Exochella moyanoi, Ramalho, Laís V. & Calliari, Lauro, 2015

Ramalho, Laís V. & Calliari, Lauro, 2015, Bryozoans from Rio Grande do Sul Continental Shelf, Southern Brazil, Zootaxa 3955 (4), pp. 569-587 : 578-580

Exochella moyanoi sp. nov.

( Fig. 6 A–C)

Exochella longirostris Marcus, 1937: 82 , fig. 43; Marcus, 1941: 22, fig. 16; Marcus, 1949: 1.

Material examined. Parcel do Carpinteiro, Rio Grande do Sul, Brazil: MNRJ-1176, am28 point 1, 32°10.086’S, 51°28.269’W, 28 August 2009; MNRJ-1211, am09 pc 1, 32°17.032’S, 51°48.754’W, 40 meters depth, 28 September 2009; MNRJ-1212, am24 station2, 32° 09.406S, 51° 28.318W, 31 July 2009; MNRJ-1213, am30 station 0 1, 32°14.300’S, 51°46.630’W, 25 meters depth; MNRJ-1214, am12, 32°16.724’S, 51°47.111’W, 25 meters depth; MNRJ-1215, am05, 32°16.894’S, 51°48.454’W, 24 meters depth, 28 March 2007; Hermenegildo, Rio Grande do Sul, Brazil: MNRJ-1216, HS#24, 33°45.326’S, 53°13.991’W, 18 meters depth, June 2011, Coll. FURG.

Description. Colony encrusting, unilamellar with usually regular growth ( Fig. 6 A).

Autozooids disposed in quincunx, rectangular (271–443 (341) µm long x 171–243 (197) µm wide); frontal wall smooth, convex with only areolar horizontally elongate (11–15) ( Fig. 6 A–B). Secondary orifice D-shaped (86–100 (93) µm long x 86 –100 (95) µm wide) with rounded anter and almost right poster, usually with one central mucro; condyles present almost or just the lateral midline of the orifice; three to five thin distal oral spines, usually shared by oecium ( Fig. 6 B–C).

One (usually) or two avicularia (86–129 (105) µm long) on the frontal surface located almost middle length of the zooid, near the margin, laterally directed (outwards), on the right or left side (when two avicularia are present, one on each side); triangular mandible; crossbar complete ( Fig. 6 B–C).

Oecium rounded (157–200 (174) µm long x 186–243 (217) µm wide), immersed on the frontal wall of the next zooid, smooth surface with areolar pores; dependent orifice ( Fig. 6 B–C).

Etymology. The name moyanoi is in honour to Dr. Hugo Moyano who dedicated his life to Bryozoan studies.

Geographic distribution. Rio Grande do Sul States (Parcel do Carpinteiro and Hermenegildo - present study).

Remarks. Jullien (1888) described Exochella longirostris from Cap Horn and following authors recorded this species for the Atlantic Ocean ( Waters 1889; Rogick 1956; Lagaaij 1963). Marcus also recorded some colonies of this species for São Paulo and Paraná States ( Marcus 1937, 1941). However, Hayward (1995) redescribed E. longirostris Jullien, 1888 and mentioned that this species is strictly magellanic (Southern Chile to the Falkland Isles) and Winston et al. (2014) suggested that Marcus’ material (from São Paulo, Marcus 1937) belonged to a distinct species. Despite of E. longirostris being similar to E. moyanoi n. sp., the first one has larger zooids (480– 500 µm long x 300–430 µm wide) with rounded areolar pores, three distal oral spines, avicularia with slender and acuminate rostrum, and oecium coarsely nodular.

Winston et al. (2014) described a new species from the Brazilian coasts (Rio de Janeiro State), Exochella frigidula . This species can be distinguished from E. moyanoi as it has two to four distal spines, larger autozooids (396–522 (456) µm long x 324–486 µm wide), longer avicularia (108–180 (156) µm long) with heavy rims and rostrum on a raised camara. Another similar species is E. tropica Winston & Woollacott, 2009 , but it has larger autozooids (455–516 (494) µm long x 218–309 (261) µm wide), a thick tubercle below the peristome, larger avicularia (127–218 (170 µm long) with rostrum raised at an angle from downsloping zooid margins and oriented slightly distolaterally. So, we believe that E. moyanoi is a new species.

Figures

FIGURE 6. Exochella moyanoi sp. nov. (MNRJ- 1176). A, colony fragment with abundant ovicellate zooids; B, ovicellate zooids; note orifice shape and the median suboral umbo in most zooids, and two avicularia at upper right; C, close-up of ovicellate zooids; two lateral avicularia visible. Scalebars: A, 500 µm; B, 200 µm; C, 100 µm.