Eleusis bicolor ( ERICHSON, 1840 )

Irmler, Ulrich, 2017, The Neotropical species of the genus Eleusis LAPORTE, 1835 with description of the new genus Eleusima (Coleoptera: Staphylinidae: Osoriinae), Beiträge Zur Entomologie = Contributions to Entomology 67 (2), pp. 275-318 : 294-296

Eleusis bicolor ( ERICHSON, 1840)

Figs 19 A-C, 30E,31C, 33, 35d

Isomalus bicolor ERICHSON, 1840: 839

Eleusis cephalotes BERNHAUER, 1904: 218 new synonymy

Eleusis puncticeps BERNHAUER, 1912: 26 new synonymy

Type material examined: female, Holotype: Mexico: coll. Chevrolat ( BMNH); female holotype, male cotype of Eleusis cephalotes : Mexico: leg. Koltze ( FMNH, NMW); male type of Eleusis puncticeps: Columbia : Cali, Alto de las Cruces, 2200 m elev. Rio Vitaco , Sept. 1908, leg. Fassl ( FMNH); 1 male, 1 female cotypes: Rio Aquatal, 1800 m elev. Oct. 1908, leg. Fassl ( FMNH, NMW). According to the description of Erichson, the type specimen was labelled “Habitat in Mexico ” with the addition “Dom Chevrolat”. The type specimen was deposited in the collection of Chevrolat and transferred via Sharp to the BMNH.

Additional material examined: Mexico: Mexico, without more data, female ( IRSNB) ; 1 male, 2 females, ded. Koltze without more data, ( NMW) ; 200 m elevation, coll. Kraatz, without more data, 3 females ( SDEI) ; Hidalgo, 19.4 km S san Luis Potosi, Hidalgo border, Hwy. 85, 1200 m elev., 1 male, 1 female, under bark, 11.7.1990, leg. J.S. Ashe, K.J. Ahn, R. Leschen ( KNHM) ; Veracruz, 2.5 km S Jalapa , 1370 m elev., under bark, 2 males, 13 females, 26.5.1991, leg. J.S. Ashe #6 (12 KNHM, 3 UIC) ; Veracruz, 2.3 km S Jalapa , 1320 m elev., under bark, 13.7.1991, leg. J.S. Ashe #58 ( KNHM) ; Chiapas, Volcan Tacana, Sumidero San Antonio, under thin bark fresh cut log, montane trop. forest, 1760 m elev., female, 26.12.1976, leg. H. Frania ( AMNH) ; Jalapa , male, leg. Schneider ( NMW) ; Orizaba , 1 male, 1 female, 5.5.1871, Nov. 1871, leg. Bilimek ( NMW) ; Aruna , male, April 1867, leg. Bilimek ( NMW) ; Guatemala: Senahu , male, 1 female, col. Münchemeyer without more date ( NMW) ; Sacatepéquez, Antigua, SE Finca El Pilar (-90.59125, 14.52143), 2500-2600 m elev., under bark, 2 males, 9 females, 17.11.2016, leg. Z.H. Falin #GUAT1F16002 (10 KNHM, 2 UIC) ; Honduras: Santa Barbara, Mt. Santa Barbara, 11.5 km S & 5.6 km W Peña Blanca (14°57'N, 88°05'W), 1800 m elev., under bark, decaying slash, 3 females, 20.6.1994, leg. R. Brooks, J.S. Ashe, #167 ( KNHM) ; Morazan, 30 km E Tegucigalpa, Cerro Uyúca (14°02'N, 87°05'W), 1800 m elev., malaise trap, male, 10.6.1994, H. & A. Howden ( KNHM) ; Francisco Morazán, 10 km W Zamorano, Cerro Uyúca (14°02'N, 87°05'W), 1910 m elev., cloud forest beating, male, 18.7.1994, leg. R. Anderson #211 ( KNHM) ; Francisco Morazán, 12 km W Zamorano, Cerro Uyúca (14°02'N, 87°05'W), 1870 m elev., under bark, 4 males, 4 females, 6.6.1994, leg. Ashe & Brooks, Colln #002 (6 KNHM, 2 UIC) ; 1 male, 2 females from same location and collectors, but 9.7.1994 ( KNHM) ; El Paraiso, 6.9 km W Yuscarán, Cerro Monserrat (13°55N, 86°24'W), 1760 m elev., under bark, 4 males, 4 females, 7.6.1994, leg. Ashe, Brooks, #019 (6 KNHM, 2 UIC) ; 2 males from same location and same collectors, but flight intercept trap, 11.- 27.6.1994 ( KNHM) ; Paraiso, Cerro Monserrat, 7 km SW Yuscarán (13°55'N, 86°54'W), 1800 m elev., malaise trap, female, 30.5.1994, leg. H. & A. Howden ( KNHM) ; female from same location and same collectors, but 8.6.1994 ( KNHM) ; Ocotepeque, 24 km E Ocotepeque, El Guisayote (14°25'N, 89°04'W), 2170 m elev., roadside slash, male, 14.6.1994, leg. J. Ashe, R. Brooks ( KNHM) , #099 ( KNHM); Guatemala: Baja Verapaz, 4 km S Purulhá , 1650 m elev., under bark, 7 males, 6 females, 2.7.1993, leg. J.S. Ashe, R.W. Brooks, #181 (10 KNHM, 3 UIC) ; Baja Verapaz, 8 km S Purulhá , 1660 m elev., on dead Cecropia , male, 20.6.1993, leg. R. Anderson, #03-30 ( KNHM) ; 3 females from same location and same collector, but 1650 m elev., Cecropia treefall 29.6.1993, #149 ( KNHM) ; Sactatepeguez , 5 km SE Antigua (14.52779°, -90.68971°), 2350 m elev., sifted, leaf litter, oak forest, female, 6.6.2009, #LLAM09Wa-B-08-2-all ( KNHM) ; San Marcos, Parque Municipal Refugio del Quetzal (14.93946°, -91.87296°), 1810 m elev., cloud forest, flight intercept trap, female, 4.- 11.6.2015, leg. Z.H. Falin, #GUAT1F15099 ( KNHM) ; Quetzaltenango , 14.4 km SW Zunil, 1340 m elev., crustose fungi, 20.6.1993, leg. J. Ashe, R. Brooks ( KNHM) ; Nicaragua: Matgalpa Dept., 6 km N Matagalpa, Selva Negra Hotel (12°59.99'N, 85°54.53'W), 1350 m elev., 1 male, 1 female, Heliconia fruits, 20.5.2002, 1 female, under bark, 21.5.2002, leg. R. Brooks, Z. Falin, S. Chatzimanolis, #NIC1BFC02023 ( KNHM) ; Costa Rica: Cartago Prov., Tapanti Nat. Park , tributary river channel (9.69922°N, 83.78233°W), 1600 m elev., primary forest, under bark, 2 males, 3 females, 18.3.2010, leg. Z.H. Falin (3 KNHM, 2 UIC) ; same location (9°45.41'N, 83°47.5'W), 1150 m elev., under bark, 1 male, 1 female, 18.7.2000, leg. J. Ashe, R. Brooks, Z. Falin, #CR1ABF00167 ( KNHM) ; same location (9°45.41'N, 83°47.5'W), flight intercept trap, female, 17.- 20.7.2000, leg. J. Ashe, R. Brooks, Z. Falin, #CR1ABF00192 ( KNHM) ; 4 km NE Canon, Genesis II, Cerro de la Muerte, 2350 m elev., malaise trap, 1 male, 2 females, 1.2.- 30.3.1995, 1.- 30.6.1996, leg. P. Hanson #CR1H95-9611 ( KNHM) ; San José, Zuruqui de Moravia (10°03'N, 84°01'W), 1600 m elev., 2 males, 1 female, Feb.1993, P. Hanson ( KNHM) ; same location, same collector, malaise trap, 3 males, 1.- 30.4.1995, 1.- 30.5.1995, 1.- 30.10.1995, #CR1H95-9628/12/02 (2 KNHM, 1 UIC) ; 26 km N San Isidro , 2100 m elev., Feb.- May 1992, leg. P. Hanson ( KNHM) ; Dulce Novembre, Vivero “Linda Vista”, 1300 m elev., malaise trap, female, June-August 1993, leg. P. Hanson ( KNHM) ; 31 km N San Isidro del General, near 105 km Marker Rt. 2, 7600 ft. elev., litter, 3 males, 4 females, 26.2.1985, leg. L. Herman ( AMNH) ; Puntarenas Prov., Altamira Biol. Sta. Trail to Valle de Silencio (9°01.76'N, 83°00.49'W), 1600-1700 m elev., under bark, 2 males, 3 females, 6.6.2004, leg. J. Ashe, Z. Falin, I. Hinojosa, #CR1AFH04127 (4 KNHM, 1 UIC) ; Puntarenas, San Vito, Estac. Biol. Las Alturas , 1875 m elev., 2 males, Sept.-Nov.1992, leg. P. Hanson ( KNHM) ; La Reserva de Monteverde ,, ca. 4 km E Monteverde, 5000- 5500 ft. elev., 4 males, 4 females, 4.3.1985, leg. L. Herman #2150 ( AMNH) ; Las Alturas Field Station , 20 km N San Vito de Hava, 1400 m elev., malaise trap, male, 10.- 31.7.1992, leg. Snyder ( AMNH) ; Las Alturas Field Station , 1400 m elev., malaise trap, male, 17.- 21.6.1991, leg. DeVries ( AMNH) ; Puntarenas-Guanacaste border, Monte Verde, Cerro amigos, 1760 m elev., flight intercept trap, female, 12.5.1989, leg. J. Ashe, R. Brooks, R. Leschen, #123 ( KNHM) ; Guanacaste, Cacao Biological Station (10°55.38'N, 85°27.7'W), 1050 m elev., under bark of fermenting tree, female, 11.7.2000, leg. J. Ashe, R. Brooks, Z. Falin #CR1ABF00104 ( KNHM) ; Heredia, Cerro Chompipe, 2 km N Monte de la Cruz (10°05.2'N, 84°04.3'W), 2000 m elev., berlese forest litter, 1 male, 2 females 12.6.1997, leg. R. Anderson, #CR1A97012J ( KNHM) ; La Selva, 3.2 km SE Puerto Viejo , 100 m elev., flight intercept trap, female, 27.3.1992, leg. W. Bell ( KNHM) ; Paso Llano, Falda 5.0 Volcan Barva, 2300 m elev., male, 4.3.1991, leg. H.J. Lzama ( KNHM) ; Guanacaste Prov., 8 km NE Sta. Sta. Elena, Sta. Elena Forest Res. (10°20.70'N, 84°47.89'W), 1640 m elev., flight intercept trap, female, 11.- 17.6.2001, S & J Peck, #CR1P01004 ( KNHM) ; PanAmerican Hwy, km 80.5, 9 km SSW Albergue de Montana Savegre, Upper Quebrada –Las Robles Trails (9°32.56'N, 83°48.9'W), 2200-2300 m elev., under bark, 1 male, 1 female, 23.7.2000, leg. J. Ashe, R. Brooks, Z. Falin #CR1ABF00234 (1 KNHM, 1 UIC) ; Panama: Chiriqui, 6.0 km NE Boquete (8°48.0'N, 82°26.0'W), 1550 m elev., flight intercept trap, male, 14.- 19.6.1996, leg. J. Ashe, R. Brooks, #PAN1AB96179B ( KNHM) ; 27.7 km W Volcan, Hartmann’s Finca (8°45'N, 82°48'W), 1450 m elev., under bark, 1 male, 3 females, 14.6.1995, leg. J. Ashe, R. Brooks, #211 ( KNHM) ; 5.9 km N Cerro Punta, Par. Nat. Volcan Baru (8°22'N, 82°34'W), 2150 m elev., alder forest litter, male, 14.6.1995, leg. R. Anderson #PAN2A9522A ( KNHM) .

Diagnosis: The species is extremely varying in size and colouration. In particular the size of the head is varying without developing a sexual dimorphism. Whereas the length of the eyes seems to be approximately constant, the length of temples varies extremely. Specimens exist with temples directly narrowed behind eyes or with long parallel temples. Thus, in some specimens the eyes are shorter than temples, in other specimens, temples are more than twice as long as eyes. The species resembles E. struyvei in colouration and shape of head and pronotum. On average, it is smaller than the similar E. struyvei . More differences are described in E. struyvei .

Description: Length: 4.5 – 8.0 mm; Colouration: extremely variable; head and pronotum black; elytra black or with varying large yellow spot in anterior half, at least posterior quarter blackish; abdomen yellow with abdominal segments VII partly, VIII, and IX totally black or central parts of all abdominal segments brown and last segments darker brown; legs dark yellow; antennae dark brown.

Head: on average, 1.12 mm long, 1.24 mm wide; varying corresponding to total length ( Fig. 33 ); eye length constantly 0.18 mm; length of temples varying; sides of temples approximately parallel; preocular sides shortly parallel to base of antennae; anterior margin of clypeus sinuate with central part prominent; supraocular groove reaching from anterior edge of eyes to posterior edge of temples; size and density of punctation irregular; triangular space between eyes with coarse and dense punctation; on clypeus and posterior vertex punctation weaker and sparser; at each end of supraocular groove with setiferous puncture; second pair of setiferous punctures at prominent part of clypeus; elongate microsculpture irregularly dense; longitudinally striate; surface shiny.

Antennae slightly shorter than head and pronotum combined; in specimens with short head as long as head and pronotum combined; first antennomere longer and thicker than following antennomeres; second antennomere half as long as first; third antennomere longer than second but shorter than first; length of following antennomeres decreasing; width increasing; shape of penultimate antennomeres triangular; at apex, as wide as long; antennomere five to eleven with long black setae.

Pronotum: on average, 0.70 mm long, 0.79 mm wide; size varying corresponding to total size; widest close to anterior angles; sides in anterior half parallel; narrowed in posterior half in smooth convex curve or directly narrowed in wide convex curve to posterior angles; short groove at anterior angles; another pair of short grooves close to posterior angles, margined by indistinct ridge; punctation as dense and deep as on vertex; three to four setiferous punctures at anterior margin close to each anterior angle; two setiferous punctures in anterior lateral grooves; several setiferous punctures along lateral margin; weak longitudinal microsculpture; with wide polished areas on disc; surface shiny.

Elytra: on average, 1.01 mm long, 0.98 mm wide, size varying corresponding to total size; sides slightly widened to posterior angles; humeral angles distinct; punctation similarly dense and deep as on pronotum; one setiferous punctures on central disc on each side of suture; several setiferous punctures along lateral margin and close to posterior angles; longitudinal microsculpture weak; surface shiny.

Abdomen nearly impunctate except few setiferous punctures in transverse row of each abdominal segment.

Aedeagus in lateral aspect slender with obtusely rounded apex; ventral plate more sclerotised than remaining central lobe; small plate at apex darker; ventral plate with numerous sensillae; in ventral aspect, approximately parallel; parameres as long as central lobe; widened at apex in transparent lobe; few sensillae and short setae at apex.

Figures

Fig. 18–23: Eleusis platysoma (18), E. bicolor (19), E. struyvei (20), E. fenestrata (21), E. rufula (22), E. adusta (23): aedeagus in lateral (A) and ventral (B) view, antenna (C), head (D), colouration of elytra (E); scale bar A, B: 0.1 mm, C: 0.2 mm, D, E: 1.0 mm.

Fig. 33: Head and elytra of E. bicolor showing variance among head size (upper row) and colouration of elytra (lower row);