Scrupocellaria frondis Kirkpatrick, 1890

Tilbrook, Kevin J. & Vieira, Leandro M., 2012, Scrupocellaria (Bryozoa: Cheilostomata) from the Queensland coast, with the description of three new species, Zootaxa 3528, pp. 29-48 : 37-39

Scrupocellaria frondis Kirkpatrick, 1890

( Figure 6 )

Scrupocellaria frondis Kirkpatrick, 1890: 504 , text-fig. 1; Hastings, 1943: 361, fig. 18A–D; Osburn, 1947: 20. Not Scrupocellaria frondis: Thornely, 1912: 140 .

Material examined. Holotype: NHMUK 1888.4.16.200, Pernambuco, Brazil. Other material examined: MTQ G25165, HI10–041, Wistari Reef, off Heron Island, Great Barrier Reef, 23.45053° S, 151.8843° E, 21 November 2010, 16 m, coll. KJT; MTQ G25999, HI10–040, North Heron Island - Tenements 1, 23.43309° S, 151.8843° E, 21 November 2010, 16 m, coll. KJT.

Description. Autozooids at angle to each other, partially back to back, small, gracile, 0.271–0.380 mm (0.299±0.042) long, 0.128–0.149 mm (0.141±0.008) wide, with smooth, proximal gymnocyst, approximately two thirds area of oval opesia, cryptocyst very narrow and smooth. Scutum originating from midway along inner lateral margin of opesia, rounded or oval, the distal edge often truncated, lobes symmetrical. Five or six orificial spines (6–7 in axial zooids), long, directed frontally, the most proximal of the outer spines, overarching the opesia, with 3–4 processes produced frontally. Lateral avicularia appear to be lacking; frontal avicularia on axial zooids, rarely seen elsewhere, originating proximal to cryptocystal rim, directed laterally, raised on a tubular base, rostrum with a hooked tip, mandible triangular, with a sharp, hooked tip. Ovicells smooth, globular, about 0.125 mm long, with up to ten circular or elongate oval pores. Single small axial vibraculum, other vibracula very small and inconspicuous on frontal view of the colony. Basal vibracular chamber trapezoid, with transverse setal groove; setae as long as one zooid.

Remarks. Scrupocellaria frondis is characterised by its small size, the shape of its scuta, the lack of lateral avicularia, and the proximal outer spines that produce frontally directed processes.

Scrupocellaria frondis was originally described from Fernando de Noronha and Pernambuco, Brazil, and reported for Tortugas and Ascension Island Hastings (1943). In this work she redescribed S. frondis and included a comparison with three other Atlantic species, S. cornigera Pourtalès, 1867 , S. pusilla Smitt, 1872 and S. regularis Osburn, 1940 (as S. cervicornis Smitt ); these are all distiguished from S. frondis in having lateral avicularia. Thornely (1912) reported S. frondis from the Indian Ocean but her specimen does not belong to Kirkpatrick’s species owing to the presence of lateral avicularia and barbed rhizoids (see Hastings 1943).

Distribution. Scrupocellaria frondis is still found at Pernambuco and other nearby localities on the Brazilian coast, where it is common on pelagic algae such as Sargassum spp. ( Figure 6 A, B, D), but it has not previously been recorded from Australia. The species was also reported from Ascension Island ( Hastings 1943), Tortugas Islands and Aruba Islands ( Osburn 1947). Two colonies were found off Heron Island although neither was associated with algae.

S. frondis has also recently been found from Lizard Island, GBR (Tilbrook pers. obs.).

Figures

FIGURE 6. Scrupocellaria frondis Kirkpatrick, 1890. A, B, D, specimens found on algae from Alagoas, NE Brazil. C, E, F, MTQ G 25165. A, frontal surface of bifurcating branch, note the ovicelled zooid to the right of the bifurcation. B, basal surface of branch bifurcation. C, frontal surface of branch bifurcation; note the frontal avicularium on the axial autozooid. D, basal surface of branch bifurcation with a single axial vibraculum. E, frontal surface of branch bifurcation; note the frontal avicularium on the axial autozooid. F, several autozooids, one ovicellate and the others with developing ovicells; note the most proximal outer spines on the two autozooids to the left with the characteristic three or four frontal tines. Scale bars: 100 µm (A – F).