Diomus guilavoguii Duverger, 1994

Diomus guilavoguii Diomus guilavoguii Duverger, 1994: 121.

Materials

Type status: Other material. Occurrence: recordedBy: Jiamin Zhuang; individualID: SCAU (E) 17572; individualCount: 1; sex: male; lifeStage: adult; behavior: running; occurrenceID: 414A66E3-1DDC-5F13-A1DC-68F59BDD3139; Taxon: scientificName: Diomus guilavoguii; class: Insecta; order: Coleoptera; family: Coccinellidae; genus: Diomus; Location: country: China; countryCode: CHN; stateProvince: Guangdong; municipality: Guangzhou; locality: South China National Botanical Garden; verbatimElevation: 47.9 m; decimalLatitude: 23.180592; decimalLongitude: 113.366531; Identification: identifiedBy: Xiaosheng Chen; dateIdentified: 10-12-2022; identificationReferences: Duverger 1994; Event: samplingProtocol: observe; year: 2022; month: 9; day: 2; Record Level: institutionID: South China Agricultural University; institutionCode: SCAU; basisOfRecord: Preserved Specimen Type status: Other material. Occurrence: recordedBy: Jiamin Zhuang; individualID: SCAU (E) 17573; individualCount: 1; sex: female; lifeStage: adult; occurrenceID: 660BFF3A-1B43-5FF4-8786-652803487BBC; Taxon: scientificName: Diomus guilavoguii; class: Insecta; order: Coleoptera; family: Coccinellidae; Location: country: China; countryCode: CHN; stateProvince: Guangdong; municipality: Guangzhou; locality: South China National Botanical Garden; verbatimElevation: 47.9 m; decimalLatitude: 23.180592; decimalLongitude: 113.366531; Identification: identifiedBy: Xiaosheng Chen; dateIdentified: 10-12-2022; identificationReferences: Duverger 1994; Event: samplingProtocol: observe; year: 2022; month: 9; day: 23; Record Level: institutionID: South China Agricultural University; institutionCode: SCAU; basisOfRecord: Preserved Specimen Type status: Other material. Occurrence: recordedBy: Mingjie Tang; individualCount: 13; sex: 6 male, 2 female, 9 unsexed specimens; lifeStage: 8 adult, 4 pupa, 5 larvae; occurrenceID: 5D4D546E-BD3F-5241-A8E4-A4CA13770E31; Taxon: scientificName: Diomus guilavoguii; class: Insecta; order: Coleoptera; family: Coccinellidae; Location: country: China; countryCode: CHN; stateProvince: Guangdong; municipality: Guangzhou; locality: Campus of South China Agricultural University; verbatimElevation: 33.4 m; decimalLatitude: 23.162782; decimalLongitude: 113.355362; Identification: identifiedBy: Xiaosheng Chen; dateIdentified: 10-12-2022; identificationReferences: Duverger 1994; Event: samplingProtocol: observe; year: 2022; month: 9; day: 27; Record Level: institutionID: South China Agricultural University; institutionCode: SCAU; basisOfRecord: Preserved Specimen Type status: Other material. Occurrence: recordedBy: Xiufeng Xie; individualCount: 10; sex: 9 male, 1 female; lifeStage: adult; occurrenceID: 297D0151-D750-534B-AA7A-BB0B3C8411CA; Taxon: scientificName: Diomus guilavoguii; class: Insecta; order: Coleoptera; family: Coccinellidae; Location: country: China; countryCode: CHN; stateProvince: Guangdong; municipality: Guangzhou; locality: Campus of Guangdong AIB Polytechnic College; verbatimElevation: 22.5 m; decimalLatitude: 23.284552; decimalLongitude: 113.612518; Identification: identifiedBy: Xiaosheng Chen; dateIdentified: 07-23-2023; identificationReferences: Duverger 1994; Event: samplingProtocol: observe; year: 2023; month: 7; day: 2; Record Level: institutionID: South China Agricultural University; institutionCode: SCAU; basisOfRecord: Preserved Specimen

Description

Adult. TL: 1.53-1.54 mm, TW: 1.16-1.21 mm, TH: 0.57-0.63 mm, TL/TW: 1.27-1.32, PL/PW: 0.31-0.32, EL/EW: 1.00-1.03, HW/PW: 0.61-0.65, PW/EW: 0.73.

Male: Body oval, weakly convex; usually winged; dorsum uniformly hairy. Head transverse, dorsally not covered by pronotum (Fig. 2 a). Winged. Head yellowish-brown; elytra brownish, with the apex yellowish. Dorsum evenly covered by dense, whitish pubescence with hairs not forming distinct patterns, but mostly pointing posteriorly (Fig. 3 a-c). Eye very large, finely facetted, weakly emarginated and moderately separate on vertex; inner orbits converging anteriorly; frons twice width of eye (Fig. 3 b). Antennae of the type specimens are composed of 11 antennomeres, whereas those from China have only 10 antennomeres; antennomere 3 about 2.2 times as long as 4; antennal club consisting of 4 terminal antennomeres; terminal antennomeres much larger than its preceding 3 antennomeres, with apical margin strongly obliquely truncate (Fig. 2 d). Mandibles bifid apically, with well-developed molar tooth (Fig. 2 c). Terminal maxillary palpomere at least weakly expanded apically (Fig. 2 e). Mentum (Fig. 2 f) subtrapezoidal, broadest anteriorly and medially shallowly rounded. Labial palps with three palpomeres, terminal labial palpomere subcylindrical, shorter than penultimate one (Fig. 2 f). Prosternal process 0.9 times width of coxal cavity; prosternal carinae incomplete anteriorly; surface between carinae punctate and setose (Fig. 2 b). Elytral epipleuron narrow, incomplete apically, not foveate (Fig. 3 a and d). Pronotal disc evenly convex. Prosternum moderately long in front of coxae, arcuate (Fig. 2 b); prosternal process broad, usually with complete carinae, rarely without carinae. Anterior margin of mesoventrite straight medially. Mesoventrite slightly narrower than coxal diameter with metaventrite always projected forward and arcuate; metaventral postcoxal lines strongly recurved. Tibial spurs absent (Fig. 2 g-i).

Male genitalia: Penis slender, extremely long (Fig. 3 j). Penis capsule highly sclerotised, inner arm bifurcate, abruptly recurved (Fig. 3 k). Penis guide with short asymmetrical apical tooth in inner view (Fig. 3 h); in lateral view, penis guide widest at base, then tapering gradually to a blunt apex and bearing a horned projection at the proximal end (Fig. 3 i). Parameres stout, distinctly longer than penis guide in lateral view, widened and apically rounded, densely setose apically (Fig. 3 i). Tegminal strut slender, distinctly longer than combined length of phallobase and penis guide (Fig. 3 h and i).

Female: Externally identical to male, but head black and elytra black with the apex more or less finely yellowish (Fig. 3 d-f). Prothorax black with lateral and anterior margins brown (Fig. 3 d-f).

Four instar larva (Figs 4, 5). Length 2.27 mm; width 1.28 mm. Body elongate oval, with short bristles and waxy, light yellow, with black stripes (Fig. 4 a-c). Head: light yellow, nearly semi-round (Fig. 5 a). Epicranial suture with frontal arms indistinct (Fig. 5 a). Three hemispherical stemmata dark, arranged in triangle, near the base of antennae. Antennae composed of only one antennomere with a long bristle and apical papillae (Fig. 5 b). Labrum squarish, with sparse bristles (Fig. 5 c). Mandible sclerotised with one apical tooth and a long bristle above the condyle, without basal tooth (Fig. 5 d). Maxillary palp with three palpomeres and apex with sensillae (Fig. 5 h). Labium with spare and thin bristles, labium palp with two palpomeres and small stout sensillae at apex (Fig. 5 g, i). Thorax: pronotum light yellow, has spare bristles with black stripes on two sides and two semi-round dorsal plates. Meso- and metanotum light yellow, with black stripes on two sides (Fig. 4 a-c). Legs light yellow, short, with sparse pale yellow hairs; tarsal claw without basal tooth and with a long lateral bristle on the external face of the tooth and spare bristles on the internal face of the tibiae (Fig. 5 e). Abdomen: nine segments, light yellow with spare tortuous bristles (Fig. 4 a-c).

Pupa (Fig. 4 d-e). Length 1.93 mm; width 1.25 mm. Body oval, yellow, with black stripes and bristles. Thorax: pronotum and metanotum yellow, trailing edge black; mesonotum yellow, with black stripes on two sides; metanotum yellow, nearly triangular. Abdomen: seven segments visible.

Diagnosis

This species is similar to most members of the genus Diomus in general habitus and colour pattern, but can be distinguished from those species by the extremely long penis and the robust penis capsule with a bifurcate inner arm.

Distribution

Guinea (Conakry), China (Guangdong) new record.