Revision of the genus Evansula T. Scott, 1906 (Copepoda, Harpacticoida, Cylindropsyllidae) with a description of three new species
Huys, R.; Conroy-Dalton, S. (2006). Revision of the genus Evansula T. Scott, 1906 (Copepoda, Harpacticoida, Cylindropsyllidae) with a description of three new species. Zool. J. Linn. Soc. 147(4): 419-472. http://dx.doi.org/10.1111/j.1096-3642.2006.00227.x In: Zoological Journal of the Linnean Society. Academic Press: London. ISSN 0024-4082; e-ISSN 1096-3642, more |  |
| Keywords | Biogeny > Phylogeny
Classification > Taxonomy
Fouling
Taxa > Species > New taxa > New species
Canthocamptidae Brady, 1880 [WoRMS]; Evansula cumbraensis Huys & Conroy-Dalton, 2006 [WoRMS]; Evansula polaris Huys & Conroy-Dalton, 2006 [WoRMS]; Evansula spinosa Huys & Conroy-Dalton, 2006 [WoRMS]
Marine/Coastal |
| Authors | | Top | - Huys, R., more
- Conroy-Dalton, S.
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| Abstract | A revision of the marine mesopsammic genus Evansula T. Scott (Copepoda, Harpacticoida, Cylindropsyllidae) is presented. Analysis of type and newly collected material, using both light and scanning electron microscopy, revealed that the genus consists of a complex of morphologically similar species, which frequently occur sympatrically. Redescriptions are provided for E. incerta T. Scott (type), E. pygmaea T. Scott and E. arenicola Nicholls, and published records are reviewed. Three new species, previously confused with either E. incerta (E. polaris sp. nov., E. spinosa sp. nov.) or E. pygmaea (E. cumbraensis sp. nov.) are described from north-western European waters. Scanning electron microscopy revealed that the reported plumosity of certain setae on the P5 is, in reality, a biofouling artefact caused by site-specific, epibiotic, filamentous bacteria. Evansula is the only cylindropsyllid genus that has retained inner setae on the P4 endopod and exhibits the ancestral complement of seven setae on the male P5. Its early divergence within the family is further evidenced by the absence of two sexually dimorphic structures in the male, the apomorphic presence of which supports the monophyly of the residual genera: (1) the spinous process on the P2 basis, and (2) the secretory pore on the anterior surface of the male P3 exp-2. The Cylindropsyllidae has recently been relegated to subfamilial status, and as a result was subsumed within the Canthocamptidae. The evidence employed to justify this course of action is critically evaluated and proven essentially unsound. Consequently, the Cylindropsyllidae is reinstated here as a valid taxon. |
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