Doryporella spathulifera

Doryporella spathulifera (Smitt, 1868)

(Fig. 1; Table 1)

Lepralia spathulifera Smitt, 1868: 20, 124, pl. 26, figs 94–98.

Doryporella spatulifera: Norman 1903: 106.

Doryporella spathulifera: Grischenko, Mawatari & Taylor 2000: 248, fig. 1.

Material examined. Lectotype (designated here) SMNH-Type-1729a (Fig. 1), and paralectotype SMNH-Type-1729b; two colonies encrusting the same bivalve shell; Hinlopen Strait, Waigatsöarna, Svalbard, Norway; 79˚10’N 19˚E; depth 55 m. Leg. Swedish Arctic Expedition 1861.

Remarks. The four species of the genus Doryporella have been thoroughly described and illustrated in Grischenko et al. (2000, 2004). No type material of D. spathulata, the type species of the genus, was illustrated by these authors, although among the specimens examined (Grischenko et al. 2000, p. 248) some are from the Swedish Arctic Expedition and collected off Svalbard, as the type material illustrated here.

The two syntype colonies are both fan-shaped, 3.8 x 5.5 mm (lectotype) and 3.5 x 4.2 mm (paralectotype) in size respectively, with subsequent generations of autozooids budded only distally from the ancestrula (Fig. 1A).

The study of this material allows a better observation of the ancestrula confirming it to be tatiform (Fig. 1B), about 290 µm long by 220 µm wide; nine spines, about 70 µm long, are placed on the smooth gymnocyst and encircle the subcircular opesia, 175 µm long by 165 µm wide; the gymnocyst is well-developed proximally (90–100 µm); the opesia is outlined by a raised rim indented by the spines. An additional observation is related to the ovicell, which in the same colony can either be kenozooidal, occupying the space between autozooids and developed at the colony growing edge (Fig. 1D), or produced by the distal zooid and occupying most of its frontal surface. In this latter case, the distal zooid sometimes fails to bud the frontal, centrally placed, adventitious avicularium (Fig. 1C).

Compared to size measurements reported in Grischenko et al. (2000), the syntype colony shows slightly larger autozooids and ovicells, but narrower opesia (Table 1); frontal and latero-oral avicularia are similar in size.