Hippoporella maderensis, Souto, Javier, Reverter-Gil, Oscar & Ostrovsky, Andrew N., 2014

Souto, Javier, Reverter-Gil, Oscar & Ostrovsky, Andrew N., 2014, New species of Bryozoa from Madeira associated with rhodoliths, Zootaxa 3795 (2), pp. 135-151 : 146-147

Hippoporella maderensis n. sp.

( Figs 26–32 ; Table 5 )

Material examined. Holotype: MNCN –25.03/3869, 32º38’30.67’’ N, 16º49’47.49’’ W, 18 m, April 2011, on rhodoliths. Paratypes: MNCN –25.03/3870, 3871, 3872, 3873, NHMUK 2014.1.16.3, data as for holotype.

Etymology. From the geographical origin of the specimens.

Description. Colony encrusting, unilaminar, with multilaminar patches. Autozooids arranged irregularly, roughly oval to irregularly shaped, convex, separated by distinct sutures. Frontal shield thick and granular, becoming coarser with age, bordered by 14–16 large, distinct areolar pores. Suboral umbo conical, well-developed in older autozooids though frequently broken, basally forming a subquadrangular distal projection partly concealing proximal edge of zooidal orifice. Orifice relatively distant from distal edge of autozooid, its proximal edge midway along frontal surface, semicircular, slightly wider than long, with proximal edge slightly concave; distal edge with narrow lunula. Condyles smooth, with round tips, placed at about midlength of orifice. Articulated oral spines 5–6, stout, hollow, long, surrounding distal half of orifice. Each zooid normally bearing 1–4 triangular adventitious avicularia directed outwards, frequently placed around zooidal orifice; avicularia lacking in some zooids; newly developed avicularia projecting above frontal surface ( Fig. 29 ), becoming gradually immersed into thickening frontal shield in older zooids with rostrum at same level as frontal shield. Ovicell hyperstomial, noncleithral. Ooecium formed by distal kenozooid, with 2–5 large marginal pores. Ectoooecium gymnocystal, covered by nodular secondary calcification similar to that of frontal shield, often with small, central umbo. Ovicell opening oval, wider than long, placed above autozooidal orifice. Bases of four oral spines remaining in fertile zooids near entrance to brood cavity. Ancestrula not seen.

SD, Standard deviation; N, number of measurements.

Remarks. The specimens studied are similar to Hippoporella hippopus ( Smitt, 1868) , type species of the genus (see Hayward & Ryland 1999, Winston & Hayward 2012), in overall appearance including the frontal shield with marginal pores, the shape of the orifice and condyles, the oral spines and adventitious avicularia. The presence of these characters in both species justifies the inclusion of our specimens in Hippoporella . However, H. maderensis n. sp. differs from H. hippopus in: 1) having 5–6 oral spines, always visible, and although they may break, their bases and initial portions are always seen; 2) the orifice, clearly wider than long; 3) the triangular shape of the avicularia; 4) the well-developed conical umbo with its distal quadrangular projection. Hippoporella hippopus has two distal oral spines, the orifice is longer than wide, avicularia are oval or semielliptical, and the umbo, if present, is not well-developed and lacks a distal projection. The ooecium in H. hippopus is formed by a distal autozooid, not by the distal kenozooid as in H. maderensis n. sp.

The basal quadrangular projection of the suboral umbo in H. maderensis n. sp. may act as a ‘door stopper’ for the zooidal operculum, a function performed by the lyrula in some other ascophorans.

The validity of the genus Hippoporella has been questioned by several authors, who proposed its synonymy with Lepraliella (see Gordon 1984, 1993; Hayward & Ryland 1999). However, it is currently considered as a valid genus placed in the family Hippoporidridae (e.g. Winston & Hayward 2012; Bock & Hayward 2013b).

Figures

FIGURES 26 – 32. Hippoporella maderensis n. sp. 26, ovicellate and non-ovicellate zooids (holotype); 27, same, group of autozooids showing oral spines and suboral umbones; 28, same, autozooid showing a primary orifice with the bases of the oral spines, avicularia, and a suboral umbo with its distal projection; 29, same, close-up of the orifice showing the lunula, the basal part of the spines and the suboral umbo; note the avicularia projecting above the frontal surface; 30, same, detail showing the orifice of the ovicell and five oral spines; 31, inner view of the frontal shield (large condyles are clearly visible) (paratype 4); 32, distal zooidal wall showing basal parts of the oral spines and basal pore chambers (holotype).

Tables

TABLE 5. Measurements (in mm) of Hippoporella maderensis n. sp.

	Mean	SD	Minimum	Maximum	N
Autozooid length	0.416	0.0341	0.375	0.470	11
Autozooid width	0.341	0.0668	0.224	0.461	11
Orifice length	0.097	0.0090	0.082	0.109	8
Orifice width	0.114	0.0090	0.102	0.131	8
Avicularium length	0.080	0.0109	0.067	0.098	16
Avicularium width	0.042	0.0059	0.032	0.054	16
Ovicell length	0.122	0.0085	0.113	0.133	5
Ovicell width	0.203	0.0183	0.186	0.225	5