Parasmittina loxoides Winston, Vieira & Woollacott, 2014

Almeida, Ana C. S., Souza, Facelucia B. C., Farias, Jamile, Alves, Orane F. S. & Vieira, Leandro M., 2018, Bryozoa on disarticulated bivalve shells from Todos os Santos Bay, northeastern Brazil, with the description of two new species, Zootaxa 4434 (3), pp. 401-428 : 409

Parasmittina loxoides Winston, Vieira & Woollacott, 2014

( Fig. 5A–F ; Table 6)

Parasmittina loxoides WINSTON, VIEIRA & WOOLLACOTT, 2014 : P. 202, fIg. 40 (CUM SYN.).

Parasmittina loxa : ALMEIDA et al., 2015A: P. 4.

NOT Smittina trispinosa VAR. loxa : MARCUS, 1937B: P. 225, fIgS 23C, 24.

Material examined. UFBA 1619, UFBA 3323–3325, on valve of Plicatula gibbosa . UFBA 1621, UFBA 1622, UFBA 1627, UFBA 1628, UFBA 1652, UFBA 1654, UFBA 1661, UFBA 3326–3353, on valves of Pinctada imbricata .

Redescription. Colony encrusting ( Fig. 5A ), uni- to multilaminar. Autozooids ( Fig. 5B ) subrectangular to polygonal, surrounded by 18–28 large marginal pores. Frontal wall centrally imperforate, rough. Primary orifice ( Fig. 5C ) longer than wide, distal margin smooth, not beaded; 1–2 oral spines; lyrula short, relatively narrow, truncate (non-alate), occupying about one-sixth or less of orifice length; two downward-directed condyles with serrated tips. Secondary orifice low, developed as two lateral flanges . Avicularia of three types. Avicularia type 1 ( Fig. 5D , arrow) small, triangular, varying in orientation, frequently single, occasionally paired, distolateral or proximolateral to peristome, sometimes along autozooid margin on one side. Avicularia type 2 ( Fig. 5D , circle) small, obovate to truncate, frequently single, occasionally paired, marginal, commonly replacing an areolar pore. Avicularia type 3 ( Fig. 5B, E ) large, spatulate, with orientation depending on location, commonly lateral (straight or with rostrum arched up) and distally directed, sometimes oblique to orifice, with subtriangular foramen and calcified palate occupying about half rostrum length, becoming longer with age. Ovicell ( Fig. 5E, F ) prominent, peripherally covered by secondary calcification from surrounding zooids; becoming submersed with increasing calcification; ectooecium perforated by 21–26 small pseudopores that sometimes coalesce with each other.

Remarks. Winston et al. (2014) recently described P. loxoides based on specimens from Rio de Janeiro, and also reassigned to this species specimens from São Paulo previously reported as Parasmittina loxa ( Marcus, 1937b) . The holotype of P. loxa from Santa Helena, a volcanic island in the tropical South Atlantic Ocean, has been destroyed, thus preventing comparison with the Brazilian species ( Winston et al. 2014).

Since P. loxoides was originally described from a single colony fragment mounted on a SEM stub ( Winston et al. 2014), some morphological characters were not evident (i.e. presence and number of oral spines, ornamentation of condyles, frequency and types of avicularia). Since the taxonomy of Parasmittina Osburn, 1952 is mainly based on the morphology of primary orifice (i.e. distal margin, condyles and lyrula), avicularia and ovicell ( Soule & Soule 1973, 2002; Winston et al. 2014), P. loxoides is here redescribed.

The following combination of characters distinguishes P. loxoides from congeners: autozooids subrectangular to polygonal, with large marginal pores; 1 or 2 oral spines; lyrula short, relatively narrow, truncate (non-alate); condyles with serrate tips; three types of avicularia (small, triangular; small, obovate; large, spatulate); ectooecium of ovicell with 21–26 small pseudopores. Also, among the eight species of Parasmittina known from Brazil (Vieira et al. 2018), P. loxoides is unique in having large avicularia (type 3) distally directed.

Distribution. Western Atlantic: Brazil (Bahia, Rio de Janeiro and São Paulo) (Almeida et al. 2015a; Winston et al. 2014).

Figures

FIGURE 5. Parasmittina loxoides WINSTON, VIEIRA & WOOLLACOTT, 2014, UFBA 1621. A. OVERVIEW Of A COLONY. B. GROUP Of AUTOZOOIDS SHOWINg THE LARgE, MARgINAL PORES AND A LARgE AVICULARIUM. C. CLOSE-UP Of A PRIMARY ORIfICE SHOWINg A SINgLE ORAL SPINE BASE, LYRULA AND CONDYLES. D. GROUP Of AUTOZOOIDS SHOWINg TRIANgULAR (ARROW) AND OBOVATE TO TRUNCATE (CIRCLE) AVICULARIA. E. GROUP Of OVICELLED ZOOIDS WITH SEVERAL TYPES Of AVICULARIA. F. CLOSE-UP Of OVICELLED ZOOIDS. SCALE BARS: A, 500 µM; B, D, E, 200 µM; C, 50 µM; F, 100 µM.