Turritigera buski, 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 : 792-796

Turritigera buski sp. nov.

( Figures 11 , 12 )

Material examined

Holotype: MNRJ-182; Paratype: MNRJ-240, REVIZEE Station 9 (24 ◦ 16.353 ′ S, 043 ◦ 23.788 ′ W), collected by D.C. Savi from naval ship Diadorim with a trap, 24 July 2004, depth 600 m. Turritigera stellata: NHM 1887.12.9.520, 1944.1.8.240, Challenger, Station 320, depths 1100 m and 600 m, respectively. NHM 1934.2.16.13, Challenger , Cape Hope , station 142, depth 275 m. Turritigera cribrata : Holotype: NHM 1992.10.19.7, Discovery Expedition station 42, depth 120–204 m. Paratype: NHM 1992.10.19.8, British Antarctic Expedition, station 355, Terra Nova. NHM 1997.8.1.9, Discovery Expedition. NHM 1997.8.1.10, McMurdo Sound, Ross Sea. Turritigera fenestella : Holotype: NHM 1890.4.16.2B, Marion Island (38 ◦ S, 046 ◦ 40 ′ W). Turritigera reticulate : Holotype: NHM 1890.4.16.2A, Marion Island (38 ◦ S, 046 ◦ 40 ′ W) .

Etymology

The name buski is in honour of George Busk who first described species of Turritigera .

Diagnosis

Colony arborescent, white, with two or three series of zooids opening on frontal sides of branches. Autozooids with large sinus, slightly wider than deep; peristome well developed. Ovicell proximal, globose, opening inside peristome. Peristomial avicularia numbering one to five, the most distal being largest; small avicularia, similar to peristomial avicularia, located on frontal and dorsal sides; large avicularia only on dorsal side, spatulate.

Description

Colony arborescent, dichotomously branched, strongly calcified, up to 30 mm high, white in colour ( Figure 11A ).

Autozooids opening on one side of branch (frontal), in series of up to three ( Figure 11B ), elongate, longer than wide, not separated by sutures, delimited by large pores ( Figure 11C ); peristome variably developed, sometimes very elevated, normally covering primary orifice ( Figure 11C ) which has a narrow to moderately wide sinus (38 µm long by 54 µm wide), well delimited ( Figure 11D ). A few small pseudopores scattered on frontal surface ( Figure 11C–F ). In some zooids, a large fissure occurs immediately below the peristome ( Figure 11F ).

Peristomial avicularia numbering one to five, depending on ontogenetic stage; distal avicularium sometimes a little larger than the others, all avicularia turned outwards, sometimes on a process elevated above surface of peristome ( Figure 11C,E,F ). Other small avicularia, similar to peristomial avicularia, scattered across dorsal and frontal branch surface ( Figure 11B , 12A,B ), mandible triangular. Giant avicularia occur on dorsal sides (300 µm long), the sole example observed located at a bifurcation ( Figure 12C,D ); mandible dilated and rounded at tip, turned to the side, facing slightly downwards; cross-bar complete.

Ovicell prominent, located proximally of orifice, surface similar to the zooidal frontal wall, opening inside the peristome; small pores present ( Figure 12E ).

Habitat

Colonies found on rock at 600 m deep, fouled by small colonies of Patinella sp.

Geographical distribution

REVIZEE Station 9 (24 ◦ 16.353 ′ S, 043 ◦ 23.788 ′ W), Rio de Janeiro State, Brazil .

Remarks

Five species of the genus Turritigera have been described previously: T. cribrata Hayward, 1993 , T. spectabilis d’Hondt, 1981 , T. reticulata Cook and Hayward, 1983 , T. fenestella Cook and Hayward, 1983 and T. stellata Busk, 1884 . The four first species are clearly different from T. buski (see d’Hondt 1981a and b; Cook and Hayward 1983; Hayward 1993).

Busk’s species T. stellata , as redescribed by Cook and Hayward (1983) and Hayward (1993) from two different Challenger stations (Stn 320 from Uruguay, and Stn 142 from South Africa), is variable. According to Hayward (1993), the specimen from Uruguay has a more delicate colony, narrower and U-shaped sinus, peristomial avicularia of equal size and a dorsal avicularium that is large and spatulate, whereas the specimen from South Africa has a more robust colony, large and shallow sinus, the distal peristomial avicularium is larger than the others, and large dorsal avicularia are lacking. If it were not for the different shape of the sinus, specimens from the two stations could be assigned to the same species as there may be variation among the types of peristomial avicularia in the same colony and the dorsal avicularia may be rare. However, the shape of the sinus is clearly important taxonomically (see Hayward 1993: 1427), and this feature argues against the specimens from Uruguay and South Africa being conspecific. Turritigera buski sp. nov. is close to putative T. stellata from Uruguay but T. stellata has more (up to seven) peristomial avicularia which are all very similar in size, lacks small triangular avicularia on the dorsal side, has interzooidal avicularia on the frontal shield, and, importantly, a primary orifice with a narrow, U-shaped median sinus (40 µm long by 30 µm wide; Hayward 1993, table 1, fig. 7D).

This is the first record of Turritigera from the Brazilian coast. The lack of previous records may reflect the paucity of studies of bryozoan faunas from deep water where Turritigera is typically found ( d’Hondt 1981a,b; Cook and Hayward 1983; Gordon 1989; Hayward 1995). Almost all species from the southern hemisphere have been recorded in deep (up to 4300 m) and cool (−0.3 to +17 ◦ C) water; hitherto tropical or subtropical species were unknown ( d’Hondt 1981a; Cook and Hayward 1983; Hayward 1993).

Conclusion

This study of lepraliomorph cheilostomes from Rio de Janeiro State describes 10 species, five of which are new: Parasmittina alba , Microporella proxima , Reteporella antennata , Stephanollona robustaspinosa and Turritigera buski . The genera Reteporella and Turritigera are newly recorded from Brazilian waters. Of the species previously recorded from Brazil, Arthropoma cecilii , Celleporina diota and Reteporellina evelinae are new occurrences for Rio de Janeiro State. The diversity of bryozoans known from Brazil and Rio de Janeiro State is increased: before this study, 69 species were recorded from Rio de Janeiro State ( Barbosa 1964; Buge 1979; Ramalho et al. 2005, 2008a,b, 2009); this number now rising to 79 species. It is likely that far more species await discovery in this poorly sampled region.

Arraial do Cabo was found to have the greatest local diversity of lepraliomorph species, containing seven of the 10 species described here. Most of these species were found in small areas, except for S. errata and W. subovoidea , which were more widespread and were collected in four areas: Macaé, Arraial do Cabo, Guanabara Bay and Sepetiba Harbor. Both species were in reproductive condition and were normally found in polluted harbour environments, as they are elsewhere in the world.

Figures

Figure 11. Turritigera buski sp. nov. (frontal view). (A) General frontal view of the colony; (B) frontal view showing autozooids; (C) form and disposition of the autozooids, peristomial avicularia and marginal pores (larger) and small pseudopores spread on the frontal wall; (D) detail of the primary orifice, showing U-shaped sinus; (E) detail of peristome showing form and disposition of avicularia; (F) peristome with one avicularium. Scale bars: A: 3 mm; B: 900 µm; C, F: 100 µm; D, E: 60 µm. MNRJ-182.

Figure 12. Turritigera buski sp. nov. (dorsal view). (A) General view; (B) pseudopores and small avicularia; (C) bifurcation showing a large, spatulate avicularium; (D) detail of large avicularium; (E) ovicell (frontal side). Scale bar: A: 400 µm; B, E: 100 µm; C: 300 µm; D: 60 µm. MNRJ-182.