Reteporella antennata, Ramalho & Muricy & Taylor, 2011

Ramalho, Laís V., Muricy, Guilherme & Taylor, Paul D., 2011, Taxonomic revision of some lepraliomorph cheilostome bryozoans (Bryozoa: Lepraliomorpha) from Rio de Janeiro State, Brazil, Journal of Natural History 45 (13 - 14), pp. 767-798 : 787-789

Reteporella antennata sp. nov.

( Figure 9 )

Material examined

Holotype: MNRJ-175. Paratypes: MNRJ-236, MNRJ-237. REVIZEE Station 2 (23 ◦ 47.629 ′ S, 041 ◦ 42.514 ′ W), all collected by D.C. Savi from the naval ship Diadorim, 20 July 2004, using a trap, depth 341 m. Reteporella beaniana: NHM 1963.3.30.248, Lervik , Hardanger Fiord, Norway, Harmer Collection .

Etymology

The name antennata refers to the antenna shape of the distal spines.

Diagnosis

Colony fenestrate, chalice-like; frontal walls smooth, containing few marginal areolar pores; oral spines antenniform, six in number; ovicell with indistinct fissure and short and wide labellum; frontal avicularia monomorphic, oval with rounded mandible, proximally directed; dorsal avicularia of two kinds, one the same as the frontal avicularia, the second a giant avicularium with rounded mandible, attached below the fenestrae or on internal borders.

Description

Colony erect, fenestrate, large (20 mm high by 30 mm diameter), four to five branches originating from a narrow base, bifurcating and anastomosing to form a circular, chalice-shaped net; white in colour ( Figure 9A,B ).

Autozooids longer than wide (635 µm long, range 588–735 µm, by 257 µm wide, range 206–294 µm), convex, narrower distally, arranged in two series alternately on frontal side of branches; frontal wall smooth with a few marginal pores; secondary calcification present ( Figure 9B,C ). Peristome variably developed, hiding the primary orifice; a long fissure partially closed forming the labial pore which is large and round ( Figure 9D ). Six long peristomial spines (three external and three internal), articulated, antenniform; thicker base, narrowing towards the tip; complete in the distal zooids and often broken in other zooids ( Figure 9B,C ). Ovicell almost globose, hyperstomial, imperforate, wider than long, 196 µm long by 235 µm wide (range 216–255 µm), sometimes embedded in autozooidal calcification; labellum short and wide; fissures normally indistinct; secondary calcification present, usually not covering the entire frontal region ( Figure 9D ).

Frontal avicularia small (94 µm long, range 78–118 µm, by 57 µm wide, range 49–69 µm), oval with short mandible rounded at the tip, cross-bar weak; located below zooid midline, directed proximally; one to two avicularia on frontal wall; avicularium chamber sometimes slightly elevated forming projection on frontal wall ( Figure 9B–E ). Dorsal avicularia of two kinds: one similar to frontal avicularium, small, with a mandible rounded at tip ( Figure 9F ); the other larger (245 µm long, range 216–274 µm, by 122 µm wide, range 98–147 µm), very rare, with mandible rounded at the tip, located immediately below fenestrae or between the dorsal and frontal sides near bifurcations.

Habitat

Found on rock and coralline substrates in deep water (341 m).

Geographical distribution

REVIZEE station 2 (23 ◦ 47.629 ′ S, 041 ◦ 42.514 ′ W), Rio de Janeiro State, Brazil .

Remarks

In the presence of antenniform spines and an oval frontal avicularium, this new species is similar to R. flabellata Busk, 1884 . However, R. flabellata has a dichotomously branched colony which is not fenestrate, dorsal avicularia are absent, and branches are formed by one to three series of zooids.

Hitherto, no species of Reteporella has been recorded from Brazil. Hayward (1993, 1995) mentioned nine Reteporella species in the Antarctic region, but all of these have large to giant avicularia and oral spines are absent or less frequent than in the new species. Gordon (1989) described three new species of Reteporella from New Zealand, but most of these are not fenestrate and differ in other characters from the Brazilian species. Hayward and Ryland (1996) described five Reteporella species from North Atlantic waters. These species differ from the new Brazilian species principally in having fewer spines, avicularia lateral or proximal of the orifice, and triangular avicularian mandibles. Gordon and d’Hondt (1997) described five species from New Caledonia which also differ from the new Brazilian species as giant avicularia and oral spines are absent.

Figures

Figure 9. Reteporella antennata sp. nov. (A,B) Views of the cup-shaped colony; (C) distal branch showing autozooidal arrangement, antenna-like spines and labial pore; (D) autozooidal arrangement at bifurcation region; (E) ovicellate autozooids and frontal avicularia. F. Avicularia. Scale bars: A,B: 0.5 cm; C–E: 200 µm; F: 50 µm. MNRJ-175.