Galerucella (Neogalerucella) anserina Ødegaard & Hanssen, 2020

Ødegaard, Frode & Hanssen, Oddvar, 2020, Galerucella (Neogalerucella) anserina Ødegaard & Hanssen, sp. nov., a new species of Chrysomelidae (Coleoptera, Chrysomelidae, Galerucinae) from Norway, Zootaxa 4755 (2), pp. 341-352 : 342-346

Galerucella (Neogalerucella) anserina Ødegaard & Hanssen , sp. nov.

Holotype ♂: Norway, VESTFOLD [VE], Faerder municipality, Ørahavna [EIS 19, E 10.43476° – N 59.09440°], 6 June 2013, leg. Oddvar Hanssen ( NINA ).

Paratypes 44 ♂♂ and 45 ♀♀: Norway, VESTFOLD [VE], Faerder municipality, Ørahavna [EIS 19, E 10. 43476° – N 59.09440°], pitfall trap 13 June–5 July 2012, 1 ♀; 6 June 2013, 13 ♂♂ and 7 ♀♀; 11 June 2014, 9 ♂♂ and 10 ♀♀, leg. Oddvar Hanssen; Norway, VESTFOLD [VE], Faerder municipality, Holme [EIS 19, E 10.43334° – N 59.11035°], 6 June 2013, 2 ♂♂ and 7 ♀♀; 11 June 2014, 3 ♂♂ and 8 ♀♀, leg. Oddvar Hanssen; 18 June 2015, 4 ♂♂, leg. Frode Ødegaard; Norway, VESTFOLD [VE], Faerder municipality, Barkevika [EIS 19, E 10.38744° – N 59.10428°], 11 June 2014, 1 ♂, leg. Oddvar Hanssen; Norway, VESTFOLD [VE], Faerder municipality, Taredyn- gerevet [EIS 19, E 10.39268° – N 59.06863°], 5 June 2013, 2 ♀♀; 11 June 2014, 1 ♂, leg. Oddvar Hanssen; Norway, VESTFOLD [VE], Sandefjord municipality, Bøkilen [EIS 19, E 10.27329° – N 59.11714°], pitfall trap 12 June–5 July 2012, 1 ♂, leg. Oddvar Hanssen; Norway, AUST-AGDER [AAY], Grimstad municipality, Saulekilen [EIS 19, E 8.51105° – N 58.29232°], 4 June 2013, 1 ♂; 12 June 2014, 3 ♂♂ and 4 ♀♀, leg. Oddvar Hanssen; Norway, ØST- FOLD [Ø], Hvaler municipality, Landfastodden [EIS 20, E 10.93273° – N 59.04639°], 9 May 2016 1 ♂, leg. Frode Ødegaard; Norway, ØSTFOLD [Ø], Hvaler municipality, Vikerkilen [EIS 20, E 10.94004° – N 59.04619°], 9 May

2016, 1 ♂ and 1 ♀, leg. Frode Ødegaard; Norway, ØSTFOLD [Ø], Fredrikstad municipality, Gonvad, [EIS 20, E 10.91653° – N 59.16834°], 7 June 2013, 1 ♂; 9 June 2014, 1 ♂ and 1 ♀; 27 June 2015, 1 ♂ and 4 ♀♀, 8 May 2016, 1 ♂, leg. Frode Ødegaard.

Description: Body length: 3.2–4.2 mm (linear distance from labrum to elytral apex); width: 1.37–1.62 mm (width across base of elytra) ( Figure 1 ). Males are often smaller than females. Coloration: Head brown, with large black spot on vertex that sometimes reach upper eye margin; pronotum brown, sometimes with diffuse darker spot in middle; scutellum black; elytra brown, often with diffuse darker spots on shoulders (humeral calli). Central area of each elytron often darker; venter: mesosoma black, except for pronotum; abdomen black, except for sternite 5 brown; legs pale brown; antennae brownish black, except for ventrally pale first four antennomeres. Mandibles pale brown with black apex; other mouthparts pale brown; palpomeres dark brown. Dorsum covered with dense, thick, white pubescence. Venter covered with white pubescence less dense near midline.

Head: Narrower than pronotum, densely and coarsely punctate, interstices with irregular microreticulation; with median depressed line from middle of vertex to below antennal sockets. Antennae 1.81–2.26 mm long; length ratio of antennomeres 1 to 11 (antennomere 2 set as length 1): 2-1-1.33-1.13-1.06-1-1-1-1-1-1.53.

Pronotum: Length 0.52–0.70 mm; width 1.03–1.22 mm. Wide depression on each side of disk. Smaller depressions along midline and at each side in front of posterior margin; pronotal disk margined all around. In dorsal view anterior 1/3 of lateral margins not visible. Lateral margin sinuate and pointed posterolaterally. Punctation and microreticulation as on head, except for more elevated areas behind anterior margin, and at each side of middle depression before posterior margin, which are more scattered punctured with interstices larger than point diameter ( Figure 8a ).

Elytra: Length 2.11–2.86 mm; widest at apical 4/5, then broadly rounded to apex. In dorsal view elytral margin bent broadly upwards to apex. Punctation irregular, coarse and distinct. Interstices narrower than puncture diameter, rather shiny with fine irregular microreticulation. Epipleuron broad basally and gradually narrowed towards apex, but still at breadth of middle part of metatibiae, at site where it fades towards apex. Hind wings fully developed.

Ventral surface: Mesosternum and metasternum smooth with fine punctation. Mesepisternum and mesepimeron with white pubescence. Abdomen with fine punctation; sternites 2–4 similar in length ( Figure 1b ). In males last sternite (St. 5) with more or less V-shaped cavity anterad of the posterior edge. Posterior margin with shallower and broader emargination in the middle ( Figure 2 ). In females posterior margin of last sternite with variably deep and narrow emargination on midline ( Figure 3 ). Legs: Mesotibiae of males with short spine bent outwards, like in other Neogalerucella .

Aedeagus: In dorsal view aedeagus parallel and slightly asymmetrical near the blunt tip ( Figure 5a ). Complex internal structures and Y-shaped sclerite of internal sac ( Figure 6a ). In lateral view, aedeagus broad, parallel and weakly curved in apical 2/3; apex blunt ( Figure 7a ). Spermatheca with short ductus with few windings, and a Ushaped capsule with subparallel head ( Figure 3 ).

Comparative notes: Galerucella anserina matches diagnostic characteristics of the G. tenella -group of Galerucella (Neogalerucella) based on narrowly separated middle coxae, front coxae not separated by a prosternal process, the broad shape of epipleura, and the Y-shaped sclerite of the internal sac of the aedeagus ( Silfverberg 1974, Arnett et al. 2002). The new species can be distinguished from the American species G. quebecensis and G. stefanssoni , by the black colored sternite 4, dark markings on elytra, and different shape of aedeagus ( Manguin et al. 1993). The eastern Palaearctic species differ in several characters and particularly the shape of aedeagus ( Beenen 2008, Nie et al. 2013). In European literature ( Hansen 1927, Palmén 1945, Mohr 1966, Warchalowski 2010), the species will key out together with G. tenella , from which the males can be distinguished by the broad and parallel shaped aedeagus with a blunt tip seen in lateral view ( Figure 7 ), and a more asymmetrical and blunt tip seen in dorsal view ( Figure 5 ). The females of G. anserina have a more or less U-shaped emargination of the last sternite compared with G. tenella . The depth of this emargination covers more than 1/10 of the sternite length ( Figure 3 ), compared with less than 1/20 of the sternite length in G. tenella ( Figure 4 ). The spermatheca of the two species are variable and very similar, but in G. anserina ( Figure 3 ) the spermatheca capsule has a deeper U-shaped neck, and a longer and more parallel head, than in G. tenella ( Figure 4 ). In G. anserina the antennae are often darker than in G. tenella , with dark pattern also on the dorsal side of the first segments, the 3rd segment is 1.15–1.25 times longer than the 4th. In G. tenella the first segments are pale brown and the 3rd antennal segment is 1.30–1.40 times longer than the 4th. The dorsum has more evident and dense, pale pubescence than any other species in the group ( Figure 9 ). The depressed areas of pronotum are larger and deeper than in G. tenella . The sides of the pronotum of G. anserina are dense and irregularly punctate, and the elevated areas are less shiny than in G. tenella due to more evident microreticulation ( Figure 8 ). The coloration of the antennae, the shape of the last sternite and the pronotal punctures are characters shared with G. calmariensis and G. pusilla . However, G. anserina has a broader body shape, as in G. tenella , and the antennae are very rarely as dark as in these species. The dense, white pubescence of the dorsum and the shape of aedeagus are otherwise unique characters of G. anserina .

DNA-barcoding: DNA-barcoding was successful and gave sequences of 658 bp for all specimens. All analyzed sequences were 100 % similar, and BIN-clustered together with G. tenella (48 individuals) from other parts of Europe (BOLD:ACF3471). The nearest BIN-clade (BOLD:AAL2945), average distance 0.21 %, includes European G. calmariensis , G. pusilla and undetermined Neogalerucella from North-America (79 individuals).

Etymology: The specific epithet (adjective) is derived from the host plant Potentilla anserina .

Distribution and bionomics: The new species was recorded at eight different coastal sites in the outer Oslofjord-area in the southeast of Norway, as well as one isolated site along the southern coast of Norway ( Figure 10 and 11 ). At four of these sites G. anserina and G. tenella were found sympatrically. During an extensive search on potential host plants within Rosaceae at the sample sites, all specimens of G. anserina were found on Potentilla anserina , whereas G. tenella where found exclusively on Filipendula ulmaria . However, along the western coast of Norway, G. tenella was also found feeding on Potentilla anserina (pers. obs., F. Ødegaard 2019), confirming that G. tenella is an oligophagous species reported feeding on several species of Rosaceae ( Rheinheimer & Hassler 2018) . However, we expect that G. anserina has a wider distribution outside Norway that is to be revealed by revisions of collections and specific searching on the host plants.

Figures

FIGURE 1. Habitus, a) dorsal view of Galerucella anserina, holotype, male; b) ventral view, G. anserina, male. Photo: Arnstein Staverløkk/NINA.

FIGURE 2. Last sternite of Galerucella anserina, male. Photo: Arnstein Staverløkk/NINA.

FIGURE 3. Last sternite and spermatheca from two female paratypes of Galerucella anserina. Photo: Arnstein Staverløkk/ NINA.

FIGURE 4. Last sternite and spermatheca of two different females of Galerucella tenella. Photo:Arnstein Staverløkk/NINA.

FIGURE 5. Aedeagus dorsal view a) Galerucella anserina and b) G. tenella. Photo: Arnstein Staverløkk/NINA.

FIGURE 6. Aedeagus ventral view a) Galerucella anserina and b) G. tenella. Photo: Oddvar Hanssen.

FIGURE 7. Aedeagus lateral view of a) Galerucella anserina and b) G. tenella. Photo: Arnstein Staverløkk/NINA.

FIGURE 8. Head and pronotum of a) Galerucella anserina and b) G. tenella. Photo: Arnstein Staverløkk/NINA.

FIGURE 9. Section of the elytral disk in central anterior area of left elytra of a) Galerucella anserina and b) G. tenella. Photo: Arnstein Staverløkk/NINA.

FIGURE 10. Four localities in Norway where Galerucella anserina has been found: a) Ørahavna, Faerder municipality, Vestfold county. Photo: Oddvar Hanssen; b) Holme, Faerder municipality, Vestfold county. Photo: Oddvar Hanssen; c) Saulekilen, Grimstad municipality, Aust-Agder county. Photo: Oddvar Hanssen; d) Gonvad, Fredrikstad municipality in Østfold county. Photo: Frode Ødegaard.

FIGURE 11. The geographical distribution of the known collection sites of Galerucella anserina in southern Norway.