Where: Vastergotland, Sweden (58.3° N, 13.5° E: paleocoordinates 41.1° S, 19.6° W)

• small collection-level geographic resolution

When: Agnostus pisiformis zone, Alum Shale Formation, Maentwrogian (497.0 - 496.8 Ma)

• formation-level stratigraphic resolution

Environment/lithology: lithified, concretionary shale

Preservation: replaced with phosphate

Collection methods: bulk,

• The larva are preserved as phosphatized soft parts in anthraconite (orsten) concretions. Simplicity of form prevents further classification of larvae. Larvae A2 lacks dorsal outgrowhths unlike A1 (most significant distinction). A2 is 10-20% larger in structure, but idea of successive growth stages of the same animal is dismissed by a better defined caudal end in A1.

Primary reference: D. Walossek and K. J. Muller. 1989. A second type A-nauplius from the Upper Cambrian ''Orsten' of Sweden. Lethaia 22:301-306 [M. Patzkowsky/P. Borkow/M. Uhen]more details

Purpose of describing collection: taxonomic analysis

PaleoDB collection 7906: authorized by Mark Patzkowsky, entered by Phil Borkow on 07.06.2000

Creative Commons license: CC BY (attribution)