.

Prevalence: in 7 of 30 host specimens examined (23.3%).

Pseudicyema cupulacephalum sp. nov. [New Japanese name: Kupura-nihaichū] ( Figs 22 View Fig , 23 View Fig ; Tables 1–3)

Diagnosis. Small-sized dicyemid, body length reaching 1150 µm. Calotte cap-shaped. Vermiform stages with 29–35 peripheral cells: 4 propolar cells+4 metapolar cells+ 2 parapolar cells+19–25 trunk cells. Infusoriform embryos with 39 cells; refringent bodies solid; and 2 nuclei present in each urn cell.

Description. Nematogens ( Figs 22a–c View Fig , 23a, c View Fig ). Body length 450–980µm, width 40–60 µm; widest in region of parapolars; trunk width mostly uniform. Peripheral cell number 29–35 ( Table 2): 4 propolar cells+4 metapolar cells+2 parapolar cells+17–23 diapolar cells+2 uropolar cells. Calotte cap-shaped, rounded anteriorly; cilia about 4 µm long, oriented anteriorly. Propolar cells equal to or larger than metapolar cells, their nuclei equal to or smaller than metapolar cell nuclei. Propolar cells occupy anterior 40–50% of calotte length when viewed laterally ( Figs 22b View Fig , 23c View Fig ). Cytoplasm of propolar cells more darkly stained by hematoxylin than that of other peripheral cells ( Fig. 22a–c View Fig ). Axial cell cylindrical, rounded anteriorly, extending forward to the base of metapolar cells ( Fig. 22a, b View Fig ). About 6 vermiform embryos present per axial cell of large individuals. Accessory nuclei seen in trunk peripheral cells.

Vermiform embryos ( Figs 22d View Fig , 23d, e View Fig ). Full-grown vermiform embryos length 57–105 µm, 14–20 µm in width. Peripheral cell number 29–35 ( Table 2); trunk cells arranged in opposed pairs. Anterior end of calotte rounded. Axial cell pointed anteriorly, extending to the base of propolar cells ( Figs 22d View Fig , 23e View Fig ). Axial cell of full-grown embryos with 2 agametes.

Rhombogens ( Figs 22d View Fig , 23f, g View Fig ). Body length 680–1150 µm, similar to that of nematogens, in length and 35–60 µm in width. Peripheral cell number typically 29–35 ( Table 2). Calotte, axial cell shape and anterior extent similar to nematogens. Maximum of 3 infusorigens present in the axial cell of each parent individual. About 35 infusoriform embryos present per axial cell of large individuals.

Infusorigens ( Figs 22i View Fig , 23h; n View Fig =20). Mature infusorigens medium-sized; composed of 3–9 (mode 6) external cells (oogonia and primary oocytes)+2–4 (mode 3) internal cells (spermatogonia, primary spermatocytes, and secondary spermatocytes)+2–11 (mode 4) spermatozoa. Mean diameter of fertilized eggs 11.2 µm; that of spermatozoa 2.0 µm. Axial cell round or ovoid, diameter 11–16 µm.

Infusoriform embryos ( Figs 22e, f View Fig , 23i–k; n View Fig =20). Fullgrown embryos large, length 21.6±1.2 µm (mean±SD, excluding cilia); length–width–height ratio 1.0: 0.85: 0.83; shape ovoid, pointed posteriorly; cilia at posterior end 7 µm long. Refringent bodies present, solid, occupying anterior 30–40% of embryo length when viewed laterally ( Figs 22h View Fig , 23k View Fig ). Cilia project from ventral internal cells into urn cavity ( Fig. 23k View Fig ). Capsule cells contain small granules ( Fig. 23k View Fig ). Mature embryos with 39 cells: 35 somatic+4 germinal cells. Somatic cells of several types present: external cells covering large part of anterior and lateral surfaces of 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 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 2 nuclei and a germinal cell ( Fig. 23k View Fig ). All somatic nuclei pycnotic in mature infusoriform embryos.

Remarks. Pseudicyema cupulacephalum sp. nov. is the first species of the genus found in S. lorigera and is the fifth species to be described in this genus. It is distinguishable from two other species, P. truncatum and P. nakaoi , in the calotte shape (cap-shaped vs. disc-shaped) and the number of peripheral cells of vermiform stages (29–35 vs. 22) ( Whitman 1883; Nouvel 1947; Furuya 1999). Pseudicyema cupulacephalum sp. nov. is very similar to P. cappacephalum , and P. anemophilum sp. nov. in the calotte shape and the number of infusoriform embryos, but is distinguished by the maxum number of infusorigens (2 vs. 3) and the range of peripheral cells of vermiform stages (29–35 vs. 32–34 and 29–34) ( Furuya 2009).

Etymology. The species name “ cupulacephalum ” is an adjective composed of two Ancient Greek roots, kýpello and - kephalos, meaning “cup” and “-headed” in reference to the characteristic anterior part of vermiform embryos.

Taxonomic summary. Type material: a syntype slide (NSMT-Me-66) collected on 14 December 2018; additional syntypes on slide series No. SL3920 (5 slides) in the author’s collection.

Type locality: off Minami-Ise (34°04′N, 136°33′E), Mie Prefecture, Honshu, the Kumano Sea, Japan, depth 250 m GoogleMaps .

Other materials examined: slide series No. SL4118 (5 slides) collected off Minami-Ise (34°09′N, 136°36′E), Mie Prefecture, Honshu, the Kumano Sea, Japan, depth 180 m, 5 December 2019, in the author’s collection GoogleMaps .

Host: symbiotype, Sepia lorigero Wülker, 1910 (Mollusca: Cephalopoda: Sepiida ), female (mature), 211 mm ML (NSMT-Mo-85908).

Collector of host: T. Moritaki.

Site : anterior ends (calottes) attach to surfaces of the renal appendages or inserted into crypts of the renal appendages within the renal sacs.

Prevalence: in 3 of 10 host specimens examined (33.3%).