†subfamily Xenelasmatinae Ulrich and Cooper 1936 (lamp shell)
Rhynchonellata - Pentamerida - Syntrophiidae
Parent taxon: Syntrophiidae according to A. Williams et al. 2002
Sister taxon: Syntrophiinae
Subtaxa: Rhyselasma Rosella Xenelasma Xenelasmella Xenelasmopsis
Type: Xenelasma
Ecology: stationary epifaunal suspension feeder
Distribution:
• Whiterockian of United States (1: Nevada collection)
• Arenigian of the Russian Federation (1)
• Ordovician of the Russian Federation (2), United States (2: Texas)
• Canadian of United States (1: Maryland)
Total: 7 collections each including a single occurrence