Schizoretepora solanderia ( Risso, 1826 )

Madurell, Teresa, Jones, Mary Spencer & Zabala, Mikel, 2019, Revision of the Genus Schizoretepora (Bryozoa, Cheilostomatida) from the Atlantic-Mediterranean region, European Journal of Taxonomy 536, pp. 1-33 : 10-13

Schizoretepora solanderia ( Risso, 1826)

Fig. 5 , Table 2

Retepora solanderia Risso, 1826: 344 .

Retepora solanderia – Waters 1895: 264, pl. VI, figs 1–4. — Calvet 1902: 35, pl. 2, figs 5–8.

Schizoretepora solanderia – Gautier 1962: 237. — Zabala & Maluquer 1988: 399, figs 395–396. — Rosso 2003: 17, fig.1. — Rosso et al. 2010: 604.

Material examined

TUNISIA • 10 fragments; Tabarka , st. 19; 86 m deep; Waters leg.; coll. Jullien 152; MNHN-IB- 2008-2947 .

SPAIN • 2 colonies; Menorca Channel , st. 72; 115 m deep; Indemares 6 exped.; MZB 2014-1486 • 3 colonies; Menorca Channel , st. 89; 140–258 m deep; Indemares 4 exped.; MZB 2014-1471 • 1 colony; Menorca Channel , st. 90; same collection data as for preceding but 127–257 m deep; MZB 2014-5758 .

Description

Colony erect, irregularly branched in one plane, fan-shaped, vinculariform (not fenestrate), white, pink or orange-colored. Frontal faces bearing autozooids, abfrontal faces consisting of sheets of kenozooids.

Branches thick, with on average four (2–5) rows of autozooids arranged quincuncially, with a serrate profile owing to the presence of giant vicarious avicularia (see below) ( Fig. 5A ).

Autozooids hexagonal, longer than wide, convex, separated by distinct sutures. Frontal slightly rugose, with two areolae, placed on the proximal part of the zooid ( Fig. 5C ).

Primary orifice always obscured by the peristome, longer than wide, distal rim with rounded denticles, proximal border with U-shaped sinus flanked by short, smooth and wide condyles ( Fig. 5B ). Peristome well-developed, forming tubular high collar; with drop-shaped long spiramen and upper slit cutting it in two plates (young zooids) ( Fig. 5C ), becoming shorter and smoother in older zooids ( Fig. 5D ).

More commonly four (5 to 6) long oral spines, articulated and carinated ( Fig. 5E ), with basal parts thickly fused in young zooids ( Fig. 5C ), only two and gradually disappearing in older zooids ( Fig. 5D ).

Two types of frontal triangular avicularia. Adventitious large avicularia on raised cystid, laterally directed, irregularly present, placed on the median line of frontal surface ( Fig. 5D ). Giant vicariant avicularia hooked, regularly present on lateral sides of branches, facing upwards and distolaterally directed, sometimes with up to three piling cystids ( Fig. 5F ). Both types with robust crossbar and lacking columella.

Ovicell typically globular, slightly longer than wide, hyperstomial in young zooids, immersed with secondary calcification, surface smooth, imperforate, with large central fissure, widening at base, noncleithral ( Fig. 5G ).

Abfrontal layer with two rows of large, rugose, polygonal kenozooids, with one to three pores and raised sutures. Abfrontal avicularia large, acute, triangular, sporadically present, more frequent near base of colony ( Fig. 5H ).

Remarks

Until now, four oral spines have consistently been reported for S. solanderia ( Calvet 1902; Gautier 1962). As shown in our specimens, however, the number of spines changes with ontogenetic development, with a higher number of spines on apical autozooids (up to six spines). Schizoretepora solanderia is easily distinguished from all other species of Schizoretepora by the well-developed peristome forming a high collar with a drop-like spiramen. Schizoretepora solanderia is rather common in the Mediterranean and north-eastern Atlantic on coralligenous and detritic bottoms from 30 to 300 m deep.

Figures

Fig. 5. Schizoretepora solanderia (Risso, 1826), Menorca Channel (A–B, D, G–H: MZB 2014-1471; C, E–F: MZB 2014-1486). A. Colony view. B. Detail of aperture. C. Growing margin with autozooids showing up to six spines. D. Older ovicellate autozooids with giant vicarious avicularia. E. Detail of articulated and carenated spines. F. Marginal avicularia showing nested piling of cystids. G. Details of ovicell. H. Abfrontal view with avicularia.

Tables

Table 2. Measurements of Schizoretepora solanderia (Risso, 1826).

	N	MEAN	SD	MIN	MAX
TW	17	924	111	762	1164
Nz	17	3.2	0.4	3	4
AzL	44	473	43	355	565
AzW	39	279	30	222	337
ApL	12	102	20	79	145
ApW	19	108	10	91	130
OL	6	92	3	88	97
OW	6	89	7	79	97
VAL	25	205	41	144	321
VAW	24	102	11	80	118
AbAL	4	257	12	247	275
AbAW	3	108	14	99	124
OVL	18	204	19	162	229
OVW	17	191	15	161	214
Ns	50	3.6	1.4	2	6
Np	28	2	-	2	2
Np_Ab	11	3	0.8	3	4