Copelatus vokoka Ranarilalatiana & Bergsten
Ranarilalatiana, Tolotra, Raveloson Ravaomanarivo, Lala Harivelo & Bergsten, Johannes, 2019, Taxonomic revision of the genus Copelatus of Madagascar (Coleoptera, Dytiscidae, Copelatinae): the non- erichsonii group species, ZooKeys 869, pp. 19-90: 19
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|Copelatus vokoka Ranarilalatiana & Bergsten|
Ivohibe Special Reserve [22.456683S, 46.956283E] [Madagascar, Ihorombe region, Ivohibe district]
Fianarantsoa. Ihorombe: Ivohibe: -HT♂ (GP) ( NHRS): // NHRS-JLKB | 000010849 // Madagascar: Fianarantsoa: Ihorombe: R.S. | Pic d’Ivohibe Corridor: at the confluence of | two rivers Inganga and Anefitany: | S22.456683; E046.956283; 874 m; 09.XII.2013 | GB Nets & sieves: forest pools with dead | leaves, Leg. J.H. Randriamihaja & | T. Ranarialalatiana: Field# MAD13-55 // Holotype | Copelatus vokoka sp. nov. | Det. Ranarilalatiana | & Bergsten, 2019 // Paratypes: -6♂ (GP), 2♀, 16 ex. (6♂, 10♀) (Alc.) ( NHRS, NHMUK, DEUA & PBZT/MBC): // NHRS-JLKB | 000010850-4, 10857, 65735-6, 10855(Alc.) // Madagascar: Fianarantsoa: Ihorombe: R.S. | Pic d’Ivohibe Corridor: at the confluence of | two rivers Inganga and Anefitany: | S22.456683; E046.956283; 874 m; 09.XII.2013 | GB Nets & sieves: forest pools with dead | leaves, Leg. J.H. Randriamihaja & | T. Ranarialalatiana: Field# MAD13-55 // Paratype | Copelatus vokoka sp. nov. | Det. Ranarilalatiana | & Bergsten, 2019 // -1♂ (GP), 1♀, 3♀ (Alc.) ( NHRS): // NHRS-JLKB | 000010512-3, 10782(Alc.) // Madagascar: Fianarantsoa: Ihorombe: | R.S. Pic d’Ivohibe Corridor: The | confluence of rivers Inganga and | Anefitany: S22.457283; E046.95535; 870 m, | 09.XII.2013, GB Nets & sieves: big | muddy pool, Leg. J.H. Randriamihaja & | T. Ranarialalatiana: Field# MAD13-57 // Paratype | Copelatus vokoka sp. nov. | Det. Ranarilalatiana | & Bergsten, 2019 // Fianarantsoa. Vatovavy Fitovinany: Ifanadiana: -1♂ (GP), 4♂, 11♀ (coll. Michaël Manuel, Paris, NHRS): // Madagascar. Ex-prov. Fiana- | rantsoa. ca. 3.3 km WSW | Ranomafana. 28 XII 2017. | Ramahandrison & Manuel leg. // 21°16'05"S, 47°25'28"E Alt. 993 m. | Shallow shaded pond with large | quantity of dead tree leaves and | some Poaceae, in forest. | Ranomafana NP. // Coll. | M. Manuel | Paris // Paratype | Copelatus vokoka sp. nov. | Det. Ranarilalatiana | & Bergsten, 2019 //
Body shape slightly shorter, less elongate and slightly more oval than C. insuetus , and eyes smaller. Elytral striae more deeply impressed and intervals therefore slightly more convex ( Fig. 9B View Figure 9 ). Penis shape in lateral view gently curved from base to apex ( Fig. 6C View Figure 6 ), lacking the defined “shoulder” of C. insuetus and C. kely . Penis more or less straight in ventral view, which separates the species from all other in the insuetus complex.
Body length 3.9-4.5 mm. Body shape elongate oval, but slightly less elongate compared with C. insuetus . Head rufotestaceous with only a faint suggesstion of an M-shaped infuscation between eyes. Pronotum rufotestaceous as the head, with weak medial infuscation Elytra dark brown, with testaceous band at base. Testaceous band generally broader and more diffusely transitioning into the darker elytral colour posteriorly ( Fig. 9B View Figure 9 ) compared with C. insuetus . Antennae, palps and legs testaceous.
Elytra with six discal and one submarginal striae. First to fourth more or less full length, fifth and sixth slightly abbreviated anteriorly; submarginal stria starting approximately one half to one third from base. Striae more deeply impressed and intervals therefore slightly more convex compared to C. insuetus . Head, pronotum, and elytra microreticulate and finely micropunctate. Pronotum extensively and coarsely striated on posterior surfaces, although reduced posteromedially. On some specimens striolation covers most of pronotum, also on anterior surfaces, but is reduced medially.
Ventral side entirely testaceous except metacoxal plate which is variably infuscated, especially laterally in some individuals; metacoxa and abdominal sternites II–IV striolate. Prosternal process with a slightly more pointed apex than in C. insuetus and C. kely , and lateral parts of metaventrite not as broad. Metacoxal lines long and not strongly diverging, as in C. kely .
Male: first three pro- and mesotarsomeres widened, ventrally equipped with suction cups (same constellation as in C. insuetus ). Protibia modified, bisinuate and angled basally and broadened distally. Pro- and mesotarsal claws unmodified. Penis long, thin and simple; apex in ventral view straight and not leftturned; in lateral view rather evenly arched, lacking the distinct “shoulder” characteristic of C. insuetus but with a different type of postmedial and preapical suggested humps in the curvature. Apex in lateral view also broder closer to apex. Apex in left lateral view with a dorsal ridge crossing posterior dorsal margin but at a more acute angle ( Fig. 6C View Figure 6 ) compared with C. insuetus . Preapically left side with fine transverse ridges. Right lateral and ventral side with fine longitudinal microsculpture but not forming coarse sulci as in C. insuetus . Parameres as in Figure 6C View Figure 6 .
Female: very faint to no striolation on outer elytral intervals in the series from Ivohibe. All females from Ranomafana NP were densely striolated over the entire elytral surface except at the apical part, and entire pronotum. Density of striation approx. 5-8 striae in breadth across each elytral interval.
Vokoka is a Malagasy adjective for curvature, also used for an old person with a hunched back. Here it refers to the even curvature of the male aedeagus in lateral view where the even curvature sets it apart from C. insuetus . It is a non-latinised adjective.
Known from the mountainous escarpment of southeastern Madagascar at Ivohibe Special Reserve and Ranomafana NP ( Fig. 12B View Figure 12 ). Our sampling is rather scant in the humid forests south of Ivohibe, for instance down to Andohahela NP so it is possible the species distribution continues further south.
Habitat and ecology.
We collected this species in 2013 from forest pools with dead leaves next to streams at the Ivohibe reserve in pristine humid forest at an altitude of 870 m. The reserve of Pic d’Ivohibe was established in 1964 and is managed through collaboration between Madagascar National Parks, local people associations, and other partners. During our visit in 2013, there were little signs of degradation except at the entrance and at the west edge of the reserve. Local people sometimes take zebu cattle with them on a path through the forest. At a larger scale zebu excrement could influence freshwater quality and species assemblages through eutrophication, but there were no signs of this inside the intact pristine forest. In Ranomafana NP it was collected in a shallow clear-water shaded forest pond with large quantity of dead tree leaves and some Poaceae (M. Manuel pers. comm.).
Copelatus vokoka sp. nov. falls in the irinus group, based on the number of elytral striae. The new species is most closely related to C. ankaratra according to the mitochondrial gene CO1 and belongs to the C. insuetus species complex on Madagascar.
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