Parasmittina abrolhosensis, 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 : 165-166

Parasmittina abrolhosensis n. sp.

( Figs 3H , 4A–D )

Parasmittina sp. nov. 2: Bastos et al., 2018: table 1.

Material examined. Abrolhos Bank, Bahia State, Brazil: Holotype: MNRJ-Bry1359, Parcel dos Abrolhos, 4 m depth, February 2014, col. R. Moura, G. Amado-Filho & A. Bastos ; Paratype: MNRJ-Bry1347, California Reef, 25 m depth, March 2015, col. F.C. Moraes, R. Moura, G. Amado-Filho & A . Bastos ; MNRJ-Bry1380, Parcel dos Abrolhos, 4 m depth, February 2014, col. R. Moura, G. Amado-Filho & A. Bastos.

Etymology. Alluding to the type locality (Abrolhos Bank).

Diagnosis. Autozooids rectangular to polygonal with a granular frontal wall, imperforate except for small marginal areolar pores; orifice circular with a peristome developed latero-proximally, 3 or 4 oral spines, U-shaped pseudosinus, a pair of condyles, large, hooked and downwardly curved, and a tall and narrow anvil-shaped lyrula. Three different kinds of avicularia: a single or a pair of elongate avicularia with rostrum elongate and serrated, ending in a rounded tip; small avicularia located singly and randomly on the frontal wall or near the orifice; an infrequent giant, spatulate avicularium located near the orifice. Ovicell globose, large, with ooecial surface perforated by small and circular pores.

Description. Encrusting colonies, uni to multilamellar. Autozooids rectangular to polygonal (312–396–471 µm long x 280–308–360 µm wide), forming a circular patch of zooids around the ancestrula. Frontal shield granular, imperforate except for 14–18 large areolar pores ( Figs 3H , 4A, C, D ). Orifice circular (93–106–113 µm long (including pseudosinus) x 75 –84–99 µm wide) with peristome developed mainly latero-proximally, forming a U-shaped pseudosinus; a pair of large, hooked condyles, curved downwardly; lyrula tall, narrow, anvil-shaped; oral spines distal to the orifice numbering 3–4 ( Fig. 4A, C ). Frontal avicularia diverse: (1) single or a pair of elongate avicularia (121–142–178 µm long) with rostrum slightly elevated on the surface, slightly serrated and curved, ending in a rounded tip, located laterally to orifice and directed proximally, crossbar complete (usually broken) ( Fig. 4A, B ); (2) a similar-shaped avicularium that is smaller (79–90–106 µm long), randomly directed and located on the frontal wall or near the orifice ( Fig. 3H ); (3) occasional giant, spatulate avicularia with smooth rostrum, located lateral to the orifice and directed proximally ( Fig. 4C ). Ovicell globose, wider than long (170–183–204 µm long x 219–236–253 µm wide), large relative to zooid size, extending onto the distal zooid and hiding the distal part of the maternal zooid orifice; ooecial surface perforated by small and circular pores ( Fig. 4D ).

Geographic distribution. Abrolhos Bank, Bahia State, Brazil ( Bastos et al. 2018; present study).

Remarks. Parasmittina spathulata ( Smitt, 1873) has an elongate avicularium very similar to P. abrolhosensis n. sp. but not serrated, and also has short condyles, a medium-sized truncate lyrula, undeveloped peristome and two to four oral spines.

Parasmittina serrula Soule & Soule, 1973 , recorded from Hawaii, Vanuatu, Belize and Jamaica, shares with P. abrolhosensis n. sp. lateral avicularia that are elongate and serrated, 3–4 distal oral spines, and an orifice with a narrow lyrula and large condyles; however, P. serrula has a circular orifice with denticulated condyles (six denticles visible: see Tilbrook 2006), a very large spatulate avicularium with serrated edges and another small avicularium, a rostrum that is acutely triangular, finely denticulate and directed proximally.

Similarly, P. serruloides Harmelin et al., 2009 has an elongated and serrated lateral avicularium, but it also has condyles with coarsely denticulate tips (2–5 teeth), lyrula medium-sized, and lacks the spatulate and larger avicularium.

Another species with elongate, slim and lateral avicularia is P. areolata ( Canu & Bassler, 1927) described from Hawaii, Belize and Jamaica ( Soule & Soule 1973; Winston 1984). This species has a variable number of oral spines (up to six) and an orifice with a narrow lyrula and strongly hooked condyles, but differs from P. abrolhosensis n. sp. in having larger zooids (800–840 µm long x 340–420 µm wide), long, thin, almost straight, lateral avicularia (220–300 µm long) and giant avicularia (500 µm long) with a deep concave rostrum and broad spoon-shaped tip. Soule & Soule (1973) described small avicularia (120–160 µm long) located at the top of the distal rim orifice in P. areolata , another feature not observed in the Abrolhos material.

Parasmittina uncinata Soule & Soule, 1973 shares with P. abrolhosensis n. sp. a slim lateral avicularium, but it has 2–3 oral spines, an orifice with a narrow, acute or truncate lyrula, small avicularia distal to the orifice (similar to P. areolata ), and lacks medium-sized suboral or frontal avicularia. Parasmittina parviuncinata Soule & Soule, 1973 has slim and elongated lateral avicularia, but the orifice lacks a lyrula, and there are two oral spines and additional small acute marginal 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.

FIGURE 4. Scanning electron micrographs of three bryozoan species. A–D. Parasmittina abrolhosensis n. sp. A. Detail of some autozooids showing the orifice, lyrula, condyles and three or four oral spine bases, and a lateral elongate avicularium. B. Detail of an elongate lateral avicularium with serrated rostrum. C. Detail of an autozooid showing the orifice with anvil, tall lyrula and a pair of condyles, and a large and spatulate avicularium. D. Detail of a fragment showing some fertile autozooids. E, F. Hemismittoidea asymmetrica n. sp. E. Detail of some autozooids showing the orifice with six and seven distal spines, large anvil-shaped lyrula, large and triangular avicularia, and a perforated ooecium. F. Detail of a fertile zooid showing a perforated ooecium and orifice with a pair of spines others, hidden by the ooecium. G, H: Stylopoma variabilis n. sp. G. Detail of a fragment showing autozooids and two elongate, spatulate interzooidal avicularia. H. Detail of the distal region of an autozooid showing the orifice with U-shaped sinus, condyles and small triangular lateral avicularium.