Porella

Souto, Javier, Berning, Björn & Ostrovsky, Andrew N., 2016, Systematics and diversity of deep-water Cheilostomata (Bryozoa) from Galicia Bank (NE Atlantic), Zootaxa 4067 (4), pp. 401-459 : 431-432

Porella sp.

( Figs 74, 75 )

Material examined. MNCN 25.03/3955, locality DR04; MNCN 25.03/3956, locality DR05.

Description. Colony encrusting, unilaminar, pluri- to multiserial, forming small patches. Zooids elongate-oval to hexagonal, often widest midlength, separated by shallow grooves or narrow ridges. Frontal shield slightly convex, producing a peristome of 2 low flaps lateral to orifice and incorporating suboral avicularium; surface nodular, imperforate except for single row of large areolar pores along zooecial margins and communication pore(s) on avicularian cystid. Orifice suborbicular, distal margin with 2 oral spines; condyles not visible, lyrula very short but almost as broad as proximal orificial margin, anvil-shaped.

Avicularium adventitious, single, suboral, small, oval, situated within peristome and directly abutting lyrula, oriented perpendicular to it.

Ovicells and ancestrula not observed.

Remarks. Although general zooidal morphology suggests that these specimens belong to the genus Porella , the absence of important characters such as the ovicell compels us to leave the species in open nomenclature. Vague similarities in autozooidal morphology exist between the encrusting Porella concinna (Busk, 1854) , nominally ranging from the western Mediterranean to Norway (Hayward & Ryland 1999, p. 160), although we cannot rule out the possibility that the encrusting colonies from Galicia Bank develop an erect colony part during astogeny. A distinctive character in the present specimens is certainly the short but extremely broad lyrula.

Porella sp. was recovered from two stations at 1099 and 1288 m depth.

Figures

FIGURES 74, 75. Porella sp., respectively showing part of fractured colony and zooidal orifice (MNCN 25.03 / 3955, 3956).