Stephanotheca watersi, Reverter-Gil, Oscar, Souto, Javier & Fernández-Pulpeiro, Eugenio, 2012

Reverter-Gil, Oscar, Souto, Javier & Fernández-Pulpeiro, Eugenio, 2012, A new genus of Lanceoporidae (Bryozoa, Cheilostomata), Zootaxa 3339, pp. 1-29 : 12-15

Stephanotheca watersi n. sp.

( Figs 2, 4, 7 , 26–30 ; Table 3 )

? Lepralia rudis Manzoni, 1869: 18 , pl. 1, fig. 2.

Schizoporella ambita Waters, 1889: 11 (part: only material from Naples).

Schizoporella ambita Waters : Calvet 1902: 46, pl. 2, figs 1, 2.

Schizomavella rudis (Manzoni) : Gautier 1962: 146 (part: not material from Balearics); Zabala 1986: 478, pl. 13, fig. E (not fig. 164); Zabala & Maluquer 1988: 132.

Not Schizoporella ambita Waters, 1889: 11 (part: Australian material).

Not Schizomavella rudis (Manzoni) : López de la Cuadra 1991: 232, pl. 27, figs F–G; Hayward & McKinney 2002: 61, figs 27 D–H.

Material examined. Holotype: MM 2845: Naples, Coll. Waters. Paratypes: MM 2928, MM 2932; MM 2934, MM 2939: Naples, Coll. Waters; MM 12478: Oran, 60 m, Coll. Waters. MNHN 2356 (part, colony on a gastropod shell): Bonifacio, Coll. Calvet; MNHN 4150: without locality, Coll. Calvet. MNHN 11141, MNHN 11142, MNHN 11144, MNHN 11145, MNHN 11146, MNHN 11147, MNHN 11148, MNHN 11149, MNHN 11193: Marseille, Coll. Gautier.

Etymology. This species is dedicated to A.W. Waters, who first recorded it.

Description. Colony encrusting, unilaminar, forming broad irregular crusts. Autozooids in regular linear series, sometimes alternating. Autozooids polygonal, often subrectangular, large, separated by fine raised sutures; transverse wall often curved. Frontal shield flat or slightly convex with a slightly granular surface, evenly perforated by small, circular pseudopores situated in funnel-shaped depressions that are demarcated by slightly raised ridges. Secondary calcification producing a scattered granulation and small depressions containing pores; marginal pores becoming areolate in older zooids. Periorbital region somewhat swelled, marked with small nodules or ridges. Primary orifice orbicular, wider than long, its distal edge projecting distally; poster almost entirely occupied by a wide, shallow sinus; condyles small, oval, serrate only along their inner half; denticles turned inwards. Oral spines absent. Suboral avicularia inconstant, often wanting in large areas of colony; occasionally replaced by a low mucro, difficult to see among the nodules surrounding the proximal edge of the zooidal orifice; avicularium oval, small, with slender, complete crossbar, semi-elliptical mandible proximally directed. Distance to the orifice smaller than avicularium length. Ovicell globular, prominent to subimmersed depending on thickness of secondary calcification; ectooecium to a large extent covered by coarsely nodular secondary calcification, with a circular crown of nodules surrounding the exposed central pseudoporous area, this subcircular, depressed, with more-or-less evenly distributed round, oval or irregular perforations that are larger in the periphery; nodular corona occasionally incomplete proximally; secondary calcification occasionally covering the entire pseudoporous area with only the pseudopores remaining exposed. Primary orifice of ovicellate zooids wider than non-ovicelled zooids, and with sinus shallower and broader. Opening of ovicell inclined at an angle, formed by the concave proximal margin of the ooecium, overarching the primary orifice and extending to its proximolateral corners; ovicell cleithral. Zooids with small uniporous septula, placed in rows parallel to basal wall.

SD, Standard deviation; N, number of measurements.

Remarks. As mentioned for the previous species, Waters (1889) described Schizoporella ambita from material collected at Green Point ( Australia), and also reported this species from Naples. The Naples material (MM 2845, MM 2928, MM 2932; MM 2934; see figs 27, 30) as well as a colony from Oran (MM 12478), despite showing several similarities with the original material of S. ambita , belongs to a different species. In fact, Canu & Bassler (1929) already doubted the conspecifity of the Australian and Mediterranean forms. Gautier (1962) studied Mediterranean material similar to that reported as S. ambita by Waters (1889) and by Calvet (1902); this author, following a suggestion by Lagaaij, referred to it as Schizomavella rudis ( Manzoni, 1869) , a fossil species, but it is doubtful if Gautier saw Waters’ or Manzoni’s original material.

Lepralia rudis was originally described by Manzoni (1869) from the Mid-Pliocene (Piacenzian) Monte Padova section (C. Pizzaferri pers. comm. 2009); the author also defined a presumed variant of this species — termed var. granulosa-foveolata — characterised by the structure of the frontal wall. The descriptions as well as the figures of both taxa are very imprecise, omitting several important details for adequate the characterization of the species; for instance, there is no mention of an avicularium and the ovicell is described as “ globoso-elongatis, suberectis, granulosis ”, while in the figure ( Manzoni 1869: pl. 1, fig. 2) the ovicell seems to be evenly perforated like the frontal shield of the autozooids. Finally, the original material of Manzoni no longer exists and the identity of this species accordingly remains unclear.

On the other hand, C. Pizzaferri (unpublished data) has collected many Mid-Pliocene specimens in the Monte Padova section of Castell’Arquato (Piacenza, north Italy). In this material it seems that two species can be distinguished; one of them exhibits a small suboral avicularium close to the orifice and can perhaps be compared with Recent colonies that have been attributed by recent authors to S. rudis . The other species exhibits a wider avicularium that is placed more proximally, and could be similar to S. monoecensis . One of these two species could correspond to the species described by Manzoni (1869) from the same location. Whatever the case, additional comparative studies of both the fossil and Recent material will be needed and the identity of the fossil material remains to be determined.

We recognize a new species, Stephanotheca watersi n. sp., for the Recent Mediterranean material previously referred to as S. ambita and S. rudis by Calvet (1902) and by Gautier (1962), respectively, and on material from Naples and Oran of the Waters collection. All specimens are extremely similar, therefore we have no doubt that they belong to the same species.

Stephanotheca watersi n. sp. differs from S. barrosoi by exhibiting an orbicular orifice that is clearly wider than long, with small condyles that are denticulate only in their inner half, while in the second species the orifice is elliptical, only slightly wider than long, and with larger condyles exhibiting well-defined denticulations on their entire edge. The avicularia are similar in size and shape in both species, although in S. barrosoi they are more frequent and located further away from the primary orifice. In addition, this species exhibits a vicarious avicularium, unknown in S. watersi . The ovicell is similar in both species, but while the nodular crown is often complete in S. watersi , in S. barrosoi is usually interrupted in its proximal part. Finally, S. watersi typically forms unilaminar colonies, while in S. barrosoi the colonies are multilaminar. Gautier (1962) pointed out that the colonies of S. rudis can also be multilaminar, but in his material all the colonies belonging to this species are unilaminar; only some Balearic specimens are actually multilaminar, but are referred here to as S. barrosoi .

We have not seen any ancestrulae in material of this species and none was described from the Recent material, as far as we know. In fossil material from the Pliocene Monte Padova section (Castell’Arquato area), which is perhaps similar to S. watersi , a tatiform ancestrula was found that had a suborbicular-oval opesia bordered by an indeterminate number of spines and no basal wall, was found (C. Pizzaferri, unpublished data).

The published literature is not very useful for establishing the geographic distribution of S. watersi unless accompanied by complete descriptions or figures. The record of S. rudis by Hayward & McKinney (2002) from Croatia does not correspond to the species described here. Among other differences, the zooidal orifice has a proximal edge with a shallow sinus flanked by two shoulders and smooth condyles, the ovicell seems to be uniformly perforated and it does not exhibit a dimorphic orifice. This record may represent an undescribed species of Schizomavella . The record by López de la Cuadra (1991) does not match this species either (see Reverter Gil & Fernández Pulpeiro 1995 and discussion of S. ochracea in the present paper).

Stephanotheca watersi n. sp. seems to be distributed mainly throughout the Western Mediterranean; its putative presence in other areas should be checked by examination the material upon which the records are based.

Figures

FIGURES 1 – 8. Ovicell development in Stephanotheca. 1, communication pore between the ooecium-producing zooid and the coelomic cavity of the ooecium (arrow) (S. barrosoi n. sp.). 2, calcification of ectooecium and beginning of the calcification of entooecium (S. watersi n. sp.). 3, calcified ooecial floor (S. ochracea n. comb.). 4, developing ooecia (S. watersi n. sp.). 5, developing ooecium (S. monoecensis n. comb.). 6, central suture of the ectooecium (arrow) (S. barrosoi n. sp.). 7, complete ovicell, ooecial floor, and a partially broken ovicell showing ectooecial pseudopores (S. watersi n. sp.). 8, secondary calcification growing over the central porous area (S. monoecensis n. comb.).

FIGURES 26 – 30. Stephanotheca watersi n. sp. 26, view of the colony with developing ooecia (paratype: MNHN 11148); 27, primary orifice (holotype: MM 2845); 28, primary orifice (paratype: MNHN 11141); 29, same, two ovicellate zooids; 30, view of the colony (holotype: MM 2845).

Tables

TABLE 3. Measurements (in mm) of Stephanotheca watersi n. sp. (holotype and three paratypes).

	Mean	SD	Minimum	Maximum	N
Autozooid length	0.589	0.0718	0.465	0.780	40
Autozooid width	0.433	0.0594	0.323	0.585	40
Orifice length	0.135	0.0104	0.113	0.161	40
Orifice width	0.144	0.0122	0.123	0.175	40
Adventitious avicularium length	0.078	0.0070	0.062	0.087	11
Adventitious avicularium width	0.066	0.0068	0.053	0.081	11
Ovicell length	0.300	0.0140	0.283	0.327	9
Ovicell width	0.368	0.0262	0.334	0.411	9
Ovicell orifice length	0.116	0.0029	0.113	0.119	4
Ovicell orifice width	0.175	0.0048	0.169	0.179	4
Pseudorous area diameter	0.170	0.0137	0.152	0.194	9