Rhombocorniculum

Rhombocorniculum Temporal range: Cambrian Stage 2–Cambrian Stage 3 [1] PreꞒ Ꞓ O S D C P T J K Pg N
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
(unranked):	Panarthropoda
Phylum:	† "Lobopodia"
Family:	† Hallucigeniidae
Genus:	† Rhombocorniculum Walliser, 1958 [2]

Rhombocorniculum is a species of small shelly fossil comprising twisted ornamented cones. It has been described from the Comley Limestone and elsewhere. R. cancellatum straddles the Atdabanian/Botomian boundary. ^[1] The structure of its inner layer suggests that its phosphatic fibres formed within a flexible organic matrix. ^[3]

Taxonomy

Three species are recognized — in stratigraphic succession: R. insolutum, R. cancellatum (=R. walliseri), and R. spinosus (=Rushtonites spinosus). ^[4] Landing (1995) refers R. insolutum to the strictocorniculids, along with Rushtonites . ^[3] Hinz (1987) considers insolutum to fall within the variability seen in cancellatum.

Affinity

Based on details of the ornament and construction, Rhombocorniculum is interpreted as the spines of a Hallucigenia -like lobopodian worm. ^[5]

See also

• Mongolitubulus

References

1. Brasier, M. D. (1986). "The succession of small shelly fossils (especially conoidal microfossils) from English Precambrian–Cambrian boundary beds". Geological Magazine. 123 (3): 237–256. Bibcode:1986GeoM..123..237B. doi:10.1017/S0016756800034737.
2. Otto H. Walliser (1958). "Rhombocorniculum comleyense n. gen., n. sp". Paläontologische Zeitschrift. 32 (3–4): 176–180. Bibcode:1958PalZ...32..176W. doi:10.1007/BF02989029.
3. Landing, E. (May 1995). "Upper Placentian-Branchian Series of Mainland Nova Scotia (Middle-Upper Lower Cambrian): Faunas, Paleoenvironments, and Stratigraphic Revision". Journal of Paleontology. 69 (3): 475–495. Bibcode:1995JPal...69..475L. doi:10.1017/S0022336000034879. JSTOR   1306322.
4. Brasier, M. D. (1989). Towards a biostratigraphy of the earliest skeletal biotas. In J. W. Cowie & M. D. Brasier (Eds.), The Precambrian-Cambrian boundary (pp. 117–165). Oxford: Clarendon Press.
5. Caron, J. -B.; Smith, M. R.; Harvey, T. H. P. (2013). "Beyond the Burgess Shale: Cambrian microfossils track the rise and fall of hallucigeniid lobopodians". Proceedings of the Royal Society B: Biological Sciences. 280 (1767): 20131613. doi:10.1098/rspb.2013.1613. PMC   3735267 . PMID   23902914.