Mutelidae

Spatha rubens, from here.

Belongs within: Mollusca.

The Mutelidae are a family of freshwater clams found from the Cretaceous to the present day, characterised by a greatly reduced dentition in the hinge.

Characters (from Cox et al. 1969): Shell mostly unsculptured; beaks smooth or faintly corrugated, without well-defined remains of embryonic shell; hinge with cardinals only or edentulous, few with secondary taxodont dentition; nacre soft, richly tinted, pallial line rarely with slight posterior sinus. Labial palps large, anal and superanal openings not separated; mantle generally closed behind into separate branchial and anal siphons; marsupium occupying inner gills; lasidium larva composed of three segments, median one bearing single shell.

<==Mutelidae
    |--Castalia cordata A66a
    |--Leila A66a
    |    |--L. blainvilliana A66a
    |    `--L. gigantea A66a
    |--Triquetra A66a
    |    |--T. corrugata A66a
    |    `--T. obliqua A66a
    `--Spatha A66b
         |--S. baikii Adams 1866 A66b
         `--S. rubens A66b

*Type species of generic name indicated

REFERENCES

[A66a] Adams, H. 1866a. List of land and freshwater shells collected by Mr. E. Bartlett on the Upper Amazons, and on the River Ucayali, eastern Peru, with descriptions of new species. Proceedings of the Zoological Society of London 1866: 440-445.

[A66b] Adams, H. 1866b. Descriptions of six new species of shells, and note on Opisthostoma de-Crespignii. Proceedings of the Zoological Society of London 1866: 445-447.

Cox, L. R., N. D. Newell et al. 1969. Treatise on Invertebrate Paleontology pt N. Bivalvia vol. 1. The Geological Society of America, Inc. and The University of Kansas.