Anomognathus cuspidatus (Erichson, 1839)
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
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|Anomognathus cuspidatus (Erichson, 1839)|
Homalota cuspidata Erichson, 1839
Thectura americana Casey, 1893, syn. nov.
Anomognathus americanus : Seevers (1978) (as valid species)
Homolota cuspidata Erichson, 1839. Lectotype, male, here designated ( ZMHB): Homolota cuspidata Er: [handwritten label] / 5387 [typed label] / Hist.-Coll. ( Coleoptera ), Nr. 5387, Homalota cuspidata , Erichs., Europa, Zool. Mus. Berlin [typed white label] / Lectotype Homalota cuspidata des. J. Klimaszewski 2019 [white printed label]. Paralectotypes (3, ZMHB, without original labels): Hist.-Coll., ( Coleoptera ), Nr. 5387, Homolota cuspidata Erichs., Europa, Zool. Mus. Berlin; Syntype Homolota cuspidata Erichson, 1837, labelled by MNHUB 2010; Paralectotype Homalota cuspidata des. J. Klimaszewski 2019 [white printed label] [1 female, spermatheca and terminalia dissected in Canada balsam on microslide attached to specimen]; same labels except: SYNTYPUS, Homalota cuspidata Erichson, 1837 [typed red label, added by MNHUB 2010] [1 female, spermatheca and terminalia dissected in Canada balsam on microslide attached to specimen]; same labels as before [1 damaged specimen, sex undetermined].
Males and females of the syntype series were morphologically consistent with the specimens forming molecular cluster BOLD:AAO0339, including those sequenced from Ontario, Canada. As the most obvious difference between A. cuspidatus and the potential new Central European species (see Diagnosis) was the shape of the median process on male tergite VIII (in lateral view) (Fig. 18B, D View Figure 18 ), a male syntype (see above) was designated as the lectotype of this species to fix its identity. Morphology of the aedeagus itself was difficult to study due to its small size and obvious differences between molecular clusters (see below) were not observed (Fig. 19 View Figure 19 ).
Casey (1893) gave numerous characters to distinguish A. americanus from A. cuspidatus but all of these were observed to be highly variable within populations in the material studied, including the shape of apical antennomeres, shape of the pronotum, position of the abdominal tubercles in the male, and the type of dorsal expansion of the median process of male tergite VIII. We could not find the depression at the base of tergite VIII on the holotype of A. americanus mentioned by Casey (1893). Although the aedeagus of the holotype was not studied (not extracted from partly damaged and fragile pygidium), male tergite VIII was intact and its median process in lateral view bears an apical hook, matching the present concept for A. cuspidatus (Fig. 20 View Figure 20 ). Therefore, in corroboration with Fenyes (1918), we treat A. americanus as a synonym of A. cuspidatus .
(sequenced specimens indicated in square brackets). Canada: Alberta: Peace River, 25 km NW Peace River, 17-23.VIII.1993, J. Hammond (2, CNC); Ontario: Wellington County, Guelph, Eramosa River Trail, 43.539, -80.236, deciduous forest, 14.IV.2017, M. Pentinsaari (4, CBG [4 barcoded]).
A photo record of this species from Ontario is available on bugguide.net (/view/1816108): Toronto, 19.V.2020, under bark, O. Strickland.
Belgium: Sint-Genesius-Rode, BR Zonienwoud, 50.7505, 4.423, 28.IV.2010, F. Koehler (1, ZSM [1 sequenced]). Czech Republic (all CNC): Bohemia, Poděbrady 50 km, Smetana, 1959, car net trap (1); Bohemia, Chvojno, Smetana (1); Moravia, Drnholec, Smetana (1). Denmark (all NHMD): Staksrode, EJ, 24.IX.1983 (1); Æbelø F, 18.V.1997 (1); Faested Mose, SJ, 12.IV.1986 (1); Dyrehaven, 14.4.1934 (1); same except 21.3.1923 (1); same except 21.10.1932 (1); 30.4.1922 (1); same except 19.5.1911 (1); Lyng Huse, 29.3.1997 (1).
Germany: Nationalpark Mueritz, Babke-Zartwitz-Speck-Schwarzenhof, 53.4125, 12.8463, car net, 20.VI.2015, GBOL-Team ZFMK (2, ZFMK [2 sequenced]); Hoenningen bis Insul, Ahrtal, 50.45, 6.942, 24.IV.2010, F. Koehler (1, ZSM [1 sequenced]); Oberheimbach, Franzosenkopf, 50.004, 7.805, 27.V.2012, W. Koehler (1, ZSM [1 sequenced]). Finland (all ZMUO): N: Espoo, Saunalahti, 60.1643, 24.6263, 17.IX.2012, fungusy aspen logs, E. Helve (1) [barcoded]; Al: Bjoerkoe, 59.9769, 20.1879, sifting, 24.IX.2014, M. Pentinsaari (1) [barcoded]; Ta: Lammi, R. Linnavuori leg. (1); Ab: Naantali, R. Linnavuori leg. (1); Kb: Lieksa, R. Linnavuori (1); Rynmattyla, 24.VI.1945, Karvonen (2); same except 14.VIII.1945 (2). Slovakia (all CNC): Cenkov, Smetana, 1963 (11); Nová Sedlica, Smetana, 1961 (2); Ruská Poruba, Smetana, 1956 (2). United Kingdom (all CNC): Essex (6).
Putative undescribed Anomognathus (corresponding to BIN BOLD:ACA9191):
Finland (all ZMUO): N: Espoo, E. Helve, 1978 (1); same except 1976 (1); same except 1977 (1); same except 1979 (1); same except 1981 (1); same except 1982 (1); Ks: Taivalkoski, 728.53 Window trap, 2003, E. Hurme (2); same except Polyporus trap (1); Kb, Kitee, 23.05.2016, M. Pentinsaari leg., [1 sequenced]; Obb: Rovaniemi, Rovajärvi, 16.6-8.7.2010, M. Pentinsaari and E. Kuusela [1 sequenced]. Germany: Schleiden-Wolfgarten, Dachsloecher, 50.6098, 6.42237, 26.VII.2012, F. Koehler (1, ZSM [1 sequenced]).
Anomognathus cuspidatus is distinctive for its trident-shaped apex of male and female tergite VIII (Fig. 20A-C View Figure 20 ) and can be distinguished from all described species by this feature alone. However, in the course of this study, specimens representing a remarkably divergent barcode cluster (BOLD:ACA9191; 9.63% uncorrected p-distance to A. cuspidatus ) were investigated and found to likely represent an undescribed species of Anomognathus in Europe (confirmed specimens from Finland and Germany). Although most morphological characters of A. cuspidatus and the putative new species are highly variable, including the median lobe of the aedeagus, males can be dependably separated based on the shape of their median process of tergite VIII in lateral view: A. cuspidatus bears a minute to distinct hook at the apex (Fig. 20A-C View Figure 20 ), while in the undescribed species, the median process converges evenly to a single point, creating an elongate, turnip-shape (Fig. 20D View Figure 20 ). The shape of tergite VIII in females was observed to be extremely variable and no features were deemed to be diagnostic. Externally, most specimens can be recognized as either species (especially males) by the relative proportions of the head versus the pronotum, with A. cuspidatus generally bearing a small pronotum, narrower than the head (Fig. 18A View Figure 18 ) and the undescribed species bearing a wider, longer pronotum, wider than the head (Fig. 18C View Figure 18 ). The limits of this taxon need further investigation and should include morphological study of a much wider range of sequenced material.
Origin: West Palaearctic (adventive in North America). Canada: AB, NB, ON. United States: NY.
This species occurs under the bark of dead trees. One specimen (NB) was collected from a Lindgren funnel.
Anomognathus cuspidatus is a widespread West Palaearctic species that is known from Europe, European Russia and Algeria ( Newton 2019) and has been previously known in North America under the synonym A. americanus . The record from Beijing, China should be verified. The species has become introduced in North America (before 1893) and it is unclear whether the population in Alberta represents a separate introduction from Europe, a secondary introduction from eastern North America or a broad adventive distribution across Canada.
After the results of the present study, two species of Anomognathus are known to occur in North America: native A. athabascensis Klimaszewski, Hammond & Langor and the adventive A. cuspidatus . These are easily separated by the drastically different shapes of male and female tergites VIII (Figs 17D View Figure 17 , 20A-C View Figure 20 ). Previously, only females of A. cuspidatus (as A. americanus ) were available from Canada ( Klimaszewski et al. 2016b; Webster et al. 2016). Here we demonstrate that all available Nearctic Anomognathus specimens with a trident-shaped tergite VIII correspond to Palaearctic A. cuspidatus .
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