Watersipora Neviani, 1896

Vieira, Leandro M., Jones, Mary Spencer & Taylor, Paul D., 2014, The identity of the invasive fouling bryozoan Watersipora subtorquata (d’Orbigny) and some other congeneric species, Zootaxa 3857 (2), pp. 151-182 : 154

Genus Watersipora Neviani, 1896

Watersipora Neviani, 1896: 120 ; Osburn 1952: 471; Gordon 1989: 40.

Dakaria Jullien in Jullien & Calvet, 1903: 90; Harmer 1926: 1921 (part).

Pachycleithonia Canu & Bassler, 1930: 25 .

Type species. Lepralia cucullata Busk, 1854 , by original designation.

Diagnosis. Colony encrusting, multiserial, uni- to multilamellar, or erect, foliaceous and bilamellar. Colony coloured reddish to black in life owing to pigmented epitheca. Autozooids subrectangular to hexagonal, separated by raised walls. Cryptocystidean frontal shield with numerous rounded pseudopores; latero-oral intrazooidal septula sometimes present proximolateral to orifice; intrazooidal septula sometimes present at proximal corners of frontal shield. Orifice subcircular to oval; poster sometimes with well-defined proximal sinus; condyles present. Operculum reddish-brown to black in colour, often with central band demarcated by sclerites; lucidae often present. Spines absent. Avicularia absent. Ooecia absent; embryos brooded internally in maternal zooid. Multiporous mural pore plates in distolateral and transverse distal walls. Ancestrula schizoporelloid, single, smaller than autozooids, often obscured in later astogeny.

Remarks. Watersipora was introduced monotypically for “ Smittia cucullata Busk, 1854 ” (= Lepralia cucullata Busk, 1854 ) by Neviani (1896) who stated that his fossil specimens were morphologically distinct from Lepralia cucullata . As a consequence, Harmer (1957) suggested using Dakaria Jullien in Jullien & Calvet, 1903 (type species: Dakaria chevreuxi Jullien in Jullien & Calvet, 1903, now Watersipora subtorquata ; see below) rather than Watersipora for Busk’s species. Despite Neviani’s misidentification of his fossil specimens as Smittia (Watersipora) cucullata ( Neviani 1896, p. 120; Gordon 1989, p. 40), Lepralia cucullata sensu Busk, 1854 is best used as the type species of Watersipora for the purpose of stability (see ICZN 1999, Article 70.3).

Pachycleithonia Canu & Bassler, 1930 was introduced monotypically for Pachycleithonia nigra Canu & Bassler, 1930 , from the Galapagos. The genus has been characterized as having ovicells ( Cook 1985), but the ovicellate specimens are distinct from Canu & Bassler’s P. nigra , and Tilbrook (2006) subsequently reassigned them to Nigropercula Tilbrook, 2006. Osburn (1952) synonymised Pachycleithonia with Watersipora , but included Pachycleithonia nigra under the name Watersipora cucullata . We have examined the type material of Pachycleithonia nigra (USNM 8495; Fig. 11 ) and additional material from the Galapagos (NHMUK 1975.5.12.1); this species resembles W. cucullata in colony shape and in having a thick-rimmed orifice and triangular condyles. However, whereas Pachycleithonia nigra has a sinusoid orifice with a convex proximal edge, W. cucullata has a straight or slightly concave proximal edge, as found in the majority of species assigned to Watersipora , and paired intrazooidal (frontal) septula, which are lacking in Pachycleithonia nigra . These two characters in Pachycleithonia nigra also occur, however, in other Watersipora species , e.g. Watersipora subtorquata , which lacks paired intrazooidal septula, and Watersipora arcuata Banta, 1969a , which has an orifice with a convex proximal edge. Following Soule (1961), we recognize the combination Watersipora nigra ( Canu & Bassler, 1930) .

Two other genera have been assigned to the family Watersiporidae . Veleroa Osburn, 1952 is distinct in having numerous communication pores covering the surface of the lateral and distal walls (see Osburn 1952: pl. 57, fig. 7), and Uscia Banta, 1969b has dimorphic ovicellate zooids (see Banta 1969b, figs 2–4).

Figures

FIGURES 6–11. 6–9, Watersipora cucullata (Busk, 1854), NHMUK 1854.11.15.189, lectotype, Aegean Sea. 6, specimen with two autozooids; 7, close-up of an orifice; 8, close-up of the lateral edge of the orifice, showing the condyle and the latero-oral intrazooidal septulum; 9, close-up of the frontal shield. 10, Watersipora atrofusca (Busk, 1856), NHMUK 1892.9.6.4pt, lectotype, Mazatlan, Mexico; autozooidal arrangement. 11, Watersipora nigra (Canu & Bassler, 1930), USNM 8495, holotype, Galapagos; autozooidal arrangement.