Porifera References

References

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Álvaro JJ, O Elicki, F Debrenne & D Vizcaïno (2002), Small shelly fossils from the Lower Cambrian Lastours Formation, southern Montagne Noire, France. Geobios 35: 397–409. Archaeocyatha.

Álvaro JJ, O Elicki, G Geyer, AWA Rushton & JH Shergold (2003), Palaeogeographical controls on the Cambrian trilobite immigration and evolutionary patterns reported in the western Gondwana margin. Palaeogeog. Palaeoclimat. Palaeoecol. 195: 5-35. Archaeocyatha.

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Aouacheria A, C Geourjon, N Aghajari, V Navratil, G Deléage, C Lethias, & J-Y Exposito (2006), Insights into early extracellular matrix evolution: Spongin short chain collagen-related proteins are homologous to basement membrane type IV collagens and form a novel family widely distributed in invertebrates. Mol. Biol. Evol. 23: 2288-2302. Demospongiae, Homoscleromorpha.

Barthel D (1995), Tissue composition of sponges from the Weddell Sea, Antarctica: not much meat on the bones. Mar. Ecol. Progr. Ser. 123: 149-153. Demospongiae.

Bavestrello G, U Benatti, B Calcinai, R Cattaneo-Vietti, C Cerrano, A Favre. M Giovine, S Lanza, R Pronzato & M Sara 1998), Body polarity and mineral selectivity in the demosponge Chondrosia reniformis. Biol. Bull. 195: 120-125. Porifera.

Bengtson S (2000), Teasing fossils out of shales with cameras and computers. Pal. Elect. 3: 4, 14 pp. Porifera.

Bergquist PR & M Kelly (2004), Taxonomy of some Halisarcida and Homosclerophorida (Porifera: Demospongiae) from the Indo-Pacific. N.Z. J. Marine & Freshwater Res. 38: 51-66. Homoscleromorpha.

Benton MJ & DAT Harper (1997), Basic Paleontology. Addison Wesley Longman, 342 pp. Archaeocyatha, Demospongiae, Irregulares, Stromatoporoidea.

Blumenberg M (2003), Biomarker aus Kaltwasser- und Tiefsee-Kieselschwämmen: Phylogenie, Chemotaxonomie und Chemische Ökologie der Demospongiae und der Hexactinellida. Unpubl. Ph.D. Diss., Universität Hamburg. 120+ pp. Homoscleromorpha, Tetractinomorpha.

Bond D, PB Wignall & G Racki (2004), Extent and duration of marine anoxia during the Frasnian–Famennian (Late Devonian) mass extinction in Poland, Germany, Austria and France. Geol. Mag. 141: 173-193. Stromatoporoidea.

Botting JP & NJ Butterfield (2005), Reconstructing early sponge relationships by using the Burgess Shale fossil Eiffelia globosa, Walcott. Proc. Nat. Acad. Sci. (USA) 102: 1554–1559. Demospongiae, Hexactinellida, Porifera, Porifera Cladogram.

C. Borchiellini, M. Manuel, E. Alivon, N. Boury-Esnault, J. Vacelet & Y. Le Parco (2001). Sponge paraphyly and the origin of Metazoa. Journal of Evolutionary Biology 14 (1): 171–179. doi:10.1046/j.1420-9101.2001.00244.x. pdf - Porifera - Index page

Bottjer DJ, JW Hagadorn & SQ Dornbos (2000), The Cambrian substrate revolution. GSA Today 9: 2-6. Archaeocyatha.

Boury-Esnault N & AM Solé-Cava (2004), Recent contribution of genetics to the study of sponge systematics and biology. Boll. Mus. Ist. Biol. Univ. Genova, 68: 3-18. Tetractinomorpha.

Boute N, J-Y Exposito, N Boury-Esnault, J Vacelet, N Noro, K Miyazaki, K Yoshizato& R Garrone (1996), Type IV collagen in sponges, the missing link in basement membrane ubiquity. Biol. Cell. 88: 37-44. Demospongiae, Homoscleromorpha, Porifera.

Budd GE (2003), The Cambrian fossil record and the origin of phyla. Integr. Comp. Biol. 43: 157-165. Irregulares.

Cao R-J (1999), Evidence for possible metazoan activity in Neoproterozoic aberrant stromatolites and thrombolite structures. Acta Pal. Sin. 38: ??-??. Irregulares.

Cavalier-Smith T & EE-Y Chao (2003), Phylogeny of Choanozoa, Apusozoa, and other protozoa and early eukaryote megaevolution. J. Mol. Evol. 56: 540-563. Demospongiae, Hexactinellida.

Chombard C, N Boury-Esnault, A Tiller & J Vacelet (1997), Polyphyly of “sclerosponges” (Porifera, Demospongiae) supported by 28S ribosomal sequences. Biol. Bull. 193: 359-367. Archaeocyatha, Stromatoporoidea.

Corsetti FA & AJ Kaufman (2003), Stratigraphic investigations of carbon isotope anomalies and Neoproterozoic ice ages in Death Valley, California. GSA Bull. 115: 916–932. Archaeocyatha.

Croce G, D Viterbo, M Milanesio & H Amenitsch 2006), A mesoporous pattern created by nature in spicules from Thetya aurantium sponge. Biophys. J. 92: 288-292. Demospongiae. 

Daly M, DG Fautin & VA Cappola (2003), Systematics of the Hexacorallia (Cnidaria: Anthozoa). Zool. J. Linn. Soc. 139: 419-437. Stromatoporoidea.

Dana JD (1896), Manual of Geology (4th ed.) Amer. Book Co., 1088 pp., reprinted at Nineteenth Century Science. Hexactinellida.

Degnan BM, SP Leys & C Larroux (2005), Sponge development and antiquity of animal pattern formation. Integr. Comp. Biol., 45: 335–341. Demospongiae.

Diehl-Seifert B, B Kurelec, RK Zahn, A Dorn, B Jeričevic, G Uhlenbruck & WEG Müller (1985), Attachment of sponge cells to collagen substrata: effect of a collagen assembly factor. J. Cell Sci. 79: 271-285. Tetractinomorpha.

Dornbos SQ, DJ Bottjer & J-Y Chen (2005), Paleoecology of benthic metazoans in the Early Cambrian Maotianshan Shale biota and the Middle Cambrian Burgess Shale biota: evidence for the Cambrian substrate revolution. Palaeogeog. Palaeoclimat. Palaeoecol. 220: 47-67. Archaeocyatha, Demospongiae.

Dupraz C, R Pattisina & EP Verrecchia (2006), Translation of energy into morphology: Simulation of stromatolite morphospace using a stochastic model. Sediment. Geol. 185: 185–203. Irregulares.

Eckert C, HC Schröder, D Brandt, S Perovic-Ottstadt & WEG Müller 2006), Histochemical and electron microscopic analysis of spiculogenesis in the demosponge Suberites domuncula. J. Histochem. Cytochem. 54: 1031–1040. Demospongiae.

Eerkes-Medrano DI & SP Leys (2006), Ultrastructure and embryonic development of a syconoid calcareous sponge. Invert. Biol. 125: 177-194. Demospongiae, Homoscleromorpha.

Ereskovsky AV & EL Gonobobleva (2000), New data on embryonic development of Halisarca dujardini Johnston, 1842 (Demospongiae, Halisarcida). Zoosystema 22: 355- 368. Demospongiae, Homoscleromorpha.

Erpenbeck D & RWM van Soest (2006),Status and perspective of sponge chemosystematics.Marine Biotech. 9: 2-19. Homoscleromorpha.

Erpenbeck D & G Wörheide (2007), On the molecular phylogeny of sponges (Porifera). Zootaxa 1668: 107-126. Homoscleromorpha.

Exposito J-Y, C Cluzel, R Garrone & C Lethias (2002), Evolution of Collagens. Anat. Rec. 268: 302-316. Demospongiae, Homoscleromorpha.

[Feng, W-M] 冯 伟民, [Z Chen] 陈 哲, & [W-G Shun] 孙 卫国 (2002), 晚前寒武纪末至早寒武世生物骨髓: 微细结构的分异. Sci. China D 32: 850-856. Irregulares.

García-Bellido Capdevila D (2003), The demosponge Leptomitus cf. L. lineatus, first occurrence from the Middle Cambrian of Spain (Murero Formation, Western Iberian Chain). Geol. Acta 1: 113-119. Demospongiae.

Galloway JJ & J St. Jean (1955), The type of the stromatoporoid species Stromatocerium rugosum Hall. Am. Mus. Nov. No. 1728, 12 pp. Stromatoporoidea.

Gatenby JB (1927), Further notes on the gametogenesis and fertilization of sponges. J. Cell Sci. 282: 173-188. Homoscleromorpha.

Grotzinger JP, WA Watters & AH Knoll (2000), Calcified metazoans in thrombolite-stromatolite reefs of the terminal Proterozoic Nama group, Namibia. Paleobiology, 26: 334-359. Irregulares.

Hagadorn JW (2002), Chengjiang: Early record of the Cambrian explosion, in DJ Bottjer, W Etter, JW Hagadorn & CM Tang (eds.), Exceptional Fossil Preservation: A Unique View on the Evolution of Marine Life. Columbia Univ. Press. Demospongiae, Hexactinellida.

Hagadorn JW, S-H Xiao, PCJ Donoghue, S Bengtson, NJ Gostling, M Pawlowska, EC Raff, RA Raff, FR Turner, Y Chongyu, C-M Zhou, X-L Yuan, MB McFeely, M Stampanoni & KH Nealson 2006), Cellular and subcellular structure of Neoproterozoic animal embryos. Science 314: 291-294. Demospongiae.

Hladil J (2007), The earliest growth stages of Amphipora, in B Hubmann & WE Piller (eds.), Fossil Corals and Sponges. Proceedings of the 9th Int. Symp. Fossil Cnidaria and Porifera. Österr. Akad. Wiss., Schriftenr. Erdwiss. Komm. 17: 51–65. Porifera Cladogram, Stromatoporoidea

Igo H, H Igo & S Adachi (1988), Permian sphinctozoan sponges from the Ichinotani Formation, Hida Massif, central Japan. Trans. Proc. Pal. Soc. Japan, N.S., 150: 453-464. Stromatoporoidea.

Jiang G-Q, MJ Kennedy & N Christie-Blick (2003), Stable isotopic evidence for methane seeps in Neoproterozoic postglacial cap carbonates. Nature 426: 822-826. Stromatoporoidea.

Kouchinsky A, S Bengtson, V Pavlov, B Runnegar, A Val'kov & E Young (2005), Pre-Tommotian age of the lower Pestrotsvet Formation in the Selinde section on the Siberian platform: carbon isotopic evidence. Geol. Mag. 142: 319–325. Archaeocyatha.

Krautter M (1998), Ecology of siliceous sponges: Application to the environmental interpretation of the Upper Jurassic sponge facies (Oxfordian) from Spain. Cuad. Geol. Ibér. 24: 223-239. Hexactinellida.

Larroux C, B Fahey, D Liubicich, VF Hinman, M Gauthier, M Gongora, K Green, G Wörheide, SP Leys, & BM Degnan (2006), Developmental expression of transcription factor genes in a demosponge: insights into the origin of metazoan multicellularity. Evol. Devel. 8: 150-173. Demospongiae.

Lehnert H, R Stone & W Heimler (2005), Two new species of Plakina Schulze, 1880 (Porifera, Plakinidae) from the Aleutian Islands (Alaska, USA),Zootaxa 1068: 27-38. Homoscleromorpha.

Leinfelder RR, W Werner, M Nose, DU Schmid, M Krautter, R Laternser, M Takacs & D Hartmann (1996), Paleoecology, growth parameters and dynamics of coral, sponge and microbolite reefs from the Late Jurassic. In J Reitner, F Neuweiler & FA Gunkel (eds.), Global and Regional Controls on Biogenic Sedimentation. I. Reef Evolution. Research Reports. Göttinger Arb. Geol. Paläont., Sb2, 227-248. Irregulares, Stromatoporoidea.

Leys SP (2003), The significance of syncytial tissues for the position of the Hexactinellida in the Metazoa. Integr. Comp. Biol. 43: 19-27. Hexactinellida.

Leys SP, E Cheung & N Boury-Esnaulty (2006), Embryogenesis in the glass sponge Oopsacas minuta: Formation of syncytia by fusion of blastomeres. Integr. Comp. Biol., 46: 104-117. Hexactinellida, Porifera.

Leys SP, TW Cronin, BM Degnan & JN Marshall (2002), Spectral sensitivity in a sponge larva. J. Comp. Physiol. A 188: 199-202. Demospongiae.

Leys SP & BM Degnan (2001), Cytological basis of photoresponsive behavior in a sponge larva.  Biol. Bull. 201: 323-338. Demospongiae.

Leys SP & AV Ereskovsky (2006), Embryogenesis and larval differentiation in sponges. Can. J. Zool. 84: 262–287. Demospongiae, Homoscleromorpha, Irregulares.

Li C-W, J-Y Chen & T-E Hua (1998), Precambrian sponges with cellular structures. Science 279: 879-882. Demospongiae, Porifera.

Maldonado M (2004), Choanoflagellates, choanocytes, and animal multicellularity. Invert. Bio. 123: 1-22. Demospongiae, Homoscleromorpha.

Maldonado M, M Durfort, DA McCarthy & CM Young (2003), The cellular basis of photobehavior in the tufted parenchymella larva of demosponges. Marine Biol. 143: 427-441. Notes.

Maldonado M, SB George, CM Young & I Vaquerizo (1997), Depth regulation in parenchymella larvae of a demosponge: relative roles of skeletogenesis, biochemical changes and behavior, Mar. Ecol. Progr. Ser. 148: 115-124. Notes.

Maldonado M & A Riesgo (2007), Intra-epithelial spicules in a homosclerophorid sponge. Cell Tissue Res. 328: 639-650. Demospongiae, Homoscleromorpha.

Maloof AC, DP Schrag, JL Crowley & SA Bowring 2006), An expanded record of Early Cambrian carbon cycling from the Anti-Atlas margin, Morocco. Can J. Earth Sci. 42: 2195-2216. Archaeocyatha.

Medina M, AG Collins, JD Silberman & ML Sogin 2001), Evaluating hypotheses of basal animal phylogeny using complete sequences of large and small subunit rRNA. Proc. Nat. Acad. Sci. (USA) 98: 9707–9712. Demospongiae, Hexactinellida.

Meert JG & BS Lieberman (2004), A palaeomagnetic and palaeobiogeographic perspective on latest Neoproterozoic and Early Cambrian tectonic events. J. Geol. Soc. Lond., 161: 477-487. Archaeocyatha.

Miller, A. J. (2004), A revised morphology of Cloudina with ecological and phylogenetic implications. unpublished mss. Irregulares.

Misevic GN, Y Guerardel, LT Sumanovski, M-C Slomianny, M Demarty, C Ripoll, Y Karamanos, E Maes, O Popescu & G Strecker 2004), Molecular recognition between glyconectins as an adhesion self-assembly pathway to multicellularity. J. Biol. Chem., 279: 15579-15590. Porifera.

Moore RC, CG Lalicker & AG Fischer (1952), Invertebrate Fossils. McGraw-Hill. Archaeocyatha.

Müller WEG (2003), The origin of metazoan complexity: Porifera as integrated animals. Integr. Comp. Biol., 43: 3–10. Porifera.

Müller WEG, OV Kaluzhnaya, SI Belikov, M Rothenberger, HC Schröder, A Reiber, JA Kaandorp, B Manz, D Mietchen, & F Volke 2006), Magnetic resonance imaging of the siliceous skeleton of the demosponge Lubomirskia baicalensis. J. Struct. Biol. 153: 31-41. Demospongiae.

Müller WEG, J-H Li, HC Schröder, L Qiao& X-H Wang 2007), The unique skeleton of siliceous sponges (Porifera; Hexactinellida and Demospongiae) that evolved first from the Urmetazoa during the Proterozoic: a review. Biogeosciences 4: 219-232. Archaeocyatha, Demspongiae, Hexactinellida, Porifera.

Muricy G, N Boury-Esnault, C Bézac & J Vacelet (1998), Taxonomic revision of the Mediterranean Plakina Schulze (Porifera, Demospongiae, Homoscleromorpha).Zool. J. Linn. Soc. 124: 169-203. Homoscleromorpha.

Nichols SA, W Dirks, JS Pearse & N King (2006), Early evolution of animal cell signaling and adhesion genes. Proc. Nat. Acad. Sci. (USA) 103: 12451–12456. Homoscleromorpha, Porifera.

Patterson, DJ (1999), The diversity of eukaryotes. Amer. Naturalist 65: S96-S124. Demospongiae, Notes.

Perejón A & E Moreno-Eiris (2006), Arqueociatos de España: Bioconstrucciones y puesta al día de la sistemática y la bioestratigrafía. Bol. R. Soc. Esp. Hist. Nat. (Sec. Geol.), 101: 105-145. Archaeocyatha, Irregulares.

Peterson KJ, B Waggoner, & JW Hagadorn (2003), A fungal analog for Newfoundland Ediacaran fossils? Integr. Comp. Biol., 43: 127–136. Porifera.

Pushkin A & I Kurtz (2006), SLC4 base HCO₃^-, CO₃^2-) transporters: classification, function, structure, genetic diseases, and knockout models. Am. J. Physiol. Renal Physiol. 290: F580–F599. Demospongiae.

Reitner J & TS Engeser (1987), Skeletal structures and habitats of Recent and fossil Acanthochaetetes subclass Tetractinomorpha, Demospongiae, Porifera). Coral Reefs 6: 13-18. Stromatoporoidea.

Riesgo A, M Maldonado & M Dufort (2007), Dynamics of gametogenesis, embryogenesis, and larval release in a Mediterranean homosclerophorid demosponge. Mar. Freshw. Res. 58: 398-417. Homoscleromorpha.

Riesgo A, C Taylor & SP Leys (2007), Reproduction in a carnivorous sponge: the significance of the absence of an aquiferous system to the sponge body plan. Evol. Devel. 9: 618-631. Demospongiae, Homoscleromorpha, Porifera Cladogram.

Rokas, A, N King, J Finnerty & SB Carroll (2003), Conflicting phylogenetic signals at the base of the metazoan tree. Evol. Devel. 5: 345-359. Demospongiae, Hexactinellida.

Rokas A, D Krüger & SB Carroll (2005), Animal evolution and the molecular signature of radiations compressed in time. Science 310: 1933-1938. Demospongiae.

Rowland SM (2001), Archaeocyatha: A history of phylogenetic interpretation. J. Paleontol., 75: 1065-1078. Archaeocyatha, Irregulares, Stromatoporoidea.

Schlagintweit F (2005), Consinocodium japonicum Endo, 1961 from the Upper Jurassic of the Northern Calcareous Alps of Austria: not a siphonous green alga, but a coralline sponge. Rev. Paléont. Genève 24: 533-540. Stromatoporoidea.

Shmitt S (2002), Molekulare Phylogenie der Ordnung Verongida (Porifera). Unpub. Ph.D. Diss. Bayerische Julius-Maximilians-Universität Würzburg, 102 pp. Homoscleromorpha, Tetractinomorpha.

Schröder HC, S Perović-Ottstadt, M Rothenberger, M Wiens, H Schwertner, R Batel, M Korzhev, IM Müller & WEG Müller (2004), Silica transport in the demosponge Suberites domuncula: Fluorescence emission analysis using the PDMPO probe and cloning of a potential transporter. Biochem. J. 381: 665–673. Demospongiae.

Schütze J, A Krasko, MR Custodio, SM Efremova, IM Müller & WEG Müller (1998), Evolutionary relationships of Metazoa within the eukaryotes based on molecular data from Porifera. Proc. R. Soc. Lond. B 266: 63-73. Porifera.

Simionato E, V Ledent, G Richards, M Thomas-Chollier, P Kerner, D Coornaert, BM Degnan & M Vervoort (2007), Origin and diversification of the basic helix-loop-helix gene family in metazoans: Insights from comparative genomics. BMC Evol. Bio. 7: 33. Homoscleromorpha, Porifera.

Sperling EA, D Pisani & Peterson (2006), Poriferan paraphyly and its implications for Precambrian palaeobiology. In P Vickers-Rich & P Komarower (eds.) The Rise and Fall of the Ediacaran Biota. Geol. Soc. Lond. Spec. Publ. 286: 355–368. pdf Archaeocyatha, Demospongiae, Hexactinellida, Homoscleromorpha, Porifera, Porifera Dendrogram, Porifera - Index page.

Stanley, GD (2003), The evolution of modern corals and their early history. Earth-Sci. Rev. 60: 195-225. Stromatoporoidea.

Tapanila L & LE Holmer (2006), Endosymbiosis in Ordovician–Silurian corals and stromatoporoids: a new lingulid and its trace from Eastern Canada. J. Paleont. 80:750-759. Stromatoporoidea.

Taylor PD & MA Wilson (2003), Palaeoecology and evolution of marine hard substrate communities. Earh-Science Rev. 62: 1-103. Demospongiae, Irregulares, Stromatoporoidea.

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Tiwari M, CC Pant & VC Tewari (2000), Neoproterozoic sponge spicules and organic-walled microfossils from the Gangolihat Dolomite, Lesser Himalaya, India. Curr. Sci. 79:651-654. Hexactinellida, Porifera.

Uriz M-J (2006), Mineral skeletogenesis in sponges. Can. J. Zool. 84: 322–356. Homoscleromorpha.

Vishnevskaya, V, A Pisera & G Racki (2002), Siliceous biota (radiolarians and sponges) and the Late Devonian biotic crisis: The Polish reference. Acta Pal. Pol. 47: 211–226. Hexactinellida, Porifera.

Wang X & DV Lavrov (2007), Mitochondrial genome of the homoscleromorph Oscarella carmela (Porifera, Demospongiae) reveals unexpected complexity in the common ancestor of sponges and other animals. Mol. Biol. Evol. 24: 363–373. Porifera.

Weaver JC, LI Pietrasanta, N Hedin, BF Chmelka, PK Hansma & DE Morse (2003), Nanostructural features of demosponge biosilica. J. Struct. Biol. 144: 271-281. Demospongiae, Irregulares.

Webby BD (2004), Stromatoporoids in BD Webby, F Paris, ML Droser & IG Percival (eds.), The Great Ordovician Biodiversification Event. Columbia Univ. Press, pp. 112-118. Stromatoporoidea.

Weiner S & L Addadi (1997), Design strategies in mineralized biological materials.  J. Mater. Chem., 7: 689–702. Demospongiae.

Wendt J & B Kaufmann (2006), Middle Devonian (Givetian) coral-stromatoporoid reefs in West Sahara (Morocco). J. Afr. Earth Sci. 44: 339-350. Stromatoporoidea.

Wood R (1998), The ecological evolution of reefs. Annu. Rev. Ecol. Syst., 29: 179–206. Archaeocyatha, Hexactinellida, Porifera, Stromatoporoidea.

Wrona R (2004), Cambrian microfossils from glacial erratics of King George Island, Antarctica. Acta Pal. Pol. 49: 13-56. Archaeocyatha.

Yahel G, F Whitney, HM Reiswig, DI Eerkes-Medrano & SP Leys (2007), In situ feeding and metabolism of glass sponges (Hexactinellida, Porifera) studied in a deep temperate fjord with a remotely operated submersible. Limnol. Oceanor. 52: 428-440. Hexactinellida.

Yang J, M Adamian & T-S Li (2006), Rootletin interacts with C-Nap1 and may function as a physical linker between the pair of centrioles/basal bodies in cells. Mol. Biol. Cell 17: 1033-1040. Demospongiae.

Yang J, J-G Gao, M Adamian, X-H Wen, B Pawlyk, L Zhang, MJ Sanderson, J Zuo, CL Makino, & T-S Li (2005), The ciliary rootlet maintains long-term stability of sensory cilia. Mol. Cell. Biol. 25: 4129-4137. Demospongiae.

Yang J, X-Q Liu, G-H Yue, M Adamian, O Bulgakov & T-S Li (2002), Rootletin, a novel coiled-coil protein, is a structural component of the ciliary rootlet. J. Cell Biol. 159: 431-440. Demospongiae.

Yin C-G, S Bengston & Z Yue (2004), Silicified and phosphatized Tianzhushania, spheroidal microfossils of possible animal origin from the Neoproterozoic of South China. Acta Pal. Pol. 49: 1-12. Demospongiae.

Notes

[1] For an explanation of mtDNA phylogenies, and an interminable diatribe about their weaknesses, see Insectivora. We've been railing against the use of mtDNA phylogenies almost as long as people have been doing them. As it turns out, we were mostly correct (although not always for the right reasons). This is rare enough that we've made the most of the opportunity -- perhaps our last chance to kick this particular dead horse.

[2] But not all. Schütze et al. (1999) note that choanodermal cells of Calcarea lack the distinctive collar of choanoflagellates, and that many details of sponge ultrastructure differ from those of these probable poriferan ancestors.

[3] We, of course, take issue with this point because we regard spicule formation as closely related in all sponge taxa, as discussed earlier. In fact, we assert elsewhere that spicules were developed exactly once. However, we tend to agree that chancelloriids are indeed sponges, largely for the other reasons cited by Sperling et al. (2006).

[4] Oscarella is actually aspiculate. The Homoscleromorpha in general have silicate spicules.

[5] The UCMP site cites to Reitner J (1990), Polyphyletic origin of the "Sphinctozoans" in K Rutzler (ed.), New Perspectives in Sponge Biology, Proceedings of the Third International Conference on the Biology of Sponges (Woods Hole). Smithsonian Institution Press, pp. 33-42.  However, we have not read this paper.

[6] Grotzinger et al. cite to Grant SWF (1990), Shell structure and distribution of Cloudina, a potential index fossil for the terminal Proterozoic. Am. J. Sci. 290A: 261–294 as their basic text on Cloudina.

[7] We expect this statement to become obsolete very quickly.

[8] Archaeolynthus could also assume a growth pattern of branching, tube-like structures, somewhat like Figures A and B.

[9] From the First Phillipic of Demosthenes, directed against Phillip of Macedon in 351 B.C. (Middle Holocene of Europe).

[10] "Each PCR product was sequenced from a minimum of two clones [so they stopped after two if the sequences agreed?]; when contradictions in the sequences of several clones could not be resolved [how would one resolve them?], the corresponding positions were coded according to the UPIAC code. The two strands were sequenced for the main part of the sequence length, with special attention ["main part"? What is non-"special attention"?] to the D2 domain where strong secondary structures of the molecule cause compressions in the sequence migration [how do they know it's restricted to D2?]." Chombard et al. (1997: 361). What this might mean is: "We had some troubling problems with inconsistency, and ran out of time/funding, but we think the errors were not too significant."  Quite possibly, that conclusion is correct. On the other hand, it isn't the sort of painstacking accuracy we might expect with the improved methods available today -- nor the kind of thing on which we should rely for mapping fundamental branches in the phylogeny of the Metazoa.

[11] As do certain nucleariid amoebae (Patterson, 1999), also thought to be on or around the metazoan stem. However, this may well be a convergent specialization. For the moment, we will ignore the nucleariids.

[12] It is interesting, if probably irrelevant, that some demosponge larvae, which lack a cross-striated ciliary rootlet, also have a ciliary "foot" which does appear to have cross-striations. Maldonado et al. (2003).

[13] Prof. Leys has expressed the view that the "plugged pores" of hexactinellids are not at all like Fungi. We think she's probably correct on this, but opinions vary.

[14] We discuss three of these features (basement membrane, flagellum, and embryonic development) in much more detail in connection with the Demospongiae. As discussed in that section, and in the section on Homoscleromorpha, none of these characters support a supposed clade composed of Calcarea + Homoscleromorpha + Eumetazoa, various papers to the contrary notwithstanding.

[15] One bizarre phylogenetic possibility raised by this similarity is that spicules evolved as a by-product of embryogenesis. Demoponge embryos frequently have spicules and, oddly enough, those spicules may be shed at metamorphosis. Maldonado et al. (1997). Sponges are also usually viviparous. Thus, we might imagine a Cloudina-like form, with internally growing embryos. Some embryos are released as young (and later shed their "baby spicules"), while others are retained to transdifferentiate into internal supports. This is pure speculation. But, in sponges, nearly anything is possible; and this would account for two sponge peculiarities at once. 

[16] It's a bit hard to put any particular date on Prof. Claude Lévi. His first publication was in 1951.  He retired from the MNHN (Paris) in about 2000, but we understand that he is still consulted on particularly difficult taxonomic calls. 

[17] Oddly, this concern for contamination has never been addressed in the published sponge sequence phylogenies. Perhaps it is of less concern in such cases, for some reason.

[18] Briefly, (1) these polyketides look as if they may be derivatives of Δ^5,9unsaturated fatty acids. These are better dealt with on their own terms and are discussed below.  2) Some members of this family are branched, which is rare among animals, but more common in bacterial metabolites. (3) The creation of peroxy derivatives is not only unusual, particularly for animals, but means that the resulting substance is probably quite unstable -- a bad thing when one is looking for potential presence/absence characters. For what it may be worth, our suspicion is that peroxypolyketides are an incidental by-product of the reaction of sponge enzymes evolved for the metabolism of Δ^5,9unsaturated fatty acids with improper substrates, perhaps derived from fungi or dietary bacteria.   

[19]  (1) Reproductive biology reminds us of all the incredibly tedious stuff that bored us into catatonia during high school biology. (2) Characters of reproductive biology are wildly variable, seldom carry much long-range phylogenetic signal, and virtually never fossilize. (3) The subject requires a clear understanding of endocrinology and population genetics, both of which we lack because of item #1. 4) Finally, and perhaps most significantly, the subject requires a vocabulary which causes content censor programs to go into cardiac arrest and, conversely, attracts attention to the site from various types we like to avoid.