Celleporaria

Harmelin, Jean-Georges, 2014, Alien bryozoans in the eastern Mediterranean Sea — new records from the coast of Lebanon, Zootaxa 3893 (3), pp. 301-338 : 316-317

Celleporaria sp. aff. brunnea ( Hincks, 1884)

( Fig. 6 A–C)

? Holoporella brunnea: Hastings 1930: 731 , pl. 16, figs 108–110; Osburn 1952: 496, pl. 62, figs 10–12.

? Celleporaria brunnea: Winston 1986: 12 , figs 19–22; Soule et al. 1995: 267, fig. 101; Canning-Clode et al. 2013: 2, figs 2A–C.

Celleporaria brunnea: Koçak 2007: 191 , fig. 2.

? Celleporaria aperta ( Hincks, 1882) : André et al. 2014: 181.

Material examined. Specimens from Lebanon: 1) Stn 14A, 1 colony on shell from a jetty block, Beirut, 3– 11 m. Other material examined: Turkey, Izmir, 2 m, on mussel, F. Koçak coll.; France, Arcachon Basin, specimens and SEM photos, M. Barrabes coll.

Description. Colony encrusting, multilamellar, dark grey when dry. Autozooids well calcified, unevenly oriented, with distal part (orifice and ovicell) prominent, frontal shield irregularly nodular, with 8–12 mediumsized marginal pseudopores, separated by low crests in heavily calcified zooids. Orifice variably sized according to calcification status of zooid, a little longer than broad on average [Or L, 167 ± 13 µm (135–180 µm, N = 16); Or W, 163 ± 14 µm (135–180 µm, N = 16)]; anter semicircular, poster with low, rounded sinus laterally bordered by more or less acutely triangular corners, condyles small, triangular; operculum brown. Two oral spines, long (260 µm), articulated with brown basal joint, very occasional and only near peripheral budding margin; basal scars not visible when spines lacking. Suboral avicularium small, placed on side of small, vertically raised umbo, with oval, finely serrated rostrum (6–8 teeth), dark-brown mandible and clear, opaque membranous area. Interzooidal avicularia rare, relatively small and variably sized [Av L, 231 ± 70 µm (170–340 µm, N = 5); Av W, 99 ± 16 µm (80–125 µm, N = 5)], parallel-sided, mandible with dark sclerite over entire width in proximal half, reduced to central column in distal half, proximal membranous area whitish, crossbar complete, without columella, distal palate medium-sized, rostral tip rounded distally with basal side slightly bulging. Ooecium widely open, frontal surface forming a narrow cap with uneven surface, occasionally bearing an avicularium.

Remarks. The single Lebanese specimen agrees closely with colonies from Turkey (Izmir Bay) assigned to C. brunnea by Koçak (2007). The only observed difference relates to the sinus, which is similarly shaped but broader in the former. The assignment of these Mediterranean colonies to C. brunnea , a Californian species, is disputable (L.M. Vieira, pers. comm. August 2014) despite some degree of morphological similarity concerning the primary orifice, the suboral avicularia, the interzooidal avicularia, the ooecium, and the occasional occurrence of two oral spines. In the specimen from Central California figured by Soule et al. (1995, fig. 101C) the primary orifice presents a sinus, which tends to be closed by horizontal digitations developed from its corners. In the Lebanese specimen, the sinus corners can also develop small digitations, which are curved or directed distally. The most evident differences pertain to the size of the sinus and the interzooidal avicularia: their frequency and size, and the width of the distal palate, which is larger in the Californian specimens (Winston 1986, fig. 22; Soule et al. 1995, fig. 101B).

In both Eastern Mediterranean localities where this species has been collected (Izmir Bay: Koçak 2007; Beirut airport: this paper), the habitat was artificial and strongly impacted by human activities. It is very likely that shipping is responsible for its introduction in this part of the Mediterranean. Celleporaria brunnea (or, more likely, an allied undescribed species according to L.M. Vieira, pers. comm. August 2014) was also recorded in the Western Mediterranean ( Italy: A. Occhipinti-Ambrogi, pers. comm. 1 June 2014) and in the NE Atlantic: Portugal, Cascais marina ( Canning-Clode et al. 2013). It was recently discovered in the Arcachon Basin, France and recorded as Celleporaria aperta (Hincks) ( André et al. 2014). These latter specimens differ from the Mediterranean ones in having interzooidal avicularia with a broader distal palate and the two orificial spines more frequent and their scars clearly visible.

The type locality of C. brunnea is Queen Charlotte Islands, British Columbia. It is one of the commonest species in California and Baja California ( Soule et al. 1995). The occurrence of C. brunnea in harbours, such as that of Los Angeles ( Soule & Soule 1981), may indicate a particular tolerance to chemical contaminants and a capacity for fouling.

Formal specific determination of the Mediterranean and Atlantic specimens will require thorough comparisons with the Pacific material of C. brunnea , including Hincks's type.

Figures

FIGURE 6. Celleporaria sp. aff. brunnea (Hincks, 1884), Lebanon, Stn 14 A: A, ovicelled and non-ovicelled zooid;. B, orifice and suboral adventitious avicularium; C, vicarious avicularium appressed against one side of an ooecium. Scale bars: A, C, 100 µm; B, 50 µm.