Reptadeonella granulosa, 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 : 126-127

Reptadeonella granulosa sp. nov.

( Figs 17 , 25 C; Table 15 )

Material examined. Holotype: MZUSP 739 ( Fig. 17 E–F), measured specimen #2, BIOTA Stn 211. Paratypes: MZUSP 740, measured specimen #1, BIOTA Stn 211; MZUSP 741 ( Fig. 17 A–D), BIOTA Stn 205; MZUSP 695, specimen #26, Itassucê, São Sebastião, São Paulo, Brazil, 7 m; MZUSP 696, #27 [8 colonies], Itassucê, São Sebastião, São Paulo, Brazil, 7 m; VMNH 70024, measured specimen #3, BIOTA Stn 205; VMNH 70025, BIOTA Stn 205. Additional material: MZUSP 697, #28 [several colonies], Itassucê, São Sebastião, São Paulo, Brazil, 7 m.

Supplementary video. http://cifonauta.cebimar.usp.br/taxon/reptadeonella-granulosa/

Etymology. Feminine diminutive form of Latin adjective, granulosus, granular, for the shape of its zooids, like tiny rough-textured seeds.

Diagnosis. Reptadonella with small white colonies, small zooids with round spiramen placed at zooid center, very thick frontal-shield calcification with radiating ridges, and a thick peristome bearing a membranous area in place of an avicularium.

Description. Colonies small, forming bumpy whitish encrusting patches on small substrata, such as sand grains and shell fragments. Zooids about 0.30–0.40 mm long and 0.20–0.26 mm wide. Frontal walls thick and convex, with ridges of calcification radiating from between the marginal pores toward the central round spiramen. The distal end of each is raised into a short thick peristome surrounding the semicircular orifice. The peristome bears a membranous area rather than an avicularium. Polypides with 11–12 translucent white tentacles. Gonozooids with a broader distal region, a transversely elongated orifice, and more pores above the orifice (although these are hard to see because of the convexity of all zooids of this species).

Remarks. Like other members of the interstitial encrusting fauna, colonies of this species are translucent white, very hard to distinguish against a white shell surface. This species may be found on larger shell fragments than some of the other sand fauna species, and colonies may contain several dozen zooids. Reptadeonella granulosa sp. nov. is readily distinguished from other Reptadeonella species reported from Brazil by its small zooid size, robust frontal shield and short thick peristome with a membranous avicularium-like polymorph lacking a mandible.

This species is quite likely what Marcus (1939, p. 152, pl. 11, fig. 19A, B) reported from Paraná state as Adeona tubulifera (Canu & Bassler, 1930) , which is a much larger species from the Galápagos.

Distribution. São Paulo state, Brazil.

Figures

FIGURE 17. Reptadeonella granulosa sp. nov.: A, colony on large shell fragment. B, group of autozooids. C, single autozooid. D, autozooidal orifice. E, autozooids and a gonozooid. F, edge of colony showing orifice of a gonozooid at lower left and an entire gonozooid at upper right; gonozooids have wider orifices and additional pores distal to the orifice. Scale bars: A, 1 mm; B, F, 0.2 mm; C, 0.1 mm; D, 0.05 mm; E, 0.3 mm.

FIGURE 25. A, sample of sand from Stn 205; the small units on the ruler are millimeters. B, live colony of Disporella calcitrapa sp. nov. encrusting the edge of a quartz grain; tentacles are visible. C, live colony of Reptadeonella granulosa sp. nov. D – F, three frames from a digital video of Rosulapelta rosetta sp. nov., showing a lophophore tentacle curving in towards the mouth during feeding. Scale bars: B, 0.2 mm; C, 1 mm; D – F, 0.1 mm.

Tables

TABLE 15. Measurements (in mm) of Reptadeonella granulosa sp. nov..

	Lz	Wz	Lo	Wo	Lgz	Wgz	Log	Wog
N	18	18	18	18	1	1	1	1
Mean	0.398	0.236	0.057	0.086	0.504	0.288	0.072	0.108
SD	0.039	0.026	0.008	0.018	n/a	n/a	n/a	n/a
Min	0.324	0.198	0.045	0.072	0.504	0.288	0.072	0.108
Max	0.468	0.288	0.072	0.126	0.504	0.288	0.072	0.108