Key:  Family Yoldiidae

Taken primarily from  Kozloff, 1987, 1996 p. 268 (Copyright 1987, 1996, University of Washington Press.  Used in this web page by permission of University of Washington Press)

Jump to:
Lower taxonomic level	Main Page	Alphabetic Index	Systematic Index	Glossary

1a	Shell swollen, posterior end broadly truncate	Yoldia (Megayoldia) thraciaeformis
1b	Shell rather flat, not swollen; posterior end not truncate	2
2a	Concentric sculpture not coinciding with growth lines (there are slight concentric ridges that cross the growth lines) (Y. scissurata in Kozloff key)	Yoldia seminuda
2b	Without any concentric sculpture other than growth lines	3
3a	Umbones slightly posterior to the middle; length twice the height	Yoldia (Yoldia) amygdalea
3b	Umbones at the middle; length slightly less than twice the height	Yoldia (Yoldia) myalis

  Yoldia (Yoldia) myalis
  Yoldia seminuda