Cribrilina (Juxtacribrilina) flavomaris, Yang & Seo & Min & Grischenko & Gordon, 2018

Yang, Ho Jin, Seo, Ji Eun, Min, Bum Sik, Grischenko, Andrei V. & Gordon, Dennis P., 2018, Cribrilinidae (Bryozoa: Cheilostomata) of Korea, Zootaxa 4377 (2), pp. 216-234 : 219-222

Cribrilina (Juxtacribrilina) flavomaris n. sp.

( Figs 1–4 , 8–10)

Etymology. Latin ‘ flavus ’, yellow, and ‘ mare ’, sea, alluding to the distribution of the species only in the Yellow Sea.

Material examined. Holotype: NIBRIV0000805949 , Cheongpodae, Yellow Sea coast , 36.6334° N, 126.2997° E, 26 May 2017, low intertidal zone. Paratype: NIBRIV 0 0 0 0 805955, same data as for holotype. Other material: Baengnyeong Island: Hwadong, 1 colony; Dumujin, 24 colonies, Yeonhwa-ri, 38 colonies. West coast of Korea: Cheongpodae, 70 colonies.

Material from other regions, not attributable to C. flavomaris n. sp.: SEM micrographs of NHMUK 1963.3.30.135, Hardanger Fjord, Norway; NHMUK 1899.7.1.1062, Shetland Is.; NHMUK 1911.10.1.668, Nantucket, Massachusetts; NHMUK 1991.9.27.145 Friday Harbor, Washington.

Description. Colony encrusting, unilaminar, multiserial, up to 7 mm in diameter or length, white. Autozooids more or less subhexagonal to elongate-oval with truncate or angled proximal margins, mostly widest mid-length. Frontal shield comprising 11–19 (mean 16) costae ( Figs 1, 4 ), pinnate except for suboral pair, midline fusions irregular, with no clear boundaries; 3–5 subrounded to oval lacunae between adjacent costae; each costa with single lumen pore (pseudopore) near tip. Gymnocyst scarcely visible laterally, slightly more so proximally. In central part of colony some infertile zooids budded adventitiously and semi-erect, with fewer (7–8) costae and three distal-oral spines. Orifice more or less transversely D-shaped, wider than long, proximal margin defined and overtopped by first pair of costae that project obliquely frontalwards, their tips touching or crossing; distal rim of orifice with four articulated oral spines, the middle pair smaller. No avicularia. Ovicellate zooids occasional in zooidal series or reparative and semi-adventitious (Figs 9, 10), generally smaller than autozooids, with 6–12 frontal-shield costae. Dwarf fertile zooids ( Figs 1 , 8) produced adventitiously from incised pores ( Fig. 3 ) on proximolateral corners of gymnocyst in a number of regular autozooids, overall similar to autozooids, but with fewer costae (six); vestigial ooecium comprising a very small median element, like a short, flattened spine, across which meet a pair of broadly flattened latero-oral costae (Fig. 8), each with tiny subterminal pseudopore. Embryo salmon-pink. Polypide with 12–13 tentacles. Basal pore chambers at least three in distal half of zooid, one mid-distal, two distolateral. Ancestrula ( Fig. 2 ) like autozooids, with 10–12 costae including suboral pair.

Measurements. ZL, 317–409 (360) µm; ZW, 178–244 (209) µm; OrL, 59–77 (67) µm; OrW, 85–103 (97) µm; OoL 139–211 (186) µm; OoW 143–169 (157) µm.

Remarks. Our specimens from the Yellow Sea coastal localities at Baengnyeong Island and Cheongpodae, Korea, are not conspecific with European Cribrilina (J.) annulata , although there are obviously similarities, especially in autozooidal characters, which are overlapping. Bishop (1994) recorded 7–16 costae and 2–5 intercostal lacunae in regular autozooids, but his illustrated specimens show the costae to be more discrete, with tips that slightly interdigitate. Specimens from Alaska and Hokkaido had overlapping numbers. The differences in ooecial construction, however, appear more significant. We have examined SEMs of material seen by Dick et al. (2005) from Alaska and by Grischenko et al. (2007) from eastern Hokkaido, and of a specimen identified by Grischenko (1997) from the Commander Islands, and have been able to compare these with SEMs of Cribrilina (J.) annulata from Norway; the comparisons show several differences, as seen in the tabulation in Table 2. We believe that at least two other undescribed species are recognizable in the North Pacific, one found at Akkeshi Bay and the Commander Islands, and one found in Alaska and Washington State. It is not our place to describe them here, nor can we nominate type material, but we do wish to highlight their existence.

In Figs 5–7 we illustrate ooecia in C. annulata from Norway and the Shetland Islands, and, in Figs 11–13, similar species from the northern Pacific, for comparison with that from Korea (Figs 8–10). The relative form and arrangement of the median vestigial ooecial flap and associated latero-oral costal spines obviously differs. Whereas the tiny ooecial flap in material from Cheongpodae, Korea, is short and narrow, it is 2–3 times broader in the Japanese, Russian and Alaskan material. We believe that eventual gene sequencing will confirm our interim conclusions concerning species diversity across the North Pacific from Korea to Washington State. Embryos were seen in late May (late spring) in specimens from Cheongpodae.

Distribution. Korea: Baengnyeong Island, on rock, shell and the coralline alga Clathromorphum ; Cheongpodae, on rock and shell. So far known only from the low intertidal zone.

Reginella Jullien, 1886

Figures

FIGURES 1–4. Cribrilina (Juxtacribrilina) flavomaris n. subgen. et sp., 1–3, Cheongpodae, 4, Baengnyeong Island. 1, autozooids near colony margin and developing dwarf females, an early stage arrowed; 2, ancestrula and daughter zooid; 3, proximal part of autozooid showing a pair of gymnocystal budding sites (frontal pore-chambers) of future dwarf zooids; 4, autozooids at growing margin showing elevation of tips of suboral spine pair.Scale bars:1, 500 µm; 2, 4, 200 µm; 3, 50 µm; 4, 400 µm.

FIGURES 5–7. Cribrilina (Juxtacribrilina) annulata (Fabricius): 5, NHMUK Hardanger Fjord, Norway; 6–7, NHMUK Shetland Is. 5, adventitious ovicellate zooid; 6, ooecium at colony margin with transverse costal spines broken off the front; 7, ooecium from same colony with transverse costal spines in place; notice short median suture in ooecium. FIGURES 8–10. Cribrilina (Juxtacribrilina) flavomaris n. subgen. et sp.: 8, Cheongpodae; 9–10, Baengnyeong Island. 8, dwarf ovicellate zooid showing only six frontal-shield costae, and the vestigial median ooecium flap and paired flattened transverse costal spines; 9, a non-adventitious ovicellate zooid (left) with 12 frontal-shield costae; 10, two semi-adventitious female zooids (possibly reparative). FIGURES 11–13. Cribrilina (Juxtacribrilina) spp., showing costate frontal shields, vestigial medial ooecia andtransverse costae of dwarf ovicellate zooids.11, from Akkeshi Bay, Hokkaido,Japan; 12, from Commander Islands, Russia; 13, from Ketchikan, Alaska. Scale bars:5–7, 9, 11–13, 200 µm; 8, 10, 100 µm.