Astraeospongium
| Astraeospongium Temporal range:
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Scientific classification 
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| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Porifera |
| Class: | Calcarea |
| Family: | †Astraeospongiidae |
| Genus: | †Astraeospongium Roemer, 1854[1] |
| Type species | |
| Blumenbachium meniscum[2] Roemer, 1848
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| Species | |
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| Synonyms[3] | |
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Astraeospongium is a genus of calcareous sponge from the Silurian.[1][4] Known species include A. meniscum and A. patina.
Taxonomy
[edit]The type species of Astraeospongium, A. meniscum, was named by German geologist Ferdinand von Roemer in 1848, and was originally assigned to the bryozoan genus Blumenbachium.[2] In a later publication, Roemer reassigned it to its own genus, Astraeospongium;[1] twelve years later, though, he apparently renamed it to Astraeospongia meniscus.[5] There is no evidence of any argument or intention to change its binomial name, and such a change would be invalid.[6] Thus, Astraeospongium meniscum is the correct binomial name for the type species.[4] Additional species have been named over the years, including A. patina and A. lancifer; the latter has been reassigned to Gondekia, which belongs to Eiffeliidae.[7]
Description
[edit]Astraeospongium as a genus is bowl shaped, with a skeleton composed of star-shaped octatin spicules. Most specimens range from 3.5–5 cm (1.4–2.0 in) though may range from 3–9 cm (1.2–3.5 in).[4] In A. meniscum, spicules are 6–7 mm (0.24–0.28 in), though in A. patina, they are only 1 mm (0.039 in).[8] The youngest spicules are found at the upper surface, particularly close to the rim, and are fairly easily distinguished. About 1–2 mm (0.039–0.079 in) from the base, they begin to recrystalise and are cemented together. In the middle, they fuse into a massive, calcareous basal skeleton that lacks open spaces or channels. It has inferred that soft tissues only occupied the uppermost part of the basal skeleton.[4]
References
[edit]- ^ a b c Roemer, F. 1854. Palaeo-Lethaea, Kohlen-Periode. In: Bronn, H.G. & Rohmer, F. "Lethaea Geognostica". 1 (2): 1–788. Stuttgart.
- ^ a b Roemer F. 1848. Über eine neue Art der Gattung 'Blumenbachium' (König) und mehrere unzweifelhafte Spongien in obersilurischen Kalkschichten der Grafschaft Decatur im Staate Tennessee in Nord-Amerika. Neues Jahrbuch für Mineralogie, Geognosie, Geologie und Petrefaktenkunde. 680–686. Stuttgart.
- ^ Astraeospongium in the Paleobiology Database
- ^ a b c d Mehl, Dorte; Reitner, Joachim (1996). "Observations on Astraeospongium meniscum (Roemer, 1848) from the Silurian of West Tennessee: Constructional morphology and palaeobiology of the Astraeospongiidae (Calcarea, Heteractinellidae)" (PDF). Berliner Geowissenschaftliche Abhandlungen. 18: 243–255.
- ^ Roemer F. 1860. Die silurische Fauna des westlichen Tennessee. Eine palaeontologische Monographie. 100. Eduard Trewendt-Verlag, Breslau.
- ^ Rietschel, Siegfried (1 April 1968). "Die octactinellida und ihnen verwandte paläozoische Kalkschwämme (Porifera, Calcarea)". Paläontologische Zeitschrift (in German). 42 (1): 13–32. Bibcode:1968PalZ...42...13R. doi:10.1007/BF02987126.
- ^ Rigby, J. Keith (1 January 1991). "The new Devonian (Givetian) heteractinid sponge Gondekia from Ontario, Canada, and evolution of the astraeospongiids and eiffeliids". Journal of Paleontology. 65 (1): 38–44. Bibcode:1991JPal...65...38R. doi:10.1017/S0022336000020175.
- ^ Rhebergen, Freek (6 August 2009). "Revision of the species Astraeospongium patina Roemer, 1861, based on Ordovician bedrock specimens from Estonia". GFF. 129 (1): 17–22. doi:10.1080/11035890701291017. ISSN 1103-5897.