Laccomimus distinctus, 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 : 310-312

Laccomimus distinctus sp. n.

( Figs 8 ; 20–22; 32–36; 44–46; 59; 73; 84; 107; 116; 122; 131–132; 138)

Type locality. Panamá, Canal Zone, Albrook Forest.

Type material. Holotype male ( USNM): dissected for genitalia probably by Young; aedeagus and last two ventrites glued on pointed card pinned under the holotype “ Panama, C. Z. [Canal Zone], Albrook Forest site, ground, XI.16 -17.1967, BLT R.S. Hutton” [printed label with date and “ground” handwritten], “ HOLOTYPE Laccomimus distinctus Toledo & Michat” [red, rectangular, printed label].

Paratypes (244 exs all bearing red printed label “ PARATYPE Laccomimus distinctus Toledo & Michat”): Panamá: same data as holotype, except for: “ 9–16.X.1967 ” (1 ex. USNM); “ 16–17.XI.1967 ” (1 ex. USNM); “ 14– 16.XII.1967 ” (1 ex. USNM); “ 21–22.XII.1967 ” (1 ex. USNM); “ 28–29.XII.1967 ” (2 exs USNM); “Canal Zone, 5 mi SSW Gatun Dam, 30.XII.1987, MacDonald & Schiefer”, “William H. Cross Expedition” (1 ex. MEM); “Darien, 5 km W Meteti, 9.I.1988, MacDonald & Schiefer”, “William H. Cross Expedition” (13 exs MEM); “Tocumen, 6–10. VII.1970, D. Navas BLT ” [hw](1 ex. USNM); idem “ 26–30. VII.1970 ” [hw] (5 exs USNM –all but one unlabelled); idem “ 31.VIII–4.IX.1970 ” [hw] (1 ex. USNM); idem “ 7–11.IX.1970 ” [hw](2 exs USNM –one unlabelled); idem “ 9–16.IX.1970 ” [printed] (14 exs USNM). Argentina: Prov. Corrientes, Mbrucuyá N.P., 15– 17.I.2008, light trap., leg. M.C. Michat” (14 exs MCMC); “Prov. Santiago del Estero, Salada Lagoon, Los Juríes, 3.IV.2002, leg. M.C. Michat” (2 exs MCMC); “Prov. Santiago del Estero, Copo N.P., 27.III.2001, light trap, leg. M.C. Michat” (1 ex. MCMC); “Prov. Formosa, El Bagual Reserve, 7.X.2002, leg. M.C. Michat” (1 ex. MCMC); “Prov. Chaco, El Cachapé, 4.XII.2008, ditch, leg. M.C. Michat” (7 exs MCMC); “Prov. Chaco, 97 km NW of Resistencia, 10 km W of Capitán Solari, 26°48'32"S 59°36'29"W, 3–7.II.2004. [collector not given]” (10 exs NHMP –two of them bearing additional “Coll. Jiří Hájek National Museum Prague, Czech Republic ”); “Chaco, San Bernardo, III.1994, leg. O. Di Iorio” (1 ex. NMW). Bolivia: “Guayaramerin, Beni, river bank, Soil Zoological Exp., Balogh, Mahunka, Zicsi”, “No. 428, beaten from vegetation, 2.XII.1966 ” (4 exs FF HNMB); “Guayaramerin, Beni, outskirts of town, Soil Zoological Exp., Balogh, Mahunka, Zicsi”, “No. 424, lamping., 1.XII.1966 ” (1 ex. HNMB); “Santa Cruz, Buena Vista, 400 m, m. v. light , 20.X.1994, R. Ward. leg.” (1 ex. LHB); “Santa Cruz, Sara, 3 km S Santa Rosa, 22.II.1969, BLT A Martinez & RS Woodruff” (14 exs USNM); idem “ 2 km NW Santa Rosa, 21.II.1969 ” (2 exs USNM). Brazil: “Mato Grosso, Cuiabà [Cuyabà], BLT 30.III.1972, WH Whitcomb” (2 exs USNM); idem “ 4.IV.1972 ” (1 ex. USNM); idem “ 5.IV.1972 ” (1 ex. USNM); idem “ 7.IV.1972 ” (2 exs USNM); idem “ 9.IV.1972 ” (1 ex. USNM); idem “ 21.IV.1972 ” (1 ex. USNM); idem “ 22.IV.1972 ” (3 exs USNM); idem “ 24.IV.1972 ” (2 exs USNM); “Sao Paulo, Piracicaba, 10.II.1966, Black light, C.A. Triplehorn” (17 exs USNM); “Minas Gerais, Aguas Vermelhas, XII.1998, leg. A. Bello & F.Z. Vaz-de-Mello, coll. L. Hendrich” (11 exs ZSM); “Minas Gerais Prov., Cordisburgo Faz., Pontinha, XII.1997, leg. F.Z. Vaz-de-Mello, coll. L. Hendrich” (3 exs ZSM). Colombia: “Rio Frio, Magdalena, VI.1916, Darlington” (17. exs USNM); “Aracataca, Magdalena., Darlington” (2 exs USNM). Costa Rica: “Prov. Puntarenas (CR4), Qu. Negra, ca. 8 km NW Golfito, nr. La Gamba (vill.), at Field Station La Gamba, 90 m a.s.l., 8°42'06"N, 83°12'07"W, 1–3.III.2009, leg. M. Brojer” (1 ex. NMW); same data except for “ 1–7.III.2009 ” (1 ex. NMW). French Guyana: “FG/09, Piste N2 Auberge ‘Elevage de la Chaumiere’, 3.X.2009, lg. A. Dostal” (1 ex. NMW). Paraguay: “ Paraguay, Vezényi”, “Asuncion, 1904”, “ Laccodytes perparvulus Rég., F. Guignot det., 1955” (1 ex. HNMB); “Dept. S. Pedro, Nueva Germania, 12– 22.I.1991, leg. U. Drechsel” (2 exs NMW); “Dep. Central, Asunciòn, 30.IX.1991, U. Drechsel leg. ” (1 ex. ZSM); idem “ 2.X.1992 ” (1 ex. NMW); idem “Capiata, 3.X.1994 ” (1 ex. NMW); idem “Capiata, Sabana de Agrocomia Totai, 2.X.1994 ” (1 ex. NMW); “Dep. Cordillera, Arroyos y Esteros, 11.IX.1991, Drechsel leg.” (3 exs LHB); “Dep. Guairá, Garsy [or Garay?], 20.VIII.1992, Ulf Drechsel leg.” (17 exs LHB); “Dep. Paraguari, Sapucal, 4.X.1992, Dreschsel leg.” (1 ex. LHB); “Dep. Alto Paraguay, Defensores del Chaco N.P., Fortín Madrejón, 23.XI.2002, light trap, leg. M.C. Michat” (1 ex. MCMC); “Dep. Presidente Hayes, Transchaco rd., 5 km SE Pozo Colorado, 22.XI.2002, light trap, leg. M.C. Michat” (3 exs MCMC). Venezuela: “Guárico State, 9°46.320'N, 67°21.177'W, 280 m, rio San Antonio, N. Dos Caminos, side stream, 8.I.2009, leg. Miller & Short, VZ09-0108- 02B” (1 ex. VAIP); idem except “mic. habitats, leg. K.B. Miller, VZ09-0108-02C” (1 ex. VAIP); “Guárico State, 9°6.794'N, 66°59.595'W, 152 m, stream at road crossing N. of Palenque, stream, 8.I.2009, leg. Short, Garcia, Miller, Camacho & Joly, VZ09-0108- 03X ” (3 exs VAIP); “Guárico State, 8°316.7050'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 ” (6 exs VAIP); “Apure State, 7°37.298'N, 69°3.679'W, 83 m, side road ca. 10 km E Mantecal, marshy area and pool by road, 18.I.2009, leg. Short, Garcia & Camacho, VZ09-0118- 02X ” (19 exs VAIP; one ex. bearing additional label “ Laccodytes det. A.E.Z. Short 2009”); “Apure State, 7°38.660'N, 69°18.004'W, 90 m, between ‘La Ye’ [La Yeguera?] and Bruzual, lagoon, 18.I.2009, leg. Short, Garcia & Camacho, VZ09-0118- 03X ” (2 exs VAIP); “Apure State, 8°2.534'N, 69°20.530'W, 83 m, edge of Bruzual, large marsh, 18.I.2009, leg. Short, Garcia & Camacho, VZ09-0118- 04X ” (1 ex. VAIP); “Portuguesa State, 8°25.773'N, 69°35.202'W, 185 m, Rio Guanare N. of Guanare, 19.I.2009, leg. Garcia, VZ09-0119-02B” (1 ex. VAIP); “Zulia State, 9°51.883'N, 72°43.285'W, 96 m, between Machiques and Tukuko, road side marsh, 29.I.2009, leg. Short, Garcia, Camacho, VZ09-0129- 03X ” (1 ex. VAIP); “Barinas State, 8°28.477'N, 70°32.194'W, 205 m, E. Los Pasitos, marshy pond on hacienda, 14. VII.2009, leg. Short et al, VZ09-0714-05A” (1 ex. VAIP); “ Amazonas State, 2°10.591'N, 63°08.295'W, 45 m, S. of Maturin, vegetated river”, “morichal margin, 2.II.2010, leg. Short & Garcia, VZ10-0202-01B” (2 exs VAIP); “Sucre State, 10°31.419'N, 63°07.070'W, 2 m, ca. 5 km SE El Pilar, forested swamp by road, 28.I.2010, leg Short & Garcia, VZ10-0129-04A” (5 exs VAIP); “Delta Amacuro, 9°012'00"N, 61°53'21.3"W, 3m, transect#3, temporary rain pond, 28.VIII.2009, leg. L. Cordero,VZ09-0828-36A” (1 ex. VAIP); “Delta Amacuro, 9°10.504'N, 61°54.610'W, 8 m, between Tucupita & Los Güires, marsh by road, 3.II.2010, leg Short & Garcia, VZ10-0203-01A” (1 ex. VAIP); each specimen in VAIP bearing additional label ( KUNHM-ENT) with its own barcode and catalogue number.

Diagnosis. One of the most distinctive species of Laccomimus based on the following combination of characters: elytra typically with sutural band darker than rest of surface, which is normally pale brown, gradually faded subbasally and subapically. Male: lobes of metacoxal processes ending in spine, foreclaws unmodified and median lobe characteristically curved. Female: lobes of metacoxal processes in most cases angulated, with gonocoxal blades with two teeth.

Description. Habitus ( Fig. 59 ). TL: 2.05–2.4 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: 91 exs); drop-shaped, regularly narrowed posteriorly. Smooth; strongly iridescent on elytra and, often, pronotum.

Colour. Pronotum testaceous; head and elytra darker. Head gradually paler on front and clypeus; elytra normally faded on apical fourth and with confuse and often fragmented yellow band at base; sutural band normally visibly darker than rest of elytra. Underside mainly testaceous, often darkened on metaventrite and metacoxal plates. Antennae and mouthparts testaceous. Legs testaceous; metatarsi slightly darker.

Structures and sculpture. Head smooth, shiny, with microreticulation fine and hard to recognise. Pronotum smooth, with few shallow and fine punctures scattered on disc, more numerous along sides. File of punctures along hind margin poorly impressed. Elytra shiny, strongly iridescent, covered by fine but quite impressed microreticulation, together with shallow punctures arranged in irregular, longitudinal series and light roughness in some parts. Prosternal process elongate, clearly carinate, acuminate at tip, reaching mesocoxae ( Figs 20–22 ). Lobes of metacoxal processes ending in tooth or simply acute tip, depending on sex (see below).

Male. Lobes of metacoxal processes ending in acute tooth ( Fig. 32 ). Last abdominal ventrite tectiform, with antero-lateral sides from rectilinear to visibly sinuate. Outer claw of forelegs unmodified, similar to inner claw ( Figs 44–45 ; 73). Median lobe of aedeagus, in left lateral view ( Fig. 84 a) straight, then typically curved on apical third, which is flattened like a leaf, ending in small apical expansion. In dorsal view ( Fig. 107 ) somewhat wide, with almost parallel sides, abruptly narrowed on apical fourth; dorsal lamina narrow and straight; ejaculator groove very wide up to narrowed apical fourth. Left paramere ( Fig. 84 b) poorly but regularly curved, bent down apically.

Female. Lobes of metacoxal processes ending in acute angle; rarely with small apical tooth, but less developed than in males, otherwise almost rounded ( Figs 33–36 ). Last abdominal ventrite triangular, almost pointed at apex.

Lateral tergites wide and sclerotized; gonocoxal blade ( Fig. 116 a) with second subapical denticle at about ¾ of its length. Ramus ( Fig. 116 b) with moderately large but dense teeth; normally first tooth, following apical hook, less developed.

Distribution. Argentina, Bolivia, Brazil, Colombia, Costa Rica, French Guyana, Panamá, Paraguay, Venezuela ( Fig. 122 ).

Habitat. As for most species of this genus, the principal source of material studied was collected at lights. Nevertheless, recent field data suggest a wide ecological range for this species, in both stagnant and running waters (Figs 131–132; 138). In El Cachapé refuge ( Argentina) some specimens were collected in the vegetated margins of a small semipermanent pond about 15 m long, 5 m wide and 70 cm in depth, with clear water and exposed to insolation (Figs 131–132).

Etymology. The specific epithet refers to the distinctive features of both sexes of this species. It is an adjective in the nominative singular.

Notes on variability. Paler patterns on the elytra vary from more or less extended and more or less defined to obscure. In females, the lobes of the metacoxal processes often vary in shape within the same population. The aedeagus and female sexual structures seem to be quite homogeneous.

Remarks. This is a very distinct species, characterised by the long, almost Laccophilus -like prosternal process, unmodified male protarsal claws, and angulated or even toothed lobes of the metacoxal processes in females. These features are not found in any other species of Laccomimus , whereas two-toothed gonocoxal blades in females occur also in L. malkini (see below).

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 44 – 51. SEMs of left protarsus in Laccomimus species (males): 44) L. distinctus, general view; 45) idem, detail at higher magnification of last protarsal segment and claws; 46) idem, detail at higher magnification of stalked suction palettes; 47) L. amazonas, general view; 48) idem, detail at higher magnification of stalked suction palettes; 49) L. bordoni, general view; 50) idem, detail at higher magnification of last protarsal segment and claws; 51) idem, detail at higher magnification of stalked suction palettes.

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.