Rhynchozoon papuliferum, Souto, Javier, Kaufmann, Manfred J. & Canning-Clode, João, 2015

Souto, Javier, Kaufmann, Manfred J. & Canning-Clode, João, 2015, New species and new records of bryozoans from shallow waters of Madeira Island, Zootaxa 3925 (4), pp. 581-593 : 590-592

Rhynchozoon papuliferum sp. nov.

( Figs 28–34 , Table 2 )

Rhynchozoon bispinosa var. Waters 1899: 14.

Material examined. Holotype: MMF 44295, 32º38’03.34’’ N; 16º56’04.05’’ W, 11 m, August 2013, on rock samples. Other material: MM-5307, Rynchozoon bispinosa var. Madeira, with papillae, on Pinna Shell, Waters coll.

Etymology. Latin papula, pimple, and – fer, suffix meaning bear or carry, alluding to Waters’ (1889) description of the frontal avicularia as ‘papilliform.’

Description. Colony encrusting, able to bud zooids frontally. Autozooids with vitreous, nodular frontal shield bordered by 1 or, in some parts of zooids, 2 series of many conspicuous rounded marginal pores. Zooidal boundaries unclear in later ontogeny. Numerous uniporous septula in vertical lateral walls. Primary orifice orbicular, as wide as long; distal and lateral border with small denticulations, these more developed on distal margin, shorter proximally. Proximal rim of orifice with large U-shaped sinus occupying almost 2/3 of its width, slightly accentuated by smooth condyles. Deep asymmetrical peristome developing through ontogeny, not obscuring primary orifice. Oral spines absent. Median suboral, triangular avicularium present in most zooids, laterally directed, distally hooked, its proximal part projecting as a small uncinate process defining a lateral pseudosinus. Frontal avicularia very abundant, with triangular rostrum, cystid immersed in thickened frontal shield of ephebic zooids such that rostrum is at same level as shield surface; proximal part of avicularium triangular, shorter than rostrum. Ooecium globular, frontally flat, acleithral; endoecium completely calcified, ectoecium frontally uncalcified, with two calcified laminae prolonged proximally and joined centrally across labellum. Ooecium covered by secondary calcification in later ontogeny, with only frontal uncalcified ectoecium and proximal border remaining visible. Ancestrula unknown.

Remarks. The new species from Madeira exhibits some similarity to R. bispinosum ( Johnston, 1847) which, however, has two spines, a smaller number of marginal pores (always fewer than 10), and one sinus less developed. Additionally, in R. papuliferum sp. nov., frontal avicularia are very common, with a different morphology, notably a triangular proximal area, compared to R. bispinosum .

Two other species of this genus, indicating a Macaronesian influence, were recently described from the south of Portugal— Rhynchozoon celestinoi Souto, Reverter-Gil & Fernández-Pulpeiro, 2010 and Rhynchozoon rosae Souto, Reverter-Gil & Fernández-Pulpeiro, 2010 —but both have several different characters. Whereas R. celestinoi has an elliptical orifice with a deep, quadrate sinus, R. rosae , with small colonies, has four oral spines and the peristome has a large suboral tubercle and encloses the orifice.

SD, standard deviation; N, number of measurements.

Waters (1899) noted that his Madeiran specimens differed from R. bispinosum in several respects, recording them as ‘ Rynchozoon bispinosa var.’ but not formally naming the variety. According to his account, these specimens were characterized by the presence of “very numerous small, papilliform avicularia scattered over the surface,” with a slit-like opening under the mandible smaller than the mandible. We have examined the original specimens from Waters’ collection kept at the Manchester Museum (MM-5306, MM-5307) and can confirm that those labelled as ‘ Rynchozoon bispinosum var.’ are conspecific with our specimens.

Figures

FIGURES 28 – 34. Rhynchozoon papuliferum, holotype: 28, general aspect of colony surface, with ooecia in different stages of development; 29, 30, autozooids with suboral and frontal avicularia; 31, uniporous mural septula; 32, ooecia; 33, 34, orifices.

Tables

TABLE 2. Measurements (in mm) of Rhynchozoon papuliferum sp. nov.

	Mean	SD	Minimum	Maximum	N
Autozooid length	0.403	0.2386	0.089	0.657	18
Autozooid width	0.245	0.1164	0.093	0.392	18
Orifice length	0.112	0.0063	0.102	0,117	10
Orifice width	0.104	0.0031	0.100	0.109	10
Suboral avicularium length	0.112	0.0067	0.107	0.122	6
Suboral avicularium width	0.053	0.0091	0.045	0.063	6
Frontal avicularium length	0.157	0.0237	0.109	0.195	21
Frontal avicularium width	0.083	0.0066	0.071	0.097	21
Uncalcified ectooecium area length	0.088	0.0084	0.073	0.100	9
Uncalcified ectooecium area width	0.120	0.0108	0.104	0.141	9