Journal article
Heckethornia, a new genus of dimeropygid trilobites from the Lower Ordovician (Ibexian; Tulean and Blackhillsian) of the Great Basin, western USA
Canadian journal of earth sciences, Vol.46(12), pp.875-914
2009
DOI: 10.1139/E09-060
Abstract
Heckethornia n. gen. is a morphologically striking clade of dimeropygid trilobites known from the Pogonip Group (Ordovician; Ibexian Series, Tulean and Blackhillsian stages) of western Utah and eastern Nevada. It includes seven species based on silicified material. All occur in the Fillmore Formation of western Utah, and four are also known from the Yellow Hill Limestone of eastern Nevada. Diagnostic features of Heckethornia include a highly vaulted exoskeleton with a tall pygidial “wall” made of fused outer pleurae, three pairs of large glabellar spines, two to three pairs of prominent pygidial spines, a single (or paired) large occipital spine(s), and an arc of tubercles on the librigenal field. Cladistic parsimony analysis suggests that the genus comprises two subclades, one including species with a single median occipital spine, and species with paired occipital spines or tubercles in the other. New species are H. smithi, H. hyndeae, H. numani, H. bowiei, H. morrisseyi, and H. ballionae.
Details
- Title: Subtitle
- Heckethornia, a new genus of dimeropygid trilobites from the Lower Ordovician (Ibexian; Tulean and Blackhillsian) of the Great Basin, western USA
- Creators
- Neo E.B. McAdamsJonathan M. Adrain
- Resource Type
- Journal article
- Publication Details
- Canadian journal of earth sciences, Vol.46(12), pp.875-914
- DOI
- 10.1139/E09-060
- ISSN
- 0008-4077
- eISSN
- 1480-3313
- Language
- English
- Date published
- 2009
- Academic Unit
- Earth and Environmental Sciences
- Record Identifier
- 9984229161302771
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