Plagiopyla mystax Nitla & Serra & Fokin & Modeo & Verni & Sandeep & Kalavati & Petroni, 2019

PLAGIOPYLA MYSTAX ( LYNCH, 1930) COMB. NOV.

1930: Lechriopyla mystax – Lynch, Univ. Calif. Publ. Zool., 33: 307–341; figs A, B1–3; p1s 34–36; figs 1–16 (original description, illustrated, no type material available).

1931: Lechriopyla mystax Lynch, 1930 – Kahl, Tierwelt Dtl., 21: 267; fig. 45.22 (guide; revision).

1946: Lechriopyla mystax Lynch, 1930 – Kudo, Protozoology, 3rd edn, CC Thomas ed., Springfield, p. 597; fig. 282c (revision).

1984: Lechriopyla mystax Lynch, 1930 – Berger & Lynn, J. Protozool., 31: 436, 441–442; figs 1B, 1–4, 8–28 (ultrastructural study).

2007: Lechriopyla mystax Lynch, 1930 – Jankowski, Russian Acad. Sci. , p. 793 (revision).

Improved diagnosis ( Fig. 18E): Body length 113– 174 µm, body width 86–133 µm after staining. Tubular part of the oral cavity curving anteriorly, then posteriorly. A fork-like structure, called the furcula (25–30 µm long) apparently supports part of the oral cavity. Number of somatic kineties estimated around 128. Striated band present (estimated length: 76 µm; width: 2.5–4.5 µm). One spherical to ovoid macronucleus (33 × 28 µm after staining) and a single micronucleus (11 × 7.5 µm in live specimens; 9 × 6.75 µm after staining; presumably of the endosomal-type). One contractile vacuole plus two accessory vacuoles. Cytoproct long 18–28 µm, located on the dorsal part of the cell. Spindle-shaped extrusomes (size: 8.5–10 × 0.5 µm).

Ty p e l o c a l i t y: I n t e s t i n e o f t h e s e a u r c h i n s Strongylocentrotus franciscanus and S. purpuratus , from Pacific Grove, California – USA ( Lynch, 1930).

Ecology and distribution: Endocommensal of Strongylocentrotus franciscanus , S. purpuratus ( Lynch, 1930) and S. pallidus ( Lynn & Strüder-Kypke, 2002) . Found in USA, California, Pacific Grove ( Lynch, 1930) and Venice ( Berger & Lynn, 1984), Washington in San Juan Island ( Lynn & Strüder-Kypke, 2002).

Gene sequences: 18S rRNA accession number: AF527757 View Materials ( Lynn & Strüder-Kypke, 2002; authors provide a picture of the living organism and the sample location: Washington in San Juan Island, in S. pallidus ) submitted as Lechriopyla mystax .

Remarks: Plagiopyla mystax was initially considered as belonging to a different genus ( Lechriopyla ) based on the orientation of the tubular part of the oral cavity and the presence of the furcula. For detailed discussion see above.