Paralumbricillus sp.

Paralumbricillus sp. “ Denmark ” Figure 15 View Figure 15

Material examined. SMNH 212154 View Materials ( CE34810 ) , SMNH 212155 View Materials ( CE34811 ) & SMNH 212156 View Materials ( CE34812 ) three immature or partially mature specimens from Grisetå Udde Peninsula, Oddesund, Struer, Jutland , Denmark. In upper intertidal. Coll. M. Klinth & E. Eriksson, 16 May 2018. For details on collection site and GenBank accession numbers see Table S1 .

Description. Length of first 25–37 segments 2.4–3.2 mm (fixed, amputated specimens); first 15 segments 1.2–1.4 mm long; width at clitellum 0.18–0.19 mm. Chaetae straight with ental hook. Dorsolateral and ventral bundles with 2 chaetae anterior and posterior to clitellum. Each worm’s longest measured chaetae 40–50 µm long, about 5 µm wide. Clitellum not developed. Head pore at 0/1.

Coelomocytes numerous, about 10–20 µm long, round or oval, granulated with distinct nucleus. Paired pharyngeal glands present in IV, V and VI; each pair converging dorsally ( Figure 15A View Figure 15 ); third pair sometimes extending into VII. Dorsal vessel originating in XII–XIII. Nephridia observed in 7/8–9/10, and postclitellar segments, about 70–75 µm long. Anteseptale small, consisting of funnel only. Postseptale oval, tapering into posteroventral efferent duct ( Figure 15B View Figure 15 ). Brain with posterior incision.

Male genitalia only partially developed. Testes in XI, ovaries and penial bulbs in XII. Spermathecae developing in V, with pores at lateral line. No midventral subneural glands observed.

Geographical distribution including BOLD data. Only known from one locality in Jutland, Denmark.

Remarks. Unfortunately, we found no fully mature specimens of this species. It is genetically supported as sister to the remaining Paralumbricillus in our taxon sample, but with rather large genetic distance ( Figure 2 View Figure 2 ). Having only 2 chaetae per bundle supports its inclusion into Paralumbricillus and suggests that it could be, e.g., P. cervisiae , P. christenseni or P. westheidei , but mature specimens are required to resolve this.