Copelatus malavergnorum Manuel & Ramahandrison, 2022

Ramahandrison, Andriamirado Tahina, Rakouth, Bakolimalala & Manuel, Michael, 2022, The aquatic Adephaga of the Makay, central-western Madagascar, with description of two new diving beetle species (Coleoptera, Gyrinidae, Haliplidae, Noteridae, Dytiscidae), ZooKeys 1127, pp. 1-60 : 1

Copelatus malavergnorum Manuel & Ramahandrison sp. nov.

Figs 3A , 4A-D

Type locality.

Madagascar, Toliara province, Malaimbandy municipality, Makay massif (northern part), ca. 20 km WSW Tsimazava, ca. 20°45'S, 45°31'E, altitude ca. 360 m a.s.l.

Type material.

Holotype ♂: "Madagascar. Ex-prov. Toliara / Makay massif, ca. 20 km / WSW Tsimazava / 20°44'42"S, 45°31'35"E / 11.IV.2018. Ramahandrison leg. [pr.] // Alt. 364 m. Blind channel / connected with the Sakapaly / River, with orange masses of / iron bacteria on the bottom. [pr.] // Holotype / Copelatus malavergnorum sp. nov. / Manuel & Ramahandrison, 2022 [red, pr.]" (MNHN).

Diagnosis.

This species belongs to the Copelatus irinus -group and the C. insuetus -complex (revised in Ranarilalatiana et al. 2019). It differs from C. insuetus Guignot, 1941 by: smaller size; narrower and more parallel habitus, dorsally flatter; broader pronotum with lateral margins posteriorly more parallel; colour of dorsal and ventral surfaces paler; testaceous basal band of elytron broader; discal stria I on elytron more weakly impressed; strioles on postero-lateral region of pronotum and on metacoxal plate sparser; metacoxal lines shorter; medial lobe of aedeagus in lateral view with apical half of more even width and with apex less narrowly acute, in ventral view distinctly more evenly narrowed from base to apex. This species is externally similar to C. vokoka Ranarilalatiana & Bergsten, 2019, but differs by: habitus narrower and more parallel, dorsally flatter; pronotum broader and with lateral margins posteriorly more parallel; discal stria I on elytron more weakly impressed and anteriorly more strongly abbreviated; strioles on pronotum and metacoxal plates much sparser; metacoxal lines shorter; median lobe of aedeagus in lateral view with apical half broader and less strongly arcuate, in ventral view with apex twisted to the left (straight in C. vokoka ). Finally, it differs from C. kely Ranarilalatiana & Bergsten, 2019 notably by the lateral margins of pronotum anteriorly more strongly convergent, the lateral margins of elytra posteriorly more strongly attenuated, the median lobe in lateral view with the distal half much thicker and the dorsal outline less strongly curved, and in ventro-apical view much more gradually narrowed (in C. kely abruptly narrowed at ca. midlength from base to apex), subapically thicker and less strongly bent to the left.

Description of holotype.

Body elongated and parallel-sided (Fig. 3A ), weakly convex dorsally. Pronotum broad (ratio between maximum width of pronotum and maximum body width ~ 0.97), with sides posteriorly subparallel. Head rufo-testaceous with only very faint infuscation between eyes. Ratio between interocular distance and maximum width of head ~ 0.66. Pronotum rufo-testaceous as head, with weak medial infuscation. Elytra brown with broad testaceous basal band; testaceous band very diffusely transitioning into darker colour posteriorly (Fig. 3A ).

Elytra with six discal and one submarginal striae. Stria I very weakly impressed. Striae I, V, and VI abbreviated anteriorly. Submarginal stria very weakly impressed, starting slightly before elytron midlength. Head, pronotum and elytra with fine reticulation and fine punctation. Posterolateral region of pronotum with few short and weakly impressed strioles.

Ventral side rufo-testaceous, slightly darker laterally on metacoxal plate and on abdominal ventrites. Metacoxal plates with sparse and very fine short strioles; visible abdominal ventrites I-III with denser and longer very fine strioles. Prosternal process rather short and broad, with blunt apex. Metacoxal lines rather long, ending anteriorly at quite small distance from posterior margin of metaventrite, diverging anteriorly.

Appendages: Antennae, palps and legs testaceous. Antennae particularly long (Fig. 3A ). First three pro- and mesotarsomeres widened and ventrally equipped with suction cups; number of suction cups per articles (I-III) 7:4:4 on both pro- and mesotarsus. Protibia at base narrow, with bisinuate ventral margin, distally strongly broadened. Pro- and mesotarsal claws unmodified.

Median lobe and parameres as in Fig. 4A-D .

Female. Unknown.

Measurements.

TL 4.2 mm, TL without head 3.7 mm, MW 1.8 mm, ratio TL/MW 2.34.

Etymology.

This species is dedicated to the Malavergne family (Dominique, Catherine, Clémence, Jacques, and Laurence, Marie-José) in recognition of their constant help and support to the first author during his PhD thesis. The species epithet is a name in the genitive plural.

Distribution.

So far known only from northern Makay in Madagascar.

Habitat.

The external morphology of this species (very narrow and parallel habitus, broad pronotum, pale colour, long antennae) suggests that it might be a semi-subterranean species. The habitat where the single specimen was found (MAK-44C) was a blind channel connected to River Sakapaly, in northern inner Makay. There was no apparent water flow but the bottom was covered with conspicuous orange masses of iron bacteria, which might be an indication of slow water seepage from underground. The substratum was sandy with moderate amount of decaying vegetal material and the water was red-brown coloured. This water body was fully shaded under trees in forest. There was no vegetation in the water but the surrounding forest floor displayed a typical hygrophilic vegetation of Poaceae , Cyperus and Pandanus . Other species of aquatic Adephaga (all Dytiscidae ) sampled at the same site: Copelatus polystrigus , C. vigintistriatus , Hydrovatus acuminatus Motschulsky, 1860, Laccophilus makay , Methles sp. Ma1, M. sp. Ma5, Neohydrocoptus sp. Ma3, and Pachynectes sp. Ma1.

Figures

Figure 3. Habitus in dorsal view. Scale bars: 2 mm A Copelatus malavergnorum sp. nov. (holotype) B Copelatus zanabato sp. nov. (holotype).

Figure 4. Male genitalia. Scale bars: 200 µm A-D Copelatus malavergnorum sp. nov. (holotype) E-H Copelatus zanabato sp. nov. (holotype) A, E Median lobe of aedeagus in right lateral view B, F Median lobe of aedeagus in ventral view C, G Median lobe of aedeagus in left lateral view D, H Left paramere.