Emplenota Casey, 1884

Yamamoto, Shûhei & Maruyama, Munetoshi, 2012, Revision of the Seashore-dwelling Subgenera Emplenota Casey and Triochara Bernhauer (Coleoptera: Staphylinidae: genus Aleochara) from Japan, Zootaxa 3517, pp. 1-52 : 7-11

Subgenus Emplenota Casey, 1884

( Figs. 1–52 , 93–97 , 101–103 )

Emplenota Casey, 1884: 17 (original description; type species: Emplenota maritima Casey, 1884: 17 , by original designation and monotypy); 1906: 131 (as genus; key of genera of subtribe “Aleocharae”), 172 (as genus; historical review; diagonostic key to species of Atlantic coast); Eichelbaum, 1909: 245 (as subgenus; generic catalogue of world Staphylinidae ); Fenyes, 1920: 399 (as subgenus; key of world subgengera of Aleochara ), 1921: 415 (as subgenus; diagnosis; catalogue of world species); Scheerpeltz, 1925: 447 (as subgenus; catalogue of Palaearctic species of Aleocharinae ); Bernhauer & Scheerpeltz, 1926: 795 (as subgenus; catalogue of world species of Aleocharinae ); Tottenham, 1949: 404 (as subgenus; generic catalogue of British Staphylinidae ); Blackwelder, 1952: 147 (as subgenus; generic catalogue of world Staphylinidae ); Hatch, 1957: 137 (as subgenus; key to Aleochara subgenera of Pacific Northwest), 140 (redescription of species of Pacific Northwest); Likovsky, 1974: 294 (as subgenus; key of subgenera of middle Europa); Moore & Legner, 1975: 328 (as subgenus; catalogue of Nearctic species); Seevers, 1978: 59 (as genus; key to Nearctic genera of Aleocharinae ), 138 (diagnosis); Klimaszewski, 1984: 9, 10 (phylogenetic relationships of Nearctic Aleochara ), 95 (as subgenus; revision of Nearctic Aleochara ; redescription of subgenus), 96 (key; redescriptions of Nearctic species); Lohse, 1984: 148 (as genus; diagnosis); Lohse, 1985: 328 (as genus; key of middle European species of genera Emplenota and Polystomota ); Lohse, 1989: 239 (as genus; key to genera for middle Europe), 240 (as genus; catalogue of middle European species); Assing, 1995: 219 (as genus; diagnostic key to genera), 219 (notes on genus), 220 (key to Palaearctic species), 220 (descriptions of each species); Welch, 1997: 8 (historical review of British Emplenota and related taxa); Maus & Ashe, 1998a (online) (as subgenus; checklist of subgenus of world; diagnosis of subgenus; bionomics; discussion of phylogenetic relationships); Ashe, 2001: 360 (as subgenus; catalogue for Nearctic species); Smetana, 2004: 356 (as subgenus; catalogue for Palaearctic Aleocharinae ); Dauphin, 2005: 47 (as genus; key to genera of Emplenota and Polystomota ); Gouix & Klimaszewski, 2007: 26 (as subgenus; catalogue of Aleocharine species of Canada and Alaska).

Polystoma Stephens, 1833: 91 (original description; type species: Aleochara obscurella Gravenhorst, 1806: 159 ; fixed by Stephens, 1833: 91, by monotypy); Stephens, 1835: 430 (as genus; redescription of genus); Thomson, 1861: 47 (as genus; redescription of genus), 48 (key to Scandinavian species); Mulsant & Rey, 1874: 169 (as genus; detailed redescription of genus as Polystome [misspelling]), 172 (key to species of France), 173 (redescriptions of species of France); Fowler, 1888: 21 (as subgenus; diagnosis; diagnostic key to species of British Islands); Casey, 1894: 289 (as genus; as “ Polistoma ” [misspelling]: see, Casey, 1906: 272; later cited by some authors as synonym of Emplenota ); Ganglbauer, 1895: 45 (as subgenus; redescriptions of middle European species); Bernhauer, 1901a: 504 (as subgenus; redescriptions of Palaearctic species); Johansen, 1914: 31 (as subgenus; catalogue and key to species of Denmark); Fenyes, 1921: 415 (as synonym of Emplenota ); Scheerpeltz, 1925: 447 (as synonym of Emplenota ); Bernhauer & Scheerpeltz, 1926: 795 (as synonym of Emplenota ); Tottenham, 1949: 404 (as synonym of Emplenota ; note); Blackwelder, 1952: 147, 318 (as synonym of Emplenota ); Palm, 1972: 443 (as subgenus; catalogue; redescriptions of species of Sweden); Moore & Legner, 1975: 328 (as synonym of Emplenota ); Klimaszewski, 1984: 95 (as synonym of Emplenota ); Lohse, 1985: 328 (as synonym of Emplenota ); Smetana, 2004: 356 (as synonym of Emplenota ); Gouix & Klimaszewski, 2007: 26 (as synonym of Emplenota ).

Polystomota Casey, 1906: 136 (original description; type species: Aleochara grisea Kraatz, 1856: 96 ; fixed by Casey, 1906: 136, by original designation and monotypy); Eichelbaum, 1909: 245 (as genus; generic catalogue of world Staphylinidae ); Fenyes, 1921: 415 (as synonym of Emplenota ); Scheerpeltz, 1925: 447 (as synonym of Emplenota ); Bernhauer & Scheerpeltz, 1926: 796 (as synonym of Emplenota ); Blackwelder, 1952: 147, 319 (as synonym of Emplenota ); Moore & Legner, 1975: 328 (as synonym of Emplenota ); Seevers, 1978: 138 (as synonym of Emplenota ); Lohse, 1985: 328 (as synonym of Emplenota ); Lohse, 1989: 239 (as genus; key to genera and species of middle Europe); Assing, 1995: 219 (key to Asian coastal genera), 226 (as genus; key to Palaearctic species), 229 (notes on species); Welch, 1997: 9 (historical comment); Maus & Ashe, 1998b (online) (world checklist of subgenus; diagnosis; bionomics; phylogenetic relationships); Smetana, 2004: 357 (as subgenus; catalogue of Palaearctic species); Dauphin, 2005: 47 (as genus; key of genera, Emplenota and Polystomota ); Frank & Ahn, 2011: 20 (as subgenus; checklist of coastal Staphylinidae of world).

Polycharina Reitter, 1909: 28 (original description; type species: Aleochara grisea Kraatz, 1856: 96 ; fixed by Reitter, 1909: 28, by monotypy); Fenyes, 1921: 415 (as synonym of Emplenota ); Scheerpeltz, 1925: 447 (as synonym of Emplenota ); Bernhauer & Scheerpeltz, 1926: 796 (as synonym of Emplenota ); Blackwelder, 1952: 147, 317 (as synonym of Emplenota ); Moore & Legner, 1975: 328 (as synonym of Emplenota ); Lohse, 1985: 328 (as synonym of Emplenota ).

Polystomaria Reitter, 1909: 28 (original description; type species: Aleochara obscurella Gravenhorst, 1806: 159 ; fixed by Reitter, 1909: 28); Scheerpeltz, 1925: 447 (as synonym of Emplenota ); Fenyes, 1921: 415 (as synonym of Emplenota ); Bernhauer & Scheerpeltz, 1926: 796 (as synonym of Emplenota ); Blackwelder, 1952: 147, 319 (as synonym of Emplenota ); Moore & Legner, 1975: 328 (as synonym of Emplenota ); Klimaszewski, 1984: 95 (as synonym of Emplenota ); Lohse, 1984: 148 (as genus; diagnosis, as Polystomaria Casey ); Lohse, 1985: 328 (as synonym of Emplenota ); Smetana, 2004: 356 (as synonym of Emplenota ); Gouix & Klimaszewski, 2007: 26 (as synonym of Emplenota ).

Redescription. Body ( Figs. 1–5 ): moderately flattened, slender and subparallel sided; whole length varying from 2.5 to 7.0 mm, normally around 3.5–4.5 mm; dorsal surface covered with minute and dense hexagonal microstructures; surface of head, pronotum and elytra covered with somewhat dense, thin hairs. Dorsal surface of abdomen shining, but head, pronotum and elytra mat (uniformly hexagonal-reticulated). Colour ( Figs. 1–5 ): uniformly blackish brown to black sometimes with lighter colour in elytra. Head: almost circular or somewhat oval (HW/HL ≈1.14), moderately convex above, widest around middle; dorsal surface gently elevated medially, but sometimes with unique elevation partially; impunctate on medial line (e.g., Fig. 6 ). Eyes small, not strongly protruding laterally. Antennae ( Figs. 1–5 , 8 ): more or less filiform, entirely robust and long, as same as combined length of head and pronotum; segment I stout and apically dilated; and segment XI cleary long. Mouth parts: mandibles asymmetric, left one with one tooth near apex. Clypeus rounded apically. Labrum (e. g., Fig. 12 ) about 1.7 times as wide as long; anterior margin moderately emarginated medially; basal half semi-transparent. Labial palpus ( Fig. 9 ) with segment I clearly longer than II; segment II dialated. Mentum ( Fig. 11 ) much wider than long, nearly trapezoidal; anterior margin strongly emarginated; numerous pseudopores scattered randomly. Maxillary palpus ( Fig. 10 ) distinctly segmented; segment I long and thick; segment II shorter and narrower than I; segment III slightly shorter and narrower than II; pseudosegment much shorter than other segments; lacinia with numerous hairs and with about 11 thick spines pectinately. Thorax: pronotum oval and somewhat transverse (PW/PL ≈1.24), longer than head length (PL/HL ≈1.25), somewhat broader than head (PW/HW ≈1.36), widest around middle, moderately constricted near base; outer margin around middle with a pair of relatively long blackish macrosetae; surface flat and evenly pubescent but sometimes with deep and distinct punctures on dorsal surface numerously. Hypomera fully visible in lateral view. Inter coxal cavities of mesoventrite (e.g., Fig. 7 ) narrowly or moderately separated. Mesoventrite with short carina ( Fig. 7 : arrow), or not carinate. Elytra: widened toward posterior margin, much broader than long (EW/EL ≈1.56), and somewhat wider than pronotum (EW/PW ≈1.28); posterior margin of each elytra nearly truncate but gently rounded toward posterior margins; surface somewhat rugosely punctured both hexagonal microsculptures and prominent distinct punctures in some species; entire surface densely covered with brown setae; anterior margin with one relatively long blackish bristle. Legs (e. g., Fig. 13 ): short and slender with short hind tarsi; numerous spines and bristles on dorsal surface of each tibia, especially on foretibia ( Fig. 13 ); midtibia as long as metaventrite; each tarsal segment almost same width (segment V excluding claws); hindtarsi short (hind tarsal length/mid tarsal length ≈1.31). Hind wings: entire; veins weakly sclerotized and very obscure; posterior margin with a row of minute white hairs. Abdomen: elongated and slightly narrowed toward posterior segments, narrowing abruptly around apex, widest around segment III–IV; at least tergite III–VI ( Figs. 1–5 ) transversely impressed at base. Surface of tergite VIII and sternite VIII simple and smooth. Posterior margin of tergite VIII ( Fig. 14–15 , 23–24 , 30–31 , 38–39 , 46–47 ), bearing thick and short several sensory setae (see, Fig. 14 : arrow).

[Male]: posterior margin of sternite VIII ( Figs. 16 , 25 , 32 , 40 , 48 ) normally pointed, and its shape varies among species. Median lobe ( Figs. 18–19 , 27–28 , 34–35 , 43–44 , 50–51 ) elongated, widest around base. Median lobe with a pair of subapico-ventral projections (see, Fig. 18 ) on median lobe; prominent inner sac with long projecting flagellum (e. g., Figs. 18–19 , 43–44 ) at least almost as long as median lobe of aedeagus. Paramerite longer than median lobe of aedeagus; apical lobe of paramerite ( Fig. 21 ) short and pointed, bearing with four setae.

[Female]: posterior margin of tergite VIII, almost truncate, rounded or slightly emarginated; surface of tergite VIII ( Figs. 15 , 24 , 31 , 39 , 47 ) similar to that of male. Posterior margin of sternite VIII ( Figs. 17 , 26 , 33 , 41 , 49 ) slightly or moderately pointed. Spermatheca ( Figs. 22 , 29 , 37 , 45 , 52 ; see, Fig. 22 ) with apical invagination of spermatheca (ai) sharrow; spherical head of spermatheca (sh), as long as or longer than apical portion of spermathecal stem (sa); neck of spermatheca (sn) and (sa) forming more or less in right angle; basal portion of spermathecal stem (sb), narrowing toward base; distinct collar located between (sa) and (sb); sclerotized portion of spermathecal stem (ss) short and erect in most cases; membraneous portion of spermathecal duct (sm) moderate to long length; inner wall of (sh), (sa) and collar moderately striate; each part of spermatheca except for (sm) weakly Diagnosis. The members of this subgenus are similar in habitus to those of the tribe Athetini (e.g., genera Adota Casey, 1910 ; Psammostiba Sawada, 1976 ) found in Japanese seashore, but are discriminated from them by the following character states: antennae shorter, somewhat shorter or almost same as combined length of head and pronotum; maxillary palpi with four segments and a pseudosegment; labial palpi with three segments and a pseudosegment; tarsal fomula: 5-5-5; [Male]: median lobe of aedeagus with a prominent flagellum; a pair of subapico-ventral projections on median lobe (see, Figs. 18–19 ); [Female]: spermatheca lack of any coiling part; spermathecal stem with a distinct collar (see, example of Fig. 22 ).

As sympatric species of Aleochara , A. (Coprochara) squalithorax Sharp, 1888 is also similar in general appearance, but differentiated from it as follows: body clearly flattened; antennae longer and slender, more or less shorter or longer than head and pronotum combined; dorsal surface of pronotum flattened; dorsal surface of pronotum smooth ( A. squalithorax Sharp, 1888 with rough surface and with elevated pronotum; see, also key of the littoral subgenera); [Male]: aedeagus with a pair of subapico-ventral projections ( Figs. 18–19 ); [Female]: spermatheca lack of coiling portion (e.g., Fig. 22 ) ( A. squalithorax , basally coiled numerous times).

Comments. Some species have a spherical or longitudinal elevation on the dorsal surface of the head base (e.g., Fig. 6 : arrow) and these are important character states for distinguishing between each species. Assing (1995) noted that different pronotal pubescence patterns can be discriminated between two geographical groups, namely, between those in North America and the eastern Palaearctic and those in the western Palaearctic. Klimaszewski (1984) redefined the subgenus and noted some important character states, including mesoventrite not carinate and antennae with fourth segment spherical; however, these characters are not important and are shared by only some species in the subgenus. Welch (1997) and Park and Ahn (2004) already pointed out the presence of a carina on the mesoventrite for some species, including Aleochara fucicola .

Emplenota species are parasitoids on the dipteran families: Anthomyiidae , Coelopidae , and Sepsidae . These dipteran families have hitherto been recorded as host agents ( Peschke & Fuldner, 1977; Maus et al., 1998b; Yamazaki, 2008, 2012). Descriptions of the larvae of the European species, Aleochara (Emplenota) obscurella Gravenhorst, 1806 (as A. algarum Fauvel, 1862 ) are in Lesne and Mercier (1922) and Paulian (1938, 1941: 313). Pupation takes place inside the puparia of flies ( Scott, 1920; Yamazaki, 2008, 2012).

Figures

FIGURES 1 – 7. Japanese species of Aleochara (Emplenota) (Figs. 1 – 5, habitus). 1. Aleochara (Emplenota) fucicola; 2. A. (E.) puetzi; 3. A. (E.) hayamai; 4. A. (E.) yamato; 5. A. (E.) segregata; 6. dorsal head of A. yamato; 7. mesoventrite and metaventrite of A. fucicola in ventral view.

FIGURES 8 – 13. Body parts of Aleochara (Emplenota) fucicola of male. 8. right antenna; 9. labium; 10. maxilla; 11. mentum; 12. labrum; 13. right foreleg in ventral view.

FIGURES 14 – 22. Terminalia of Aleochara (Emplenota) fucicola. 14. tergite VIII of male; 15. tergite VIII of female; 16. sternite VIII of male; 17. sternite VIII of female; 18. male genitalia: median lobe of aedeagus in lateral view; 19. male genitalia: median lobe of aedeagus in ventral view; 20. apical lobe of median lobe in ventral aspect; 21. apical lobe of paramerite, lateral view; 22. female genitalia: spermatheca.

FIGURES 23 – 29. Terminalia of Aleochara (Emplenota) puetzi. 23. tergite VIII of male; 24. tergite VIII of female; 25. sternite VIII of male; 26. sternite VIII of female; 27. male genitalia: median lobe of aedeagus in lateral view; 28. male genitalia: median lobe of aedeagus in ventral view; 29. female genitalia: spermatheca.

FIGURES 30 – 37. Terminalia of Aleochara (Emplenota) segregata. 30. tergite VIII of male; 31. tergite VIII of female; 32. sternite VIII of male; 33. sternite VIII of female; 34. male genitalia: median lobe of aedeagus in lateral view; 35. male genitalia: median lobe of aedeagus in ventral view; 36. apical lobe of median lobe in ventral aspect; 37. female genitalia: spermatheca.

FIGURES 38 – 45. Terminalia of Aleochara (Emplenota) hayamai. 38. tergite VIII of male; 39. tergite VIII of female; 40. sternite VIII of male; 41. sternite VIII of female; 42. right antenna of male; 43. male genitalia: median lobe of aedeagus in lateral view; 44. male genitalia: median lobe of aedeagus in ventral view; 45. female genitalia: spermatheca.

FIGURES 46 – 52. Terminalia of Aleochara (Emplenota) yamato. 46. tergite VIII of male; 47. tergite VIII of female; 48. sternite VIII of male; 49. sternite VIII of female; 50. male genitalia: median lobe of aedeagus in lateral view; 51. male genitalia: median lobe of aedeagus in ventral view; 52. female genitalia: spermatheca.

FIGURES 93 – 100. Collecting sites of the subgenera Emplenota and Triochara of the genus Aleochara in Japan. 93. Kourakaigan (Matsue-shi, Shimane-ken; habitat of A. (E.) fucicola, A. (E.) segregata, and A. (E.) hayamai; arrow); 94. drifted seaweed and flotsams on beach (Koura-kaigan); 95. Mochirippu-numa (Hamanaka-chô, Hokkaidô; A. (E.) puetzi, arrow); 96. Ochiishi-misaki (Nemuro-shi, Hokkaidô; A. puetzi); 97. Kakanokuketo (Shimane-ken; habitat of A. fucicola, A. segregata, A. hayamai, and the type locality of A. (E.) yamato; A. fucicola, arrow); 98. Hamamatsu (Nemuro-shi, Hokkaidô; habitat of A. (T.) nubis, arrow); 99. drifted seaweed on beach (Hamamatsu); 100. mating behaviour of A. nubis at Hamamatsu.

FIGURES 101 – 103. Collecting localities of Aleochara (Emplenota) spp. based on specimens examined. 101. A. (E.) fucicola (Pointed by black circle); 102. A. (E.) segregata (Pointed by black square); 103. A. (E.) puetzi (Pointed by black triangle); A. (E.) hayamai (Pointed by black diamond); A. (E.) yamato (Pointed by black star).