Marionina georgiana, (MICHAELSEN, 1888)

Klinth, Mårten J., Rota, Emilia, Martinsson, Svante, Prantoni, Alessandro L. & Erséus, Christer, 2022, New insights into the systematics of Lumbricillus and Marionina (Clitellata: Enchytraeidae) inferred from Southern Hemisphere samples, including three new species, Zoological Journal of the Linnean Society 194 (4), pp. 1103-1133 : 1126

MARIONINA GEORGIANA ( MICHAELSEN, 1888)

( FIG. 9D )

Pachydrilus georgianus Michaelsen, 1888: 65–66 , pl. II, fig. 7a, b.

Marionia georgiana – Michaelsen, 1889b: 29.

Marionina georgiana – Michaelsen in Pfeffer, 1890: 511; Beddard, 1895: 332; Michaelsen, 1900: 76; Nielsen & Christensen, 1959: 109; Brinkhurst & Jamieson, 1971: 662; Rota et al., 2008: 425–433, figs 2–6; Schmelz & Collado, 2008: 12–18, figs 1–13.

Pachydrilus (Marionina) georgiana – Černosvitov, 1937: 293.

Christensenia georgiana – Dózsa-Farkas & Convey, 1997: 483–484, fig. 9; partim.

Christensenidrilus georgiana [sic] – Dózsa-Farkas & Convey, 1998: 292; partim.

Non Marionina georgiana – Michaelsen, 1905a: 15–17, pl. I, fig. 2; Michaelsen, 1905b: 5; Stephenson, 1932: 241.

Type material studied: Lectotype CeNak V428 and paralectotypes CeNak V428 2, 5–17, in alcohol. Loc. South Georgia Island.

Type locality: South Georgia Island, near the German station 1882–1883, 54.533 S, 36.017 W, at low water mark, from slate debris, algal weeds and sponge canals, Febuary 1883 .

Additions to Michaelsen’s original description and recent redescriptions of types: Paired clusters of perikarya on prostomial nerves and at ventral ends of circumoesophageal connectives. Ventral nerve cord with small subbuccal bulb ( Fig. 9D ); see Marionina discussion above. Developing male cells enveloped in testis sac, distally frayed, releasing free-floating cysts, parts of which extend into X and XII in seminal vesicle.

Remarks: This species was thoroughly redescribed by Rota et al. (2008) and Schmelz & Collado (2008), but neither described the subbuccal bulb (which we could not make out in most specimens) and neither considered the male cells enveloped in a testis sac but both mention the large seminal vesicle.

Figures

Figure 9. A, Marionina sp. ‘Snow Is.’ (CE34647), anterior body (lateral view). B, Marionina aestuum, sectioned specimen BMNH 1933.2.23.895, cephalic region (lateral view). C, M. aestuum (CE12477), cephalic region (ventral view). D, Marionina georgiana (paralectotype 13), cephalic region (ventral view). Abbreviations are defined under ‘Taxonomy’. Scale bars: 100 μm.