Limnodriloides parahastatus Erséus, 1985

Wang, Hongzhu & Erséus, Christer, 2004, New species of Doliodrilus and other Limnodriloidinae (Oligochaeta, Tubificidae) from Hainan and other parts of the north-west Pacific Ocean, Journal of Natural History 38 (3), pp. 269-299 : 294-295

Limnodriloides parahastatus Erséus, 1985

(figure 13)

Limnodriloides parahastatus Erséus, 1985: 147–149 , figure 13; Erséus, 1990a: 297–298, figure 16.

New material. IHB HANA 2000017f, one specimen from Station SY00-9C.

Brief description of new material. Specimen incomplete, 5.1 mm long with 39 (anterior) segments. Prostomium blunt. Clitellum not developed. Somatic chaetae (figure 13A) 45–50 m m long, 2.0– 2.5 m m thick, with upper teeth shorter and thinner than lower; two to three per bundle anteriorly, (one) two per bundle in post-clitellar segments. All chaetae absent in XI. Spermathecal chaetae 55 m m long, about 3.0 m m thick, with ectal third grooved. Chloragogen cells from VI onwards. Vasa deferentia coiled, shorter than atria. Atria tubular; ampullae 130 m m long, 17–22 m m wide; atrial ducts 75 m m long, 10 m m wide, opening to exterior through complex bodies of tissue. Prostatic pads oval, about 24 m m long. Nuclei of prostatic glands oblong, maximally 7 m m long, 5 m m wide. Spermathecae (figure 13B) small; ducts 30 m m long, 24 m m wide; ampullae oval, 50 m m long, 30 m m wide, with a few sperm bundles in lumina.

Remarks. This post-copulatory specimen fits well the description of a single precopulatory worm reported from Hong Kong (Erséus, 1990a), but in the Hainan worm, the upper teeth of the somatic chaetae are shorter than the corresponding lower teeth, while in the Hong Kong material, the upper and lower teeth were of about same length (Erséus, 1990a: figure 16A). Erséus (1990a) listed five differences between the Hong Kong specimen and the type specimen from Saudi Arabia. He pointed out that the Chinese form may be separate, but more specimens are needed from both localities to enable a comprehensive comparison. Erséus (1990a) also stated that the atrial ducts of his Hong Kong material were poorly granulated, whereas those of the holotype were heavily granulated (see also Erséus, 1985). However, a re-examination of the holotype shows that the granules of the atrial ducts almost cannot be observed; the heavy granulation was simply inferred from the irregularity of the inner epithelium. Thus, it now seems even more likely that the form from southern China indeed is conspecific with the original material of L. parahastatus .

Distribution and habitat. Southern China (new record for Hainan) and Saudi Arabia. Shallow subtidal and lower intertidal, sandy mud.