Deltometopus bicolor 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 : 30-31

Deltometopus bicolor Otto, Muona and Córdoba-Alfaro , new species

Figures 64–66

Diagnosis. The new eucnemid species is very similar to D. fastidiosus Bonvouloir. Deltometopus bicolor can be distinguished from D. fastidiosus by the presence of interrupted interantennal carina at the base of the frontoclypeal region. Dromaeolus fastidiosus have a complete interantennal carina.The new species is further distinguished from D. foveolatus by its elongate, less cuneiform habitus and absence of sulcus along lateral margin of the pronotum.

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/13/028; 03 Marzo 1993; Bosque secundario” / “ HOLOTYPE:; Deltometopus ; bicolor ♂; Otto, Muona & Córdoba-Alfaro; Det. R. L. Otto; 2019” (red printed label). Female allotype: “ COSTA RICA, Heredia; Est.Bio. La Selva , 50–; 150 m, 10°26′N 84°01′W; Proy. ALAS, INBio-OET” / “M/13/028; 03 Marzo 1993; Bosque secundario” / “ ALLOTYPE:; Deltometopus ; bicolor ♀; Otto, Muona & Córdoba-Alfaro; Det. R. L. Otto; 2019” (yellow printed label). Holotype and allotype are to be deposited in INBC .

Paratypes. 2 ♂♂, 1 ♀: COSTA RICA: 1 ♂, “COSTA RICA: Heredia; Est.Bio. La Selva , 50–; 150 m 10°26′N 84°01′W; Proy. ALAS, INBio-OET” / “M/09/072; 15 Abril 1993; Bosque secundario” / “ PARATYPE:; Deltometopus ; bicolor ♂; 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/11/341; 15 Febrero 1994; Bosque secundario” / “Collection of the Global; Eucnemid Research Project; (Robert L. Otto)” (green framed white label) / “ PARATYPE:; Deltometopus ; bicolor ♂; 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/02/400; 17 Julio 1995; Bosque secundario” / “ PARATYPE:; Deltometopus ; bicolor ♀; 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, 2.5 mm. Width, 1.0 mm. Body elongate; dark black; antennae brown; femur and tibiae brown, tarsi brown; head, pronotum and elytra clothed with short, recumbent whitish setae ( Figure 64 ). Head: Surface densely punctate, somewhat shiny, subspherical; frons convex, without fovea or ridge; apical margin of frontoclypeal region rounded, more than 2 times wider than base; interantennal carina incomplete; mandibles stout, bidentate, densely punctate. Antenna: Serriform from flagellomeres I–VIII, attaining about 1/3 the length of the body, just beyond pronotal hind angles; flagellomere I longer than II; flagellomeres II–III sub-equal, slightly longer than wide; flagellomeres IV–VIII sub-equal, each slightly larger than III, slightly longer than wide; flagellomere IX simple, slightly longer than VIII. Pronotum: Surface somewhat shiny, densely punctate; quadrate, with moderate, sharp hind angles; lateral sides sinuous, apically narrowed, arcuate; disc convex without fovea or ridge; base sinuous. Scutellar shield: Transverse, sub-triangular, shallowly punctate and distally rounded. Elytra: Striae delicately indicated on humeri, indistinct elsewhere; interstices flattened; surfaces shiny, transversely rugose at basal 1/4, dense, crowded, shallow punctures present 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 short, excavate-emarginate; metatarsomere V elongate with simple claws. Venter ( Figure 65 ): Closely punctate, with short, recumbent white-colored setae; hypomeron with basally widened, 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 66 ): Length, 4.0 mm. Width, 1.0 mm. Flagellomeres serriform, about 1/3the length of the body; flagellomere I longer than wide, longer than II; flagellomere II–IV sub-equal, quadrate; flagellomeres V–VIII each slightly longer than IV, quadrate, sub-equal. Frons impressed above frontoclypeal region.

Variations. Three paratypes were examined. Two male paratypes measured 3.0 mm long and 1.0 mm wide. One female paratype measured 4.0 mm long and 1.0 mm wide. All paratypes are longer than and just as wide as the holotype. Both male paratypes have a more pronounced impression on the frons just above the frontoclypeal region. Frons on the female paratype are simple, without any indications of impression above the frontoclypeal region. Pedicel and flagellomere I are yellowish in one male paratype. The remaining two paratypes have antennal colorations similar to the holotype. Habitus in all paratypes are just as dark as the holotype. Striae at the humeri are more pronounced in one of the male and female paratypes compared to the holotype. Striae in the other male paratype are similar to the holotype.

Distribution. This eucnemid species is known from five specimens taken from a single location in four different collection events at La Selva within the province of Heredia.

Biology. All specimens in the type series were taken from a second growth forest. Larvae and pupae are unknown.

Etymology. The specific epithet is derived from its black habitus along with dark brown legs and antennae.

Tribe Nematodini Leiler, 1976

Diagnosis. Mandibles short, with ventral secondary tooth, without expanded lateral surfaces; prothoracic tibiae with one apical spur; male prothoracic tarsomere I with basal sex combs; tarsomere IV usually bilobed; lateral sides of mesothoracic and metathoracic tibiae variable, either with setae and simple spines or with setae and transverse rows of spine combs; hypomeron with or without antennal grooves; prothoracic sternal peg high, either truncated or excavated; median lobe without dorsal basal struts, fused with lateral lobes, distinct, with narrowly and deeply bifurcate apex; bursa divided, simple; spermatheca sclerotized, divided and U-shaped ( Muona 1993; Otto 2017c).

Figures

Figures 63–66. Costa Rican Deltometopus species. 63) Deltometopus foveolatus, dorsal habitus. 64) Deltometopus bicolor sp. nov., male holotype, dorsal habitus. 65) Deltometopus bicolor sp. nov., male holotype, ventral habitus. 66) Deltometopus bicolor sp. nov., female allotype, dorsal habitus. (Scale: 63–66 = 1.0 mm)