Bathynotus: A key trilobite taxon for global stratigraphic boundary correlation between Cambrian Series 2 and Cambrian Series 3

Modularity of a Cambrian ptychoparioid trilobite cranidium.

Modularity of the cranidium of Crassifimbra? metalaspis, a Cambrian ptychoparioid trilobite, is investigated using landmark-based geometric morphometric methods to gain insight into the integration among morphogenetic processes responsible for shaping the head of an ancient arthropod. Of particular interest is the extent to which the structure of phenotypic integration was governed by direct in...

Rare primitive deuterostomes from the Cambrian (Series 3) of Utah

—The fossil record of early deuterostome history largely depends on soft-bodied material that is generally rare and often of controversial status. Banffiids and vetulicystids exemplify these problems. From the Cambrian (Series 3) of Utah, we describe specimens of Banffia episoma n. sp. (from the Spence Shale) and Thylacocercus ignota n. gen. n. sp. (from the Wheeler Formation). The new species ...

Mass-occurrence of oncoids at the Cambrian Series 2–Series 3 transition: Implications for microbial resurgence following an Early Cambrian extinction

Systematic revision of the trilobite genera Laudonia and Lochmanolenellus (Olenelloidea) from the lower Dyeran (Cambrian Series 2) of western Laurentia.

The olenelloid trilobite genus Laudonia Harrington, 1956 was thought to occur widely along the Cordilleran margin of Laurentia in lowermost Dyeran strata (Cambrian Series 2). However, supposed occurrences in the Rosella Formation (Cassiar Mountains, northern British Columbia), the Mural Formation (Cariboo Mountains, east-central British Columbia) and the Poleta Formation (Nevada)--re-examined, ...

A Cambrian peak in morphological variation within trilobite species.

Morphological variation within species is a raw material subject to natural selection. However, temporal change in morphological diversity has usually been studied in terms of variation among rather than within species. The distribution of polymorphic traits in cladistic character-taxon matrices reveals that the frequency and extent of morphological variation in 982 trilobite species are greate...