Copelatus marginipennis (Laporte, 1835)

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

publication ID	https://dx.doi.org/10.3897/zookeys.869.33997
publication LSID	lsid:zoobank.org:pub:B7C88A64-C06E-4B67-A352-F2F9C8FB0D1C
persistent identifier	https://treatment.plazi.org/id/C9FE8EA4-86D5-57DF-A5B1-A38A9F232743
treatment provided by	ZooKeys by Pensoft
scientific name	Copelatus marginipennis (Laporte, 1835)
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Treatment

Copelatus marginipennis (Laporte, 1835) View in CoL Figs 5A View Figure 5 , 8A View Figure 8

Colymbetes marginipennis Laporte, 1835: 102.

Copelatus aldabricus J. Balfour-Browne, 1950: 368 syn. nov.; TL: Seychelles, Aldabra Islands.

Copelatus aldabricus var. simplex Guignot 1952: 28 syn. nov.; TL: Madagascar.

Type locality.

Senegal [possibly mislabelled].

Type information from original description.

housed in Buquet collection and originating from Senegal; of aldabricus : based on male (holotype), J.C. Fryer collection, collected 1908-9 from Aldabra; of simplex : based on male and female syntypes from Madagascar without further locality data.

Type material studied.

Additional material studied.

Diagnosis.

Copelatus marginipennis is distinguished from all other Malagasy Copelatus except C. pulchellus and C. mahajanga by the presence of six discal elytral striae and a broadly oval body shape. Copelatus marginipennis is most easily separated by the distinct shape of the male penis in lateral view ( Fig. 5A View Figure 5 ). Copelatus pulchellus (from Madagascar) lacks a transverse testaceous band basally on the elytra and females of C. marginipennis can usually be distinguished from C. mahajanga by the normally narrower testaceous band, a longer first elytral stria, and a broader body shape.

Description.

Body length 5.2-6.6 mm. Body shape oval, rather convex and attenuate posteriorly, dark brown to brown ferrugineous. Head, pronotum and elytra in the same dark brown ferrugineous, covered with fine dense punctation. Lateral sides of pronotum more brownish, with short strioles and the widest striolate area in the posterior corners. Elytra dark brown to brown ferrugineous, with a testaceous transverse band at base ( Fig. 8A View Figure 8 ). Six clearly impressed elytral striae present and one submarginal: first stria abbreviated and slightly shorter, starting at approx. 1/7th posterior of elytral base, second to sixth full length, and submarginal stria starting at approx. the middle; all striae approaching the apex of elytron except the sixth, which is abbreviated posteriorly and a little shorter. Sometimes, the first and second elytral striae, like fifth and sixth, unite posteriorly. Elytral surface covered with dense punctures.

Ventral side brownish to ferrugineous, metacoxa with microsculpture, densely and finely punctate. Metacoxa and abdominal ventrites striolate. Prosternal process rather short and spear-shaped, medially only weakly raised and rounded. Lateral parts of metaventrites rather broad. Metacoxal lines short and rather strongly diverging anteriorly. Antennae and palps both in the same brown colour. Pro- and mesothoracic legs brown ferrugineous. Metathoracic legs dark brown ferrugineous.

Male: Protibia strongly angled basally and expanded in apical two thirds. Penis in ventral view with a small preapical tooth on right side; in lateral view very characteristic with a subbasal dorsal knob, and post-middle with a deep ventral invagination ( Fig. 5A View Figure 5 ).

Females from Madagascar usually with elytral striolation rather weak and restricted to outer intervals, but rarely the elytra are entirely and distincly striolate. Females on average smaller than males.

Distribution.

Endemic to the western Indian Ocean islands as far as is modernly known, but the 1835 type locality of the original description and labels read “Senegal”, which indicates either mislabeling or that the species in fact also occurs on continental Africa. Known from Madagascar, Reunion, Comores, Seychelles, and Aldabra Island ( Gomy 2016). Widespread in Madagascar and recorded from Montagne d’Ambre NP and Masoala NP in the north and northeast to Kirindy in the southwest ( Fig. 11A View Figure 11 ), but apparently lacking from most of the central plateau. It can probably show up anywhere around the island below 1000 m in altitude.

Habitat and ecology.

This is a lowland species that seems to be most common in the deciduous western parts of Madagascar. It was common in the newly designated protected areas of Mahavavy Kinkony when we visited it in 2009. In the deciduous forest biome it has been recorded from Kirindy in the south to Ankarana NP in the north. The species seems to be a generalist and can as well show up on lowland humid east coast and at midaltitudes up to at least 1000 m. It is an apt flier collected with light traps and often in very temporary and small shallow pools including water-filled wheel tracks. Found in all kinds of temporary pools, as well as in streams and in residual pools in dried-up riverbeds. It occurred sympatrically with C. mahajanga in Betsabora river near Moramanga and at a 22W black light trap by a forest pool in Ankarafantsika NP.

Comments.

Copelatus aldabricus was described by J. Balfour-Browne (1950) from Aldabra Island in the Seychelles. Guignot (1952) named a non-striolated female variety from Madagascar as var. simplex , and again in 1961 as var. aequabilis (non-available infrasubspecific name) from Andranofotsy (E of Maroantsetra NE Madagascar), and stated (1961) that females of C. aldabricus are normally striolated, but that on Madagascar the non-striolated var. aequabilis is most common or even ubiquitous. We have found at least one female on Madagascar (from Masoala NP) with the elytra entirely striolated (the “normal” variety sensu Guignot 1961), but indeed the form where striolation is rather weak and only at outer elytral intervals is most common. Guignot’s (1961) distinction between female forms either having or lacking strioles is, however, a simplification. All females we have seen have at least some weak tendencies of striolation on outer intervals and the extent can vary significantly between individuals.

Copelatus marginipennis (Laporte, 1835) has been treated as a junior synonym of Copelatus pulchellus Klug, 1834 since Aubé (1838). We discovered the type material of Laporte´s C. marginipennis in MNHN, Paris. This could be identified based on a folded blue label bearing the information " Copelatus marginipennis Buquet, pulchellus var Aubé, h. in Senegal, D. Buquet", which fits perfectly the description by Laporte (1835). The genitalia of this male show without any doubt that it is a synonym of the younger name C. aldabricus and not of C. pulchellus . The name marginipennis has to our knowledge not been used as a valid name after 1899, fulfilling the first of the two criteria for protecting a younger currently used synonym from an older available name (ICZN 23.9.1.1). However, Copelatus aldabricus is a relatively recent name from a region with a low-intensity taxonomic research and we do not believe it fulfils the second criteria of at least 25 papers published by at least ten authors in the immediately preceding 50 years and encompassing a span of not less than ten years (ICZN 23.9.1.2). Therefore it is not justifiable to protect the younger synonym C. aldabricus and the older C. marginipennis is therefore brought back as the valid name of this species. We designate the discovered syntype of Colymbetes marginipennis Laporte, 1835 in the MNHN collection as lectotype to preserve stability of the name. At the same time as this type specimen was discovered, also a likely “type” specimen of the nomen nudum Copelatus fimbriolatus Dejean, 1837 from "Ile de France" [= Mauritius] was found with the same type of blue folded label (see supplementary file 1: NHRS-JLKB000065420). This nomen nudum is currently considered a synonym of C. pulchellus Klug (Nilsson and Hajek 2018). Unfortunately, it is a female specimen, which is why its identity cannot be established with certainty, but it is more likely identical with C. marginipennis since C. pulchellus is not yet known from any of the Mascarene Islands ( Gomy 2016).

Kingdom	Animalia
Phylum	Arthropoda
Class	Insecta
Order	Coleoptera
Family	Dytiscidae
SubFamily	Copelatinae
Genus	Copelatus

Copelatus marginipennis (Laporte, 1835)

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