Systematics of the Acanthoparyphinae (Trilobita), with species from the Silurian of Arctic Canada

Jonathan M Adrain

doi:10.1017/s0022336000040403

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Systematics of the Acanthoparyphinae (Trilobita), with species from the Silurian of Arctic Canada

Journal article

Peer reviewed

Systematics of the Acanthoparyphinae (Trilobita), with species from the Silurian of Arctic Canada

Jonathan M Adrain

Journal of paleontology, Vol.72(4), pp.698-718

07/1998

DOI: 10.1017/s0022336000040403

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Abstract

Cladistic analysis of the trilobite subfamily Acanthoparyphinae Whittington and Evitt, 1954, yields an explicit hypothesis of relationship for the group. All Silurian species together form a robustly supported monophylum including the genera Hyrokybe Lane, 1972, Parayoungia Chatterton and Perry, 1984, and Youngia Lindstrom, 1885. Sister to this is the Ordovician type species of Acanthoparypha Whittington and Evitt, 1954. Remaining species that have historically been assigned to either Acanthoparypha or Pandaspinapyga Esker and Levin, 1964, form a rather labile paraphylum. Nevertheless, the entire group thus identified is definitely monophyletic, and supported by several prominent synapomorphic character-states. The basal structure and basal node of the subfamily are more difficult to assess. The relationships of the genera Hammannopyge Pribyl, Vanek, and Pek, 1985, Holia Bradley, 1930, and Nieszkowskia Schmidt, 1881, need to be addressed within the wider context of the family as a whole. The traditional assignment of Holia to the acanthoparyphines is followed. Wenlock acanthoparyphines from the Cape Phillips Formation of the central Canadian Arctic islands include several species of Hyrokybe and Parayoungia. They are similar to, and in one case conspecific with, coeval forms to the southwest in the southern Mackenzie Mountains. Five species are new: Holia glabra, Hyrokybe lightfooti, Hyrokybe youngi, Hyrokybe mitchellae, and Parayoungia mclaughlini. At least four other potentially new species are reported in open nomenclature.

Acanthoparyphinae

Arctic Archipelago

Arthropoda

biozones

Canada

Cape Phillips Formation

cladistics

Franklin District Northwest Territories

Hammannopyge

Hammannopygy unica

Holia glabra

Hyrokybe

Hyrokybe julli

Hyrokybe lightfooti

Hyrokybe mitchellae

Hyrokybe youngi

Invertebrata

Invertebrate paleontology

lower Paleozoic

morphology

new taxa

Nieszkowskia

Northwest Territories

Paleozoic

Parayoungia mclaughlini

phylogeny

revision

Silurian

statistical analysis

Trilobita

Trilobitomorpha

Western Canada

Details

Title: Subtitle: Systematics of the Acanthoparyphinae (Trilobita), with species from the Silurian of Arctic Canada
Creators: Jonathan M Adrain - American Museum of Natural History
Resource Type: Journal article
Publication Details: Journal of paleontology, Vol.72(4), pp.698-718
Publisher: Paleontological Society
DOI: 10.1017/s0022336000040403
ISSN: 0022-3360
eISSN: 1937-2337
Language: English
Date published: 07/1998
Academic Unit: Earth and Environmental Sciences
Record Identifier: 9984229299402771

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