Onichodon confluentus Otto, Muona and Córdoba-Alfaro, 2023

Otto, Robert L., Muona, Jyrki & Córdoba-Alfaro, Jim, 2023, A new genus and sixteen new species of false click beetles (Coleoptera: Eucnemidae) described from the Heredia Province of Costa Rica with several additional records from the Osa Peninsula and Panama, Insecta Mundi 2023 (991), pp. 1-36 : 16-17

Onichodon confluentus Otto, Muona and Córdoba-Alfaro , new species

Figures 30–32

Diagnosis. The new eucnemid species can be readily distinguished by the presence of confluent surfaces of the frons from any members of Fornax and Onichodon present in Costa Rica.

Type material. Male holotype: “ COSTA RICA: Heredia; Est.Bio. La Selva, 50–; 150 m 10°26′N 84°01′W; Proy. ALAS, INBio-OET” / “M/15/121; 02 Junio 1993; Bosque secundario” / “ HOLOTYPE:; Onichodon ; confluentus ♂; Otto, Muona & Córdoba-Alfaro’ Det. R. L. Otto; 2019” (red printed label). Female allotype: “ COSTA RICA: Prov. Heredia:; 16 km SSE La Virgen, 1050–; 1150 m, 10°16′N 84°05′W; 9 Abril 2001; INBio-OET-ALAS transect” (“9 Abril”, “1” were handwritten on label) / “ 09 Abril 2001; 11/M/01/061; Transect” / “ ALLOTYPE:; Onichodon ; confluentus ♀; Otto, Muona & Córdoba-Alfaro; Det. R. L. Otto; 2019” (yellow printed label). Holotype and allotype are to be deposited in INBC .

Paratypes. 7 ♂♂: COSTA RICA: 1 ♂, “COSTA RICA: Heredia; Est.Bio. La Selva, 50–; 150 m 10°26′N 84°01′W; Proy. ALAS, INBio-OET” / “M/14/061; 02 Abril 1993; Bosque secundario” / “ PARATYPE:; Onichodon ; confluentus ♂; Otto, Muona & Córdoba-Alfaro; Det. R.L. Otto; 2019” (yellow printed label) ( INBC); 1 ♂, “COSTA RICA: Heredia; Est.Bio. La Selva, 50–; 150 m 10°26′N 84°01′W; Proy. ALAS, INBio-OET” / “M/15/094; 03 Mayo 1993; Bosque secundario” / “ PARATYPE:; Onichodon ; confluentus ♂; Otto, Muona & Córdoba-Alfaro; Det. R.L. Otto; 2019” (yellow printed label) ( INBC); 1 ♂, “COSTA RICA: Heredia; Est.Bio. La Selva, 50–; 150 m 10°26′N 84°01′W; Proy. ALAS, INBio-OET” / “M/16/122; 02 Junio 1993; Bosque secundario” / “Collection of the Global; Eucnemid Research Project; (Robert L. Otto)” (green framed white label) / “ PARATYPE:; Onichodon ; confluentus ♂; Otto, Muona & Córdoba-Alfaro; Det. R.L. Otto; 2019” (yellow printed label) ( GERP); 1 ♂, “COSTA RICA: Heredia; Est.Bio. La Selva, 50–; 150 m 10°26′N 84°01′W; Proy. ALAS, INBio-OET” / “M/14/148; 01 Julio 1993; Bosque secundario” / “ PARATYPE:; Onichodon ; confluentus ♂; Otto, Muona & Córdoba-Alfaro; Det. R.L. Otto; 2019” (yellow printed label) ( INBC); 1 ♂, “COSTA RICA: Heredia; Est.Bio. La Selva, 50–; 150 m 10°26′N 84°01′W; Proy. ALAS, INBio-OET” / “M/12/397; 30 Junio 1995; Bosque primario” / “ PARATYPE:; Onichodon ; confluentus ♂; Otto, Muona & Córdoba-Alfaro; Det. R.L. Otto; 2019” (yellow printed label) ( INBC); 1 ♂, “COSTA RICA: Heredia; Est.Bio. La Selva, 50–; 150 m 10°26′N 84°01′W; Proy. ALAS, INBio-OET” / “M/05/655; 31 Mayo 1996; Bosque primario” / “ PARATYPE:; Onichodon ; confluentus ♂; Otto, Muona & Córdoba-Alfaro; Det. R.L. Otto; 2019” (yellow printed label) ( INBC); 1 ♂, “ 21 Mar 2001; INBio-OET-ALAS transect; COSTA RICA: Prov. Heredia:; 16 km SSE La Virgen, 1050–; 1150 m, 10°16′N 84°05′W (“21 Mar” and “1” were handwritten on label) / 21 Marzo 2001; Transect; 11/M/07/067” / “ PARATYPE:; Onichodon ; confluentus ♂; Otto, Muona & Córdoba-Alfaro; Det. R.L. Otto; 2019” (yellow printed label) ( INBC). Paratypes are to be deposited in INBC and GERP.

Description. Male holotype: Length, 8.0 mm. Width, 2.5 mm. Body elongate; dark reddish-brown; antennae and legs dark reddish-brown; head, pronotum and elytra clothed with short, recumbent yellowish setae ( Figure 30 ). Head: Surface dullish, subspherical, confluently rugose; frons convex, simple without impression or carina; apical margin of frontoclypeal region weakly trilobed, about 2 times wider than base; mandibles stout, bidentate, densely punctate. Antenna: Filiform from flagellomeres I–IX, attaining at least 1/3 the length of the body, just beyond pronotal hind angles; flagellomere I longer than wide, slightly longer than II; flagellomeres II–VIII each longer than wide, sub-equal; flagellomere IX slightly longer than VIII. Pronotum: Surface somewhat shiny, with closely spaced punctures; quadrate, with well-developed, sharp hind angles; sides subparallel-sided at basal 1/2, arcuate at apical 1/2, slightly sinuate above pronotal hind angles; disc convex with shallow fovea above scutellar shield; base sinuous, with circular pit on each side above scutellar shield. Scutellar shield: Longer than wide, sub-triangular, shallowly punctate, setose and distally rounded. Elytra: Very shallow striae indicated; interstices slightly elevated; surfaces shiny, transversely rugose at basal 1/4, closely punctate elsewhere. Legs: First tarsomere as long as the combined lengths of the remaining four on meso- and metatarsi; tibiae rounded in cross section; metatarsomeres I–III simple; metatarsomere IV excavated; metatarsomere V elongate with basally toothed claws. Venter ( Figure 31 ): Closely punctate, with short, recumbent yellowish setae; hypomeron with basally opened, lateral antennal grooves; metepisterna parallel-sided; elytral epipleura punctate; metacoxal plates medially 3.0–6.0 times wider than laterally.

Female allotype ( Figure 32 ): Length, 12.0 mm. Width, 4.0 mm. Antennae weakly and asymmetrically serriform, about 1/3 the length of the body; flagellomere I longer than wide, slightly longer than II; flagellomere II slightly longer than wide, shorter than III; flagellomeres III–VIII longer than wide, sub-equal.

Variations. Seven male paratypes measured 6.0– 10.5 mm long and 1.5–2.5 mm wide. Two male paratypes are larger than and just as wide as the holotype. The remaining five paratypes are shorter and narrower than the holotype. Pronotal punctures are widely dispersed in one paratype, whereas the remaining six paratypes have exoskeletal structures similar to the holotype.

Distribution. This eucnemid species is known from nine specimens taken from two locations within the province of Heredia.

Biology. Two specimens were taken from a primary forest. Five specimens, including the holotype were taken from a second growth forest. Larvae and pupae are unknown.

Etymology. The specific epithet is named from the presence of confluent surfaces of the frons on the new species.

Figures

Figures 27–30. Costa Rican macraulacine eucnemids. 27) Maelodrus costaricensis sp. nov., dorsal habitus. 28) Maelodrus costaricensis sp. nov., lateral habitus. 29) Maelodrus costaricensis sp. nov., ventral habitus. 30) Onichodon confluentus sp. nov., male holotype, dorsal habitus. (Scale: 27–29 = 1.0 mm; 30 = 5.0 mm)

Figures 31–34. Costa Rican macraulacine eucnemids. 31) Onichodon confluentus sp. nov., male holotype, ventral habitus. 32) Onichodon confluentus sp. nov., female allotype, dorsal habitus. 33) Onichodon rufus sp. nov., dorsal habitus. 34) Onichodon rufus sp. nov., ventral habitus. (Scale: 31–32 = 5.0 mm; 33–34 = 1.0 mm)