Interstitial organisms are organisms that live between the grains in sediments. Such organisms include bacteria, protists, algae, fungi and small animals. Whilst interstitial ecosystems are not as spectacular as the rain-forests or coral reefs, they are vast, covering not just the soils of the continents, but the sediments that cover the floors of the oceans. This vast space supports an equally vast number of tiny organisms, including several phyla of animals with no known relatives in other environments. Molluscs are an important part of interstitial marine environments, and Gastropods from marine sediments are now thought by some scientists to be the most diverse and abundant group of animals on Earth with many more species than there are of Insects, and possibly a greater total biomass.
In a paper published in the journal Zootaxa on 13 June 2012, Daniel Geiger of the Invertebrate Zoology Department at the Santa Barbara Museum of Natural History and Bruce Marshall of the Museum of New Zealand Te Papa Tongarewa describe 13 new species of Gastropod from the waters around New Zealand.
Scissurella regalis. From the Three King Rise, a submarine extension of the Auckland Peninsula. Scale bar is 1 mm. Geiger & Marshall (2012).
Sinezona enigmatica. From Whangarei Harbour. Inset is the protoconch, the earliest growth stage in a Gastropod shell, since marine Gastropods often have a planktonic larval stage this can be quite different from the rest of the shell, making it useful taxonomically. Scale bar is 1 mm. Inset scale bar is 100 μm. Geiger & Marshall (2012).
Sinezona mechanica. From Ocean Bay on Chatham Island. Scale bar is 1 mm. Geiger & Marshall (2012).
The radula (tongue) of Sinezona mechanica. The radulae of Gastropods are covered in chitinous teeth, which are used to scrape up food. The pattern of these teeth is unique to each species, making this an important feature taxonomically. (A) Entire radula. Scale bar = 100 μm. (B) Full width of radula. Scale bar = 20 μm. (C) Central field enlarged. Scale bar = 10 μm. (D) Lateral tooth 4 (arrow). Scale bar = 10 μm. (E) Marginal teeth. Scale bar = 10 μm. Geiger & Marshall (2012).
Sinezona platyspira. From West Norfolk Ridge, West of Cape Reinga. Scale bar is 1 mm. Geiger & Marshall (2012).
Sinezona wanganellica. From Wanganella Bank on the West Norfolk Ridge, about 900 km to the northwest of Auckland. Protoconch inset. Scale bar is 0.5 mm. Inset scale bar is 100 μm. Geiger & Marshall (2012).
Satondella azonata. From Wanganella Bank on the West Norfolk Ridge, about 900 km to the northwest of Auckland. Protoconch inset. Scale bar is 0.5 mm. Inset scale bar is 100 μm. Geiger & Marshall (2012).
Satondella bicristata. From a seamount 130 km south of L'Esperance Rock in the Kermadoc Islands. Scale bar is 0.5 mm. Geiger & Marshall (2012).
Anatoma amydra. From north of New Caledonia. Protoconch inset. Scale bar is 1 mm. Inset scale bar is 100 μm. Geiger & Marshall (2012).
Anatoma amydra. (A) Full width of radula with central field. Scale bar = 10 μm. (B) Marginal teeth. Scale bar = 10 μm. (C) Jaw. Scale bar = 100 μm. (D) Operculum (the closable covering for the entrance hole on some Gastropods). Scale bar = 1 mm. Geiger & Marshall (2012).
Antoma kopua. From off the coast of Sydney. Scale bar = 1 mm. Geiger & Marshall (2012).
Anatoma megascutula. From east of Rapa in French Polynesia. Protoconch inset. Scale bar is 1 mm. Inset scale bar is 100 μm. Geiger & Marshall (2012).
Anatoma tangaroa. From northwest of the Three Kings Islands. Protoconch inset. Scale bar is 1 mm. Inset scale bar is 100 μm. Geiger & Marshall (2012).
Larochea spirata. From the West Norfolk Ridge, west of Cape Reinga. Scale bars shell A–B = 1 mm. Scale bars shell C = 0.5 mm. Geiger & Marshall (2012).
Larocheopsis macrostoma. From a seamount 130 km south of L'Esperance Rock in the Kermadoc Islands. Protoconch inset. Scale bar is 1 mm. Inset scale bar is 100 μm. Geiger & Marshall (2012).
See also A new species of Scallop from Western Australia and The Snail that eats Crabs.
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