Prostoma macradenum, Sun & Yin, 1995

Kajihara, Hiroshi, 2025, A taxonomic revision of the freshwater monostiliferous hoplonemertean genus Prostoma Dugès, 1828 (Nemertea: Eumonostilifera): a radical solution or an over-lumping?, Zootaxa 5646 (4), pp. 451-500 : 469

16. macradenum Sun & Yin, 1995

Source. In the trinomen Prostoma eilhardi macradenum by Sun & Yin (1995: 135, figs 1–3).

Type locality. A pond called Xiaoxihu (meaning “small west lake”) in Zhongshan Park, Qingdao, China ( Fig. 9 ) .

Etymology. Adjective, macradenus, - a, - um; from Ancient Greek µᾰκρός (makros, “large”), ᾰ̓δήν (adḗn, “gland”), and the Latin adjective forming suffix - us, referring to the large cephalic gland.

Remarks. Sun & Yin (1995) noted that Prostoma eilhardi macradenum was similar to Prostoma graecense and Prostoma jenningsi , but could be distinguished by its indistinct and unciliated oesophagus, the rhynchodaeum without longitudinal musculature, and the proboscis with 9–10 nerves. Compared to the nominotypical P. e. eilhardi , the new subspecies was thought to be differentiated by its voluminous cephalic glands extending posteriorly behind the dorsal cerebral commissure. Elevated to the species rank by Chernyshev et al. (1998: 61), but it was listed as a subspecies in Sundberg & Gibson (2008) and Strand & Sundberg (2015). It is herein considered synonymous with P. clepsinoides until future studies prove otherwise.

Figures

FIGURE 9. World map showing distribution of 25 nominal species of freshwater monostiliferous hoplonemerteans indicated by boxes and respective species-group names (three subterranean species are indicated with ‘S’ in parentheses); circles, diamond, and triangles indicate localities of DNA-barcoded individuals; circles, Haplogroup 1 from the UK, Sweden (SE), Italy (IT), Macedonia (MK), Japan (JP), New Zealand (NZ), Mexico (MX), Indiana (IN), and Massachusetts (MA); diamond, Haplogroup 2 from Norway (NO); triangles, Haplogroup 3 from Sweden (SE) and California (CA).