Nephus apolonia sp. nov. is similar to N. voeltzkowi and N. oblongosignatus but differs by the size and shape of the spots and the pattern of genitalia.

Male. Length 1.69 mm, width 1.2 mm. Body oval, oblong, with short fine whitish pubescence. Integument of pronotum, scutellar shield and elytra black. Elytra with one yellowish longitudinal spot on each elytron (Fig. 5A, C). Pronotum black, antero-lateral border dark brown (Fig. 5A, D). Head dark brown, antennae and mouthparts yellowish (Fig. 5B, D). Meso- and metaventrite light brown. Epipleuron light brown, without excavations to receive femora. Legs with coxae and femora dark brown, tibiae and tarsi light brown (Figs 1L, 5B, D). Abdomen light brown (Fig. 5E); postcoxal line incomplete (Fig. 1P), and last ventrite emarginate (Fig. 5F).

Genitalia with tegmen, penis guide, phallobase and parameres symmetrical. Penis guide shorter than parameres, sharp at apex (Fig. 5I, J). Parameres articulated with phallobase, distant from each other, strongly widened at apex, with short bristles along parameres (Fig. 5I, J). Penis sclerotized, J-shaped, with sharp apex, penis capsule T-shaped and elongated (Fig. 5G, H).

Female. Length 1.88 mm, width 1.30 mm. Similar to male. Genitalia with coxites longer than wide, subtriangular, 3.0× longer than wide; stylus mamiliform with long bristles (Fig. 5L). Spermatheca heavily sclerotized, slightly arched, not very striated, and marked by one strong constriction in the middle, with sharp base and rounded apex (Fig. 5K).

This species is named after an early name of Reunion Island, mentioned as “Santa Apolonia” on the Portolan charts (nautical charts) from the XVI^th century (GENUNG, 2017).

Reunion Island: from a laboratory rearing (Laboratoire Evolution & Diversité Biologique, Université Toulouse III) initiated from field material collected in December 2013 in Manapany-les-Bains and Étang-Salé.

Holotype male, pinned, with genitalia in a separate microvial. Original label: “Reunion Island, 1 specimen [MNHN]”; “HOLOTYPE/ Nephus apolonia Magro and Almeida” [red label]. Paratypes. The following specimens are designated as paratypes with labels: “same data as for holotype”. “PARATYPE/ Nephus apolonia Magro and Almeida” [yellow label]: “Reunion Island, 2 specimens [MNHN, DZUP]; “Reunion Island, 1 specimen [MNHN]; “Reunion Island, 1 specimen [DZUP]; “Reunion Island, 1 specimen [MNHN]; “Reunion Island, 1 specimen [DZUP]; “Reunion Island, 2 specimens [DZUP, MNHN]; “Reunion Island, 1 specimen [DZUP].

Reunion Island: L’Étang-Salé, Le Trou d’eau (21°16'54.2"S, 55°21'39.7"E); Saint-Denis, Saint-Bernard (20°52'58.36"S, 55°23'50.19"E); Saint-Louis, Etang du Gol (21°17'20.9"S, 55°23'16.1"E); La Possession, Ravine à Malheur (20°54'03.5"S, 55°22'32.1"E); Saint-Pierre, CIRAD (21°19'13.8"S, 55°29'6"E); L’Étang-Salé, ARDA (21°17'05.6"S, 55°22'38.1"E) and Saint-Joseph, Langevin (21°22'53.4"S, 55°38'48.4"E).

Nephus apolonia sp. nov. has apparently been misidentified as N. voeltzkowi until now. We verified that this was the case for specimens captured by the Insectarium de La Réunion. Poussereau et al. (2018) included three species for Reunion Island. In that work, N. voeltzkowi is reported with large variation and distribution. It could be possible that the specimens identified by Poussereau et al. (2018) as N. voeltzkowi included the Nephus apolonia sp. nov. described here.

The mitochondrial genome of one specimen of Nephus apolonia is deposited in Genbank under accession number MN164644. Genetic distances based on the COI sequences between N. apolonia and other Nephus species confirm that N. apolonia is different from the other species, as all distances are within the same range (i.e., 0.13–0.17) (Table 2). In the phylogenetic tree reconstructed from 14,867 pb of aligned mitochondrial genomes (Fig. 6), most nodes, including N. apolonia, were supported by high bootstrap values.