Lumbricillus sp. F

Klinth, Marten J., Rota, Emilia & Erseus, Christer, 2017, Taxonomy of North European Lumbricillus (Clitellata, Enchytraeidae), ZooKeys 703, pp. 15-96 : 28-30

Lumbricillus sp. F Fig. 10

Lumbricillus sp. F; Klinth et al. 2017.

Material examined.

SMNH 152832 (CE2659), one mature specimen from the United Kingdom. For information on specimen collection locality and GenBank accession number see Appendix 1.

Description.

Colour of worms unknown. Length (fixed worm) more than 3.1 mm (amputated specimen), first 15 segments 2.2 mm long, width at clitellum 0.35 mm. More than 21 segments. Chaetae slightly sigmoid (Fig. 10A). Dorsal bundles with 3-5 chaetae anterior to clitellum, 3-4 chaetae in postclitellar segments. Ventral bundles with 3-5 chaetae anterior to clitellum, 2-4 chaetae posteriorly. The worm’s longest measured chaetae 45 µm long, about 3 µm wide. Clitellum extending over XII– 1/2XIII. Head pore at 0/1. Epidermis with transverse rows of gland cells.

Coelomocytes numerous, 15 µm long, round, oval or spindle-shaped, granulated with distinct nucleus. Paired pharyngeal glands present in IV, V and VI (Fig. 10B). Dorsal vessel originating in XIV. Nephridia possibly observed in X, about 95 µm, shape uncertain. Brain elongate, with posterior incision.

Male genitalia paired (Fig. 10D). Testes originating in XI, extending forwards into X, with testis sacs forming regular club-shaped lobes. Sperm funnels in XI, 175 µm long, 90 µm wide, making them about twice as long as wide. Vasa deferentia not observed. Penial bulbs round, 85 µm in diameter. Ovaries in XII. About two or three mature eggs present.

Spermathecae (Fig. 10C) 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. Sperm concentrated in inner part of ampulla, embedded in wall of ampulla. Spermathecae 210 µm long, 80 µm wide at widest part of ampulla. Gland cells surrounding ectal pore, forming compact mass, 110 µm in diameter at its widest part. Possibly one subneural gland in XIV, 50 µm long.

Geographical distribution. Only known from the United Kingdom and Norway (unpublished results).

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 is not recommended. Lumbricillus sp. F is genetically placed within the lineatus group; it is possibly phylogenetically close to L. kaloensis , but this is not strongly supported (Fig. 1).