Thalamoporella rozieri ( Audouin, 1826 )

Harmelin, Jean-Georges, 2014, Alien bryozoans in the eastern Mediterranean Sea — new records from the coast of Lebanon, Zootaxa 3893 (3), pp. 301-338 : 307-309

Thalamoporella rozieri ( Audouin, 1826)

( Fig. 2 A–F; Tables 3 , 4 )

Flustra rozieri Audouin, 1826: 239 [ Savigny 1817: pl. 8, fig. 9.].

Thalamoporella rozieri: Soule et al. 1987: 255 , fig. 1g; 1992: 26, fig. 39; d’Hondt 2006: 37;? Eitan 1972: 378, fig. 3.

Not: Thalamoporella rozieri: Levinsen 1909: 181 ; Waters 1909: 141, pl. 15, figs 12–15; Harmer 1926: 292, pl. 19, figs 3–13; Powell & Cook 1966: 53–59; Prenant & Bobin 1966: 353, fig. 116.

? Thalamoporella evelinae Marcus, 1939: 129 , pl. 7, figs 8A,B; Soule & Soule 1964: 195, figs 1–2; Soule et al. 1992: 28, figs 41–44.

Material examined. Specimens from Lebanon: Stn 6C, 2 colonies on empty shells. Other material examined: 1) Several colonies identified as T. rozieri , India, south Kerala, Chowara, on Perna shells, 3 November 2010 (JGH coll.); 2) Photos of T. evelinae from São Paulo, Brazil, sent by Leandro Manzoni Vieira.

Description. Colony encrusting, unilamellar. Autozooids subquadrangular or elongate- hexagonal. Orifice with poster smooth and concave in young zooids, granular and more rectilinear in the middle part in older zooids, with lateral shoulders ending with small digitate condyles. Paired adoral tubercles relatively large and conical, or smaller and rounded. Opesiules slightly uneven in size, with basal insertions forming two uneven open hooks distally directed or one hook open and a smaller curved mark. Ooecium relatively frequent, large, broader than long, aperture large and forming a gothic arch. Maternal orifice with proximal edge concave and 2 distally directed knob-shaped condyles at the corners. Sclerites medium-sized callipers and compasses. Ancestrula similar in shape to older autozooids but with smaller orifice (L = 110 µm, W = 100 µm; data from Indian specimens).

Remarks. When Audouin (1826) formally named the specimen beautifully pictured by Savigny (1817) as flustra ? Rozieri , he did not indicate whether it came from the Mediterranean or the Red Sea. The original picture shows in great detail a colony bearing many large ooecia, oval orifices with prominent, rounded, adoral tubercles, and no avicularia. Soule et al. (1987) considered that this lack of avicularia in Savigny's picture was not an omission but a diagnostic feature at species level. Considering that Savigny's collection is most probably lost (d’Hondt 2006), Soule et al. (1992) selected a neotype (BMNH 1965.2.4.5) with large ovicells, prominent adoral tubercles and no avicularia among specimens collected by P.L. Cook at Massawa (Red Sea, Eritrea), thus not far from the Red Sea localities that could have been sampled by Savigny. Therefore, records of specimens with avicularia are rejected from the synonymy of T. rozieri (e.g. Levinsen 1909; Waters 1909; Harmer 1926; Powell & Cook 1966).

Surprisingly, although Flustra rozieri is the type-species of the genus Thalamoporella , Savigny's drawing and the description and figures of the neotype by Soule et al. (1992) are the only reliable sources of morphological data on this species. Abundant material collected on Perna shells from the west coast of India (Chowara, S Kerala), morphologically similar in many respects to the neotype of T. rozieri and to the Lebanese specimens, has enabled assessment of the morphological variability of T. rozieri . The main differences ( Tables 4 , 5 ) concern the orificial region, particularly the adoral tubercles, which are large, raised and conical in the neotype, medium-sized in the specimens from Kerala and smaller in the Mediterranean colonies. The proximal edge of the orifice (poster) is more deeply curved in the neotype while it varies from concave to straight with lateral shoulders in the Indian and Mediterranean specimens. Larger orifices are also noted in the Mediterranean specimens. However, the sizes of the orifices and the tubercles are, at least to some extent, ontogenetically related. Orifices of young zooids (near the growing margin) are larger than those of older, more calcified zooids. In contrast, the adoral tubercles increase in size from the growing margin to the centre of the colony, as observed in the material from Kerala. Therefore, the observed deviation of the Lebanese specimens from the neotype for this character may owe to their status as young, poorly calcified colonies. The relative size of ooecia may also differ between colonies of different origins.

Thalamoporella evelinae Marcus, 1939 is closely related to T. rozieri in all features except the shape of the basal insertions, which can form a transverse line in the former ( Marcus 1939, fig. 8B; Soule et al. 1992, fig. 44). The adoral tubercules are relatively small in the specimens depicted by Marcus (1939) and Soule et al. (1992), but are larger in a specimen from Sao Paulo (photos by L.M. Vieira). The taxonomic relationships between T. rozieri and T. evelinae need to be re-examined in significant samples for precise morphological and molecular analyses.

Figures

FIGURE 2. Thalamoporella rozieri (Audouin, 1826); A, B, F from Stn 6 C, Lebanon; C – E from south Kerala, India: A, maternal zooid with ooecium; B, non-ovicelled zooid; C, ovicelled and non-ovicelled zooids; D, four autozooids; E, basal insertions of opesiules; F, spicules and proximal edge of orifice. Scale bars: A – C, 100 µm; D, 200 µm; F, 20 µm.

Tables

TABLE 3. Thalamoporella rozieri: morphological characters of colonies from Eritrea (neotype, data from Soule et al. 1992), SW India and Lebanon. S, small; M, medium; L, large.

Characters	Red Sea Eritrea (neotype)	Indian Ocean S Kerala	E Mediterranean Lebanon
Growth form	encrusting	encrusting	Encrusting
Orifice: poster	deeply arcuate	Concave to straight, with shoulders	Concave to straight, with shoulders
Orifice: condyles	distinct, hooked, M	distinct, pointed, S	distinct, pointed, S
Adoral tubercles	Conical, L	Conical, M-L	Rounded, S
Opesiules: size	Uneven, M	Uneven, M	Uneven, M
Basal insertions	1-2 open hooks	1 open hook + 1 curved bar	2 open hooks or 1 open hook + 1 curved bar
Ovicell size	L, broad	L, broad	L, medium broad
Ratio Ov W / Az W	1.5	1.4	1.3
Spicules	S-M compasses, C- shaped calipers	S-M compasses, C-shaped calipers	S-M compasses, C-shaped calipers
Avicularia	no	no	no

TABLE 4. Thalamoporella rozieri: morphometric characters of colonies from Eritrea, Red Sea (neotype, data from Soule et al. 1992), SW India and Lebanon; measurements in µm.

	Red Sea Neotype			Indian Ocean S Kerala				E Mediterranean Lebanon
	X	Range	N	X	SD	Range	N	X	SD	Range	N
Az L	544	500–620	17	617	44	560–705	30	638	48	555–680	12
Az W	341	290–400	17	308	32	245–365	30	375	41	320–435	12
Or L	-	-	-	142	5	135–155	30	163	8	150–170	12
Or W	-	-	-	142	6	125–155	30	167	7	160–170	12
Ov L	450	-	7	360	21	325–410	30	384	30	335–415	6
Ov W	523	-	7	442	27	390–500	30	489	11	480–510	6