Ceratopera pilifera, KARLING, 1986

CERATOPERA PILIFERA KARLING, 1986 View in CoL

( FIG. 4B, E, F)

Ceratopera pilifera Karling, 1986: 212–214 View in CoL , figs 58, 65–67.

New localities: Clover Point , Victoria, British Columbia, Canada (48°24 ′ 12 ″ N, 123°21 ′ 03 ″ W), algae in rocky lower intertidal (14/11/2016) GoogleMaps . Little Wolf Beach , Calvert Island, British Columbia, Canada (51°39 ′ 53 ″ N, 128°07 ′ 44 ″ W), algae in rocky lower intertidal (07/04/2016) GoogleMaps . Friday Harbor , San Juan Island, Washington, USA (48°32 ′ 42 ″ N, 123°00 ′ 44 ″ W), algae on the dock of the marine station (08/10/2016) GoogleMaps .

Known distribution: Northeast Pacific Ocean: Oregon ( Karling, 1986).

Material: Observations on five live animals. Three whole mounts ( BBM MI4046 – MI4048 ). 18S rRNA (G e n B a n k a c c e s s i o n # M F 3 2 1 7 4 9), 2 8S r R N A (GenBank accession # MF321759 View Materials ) .

Remarks: Animals are 0.7– 1 mm long and appear plumper and more Proxenetes- shaped than described by Karling (1986) ( Fig. 4B). Internal organization typical for species of Ceratopera with paired lenticular eyes, rostral rhabdite tracks, a pharynx located mid-body, paired testes situated behind the pharynx, paired ovaries and vitellaria. Two large ovate seminal vesicles are connected to the rounded copulatory bulb.

The stylet is 97–106 μ m long (x = 100 μ m, n = 3; non-axial: 52–57 μ m) and resembles the stylet of C. pilifera as described by Karling (1986). It consists of a curved stylet proper, measuring 74–80 μ m (x = 76 μ m, n = 3), with a 23- to 26- μ m-long (x = 24 μ m, n = 3) proximal base, and a curved, funnel-shaped, 46- to 47- μ m-long (x = 46 μ m, n = 3) accessory mantle piece ( Fig. 4F). These measurements correspond to the ones from the Oregonian specimens. The hair-like eponymous protrusion of the accessory mantle piece could not be observed in our specimens. However, a thickened part of the convex edge of the mantle piece (arrow in Fig. 4F) corresponds to this structure. Moreover, the needle-like structure on the accessory piece in figure 67 in Karling (1986) could easily be interpreted as a thickened edge rather than a hair-like protrusion.

The funnel-shaped and distally curled bursal appendage measures 78–88 μ m (x = 82 μ m; n = 3) and is typical for species of Ceratopera sensu Den Hartog. Distally it splits into two 29- to 32- μ m-long tubes (x = 31 μ m; n = 3).

Based on the strong resemblance of the stylet and bursal appendage with those of C. pilifera , we attribute our specimens to this species.