Atheta (Dimetrotina) pasadenae (Bernhauer, 1906)

(Figs. 1, 3, 5–6, 10– 11, 17 in Tronquet 2000)

Atheta (Acrotona) pasadenae Bernhauer, 1906: 338 .

Dimetrota (Dimetrotina) vaniuscula Casey, 1911: 144, syn. nov.

Atheta (Acrotona) pasadenae: Bernhauer & Scheerpeltz, 1926: 676 (as valid species).

Atheta (Dimetrota) vaniuscula: Bernhauer & Scheerpeltz, 1926: 665 (as valid species).

Atheta (Acrotona) sp.: Jansson, 1940: 21 (listed as new species (“? nov. sp.”) but unnamed).

Atheta (s. str.) pseudocoriaria Bernhauer, 1943: 175, syn. nov.

Atheta (Acrotona) zealandica Cameron, 1945: 167, syn. nov.

Atheta (Acrotona) sp. prope laticollis (Stephens): Brinck, 1948: 35.

Atheta sp.: Lundblad, 1958: 471 (the same species as in Jansson 1940).

Atheta zealandica: Brinck, 1977: 86 (as valid).

Atheta maderensis: Brinck, 1977: 86 (as synonym of A. zealandica; spelled as A. maderense; misidentification).

Acrotona pasadenae: Seevers, 1978: 256 (as valid).

Dimetrota vaniuscula: Seevers, 1978: 260 (as valid).

Atheta (Xenota) dilutipennis: Muona, 1984: 229 (misidentification).

Atheta (s. str.) aucklandensis Pace, 1987: 436 (replacement name for Atheta pseudocoriaria Bernhauer, 1943, non Cameron, 1939), syn. nov.

Atheta laticollis: Erber & Hinterseher, 1988: 186 (misidentification).

Atheta (s. str.) laticollis: Borges, 1990: 106 (misidentification).

Atheta pseudolaticollis Erber & Hinterseher, 1992: 2 (placed in Mischgruppe I).

Atheta pseudolaticollis: Hernandez et al. 1994: 185 (as valid).

Atheta (Xenota) immucronata Pace, 1999: 151 .

Atheta pseudolaticollis Erber & Hinterseher: Assing, 2000: 118 (as junior primary homonym).

Atheta pseudolaticollis: Machado & Oromí, 2000: 44 (as valid).

Atheta pseudolaticollis: Boieiro et al., 2001: 19, 20 (as valid).

Atheta (s. str.) gulosa Tronquet, 2000: 365 .

Atheta (Xenota) pseudoinsulana Klimaszewski in Klimaszewski et al., 2002: 485, syn. nov.

Atheta atlantidum Smetana, 2004a: 32 (replacement name for Atheta pseudolaticollis Erber & Hinterseher, 1992, non Bernhauer, 1936, non Cameron, 1944).

Atheta (Mycetota) atlantidum: Smetana, 2004b: 389 (as valid).

Atheta (Mycetota) pseudolaticollis: Smetana, 2004b: 389 (as synonym of Atheta atlantidum).

Atheta (Mycetota) immucronata: Smetana, 2004b: 389 (as valid).

Atheta (Mycetota) gulosa: Smetana, 2004b: 389 (as synonym of Atheta immucronata).

Atheta (Xenota) immucronata: Pace, 2006: 412 (as valid).

Atheta (Xenota) pseudoinsulana: Pace, 2006: 412 (as synonym of A. immucronata).

Atheta immucronata: Assing & Schülke, 2006: 106 (as valid).

Atheta pseudolaticollis: Assing & Schülke, 2006: 106 (as synonym of A. immucronata).

Atheta gulosa: Assing & Schülke, 2006: 106 (as synonym of A. immucronata).

Atheta atlantidum: Assing & Schülke, 2006: 106 (as synonym of A. immucronata).

Atheta zealandica: Assing & Schülke, 2006: 112 (as valid).

Atheta maderensis: Assing & Schülke, 2006: 112 (as synonym of Atheta zealandica; misidentification).

Atheta (Mycetota) pasadenae: Elven et al., 2010: 89 (as valid).

Atheta (Mycetota) pasadenae: Elven et al., 2012: 621 (as valid).

Atheta (Mycetota) pasadenae: Schülke & Smetana, 2015: 545 (as valid).

Atheta (Mycetota) atlantidum: Schülke & Smetana, 2015: 545 (as synonym of A. pasadenae).

Atheta (Mycetota) gulosa: Schülke & Smetana, 2015: 545 (as synonym of A. pasadenae).

Atheta (Mycetota) immucronata: Schülke & Smetana, 2015: 545 (as synonym of A. pasadenae).

Atheta (Mycetota) pseudolaticollis: Schülke & Smetana, 2015: 545 (as synonym of A. pasadenae).

Type material. Lectotype of Atheta pasadenae (here designated): ♂ (genitalia examined), “Pasadena, Cal[ifornia].”, “Feb. [18]97”, “ Pasadenae Brh. Typus. lg. Fenyes det. Bernhauer”, “ Pasadenae Bernh. Typus ” (yellow-brown label), “Chicago NHMus M.Bernhauer Collection” (FMNH). Paralectotypes (2) (genitalia examined): ♀, “Pasadena, Cal[ifornia].”, “Jan. [18]97”, “ Pasadenae Bernh. Cotypus” (yellow-brown label), “Chicago NHMus M.Bernhauer Collection”; ♂, “Pasadena, Cal[ifornia].”, “Feb. [18]97”, “ Pasadenae Bernh. Cotypus” (yellow-brown label), “Chicago NHMus M.Bernhauer Collection” (both FMNH).

Holotype of Dimetrota vaniuscula: ♀ (genitalia examined), "Esmeralda Co[unty]. XI.27. [19]07 Nev[ada]", " Dimetrotina vaniuscula Cas [ey]", " CASEY bequest 1925", " TYPE USNM 39130" (red label) (NMNH).

Lectotype of Atheta pseudocoriaria (here designated; the designation is to be attributed to Richard A.B. Leschen, as Leschen in Gusarov 2015): ♂ (genitalia examined), “ Type ” (circular label with red margin), “A”, “Dry rot swede [a plant] Mr Gibbs M.C. area Palm[erston]. N[or]th N[ew]. Z[ealand]. W.Cottier 25/6/[19]31”, “Pres[ented]. By Imp[erial]. Inst[itute of]. Ent[omology]. Brit[ish]. Mus[eum]. 1931-469.”, “ Atheta pseudocoriaria Bernh. Typus ”, “ LECTOTYPE Atheta (Atheta) pseudocoriaria Bernhauer 1943 Design. by R. Leschen, 2014” (red label) (BMNH). Paralectotypes (4): ♀ (genitalia examined) and 3♂, “Cotype” [circular label with yellow margin], “A”, “X Dry-rot swede Mr. Gibbs M.C. area Palm[erston]. N[or]th. N[ew]. Z[ealand]. W.Cottier. 25/6/[19]31”, “Pres[ented]. By Imp[erial]. Inst[itute of]. Ent[omology]. Brit[ish]. Mus[eum]. 1931-469.”, “ PARALECTOTYPE Atheta (Atheta) pseudocoriaria Bernhauer 1943 Design. by R. Leschen, 2014” (blue label) (BMNH) (According to Newton & Thayer (2005), six additional types, now becoming paralectotypes, are deposited in FMNH; not examined).

Lectotype of Atheta zealandica (here designated; the designation is to be attributed to Richard A.B. Leschen, as Leschen in Gusarov 2015): ♂ (genitalia examined), “ Type ” (circular label with red margin), “from dry rot lesions on swede Palmerston North New Zealand W.Cottier Feb.1930 ”, “Brit. Mus. 1946-60 ”, “ Atheta zealandica Cam. TYPE ”, “ LECTOTYPE Atheta (Acrotona) zealandica Cameron 1945 Design. by R. Leschen, 2014” (red label). Paralectotype: ♀ (genitalia examined), “from dry rot lesions on swede Palmerston North New Zealand W.Cottier Feb. 1930 ”, “M. Cameron Bequest B. M. 1955-147”, “ A. zealandica Cam. COTYPE”, “ PARALECTOTYPE Atheta (Acrotona) zealandica Cameron 1945 Design. by R. Leschen, 2014” (blue label) (BMNH).

Additional material. CHILE: Juan Fernandez Archipelago: 2♂, 2♀, Alejandro Selkirk Island (Isla Más Afuera), Quebrada de las Vacas, 20.i.1955 (P.G.Kuschel); 2♀, Alejandro Selkirk Island (Isla Más Afuera), Quebrada de las Casas, in rotting stem of Gunnera masafuerae near water, 19.i.1952 (P.G.Kuschel) (all the Juan Fernandez specimens bear the manuscript name label Atheta juanfernandezica Scheerpeltz) (all BMNH); FRANCE: Pyrénées-Orientales: 16 specimens, Mosset–col de Jau, 1450 m, 19.viii.2007 (M. Tronquet) (ZMUN); NEW ZEALAND: Auckland: 4♂, Auckland (carrying label “Sharp Coll. 1905-313”); ♂, Auckland; ♂, ♀, Auckland, Lynfield, Tropicana Dr., on fruit, 10.vii.1974 (G.Kuschel); ♂, ♀, ditto but 20.vii.1974 (all BMNH); Manawatu-Wanganui: 4♂, 2♀, Palmerston North, from dry rot lesions on swede, ii.1930 (W.Cottier); 2♂, 2♀, ditto but 28.ii.1930; ♀, ditto but 20.iii.1930; ♀, ditto but 25.iii.1930 (all BMNH); No locality data: ♂, ♀ (BMNH); U.K.: Tristan da Cunha archipelago: Tristan da Cunha island: 5♂, 5♀, west of settlement, James Glass’ patches, 37°09’06”S 12°34’26”W, 40 m, cultivated cropland, potatoes, “weeds”, sedges, mosses, etc., 7.ii.2005 (C.Hänel); ♀, west of Edinburgh village, 37°09’06”S 12°34’26”W, 40 m, potato patches, cultivated cropland, potatoes, vegetable gardens and cattle grazing, 7.ii.2005 (C.Hänel); Nightingale island: ♂, west landing area, 37°24’98”S 12°28’69”W, coastal cliffs, cave overhang with tussock, path up from landing, Malaise trap, 3– 4.iv.2005 (C.Hänel) (all ZMUN).

Diagnosis. Atheta pasadenae can be recognized by the following combination of characters: pronotal hypomera invisible in lateral view, pronotal setation along midline directed anteriad, posterior margin of male tergite 8 quadri-dentate with median emargination wider than the two lateral emarginations (Fig. 3 in Tronquet 2000), spermatheca with distal part of distinct shape (Figs. 5–6 in Tronquet 2000), internal sac of the aedeagus with a pair of C-shaped lateral sclerites (Figs. 10–11 in Tronquet 2000), antennomeres 5–10 transverse.

Discussion of synonymies. The holotype of D. vaniuscula is identical with the types of A. pasadenae in external characters and the distinct shape of spermatheca. Therefore the first name is placed in synonymy with the second (older) name.

The examined types of A. pseudocoriaria are identical to the types of A. pasadenae in external characters, including the male secondary characters, and the shape of spermatheca and aedeagus, including the distinct sclerites of the internal sac. For this reason, A. pseudocoriaria and its objective synonym (replacement name) A. aucklandensis are considered synonyms of A. pasadenae . An additional paralectotype of A. pseudocoriaria deposited in BMNH and not listed above in Type material represents another athetine species, with much smaller pronotum, well visible pronotal hypomera and different pronotal setation pattern. The specimen is labeled “Cotype” [circular label with yellow margin], “A”, “X Dry-rot swede Mr. Gibbs M.C. area Palm[erston]. N[or]th. N[ew]. Z[ealand]. W.Cottier. 25/6/[19]31”, “Pres[ented]. By Imp[erial]. Inst[itute of]. Ent[omology]. Brit[ish]. Mus[eum]. 1931-469.”, “ PARALECTOTYPE Atheta (Atheta) pseudocoriaria Bernhauer 1943 Design. by R. Leschen, 2014” (blue label) and it is missing the abdomen and most of the antennae. Identification label “not Atheta pasadenae ” was added to this paralectotype specimen.

The examined types of A. zealandica are identical with the types of A. pasadenae in external characters, including the male secondary characters and the shape of spermatheca and aedeagus, including the distinct sclerites of the internal sac. For this reason, A. zealandica is placed in synonymy with A. pasadenae .

The types of Rhagocneme maderense Likovský, 1963 were not examined. Brinck (1977) listed Atheta maderensis (ex Rhagocneme Munster, 1923) as synonym of A. zealandica . According to Brinck (1977) the athetines listed in his paper were identified by Georg Benick, and that synonymy should probably be attributed to Benick. Erber and Hinterseher (1992) redescribed A. maderensis based on specimens from Madeira. They noted that Brinck (1977) incorrectly synonymized A. maderensis with A. zealandica, an opinion further supported by the comparison (made by Peter Hammond) of Erber and Hinterseher’s Madeiran specimens of A. maderensis and the specimens (types) of A. zealandica deposited in BMNH (see Erber & Hinterseher 1992 for details). From the original description (Likovský 1963) and redescription (Erber & Hinterseher 1992) of A. maderensis it is clear that the latter is not conspecific with A. pasadenae .

The types of Atheta pseudolaticollis were not examined, but the illustration of the distinctive spermatheca (Fig. 1 in Erber & Hinterseher 1992) as well as the shape of the aedeagus and the four projections at the posterior margin of the male abdominal tergite 8 leave no doubt that the types of A. pseudolaticollis are conspecific with the types of Atheta pasadenae . Therefore, A. pseudolaticollis and its objective synonym (replacement name) A. atlantidum are confirmed synonyms of A. pasadenae .

The types of Atheta immucronata were not examined, but the illustration of the distinctive spermatheca (Fig. 7 in Pace 1999) as well as the shape of the aedeagus, including the distinctive sclerites of the internal sac (Fig. 5–6), and the presence of four projections at the posterior margin of the male abdominal tergite 8 (Fig. 4) leave no doubt that the Chilean specimens examined by Pace are conspecific with the types of Atheta pasadenae . Apparently, Pace incorrectly illustrated the midline setation of the pronotum as being directed posteriad in the posterior half of the pronotum (Fig. 4). In fact, in all examined specimens of A. pasadenae the midline setation is directed anteriad along the entire length of pronotum as illustrated in Fig. 1 by Tronquet (2000). Atheta immucronata is therefore treated as junior synonym of A. pasadenae .

The types of Atheta gulosa were not examined, but the detailed illustrations of the male and female genitalia as well as a comparison of A. gulosa, A. laticollis (Stephens, 1832) and A. fimorum (Brisout de Barneville, 1860) (see Tronquet 2000) leave no doubt that Atheta gulosa and A. pasadenae represent the same species. The examined nontype specimens from France received from Marc Tronquet and originally identified by him as A. immucronata are identical with the types of A. pasadenae .

The types of A. pseudoinsulana were not examined but the illustrations of the male and female genitalia as well as abdominal tergite 8 (Figs. 13–19 in Klimaszewski et al. 2002) perfectly match those of the types of A. pasadenae and the examined specimens from Tristan da Cunha archipelago. For this reason A. pseudoinsulana is treated as a synonym of A. pasadenae .

Atheta dilutipennis sensu Muona 1984 was shown to be a misidentification (Klimaszewski et al. 2002). The illustration of the spermatheca by Muona (1984: Fig. 1) is quite schematic. However, considering that Atheta pasadenae is known from California, and it is the only North American species fitting the illustration (Muona 1984), it seems reasonable to attribute Muona’s (1984) records to A. pasadenae .

Subgeneric placement. One of the junior synonyms of A. pasadenae, Dimetrota vaniuscula is the type species of the subgenus Dimetrotina Casey, 1911 of the genus Atheta Thomson, 1858 . Originally, Casey introduced Dimetrotina as a subgenus of Dimetrota Mulsant & Rey, 1873, but in the current consensus classification of athetines (e.g. Smetana 2004b, Schülke & Smetana 2015) Dimetrota is treated as valid subgenus of Atheta while Dimetrotina is listed as a junior synonym of Dimetrota . However, unlike all the other species currently placed in Dimetrota, in A. pasadenae the pronotal hypomera are invisible in lateral view and the distal part of spermatheca is distinctly enlarged. Based on these characters, Atheta pasadenae cannot be placed in subgenus Dimetrota, and Dimetrotina cannot be considered a synonym of the former.

Atheta pasadenae is in many respects similar to A. laticollis (Stephens, 1832), the type species of the subgenus Mycetota Ádám, 1987 . Characters shared by the two species include pronotal hypomera invisible in lateral view, the same pronotal setation pattern, the quadri-dentate posterior margin of male abdominal tergite 8, the distinctly enlarged distal part of spermatheca and the general shape of aedeagus. Based on these characters, the subgeneric name Mycetota is synonymized with the older name Dimetrotina and both A. pasadenae and A. laticollis are treated here as members of Dimetrotina . Species with a similar combination of characters, particularly the distinctly enlarged distal part of the spermatheca, are known in two other subgenera of Atheta: Oxypodera Bernhauer, 1915 and Xenota Mulsant & Rey, 1874 a. In all species of Oxypodera for which the spermatheca has been illustrated, its distal part is enlarged in a way similar to A. laticollis and A. pasadenae (e.g. Figs. 121, 122, 127, 134 in Pace 1985). Many species described as members of Xenota have the spermatheca modified in the same way (e.g. A. kitalensis Pace, 1995 (Fig. 160 in Pace 1995) and A. cincta Pace, 1995 (Fig. 162 in Pace 1995)), but the type species of Xenota, A. myrmecobia (Kraatz, 1856), has a completely different general spermathecal ground plan (see Fig. 128 in Strand & Vik 1964), suggesting that the species with the modified spermatheca were misplaced and should be transferred to Oxypodera or Dimetrotina . Molecular phylogenies of Elven et al. (2010, 2012) placed A. pasadenae and A. laticollis in a well-supported clade that also included one species of subgenus Oxypodera and two species of the genus Mocyta Mulsant & Rey, 1874 b (formerly treated as a subgenus of Atheta). Atheta (Xenota) myrmecobia, on the other hand, was not a member of that clade (Elven et al. 2010). To conclude, both morphological and molecular data support close relationship between Dimetrotina and Oxypodera . What is not sufficiently clear is how exactly the two are related to Mocyta, a group lacking the distinctive enlargement of the distal part of the spermatheca. Additional species of Mocyta and Oxypodera need to be sequenced and included in molecular phylogenetic analyses to resolve this problem. Ádám (2010) also discussed the similarity between Mycetota and Oxypodera, and proposed to treat the two as separate subgenera of Atheta pending further study.

Geographical distribution. Atheta pasadenae has an almost cosmopolitan distribution and is now known from North America (U.S.A.: California and Nevada), South America (Chile (Pace 1999)), Southern Pacific (Juan Fernandez Archipelago), Hawaii (Kauai (Muona 1984)); Europe (France (Tronquet 2000)), Northern Atlantic (Madeira (Jansson 1940); Canary Islands (La Palma (Erber & Hinterseher 1992); Tenerife (Hernandez et al. 1994); Gran Canaria (Machado & Oromí 2000) and El Hierro (Assing 2000)) and the Azores (Brinck 1977)); Southern Atlantic (Tristan da Cunha archipelago: Tristan da Cunha, Nightingale and Inaccessible Island (Brinck 1977)); New Zealand; and Northern Africa (the latter without specifying the country and exact locality (Brinck 1977)). Interestingly, A. pasadenae has not been recorded in Africa south of the Sahara. Several species from the Republic of South Africa with male and female genitalia very similar to those of A. pasadenae were found in the collection of BMNH, but none of them exactly matched A. pasadenae (personal observation). It should be pointed out that some of the older records of Atheta laticollis, e.g. from Canary Islands (Uyttenboogaart 1930; Israelson et al. 1982), may be based on specimens of Atheta pasadenae .

The very wide distribution of A. pasadenae is clearly the result of multiple (unintentional) introductions by humans. Transoceanic colonization of distant continents and remote islands by a small beetle without assistance by humans does not seem feasible. On the other hand, ships involved in the world trade could have easily contributed to expansion of A. pasadenae, by providing habitats suitable for the beetle, when transporting cattle, fodder or simply ship ballast. The role of humans is particularly well documented for northern transatlantic introductions thanks to Lindroth’s (1957) classical study of the faunal connections between Europe and North America. An interesting question is what the original natural distribution range of A. pasadenae was.

In Table 1 the countries or islands where the species has been recorded so far are sorted by the date of the earliest known collecting event. The earliest records of A. pasadenae are from California and New Zealand. It is likely that both are not a part of the original natural distribution range. In North America, there are no native species related to A. pasadenae, and based on published information, the distribution of A. pasadenae is restricted to Nevada and coastal parts of California, where other introduced staphylinid species occur (particularly, from Europe). In New Zealand, the species was recorded only from disturbed coastal areas, and no related species occur there. Considering that continental European athetines have been subject to intensive collecting and identification by many coleopterists, it is extremely unlikely that the species as conspicuous as A. pasadenae could have evaded detection prior to 1990-ies. Therefore the species was introduced to Europe quite recently, and is not of European origin. Endemics of small oceanic islands are not invasive and many of them are wingless, while A. pasadenae has fully developed wings and is often collected with window traps or car nets. Therefore the species could not have originated from one of the Atlantic or Pacific islands. Africa south of the Sahara is the center of diversity of the Atheta subgenus Oxypodera . In their database, Newton and Thayer (2013) list 38 species of Oxypodera, and all but one are distributed in Africa. Species of Oxypodera share with A. pasadenae the distinctly enlarged distal part of the spermatheca. Additionally, many species of Oxypodera are similar to A. pasadenae in having pronotal hypomera invisible in lateral view, the same pronotal setation pattern and the posterior margin of the male abdominal tergite 8 quadri-dentate. This similarity suggests close phylogenetic relationship between A. pasadenae and the African Oxypodera (see Subgeneric placement) and indicates that A. pasadenae may have its origin in Africa even though it has not been recorded there. African athetines are poorly known and most parts of the continent have not been subject to modern taxonomic revisions. For this reason, I consider the recorded presence in Africa of close relatives of A. pasadenae as more indicative of the species origin than the lack of records of A. pasadenae in a region that has not been adequately studied. South Africa may be the best candidate for the area of origin of A. pasadenae, due to similar climatic conditions as in the regions where the species was supposedly introduced and established.