Petraliella globulata, Chae & Kil & Seo, 2016

Chae, Hyun Sook, Kil, Hyun Jong & Seo, Ji Eun, 2016, Taxonomic study on bryozoans - new additions to the Korean fauna and new species of Petraliella from Seogwipo waters of Jeju Island, Journal of Species Research 5 (3), pp. 551-565 : 562-563

*** 55. Petraliella globulata n. sp. ǟȓ난ṴḂȐŘ위ÑnjḇNj (신ḡ) ( Fig. 6 )

Material examined. Hangaechang in Munseom Is., 20 Apr. 2012 (B.S. Min). Holotype (NIBRIV0000711261) and Paratype (NIBRIV0000707781) have been deposited in the National Institute of Biological Resources ( NIBR), Incheon, Korea .

Substratum. Worm tubes.

Description. Colony encrusting. Autozooids arranged regularly, rectangular, separated by distinct sutures, longer than wide (807­1086 μm long and 487-671 μm

wide), with curved distal rim at center ( Fig. 6A ). Frontal surface flat, uniformly perforate with small pores with marginal large pores. Lateral walls distinct, prominent with deep pits. Orifice ( Fig. 6B ) rectangular, as wide as long (209­243 μm long and 230-266 μm wide), con­ stricted at distance of one­third from proximal, with one pair of strong condyles concealed. Avicularia lateral to orifice, single or paired, variable in size, but generally paired, triangular, projecting, directed distally; rostrum sharply narrowed from crossbar, curved basally at distal end; crossbar complete (147­203 μm long and 71-84 μm wide). Single frontal avicularia often on proximal corner, when older, smaller. Sometimes frontal avicularium proximal to orifice, directed laterally. Ovicell ( Fig. 6C ) prominent, globular, as wide as long (502­616 μm long and 502­589 μm wide), uniformly perforate with minute pores, raised at marginal rim, placed at top of distal to orifice. Orifice not closed by ovicell. Basal surface ( Fig. 6D ) smooth with small pores centrally or proximally.

Remarks. Petraliella globulata n. sp. is characterized by its subrectangular orifice with straight proximal border, shape and location of the ovicell. Petraliella globulata n. sp. appears to be similar to P. crassocirca Canu and Bassler, 1929 in having setiform oral avicularia direct­ ed distally and the shape of orifice and frontal wall. However, this new species shows the differences from P. crassocirca in the characteristics of the ovicell. The ovicell of P. globulata n. sp. is prominent, globular, as wide as long (502­616 μm long and 502-589 μm wide), uniformly perforate with minute pores, raised at marginal rim, placed at the top of distal to orifice, and does not cover the orifice.

Only one species, P. magna belonging to the genus Petraliella was reported from the coastal waters of Korea by Rho and Kim (1981), Rho and Seo (1984), Seo (1992; 2005), Song and Won (1992) so far. P. globulata n. sp. and P. magna have similarities in the location of oral avicularia lateral to orifice, however show the differences in its shape. The oral avicularia of the new species shows its rostrum sharply narrowed toward crossbar, curved at distal end basally, whereas one of P. magna is smaller and has round rostrum.

Etymology. The scientific name, globulata , is derived from Latin ‘globosus’, refers to the shape of globose ovicell.

Figures

Fig. 6. Petraliella globulata n. sp.A. zooids. B. orifices. C. ovicells. D. basal surface. Scale bars: 100 μm (A­D).