Laccomimus alvarengi, 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 : 317-319

Laccomimus alvarengi sp. n.

( Figs 3 ; 5; 11; 14–15; 28; 39; 57; 64; 69; 77–81; 94–102; 111; 118; 125; 128)

Type locality. Brazil, Mato Grosso, Jacaré, Xingu National Park.

Type material. Holotype male ( USNM): dissected for genitalia probably by Young; genitalia and last two abdominal ventrites glued on separate label under the holotype “ Brazil, Matto [sic] Grosso, Jacaré, P.N. Xingu, XI.1961, Alvarenga & Werner leg” [printed], “FIC” [small, pink, printed label]”, “ Laccomimus alvarengi Young ” [white label, handwritten by Young], “ HOLOTYPE Laccomimus alvarengi Toledo & Michat” [red, rectangular, printed label].

Paratypes (200 exs all bearing red, printed label “ PARATYPE Laccomimus alvarengi Toledo & Michat”): Brazil: same data as holotype (10 exs USNM); same data as holotype except for “ XI.1965 ” (65 exs USNM –most of them without label); “Mato Grosso, Cuiabá, 30.III.1972, W.H. Withcomb” (8 exs USNM); idem but “ 9.IV.1972 ” (6 exs USNM); idem but “ 11.IV.1972 ” (3 exs USNM); idem but “ 21.IV.1972 ” (1 ex. USNM); idem but “ 22.IV.1972 ” (7 exs USNM –four of which without label); “Mato Grosso, Rio Bento Gomes (Pantanal), 1993– 1994, E. Stuhr leg.”, “Flussabschnitt bei [= section of river at] Periquito, 15°54' S, 56°33' W ” (1 ex. NMW); “Rondôna, 62 km SW Ariquemes, nr. fz. Rancho Grande, 8–20.IX.1994, JE Eger & C.W. O’Brien leg” (3 exs ZSM); “Minas Gerais, Prov. Cordisburgo, Faz. Pontinha, XII.1997, leg. F.Z. Vaz-de-Mello, coll. L. Hendrich” (16 exs ZSM); “Par. Curitiba, 28.VI.1969, leg. P.& P. Spangler” (1 ex. USNM). Argentina: “Prov. Corrientes, Mbrucuyá N.P., 15–17.I.2004, light trap, leg. M.C. Michat” (24 exs MCMC). Bolivia: “Beni, 40 km E San Borja, Estacion Biologica Beni, Estancia El Porvenir, 6–8.IX.1987, M. E. Steiner”, “At black light, open grass savanna and marsh” (7 exs USNM); “Guayaramerin, Beni, river bank, Soil Zoological Exp., Balogh, Mahunka, Zicsi”, “No. 428, beaten from vegetation, 2.XII.1966 ” (2 exs HNMB); “El Beni, Beni Station, NE of San Borja, 31. VII.1988 ”, “Robert W. Brooks ex., at lights, BIOLAT-SI/MAB” (2 exs VAIP); “El Beni, El Porvenir Station, NE of San Borja, 6–9.VIII.1988 ”, “Robert W. Brooks ex., at lights, BIOLAT-SI/MAB” (1 ex. VAIP); “Santa Crus, Sara, 2 km NW Santa Rosa, 21.II.1969, BLT A. Martinez & R.E. Woodruff” (5 exs USNM); idem “ 3 km S Santa Rosa, 22.II.1969 ” (7 exs USNM). Ecuador: “Esmeraldas, 9 km S San Lorenzo, 25.V.1979, ultraviolet light, Jos. J. Anderson”, “ Ecuador Peace Corps, Smithsonian Institution Aquatic Insects Survey” (3 exs USNM –one ex. without label); “Los Rios, Babahoyo, 21.VI.1975, Cohen, Langley & Monnig”, “ Ecuador Peace Corps, Smithsonian Institution Aquatic Insects Survey” (2 exs USNM). Panamá: “C. Z. [= Canal Zone], Albrook Forest site, 21–22.IX.1967, BLT RS Hutton” (1 ex. USNM). Perú: “Prov. Loreto, Rio Yarapa, Puerto Miguel”, “ 200 m, 16–23.XII.1994, T. Hàcz & G. Holzinger” (3 exs HNMB); “Loreto, Yacumama Lodge, 73.6°W, 4.8°S, nr. junction Rio Maranon - Rio Ucayali, 6–20.VIII.1994, Skelly leg., small light in wood, coll. L. Hendrich” (8 exs ZSM); “Colonia Calleria, Rio Calleria, 15 km E Ecayali, muddy river shore, 12–25.X.1961, B. Malkin” (2 exs USNM); “Madre de Dios, Rio Tambopata Res., 30 air km SW Pto. Maldonado, 290 m, 2–5.XI.1979, J. B. Heppner, subtropical moist forest” (3 exs USNM). Paraguay: “Jejuí-Mí, light trap, 18.XII.2003, leg. M.C. Michat” (2 exs MCMC); “Dep. Alto Paraguay, Campo Grande Farm, light trap, 7.XII.2002, leg. M.C. Michat” (2 exs MCMC); “Dep. Alto Paraguay, rd. to Fortín Patria, 3.XII.2002, light trap, leg. M.C. Michat” (4 exs MCMC); “Dep. Alto Paraguay, Defensores del Chaco N.P., Fortín Madrejón, 23.XI.2002, light trap, leg. M.C. Michat” (2 exs MCMC); “Dep. Cordillera, Arroyos y Esteros, 8.IX.1991, Ulf Drechsel leg., Coll. Hendrich” (1 ex. ZSM); “Dep. Central, Asuncion, Rio Paraguay, 2.XI.1990, Ulf Drechsel leg., Coll. Hendrich” (1 ex. ZSM). Suriname: “Paramaribo, Guest House of Museum, at light, 19–20. VII.1969, leg N. Nieser” (1 ex. NMW); idem except for “ 21–25.VIII.1969 ” (1 ex. NMW).

Diagnosis. Recognisable from most species of Laccomimus by aedeagal characters only, and from the very close L. pumilio (see above) by aedeagal characters and, frequently, by the more distinct pattern on elytra. Median lobe differentiated into basal and distal portion, divided by an angle or a curve ( Figs 94–102 ), with apex ending in small button-like expansion. The rounded tip of the prosternal process, which is very different from the acuminate tip of L. pumilio , is constant in this species. The average size is smaller with respect to L. pumilio .

Description. Habitus ( Fig. 64 ). TL: 1.9–2.25 mm; MW: 0.95–1.2 mm (holotype: TL: 2.2 mm; MW: 1.1 mm); A-TL: 2.1 mm; A-MW: 1.1 mm (NUM: 47 exs); very similar to L. pumilio except for aedeagal characters, shape of prosternal process and, frequently, elytral colouration.

Colour. Variable. Pale patterns of elytra normally (but not always) more sharply defined on darker background and often more extended with respect to L. pumilio . Most commonly pale subbasal band of elytra fragmented in semicircular spots, although strong variability occurs (see below). Pronotum normally with narrower dark transversal band, more evidently bicolour; head, antennae, mouthparts, legs, and underside as in L. pumilio .

Structures and sculpture. Mostly as in L. pumilio , but prosternal process rounded at tip and elevated, not carinate ( Figs 28 ; 69); iridescence on pronotum and mainly on elytra often more intense.

Male. Last abdominal ventrite as in L. pumilio . Outer claw of forelegs scimitar-shaped, variable in shape, often with denticles on ventral margin ( Figs 77–81 ). Median lobe of aedeagus in dorsal view as in Fig. 111 ; same as in L. pumilio (see description above). In left lateral view variable ( Figs 94 a; 95a, 96a; 97a; 98a; 99a; 100a; 101a; 102a): in holotype ( Fig. 94 a) base and distal portion forming a curve instead of an angle, distal portion less elongate with respect to L. pumilio and more uniformly wide along its length, although visibly sinuate on apical half. Left paramere ( Figs 94 c; 95c; 96c; 97c; 98c; 101c; 102c) strongly sinuate apically, expanded and thickened.

Female. Often duller than males, with more intense iridescence. Genital pieces ( Fig. 118 ) as in L. pumilio .

Distribution. Laccomimus alvarengi is one of the most widespread and variable member of Laccomimus : Argentina, Bolivia, Brazil, Ecuador, Panamá, Paraguay, Perú, Suriname ( Figs 125 ; 128). It has not been recorded from Venezuela, however, in spite of VAIP’s intensive collections during the last decade.

Etymology. Frank N. Young and Paul J. Spangler named, in litteris, this taxon “ Laccomimus alvarengi n. sp. ”, in honour of the collector Moacir Alvarenga (cf. Young 1974: 2, 3). The specific epithet is a noun in the genitive case.

Notes on variability. L. alvarengi is more variable than L. pumilio . Except for the striking differences in the prosternal process, morphological separation of the two species is often difficult. The visibly sinuate and expanded apex of the left paramere and the less broadened distal portion of the median lobe seem to be constant diagnostic characters of L. alvarengi with respect to L. pumilio . In other features the median lobe is very variable, and this variability has been observed in different populations. Intermediate forms between the holotype of L. alvarengi and Florida specimens of L. pumilio have been observed frequently, even in exemplars from the same locality (see for example Fig. 97 ). In most cases, however, the aedeagus is distinctive with respect to L. pumilio , particularly in the angulated separation between the base and distal portion and the somewhat widened distal portion. An aberrant median lobe was found dissected from a specimen collected at the type locality ( Fig. 95 ). Colouration is also very variable. Normally the elytral patterns in L. alvarengi are more defined than in L. pumilio , and some populations exhibit very bright elytral patterns, including large and complete pale subbasal bands ( Fig. 64 a, b).We have observed, however, specimens (especially from Brazil) with obscure or reduced pale markings, similar to L. pumilio . Uniformly dark-chestnut elytra occur in few specimens from Brazil and Paraguay. Since the shape of the prosternal process unambiguously separates L. alvarengi from L. pumilio , and a visibly sinuate and expanded apex of the left paramere and a less broadened distal portion of the median lobe are also apparently constant differences, we decided to describe L. alvarengi as a distinct species and not as a subspecies within L. pumilio .

Remarks. See under L. pumilio .

Figures

FIGURES 1 – 7. 1) Habitus of Laccomimus bolivari, dorsal view (Photo A. E. Z. Short); 2) habitus of Laccodytes apalodes, dorsal view (Photo A. E. Z. Short); 3 – 7) SEMs of Laccomimus species (females): 3) habitus of L. alvarengi, dorsal view; 4) habitus of L. bordoni, dorsal view; 5) pronotum of L. alvarengi, dorsal view; 6) pronotum of L. bordoni, dorsal view; 7) pronotum of L. bordoni, dorsolateral view.

FIGURES 94 – 97. Male genitalia in Laccomimus alvarengi from different localities, left lateral view: 94) holotype, a) median lobe, b) magnification of apex of median lobe, c) left paramere; 95) likely aberrant specimen from type locality, a) median lobe, b) magnification of apex of median lobe, c) left paramere; 96) Loreto, Perú, a) median lobe, b) magnification of apex of median lobe, c) left paramere, d) right paramere; 97) Mbrucuyá National Park, Argentina, a) median lobe, b) left paramere.

FIGURES 98 – 102. Male genitalia in Laccomimus alvarengi from different localities, left lateral view: 98) Mbrucuyá National Park, Argentina, a) median lobe, b) left paramere; 99) Beni, Bolivia, a) median lobe, b) magnification of apex of median lobe; 100) Santa Rosa, Bolivia, median lobe; 101) Esmeraldas, Ecuador, a) median lobe, b) left paramere; 102) Albrook, Panamá, a) median lobe, b) magnification of apex of median lobe, c) left paramere.

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 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 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.