Rhamphostomella, Grischenko & Gordon & Taylor & Kuklinski & Denisenko & Spencer-Jones & Ostrovsky, 2022

Grischenko, Andrei V., Gordon, Dennis P., Taylor, Paul D., Kuklinski, Piotr, Denisenko, Nina V., Spencer-Jones, Mary E. & Ostrovsky, Andrew N., 2022, Taxonomy, ecology and zoogeography of the Recent species of Rhamphostomella Lorenz, 1886 and Mixtoscutella n. gen. (Bryozoa, Cheilostomata), Zootaxa 5131 (1), pp. 1-115 : 82

Rhamphostomella ? peristomata Gontar, 1993

( Fig. 26 )

Rhamphostomella peristomata Gontar, 1993a, p. 12 , fig. 5.

Material examined. Holotype: ZIRAS 1 /44568, colony encrusting shell, 26 August 1969, off Cape Levashov , Paramushir Island , northern Kuril Islands, Pacific Ocean, depth 32 m, SCUBA, collector A.N. Golikov.

Remarks. Gontar (1993a) described Rhamphostomella peristomata from Paramushir Island, northern Kuril Islands. She mentioned a finely granulated to “fine-meshed” pattern on the frontal wall; a rounded primary orifice with a medium-sized lyrula on the proximal border; an irregularly oval peristomial secondary orifice; and a small avicularium with rounded mandible “between the primary and secondary orifices close to proximal border of the first one, somewhat to the right or left of the center of this border” (see Gontar 1993a, p. 12, fig. 5). Ovicells were absent in Gontar’s specimen.

SEM examination of the holotype colony ( Fig. 26 ) revealed that this specimen has: 1) a non-cormidial secondary orifice in a low tubular peristome formed entirely by elevation of the frontal wall of the maternal zooid and lacking sutures (both external and internal); 2) a well-developed distal zooidal wall, forming the distal part of peristome with the distal orifical margin separated from the distal zooidal margin by a distance of half to one-quarter orifice length, and 3) 2–5 areolae (often small) along the distal margin of the zooid.

This set of characters is atypical for Rhamphostomella . No other species in the genus has a subterminal orifice, with areolae extending around the distal zooidal margin. Accordingly, R. peristomata is here only tentatively attributed to this genus, pending further data on morphology and genetics.

Figures

FIGURE 26. Rhamphostomella? peristomata Gontar, 1993. ZIRAS 1/44568 (Paramushir Island, Kuril Islands, Pacific Ocean). A. General view of part of holotype colony. B, C. Frontal view of two autozooids, showing orifices with median lyrula, and small avicularium on internal proximolateral surface of one peristome. D. Lateral view of two zooids, showing enlarged distal area of frontal wall with series of marginal areolar pores (arrows) and small peristomial avicularium. E. Distal half of autozooid, showing circular secondary orifice and lyrula. Scale bars: A, 1 mm; D–E, 200 μm.