Parasmittina distincta, Ramalho & Taylor & Moraes & Moura & Amado-Filho & Bastos, 2018

Ramalho, Laís V., Taylor, Paul D., Moraes, Fernando Coreixas, Moura, Rodrigo, Amado-Filho, Gilberto M. & Bastos, Alex C., 2018, Bryozoan framework composition in the oddly shaped reefs from Abrolhos Bank, Brazil, southwestern Atlantic: taxonomy and ecology, Zootaxa 4483 (1), pp. 155-186 : 164-165

Parasmittina distincta n. sp.

( Fig. 3C–G )

Parasmittina sp. nov. 1: Bastos et al., 2018: table 1.

Material examined. Abrolhos Bank, Bahia State, Brazil: Holotype: MNRJ-Bry1341, Parcel dos Abrolhos, 4 m depth, February 2014, col. R. Moura, G. Amado-Filho & A . Bastos ; Paratype: MNRJ-Bry1382, Parcel dos Abrolhos, 15 m depth, February 2014, col. R. Moura, G. Amado-Filho & A . Bastos ; MNRJ-Bry1383, California Reef, 25 m depth, March 2015, col. F.C. Moraes, R. Moura, G. Amado-Filho & A. Bastos.

Etymology. From the Latin ' distinctus, -a, -um ', meaning 'different’, referring to the different shapes of the avicularia in this species.

Diagnosis. Autozooids quadrangular to rectangular with coarsely tuberculate frontal wall, imperforate, except for marginal areolar pores. Orifice with usually two, but up to four, distal hollow spines, wide anvil-shaped lyrula and a pair of triangular and prominent condyles; single shoe-shaped avicularium usually located laterally to orifice and directed latero-proximally. Other types of avicularia located laterally to orifice: small triangular avicularia on a raised prominence; rare large triangular avicularia directed laterally; and very rare large avicularia, elongate with a triangular rostrum ending in a rounded tip, directed proximally.

Description. Encrusting colonies. Autozooids rectangular to irregularly quadrangular, longer than wide (327– 455–596 µm long x 245–324–465 µm wide), arranged in quincunx ( Fig. 3C, D ). Frontal wall coarsely tuberculate, imperforate except for 16–22 circular to oval areolar pores along the margin and one or two pores located between the orifice and the frontal avicularium ( Fig. 3C, D ). Orifice almost circular (84–103–129 µm long x 93 –104–116 µm wide) with sparsely beaded distal rim and a wide and shallow sinus; peristome low with raised lateral lappets; large anvil-shaped lyrula (33–42–54 µm wide) occupying the proximal part of orifice ( Fig. 3D–G ); condyles located at the proximal-lateral wall ( Fig. 3E ), triangular and prominent; oral spines usually numbering two but as many as four, strong and hollow ( Fig. 3C–F ). Avicularia diverse. Frequently one or, more rarely, a pair of shoeshaped avicularia (87–104–115 µm long) located on frontal wall, proximal-lateral to orifice, directed proximolaterally; crossbar complete ( Fig. 3C–E ). Two other types of triangular avicularia may occur rarely on the same autozooid located beside the orifice: one is directed laterally or slightly proximally, with raised rostrum and complete crossbar (76–182 µm long) ( Fig. 3F ); the other (very rare) is larger and more elongate (225 µm long), directed proximally, with long triangular rostrum ending in a rounded tip, and complete crossbar ( Fig. 3C ; note that in the studied material the unique example of this type of avicularium was broken, showing just the distal part of the rostrum). Ovicell globose, becoming immersed with age, ooecial surface with large rounded pores ( Fig. 3G ).

Geographic distribution. Parcel dos Abrolhos and California Reef, Abrolhos Bank, Bahia State, Brazil ( Bastos et al. 2018; present study).

Remarks. Six Parasmittina species have been recorded in Brazil: P. trispinosa ( Johnston, 1838) , P. betamorphae Winston, 2005 , P. spathulata ( Smitt, 1873) , P. alba Ramalho et al., 2011 , P. simpulata Winston et al., 2014 , and P. loxoides Winston et al., 2014 . Among these Brazilian species, P. simpulata has similar shoe-shaped avicularia to P. distincta n. sp., but also has giant spatulate avicularia, a narrower lyrula, beaded condyles and one or two distal spines; P. alba has one or two oral spines, shoe-shaped avicularia and triangular avicularia with serrated rostra located more frontal than lateral to orifice, a large and spatulate avicularium present on some zooids, and ooecia perforated with pores or fenestra.

Other species recorded in Brazil lack shoe-shaped avicularia and have other distinctive features as follows: P. loxoides has an orifice without a sinus and shorter and narrower lyrula, and spatulate and giant avicularium directed distally; P. betamorphae has only two oral spines, giant, extremely spatulate avicularia, plus smaller triangular avicularia which can occur on the frontal wall; P. spathulata has long and narrow lateral avicularia in addition to large spatulate avicularia; and P. trispinosa has a short and quadrangular lyrula, and avicularia occupying different positions on the frontal wall. Comparing P. distincta n. sp. with congeneric species associated with corals that also have shoe-shaped avicularium: P. marsupialis ( Busk, 1884) has two distal oral spines and a narrow, usually tall lyrula, numerous avicularia on the frontal surface and other types of avicularia (small and short triangular, large oval, and an additional triangular frontal avicularium); P. protecta ( Thornely, 1905) resembles the new Abrolhos species in its avicularia, orifice and lyrula shape but has two oral spines (rarely three), a well-developed peristome forming a long sharp protuberance in the suboral region, the rounded avicularium has an incomplete crossbar, the triangular avicularium has a serrated rostrum, and the ooecium has larger and more irregular pores. Moyano (1983) described P. proximoproducta which can be distinguished in having several small and an elongate triangular avicularia near the orifice and lacking shoe-shaped avicularia.

Figures

FIGURE 3. Scanning electron micrographs of four bryozoan species. A. Metrarabdotos aff. jani, detail of some autozooids showing orifice with small, slit-shaped sinus and lateral, elongate avicularium. B. Metrarabdotos sp., general view of the fragment showing some autozooids with almost circular orifice and a pair of lateral distal avicularium. C–G. Parasmittina distincta n. sp. C. General view of a fragment showing autozooids with two oral spine bases and different kinds of avicularia: shoe-shaped, triangular and elongate. D. General view of a fragment showing autozooids with almost circular orifice, large lyrula, three or four oral spine bases and shoe-shaped avicularium. E. Detail of orifice showing four oral spine bases, large anvil-shaped lyrula and prominent condyles. F. Detail of two autozooids with two and three distal oral spines and short and large triangular lateral avicularium. G. General view of a fragment showing autozooid with two oral distal spines, lyrula and a putative ooecium. H. Parasmittina abrolhosensis n. sp., general view of a fragment showing some autozooids with different kinds of avicularia, orifice circular with three to four oral spine bases and tall and narrow lyrula.