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A review of Ellescus (Coleoptera: Curculionidae) in North America: new species and synonyms revealed through integrative taxonomy

Published online by Cambridge University Press:  12 April 2023

Jake H. Lewis*
Affiliation:
Environmental Science and Informatics Section, Okinawa Institute of Science and Technology, 1919-1 Tancha, Onna-son, Kunigami-gun, Okinawa, 904-0495, Japan Department of Natural History, New Brunswick Museum, 277 Douglas Avenue, Saint John, New Brunswick, E2K 1E5, Canada
Robert S. Anderson
Affiliation:
Beaty Centre for Species Discovery, Canadian Museum of Nature, 1740 Chemin Pink, Gatineau, Quebec, J9J 3N7, Canada
*
*Corresponding author. Email: jake-lewis@oist.jp

Abstract

A combination of morphological and molecular techniques were used to revise the genus Ellescus Dejean, 1821 (Coleoptera: Curculionidae: Ellescini) in North America. Four valid species of Ellescus are documented from the Nearctic Region. These are the widespread, hypervariable E. ephippiatus (Say, 1831), the Holarctic E. bipunctatus (Linnaeus, 1758) (of which E. borealis (Carr, 1920) new synonym is found to be a new junior synonym), the west coast endemic E. californicus (Casey, 1885) (resurrected from synonymy with E. ephippiatus (Say, 1831)), and the temperately distributed E. michaeli new species. A neotype is designated for E. bipunctatus. The European species, E. scanicus (Paykull, 1792), is determined to have been erroneously reported from North America. An illustrated identification key, distributional data, and DNA sequences (CO1, ITS2) are provided to facilitate identification of the Ellescus species in North America. Notably, CO1 failed to delineate E. ephippiatus and E. michaeli, but the faster-evolving ITS2 reliably separated these taxa, further supporting the use of multiple markers in taxonomic studies and the utility of ITS2 in weevil species delineation.

Information

Type
Research Paper
Copyright
© The Author(s), 2023. Published by Cambridge University Press on behalf of The Entomological Society of Canada
Figure 0

Fig. 1. Neighbour-joining tree (CO1) for Ellescus species under a Jukes–Cantor substitution model (10 000 bootstrap replicates, support threshold of 70%). Note that Ellescus ephippiatus and Ellescus michaelinew species do not separate when CO1 is used but do separate when the faster-evolving marker ITS2 is used (see Fig. 2).

Figure 1

Fig. 2. Neighbour-joining tree (ITS2) for Ellescus species under a Jukes–Cantor substitution model (10 000 bootstrap replicates, support threshold of 70%).

Figure 2

Fig. 3. Morphological characters used to distinguish Ellescus in North America: A, glabrous carina extending longitudinally across last ventrite (male E. bipunctatus); B, swelling at the tip of last ventrite (male E. californicus, E. ephippiatus, and E. michaelinew species); C, metaventrite and metepisternum with dense, heavily appressed scales covering cuticle (found only in both sexes of E. scanicus); and D, metaventrite and metepisternum without dense, heavily appressed scales (Ellescus species other than E. scanicus).

Figure 3

Fig. 4. Ellescus bipunctatus (Linnaeus, 1758): A, lateral view of “scanicus” form; B, dorsal view of “scanicus” form, with alternating bands of white scales and strong band along elytral suture; C, lateral view of red and black specimen; D, dorsal view of red and black specimen; E, lateral view of dark specimen; and F, dorsal view of dark specimen.

Figure 4

Fig. 5. Aedeagi of Ellescus species: A, Ellescus scanicus; B, Ellescus bipunctatus; C, Ellescus californicus; D, Ellescus michaelinew species; and E, Ellescus ephippiatus.

Figure 5

Fig. 6. Spermatheca of Ellescus species: A, Ellescus scanicus; B, Ellescus bipunctatus; and C, Ellescus californicus. Note that E. ephippiatus and E. michaelinew species are not presented because the spermatheca of these species do not differ noticeably from that of E. californicus.

Figure 6

Fig. 7. Ellescus californicus (Casey, 1885): A, dorsal view and B, lateral view.

Figure 7

Fig. 8. Ellescus michaelinew species: A, dorsal view of typical specimen; B, lateral view of typical specimen; C, dorsal view of all-red specimen from Otter Tail Co., Minnesota, United States of America; and D, lateral view of all-red specimen from Otter Tail Co., Minnesota.

Figure 8

Fig. 9. Ellescus ephippiatus (Say, 1832): A, dorsal view of red specimen with conspicuous pattern of scales on elytra; B, lateral view of red, patterned specimen; C, dorsal view of piceous, dark specimen; D, lateral view of piceous, dark specimen; E, dorsal view of red and black specimen lacking conspicuous pattern on elytra; and F, lateral view of red and black specimen.

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