Laccophilus makay, 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 : 491-493

Laccophilus makay sp. nov.

Figures 3 , 7 , 11, 18 , 27, 28 .

Type locality. Madagascar, former province of Toliara, Makay massif, ca. 10.7 km North-West of Tsivoky, GPS coordinates S21°13’ E45°18’, altitude 540 m.

Type material. Holotype (♂): ” Madagascar. Ex-prov. / Toliara. ca 10.7 km NW / Tsivoky. 07 VI 2016. / Manuel leg. // S21°13’ E45°18’. Alt. 540m. / Shadowed pools beneath / rock wall in a canyon. / Makay massif” [pr], ” Holotype, Laccophilus makay sp. nov., Manuel & Ramahandrison 2020” [red, pr] ( MNHN) . Paratypes (in total 48♂♂, 34♀♀) ( BMNH, CMM, DEUA, MNHN, NHRS, NMPC, PBZT / MBC) : 12♂♂, 6♀♀, same data as holotype . 8♂♂, 7♀♀, “ Madagascar. Ex-prov. / Toliara. ca 10 km NNW / Tsivoky. 04 VI 2016. / Manuel leg. // S21°13’ / E45°20’ / Alt. 500m. Sandy pool / on bank of river Andranomanitsy / Makay massif” . 2♂♂, 1♀♀, “ Madagascar. Ex-prov. / Toliara. ca 10 km NNW / Tsivoky. 04 VI 2016 / Manuel leg. // S21°13’ E45°20’ / Alt. 500m. Spring, / alongside river Andranomanitsy / Makay massif” . 4♂♂, 1♀♀, “ Madagascar. Ex-prov. / Toliara. ca 10 km NW / Tsivoky 05 VI 2016. / Ramahandrison & Manuel leg. // S21°13’ E45°19’ / Alt. 650m. Lake above / natural dam in a canyon. / Makay massif” . 3♂♂, “ Madagascar. Ex-prov. / Toliara. ca 10 km NW / Tsivoky. 05 VI 2016 / Ramahandrison & Manuel leg. // S21°13’ E45°19’ / Alt. 650m. Slowly flowing / stream in a canyon, bottom / with much organic matter. / Makay massif” . 1♂♂, 2♀♀, “ Madagascar. Ex-prov. / Toliara. ca 10 km NW / Tsivoky. 05 VI 2016 / Manuel leg. S21°12’ E45°19’ // Alt. 700m. Quiet zone / alongside brook in deep / canyon, with masses of / orange deposit. Makay massif” . 1♂♂, 1♀♀, “ Madagascar. Ex-prov. / Toliara. ca 10 km NW / Tsivoky. 05 VI 2016 / Manuel leg. // S21°12’ E45°19’ / Alt. 620m. Pool full / of orange deposit. / Makay massif” . 11♂♂, 9♀♀, “ Madagascar. Ex-prov. / Toliara. ca 11 km NNW / Tsivoky. 05 VI 2016 / Manuel leg. // S21°13’ E45°19’ / Alt. 550m. Large pool / with masses of tree roots. / Makay massif” . 2♂♂, 4♀♀, “ Madagascar. Ex-prov. / Toliara. ca 9 km NNW / Tsivoky. 06 VI 2016 / Manuel leg. // S21°13’ E45°21’ / Alt. 600m. Small pools, / muddy-sandy bottom, / with tree roots, in canyon. / Makay massif” . 3♂♂, 2♀♀, “ Madagascar. Ex-prov. / Toliara. ca 10.8 km NW / Tsivoky. 07 VI 2016 / Manuel leg. // S21°13’ E45°19’ / Alt. 570m. Shallow / stream, under trees. / Makay massif” . 1♂♂, 1♀♀, “ Madagascar. Ex-prov. / Toliara. ca 10 km NW / Tsivoky. 07 VI 2016 / Manuel leg. // S21°13’ E45°19’ / Alt. 500m. Pool with / vegetation, alongside / river Andranomanitsy / Makay massif”. All paratypes with the respective printed red label .

Description of holotype. Habitus ( Fig. 3 ) oval-oblong, with lateral sides widely rounded, posteriorly rather strongly tapered to rounded apex; lateral outline continuous between pronotum and elytra; maximum body width at about 43% of total body length and about 31% of elytral length; dorsal surface evenly and moderately convex; in lateral view maximum height at about first third of total length.

Colouration. Dorsal surface of head rufo-testaceous. Pronotum rufo-testaceous, very narrowly darkened along posterior margin. Elytron with typical alluaudi- group colour pattern as in Fig. 3 ; brown longitudinal vittae weakly contrasting with testaceous background, anteriorly vaguely delimited, leaving rather wide basal area and humeral region entirely testaceous; pale stripes between dark longitudinal vittae irregularly interrupted. Ventral surface entirely rufo-testaceous ( Fig. 7 ). Antennae, palps, anterior and median legs testaceous; posterior legs rufo-testaceous.

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 narrowly 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, very weakly arcuate on each side of slightly produced, evenly 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. Pro- and mesotarsi not distinctly broadened, but with four transverse rows of small adhesive setae.

Aedeagus. Median lobe in lateral view as in Fig. 11 , in ventral view as in Fig. 18 ; parameres as in Figs. 27– 28 .

Females. Pro- and mesotarsi without ventral adhesive setae.

Variability. Specimens vary slightly in dorsal colour pattern, mainly with respect to homogeneity of colouration within the elytral brown longitudinal markings (in some specimens entirely pale brown, in others with gradually paler medial area enclosed in dark markings) and, to a lesser extent, degree of fragmentation of the pale interspaces between dark bands. However, the overall elytral pattern (notably, position of the anterior extremities of the dark bands) is highly stable among studied individuals.

Measurements. Holotype: TL = 3.9 mm, TL without head = 3.7 mm, MW = 2.1 mm, ratio TL/MW = 1.83. Paratypes: TL = 3.6–4.2 mm (3.91±0.17), TL without head = 3.4–4.0 mm (3.74±0.16), MW = 2.0– 2.4 mm (2.18±0.10), TL/MW = 1.71–1.94 (1.79±0.04).

Differential diagnosis. This species is close to L. alluaudi particularly with respect to the shape of the median lobe of aedeagus (compare Figs. 11, 18 and Figs. 12–15, 19–22 ) and parameres (compare Figs. 27–28 and Figs. 29–30 ). However, it differs from L. alluaudi by:

- slightly larger size ( L. alluaudi : specimens examined in this study, TL = 3.25–3.85 mm; Biström et al. 2015: TL = 3.4–3.9 mm),

- elytral colour pattern fainter, with pale area between anterior margin of elytron and anterior extremity of dark longitudinal markings distinctly broader, and with no basal dark marking in shoulder area (present in L. alluaudi ) (compare Fig. 3 and Fig. 4 ),

- ventral surface entirely testaceous (in L. alluaudi , metacoxal plates always largely dark brown to black; compare Fig. 7 and Fig. 8 ).

- median lobe in lateral view with basal piece proportionally larger and with keel (absent in southern populations of L. alluaudi ; compare Fig. 11 with Figs. 13–15 ), and in ventral view with apical quarter more strongly narrowed (compare Fig. 18 with Figs. 19–22 ).

In external morphology, L. makay shares with L. pseustes the entirely testaceous colouration of the ventral surface (all other known alluaudi -group species have the metacoxal plates darkened to a variable extent) and the rather faint elytral colouration pattern. However, in L. makay the dark elytral vittae end farther from the anterior margin of elytron. The median lobes of these two species have very different shapes (for L. pseustes , see Fig. 240–241 in Biström et al. 2015).

Habitat. This species was collected at an altitude range of 490– 670 m. It inhabits streams and stream-fed pools or ponds ( Figs. 47–49 ), generally surrounded by gallery forest. Most collecting sites were at least partly shaded by trees (only one fully sun-exposed site). The bottom consisted of sand (5/11 sites), sand together with siliceous stones or rock mass (3/11 sites), or clay (3/11 sites). Organic matter in the substratum was generally moderately abundant (8/11 sites); at two sites it was inconspicuous and on the contrary at one site (in which the species was not abundant) it formed a thick cover on the bottom. Water was very clear (except at one site) and the pH was moderately acidic. At all sites, helophytes were absent, and in the vast majority of sites (9/11) there was no submerged aquatic vegetation. Three sampling sites were characterised by strong development of orange deposits (e.g. Fig. 49 ) and at one site moderately abundant green filamentous algae were observed. All sites in which this species was sampled are situated in a well-preserved area with no significant signs of anthropogenic perturbation.

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

Derivatio nominis. This species is named after the type locality, the Makay massif in central-southern Madagascar. It is a noun in the nominative case standing in apposition.

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 47–52. Habitats of Laccophilus makay sp. nov. (47–49) and Laccophilus rakouthae sp. nov. (50–52). (47) Spring on sandy bank of river Andranomanitsy (Makay massif, 500 m); (48) Large pool with clear water, sandy bottom and masses of tree roots (Makay massif, 550 m). (49) Shadowed pool with sandy bottom and lots of orange deposit, beneath rock wall in a canyon (Makay massif, 540 m; type locality of L. makay); (50) Small uncultivated rice paddy field, in agricultural landscape (Ankaratra massif, Manjakatompo, 1,650 m); (51) Large eutrophic pond full of helophytes, surrounded by degraded forest (Ankaratra massif, Manjakatompo, Étang des Tilapia, 1,700 m; type locality of L. rakouthae); (52) Close-up view of the margin of the same pond.