Cauloramphus multispinosus, Grischenko & Dick & Mawatari, 2007

Grischenko, Andrei V., Dick, Matthew H. & Mawatari, Shunsuke F., 2007, Diversity and taxonomy of intertidal Bryozoa (Cheilostomata) at Akkeshi Bay, Hokkaido, Japan, Journal of Natural History 41 (17 - 20), pp. 1047-1161 : 1079-1081

Cauloramphus multispinosus new species

( Figure 11 )

Diagnosis

Zooids large, oval, demarcated by groove; opesia large, up to 85% of zooidal length; cryptocyst narrow, granulated; gymnocyst reduced, smooth; 20–26 spines around mural rim; distal spines long, heavy, straight or nearly so; proximal spines very thin, sharp, curved and arched over opesia to meet nearly horizontally at midline; avicularia not observed and may be absent in this species; ancestrula tatiform.

Etymology

The species name refers to the unusually large number of spines.

Material examined

Holotype: KAI, two colonies on rock (NHM 2006.2.27.36). Paratypes: KAI, four colony fragments (NHM 2006.2.27.37); KAI, colony on rock (NHM 2006.2.27.38); KAI, colony on rock (NHM 2006.2.27.39); KAI, ancestrular colony on rock (NHM 2006.2.27.40). Additional material: 221 specimens; also several colonies on stones from Oshoro Bay , Hokkaido, Sea of Japan .

Description

Colony unilaminar, encrusting, coherent, forming extensive irregular patches up to 4 cm in maximum dimension, yellow to tan when alive. Zooids ( Figure 11A–F ) large, oval or rounded-hexagonal, occasionally tapering or pyriform, 0.55–0.98 mm long (0.75¡ 0.10 mm), 0.37–0.55 mm wide (0.46¡ 0.04 mm), demarcated by a deep, narrow groove. Mural rim sharp and comprises the boundary between smooth gymnocyst and granulated cryptocyst. Cryptocyst ( Figure 11D, E ) narrow, steep distally and laterally, sloping proximally, coarsely granulated. Gymnocyst reduced, narrow, smooth; sometimes evident laterally or elongated proximally, tapering between adjacent zooids. Opesia ( Figure 11D, E ) oval, widest in middle, 0.50–0.68 mm long (0.57¡ 0.04 mm), 0.27–0.35 mm wide (0.31¡ 0.02 mm), rarely with straight proximal margin, occupying 70–85% of zooidal length. Mural rim with 20–26 spines ( Figure 11B, C ); three pairs orificial spines straight, very long (up to 0.40 mm), hollow, thick, blunt, with enlarged cylindrical bases, the most proximal pair almost perpendicular or slightly tilted over opesia, the two distal pairs angling slightly forward; 14–20 opesial spines very thin, sharp, strongly curved over opesia, meeting almost horizontally in midline. Avicularia not observed. Embryos brooded endozooidally; fertile zooids have a small kenozooidal ooecium ( Figure 11D, E ) comprising the sharp mural rim distal to the orifice, usually with a tiny round or slit-like pore in midline. Six pore chambers in each lateral wall and two in distal wall. Ancestrula tatiform, oval, 0.50 mm long by 0.39 mm wide, basal wall with central uncalcified window, opesia large, oval, 0.38 mm long by 0.26 mm wide, surrounded by 16 spines (six hollow distal spines with enlarged bases, 6–10 thin proximal spines, curved over opesia). Ancestrula ( Figure 11F ) buds triplet of small zooids distally and distolaterally, with 16–20 spines each, and is eventually surrounded by six or seven zooids.

Remarks

Cauloramphus multispinosus is distinguishable from congeners by the large size of zooids; large number of thin, curved spines (up to 26) forming a tight, neat basket; and the apparent absence of avicularia. Northeastern Pacific C. spectabilis Dick and Ross, 1988 has up to 24 spines, but differs in having four pairs of heavy orificial spines, thicker opesial spines, longpedunculate avicularia, and smaller zooids, not exceeding 0.65 mm in length. Cauloramphus pseudospinifer Androsova, 1958 has up to 23 spines, but compared to C. multispinosus , there is less difference in thickness between orificial and opesial spines; the opesial spines are thicker; and there are thick, pedunculate avicularia (see Dick et al. 2005, Figure 3G, H ).

Distribution

Cauloramphus multispinosus is at present known from Akkeshi and Oshoro Bays, Hokkaido.

Figures

Figure 3. Electra korobokkura Nikulina, 2006. (A–C) NHM 2006.2.27.1; (D) NHM 2006.2.27.2. (A) Colony fragment with uniserial branches; (B) colony fragment with anastomosing, multiserial branches; (C) zooids without spinous processes; (D) zooids with spinous processes. All unbleached. Scale bars: 2 mm (A, B); 1 mm (C); 0.5 mm (D).

Figure 11. Cauloramphus multispinosus n. sp. (A) NHM 2006.2.27.36; (B, C) NHM 2006.2.27.38; (D, E) NHM 2006.2.27.37; (F) NHM 2006.2.27.40. (A) Colony margin with developing zooids, unbleached; (B) group of autozooids, unbleached; (C) close up of zooids showing details of distal erect spines and thin proximal spines strongly curved and arched over opesia, unbleached; (D) autozooids with variable form of proximal gymnocyst, bleached; (E) close up of zooids, unbleached; (F) ancestrula surrounded by periancestrular zooids, bleached. Scale bars: 0.5 mm.