Adelothyreus totus 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 : 9-10

Adelothyreus totus Otto, Muona and Córdoba-Alfaro , new species

Figures 17–19

Diagnosis. A complete lateral pronotal ridge will distinguish the new species from all known Adelothyreus species present in Costa Rica.

Type material. Male holotype: “ COSTA RICA: Heredia pr.; La Selva Bio. Sta.; 3 km S Pto. Viejo ; 10°26′N 84°01′W ” / “I. IV.1988; H.A. Hespenheide ” (“I”, “IV” and “8” handwritten) / “ HOLOTYPE:; Adelothyreus ; totus ♂; Otto, Muona & Córdoba-Alfaro; Det. R. L. Otto; 2021” (red printed label). Holotype to be deposited in INBC.

Description. Male holotype: Length, 3.0 mm. Width, 0.75 mm. Body elongate; uniformly dark black; antennae dark brownish black; legs dark brown; head, pronotum and elytra clothed with short, recumbent yellowish setae ( Figure 17 ). Head: Surface densely punctate, somewhat dullish, subspherical; frons convex, without median fovea or carina; apical margin of frontoclypeal region rounded, more than 2.0 times wider than base; mandibles stout, bidentate, densely punctate. Antenna: Pectinate from flagellomeres III–VIII, attaining about 3/4 the length of the body; flagellomere I longer than II; flagellomere II strongly, asymmetrically serrate; flagellomere III longer than wide, shorter than IV; flagellomeres IV–VIII each sub-equal, longer than wide; flagellomere IX longer than VIII; rami on flagellomeres III–VIII arising at apical end, elongate and about 2.0 times longer than length of segment. Pronotum: Surface somewhat dullish, closely punctate; longer than wide, with poorly developed hind angles; lateral sides parallel-sided, apically arcuate; disc flattened with delicate median groove; anterior lateral pronotal ridge completely connected to the posterior lateral pronotal ridge forming a complete lateral ridge ( Figure 18 ); base sinuous, strongly impressed above scutellar shield. Scutellar shield: Short, transverse, shallowly punctate, setose and distally truncated. Elytra: Shallow striate indicated at humeri, indistinct elsewhere; interstices flattened; surfaces shiny, closely punctate to rugose at basal 1/2, shallowly punctate at apical 1/2. 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 very short, excavate; metatarsomere V short with simple claws. Venter ( Figure 19 ): Closely punctate, with short, recumbent yellowish setae; hypomeron with apically widened notosternal antennal grooves; antennal grooves apically punctate, basally smooth; metepisterna caudally wide; elytral epipleura punctate; metacoxal plates parallel-sided.

Distribution. This eucnemid species is only known from its type location in Costa Rica.

Biology. No biological information is known for the new species. Larvae and pupae are unknown.

Etymology. The specific epithet is derived from ‘totus’, a Latin adjectival word for complete due to the presence of a complete lateral pronotal ridge.

Figures

Figures 17–22. Costa Rican Eucnemidae. 17) Adelothyreus totus sp. nov., dorsal habitus. 18) Adelothyreus totus sp. nov., pronotal lateral habitus. 19) Adelothyreus totus sp. nov., ventral habitus. 20) Quirsfeldia stethonoides sp. nov., dorsal habitus. 21) Quirsfeldia stethonoides sp. nov., pronotal lateral habitus. 22) Quirsfeldia stethonoides sp. nov., ventral habitus. (Scale: 17–22 = 1.0 mm)