Comprehensive Description

Read full entry

Description

"Osthimosia notialis sp. nov.
Plate Vg, VIa,b

 

Material

 

HOLOTYPE: BMNH 1990.7.31.9., National Antarctic Expedition, Ross Sea

 

PA RATYPES: BMNH 1990.7.31.10., 'Discovery' Stn 42.

 

Other material: 'Discovery' Stns 167, 190, 371, 1872. National Antarctic Expedition, Ross Sea, March 1903, 3.6.1903, 6.12.1903. British Antarctic Survey, Signy Island, Normanna, E. of Outer Is., 21.2.1986

 

Description

 

Colony forming small pisiform growths, 2-4 mm diameter, slender cylinders up to 10 mm long, or small, encrusting domes; most frequently on erect substrata including other bryozoans, cnidarians or sponge spicules. Autozooids with distinct boundaries; with convex, finely nodular frontal wall bordered by few, large, marginal pores. Primary orifice slightly longer than wide, with a deep, U-shaped proximal sinus comprising one-third its total length; condyles thickened and prominent. Peristome high, typically with well-developed lateral lobes, incorporating medio­proximally a single, relatively large, suboral avicularium with oval rostrum, proximally directed. Vicarious avicularia frequent, as long as autozooids; rostrum narrow, parallel-sided proximally, abruptly expanded to a slender spoon shape distally; palate with extensive foramen; crossbar slender, without a columella. Ovicell spherical, prominent, smooth-surfaced, with a broadly triangular area of smooth entooecium exposed frontally.

 

 

 

                  
Measurements(mm)S.D.
Orifice length200.15 0.005
Orifice width 200.13 0.005
 

 

 

Remarks

 

Osthimosia notialis is distinguished from other Antarctic and sub-Antarctic species of Osthimosia by its relatively large, proximally directed, suboral avicularium, its slender vicarious avicularia, and by the ovicell, which has a relatively larger frontal fenestra than in other species. This rather inconspicuous species is perhaps widely distributed in Antarctic waters; the present material is from localities as far apart as South Georgia and the Ross Sea." (Hayward, 1992: 295-7)

Trusted

Creative Commons Attribution Non Commercial 3.0 (CC BY-NC 3.0)

© National Museum of Natural History, Smithsonian Institution

Source: Antarctic Invertebrates Website (NMNH)

Belongs to 0 communities

This taxon hasn't been featured in any communities yet.

Learn more about Communities

Disclaimer

EOL content is automatically assembled from many different content providers. As a result, from time to time you may find pages on EOL that are confusing.

To request an improvement, please leave a comment on the page. Thank you!