Laccomimus improvidus, 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 : 319-320

Laccomimus improvidus sp. n.

( Figs 89 ; 112; 129; 133)

Type locality. Venezuela, Guarico State, 8°31.705'N, 66°22.602'W, 145 m, ca. 65 km S Las Mercedes, large lagoon with vegetation.

Type material. Holotype male ( MIZA): dissected by us; last two metaventrites and genitaia included in DMHF on plastic label, pinned under the holotype “Guarico State, 8°31.705'N, 66°22.602'W, 145 m, ca. 65 km S Las Mercedes, large lagoon with vegetation, 9.I.2009, leg. Short, Miller, Garcia & Camacho, VZ09-0109- 01X ” [printed], “ KUNHM-ENT SM0845078” [printed, together with barcode], “ HOLOTYPE Laccomimus improvidus Toledo & Michat” [red, rectangular, printed label].

Paratypes (26 exs, all bearing red, printed label “ PARATYPE Laccomimus improvidus Toledo & Michat”): Venezuela: same data of holotype (1 male VAIP); “Monagas State, 9°36.591'N, 63°8.295'W, 45 m, S. of Marturin, vegetated river”, “morichal margin, 2.II.2010, leg. Short & Garcia, VZ10-0202-01B” (1 male VAIP); “Monagas State, 8°46.439'N, 62°14.306'W, 19 m, between Tucupita and Temblador, pond margin, 3.II.2010, leg. Short, Garcia & Joly, VZ10-0203-02A” (1 male VAIP); each one of these two latter specimens bearing second label ( KUNHM-ENT) with its own barcode and catalogue number; “Km 88 El Dorado, Santa Elena BO, 160 m, 14.XI.1966, J. & B. Bechyne & E. Osuna” (1 male, 3 females MIZA); “Bolivar, Guri, Rio Caroni, 100 m, 16.XI.1966, J. & B. Bechyne & E. Osuna” (1 female MIZA); “Bolivar, Ana[illegible letter]oco, 60 m, 6°5',N 61°8'W, 10–30.VIII.1979 ” (1 male MIZA); “Aragua, El Limon, 450 m, 13. VII.1977, leg. B. Bechyne” (1 female MIZA); “Coje, Galeras del Pao, 28.VI.1963, leg. C. J. Rosales & A. Perez” (2 females MIZA); all these specimens in MIZA, bearing an additional printed green label “ MIZA ”. Suriname: “Paramaribo, Guest House of Museum, at light, 20.VIII–23.IX.1969, leg. N. Nieser” (1 male, 2 females NMW); idem except for “ 21–25.VIII.1969 ” (1 female NMW); idem except for “ 26. VII –7.VIII.1969 ” (1 female NMW); “ 55°06'W, 05°45'N, Oost-West Verbinding, 7–8 km E Meerzorg, 2.X.1969, leg N. Nieser (SN 157)” (1 male NMW); “ 55°11'W, 05°31'N, N banks of Coropinakreek, 25.IX.1969, leg N. Nieser (SN 156A)” (1 female NMW). Guyana: “Karanambo, 3°45.1'N, 59°18.6'W, blacklight on bank of Rupununi, 31.III.1994, P.J. Spangler, colln #2” (1 female USNM); idem except for “Buffalo Pond, 24.IV.1994, colln #11” (1 male USNM); “Pirara Ranch, 3°32.1'N, 59°40.5'W, Pirara River, 24.IV.1995, P.J. Spangler & A. Perry, colln #18” (1 female USNM).

Diagnosis. Externally indistinguishable from other species of Laccomimus , in particular from dark specimens of L. alvarengi and L. malkini with marked elytral pattern. Examination of female genitalia is also not diagnostic, except from L. malkini ; male genitalia are distinctive, however, with median lobe more straight and robust than in L. pumilio , with base and distal portion forming a more obtuse angle and apex ending in a wider expansion ( Fig. 89 a, b); left paramere similar to that of L. alvarengi , although not or very poorly thickened apically ( Fig. 89 c).

Description. TL: 2.0– 2.25 mm; MW: 1.0– 1.2 mm (holotype: TL: 2.2 mm; MW: 1.1 mm); A-TL: 2.2 mm; A- MW: 1.1 mm (NUM: 19 exs); drop-shaped, regularly tapering posteriorly; elytral subapical sinuation missing or hardly visible. Iridescence well visible.

Colour. Head and pronotum markedly paler than elytra. Head uniformly reddish-yellow, at most slightly darkened behind eyes; pronotum of same colour as head, with two brown, rectangular markings along both sides of hind margin. Elytra chestnut-brown, with vague yellow subbasal markings normally fragmented in spots; rarely missing. Apical fourth more or less gradually paler; a poorly defined paler area is often visible on lateral side. Underside uniformly testaceous to reddish-yellow. Antennae and mouthparts testaceous. Legs testaceous; metatarsi slightly darker.

Structures and sculpture. Head smooth, shiny, with fine microreticulation of rounded cells. Pronotum with microreticulation as on head, shiny, with faint iridescence. Smooth, lacking punctures except along hind and fore margins. Elytra apically not markedly pointed and subapical sinuation poorly or not pronounced; surface smooth, with punctures very scarce or lacking and often with few, very shallow, gnarled scratches; reticulation poorly impressed; iridescence well visible. Prosternal process and lobes of metacoxal processes as in L. alvarengi .

Male. Last abdominal ventrite tectiform, with antero-lateral sides markedly sinuate. Outer claw of forelegs scimitar-shaped. Median lobe of aedeagus very similar to that of L. pumilio except as follows: in left lateral view ( Fig. 89 a, b) more straight and robust, with base and distal portion forming a more obtuse angle; apex ending in a wider expansion, laterally flattened; in dorsal view ( Fig. 112 ) more gently attenuate at tip, almost straight, and dorsal lamina more strongly sinuate. Left paramere ( Fig. 89 c) very similar to that of L. alvarengi , although not or very poorly thickened apically.

Female. Elytra duller than in males, with more evident iridescence. Last abdominal ventrite triangular, very narrowly rounded to subtruncate at apex. Genital pieces as in L. pumilio .

Distribution. Venezuela, Guyana, Suriname ( Fig. 129 ).

Habitat. In Guarico State ( Venezuela) some specimens were collected in a large lagoon with vegetation, exposed to direct sunlight ( Fig. 133 ).

Etymology. Latin adjective for “surprising”, “unexpected”; quite late, in fact, we recognised it as a separate species.

Remarks. This species is close to L. pumilio and L. alvarengi . At first, after dissecting the first male specimen ( Suriname, Paramaribo), we were convinced that it was a dark specimen of L. alvarengi with an aberrant median lobe. We also considered that it could represent a possible case of hybridisation between L. alvarengi and L. bolivari since the median lobe appears as a broader tip added to an L. alvarengi median lobe. Both species occur at that locality. Additional material found in USNM and NMW, however, made it clear that the specimens belong to an undescribed species, very uniform in elytral colouration and in aedeagal features. Apparently it is a rare species, at present known only from few specimens, often found together with other species. The females are impossible to identify with certainty.

Figures

FIGURES 88 – 90. Male genitalia in Laccomimus species, left lateral view: 88) L. amazonas, a) median lobe, b) left paramere, c) right paramere; 89) L. improvidus, a) median lobe, b) magnification of apex of median lobe, c) left paramere; 90) L. youngi, a) median lobe (holotype), b) magnification of apex of median lobe (holotype), c) magnification of apex of median lobe (different specimen from type locality), d) left paramere (holotype), e) left paramere (different specimen from type locality).

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 126 – 129. Distribution maps of Laccomimus species: 126) L. bordoni in South America; 127) L. bolivari (full circles), L. youngi (single open square in Brazil); 128) L. pumilio (open circles), L. alvarengi in Central America (single triangle in Panamá), L. spangleri (stars), L. bordoni in Central America (asterisks); 129) L. improvidus.

FIGURES 132 – 133. Habitats of Laccomimus species: 132) L. distinctus, ditch at El Cachapé refuge, Chaco Province, Argentina (photo M. C. Michat); 133) L. improvidus and L. bolivari, large lagoon with vegetation ca. 65 km S Las Mercedes, Guarico State, Venezuela (photo A. E. Z. Short).