Published November 18, 2020 | Version v1
Taxonomic treatment Open

Onisimus normani Sars 1891

  • 1. Tromsø Museum, UiT - The Arctic University of Norway, NO 9037 Tromsø, Norway.
  • 2. Ekkerøya, NO 9800 Vadsø, Norway.
  • 3. University museum of Bergen, University of Bergen, PO box 78, NO 5020 Bergen, Norway.

Description

Key to the ‘ normani -group’

The ‘ normani -group’ within Onisimus is characterized by a partly cleft telson, a completely constricted uropod 2, and a peculiar 1 st epimeral plate, with an anterodistal hook (Vader et al. 2005). The group consists of O. normani, O. turgidus, and 2 or 3 taxa closely related to O. turgidus, but strongly deviating in the arrangement of the setal teeth on the outer plate of maxilla 1. Material belonging to these taxa has been found in the W Atlantic Ocean, near Greenland and in the NW Pacific (Johnsen 2001). Most (or possibly all) species in this group appear to be obligate associates of sea anemones, a trait absent in all other Onisimus species. In Norwegian waters there are two species in this group, O. normani in W Norway north to Andfjorden, and O. turgidus in N Norway and the Barents Sea. They can be distinguished as follows:

1. Pereopod 1 palm oblique, propodus subrectangular. Uropod 2 inner ramus with small setae in constriction; uropod 1 outer ramus without spines on inner margin............................................................................................................................................................... Onisimus normani Sars, 1891

– Pereopod 1 palm strongly oblique, propodus triangular. Uropod 2 inner ramus with large spine in constriction; uropod 1 outer ramus with spines on inner margin.... Onisimus turgidus (Sars, 1879)

Notes

Published as part of Vader, Wim, Johnsen, Jan Roger & Tandberg, Anne Helene S., 2020, Onisimus turgidus (Sars, 1879) (Amphipoda, Uristidae), an overlooked amphipod from sea anemones in Northern Norway, pp. 34-50 in European Journal of Taxonomy 724 on page 36, DOI: 10.5852/ejt.2020.724.1155, http://zenodo.org/record/5627470

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Linked records

Additional details

Biodiversity

Family
Uristidae
Genus
Onisimus
Kingdom
Animalia
Order
Amphipoda
Phylum
Arthropoda
Scientific name authorship
Sars
Species
normani
Taxon rank
species
Taxonomic concept label
Onisimus normani Sars, 1891 sec. Vader, Johnsen & Tandberg, 2020

References

  • Vader W., Johnsen J. R. & Berge J. 2005. Studies on the genus Onisimus Boeck, 1871 (Crustacea, Amphipoda, Lysianassoidea, Uristidae), Part I. The brevicaudatus and sextonae species groups. Organisms, Diversity & Evolution 5: 161 - 164, Electr Suppl. 7: 1 - 48. https: // doi. org / 10.1016 / j. ode. 2004.08.002
  • Johnsen J. R. 2001. The taxonomy of Onisimus. MSc thesis, University of TromsO, Norway.
  • Sars G. O. 1879. Crustacea et Pycnogonida nova in itinere 2 do et 3 tio expeditionis norvegicae anno 1877 & 78 collecta (Prodromus descriptionis). Archiv for Mathematik og Naturvidenskaber 4: 427 - 476.