Bryopesanser tilbrooki, Winston, Judith E. & Vieira, Leandro M., 2013

Winston, Judith E. & Vieira, Leandro M., 2013, Systematics of interstitial encrusting bryozoans from southeastern Brazil, Zootaxa 3710 (2), pp. 101-146 : 131-132

Bryopesanser tilbrooki sp. nov.

( Fig. 20 ; Table 18 )

Material examined. Holotype: MZUSP 744 ( Fig. 20 A, C, D), measured specimen #2, BIOTA Stn 211. Paratypes: MZUSP 672, #2 [5 specimens], near BIOTA Stn 205, 15 m; MZUSP 743, Biota Stn 211; MZUSP 745 ( Fig. 20 E, F), measured specimen #3, BIOTA Stn 205; VMNH 70027, BIOTA Stn 211. Additional material: MZUSP 710, BIOTA Stn 211.

Supplementary video. http://cifonauta.cebimar.usp.br/taxon/bryopesanser-tilbrooki/

Etymology. Named in honor of Kevin Tilbrook, in recognition of his contribution to the taxonomy of Bryopesanser species.

Diagnosis. Bryopesanser with multiporous frontal shield, small paired avicularia, 7 oral spines (6 in ovicelled zooids), and almost semicircular orifice with shallow, subquadrate sinus.

Description. Colonies encrusting in a single layer on small mineral or shell grains. Zooids are relatively flat, with a beaded frontal surface texture, regularly penetrated by small, irregular, multiporous pseudopores. Zooids have raised lateral edges, their margins distinct. Distal end of zooid with a flattened peristome whose shape reflects the outline of the orifice within it. Orifice almost semicircular anteriorly, with a shallow subquadrate sinus and sloping condyles with a posteriorly crimped edge. Seven long, angled and jointed hollow spines surround the distal and lateral rim of the peristome and orifice; bases of spines brown in color. Small triangular avicularia with a rounded base and a complete cross-bar occur on some zooids, lateral to the orifice, with the mandible oriented distally. Ooecium semicircular, solidly calcified, with a flattened proximal edge; ovicelled zooids with 6 oral spines. Polypides with 11 translucent white tentacles.

Remarks. The new species resembles Bryopesanser pesanseris (Smitt, 1873) , also reported from the Brazilian coast (Tilbrook 2012), but differs from it in orifice shape and in the presence of a frontal shield with multiporous pseudopores. The specimens from São Paulo reported as Mastigophora pesanseris (MZUSP, unregistered specimen; Marcus collection #38) differ from Bryopesanser tilbrooki n. sp. in the shape of the orifice and sinus, and the more porous frontal wall; these specimens belong to a distinct species.

The multiporous pseudopores found in Bryopesanser tilbrooki were also reported in six other species, Bryopesanser capitaneus Tilbrook, 2006 , Bryopesanser crebicolis Tilbrook, 2012 , Bryopesanser grandicella (Canu & Bassler, 1929) , Bryopesanser gardineri Tilbrook, 2012 , Bryopesanser labiones Tilbrook, 2012 and Bryopesanser tonsillorum Tilbrook, 2012 ). However, Bryopesanser tilbrooki is readily distinguished from other species of the genus in having an orifice with a subquadrate sinus and well-developed condyles.

Distribution. São Paulo state, Brazil.

Figures

FIGURE 20. Bryopesanser tilbrooki sp. nov.: A, colony on sand grain. B, several autozooids in a hollow of a grain. C, three zooids showing long hollow spines at lateral to distal edges of orifice. D, ovicelled zooid, showing smooth imperforate calcification and raised proximal margin. E, an orifice with seven spines; one of the paired avicularia can be seen at right of the orifice. F, another zooid, showing spines and avicularia. Scale bars: A – C, 0.2 mm; D, F, 0.1 mm; E, 0.05 mm.

Tables

TABLE 18. Measurements (in mm) of Bryopesanser tilbrooki sp. nov..

	Lz	Wz	Lo	Wo	Lov	Wov	Lanc	Wanc
N	18	18	18	18	9	9	1	1
Mean	0.375	0.276	0.079	0.088	0.122	0.197	0.306	0.216
SD	0.054	0.021	0.016	0.012	0.008	0.023	n/a	n/a
Min	0.288	0.234	0.054	0.072	0.108	0.162	0.306	0.216
Max	0.450	0.306	0.108	0.108	0.126	0.216	0.306	0.216