Lachnopus serraticrus, Poinar & Legalov, 2017

Poinar, GO & Legalov, AA, 2017, Five new species from the subfamily Entiminae (Coleoptera: Curculionidae) in Dominican amber, Palaeontologia Electronica 20 (2), pp. 1-13 : 3-6

Lachnopus serraticrus sp. nov.

Figures 3-6

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Holotype. Deposited in Poinar amber collection maintained at Oregon State University, Corvallis (Oregon, USA) (accession # 14).

Description. The specimen is complete. Body length (without rostrum), 7.5 mm; rostrum length, 1.4 mm. Body black, with glabrous, small, subcircular, and appressed scales.

Head 0.4x as long as rostrum, not constricted behind eye; rostrum weakly curved, short, 0.7x as long as pronotum, finely punctate; lateral margins of rostrum narrowing to eyes; epistoma indistinct; forehead quite narrow, flattened; eyes large, convex, rounded; temples quite short, 0.4x as long as eye; antennal scrobes directed under eye but not reaching eye; pterygia dorso-lateral; geniculate antennae long, inserted in apical third of rostrum, reaching base of elytra; antennomeres almost conical; 1st antennomere (scape) 7.1x longer than wide, reaching base of eye; 2nd antennomere 1.7x longer than wide, 0.2x as long as and 0.6x as narrow as 1st antennomere; 3rd antennomere 2.4x longer than wide, 1.2x as long as and 0.8x as narrow as 2nd antennomere; 4th antennomere 2.0x longer than wide, 0.8x as long as and equal in width to 3rd antennomere; 6th antennomere 2.5x longer than wide; 7th antennomere 2.0x longer than wide, 1.2x as long as and 1.5x as wide as 6th antennomere; 8th antennomere 1.3x longer than wide, 0.8x as long as and 1.3x as narrow as 7th antennomere; club compact, 3.0x longer than wide, 0.3x as long as flagellum, with fused articles.

Pronotum wide, trapezoidal, 1.7x longer than width at apex, 0.8x longer than wide in middle, 0.6x longer than wide at base; densely punctate, weakly flattened, 0.8x as narrow as elytral base; sides almost straight; scutellum trapezoidal.

Elytra convex, 3.3x as long as pronotum, 1.7x longer than wide at base and in middle, 2.4x longer than wide at apical fourth; humeri weakly convex; punctate striae distinct, with large points; intervals weakly convex, 1.2–1.5x as wide as diameter of points; apical part of elytra convex laterally.

Prosternum weakly convex, densely punctate, without postorbital lobe and vibrissae; precoxal portion of prosternum 0.3x as long as procoxal cavities and 0.6x as long as postcoxal portion; postcoxal portion of sternum 1.6x as long as precoxal portion and 0.5x as long as procoxal cavities; procoxal cavities connect; metasternum convex, punctate; metepisternum quite narrow.

Abdomen convex, densely punctate; 1st, 2nd and 5th ventrites elongate; 1st ventrite 2.0x as long as metacoxal cavities length; 2nd ventrite subequal to 1st ventrite; 3rd and 4th ventrites short, equal in length; 3rd ventrite 0.4x as long as 2nd ventrite; 5th ventrite 2.0x as long as 4th ventrite.

Procoxae located near middle of prosternum, closer to anterior margin; mesocoxae rounded, narrowly separated; femora thickened, punctate, without teeth; profemora 4.8x longer than wide in middle; metafemora 4.7x longer than wide in middle; tibiae weakly curved, punctate, serrated on inner margin, with mucro; metatibial corbel enclosed, without scales; protibia 6.9x longer than wide in middle; metatibia 7.5x longer than wide in middle; tarsi elongate; 1st and 2nd tarsomeres conical; 3rd tarsomere bilobed; 5th tarsomere elongate; claws free; protarsi: 1st tarsomere 1.6x longer than wide; 2nd tarsomere 1.3x longer than wide, subequal in length, 1.2x as wide as 1st tarsomere; 3rd tarsomere 0.6x longer than wide, equal in length and 2.2x as wide as 2nd tarsomere; 5th tarsomere 3.8x longer than wide, 1.9x as long as and 0.3x as narrow as 3rd tarsomere; metatarsi: 2nd tarsomere 0.8x as long as 1st tarsomere; 3rd tarsomere 0.8x as long as 2nd tarsomere; 5th tarsomere 4.3x longer than wide, 1.6x as long as 3rd tarsomere.

Type locality. Amber mine in the northern portion of the Dominican Republic.

Etymology. The species epithet is from the Latin “serratus” = toothed and the Latin “crusis” = leg, in reference to the serrated tibiae.

Diagnosis. The new species is very close to Lachnopus acuticollis ( Gyllenhal, 1834) from Cuba but differs by the much smaller body size, narrower elytral intervals, and scape reaching only to the middle of the eye. From L. proteus ( Olivier, 1807) from Hispaniola, it differs by having all tibiae serrated on the inner margins, the trapezoidal pronotum, evenly convex eyes, procoxa located further from front margin of prosternum and the apical part of the elytra convex laterally.

Remarks. This species belongs to the tribe Eustylini because the elytra have humeri, the metabibial corbel are enclosed, the claws are free, and the pterygia are dorso-lateral. The front margin of prosternum without vibrissae, trapezoid pronotum, base of elytra slightly wider than pronotum, lateral margins of the rostrum narrowed toward the eyes, and the procoxae located closer to the front margin of the prosternum are diagnostic characters of the genus Lachnopus .

Figures

FIGURE 3. Drawing of pronotum and elytra of Lachnopus serraticrus n. sp. in dorsal view. Scale bar equals 1.4 mm.

FIGURE 4. Lateral view of Lachnopus serraticrus n. sp. in Dominican amber. Scale bar equals 1.3 mm.

FIGURE 5. Drawing of Lachnopus serraticrus n. sp. in lateral view. Scale bar equals 1.1 mm.

FIGURE 6. Lateral view of protibiae of Lachnopus serraticrus n. sp. in Dominican amber. Scale bar equals 0.4 mm.