Laccomimus pumilio (LeConte, 1878) LeConte, 1878

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 : 316-317

Laccomimus pumilio (LeConte, 1878) comb. n.

( Figs 63 ; 67–68; 82–83; 91–93; 128)

Laccophilus pumilio LeConte, 1878: 596 ; Zimmermann 1920: 25.

Laccodytes pumilio (LeConte, 1878) . Young 1954: 48; Larson et al. 2000: 59; Nilsson 2001: 239.

Type locality. USA, Florida, Enterprise.

Type material. Holotype ( MCZ) not studied.

Material examined. Belize: British Honduras ( Belize), Corozal Town, 4–14.V.1967, George & Ruth Lacy (3 exs USNM); Toledo Dist., Blue Creek Village, 17.VI.1981, W.E. Steiner, taken at blacklight in rainforest valley near creek, Earthwatch Belize expedition 1981, D.H. Messersmith, W.E. Steiner et al. (1 ex. USNM); Cayo District, San Ignacio (14 km S), colln 17, 23.V.1987, Paul J. Spangler & Robin A. Faitoute / Collected at blacklight at Chaa River Cottages (16 exs USNM). Cuba: Cayamas, E.A. Schwarz collector (different dates hw: 7.V; 8.V; 9.V; 11.V. Year not signed. Two specimens with “Coll’n JD Sherman Jr. 1928”), most specimens bearing also an additional label “Laccophilis pumilo LeC. Det. F.N. Young” [handwritten by Young] (16 exs USNM); Laguna, Base J.A. Mella, 24.III.1973, V. Decu (1 ex. USNM). Guatemala: Izabal, Rio Dulce Fy., 2. VII.1974, W.E. Steiner (1 ex. USNM). USA: Florida, Dade Co., Homestead, 5.I.1977, W.E. Steiner (6 exs USNM); Florida, Alachua County, San Felasco, Hammock, T-9-6 R-19-E, Sec. 19, 478, 28.X.1947, F.N. Young (3 exs USNM; one bearing also “P.J. Spangler coll. 1958, 221697”); Florida, Alachua County, 28.X.1947, 478, F. Young / FIG [small, green printed label] (1 ex. USNM); Florida, Alachua County, San Felasco, Hammock, 1931, 24.VIII.1961, F.N. Young (1 ex. USNM); Florida, Sanford, 28.X.1960, BLT Gindess…[illegible] (1 ex. USNM); Florida, Gainesville, Doyle Cónner Building, 1–7.IX.1972, H.R. Dodge, light trap (1 ex. USNM); Florida, Collier Co., Marco, 1.I.1977, W.E. Steiner (1 ex. USNM); Florida, Collier Co., S of Indian Riserve, at light, 30.V.1993, T.A. Lott & D. Mattews leg. (3 exs MTP).

Diagnosis. Recognisable from most species of Laccomimus by aedeagal characters only, and from L. alvarengi (see below) by aedeagal characters and, usually, by a more uniform elytral colouration. Median lobe differentiated into basal and distal portion, divided by an angle or a curve ( Figs 91–93 ), with apex ending in small button-like expansion. The acuminate tip of the prosternal process is the most striking character, although hard to appreciate at low magnifications.

Description. Habitus ( Fig. 63 ). TL: 2.1–2.35 mm; MW: 1.05–1.2 mm; A-TL: 2.2 mm; A-MW: 1.1 mm (NUM: 34 exs); regularly drop-shaped, gradually narrowed backward; subapical sinuation not strongly pronounced; elytral tip rounded to almost truncate. Glossy; iridescence clearly visible on elytra and pronotum.

Colour. Head uniformly testaceous or slightly darkened on front, between eyes; pronotum testaceous, normally with wide, transverse brown band on basal half, where two darker, elongate spots are often visible close to posterior margin. Elytra chestnut brown, often with paler, hardly defined areas in subbasal, subapical and, normally, lateral position; otherwise uniformly brown or almost so. Underside testaceous, at most slightly darkened on sutures. Antennae and mouthparts testaceous. Legs testaceous; metatarsi slightly darker.

Structures and sculpture. Head smooth, shiny, with poorly impressed microreticulation of rounded cells and small scattered punctures. Pronotum shiny, with clear iridescence. Regular row of small punctures visible along both anterior and posterior margin, this latter interrupted at disc. Elytra gradually narrowed at tip, with subapical sinuation poorly marked; shiny, with clear iridescence; microreticulation quite impressed, accompanied by shallow and scattered punctures; a more or less regular, longitudinal row of small, shallow punctures is often (hardly) visible. Prosternal process ( Fig. 67 ) slightly carinate, acuminate at tip. Lobes of metacoxal processes regularly rounded in both sexes.

Male. Last abdominal ventrite tectiform, with antero-lateral sides visibly but not strongly sinuate. Outer claw of forelegs scimitar-shaped, sinuate, with ventral margin often slightly dentate ( Figs 82–83 ). Median lobe of aedeagus, in left lateral view ( Figs 91 a; 92a; 93a), with base and distal portion forming distinct angle; distal portion elongate and broader at middle length, then gradually narrowed to tip, visibly sinuate along both dorsal and, especially, ventral side, ending in small button-like expansion. In dorsal view same as in L. alvarengi (see Fig. 111 ); broadly lanceolate, gradually tapering apically and slightly turning right; dorsal lamina sinuate along its whole length; ejaculator groove strongly narrowed apically. Left paramere ( Figs 91 c; 92c; 93c) curved, apically thin and very poorly sinuate.

Female. Occasionally elytra and pronotum duller than in males. Last abdominal ventrite triangular, narrowly rounded at apex. Lateral tergites thin and partly membranous. Gonocoxal blade with single medial denticle. Ramus with large and spaced teeth; first tooth contiguous to apical hook, less developed with respect to second tooth, sometimes very reduced.

Distribution. So far known with certainty from USA (Florida), Belize, Guatemala, and Cuba ( Fig. 128 ). Young (1954) reported to have seen specimens from Jamaica and Haiti with male genitalia very similar to specimens from Florida and Cuba. All the specimens we have seen in USNM from Jamaica and Haiti are L. bordoni (see below). Mexico remains a large gap in the known distribution of this species (at present, Laccomimus is known to be represented in this country only by L. spangleri , see below) in spite of numerous field expeditions. Nevertheless, the occurrence of this beetle in Mexico is likely.

Notes on variability. At present this species is known to us from three populations: Florida, Belize, and Cuba, plus a single male from Guatemala. No substantial differences have been observed in the specimens from Belize and Guatemala in comparison with those from Florida. The specimens from Cuba exhibit some differences, mainly in the shape of the median lobe of aedeagus, where the separation between the base and the distal portion is arched instead of angulated ( Fig. 93 a), in the prosternal process which is less elevated and with less acuminate tip ( Fig. 68 ), and in having more developed pale patterns on elytra. These populations are somewhat similar to L. alvarengi (see below), and based on available information, we are not sure about the systematic position of the specimens. We hesitate to describe it as a new species at this time. Future collecting activities and/or molecular studies may clarify its status.

Remarks. The combination of a short and broad prosternal process, which is in lateral view straight and on the same level as the metaventrite, the outer protarsal claw of the male scimitar-shaped, the rounded or at most obtusely angulated metacoxal lobes, and the female gonocoxal blades with one tooth, distinguishes L. pumilio and related species (see below) within the genus. Among these, L. pumilio and L. alvarengi can be separated by aedeagal characters only.

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 91 – 93. Male genitalia in Laccomimus pumilio from different localities, left lateral view: 91) Belize, a) median lobe (showing also the three general parts of median lobe), b) magnification of apex of median lobe, c) left paramere, d) right paramere; 92) Florida, USA, a) median lobe, b) magnification of apex of median lobe, c) left paramere, d) right paramere; 93) Cayamas, Cuba, a) median lobe, b) magnification of apex of median lobe, c) left paramere, d) right 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 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.