Raymondcia klugei ( Gontar, 1982 )

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 : 1111-1112

Raymondcia klugei ( Gontar, 1982)

( Figure 25 )

Porella klugei Gontar 1982, p 549 , Figure 2-1 .

Material examined

ANC, young colony on rock (NHM 2006.2.27.6), two ancestrular colonies on rock (NHM 2006.2.27.7), extensive colony on rock (NHM 2006.2.27.8), colony on rock (NHM 2006.2.27.66). Additional material: 88 specimens.

Description

Colony encrusting, unilaminar, coherent, forming circular patches up to 4 cm across; orange, dark red or light violet when alive. Zooids ( Figure 25B ) hexagonal, oval, or pyriform, 0.47–0.65 mm long (0.57¡ 0.05 mm), 0.30–0.45 mm wide (0.38¡ 0.04 mm), usually with very irregular boundaries, separated by undulating suture line. Frontal wall slightly convex to inflated, finely granulated, with five or six areolar pores along each lateral margin and additional large, infundibuliform pores in the central region. With age, outer pore openings became enlarged and frontal wall appears reticulate, with rounded ridges between pores. In some colonies, frontal wall rises to a prominent, conical median suboral umbo ( Figure 25C ). Orifice circular to irregularly oval, 0.13–0.17 mm long (0.15¡ 0.02 mm), 0.14–0.19 mm wide (0.17¡ 0.01 mm), with a thin marginal rim; condyles and lyrula lacking. Secondary orifice cormidial, usually comprising four sectors, including contributions of frontal wall from the distal and lateral zooids, with distinct sutures between sectors. With increasing secondary calcification, the low peristome becomes irregular. A small, oval median suboral avicularium ( Figure 25B, D, E ) abuts the primary orifice; with increasing secondary calcification it comes to lie within peristome, orientated perpendicularly, or nearly so, to colony surface, hidden from frontal view; mandible semicircular, with complete cross-bar. Avicularian chamber small, crescentic, completely immersed with age; avicularium occasionally lacking. Spines and ovicells lacking. Zooids with two distal and four lateral basal pore chambers. Ancestrula not observed; obscured by ancestrular complex ( Figure 25F ) of heavily calcified zooids smaller than astogenetically mature zooids, often overgrown by layer of irregularly orientated, frontally budded zooids.

Remarks

The taxonomic position of this species is unclear. It does not belong in Porella , as originally placed, because that genus is characterized by having an ovicell and an umbonuloid frontal shield with marginal areolae only, although spines and lyrula may be lacking and the condyles greatly reduced ( Hayward and Ryland 1999). The cormidial secondary orifice, with contributions from the lateral and distal zooids, is very similar to that of Raymondcia ( Soule et al. 1995) ; Raymondcia also has a median suboral avicularium. However, characters of Raymondcia as the genus is now defined include lyrula, condyles, and ovicell. Although the definitions of some genera (e.g. Porella ) encompass variation in the presence or degree of development of a lyrula and condyles, inferred loss of the ovicell is problematic; we are not aware of any lepraliomorph genus in which some species have ovicells and others brood internally. Nonetheless, the overall resemblance of Raymondcia klugei (Gontar) to Raymondcia rigida (Lorenz) is remarkable. Since we were unable to observe embryos internally in any colonies of R. klugei , it is unknown whether this species really lacks ovicells and broods internally. As an alternative explanation for the absence of ovicells in our specimens, it might be that conditions in the intertidal zone of Akkeshi Bay are suitable for growth, but not for reproduction. Such a situation would occur, for example, if colonies reproduced only in relatively deep water, but recruits could survive intertidally.

Distribution

This species was originally described from Ivanovskogo Cape, Kunashir Island, southern Kuril Islands. Akkeshi Bay is the second known locality.

Figures

Figure 2. Dendrogram (below) showing similarity of sampling localities based on species presence/absence, and a map (above) showing the geographical distribution of three groups of sampling localities (circled) that are less than 70% similar in species composition between groups.

Figure 25. Raymondcia klugei (Gontar, 1982). (A, C) NHM 2006.2.27.66; (B) NHM2006.2.27.6; (D) NHM 2006.2.27.8; (E) ZIRAS 2/44556; (F) NHM 2006.2.27.7. (A) Colony margin with developing zooids; (B) immature zooids; (C) mucronate autozooids, lateral view; (D) distolateral view of autozooids showing suboral avicularia tilted inside; (E) autozooids, paratype specimen; (F) ancestrular region. Scale bars: 0.5 mm (A, E, F); 0.4 mm (B–D).