Laccomimus variegatus, 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 : 313-314

Laccomimus variegatus sp. n.

( Figs 61 ; 76; 86; 109; 119; 124)

Type locality. Perú, Colonia Calleria, Río Calleria, 15 km E Ecayali.

Type material. Holotype male ( USNM): dissected by us; median lobe of aedeagus and parameres included in DMHF on plastic label pinned under the holotype “ Peru, Colonia Calleria, 15 [km?] E Ecayali, muddy R. Shore, ix.10 –25.61, B. Malkin # 14” [printed white label; number “14” hw], “ HOLOTYPE Laccomimus variegatus Toledo & Michat” [red, rectangular, printed label].

Paratypes (24 exs, all bearing red, printed label “ PARATYPE Laccomimus variegatus Toledo & Michat”): Perú: same data as holotype (9 exs USNM); idem, exception made for “ ix.10 –30.61” plus “# 1” (1 ex. USNM); idem, exception made for “# 16” (1 ex. USNM); “Loreto, 80 km NE Iquitos, Explorama Lodge, 1 km up Rio Yanamono from Amazon River, 1–5.IX.1992, P. Skelley, at light / coll. Hendrich Berlin" (1 ex. ZSM). Bolivia: “Guayaramerin, Beni, river bank, Balogh, Mahunka, Zicsi”, “No. 428, beaten from vegetation, 2.Xii.1966 ” (1 ex. HNMB); “Beni, 40 km E San Borja, Estacion Biologica Beni, Estancia El Porvenir, 6–8.IX.1987, W.E. Steiner”, “At black light: open grass savanna and marsh” (8 exs USNM); “Beni, 40 km E San Borja, Estacion Biologica Beni, Palm Camp at Rio Curitaba, 13.IX.1987 / At black light, mud flat in small open area of inondation forest, W- E. Steiner" (3 exs–two of which unlabelled– USNM).

Diagnosis. Unmistakable species based on the peculiar elytral colouration, with vermiculation of irregular obscure markings and pale spots ( Fig. 61 ), unique within Laccomimus . Lobes of metacoxal processes ending in long spine in both sexes. Aedeagal features distinctive, median lobe expanded on apical fourth ( Fig. 86 a) and left paramere strongly narrowed on distal half ( Fig. 86 b).

Description. Habitus ( Fig. 61 ). TL: 2.2–2.4 mm; MW: 1.15–1.25 mm; (holotype: TL: 2.3 mm; MW: 1.2 mm); A-TL: 2.3 mm; A-MW: 1.1 mm (NUM: 16 exs); elongate, drop-shaped, strongly narrowed posteriorly. Smooth; dorsal surface with faint silky sheen.

Colour. Head testaceous, slightly darker between eyes in some specimens; pronotum testaceous with darker band along fore margin and obscure darker area close to hind margin. Elytra testaceous to reddish-brown with characteristic vermiculation of darker, obscure and irregular markings together with tiny, rounded, pale spots; these markings are concentrated mostly on disc and along lateral sides of elytra, giving illusion of very irregular, longitudinal patterns. Underside reddish-yellow to brown, paler on prosternum. Antennae and mouthparts testaceous. Legs testaceous.

Structures and sculpture. Head smooth, shiny, with fine and hard to recognise microreticulation. Pronotum smooth, with few shallow and fine punctures scattered on disc and, more numerous along inner and fore margins; microreticulation as on head; iridescence absent. Elytra elongate with pronounced subapical sinuation; surface shiny, faintly iridescent; microreticulation fine, poorly impressed; small, shallow, irregular grooves visible together with fine scattered punctures. Underside shiny, with hardly visible silky sheen. Prosternal process broad, slightly elevated, obtuse at tip. Lobes of metacoxal processes ending in long sharp spine in both sexes.

Male. Last abdominal ventrite tectiform, lateral sides almost rectilinear. Outer claw of forelegs scimitar-shaped ( Fig. 76 ). Median lobe of aedeagus, in left lateral view ( Fig. 86 a), widely arched, slender but robust, expanded on apical fourth, then narrowed into subtruncate tip. In dorsal view ( Fig. 109 ), sinuate on both sides, with visible constriction on distal third of left side; apex with narrow tip turned to left; ejaculator groove almost uniformly wide up to apex. Left paramere ( Fig. 86 b) regularly rounded along ventral side, strongly narrowed beyond basal half on dorsal side.

Female. Not duller than male. Last abdominal ventrite elongate, with fore margin broadly rounded. Lateral tergites thin, partly membranous. Gonocoxal blade ( Fig. 119 a) with single medial denticle; ramus ( Fig. 119 b) with large and spaced dentation; first tooth, following apical hook, as developed as second tooth.

Distribution. Bolivia, Perú ( Fig. 124 ).

Etymology. The specific epithet is an adjective in the nominative singular and refers to the distinctive elytral colouration, unique within this genus.

Notes on variability. All but one specimens from Bolivia (all immature) bear obscure markings on the elytra, very difficult to see, colouration appearing uniform. This might also depend on the way the beetles have been killed and preserved.

Remarks. This species is very close to L. amazonas and L. spinosus , but readily recognisable by the peculiar elytral colouration. These three species form a distinct group within Laccomimus , characterised by the following combination of peculiar characters: prosternum protruding anteriorly, almost bulbous ( Figs 24–26 ); prosternal process very broad and short, saddle shaped in lateral view, barely reaching metaventrite and positioned below its level ( Figs 24–26 ); lobes of metacoxal processes ending in long sharp spine in both sexes ( Fig. 38 ).

Figures

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 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 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 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.

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 26 – 31. SEMs of head, prosternum and prosternal process in Laccomimus species: 26) L. amazonas (male), oblique lateral view; 27) idem, at higher magnification; 28) L. alvarengi (female) ventral view; 29) L. bordoni (female), ventral view; 30) idem, oblique lateral view; 31) idem, at higher magnification.

FIGURES 38 – 43. SEMs of Laccomimus species, ventral view. 38 – 41) metacoxal processes: 38) L. amazonas (male); 39) L. alvarengi (female); 40) L. bordoni (female); 41) L. bolivari (female); 42 – 43) abdomen on L. bordoni, showing sexual difference in last ventrite: 42) male (arrow indicates slightly sinuate caudal margins); 43) female.