Copelatus zanabato 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 zanabato Manuel & Ramahandrison sp. nov.

Figs 3B , 4E-H

Type locality.

Madagascar, Toliara province, Malaimbandy municipality, Makay massif (northern part), ca. 21 km W of Tsimazava, ca. 20°42'S, 45°30'E, altitude ca. 430 m a.s.l.

Type material.

Holotype ♂: "Madagascar. Ex-prov. Toliara / Makay massif, ca. 21 km / W Tsimazava / 20°42'10"S, 45°30'18"E [pr.] // 12.IV.2018. Ramahandrison leg. / Alt. 433 m. Pool in a / very narrow and dark / canyon. [pr.] // Holotype / Copelatus zanabato sp. nov. / Manuel & Ramahandrison, 2022 [red, pr.]" (MNHN). Paratypes: 1 ♀: same as holotype. 1 ♂: "Madagascar. Ex-prov. Toliara / Makay massif, ca. 20 km / WSW Tsimazava / 20°43'54"S, 45°31'10"E / 14.IV.2018. Ramahandrison leg. [pr.] // Alt. 437 m. Small / pond in a canyon at / Ampasimaiky [pr.]" (CMM). Both paratypes with respective red label.

Diagnosis.

This species belongs to the Copelatus erichsonii -group. It is externally rather similar to C. acamas , from which it differs by distinctly smaller size; habitus narrower with sides more parallel, dorsally much flatter; discal stria IX on elytron more strongly abbreviated anteriorly; strioles on pronotum surface sparser and much more weakly impressed; shape of median lobe of aedeagus very different. Among Copelatus species known from Madagascar, the aedeagus of C. zanabato sp. nov. is most similar to that of C. andobonicus . From the latter, the new species differs by: habitus narrower with sides more parallel, dorsally much flatter; pronotum paler and elytra with darker linear colouration following the striae much less contrasted with respect to paler background; strioles on pronotum surface denser, present on whole surface (in C. andobonicus almost without striae in anterior disk region); median lobe of aedeagus in lateral view with broad flat protuberance on ventral side ca. halfway between base and apex (in C. andobonicus with much smaller protuberance at ca. basal third) and apical third much broader, in ventral view with apical region much broader and evenly narrowed, twisted on the left farther from apex.

Description of holotype.

Body shape elongate oval, with sides subparallel (Fig. 3B ), dorsally weakly convex. Pronotum sides evenly curved and converging from posterior angle. Ratio between maximum width of pronotum and maximum body width ~ 0.90. Head uniformly light rufo-testaceous. Ratio between interocular distance and maximum width of head ~ 0.68. Pronotum medially rufous, laterally colour becoming gradually rufo-testaceous. Elytra light chestnut brown, with darker linear colouration along striae (Fig. 3B ).

Elytra with ten well-impressed discal and one submarginal striae. Stria IX abbreviated anteriorly. Striae I and II diverging anteriorly. Submarginal stria starting slightly before elytron midlength, fragmented anteriorly. Head, pronotum and elytra with fine reticulation and fine punctation. Whole surface of pronotum with rather dense, short and fine strioles, in medial disk region strioles even finer.

Ventral side uniformly rufo-testaceous. Metacoxal plates with moderately impressed short strioles; visible abdominal ventrites I-III with denser and longer very fine strioles. Prosternal process short and broad, with rounded apex. Metacoxal lines short, ending anteriorly at large distance from posterior margin of metaventrite, moderately diverging anteriorly.

Appendages: Antennae, palps, forelegs and midlegs testaceous, hindlegs rufo-testaceous. First three pro- and mesotarsomeres widened and ventrally equipped with suction cups; number of suction cups per article (I-III) 7:4:4 on both pro- and mesotarsus. Protibia at base shortly narrow, with shallow protuberance along ventral margin, distally broadened. Pro- and mesotarsal claws unmodified.

Median lobe and parameres as in Fig. 4E-H .

Female. Strioles on pronotum surface denser. Pro- and mesotarsomeres and protibia unmodified.

Measurements.

Holotype: TL 6.35 mm, TL without head 5.7 mm, MW 2.9 mm, ratio TL/MW 2.20. Paratypes: TL 6.55-6.8 mm, TL without head 5.9-6.1 mm, MW 3.0-3.1 mm, ratio TL/MW 2.17.

Variation.

In the male paratype, strioles on pronotum are longer and more deeply impressed than in the holotype, and the metacoxal lines are slightly longer. In the female paratype, the elytral stria V is slightly abbreviated anteriorly.

Etymology.

The species name literally means "son of the rock" in Malagasy. It is an invariable name standing in apposition.

Distribution.

So far known only from northern Makay in Madagascar.

Habitat.

This species was collected at two sites located in two nearby canyons in northern inner Makay. Two specimens were sampled at site MAK-46, an isolated pool (~ 1 m × 3 m) on the bottom of a narrow and dark canyon, and one specimen at site MAK-50, a stagnant temporary pond (~ 3 m × 7 m) situated in a wider canyon and in a more open environment. Both habitats were characterised by sandy bottom with some plant debris, absence of visible inflow / outflow, somewhat turbid water and no vegetation. Other species of aquatic Adephaga (all Dytiscidae ) sampled at the same sites: Copelatus acamas , C. ruficapillus , Cybister operosus Sharp, 1882, Hydaticus sobrinus Aubé, 1838, Hyphydrus separandus Régimbart, 1895, Laccophilus makay , Pachynectes sp. Ma1, and P. sp. Ma4.

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.