Laccophilus leguyaderi, Manuel & Ramahandrison, 2020

Manuel, Michaël & Ramahandrison, Andriamirado T., 2020, Four new species of the diving beetle genus Laccophilus Leach, 1815 from Madagascar (Coleoptera, Dytiscidae, Laccophilini), Zootaxa 4822 (4), pp. 482-502 : 484-485

Laccophilus leguyaderi sp. nov.

Figures 1 , 5 , 9, 16 , 23, 24 .

Type locality. Madagascar, former province of Fianarantsoa, Andringitra National Park , ca. 4.2 km South of Antanifotsy, GPS coordinates S22°09’ E46°53’, altitude 1,970 m .

Type material. Holotype (♂): ” Madagascar. Ex-prov. / Fianarantsoa. ca 4.2 km S / Antanifotsy. 24 V 2016 / Ramahandrison & Manuel leg. // S22°09’ E46°53’ / Alt. 1,970m. Slowly flowing / rather deep brooklet, peaty / bottom. Andringitra NP” [pr], ” Holotype, Laccophilus leguyaderi sp. nov., Manuel & Ramahandrison 2020” [red, pr] ( MNHN) . Paratypes (in total 48♂♂, 47♀♀) ( BMNH, CMM, DEUA, MNHN, NHRS, NMPC, PBZT / MBC) : 16♂♂, 13♀♀, same data as holotype . 5♂♂, 3♀♀, ” Madagascar. Ex-Prov. / Fianarantsoa. ca 2.5 km / SSW Antanifotsy. 21 V 2016 / Manuel leg. // S22°08’ E46°53’ / Alt. 1,620m. Small stream / (just downstream spring) / in forest. Andringitra NP” . 3♀♀, ” Madagascar. Ex-prov. / Fianarantsoa. ca 4.2 km S / Antanifotsy. 22 V 2016 / Ramahandrison & Manuel leg. / S22°09’ E46°53’ // Alt. 1,970m. Narrow lake / fed by brook, sandy bottom, / in subalpine grassland. / Andringitra NP” . 1♀, ” Madagascar. Ex-prov. / Fianarantsoa. ca 4.3 km SW / Antanifotsy. 23 V 2016 / Ramahandrison & Manuel leg. // S22°09’ E46°53’ / Alt. 2,000m. Shallow brooklet, / peaty bottom, in subalpine / grassland. Andringitra NP” . 1♂, 1♀, ” Madagascar. Ex-prov. / Fianarantsoa. ca 4.3 km S / Antanifotsy. 24 V 2016 / Ramahandrison & Manuel leg. / S22°09 E46°54’ // Alt. 2,000m. Slowly flowing / stream with vertical bank / and peaty bottom. Subalpine / grassland. Andringitra NP” . 4♂♂, 1♀♀, ” Madagascar. Ex-prov. / Fianarantsoa. ca 4.2 km S / Antanifotsy. 24 V 2016 / Ramahandrison & Manuel leg. // S22°09’ / E46°54’ / Alt. 2,000m. Margin of / narrow lake, subalpine / grassland. Andringitra NP” . 15 ♂♂, 13 ♀♀, ” Madagascar: Fianarantsoa: Haute / Matsiara: Andringitra PN: Amporomahery / (circuit Imaitso ), S22.141116 E46.94196, / 1542m, 03.XII.2013, GB nets and sieves: / River Amporomahery near tourist trail, little / loop (petit boucle), Leg. J.H.Randriamihaja / & T.Ranarilalatiana: Field# MAD13-36 // NHRS-JLKB / 000070609” . 2 ♂♂, 4 ♀♀, ” Madagascar: Fianarantsoa: Haute / Matsiara: Andringitra PN: Belambo : / Cascade Riambavy : S22.1394 E46.8876, / 1657m, 01.XII.2013, GB nets and sieves: / river from the cascade with pools on the / rocks, Leg. J.H.Randriamihaja & / T.Ranarilalatiana: Field# MAD13-30 // NHRS-JLKB / 000070619” . 5 ♂♂, 8 ♀♀, ” Madagascar: Fianarantsoa: Haute Matsiara: / Andringitra PN: Camp 2, river running into / cascade Riambavy : S22.151016 E46.89163, / 1965m, 02.XII.2013, GB nets and sieves: / river with pools surrounded by regular / burning area, Leg. J.H.Randriamihaja & / T.Ranarilalatiana: Field# MAD13-35 // NHRS-JLKB / 000070623”. All paratypes with the respective printed red label .

Description of holotype. Habitus ( Fig. 1 ) oval, with lateral sides widely rounded, posteriorly strongly tapered to rather narrowly rounded apex; lateral outline continuous between pronotum and elytra; maximum body width at about 41% of total body length and about 27% of elytral length; dorsal surface evenly and moderately convex; in lateral view maximum height slightly posterior to first third of total length.

Colouration. Dorsal surface of head rufo-testaceous. Pronotum rufo-testaceous, narrowly darkened along posterior margin. Elytron with typical alluaudi- group colour pattern as in Fig. 1 ; brown longitudinal vittae well-defined and rather strongly contrasting with testaceous background, leaving wide basal area and humeral region entirely testaceous; pale stripes between dark longitudinal vittae irregularly interrupted. Pronotal epipleura, propleura, lateral parts of prosternum, and diffusely delimited narrow area along lateral margin of metacoxal plate brown; rest of ventral surface rufo-testaceous ( Fig. 5 ). Antennae, palps, anterior and median legs testaceous; posterior legs rufotestaceous.

Head. Anterior outline of clypeus widely rounded, subtruncated in middle. Surface shiny, with double reticulation; large meshes irregular and of variable sizes, more strongly impressed than small meshes; with sparse micropunctures, on vertex denser and coarser; larger punctures present along inner eye margins and in two irregular transverse rows sub-laterally on frons.

Pronotum. Lateral margins evenly arcuate. Surface shiny, with double reticulation; large meshes irregular and of variable sizes, more strongly impressed than small meshes; small meshes rounded, more strongly impressed than on head; punctation inconspicuous except in anterior quarter and close to posterior angles with sparse, moderately large and coarse punctures.

Elytron. Surface shiny, with double reticulation; large meshes indistinct except in scutellar region; small meshes irregularly polygonal, of rather homogeneous sizes, larger and much more strongly impressed than on pronotum; punctation inconspicuous beyond rather indistinct discal and lateral puncture rows.

Ventral surface. Prosternal process lanceolate, strongly convex, with apex acutely pointed. Metacoxal lines anteriorly subparallel. Apical abdominal ventrite strongly convex, in posterior half almost tectiform; without protuberance; posterior margin unmodified, straight on each side of slightly produced, rounded apex. Entire ventral surface very shiny; on elytral epipleura, metaventrite, metacoxa and abdominal ventrites with very fine regular microstriae; on abdominal ventrites with oblique striae, more strongly impressed on ventrites I–III; surface impunctate except on antero-medial prosternal region, anterior region of metaventrite and apical abdominal ventrite with shallow punctures of moderate size. Metacoxal plate without stridulatory apparatus.

Legs. Mesotibia strongly modified, very broad with dorsal outline strongly curved, ventral outline straight ( Fig. 5 ); along dorsal edge with row of very long setae; anterior surface mat, with very dense small punctures bearing short setae except in basal quarter and narrowly along apical margin (surface shiny, almost impunctate). Pro- and mesotarsomeres I–III rather strongly broadened, with four ventral transverse dense rows of adhesive setae. Protarsal claws about as long as protarsomere V; length of mesotarsal claws about 3/4 length of mesotarsomere V.

Aedeagus. Median lobe in lateral view as in Fig. 9 , in ventral view as in Fig. 16 ; parameres as in Figs. 23–24 .

Females. Mesotibia distinctly narrower (yet broader than usual in Laccophilus ); with row of long setae along dorsal edge less developed; anterior surface more shiny, with small punctures distinctly larger and sparser and impunctate area along apical margin wider. Pro- and mesotarsi not broadened, without ventral adhesive setae.

Variability. Specimens vary slightly in habitus (length / width ratio) and dorsal colour pattern mainly with respect to intensity of the elytral brown longitudinal markings and degree of fragmentation of the pale interspaces between these dark bands, the overall elytral pattern being nevertheless highly stable.

Measurements. Holotype: TL = 4.1 mm, TL without head = 3.9 mm, MW = 2.3 mm, ratio TL/MW = 1.80. Paratypes: TL = 3.95–4.5 mm (4.28±0.12), TL without head = 3.7–4.3 mm (4.06±0.11), MW = 2.2–2.5 mm (2.37±0.08), TL/MW = 1.73–1.91 (1.81±0.04).

Differential diagnosis. This species and the following one differ from all other known alluaudi -group species by the combination of elytral colour pattern (notably with particularly broad pale area between anterior elytral margin and anterior extremity of the dark longitudinal markings), brown colouration of the ventral surface of the prothorax, and shape of the median lobe of aedeagus. For differences with L. bergsteni sp. nov., see below under diagnosis of L. bergsteni .

Habitat. This species was collected at an altitude range of 1,540 –1,990 m. It lives at shallow depth along the margins of slowly-flowing brooks, streams or rivers and associated pools, as well as small to large lentic water bodies with inflow and outflow ( Figs. 43–44 ). Some collecting sites were located in forest, but the species is also present above tree line in subalpine grassland (e.g., sampling site shown in Fig. 43 ). It prefers habitats with substratum moderately to heavily loaded with organic matter (most often including a fine brown organic mud component, together with macroscopic vegetal remnants of trees and/or helophytes) and clear water, with or without vegetation.

Distribution. So far known only from the Andringitra massif in central-southern Madagascar ( Fig. 53 ).

Derivatio nominis. This species is dedicated to Prof. Hervé Le Guyader (Institut de Systématique, Evolution, Biodiversité, Sorbonne Université, Paris). The species name is a noun in the genitive singular.

Figures

FIGURE 53. Map showing the distribution of known localities of the newly described species. Red dot: L. leguyaderi; Blue dots: L. bergsteni; Magenta dot: L. bergsteni and L. rakouthae; yellow dot: L. makay. Names of corresponding protected areas or massifs indicated in italics above dots.

FIGURES 1–4. Habitus in dorsal view of: (1) Laccophilus leguyaderi sp. nov. (holotype); (2) Laccophilus bergsteni sp. nov. (holotype); (3) Laccophilus makay sp. nov. (holotype); (4) Laccophilus alluaudi (male specimen from Isalo massif). Scale bar: 1 mm.

FIGURES 5–8. Ventral surface of: (5) Laccophilus leguyaderi sp. nov. (holotype); (6) Laccophilus bergsteni sp. nov. (holotype); (7) Laccophilus makay sp. nov. (holotype); (8) Laccophilus alluaudi (male specimen from Isalo massif). Scale bar: 1 mm.

FIGURES 9–22. Median lobe of aedeagus in lateral (9–15) and ventral (16–22) view of: (9, 16) Laccophilus leguyaderi sp. nov. (holotype); (10, 17) Laccophilus bergsteni sp. nov. (holotype); (11, 18) Laccophilus makay sp. nov. (holotype); Laccophilus alluaudi, male specimens from (12, 19) Montagne d’Ambre, (13, 14, 20, 21) Isalo massif, and (15, 22) Ibity massif. Scale bar: 0.1 mm.

FIGURES 23–30. Left (23, 25, 27, 29) and right (24, 26, 28, 30) parameres of: (23, 24) Laccophilus leguyaderi sp. nov. (holotype); (25, 26) Laccophilus bergsteni sp. nov. (holotype); (27, 28) Laccophilus makay sp. nov. (holotype); (29, 30) Laccophilus alluaudi (male specimen from Isalo massif). Scale bar: 0.1 mm.

FIGURES 43–46. Habitats of Laccophilus leguyaderi sp. nov. (43–44) and Laccophilus bergsteni sp. nov. (45–46). (43) Shallow brooklet with peaty bottom in subalpine grassland (Andringitra massif, 2,000 m); (44) Rather deep brook with peaty bottom, slowly flowing among subalpine shrubs (Andringitra massif, 1,970 m; type locality of L. leguyaderi); (45) Slowly flowing stream in natural forest with muddy bottom and lots of tree leaves (Ankaratra massif, Tavolotara, 2,000 m); (46) Slowly flowing stream on flat area in subalpine grassland (Ankaratra massif, 2,400 m; type locality of L. bergsteni).