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EVIDENCE FOR CHOANOFLAGELLATE/SPONGE RELATIONSHIP:. morphology of choanocytes molecular data. Proterospongia - a colonial choanoflagellate (a type of protist). http://www.ucmp.berkeley.edu /protista/proterospongia.html. 16S rRNA sequences of various eukaryotes. sponges. animals
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EVIDENCE FOR CHOANOFLAGELLATE/SPONGE RELATIONSHIP: morphology of choanocytes molecular data Proterospongia - a colonial choanoflagellate (a type of protist) http://www.ucmp.berkeley.edu /protista/proterospongia.html
animals (cnidarians & ctenophores) sponges choanoflagellates fungi a more recent 18S rRNA tree Michael S. Atkins, Andrew G. McArthur and Andreas P. Teske1 (2000) Ancyromonadida: A New Phylogenetic Lineage Among the Protozoa Closely Related to the Common Ancestor of Metazoans, Fungi, and Choanoflagellates (Opisthokonta) J. Mol. Evol. 51, 278
Halichondria spp. (Demospongiae) http://www-biol.paisley.ac.uk/biomedia/text/txt_pictures.htm
Bath Sponge (Demospongiae) - close-up http://www-biol.paisley.ac.uk/biomedia/text/txt_pictures.htm
Hexactinellid (glass) sponge Euplectella (Venus' flower basket) http://www-biol.paisley.ac.uk/biomedia/text/txt_pictures.htm
Leucosolenia, a calcareous sponge (Calcarea) http://www-biol.paisley.ac.uk/biomedia/text/txt_pictures.htm
SPONGE SUMMARY no mouth cells embedded in extracellular matrix of collagen - an excellent unifying feature ("synapomorphy") of the animals most filter feed via incurrent (ostia, microscopic pores) and excurrent (oscula, macroscopic pores) siphons no body symmetry, one (2?) germ layer hermaphrodites (usually sequential)or separate sexes can reproduce asexually by fragmentation or gemmules (propagules); substantial capacity for regeneration have specialized non-feeding larvae (amphiblastulae & coeloblastulae) pre-Cambrian fossil record key morphological features include collar cells, spicules, archaeocytes
ostia (microscopic) oid oid oid http://www.cognoscere.hpg.ig.com.br/porifera.htm
Sponge gemmules http://www-biol.paisley.ac.uk/biomedia/text/txt_pictures.htm
SPONGE LARVAE amphiblastula coeloblastula From: J.N.A. Hooper & Wiedenmayer, F. (1994): Zoological Catalogue of Australia,12, Porifera, p. 447. with additions from the 'Sponguide'.
(="collar cell") http://www.ucmp.berkeley.edu /porifera/pororg.html
Sponge Spicules Hexactinellidae Demospongiae Calcarea http://www-biol.paisley.ac.uk/biomedia/text/txt_pictures.htm
Chia-Wei Li, Jun-Yuan Chen, and Tzu-En Hua. Precambrian Sponges with Cellular Structures Science February 6 1998, 279: 879-882. (A) A possible longitudinal section of a tubular phosphatized sponge, showing the randomly dispersed monaxonal spicules (s) in the mesohyl (m). Two spicules firmly associated with spicule-producing cells, the sclerocytes, are encircled and enlarged in (E). Scale bar, 100 µm. (E) Archaeocytes (a) in the mesohyl (m). Scale bar, 30 µm.
Rhabdocalyptus dawsoni (the "boot sponge," a hexactinellid) http://www.porifera.org/a/cipixrhy.html S. P. Leys, G. O. Mackie and R. W. Meech (1999) Impulse Conduction in a Sponge J. Exp. Biol.202, 1139–1150
Hermit Crab Sponges Paguristes hummi Paguristes impressus http://www.public.coe.edu/departments/Biology/hermit.html