Pachychelium Stephensen 1925
Creators
Description
Pachychelium Stephensen, 1925
Pachychelium Stephensen, 1925: 121. ― Schellenberg, 1926: 296. ―Schellenberg, 1931: 18. ―K.H. Barnard, 1932: 75. ―J.L. Barnard, 1969a: 354. ― Lowry, 1984: 99. ― Barnard & Karaman, 1991: 509.
Type species. Pachychelium davidis Stephensen, 1925, by monotypy.
Diagnostic description. Body shape slender. Head lateral cephalic lobe large, narrowly rounded. Antenna 1 peduncular article 1 without posterodistal spine; accessory flagellum article 1 long; [callynophore not known for female]. Mandible with accessory setal row absent; left lamina dentata absent; palp attached distally; palp article 2 broad, article 3 with subparallel margins or distally tapered. Maxilla 1 outer plate setal-teeth smooth, at least one inner row setal-tooth absent; palp absent. Maxilliped inner plate absent; outer plate medium size; palp 3-articulate (article 4 absent). Gnathopod 1 ischium smaller than propodus; corner of palm with simple robust seta or without any robust seta. Gnathopod 2 palm obtuse. Epimeron 3 posteroventral corner broadly rounded. Uropod 3 biramous.
Remarks. With the new species described from the boreal eastern North Pacific and the tropical western South Pacific and the reassignment of some species to Ultimachelium, the distribution of the previously bipolar genus Pachychelium is changed significantly. The sister taxon of Pachychelium appears to be Ultimachelium. The genera differ in the number of articles in the maxillipedal palp (article 4 absent in Pachychelium, large and well developed in Ultimachelium) and in epimeron 3 which has a broadly rounded posteroventral corner in Pachychelium, projecting and narrowly rounded in Ultimachelium.
Species composition. Pachychelium davidis Stephensen, 1925; P. fucaensis sp. nov.; P. tropicalis sp. nov.
Pachychelium antarcticum Schellenberg, 1926, is regarded as an unidentifiable taxon.
Notes
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Linked records
Additional details
Identifiers
Related works
- Is part of
- Journal article: 10.11646/zootaxa.3246.1.1 (DOI)
- Journal article: http://zenodo.org/record/5249007 (URL)
- Journal article: http://publication.plazi.org/id/B959FFAB3625FF89B848092DFF814D73 (URL)
- Is source of
- https://sibils.text-analytics.ch/search/collections/plazi/456087D3363BFF96B8DF0CC9FBDB4CD8 (URL)
Biodiversity
- Family
- Pakynidae
- Genus
- Pachychelium
- Kingdom
- Animalia
- Order
- Amphipoda
- Phylum
- Arthropoda
- Scientific name authorship
- Stephensen
- Taxon rank
- genus
- Taxonomic concept label
- Pachychelium Stephensen, 1925 sec. Lowry & Stoddart, 2012
References
- Stephensen, K. (1925) Crustacea Malacostraca, VI: (Amphipoda, II). Danish Ingolf-Expedition, 3 (9), 101 - 178.
- Schellenberg, A. (1926) Die Gammariden der deutschen Sudpolar-Expedition 1901 - 1903. Deutsche Sudpolar-Expedition, Zoology, 10, 18, 235 - 414.
- Barnard, K. H. (1932) Amphipoda. ' Discovery' Reports, 5, 1 - 326, pl. 1.
- Barnard, J. L. (1969 a) The families and genera of marine gammaridean Amphipoda. United States National Museum Bulletin, 271, 1 - 535.
- Lowry, J. K. (1984) Systematics of the pachynid group of lysianassoid Amphipoda (Crustacea). Records of the Australian Museum, 36 (2), 51 - 105.
- Barnard, J. L. & Karaman, G. S. (1991) The families and genera of marine gammaridean Amphipoda (except marine gammaroids). Records of the Australian Museum, Supplement, 13 (2), 419 - 866.