Dexoris (s. str.) ruzzieri, Bocak, 2018

Bocak, Ladislav, 2018, Dexoris ruzzieri sp. nov. (Coleoptera: Lycidae), a new net-winged beetle from Ivory Coast, Zootaxa 4377 (1), pp. 138-142 : 139-141

Dexoris (s. str.) ruzzieri sp. nov.

( Figs. 1–10 )

Type material. Holotype. Male, " IVORY COAST, Mt. Tonkoul Peak , 7° 27' 15.2"N, 7° 38' 12.5"W, 12.–18. vii. 2015, general collecting, M. Aristophanous, P. Moretto, E. Ruzzier leg." The holotype is deposited in The Natural History Museum, London.

Diagnosis. There are only two Dexoris species occurring west of the Dahomey gap: D. insignis and C. ruzzieri sp. nov. These species differ in the coloration of antennomeres 3-7, which are dark brown in D. ruzzieri sp. nov. and lighter coloured in C. insignis . The pronotal carinae are parallel sided in the anterior third in D. ruzzieri sp. nov. ( Fig. 3 ) and divergent in D. insignis . Additionally, the carinae of D. ruzzieri sp. nov. are much stronger and bulbous in the part where inconspicuous vestiges of lateral carinae can be identified. This strengthened part of longitudinal carinae was observed also in the Cameroonian species D. tessmanni Bocak et Bocakova, 1988 which differs from D. ruzzieri by the short antennomere 4. Antennomeres 3 and 4 are similar in length in D. ruzzieri sp. nov. ( Fig. 1 ). All species known from Congolian wet forests can be identified using the identification key below. They differ in the colouration of antennae, the shape of the pronotum and male genitalia ( Bocak & Bocakova 1988).

Description. Male. Body small, 5.9 mm long, dorso-ventrally flattened and only slightly widened backwards, whole body light testaceous, only eyes black, antennomeres 3–6 dark brown, further antennomeres gradually lighter, terminal antennomeres light testaceous; whole abdomen dark brown ( Figs. 1–2, 7-10 ).

Head small, hypognathous, partly covered by pronotum ( Fig. 3 ); cranium with apparently prominent frontal part, antennal sockets prominent, separated by deep straight groove, antennal cavities wide ( Fig. 3 ), surface of cranium roughly punctured, very sparsely pubescent. Eyes small, with relatively large ommatidia, hemispherically prominent, frontal interocular distance 1.72 times eye diameter. Antennae 11-segmented, inserted laterally in antennal tubercles, reaching slightly behind half of elytral length, flat in cross section; scapus robust and pear-like, pedicel small, partly covered by scapus, much shorter than wide, antennomere 3 about ten times longer than antennomere 2, antennomere 4 similar in length to antennomere 3, subsequent antennomeres gradually shorter, antennomere 11 parallel-sided and long, all antennomeres with short dense pubescence ( Fig. 1–2 ).

Mouthparts with slender and quite long mandibles. Labrum small, simply rounded ( Fig. 4 ). Maxillae with setose mala; maxillary palpi 4-segmented, basal palpomere short, slender, about as long as wide, palpomeres 2 and 3 much wider, forming bulbous palpus with palpomere 4 which is projected apically in slender pointed process. Labial palpi tiny, slender.

Pronotum 1.7 times wider than long, anterior margin slightly projected in middle part, anterior angles obtuse, lateral margins bisinuate, posterior angles acute; pronotum with robust longitudinal carinae forming well-marked median areola attached to posterior margin in about one sixth of width of posterior margin, widely open anteriorly, distance between longitudinal carinae at frontal margin longer than distance between carinae and frontal angles, middle part of longitudinal carinae with vestiges of lateral keels, pronotal surface with fine deep irregular punctures, disc covered with sparse pubescence ( Fig. 3 ). Scutellum flat, slightly concave in anterior part, emarginate apically, distal processes slender, surpassing elytra, sparse setae in disc, dense short pubescence in distal part ( Fig. 3 ). Elytra fully developed ( Fig. 1 ), surpassing abdomen, tapering toward apex, without longitudinal or transverse costae, with small papillae each bearing single tiny seta, elytral surface completely covered with dense microsetae ( Fig. 5 ). Hind wings fully developed.

Legs with slender trochanters obliquely attached to femora, length of hind trochanters about 0.45 times femoral length, femora and tibiae slender, flattened, densely pubescent, tarsi pentamerous, tarsomeres slender, similar in width and length ( Fig. 1 ).

Abdomen wide, terminal sternite very small, deeply inserted in penultimate ventrite ( Figs. 7–10 ). Male genitalia with phallus only. Phallus about 9.8 times longer than wide in middle, gradually tapering and pointed apically, internal sac membranous, without any sclerotized structure ( Fig. 6 ).

Measurements. Body length 5.1 mm, width of humeri 1.54 mm, length of pronotum 0.85 mm, width of pronotum 1.46 mm, antennomeres - 1: 0.24 mm, 2: 0.05 mm, 3: 0. 52 mm, 4: 0.52 mm, frontal eye distance 0.55, maximum eye diameter 0.32 mm, length of the phallus 0.97 mm, width of the 6th sternite 1.39 mm, width of the 6th tergite 1.10 mm.

Etymology. The specific name is proposed in honour of Enrico Ruzzier, one of collectors of the type specimen.

Figures

FIGURES 1–10. The male of Dexoris ruzzieri sp. nov. (holotype) 1. General appearance 2. Apical antennomeres 3. Head and prothorax, dorsally 4. Head and prothorax, ventrally 5. Middle part of the right elytron, detail 6. Phallus 7. Abdomen, ventrally 8. Sixth abdominal sternite 9. Sixth abdominal ventrite 10. Terminal abdominal segments, ventral view. Scale bars = 1.0 mm.