Table 2 Characteristic features of the analysed Malacobdella species
From: DNA barcoding supports identification of Malacobdella species (Nemertea: Hoplonemertea)
Features | M. arrokeana (Ivanov et al. 2002 ) | M. japonica (Takakura 1897 ) | M. grossa (Müller 1776) |
|---|---|---|---|
Excretory pores | Dorso-lateral (40% of length) | Dorso-lateral (25% of length) (Yamaoka 1940) | Ventro-lateral |
Proboscis length | Most of the rhynchocoel, 80 to 90 | Two thirds of the rhynchocoel length (Yamaoka 1940) | Two thirds of the rhynchocoel length |
Proboscis retractor muscle | Curved dorsally and attached to the body muscular wall | Originates ventrally and ends freely in the parenchyma (Yamaoka 1940) | Originates ventrally next to the terminal sucker (Riepen 1933) |
Ovary colour (mature) | White or purple (Teso et al. 2006) | Rosy (Yamaoka 1940) | Olive green or yellowish green (Gibson 1968) |
Testicle colour (mature) | Pale rose (Teso et al. 2006) | White (Yamaoka 1940) | Rosy or pinkish hue (Gibson 1968) |
Nerve commissure | Dorsal in the posterior part of the intestine just before the anus | Far behind the anus along the posterior margin of the sucker (Yamaoka 1940) (posterior around the terminal sucker) | Dorsal in the posterior part of intestine, above the anus |
Host specificity | High (only in Panopea abbreviata) | High (only in Spisula sachalinensis) | Low (27 species) |
Geographic distribution | South Atlantic Ocean (from Uruguay to north Patagonian gulfs) | North Pacific Ocean (northern Japan) | North Atlantic Ocean (Europe and North America) North Pacific Ocean (North America) |