Parasmittina talismani ( Calvet, 1906 ) Reverter-Gil & Fernández-Pulpeiro, 2007

Reverter-Gil, Oscar & Fernández-Pulpeiro, Eugenio, 2007, Species of genus Schizotheca Hincks (Bryozoa, Cheilostomata) described in the Atlantic-Mediterranean region, with notes on some species of Parasmittina Osburn, Journal of Natural History 41 (29 - 32), pp. 1929-1953 : 1931-1935

Parasmittina talismani ( Calvet, 1906) comb. nov.

( Figure 1 )

Schizotheca talismani Calvet 1906, p 429 , Plate 28, Figure 5 .

Material examined

Holotype (by original designation): MNHN-299 and MNHN-1038: Talisman 1883 . st. 105. 110–180 m. Ilot Branco, Cape Verde. Calvet Coll. Both samples correspond to the single colony originally described by Calvet (1906).

Other material. MNHN-1037: Talisman 1883 . 20– 25 m. Ilot Branco, Cape Verde. Calvet Coll. MOM-42 0822: st. 1203, 1901. 91 m. Calvet Coll .

Description

Colony encrusting, unilaminar. Autozooids quadrangular, arranged in linear series and separated by marked sutures; frontal surface flat or slightly convex, smooth or slightly granular, centrally imperforate, with numerous marginal areolar pores, very conspicuous.

Primary orifice orbicular, deeply immersed by secondary calcification and difficult to observe, situated very distally; lyrula very wide (0.08–0.09 mm) with a straight edge and sharp-pointed lateral extremes facing two small condyles. Peristome well developed, with two thick proximal projections that define a deep rounded median groove that extends along the internal wall of the peristome, and to which two smaller lateral projections are added. Four to five thick, hollow, very long spines (usually broken in the material examined), their bases surrounded by the secondary calcification of the distal zooid but without being totally masked; two spines on ovicellate zooids, but the bases of the other two remain within the ovicell.

Autozooids with two small distal avicularia (sometimes one or both may be absent), long, with a semicircular distal edge; foramen occupies half of the rostrum. Avicularia located on both sides of the orifice, supported by the peristome, the distal extreme directed towards the orifice and facing slightly upwards. One or two marginal adventitious avicularia may be present, originating from the areolar pores, placed more proximally and directed towards the centre of the autozooid.

Ovicell formed rapidly at the edges of the colony, immersed in the distal zooid and surrounded by secondary calcification, so that it scarcely projects from the surface of the colony; subcircular frontal area regularly perforated by protuberant circular pores. Proximal edge of the ovicell straight, projecting internally in the zoecial orifice.

Ancestrula not observed.

Measurements

MNHN-299 (holotype). AZL: 0.34¡0.04 (24); AZW: 0.29¡0.045 (24); OL: 0.09¡0.005 (10); OW: 0.11¡0.003 (10); OVL: 0.14¡0.02 (11); OVW: 0.15¡0.015 (11); AAL: 0.06¡0.01 (14); AAW: 0.03 (14).

Remarks

In a study of the specimens of Bryozoa collected by the Travailleur and Talisman surveys, Calvet (1906) described the species Schizotheca talismani from Cape Verde; however, the author himself ( Calvet 1906, p 430) expressed his doubts about the inclusion of the species in the genus Schizotheca because of the structure of the ovicell, and also indicated that he was unable to study the form of the orifice in detail as he only had one specimen available.

We have been able to study four samples labelled as Schizotheca talismani deposited in the Muséum National d’Histoire Naturelle and in the Musée Océanographique de Monaco; of these, samples MNHN-299 and MNHN-1038 correspond to the specimen originally cited by Calvet (1906), therefore both should be considered as the holotype of the species. The other two samples, also belonging to the Calvet Collection and originating from Cape Verde, also correspond perfectly to the original description of the species, although they do not appear to have been cited in any publication. Examination of this material has allowed us to confirm the presence of a large lyrula that occupies almost all of the proximal edge of the orifice, and which has a straight distal edge, terminating in two laterally orientated, pointed corners, opposite two small condyles, a characteristic not noted by Calvet (1906). This detail, along with the structure of the ovicell, well-described and represented in the original study ( Calvet 1906), the presence of conspicuous marginal areolae, development of peristome and spines, existence of adventitious avicularia, as well as basal pore-chambers, allows us to place this species in the genus Parasmittina .

More than 70 species ascribed to the genus Parasmittina have been described from throughout the world (see e.g. Osburn 1952; Soule and Soule 1973, 2002; Hayward 1988; Ryland and Hayward 1992; Hayward and Parker 1994). The regions with the greatest diversity of species of the genus are the SW Pacific (more than 20 species), E Pacific (15 species), Hawaii (14 species), and SE Africa (14 species). However, it is not clear if all these species can be considered valid or if they represent simple morphological variations of the same basic pattern. Moreover, there have been frequent misunderstandings, mistaken citations and unjustified synonyms, which makes necessary detailed studies to enable redefinition of the species; such studies have recently been initiated by some authors, although they will probably still be insufficient.

The original material of P. talismani shows similarities to Parasmittina fraseri Osburn, 1952 , a species ranging in the Pacific between California and the Galapagos Islands ( Osburn 1952), and which has also been reported as a fossil from the Pleistocene in Panama and Costa Rica, and from the Pliocene on the Caribbean coast of Panama ( Cheetham et al. 1999). Both species have a similar orifice, deeply immersed and difficult to observe, with a wide straight lyrula with pointed ends, a large number of spines, reduced to two in ovicellate zooids, peristome with two points in the proximal border, enclosing a rounded secondary sinus; small adventitious avicularia frequently situated at the sides of the zoecial orifice.

However, the original description of Osburn (1952) is somewhat broad, and the figure is not very representative. Parasmittina fraseri has also been cited by Soule and Soule (2002), who have used one of the paratypes of the species (# 4) for their description (Dr H. W. Chaney, personal communication, March 2006). However, examination of new photographs of the specimen ( Figure 2B ) sent to us by Dr Chaney ( SBMNH) revealed ogival avicularia, always located on both sides of the orifice, that are larger than originally reported by Osburn (1952). The paratype is very similar to the material collected from the Dominican Republic and Panama, reported as Parasmittina n. sp. 3 on the website http:// eusmilia-geology.uiowa.edu/database/bryozoa/systemat/parasm.htm. On the same website, there is also a reference to P. fraseri , a species of which 11 specimens have been collected in the Gulf of Panama. Miss J. A. Sanner (personal communication, March 2006) sent us more photographs ( Figure 2C ) and unpublished data on this material (unpublished material belonging to Dr A. Cheetham and Dr J. Jackson), that appears to fit well to the original description of the species.

Finally, there is another specimen in the SBMNH collection, labelled as P. fraseri by J. Soule, with the same location and date as paratype # 4 of the species, which, however, corresponds to Parasmittina regularis Soule and Soule, 2002 ( Figure 2D ). Since P. regularis is currently recorded only from its type locality (north of San Francisco) there is a major discrepancy in the label data (from the Isle Raza).

In summary, it appears that the identity of P. fraseri is not sufficiently established and that other undescribed species may be involved. All of the material reported under this name, as well as other similar material, should be examined to establish definitively the characteristics of the species, possible margins of morphological variation, and its distribution, before being able to establish its relation to P. talismani ; however, this type of study is outside the aims of the present study.

Nevertheless, the original material of P. talismani appears to show certain important differences from the species of Osburn (1952): in the Cape Verde material, the peristome is proximally very well-developed, with two long proximal projections that outline a deep rounded median groove that extends along the inner wall of the peristome, and to which two smaller lateral projections are frequently added; distally, the peristome does not appear to be developed on the ovicell, as in P. fraseri , but terminates at the level of the two oral spines. Finally, the avicularia are small, long and distally semicircular, whereas, according to the original description and the holotype of the species ( Figure 2A ), the avicularia in P. fraseri are rounded or elliptical.

Figures

Figure 1. Parasmittina talismani. (A) View of the colony (MNHN-299, holotype); (B) view in perspective, showing the development of the peristome and adventitious avicularia (MNHN-299, holotype); (C) an ovicellate zooid (MNHN- 1037); (D) primary orifice and adventitious avicularia (MNHN-1037); (E) primary orifice and adventitious avicularium (MNHN-299, holotype); (F) two broken zooids showing the lyrula, the adventitious avicularia and the remaining basis of spines under the ovicells (MNHN-1037); (G) growing edge of the colony (MNHN-299, holotype).

Figure 2. (A) Parasmittina fraseri, holotype; (B) Parasmittina sp. (paratype #4 of P. fraseri); (C) P. fraseri; (D) Parasmittina regularis (labelled as P. fraseri). Photographs: (A, B, D) H. Chaney; (C) J. A. Sanner. Scale bars: 0.20 mm (A); 1.00 mm (B); 0.10 mm (C); 0.50 mm (D).

Figure 5. (A–C) Schizotheca buski sp. nov.: (A) group of ovicellate zooids with lanceolate adventitious avicularia (NHM-1899.7.1.5063, paratype); (B) a vicarious avicularium and a kenozooid with a porous plate (left) (NHM- 1899.7.1.5199, holotype); (C) primary orifice (NHM-1899.7.1.5199, holotype). (D–F) Schizotheca tuberigera: (D) group of autozooids, some ovicellate, with adventitious avicularia and a vicarious avicularium (MNHN-14121); (E) group of kenozooids with adventitious avicularia (MNHN-13831); (F) primary orifice (MNHN-14061).