Lumbricillus sp. G

Klinth, Marten J., Rota, Emilia & Erseus, Christer, 2017, Taxonomy of North European Lumbricillus (Clitellata, Enchytraeidae), ZooKeys 703, pp. 15-96 : 27

Lumbricillus sp. G Fig. 8

Lumbricillus sp. G; Klinth et al. 2017.

Material examined.

Specimen SMNH 152834 (CE2246) & SMNH 152835 (CE2661), one mature and one immature specimen from the United Kingdom, and ZMBN 107942 (CE23373), one immature specimen from Norway. For information on specimen collection localities and GenBank accession numbers see Appendix 1.

Description.

Colour of worms unknown. Length (fixed worms) more than 3.3-4.1 mm (amputated specimens), first 15 segments 2-2.8 mm long, width at clitellum 0.42-0.49 mm. More than 17-33 segments. Chaetae slightly sigmoid (Fig. 8A). Dorsal bundles with 2 -5 chaetae anterior to clitellum, 3-6 chaetae in postclitellar segments. Ventral bundles with 3-6 chaetae anterior to clitellum, 3-4 chaetae posteriorly. Each worm’s longest measured chaetae 55-60 µm long, about 5 µm wide. Clitellum extending over XII– 1/2XIII. Head pore at 0/1. Epidermis with transverse rows of gland cells.

Coelomocytes numerous, 15-30 µm long, round, oval or spindle-shaped, granulated with distinct nucleus. Paired pharyngeal glands present in IV, V and VI (Fig. 8B). Dorsal vessel originating in XIII–XV. Nephridia not observed. Brain elongate, further details unknown.

Male genitalia paired (Fig. 8D). Testes originating in XI, extending forwards into IX, with testis sacs forming regular club-shaped lobes. Sperm funnels in XI, extending backwards into XII, 335-430 µm long, 180 µm wide, making them about 1.9-2.4 times longer than wide, funnels tapering towards vasa deferentia. Most of vasa irregularly coiled in XII, 15 µm wide. Penial bulbs pear-shaped, 110 µm in diameter. Ovaries in XII. One mature egg present in the single mature individual.

Spermathecae (Fig. 8C) in V, spindle-shaped, without distinct ampulla. Ectal duct short, widening into ampulla. Ampulla with constriction midway, dividing it into two sections, the inner of which connecting with oesophagus. No sperm observed. Spermathecae 210 µm long, 80 µm wide at widest part of ampulla. Gland cells surrounding ectal pore, forming compact mass, 105 µm in diameter at its widest part. Two midventral subneural glands in XIII–XIV, 70 µm and 90 µm long, respectively.

Geographical distribution.

Only known from Norway and the United Kingdom.

Remarks.

Unfortunately only one mature specimen was available for this study making it difficult to assign it to a known species. On the other hand, the description of a new species on such limited material would be premature. Lumbricillus sp. G is genetically placed within the lineatus group (Fig. 1).