Lacus pectinatus 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 : 12-14

Lacus pectinatus Otto, Muona and Córdoba-Alfaro , new species

Figures 23–26

Diagnosis. The new eucnemid species is distinguished from L. laticornis by the presence of broken setal patterns on the pronotum. Lacus laticornis have a more intact bands of setal patterns present on the pronotum. Punctate striae are present in the new species, whereas striae in L. laticornis is solid.

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/02/065; 15 Abril 1993; Bosque secundario” / “ HOLOTYPE:; Lacus ; pectinatus ♂; 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; Apr 2000, INBio-OET” / “ 17 Abril 2000; Bosque secundario; M/19/746” / “ ALLOTYPE:; Lacus ; pectinatus ♀; Otto, Muona & Córdoba-Alfaro; Det. R. L. Otto; 2019” (yellow printed label). Holotype and allotype are to be deposited in INBC .

Paratypes. 6 ♂♂, 3 ♀♀: COSTA RICA: Heredia Province: 1 ♂, “COSTA RICA: Heredia; Pr: La Selva Biol. Sta. ; 3 km S Pto Viejo; 10°26′N 84°01′W ” / “ 12 FEB 1993; Bosque secundario; M/00/011” / “ PARATYPE:; Lacus ; pectinatus ♂; 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/02/017; 02 Marzo 1993; Bosque secundario” / “ PARATYPE:; Lacus ; pectinatus ♂; Otto, Muona & Córdoba-Alfaro; Det. R. L. Otto; 2019” (yellow printed label) ( INBC) ; 1 ♀, “COSTA RICA: Heredia; Pr: La Selva Biol. Sta. ; 3 km S Pto Viejo; 10°26′N 84°01′W ” / “ 2 Mayo 1993; Bosque secundario; M/02/081” / “ PARATYPE:; Lacus ; pectinatus ♀; Otto, Muona & Córdoba-Alfaro; Det. R. L. Otto; 2019” (yellow printed label) ( INBC) ; 1 ♂ 1 ♀, “COSTA RICA: Prov. Heredia; Est. Biol. La Selva , 50–; 150, 10°26′N 84°01′W; 09 Marzo 2004, INBio-OET-ALAS transect” (“09 Marzo” handwritten on label) / “ 09 Marzo 2004; Malaise; M/25/777” / “ PARATYPE:; Lacus ; pectinatus ; Otto, Muona & Córdoba-Alfaro; Det. R. L. Otto; 2019” (either ♂ or ♀ printed behind species name on label) [yellow printed label] ( INBC) ; 1 ♂, “COSTA RICA: Prov. Heredia; Est. Biol. La Selva , 50–; 150, 10°26′N 84°01′W; 21 Marzo 2004, INBio-OET-ALAS transect” (“21 Marzo” handwritten on label) / “ 21 Marzo 2004; Malaise; M/23/785” / “Collection of the Global; Eucnemid Research Project; (Robert L. Otto)” (green framed white label) / “ PARATYPE:; Lacus ; pectinatus ♂; Otto , Muona & Córdoba-Alfaro ; Det. R. L. Otto ; 2019” (yellow printed label) ( GERP); Puntarenas Province : 1 ♂, “COSTA RICA. Prov. Puntarenas; Golfito Poue Nal Corcovado Est.; Agujas , Cerro Rincón. 745 m 13 FEB; 2000. A. Azofeifa. Intersección; L S 275500 522000 #56525” / “ PARATYPE:; Lacus ; pectinatus ♂; Otto, Muona & Córdoba-Alfaro, Det. J. Muona; 2022 (yellow printed label) ( INBC); PANAMA: Col ó n Province: 1 ♂, “IBISCA Project Panama ; Colon, San Lorenzo NP ; 27.3–7.3 2004” (‘27.3–7.3’ handwritten on label; black framed white label) / “IBISCA 2003-05; Morphospec. sort ; Jürgen Schmidl; COEUCN 50” (‘50’ handwritten on label; black framed white label) / “ Photo PACOEUCN ; #146” (‘146’ handwritten on label; black framed pink label) / “ PARATYPE:; Lacus ; pectinatus ♂; Otto , Muona & Córdoba-Alfaro ; Det. J. Muona; 2022” (yellow printed label) ( JMC); Panamá Province: 1 ♀, “ Panama; Canal Zone” / “ PARATYPE:; Lacus , pectinatus ♀; Otto, Muona & Córdoba-Alfaro; Det. J. Muona; 2022” (yellow printed label) ( JMC) . Paratypes are to be deposited in INBC, GERP and JMC .

Description. Male holotype: Length, 6.5 mm. Width, 2.0 mm. Body obtuse; uniformly dark brown with infuscate reddish basal margin of elytral humeri, venter reddish-brown; antennae and legs reddish-brown; head, pronotum and elytra clothed with short, recumbent yellowish setae; broken setal patterns present on the pronotum ( Figure 23 ). Head: Surface densely punctate, somewhat dullish, subspherical; frons convex, without median carina or fovea above frontoclypeal region; apical margin of frontoclypeal region rounded, about 2 times wider than base; interantennal carina absent; mandibles stout, bidentate, densely punctate. Antenna: Pectinate from flagellomeres I–VIII, attaining about 1/3the length of the body, never beyond pronotal hind angles; flagellomere I slightly longer than II; flagellomeres II–VIII each sub-equal, slightly longer than wide; rami moderately elongate, arising near apices of flagellomeres I–VIII; flagellomere IX simple, slightly longer than VIII. Pronotum: Surface somewhat dullish, densely punctate; slightly transverse, with moderate, sharp hind angles; lateral sides strongly arcuate and narrowing towards craniad; disc convex with pair of shallow circular fovea; base sinuous. Scutellar shield: Elongate, sub-triangular, setose, shallowly punctate and distally rounded. Elytra: Distinctly, shallowly punctate striate present; interstices slightly elevated; surfaces shiny, transversely rugose at humeri, dense, crowded 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 very short, excavated, slightly emarginated; metatarsomere V elongate with basally swollen, simple claws. Venter ( Figure 24 ): Closely punctate, with elongate, recumbent yellowish setae; hypomeron with basally closed, wide, lateral antennal grooves; metepisterna parallel-sided; elytral epipleura punctate; metacoxal plates medially 3.0–6.0 times wider than laterally. Aedeagus (paratype) ( Figure 25 ): Elongate, dorsally flattened, sinuate; median lobe free, short, apically rounded; parameres apically elongate, rounded, longer than median lobe, without lateral tooth; secondary lateral lobe absent; basal piece elongate, apically truncated.

Female allotype ( Figure 26 ): Length, 8.0 mm. Width, 2.5 mm. Antennae filiform, about 1/3the length of the body; flagellomere I longer than wide, slightly longer than II; flagellomere II longer than wide, much longer than III; flagellomeres III–VIII quadrate, sub-equal; left flagellomere IX missing; right antenna missing. Lateral side of elytra above epipleura infuscate reddish.

Variations. Six paratypes were examined. Several additional included paratypes from the Osa Peninsula and Panama were not examined for variations. Four male paratypes measured 6.0–7.0 mm long and 2.0 mm wide. Two female paratypes measured 5.0–7.0 mm long and 1.5–2.5 mm wide. Two of the male paratypes have the same length and width as the holotype. One male is shorter than and just as wide as the holotype. One male is longer than and just as wide as the holotype. One female is shorter and narrower than the holotype. One female is larger and wider than the holotype. All four males have a more pronounced reddish coloration along the humeri region than the remaining areas of the elytra. The reddish area of the humeri in both females are more infuscate and blended with the surrounding dark brown coloration of the elytral region. All paratypes are slightly darker than the holotype.

Distribution. This eucnemid species is known from eight specimens taken from La Selva within the province of Heredia, a single specimen each from the Puntarenas province and two sites in Panama.

Biology. Three specimens were taken from a Malaise trap. Five specimens were taken from a secondary growth forest. Larvae and pupae are unknown.

Etymology. The specific epithet is derived from the presence of pectinate antennae found in male specimens.

Figures

Figures 23–26. Lacus pectinatus sp. nov. 23) Male holotype, dorsal habitus. 24) Male holotype, ventral habitus. 25) Male aedeagus, dorsal view. 26) Female allotype, dorsal view. (Scale: 23–25 = 1.0 mm; 26 = 5.0 mm)