Collarina spicata, 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 : 119-120

Collarina spicata sp. nov.

( Fig. 13 ; Table 11 )

Material examined. Holotype: MZUSP 727 ( Fig. 13 ), measured specimen #1, BIOTA Stn 211. Paratypes: MZUSP 728, measured specimen #2 [3 colonies], BIOTA Stn 208; VMNH 70018, measured specimen #3, BIOTA Stn 211; VMNH 70019, BIOTA Stn 208.

Etymology. From Latin spicatus, spiked.

Diagnosis. Flattened costae with spike-like tubercles at lateral edges and near centers of costae, small intercostal pores and 4 thick curved oral spines, the proximalmost pair sometimes fused in a bridge over the orifice.

Description. Colony encrusting on shell grains. Zooids oval, frontal shield made up of about 7 pairs of flat costae, fused at zooid midpoint. They are separated from each other by rows of small pores. Raised, pointed hollow tubercles occur at the outer edge and near the center of each costa, giving the frontal shield a spiked appearance. Orifice smooth and semicircular distally, its proximal edge shallowly convex and showing a faintly uneven surface at high magnification. There are 4 thick, hollow orificial spines. Both pairs bend toward each other, the proximal pair very thick and curving toward the center of the orifice, if not broken off, finally fusing into a bridge across the orifice. No avicularia. No ovicells observed in our material.

Remarks. Collarina spicata sp. nov. is characterized by costae with spike-like tubercles with lumen pores and thick oral spines. This species is distinguished from Collarina balzaci (Audouin, 1826) by the absence of avicularia and the number and size of the intercostal pores (see Bishop 1988; Hayward & McKinney 2002).

The zooidal shape of Collarina spicata resembles that described for Floridan Reginella floridana (Smitt, 1873) (see Winston 2005). Cheetham & Sandberg (1964) assigned the Atlantic Cribrilaria figularis var. floridana Smitt, 1873 to Reginella Jullien, 1886 owing to the presence of zooids with fused costae, some lumen pores and a bifid orifice. Reginella has hyperstomial ovicells with pores and a median keel, while no ovicell has been found in Reginella floridana . Arnold & Cook (1997) noted that some species were misassigned to Reginella and require reexamination. Bock & Cook (2001) noted similarities in zooidal morphology of R. floridana and species of Corbulipora MacGillivray, 1895 , although that genus is clearly distinguished by its multiphased colonies and bifenestrate ovicells. The recently described genus Corbuliporina Vieira et al. (2010) from the Brazilian coast also has zooids with fused coastae and lumen pores, but is distinguished by having colonies with two phases (encrusting and erect), porous ovicells and helmet-shaped interzooidal avicularia. Thus, the Atlantic species Cribrilaria figularis var. floridana as well as the new species are here assigned to Collarina (hence, Collarina floridana comb. nov.).

Like most of the interstitial encrusting species discovered so far, Collarina spicata is characterized by its small size, lack of avicularia, and spines and tubular projections that may buffer zooids against abrasion in its often unstable habitat.

Distribution. São Paulo state, Brazil.

Figures

FIGURE 13. Collarina spicata sp. nov.: A, colony on the side of a shell fragment. B, several zooids, showing projecting tubercles. C, zooids at growing edge of colony. D, orifice and oral spines. Scale bars: A, 1 mm; B, C, 0.1 mm; D, 0.05 mm.

Tables

TABLE 11. Measurements (in mm) of Collarina spicata sp. nov..

	Lz	Wz	Lo	Wo
N	18	18	18	18
Mean	0.344	0.245	0.053	0.070
SD	0.040	0.018	0.008	0.007
Min	0.288	0.198	0.036	0.054
Max	0.432	0.270	0.072	0.081