Dyscolotaxia championi Horn, 1890

Otto, Robert L., 2023, A revision of Dyscolotaxia Horn, 1890 (Coleoptera: Eucnemidae: Macraulacinae: Macraulacini), with the description of Amazotaxia new genus from South America, Insecta Mundi 2023 (21), pp. 1-15 : 4-6

Dyscolotaxia championi Horn, 1890

Fig. 5–9

Dyscolotaxia championi Horn 1890: 239 ; Table X, Fig. 17, 17a .

Differential diagnosis. The rounded last abdominal ventrite will distinguish D. championi from D. hispaniolensis new species. Quadrate antennal flagellomeres II–V will also distinguish this species from all other Dyscolotaxia species in the region.

Type. Not seen. Horn (1890) noted the male type was collected by Champion in Panama at Bugaba. The type for D. championi is placed in the collection of the Natural History Museum in London, United Kingdom.

Specimens examined. Twenty-six specimens were studied: COSTA RICA: Alajuela Province: “ Cano Negro, 20m, R.N .; V.S. Cano Negro, Prov.; Alajuela, Costa Rica, 4 a; 17 Dic 1992, K. Flores; L-N 319100, 450200” (1, MNCR); “ Playuelas, RNVS Caño Negro, Prov. Alaju ; COSTA RICA, 20m. 1–18 Feb. 1994. K.; Martínez, L N 325900_454500 #; 2686” (1, MNCR); Guanacaste Province: “COSTA RICA Guan ; 3km SE R. Naranjo; 22–25 Jan 1993; F.D. Parker ” (1, SEMC) ; Heredia Province: “COSTA RICA: Prov.; Heredia, F. La Selva ; 3 km S Pto. Viejo; 10°26′N 84°01′W ” / “ 23.vii.1976; H.A. Hispenheide ” (date handwritten) (1, MNCR) ; “COSTA RICA: Heredia; La Selva, 3.2 km SE; Puerto Viejo , 100 m; 3 Feb. 1992, W. Bell; ex.: flight intercept trap ” / “Collection of the Global; Eucnemid Research Project; (Robert L. Otto)” (green framed white label) (1, GERP) ; “COSTA RICA: Heredia; La Selva, 3.2 km SE; Puerto Viejo , 100 m; 18 Mar. 1992, W. Bell; ex.: flight intercept trap ” / “Collection of the Global; Eucnemid Research Project; (Robert L. Otto)” (green framed white label) (1, GERP) ; “COSTA RICA: Heredia; Pr: La Selva Bio.Sta. ; 3 km S Pto. Viejo; 10°26′N 84°01′W ” / “ 12 FEB 1993; Parceles Sucesionales; M/00/013” (1, MNCR) ; “COSTA RICA: Heredia; Est.Biol. La Selva , 50–; 150 m 10°26′N 84°01′W; Proy ALAS, INBio-OET” / “M/05/020; 02 Marzo 1993; Bosque primario” (1, MNCR) ; “COSTA RICA: Heredia; Est.Biol. La Selva , 50–; 150 m 10°26′N 84°01′W; Proy ALAS, INBio-OET” / “M/04/035; 15 Marzo 1993; Bosque primario” (1, MNCR) ; “COSTA RICA: Heredia; Est.Biol. La Selva , 50–; 150 m 10°26′N 84°01′W; Proy ALAS, INBio-OET” / “M/12/043; 16 Marzo 1993; Bosque primario” (1, MNCR) ; “COSTA RICA: Heredia; Pr: La Selva Biol, Sta. ; 3 km S Pto. Viejo; 10°26′N 84°01” / “ 11-iv-1993; P. Hanson; Malaise Trap ” (1, MNCR) ; “COSTA RICA: Heredia; Est.Biol. La Selva , 50–; 150 m 10°26′N 84°01′W; Proy ALAS, INBio-OET” / “M/12/075; 16 Abril 1993; Bosque primario” (1, MNCR) ; “COSTA RICA: Heredia; Pr: La Selva Biol, Sta. ; 3 km S Pto. Viejo; 10°26′N 84°01” / “iv– v-1993; P. Hanson; Malaise Trap ” (2, MNCR) ; “COSTA RICA: Heredia; Est.Biol. La Selva , 50–; 150 m 10°26′N 84°01′W; Proy ALAS, INBio-OET” / “ 19 Mayo 1993; M/12/106; Bosque primario” (1, MNCR) ; “COSTA RICA: Heredia; Est.Biol. La Selva , 50–; 150 m 10°26′N 84°01′W; Proy ALAS, INBio-OET” / “M/12/127; 14 Junio 1993; Bosque primario” (1, MNCR) ; “COSTA RICA: Heredia; Est.Biol. La Selva , 50–; 150 m 10°26′N 84°01′W; Proy ALAS, INBio-OET” / “M/12/134; 14 Junio 1993; Bosque primario” (1, MNCR) ; “COSTA RICA: Heredia; Est.Biol. La Selva , 50–; 150 m 10°26′N 84°01′W; Proy ALAS, INBio-OET” / “M/12/146; 1 Julio 1993; Bosque primario” (1, MNCR) ; “COSTA RICA: Heredia; Est.Biol. La Selva , 50–; 150 m 10°26′N 84°01′W; Proy ALAS, INBio-OET” / “M/09/159; 15 Julio 1993; Bosque secundario” (1, MNCR) ; “COSTA RICA: Heredia; Est.Biol. La Selva , 50–; 150 m 10°26′N 84°01′W; Proy ALAS, INBio-OET” / “M/12/202; 01 Setiembre 1993; Bosque primario” (1, MNCR) ; “COSTA RICA: Heredia; Est.Biol. La Selva , 50–; 150 m 10°26′N 84°01′W; Proy ALAS, INBio-OET” / “M/07/536; 02 Enero 1996; Bosque primario” (1, MNCR) ; “ COSTA RICA: Prov. Heredia ; Est. Biol. La Selva , 50 –; 150m 10°26′N 84°01′W; 24 Feb 2004; INBio-OET-ALAS transect” (date and month handwritten) / “ 24 Febrero 2004; Malaise; M/26/768” (1, MNCR) ; “ COSTA RICA: Prov. Heredia ; Est. Biol. La Selva , 50 –; 150m 10°26′N 84°01′W; 09 Marzo 2004; INBioOET-ALAS transect” (date and month handwritten) / “ 9 Marzo 2004; Malaise; M/26/778” (1, MNCR) ; “ COSTA RICA: Prov. Heredia ; Est. Biol. La Selva , 50 –; 150m 10°26′N 84°01′W; 21 Marzo 2004; INBio-OET-ALAS transect” (date and month handwritten) / “ 21 Marzo 2004; Malaise; M/27/789” (1, MNCR) ; Limón Province: “ Valle La Estrella, R.B. Hitoy Cerere, A.C .; Amistad, Prov. Limón, COSTA RICA. 100 ; m. Jul 1994, M. Segura, L S; 398100_572800 #3130” (1, MNCR); Puntarenas Province: “ Rancho Quemado, Pen. de Osa , A.C. Osa ; Prov. Punta , COSTA RICA, 200 m, 4-25 ; Ene 1994, A.L.Marín, L S; 292500_511000 #2577” (1, MNCR).

Redescription. Male. Length, 5.0–6.0 mm. Width, 1.25–2.0 mm. Body elongate; uniformly dark brown; scape, pedicel, and antennal flagellum dark reddish brown; legs including tarsi reddish brown; head, pronotum, and elytra clothed with short, recumbent, yellowish setae ( Figure 5 ). Head: Subspherical, with a faint indication of short median carina present on frons above antennal insertions; surface shiny, punctures somewhat deep, closely dispersed; apical margin of frontoclypeal region feebly trilobed, more than 2 times wider than base; interantennal carina present at base of frontoclypeal region; mandibles stout, bidentate, densely punctate. Antennae ( Fig. 6 ): Capitate with flagellomeres VI–IX forming an elongate club, reaching slightly more than 1/2 the length of the body; with last 2.5 segments extending beyond pronotal hind angles; flagellomere I elongate, almost twice as long as II; flagellomeres II and III subequal, each quadrate and shorter than IV; flagellomeres IV and V subequal, each longer than wide; flagellomeres VI–VIII subequal, each longer than wide and as long as flagellomeres III–V combined; flagellomere IX longer than VIII. Pronotum: Surface shiny; punctures somewhat deep, closely spaced; slightly longer than wide, with well developed hind angles; lateral sides parallel sided at basal 1/2 and arcuate at apical 1/2; disc convex without depressions or carinae; base sinuous. Scutellar shield: Triangular shaped, longer than wide, punctate, setose, and distally rounded. Elytra: Striae indicated as solid lines; interstices flattened; surfaces shiny, transversely rugose at humeri, very closely and shallowly punctate elsewhere. Legs: First tarsomere as long as the combined length of remaining four on mesothoracic and metathoracic tarsi; tibiae rounded in cross section; lateral surface of mesothoracic and metathoracic tibiae with setae and transverse rows of spine combs; metathoracic tarsomeres I–III simple; metathoracic tarsomere IV excavate, as wide as III; metathoracic tarsomere V elongate; pretarsal claws simple. Venter ( Fig. 7 ): Punctures somewhat deep, very closely dispersed; surface with recumbent, yellowish setae; hypomeron with basally opened, lateral antennal grooves; metathoracic episterna parallel sided; elytral epipleura simple, punctate; metathoracic coxal plates medially 3.0–6.0 times wider than laterally; last abdominal ventrite apically rounded.

Sexual dimorphism. Females ( Fig. 8 ) are similar to males but can be distinguished by slightly shorter antennae reaching ~1/3 of the body length; flagellomeres VI–IX slightly enlarged compared to previous antennal segments; absence of sex patches on abdominal sternites; and slightly larger and broader body with lengths of 7.0– 7.5 mm and widths of 2.0– 2.5 mm.

Aedeagus ( Fig. 9 ). Basal piece longer than wide, laterally parallel sided, dorsally opened, apically rounded; remaining parts elongate, narrow, constricted laterally just above the basal piece, laterally sinuous; parameres short, apically rounded, laterally unsclerotized; lateral tooth present midway on each lateral lobe, unsclerotized; median lobe elongate and basally broad, apically pointed, bifid, and much longer than the parameres.

Distribution. Dyscolotaxia championi is an uncommonly encountered Costa Rican species found mainly on the Caribbean side (north and east of the central mountains) of the country at lower elevations between 50–150 meters above sea level. One record (the type locality) is from a single district in the Chiriquí Province of Panama outside of Costa Rica. There is one record of D. championi from the Pacific side (south and west of the central mountains) of Costa Rica in the Osa Peninsula.

Biology. Two adults were taken from a flight intercept trap. Five adults were taken from Malaise traps placed at a single locale in the Heredia province of Costa Rica. Nearly all Costa Rican specimens were taken from a lowland moist broadleaf forest at elevations between 50– 150 m. One Osa Peninsular specimen from Rancho Quemado was taken from a transition between the northern dry broadleaf forest and the southern seasonal moist forest (Johnson, pers. com). All of these records are at a much lower elevation compared to the Bugaba record in Panama. The type location (Bugaba) is at 1000 m ( Selander and Vaurie 1962). Unlocking the mysteries of their biology, particularly their larvae, may help to clarify the status of these beetles collected in Costa Rica compared to the holotype collected in Panama. Larvae and pupae are unknown.

Note. All examined Costa Rican specimens were identified based on printed information and illustrations in Horn (1890). All Costa Rican specimens have antennal flagellomeres II–V being subequal as described and illustrated ( Figure 17a ) in Horn (1890), and as such, those specimens are currently regarded as conspecific with the type described from Panama.

Figures

Figures 5–9. Dyscolotaxia championi Horn. 5) Male, dorsal habitus. 6) Male, antenna. 7) Male, ventral habitus. 8) Female, dorsal habitus. 9) Male, aedeagus, dorsal view. (Scale: 5–9 = 1.0 mm)

Figures 14–18. Dyscolotaxia hispaniolensis Otto sp. nov., holotype (FSCA). 14) Dorsal habitus. 15) Antenna. 16) Ventral habitus. 17) Male paratype (FSCA), aedeagus, dorsal view. 18) Male paratype (FSCA), aedeagus, lateral view. (Scale: 15, 17–18 = 0.5 mm; 14, 16 = 1.0 mm)