Thalamoporella harmelini Soule, Soule & Chaney, 1999

Harmelin, Jean-Georges, 2014, Alien bryozoans in the eastern Mediterranean Sea — new records from the coast of Lebanon, Zootaxa 3893 (3), pp. 301-338 : 305

Thalamoporella harmelini Soule, Soule & Chaney, 1999

( Fig. 1 A–E; Table 2 )

Thalamoporella harmelini Soule, Soule & Chaney, 1999: 35 , figs 51–53.

Thalamoporella gothica var. indica: Powell 1969a: 159 , fig. 3; d’Hondt 1988: 193, figs 3–6. Non Thalamoporella indica Hincks, 1880: 380 , pl. 16, fig. 1.

Thalamoporella indica: Chaney et al. 1989: 348 (part); Bitar & Kouli-Bitar 2001: 72. Non Thalamoporella indica Hincks, 1880: 380 , pl. 16, fig. 1.

Material examined. Specimens from Lebanon: 1) Stn 13A, a large (now fragmented), erect, bilaminar, foliaceous colony from which a fragment sent by JGH to D. Soule and J. Soule was designated as the holotype of T. harmelini [ AHF (SBMNH-AHF) Bryozoan No. 248: Soule, Soule & Chaney 1999]; the rest of this colony is deposited at MNHN and NHMUK; 2) Stn 13B, a medium-sized erect, bilaminar, foliaceous colony; 3) Stn 15A, 3 encrusting unilaminar colonies on shells.

Description. Colony encrusting, unilamellar (young stages), or ‘eschariform’, i.e. with irregularly anastomosing, bilamellar, foliaceous ramifications (older stages). Autozooids quadrate, arranged in linear rows. Frontal cryptocyst finely granular, with 30–60 small pseudopores, depressed at level of opesiules; these paired, bearing some small denticles on their distal margin, unevenly sized, the larger descending to the basal wall where its insertion forms a closed loop downwardly oriented and variably sized within colonies. Orifice generally as long as broad, poster concave, slightly granular, with two minute hooked condyles at each end, an inner, distal rim corresponding to proximal border of distally adjacent zooid. Paired adoral tubercles present, larger in older zooids. Avicularia relatively small (Az L/Av L = 1.4: ratio of mean values), longer than broad, rostrum pointed, raised on a bulging chamber at an angle of about 30°, sides a little convex, opesia semicircular, proximal cryptocyst with some tiny granules. Spicules are medium-sized callipers and compasses. Ovicells lacking in the holotype and other specimens.

Remarks. Thalamoporella harmelini belongs to a group of species with acute avicularian mandibles ( Soule et al. 1999). It is seemingly closely related to Thalamoporella floridana ( Osburn, 1914) from the eastern Caribbean and Florida, Thalamoporella spinosa Chaney, Soule & Soule, 1989 from the Indian Ocean and Persian Gulf, and Thalamoporella labiata ( Levinsen, 1909) from Taiwan Strait. These four species have similarly shaped pointed avicularia, single closed-loop basal insertions and apparently no ovicells. Both T. spinosa and T. labiata differ from T. harmelini in having orifices with a convex proximal lip. In T. floridana , the basal-loop insertions are clearly shorter than in T. harmelini and the proximal lip of the orifice is smooth instead of being granular.

The genus Thalamoporella includes 46 Recent species ( Bock 2014), distributed in warm to warm-temperate waters of the Indo-Pacific realm (80%) and the W and E Atlantic (17.4%). Thalamoporella harmelini was the only Thalamoporella species recorded in the Mediterranean, exclusively from the Levant coasts. The figures and descriptions of specimens recorded from Israel as Thalamoporella gothica (Busk) var. indica Hincks, 1880 by Powell (1969a) and d’Hondt (1988) suggest that they are conspecific with T. harmelini . In particular, as pointed out by Powell (1969a), they have acute avicularia, no ovicells and their colonies are either encrusting or bilamellarfoliaceous. The occurrence of this species in Israel was confirmed by Noga Sokolover (pers. comm. 12 December 2013). Two other records of T. indica from the Eastern Mediterranean ( Chaney et al. 1989; Bitar & Kouli-Bitar 2001) correspond to Lebanese specimens from the present collection, assigned here to T. harmelini . The known geographical range of T. harmelini is restricted to a limited portion of the Levantine basin, from Tel Aviv to Beirut, i.e. in the vicinity of large commercial ports, close to the Suez Canal. Conversely, despite large-scale sampling it was not recorded at other sites along the Lebanese coast. It is a typical cryptogenic species but its distribution argues for an exotic origin.

Figures

FIGURE 1. Thalamoporella harmelini Soule, Soule & Chaney, 1999, Lebanon, Stn 13 A (from same colony as holotype): A, young part of colony with several autozooids and an avicularium; B, distal part of autozooid (slightly angled view), paired adoral tubercles and orifice with hooked condyles and granular proximal edge; C, avicularium and distal part of autozooid; D, basal insertion of the larger opesiule in two autozooids, each forming a closed loop; E, spicules. Scale bars: A, C, 100 µm; B, E, 50 µm.

Tables

TABLE 2. Thalamoporella harmelini, morphometrics of three colonies from Stns 13 A, 13 B, 15 A.

T. harmelini	X	SD	Range	N
Az L	563	51	450–650	30
Az W	293	31	245–365	30
Or L	144	14	120–165	28
Or W	143	9	120–155	28
Av L	390	51	315–510	25
Av W	211	60	140–330	25