Laccomimus malkini, Toledo, Mario & Michat, Mariano C., 2015

Toledo, Mario & Michat, Mariano C., 2015, Description of Laccomimus gen. n. and eleven new species from the Neotropical region (Coleoptera, Dytiscidae, Laccophilinae), Zootaxa 3990 (3), pp. 301-354 : 312-313

Laccomimus malkini sp. n.

( Figs 9 ; 23; 37; 60; 71; 85; 108; 117; 123; 135)

Type locality. Colombia, Amazonas , Leticia.

Type material. Holotype male ( USNM): with genitalia dissected probably by Young; median lobe of aedeagus and parameres included in DMHF on plastic label pinned under the holotype “ Colombia, Amaz. [= Amazonas ], Leticia, III.12 –15.1969, P. & P. Spangler” [printed], “ HOLOTYPE Laccomimus malkini Toledo & Michat” [red, rectangular, printed label].

Paratypes (68 exs, all bearing red, printed label “ PARATYPE Laccomimus malkini Toledo & Michat”): Colombia: same data as holotype (28 exs USNM, MTP). Bolivia: “Beni, 40 km E San Borja, Estacion Biologica Beni, Estancia El Polvenir, 6–8.IX.1987, W.E. Steiner”, “At black light: open grass savanna and marsh” (2 exs USNM). Brazil: “Sao Paulo, Piracicaba, blacklight, 12.II.1966, C.A. Triplehorn” (4 exs USNM); “Para, Belem, 10. VII.1969, P. & P. Spangler” (1 ex. USNM). Ecuador: “Napo, Lago Agrio (2 km N), 26.IX.1975, Andrea Langley” (3 exs USNM); idem except for “ 16.VIII.1975, blacklight” (1 ex. USNM). Paraguay: “Jejuí-Mí, light trap, 19.XII.2003, leg. M.C. Michat” (5 exs MCMC); idem “ 20.XII.2003 ” (2 exs MCMC). Perú: “Madre de Dios, Rio Tambopata Res, 30 air km SW Pto-Maldonado, 290 m, 2–5.XI.1979, J.B. Heppner, subtropical moist forest” (8 exs USNM). Suriname: “Langaman, Kondre-Marowijne distr., 25.X.1963, Borys Malkin” (5 exs USNM); “Zanderijsavanne, 1st tributary of Colakreek, 55°14'W, 05°27'N, 4.IX.1969, leg N. Nieser (SN 114)” (1 ex. NMW); “Paramaribo, Guest House of Museum, at light, 20.VIII–23.IX.1969, leg N. Nieser” (2 exs NMW). Venezuela: “Guarico, 12 km S Calabozo, II.6 –12.1969, P. & P. Spangler” (3 exs USNM); idem “ 15 km S Calabozo, II.9 – 13.1969” (1 ex. USNM); “Bolivar State, 04°41.878'N, 61°04.246'W, 815 m, Gran Sabana, N Santa Elena, marshy area long Rt. 10, 17. VII.2010, leg. Short, Tellez & Camacho, VZ10-0717-03A” (4 exs VAIP – each specimen with additional label KUNHM-ENT, with its own barcode and catalogue number).

Diagnosis. Easily recognised by the combination of (usually) uniformly brown elytra and bright pale pronotum, along with male (scimitar-shaped outer foreclaw, characteristic bisinuate left paramere) and female (two-toothed gonocoxal blades) characters.

Description. Habitus ( Fig. 60 ). TL: 2.0– 2.3 mm; MW: 1.0– 1.2 mm (holotype: TL: 2.05 mm; MW: 1.1 mm); A-TL: 2.1 mm; A-MW: 1.2 mm (NUM: 36 exs); almost regularly oval, gradually narrowed backward; elytral tip almost truncate. Glossy to almost dull; iridescence on elytra more or less visible.

Colour. Head chestnut brown, gradually paler on front and clypeus; pronotum testaceous, with darker band along hind margin. Elytra uniformly chestnut brown, rarely with more or less defined paler markings on subbasal and preapical position. Underside yellowish, at most slightly darkened on sutures. Antennae and mouthparts testaceous. Legs testaceous, metatarsi slightly darker.

Structures and sculpture. Head smooth, shiny, with quite impressed microreticulation of rounded cells. Pronotum shiny, often with slight iridescence. Few scattered punctures only along sides. Elytra with no or hardly visible subapical sinuation; shiny to almost dull, with iridescence of variable intensity; microreticulation quite impressed, accompanied by subtle scratches and scattered, poorly visible punctures. Prosternal process ( Fig. 23 ) rounded at tip, slightly elevated. Lobes of metacoxal processes regularly rounded in both sexes ( Fig. 37 ).

Male. Last abdominal ventrite tectiform, with antero-lateral sides visibly sinuate. Outer claw of forelegs scimitar-shaped ( Fig. 71 ). Median lobe of aedeagus, in left lateral view ( Fig. 85 a), slender; base and distal portion forming an angle of about 160°; distal portion straight, gradually narrowed to apex, ending in small button-like expansion, quite variable in shape. In dorsal view ( Fig. 108 ) slender and acuminate, gradually tapering from base to tip; dorsal lamina strongly sinuate close to base; ejaculator groove narrow. Left paramere ( Fig. 85 c) straight, visibly bi-sinuate on ventral side.

Female. Elytra and pronotum often slightly duller than in males. Last abdominal ventrite triangular, narrowly rounded at apex. Lateral tergites similar to L. distinctus : wide and sclerotized. Gonocoxal blades ( Fig. 117 a) with second denticle at about distal 4/5. Ramus also distinctive ( Fig. 117 b), with numerous densely distributed small teeth of uniform size.

Distribution. Bolivia, Brazil, Colombia, Ecuador, Paraguay, Perú, Suriname, Venezuela ( Fig. 123 ).

Habitat. In Santa Elena ( Venezuela) some specimens were collected in a marshy area exposed to direct sunlight (Fig. 135).

Etymology. Name given in litteris by Frank N. Young and Paul J. Spangler, in honour of the collector Borys Malkin (cf. Young 1974: 2, 3). The specific epithet is a noun in the genitive case.

Notes on variability. Specimens from most localities have uniformly brown elytra. Paler markings, variably developed but never sharply defined, have been observed in most specimens from Paraguay. The few exemplars seen from Brazil (Piracicaba) share peculiar characters: larger size (TL: 2.4–2.5 mm; MW: 1.2–1.25 mm), more elongate body shape (with apical sinuation of elytra missing or almost so), pale patterns on the elytra well developed and clear ( Fig. 60 b), and a button-like apical expansion of the median lobe projecting posteriorly into a small, acute process ( Fig. 85 e). Such specimens might represent a distinct species, but at present this is difficult to determine due to the few available specimens.

Remarks. This species is close to L. pumilio and related species (see below), sharing with them a series of characters: scimitar-shaped male outer foreclaws, the lobes of the metacoxal processes rounded in both sexes, and the prosternal process broad and short, barely reaching the metaventrite. However, it is one of only two species, along with L. distinctus , that exhibits female gonocoxal blades with two teeth. The peculiar ramus, bearing dense, numerous and uniformly small teeth, is unique within the genus.

Figures

FIGURES 8 – 13. SEMs of Laccomimus species, ventral view: 8) L. distinctus (male); 9) L. malkini (female); 10) L. amazonas (male); 11) L. alvarengi (female); 12) L. bordoni (male); 13) L. bolivari (female).

FIGURES 59 – 66. Subschematic body shape and colour patterns in Laccomimus species: 59) L. distinctus; 60) L. malkini, a) typical specimen from Colombia, b) specimen from Piracicaba, Brazil; 61) L. variegatus (Perú); 62) L. amazonas; 63) L. pumilio (Florida, USA); 64) L. alvarengi, a – b) variation in colouration patterns; 65) L. bordoni; 66) L. spangleri.

FIGURES 20 – 25. SEMs of head, prosternum and prosternal process in Laccomimus species: 20) L. distinctus (male), ventral view, 21) idem, at higher magnification; 22) idem, oblique lateral view; 23) L. malkini (female) ventral view; 24) L. amazonas (male), ventral view (arrow indicates protruding prosternum); 25) idem, at higher magnification.

FIGURES 32 – 37. SEMs of metacoxal processes in Laccomimus species, ventral view: 32) L. distinctus (male); 33 – 36) L. distinctus (females), variability in development of apical angulation in different specimens; 37) L. malkini (female).

FIGURES 67 – 83. Prosternal process and claws in Laccomimus species. 67 – 69) P rosternal process: 67) L. pumilio (Florida, USA); 68) L. pumilio (Cuba); 69) L. alvarengi (Perú). 70 – 83) M ale left protarsal claws: 70) L. bordoni (Paraguay); 71) L. malkini (Madre de Dios, Perú); 72) L. spangleri (holotype); 73) L. distinctus (holotype); 74) L. bolivari (Trinidad); 75) L. amazonas (holotype); 76) L. variegatus (Colonia Calleria, Perú); 77) L. alvarengi (holotype); 78) L. alvarengi (Loreto, Perú); 79) L. alvarengi (Guayaramerin, Bolivia); 80) L. alvarengi (Esmeraldas, Ecuador); 81) L. alvarengi (Albrook, Panamá); 82) L. pumilio (Cayo District, Belize); 83) L. pumilio (Cayamas, Cuba).

FIGURES 84 – 87. Male genitalia in Laccomimus species, left lateral view: 84) L. distinctus, a) median lobe, b) left paramere, c) right paramere; 85) L. malkini (Loreto, Perú), a) median lobe, b) magnification of apex of median lobe, c) left paramere, d) right paramere, e) magnification of apex of median lobe (specimen from Piracicaba, Brazil); 86) L. variegatus, a) median lobe, b) left paramere, c) right paramere; 87) L. spinosus, a) median lobe, b) left paramere.

FIGURES 107 – 115. Median lobe of aedeagus in Laccomimus species, dorsal view: 107) L. distinctus; 108) L. malkini; 109) L. variegatus; 110) L. amazonas; 111) L. alvarengi; 112) L. improvidus; 113) L. bordoni; 114) L. spangleri; 115) L. bolivari.

FIGURES 116 – 121. Female genitalia and cladogram. 116 – 120) Female genitalia in Laccomimus species, left lateral view: 116) L. distinctus (Paraguay), a) left gonocoxa, b) ramus; 117) L. malkini (Perú), a) left gonocoxa, b) ramus; 118) L. alvarengi (Brazil), a) left gonocoxa, b) ramus; 119) L. variegatus (Perú), a) left gonocoxa, b) ramus; 120) L. bordoni (Bolivia), ramus (arrow indicates lateral proximal process of ramus). 121) Single most parsimonious cladogram rooted between ingroup and outgroup, with character changes mapped for each clade. Solid rectangles indicate unique character state transformations; open rectangles indicate homoplasious character state transformations. Support values are indicated on each branch as Bremer / Bootstrap.

FIGURES 122 – 125. Distribution maps of Laccomimus species: 122) L. distinctus; 123) L. malkini; 124) L. variegatus (open circles), L. spinosus (single pentagon in Brazil), L. amazonas (single star in Venezuela); 125) L. alvarengi in South America.