Anthrenus (Anthrenus) semipallens, Holloway & Herrmann, 2023

Holloway, Graham J. & Herrmann, Andreas, 2023, Anthrenus (s. str.) semipallens sp. nov., a new species from Spain (Coleoptera: Dermestidae: Anthreninae), Zootaxa 5323 (1), pp. 126-132 : 127-131

Anthrenus (Anthrenus) semipallens sp. nov. ( Figures 1–2 )

Specimen examined. New record (holotype) for Anthrenus (s. str.) semipallens sp. nov. Spain, Salamanca, Villarejo (N 40.472, E -6.457), 4 th July 2017 J. Marmaneu and E. Micó leg. Holotype ♁ AHEC . Paratypes: Spain, Salamanca , Escurial de la Sierra (N 40.618, E -5.95) 4 th July 2017 J. Marmaneu and E. Micó leg. (one male NHML); Spain, Salamanca, Morillo (N 40.972, E -5.663) 4 th July 2017 J. Marmaneu and E. Micó leg. (one male AHEC); Spain, Salamanca, (N 40.970, E -5.668) 5 th July 2017 J. Marmaneu and E. Micó leg. (one female AHEC) .

External characteristics. Holotype habitus dorsal aspect Figure 1A (BL = 2.5 mm, BW = 1.75 mm). Integument head and pronotum black, margin of pronotum tinged red, basal 1/6 th of elytra black, rest of elytra red. Sharp demarcation between black and red integument of elytra. Elytra loosely covered with white and yellow to pale orange scales, many of which appear to be rectangular and square-ended ( Figure 1B ). Scales not arranged in any particular patterns with no obvious spots or fasciae. Scutellum small and black. Ventrites ( Figure 1C ) covered in offwhite, slightly translucent, loosely packed scales. Scales along outer margins of sternites III, IV, and V more densely packed, have a hint of yellow in them, and increase in density towards the tip of sternite V. Single brown ocellus between eyes. Head entirely covered in black scales. Eyes emarginated on inner margin. Femora, tibiae, and tarsi entirely red with a few whitish scales on the femora. 11-segmented antenna ( Figure 2A ) red throughout. Last three antennomeres forming a well-defined, slightly asymmetric, tear-drop shaped club that expands from antennomere 9 to antennomere 11. Broad sutures separating antennomeres 9 to 11.

Internal characteristics. Aedeagus ( Figure 2B ) has two broad, symmetrical parameres diverging from base before curving evenly inwards ending in blunt tips. Dorsal (concave) surface of each paramere carry inward pointing hairs. Base of median lobe broad, margins converge but are slightly sinuous, ending in a very thin finger-like projection. Sternite IX ( Figure 2C ) has a broad, slightly convex posterior tip carrying stout setae concentrated at outer corners. Strong setae continue down the outer margins beyond the narrowest part of the well-defined neck.

Etymology. The name semipallens translates from Latin as ‘almost pale’ referring to the pale appearance of the new species.

Differential diagnosis. The only Anthrenus s. str. species from Spain ( Holloway et al. 2019) that marginally resembles A. semipallens externally are examples of very pale A. isabellinus Küster, 1848 ( Figure 3 ), although A. isabellinus is generally much larger and rounder than A. semipallens . There are species in different subgenera that generally resemble A. semipallens , including A. (Anthrenodes) bellulus Kocher, 1955 and A. (Helocerus) minutus Erichson, 1846 . Careful inspection of the number of antennal segments and the absence of a notch on the inner margin of the eye will quickly eliminate these species as candidates.

There are Anthrenus species that display colour variation, either fairly discrete variants as in A. delicatus Kiesenwetter, 1851 ( Herrmann 2023) or continuous colour pattern plasticity as in A. isabellinus (Holloway et al. 2022) . Is it possible that A. semipallens is a colour variant of another species? Anthrenus semipallens is small. The male paratypes measure BL 2.75 mm x BW 1.9 mm and BL 2.5 mm x BW 1.8 mm, and the female paratype BL 2.6 mm x BW 1.85 mm, average BL 2.59 mm x BW 1.82 mm, BW/BL = 0.703. These dimensions eliminate A. goliath Mulsant & Rey, 1868 ( Herrmann 2023) and A. flavipes LeConte, 1854 ( Armstrong et al. 2023) since they tend to be larger. Anthrenus pimpinellae (Fabricius, 1775) , A. amandae Holloway, 2019 (Holloway and Bakaloudis 2020) and A. scrophulariae (Linnaeus 1758) (Holloway unpublished data) have BW/BL less than 0.703. Anthrenus angustefasciatus Ganglbauer, 1904 has BW/BL greater than 0.703 ( Holloway and Herrmann 2023). The dimensions of A. chikatunovi Holloway, 2020 (Holloway 2020) , A. delicatus (Holloway unpublished data), A. festivus Erichson, 1846 (Holloway 2023) , and A. munroi Hinton, 1943 ( Holloway and Cañada Luna 2022) correspond to A. semipallens both in terms of BL and BW/BL. Finally, A. miniopictus Bedel, 1884 is recorded as having BL = 2.5 mm ( Herrmann 2023). Anthrenus chikatunovi , A. delicatus , A. festivus , A. miniopictus , and A. munroi all need to be considered as potential confusion species. In addition, A. isabellinus is included courtesy of superficial external resemblance. Figure 4 shows the aedeagi of these six species. None of them resemble the aedeagus shown in Figure 2B A . semipallens is a valid species.

Given these results, Table 1 shows a key to the Anthrenus s. str. in Spain according to Holloway et al. (2019)

(2019).

Figures

FIGURE 1. Anthrenus semipallens sp. nov. Holotype. A: habitus dorsal aspect, B: elytral scales, C: ventrites. Scale bars = 1 mm.

FIGURE 2. Anthrenus semipallens sp. nov. Holotype. A: Antenna, B: aedeagus ventral aspect, C: sternite IX. Scale bars = 100 µm.

FIGURE 3. Anthrenus isabellinus pale example. Scale bar = 1 mm.

FIGURE 4. Aedeagi. A: Anthrenus chikatunovi, B: Anthrenus delicatus, C: Anthrenus festivus, D: Anthrenus isabellinus. E: Anthrenus miniopictus, F: Anthrenus munroi. Scale bars = 100 µm.