October 2004 Unknown |
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THIS MONTH'S WINNERS: Congratulations: Our October unknown was a difficult identification on two accounts. First, you had to recognize it as a freshwater bryozoan – several of our viewers did this. But beyond this, you had to notice that individuals of this species, when extended out of the jelly-like matrix, do not have a distinct collar at the base of the zooid. This distinguishes Pectinatella from Lophopus (good try Akram Mohamed El Sabrouty and Mike Barton) and Cristatella (good try Rachel Wilson). Only two viewers correctly identified the genus, Pectinatella, of our unknown:
Please note: Prize winners are now drawn each month from the total pool of correct answers for that month. Thanks to all of those who submitted an entry to this contest. Good luck this month! |
Lake Bryozoan – Pectinatella sp. Have you ever noticed a brownish, greenish, or highly transparent blob submerged at the edge of a lake or large pond? Most likely, it is a fascinating colonial member of a rather interesting phylum of animals Ė the phylum Bryozoa. Individual bryozoans (zooids) are actually small worms with a circular (or horseshoe-shaped) rim of outstretched feeding tentacles at the head end. The structure is called the lophophore, making bryozoans one of the three main lophophorate phyla (the others are Brachiopoda and Phoronida). The feeding tentacles of the lophophore are covered with cilia, and theyre particularly effective at creating currents to bring small particulate food (such as bacteria) into the mouth of the worm. This species, Pectinatella, grows large colonies with several hundred to thousands of individuals living together in a jelly-matrix blob. Other bryozoans live in the sea, and the worms in a colony are housed in tiny elaborate „houses made of calcium carbonate. There are at least 4000 species of bryozoa, with new species discovered frequently in many parts of the sea. | |