Stephanotheca arrogata ( Waters, 1879 ) Waters, 1879

Reverter-Gil, Oscar, Souto, Javier & Fernández-Pulpeiro, Eugenio, 2012, A new genus of Lanceoporidae (Bryozoa, Cheilostomata), Zootaxa 3339, pp. 1-29 : 25-27

Stephanotheca arrogata ( Waters, 1879) n. comb.

( Figs 62–67 ; Table 9)

Lepralia arrogata Waters, 1879: 39 , pl. 8, fig. 1.

Schizomavella arrogata (Waters) : Gautier, 1962: 131; Zabala 1986: 468, fig. 158; Zabala & Maluquer 1988: 130, fig. 297. Schizomavella monoecensis (Calvet) : Poluzzi & Rosso 1988: 91, pl. 4, fig. 3.

Material examined. Lectotype (selected here): MM 2852: Naples, Waters Coll. Paralectotypes (selected here): MM 2960: Naples, Waters Coll.; MM 2961: Naples, egg ovarium, slide, Waters Coll.; MM 2962, 2963, 2964: Naples, Waters Coll.; MM 2965: Naples, Opercula on slide, Waters Coll.; MM 2966: Naples, slide of sections, Waters Coll.; MM 2967, 2969: Naples, Waters Coll.; MM 2970: Capri, opercula and mandibles on slide, Waters Coll.; MM 10851: Naples, Waters Coll. Other material Examined: MM 2971: Villafranche, opercula on slide, Waters Coll.

Description. Colony encrusting, unilaminar to multilaminar, forming irregular crusts, light yellow in life. Autozooids in regular series in unilaminar colonies, irregularly arranged in multilaminar colonies; polygonal, irregularly shaped, separated by fine raised sutures; frontal shield slightly convex, initially smooth but soon covered by small rounded conical nodules, evenly perforated by small, circular pseudopores; periorbital area imperforate and slightly raised; marginal pores elongate and more conspicuous in older zooids. Primary orifice subtriangular, slightly longer than wide; anter forming a wide arch projecting distally; lateral edges oblique and rather straight; poster with a wide U-shaped sinus, occupying one third of the proximal edge; a pair of large condyles, serrated in the proximal half. Oral spines absent. One central avicularium, large, elongate-triangular, distally rounded, occupying nearly the entire zooid length; mandible triangular, proximally directed, sometimes following the zooidal axis or frequently turned to one side; crossbar slender, complete; distal opesia circular, palatal foramen large, subtriangular. Ovicell subconical, prominent to subimmersed; central area flat, transversely oval, evenly perforated by irregularly rounded pseudopores; secondary calcification smooth laterally, projecting frontally in a crown of stout nodules, complete or incomplete proximally, often with a distinct proximal suture. Additionally, the ovicell can be covered by secondary calcification encroaching from adjacent zooids. Primary orifice of ovicellate zooids dimorphic, wider and with shallower sinus, concealed by the ovicell opening; this inclined at an angle, formed by the concave proximal margin of the ooecium, extending to proximolateral corners of zooidal orifice; closed by zooidal operculum. Ancestrula unknown.

TABLE 9. Measurements (in mm) of Stephanotheca arrogata ( Waters, 1879) n. comb. (lectotype and one paralectotype). SD, Standard deviation; N, number of measurements.

Remarks. This species was originally described by Waters (1879) from material collected in Naples. Gautier (1962) transferred it to Schizomavella , and reported it from the Strait of Sicily.

Of all the species included in the S. ochracea group, this is probably the most distinct. Its orifice tends to be subtriangular, especially evident in uncleaned material with opercula of dark brown colour. Its sinus is wider, being U-shaped in the type material though in other specimens it is more triangular. The avicularium is large, triangular to lanceolate, occupying a great part of the zooidal length; therefore, it is very different from the rest of the species of the genus. Only S. triangulata n. sp. also has triangular avicularia but these are smaller and placed more proximally. The ovicell is also very peculiar, showing an almost subconical shape with a crown of very prominent nodules, seldom interrupted over the ovicell opening, while the rest of the peripheral secondary calcification is rather even.

Stephanotheca arrogata seems to be an exclusively Mediterranean species, reported from Naples, the southern part of the Tyrrhenian Sea, Banyuls (southern France) and the Alboran Sea. A record from the Ionian Sea by Poluzzi & Rosso (1988) as S. monoecensis could also correspond to this species.

Figures

FIGURES 62 – 67. Stephanotheca arrogata (Waters, 1879) n. comb. 62, view of the colony with ovicellate zooids (lectotype: MM 2852); 63, same, primary orifice; 64, same, autozooids with avicularia; 65, same, ovicellate and non-ovicellate zooids; note the cormidial secondary calcification covering the ovicells, contributed by several zooids; 66, same, ovicellate zooid; 67, view of the colony with ovicellate zooids (paralectotype: MM 2969).