Schizotheca fissa ( Busk, 1856 )

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 : 1935-1937

Schizotheca fissa ( Busk, 1856)

( Figure 3 )

Lepralia fissa Busk 1856, p 308 .

Schizotheca fissa (Busk) : Zabala 1986, p 534, Figure 189; Zabala and Maluquer 1988, p 150, Figure 392; Reverter-Gil and Fernández-Pulpeiro 1998, p 48, Plate 2, Figure C; Hayward and Ryland 1999, p 382, Figures 180D, 181.

Not Schizotheca fissa (Busk) : Calvet 1906, p 429 (part: D. 10 Talisman, 1883 ).

Not Schizotheca fissa (Busk) : Canu and Bassler 1925, p 47 (part: st. no. 29).

Not Schizotheca fissa (Busk) : d’Hondt 1978, p 449 (part or whole).

Not Schizotheca fissa (Busk) : Cook 1968, p 204.

Material examined

Lectotype (designated here): NHM-1899.7.1.2470: Busk Coll. Guernsey.

Other material. MNHN-2340: Travailleur 1881, D. 24 (2 eme sér.). 55–77 m. Bonifacio. MNHN-2693: Hastings. MNHN-2697: Etretat. MNHN-6324: (with more species). Vanneau, st. 44, 145 m. Atlantic Morocco. MNHN-7927: Meteor, 29. Manche. MNHN- 7935: (with more species). Meteor, 29. Manche. MNHN-8518: Jean-Charcot, st. 27. 210 m. MNHN-17134: Président Théodore Teissier, no locality. MNHN-17135: Président Théodore Teissier, no locality. MNHN-17136: Président Théodore Teissier, no locality. NHM- 1881.4.29.16: Naples. 35 m. NHM-1897.5.1.800: Hastings. NHM-1899.5.1.1164: (with more species). Guernsey. NHM-1899.5.1.1165: Adriatic. NHM-1899.5.1.1167: Guernsey. NHM-1899.5.1.1168: no locality. NHM-1911.10.1.824: Isle of Skye. NHM- 1911.10.1.825: off Antrim Coast. NHM-1911.10.1.826: (with more species). Guernsey. NHM-1911.10.1.827: (with more species). Bertraghboy Bay , Ireland. NHM- 1934.10.20.122: Hastings. NHM-1936.12.30.383: Liverpool Bay . NHM-1963.2.12.133: Salterton. NHM-1963.3.30.174: (with more species), no locality. NHM-1963.3.30.175: Plymouth , 25 fathoms. NHM-1975.1.12.22: Chios , st. 25. NHM-1975.1.12.70: Chios , st. 4. NHM-1975.7.18.30: St. Raphael-Boulouris. NHM-unreg: Weymouth , Britain. NHMunreg: (with more species). Weymouth. MM-5364: (with more species). Naples. MM- 5365: Naples. MM-5366: Capri. MM-5367: Guernsey. MM-5368: The Sound , Plymouth. MM-5369: The Sound , Plymouth. MM-5370: The Sound , Plymouth. MM-10867: Naples. NMI-1913.307.16: Portrush. NMI-2003.70.9: (with more species). Roundstone. NMI-1911.404.66: off Bonett Clew Bay, Coast of Mayo .

Remarks

Schizotheca fissa is characterized by: convex zooids arranged in clear alternating rows, with a few marginal perforations; suborbicular orifice with a concave proximal edge and two small condyles that delimit an apparent U-shaped sinus; a well-developed tubular peristome, with a median proximal U-shaped notch; presence of six large oral spines, reduced to four in ovicellate zooids; and by large vicarious avicularia, whereas the adventitious avicularia are sporadic and associated distally with the ovicells, which have a narrow proximal fissure. The ancestrula of this species ( Figure 3D, E ) has been formally described by Reverter-Gil and Fernández-Pulpeiro (1998), although there was a previous, unpublished description ( López de la Cuadra 1991).

Although this is the type species of the genus, to date no material corresponding to S. fissa has been formally designated as type material; we therefore designate here the sample NHM-1899.7.1.2470, the only extant colony belonging to the Busk Collection, and cited by the author in the original description, as the lectotype of S. fissa .

As it is the type species of the genus, and theoretically the most common, there has been a certain tendency in previous publications to cite other species of the genus under the name S. fissa ; thus for example, among the material reviewed in the present study, we observed that the citations made by Calvet (1906: material from st. 10), Canu and Bassler (1925: material from st. 29), d’Hondt (1978: part or whole) and Cook (1968) do not correspond to S. fissa but to other species of the genus, as discussed further below. Previous reports of S. fissa must be considered carefully. Revision of museum collection material and of the existing literature allows us to state that this species ranges in the Atlantic from the British Isles to Morocco. We consider here that the citation of the species by Cook (1968) from Cape Verde, the southernmost record considered to date, correspond to an undescribed species of the genus Schizotheca (see further below); there are also two colonies from this area in the Jullien Collection deposited in the MNHN, Paris (MNHN- 2694: Talisman 1883 , D. 104), which do not appear to have been cited in any publications, perhaps because they are labelled as Schizotheca fissa ?; this material indeed corresponds to the same undescribed spedies. Waters (1918) also cited S. fissa from Cape Verde, but we have not had a chance to examine the original material, and the brief description ( Waters 1918) may correspond to several species of Schizotheca . Finally, S. fissa is also well known in the Mediterranean, extending at least as far east as Chios.

Figures

Figure 3. Schizotheca fissa. Ría de Ferrol, NW Iberian Peninsula. (A) General view of the colony; (B, C) two primary orifices; (D) ancestrula and early astogenesis; (E) detail of the ancestrula.