Micrina Explained

Micrina is an extinct genus of tommotiids with affinities to brachiopods.^[1]

Micrina can be considered a stem group brachiopod based on its larval shell^[2]

Its microstructure is very brachiopod like^[3] and its adult morphology is similarly bivalved,^[4] even though it was once thought to be halkieriid-like.^[5]

Micrina is quite similar to Mickwitzia in terms of shell microstructure. The two genera are evidently closely related.

Species

• M. etheridgei (Tate, 1892)
• M. pusilla Gravestock et al., 2001
• M. ridicula (Barskova, 1988)
• M. xiaotanensis Li & Xiao, 2004^[6]

Notes and References

1. 1992 . Two new species of the Cambrian genus Mickwitzia. Journal of Paleontology . McMenamin, M. A. S. . 66 . 2 . 173–182 . 10.1017/S0022336000033680 . 1305903 . 132405917.
2. Holmer L. E., Skovsted C. B., Larsson C., Brock G. A., Zhang Z. . 2011 . First record of a bivalved larval shell in Early Cambrian tommotiids and its phylogenetic significance . Palaeontology . 54 . 2 . 235–239 . 10.1111/j.1475-4983.2010.01030.x. free .
3. Balthasar U., Skovsted C. B., Holmer L. E., Brock G. A. . 2009 . Homologous skeletal secretion in tommotiids and brachiopods . Geology . 37 . 12 . 1143–1146 . 10.1130/g30323a.1. 2009Geo....37.1143B .
4. Holmer L. E., Skovsted C. B., Brock, Valentine J. L., Paterson J. R. . 2008 . The Early Cambrian tommotiid Micrina, a sessile bivalved stem group brachiopod . Biol. Lett. . 4 . 6 . 724–728 . 10.1098/rsbl.2008.0277. 18577500 . 2614141 .
5. Holmer L. E., Skovsted C. B., Williams A. . A stem group brachiopod from the lower Cambrian: support for a Micrina (Halkieriid) ancestry . Palaeontology . 2002 . 45 . 5 . 875–882 . 10.1111/1475-4983.00265.
6. Li G.-X., Xiao S.-H. . 2004 . Tannuolina and Micrina (Tannuolinidae) from the Lower Cambrian of Eastern Yunnan, South China, and Their Scleritome Reconstruction . J. Paleontol. . 78 . 5. 900–913 . 10.1666/0022-3360(2004)078<0900:TAMTFT>2.0.CO;2 . 4094916. 131286565 .