Paradilacra densissima (Bernhauer, 1909)

Brunke, Adam J., Pentinsaari, Mikko & Klimaszewski, Jan, 2021, Integrative taxonomy of Nearctic and Palaearctic Aleocharinae: new species, synonymies, and records (Coleoptera, Staphylinidae), ZooKeys 1041, pp. 27-99 : 27

Paradilacra densissima (Bernhauer, 1909) Fig. 7A-H

Atheta (Paradilacra) densissima Bernhauer, 1909

Gnypeta saccharina Klimaszewski & Webster, 2008, syn. nov.

Material

(DNA barcoded specimens). Canada: Alberta: Waterton Lakes National Park, Highway 6 pulloff, 49.065, -113.779, 1569 m, intercept trap, montane forest, 27.VI.2012, BIOBus 2012 (1, CBG) ; British Columbia: 10 km W Kamloops, New Afton Mine, Wetland Protected Area , 50.662, -120.504, 702 m, malaise trap, 22.VIII.2013, C. Simon (1, CBG) ; New Brunswick: York Co., Fredericton at Saint John River , 45.959, -66.625, margin of river in flood debris, 7.VII.2005, R.P. Webster [note: paratype of G. saccharina ] (1, LFC) ; Ontario: Guelph, University of Guelph Arboretum , 43.53, -80.21, 12.VI.2019, M. Pentinsaari (1, CBG) .

Distribution.

Origin: Nearctic. Canada: AB, BC, NB, ON [new record], SK [new record]. United States: CA, MT, NV, ND, OR, UT.

Bionomics.

This species has been collected from various wetland microhabitats including the edges of lakes, rivers, and a beaver pond ( Gusarov 2003a).

Comments.

Paradilacra densissima and the genus Paradilacra , widespread in western and central North America ( Gusarov 2003a), are newly reported from SK (records in Klimaszewski et al. 2016a, as G. saccharina ) and eastern North America based on records from NB ( Klimaszewski et al. 2008) and ON (this study), including one sequenced paratype of synonym Gnypeta saccharina . Under the present concept, only one widespread species of this genus is known.

Dasygnypeta Lohse, 1974, sensu nov.

In his key to the genera of Tachyusini , Paśnik (2010) distinguished Dasygnypeta , with its single Palaearctic species Dasygnypeta velata (Erichson), from the Nearctic genera by the following features: the narrow and slender abdomen with base approximately as wide as head, the 'very deep’ tergal impressions, abdominal pubescence of tergites III-V directed posteriad, basal segment of metatarsus shorter than following two segments. Through an analysis of barcode data, we have discovered that the recently described Gnypeta minuta Klimaszewski & Webster is a synonym of D. velata (see below). A re-examination of other Nearctic Gnypeta species revealed two others that are closely related to D. velata : G. baranowskii Klimaszewski, and G. nigrella (LeConte). Their morphological divergence from other Gnypeta was represented by an earlier placement in the 'Nigrella species group’ of Gnypeta by Klimaszewski et al. (2008), together with G. saccharina (now a synonym of Paradilacra densissima ). In corroboration with morphology, DNA barcodes of D. velata and G. nigrella form sister clusters (sequences of G. baranowskii not available). Transfer of these two Gnypeta species to Dasygnypeta required a new concept for this genus as most of the distinguishing features were apomorphies of D. velata or found not to be of diagnostic value due to variability or overlap with other genera. Here we distinguish members of Dasygnypeta by their characteristic abdomen (Figs 10 - 12 ): base of abdomen ca. as wide as head; basal half of abdomen elongate, tergite III (first visible) only moderately transverse, ~ 2 × as wide as long (at least 2.5 × in Gnypeta ); tergites III-V with very deep basal impressions, each creating strongly convex areas on the disc. Members of Dasygnypeta could be confused with Tachyusa , which also bears an elongate basal abdomen, but in the latter genus tergites III-V are far more elongate and the abdominal base is narrower than the head (Fig. 9 ). Dasygnypeta nigrella was even originally described by LeConte (1863) in Tachyusa , likely based on this similarity.

Figures

Figure 7. Paradilacra densissima (Bernhauer) A habitus B median lobe of aedeagus in lateral view C median lobe of aedeagus in dorsal view D spermatheca E male tergite VIII F male sternite VIII G female tergite VIII H female sternite VIII. Scale bars: 1 mm (A); 0.2 mm (B-H). Illustrations after Klimaszewski et al. (2018), used with permission.

Figure 9. Tachyusa obsoleta Casey A habitus B median lobe of aedeagus in lateral view C median lobe of aedeagus in dorsal view (adapted from Pasnik 2006) D spermatheca E male tergite VIII F male sternite VIII G female tergite VIII H female sternite VIII. Scale bars: 1 mm (A); 0.2 mm (B-H). Illustrations after Klimaszewski et al. (2018), used with permission.

Figure 10. Dasygnypeta baranowskii (Klimaszewski) A habitus B median lobe of aedeagus in lateral view C median lobe of aedeagus in dorsal view D spermatheca E male tergite VIII F male sternite VIII G female tergite VIII H female sternite VIII. Scale bars: 1 mm (A); 0.2 mm (B-H). Illustrations after Klimaszewski et al. (2020), used with permission.

Figure 12. Dasygnypeta velata (Erichson) A habitus B median lobe of aedeagus in lateral view C median lobe of aedeagus in dorsal view D spermatheca E male tergite VIII F male sternite VIII G female tergite VIII H female sternite VIII. Scale bars: 1 mm (A); 0.2 mm (B-H). Illustrations after Klimaszewski et al. (2018), used with permission.