Marionina argentea Michaelsen, 1889

Torii, Takaaki, Akagi, Tomohiro, Uchino, Toru & Kobayashi, Tohru, 2018, New descriptions of enchytraeid species (Clitellata: Enchytraeidae) from Korea, Journal of Species Research 7 (1), pp. 80-91 : 90

7. Marionina argentea Michaelsen, 1889 sensu lato

( Fig. 9 )

Marionina argentea Michaelsen, 1889: 15-17 : fig. 6a, b; Dózsa-Farkas and Hong, 2010: Table 1, for complete synonymy Rota: 2013.

New Korean name: Dol-ae-jireongi (ǕOiNjffiḍ)

Material examined. Korea, Jeollabuk-do, Namwongun, Unbong-myeon, Mt. Jiri , Bamsagol Valley , Litter layers in deciduous forest (35°20′56.4″N, 127°33′03.9″E, 569 m asl.), 18 September 2008 and 6 October 2008, Y. Hong coll.

Diagnosis. 3-7 mm long and about 180 μm wide worms in vivo, with 19-26 segments. Color intensely white due to aggregations of colomocytes. Chaetae thin, straight, sharply pointed ectally, distinctly hooked entally. Two chaetae in bundles throughout, absent laterally in II. Pharyngeal glands broadly united dorsally in IV and V, separate and elongate in VI ( Fig. 9A ) Dorsal vessel from XIII, blood colorless. Preclitellar nephridia in one or two positions of 7/8, 8/9, or 9/10. Coelomocytes filled with coarse refractile granula, dark-black in transmittent light ( Fig. 9D ). Clitellum saddle-shaped, gland cells in separate rows. Seminal vesicle absent or small. Sperm funnel ( Fig. 9C ) small, ca 1.5 times as long as width, male glandular bulb small. No subneural gland. Spermathecal ectal duct with slight glandular swellings and one or two slightly larger glands at orifice, ampullae oval or pear-shaped, lumens contain spermathozoa. Ental ducts short, and communicate separately with oesophagus ( Fig. 9E ). Mostly one large mature egg present at a time ( Nielsen and Christensen, 1959, Schmelz and Collado, 2010).

Remarks. The genus Marionina Michaelsen, 1890 is a polyphyletic enchytraeid genus represented by about 100 nominal species ( Rota et al., 2008). This genus was originally described in 1889. It was initially named Marionia , but was corrected to Marionina one year later by Michaelsen himself. According to ICZN (1999), a new replacement name has its own author and date. Thus, the correct nomenclature of the genus should be Marionina Michaelsen, 1890 ( Rota et al., 2008). Marionina argentea species is a complex. Rota (2013) has carried out a revision of this complex, described 3 new species, and separated M. argentea sensu stricto from this group. We were unable to take this complicated segregation in these Korean specimens into consideration. Therefore, we named our specimens ‘ M. argentea sensu lato ’.

Habitat and distribution. In wet sites, also aquatic. In soils, often in deeper strata with groundwater contact. Slightly salt-tolerant. Not at acidic sites. Very common and cosmopolitan ( Schmelz and Collado, 2010).

Deposition. NIBRIV0000544615.

Figures

Fig. 9. Marionina argentea. A. Pharyngeal glands (schematic); B. Brain; C. Sperm funnel; D. Coelomocytes; E. Spermathecae. Scale bars: 50μm.