Cyclidinus Westwood, 1874

Rodrigues, Diego F., Grossi, Paschoal C. & Vaz-de-Mello, Fernando Z., 2025, Taxonomic revision of Cremastocheilini (Coleoptera: Scarabaeidae: Cetoniinae) from South America and an updated key for the genera of the New World, Journal of Natural History 59 (17 - 20), pp. 1063-1125 : 1072-1074

Genus Cyclidinus Westwood, 1874

( Figures 1 (D), 4, 5, 6, 31(B, C, E))

Type species

Cyclidinus lugubris Westwood, 1874 , by subsequent designation here.

Taxonomic history

Cyclidinus Westwood, 1874, p. 55 –56 (original description). – Schenkling 1921: 375 (catalogue). – Basilewsky 1956: 52 (catalogue). – Krikken 1976: 314 (key to the genera of Cremastocheilini ). – Krikken 1981: 416 (taxonomic review). – Krikken 1984: 45 (catalogue of genera). – Krajčik 1999: 42 (catalogue). – Carvajal et al. 2011: 297 (catalogue). – Di Iorio 2013: 87 (distribution and references). – Rodrigues et al. 2023 (catalogue). – Schoolmeesters, 2024 (catalogue).

Diagnosis

Cyclidinus is recognised by the following combination of characters: clypeal projection bent upwards in frontal view; pronotum hexagonal ( Figures 1 (D), 4 (C)–5(C)); apical-lateral tooth of protibia as long as the apical spur, wide in lateral view ( Figures 4 (D)–5(D)).

Redescription

Size: length: 13.8–12.0 mm; width: 7.4– 6.5 mm. Body: Elongate, dorsally flattened, completely or partially velutinous. Colour: Body dorsally mustard yellow, black, or black with mustard yellow macules ( Figures 4 (A), 5(A)); ventrally black, dark reddish brown, or one of these colours covered with a mustard yellow velutinous coating ( Figures 4 (B), 5(B)); mentum, palps and antennomeres black, dark-brownish, or light-brownish. Eyes black, brown, or yellow; if not black, may have black spots. Hind wing yellow-amber with metallic reflection. Head: Clypeal projection bent upwards in frontal view; clypeolateral declivity rounded at the corners. Frons ocellate-punctate and/or rugose; antegenal protusion evident, eye-canthus superficially rugose and often velutinous; scape semitriangular, superficially rugose, with occasional setae on the sides. Mentum with posterior margin broadly ‘V’-shaped, rounded at the other corners. Pronotum: Disc hexagonal with obtuse angles, rounded on the sides ( Figures 1 (D), 4(C), 5(C)); surface irregularly ocellate-punctate, often velutinous. Scutellum: Triangular, surface ocellate-punctate, often velutinous. Elytra: Disc elongate, with a slightly transverse margin anterioly and rounded posteriorly ( Figures 4 (A), 5(A)); with one humeral and anteapical umbone on each elytron; surface heavily oval-ocellate-punctate, often velutinous. Thoracic venter: Hypomerum: Shallowly concave below procoxa; surface rugose or striate convergently. Prosternum : Narrow anteriorly, forming a pointed projection, setose at the anterior base and on the tip. Mesoventrite: Acute angle between middle legs; rugose or differently punctate, with occasional setae. Mesepisternum: Rugose and punctate. Mesepimeron: Rugose, with occasional setae; barely visible dorsally. Metaventrite: With a very evident median sulcus, punctate and ‘c’-punctate or ocellate-punctate, velutinous, and with occasional setae. Metepisternum and metepimeron ‘c’-puntate or ocellate-punctate, velutinous, with short setae on the lateral sides of the elytra. Legs: Tarsus: Last tarsomere (V) longer than others. Protibia: Ventral and dorsal surfaces rugose, differently punctate and/or convergently striate; sparsely setose occasionally; one apical spur and three teeth: apical-lateral, apical-ventral, and lateral-proximal; apical-lateral tooth as long as the apical spur ( Figures 4 (D), 5(A)), wide when viewed laterally. Profemur: Rugose ventrally and striate dorsally, with setae medially. Mesotibia shorter than Metatibia ( Figures 4 (B), 5(B)), both dorsally flattened and rugose; ventral surface with connecting striations, forming cells, some of which bear setae in the middle; with two pairs of apical teeth and one proximal tooth, presenting a superficially rough concavity between the proximal and apical teeth; two apical spurs. Metafemur wider than mesofemur, both with ventral surface striated, that connect, forming cells, or ocellate-punctate, in both cases with setae emanating from the central edge. Procoxa and mesocoxa rugose and/or striatiate, with connecting cells or punctures, occasionally with setae; the same for trochanter. Metacoxa: Ocellate-punctate, occasionally velutinous. Abdomen: Ventrites ‘C’-shaped punctate or ocellate- punctate with setae, glossy and/or velutinous; penultimate ventrite with a slight concavity; spiracle of the last tergite elevated, always visible. Pygidium: Convex, ocellate-punctate, variably velutinous.

Geographical distribution

Cycidinus is known from Amazon Forest in Brazil, Colombia, French Guiana, and Peru ( Figure 6 ).

Key to the species of Cyclidinus Westwood

1. Body predominantly covered by mustard yellow velutinous coating ( Figure 4 (A–C, E– F)). Mentum thickened at posterior margin .... Cyclidinus lugubris Westwood 1874

1’. Body predominantly covered by black velutinous coating ( Figure 5 (A–C, E–F)). Mentum not thickened at posterior margin ...... Cyclidinus peruanus ( Moser, 1910)

Figures

Figure 1. Pronotum shapes of Cremastocheilini genera from the Americas. (A) Centrochilus Krikken, 1976. (B) Cremastocheilus Knoch, 1801. (C) Cyclidiellus Krikken,1976. (D) Cyclidinus Westwood,1874. (E) Cyclidius MacLeay, 1838. (F) Genuchinus Westwood, 1874. (G) Krikkenjanius Rodrigues, Grossi and Vazde-Mello gen. n. (H) Lissomelas Bates, 1889. (I) Paracyclidius Howden, 1971. (J) Psilocnemis Burmeister, 1842. (K) Quititinus Rodrigues, Grossi and Vaz-de-Mello gen. n.

Figure 4. Cyclidinus lugubris Westwood, 1874. Female at CEMT (Brazil, Amazonas, Manaus). (A) Habitus, dorsal view. (B) Habitus, ventral view. (C) Pronotum, dorsal view. (D) Protibia, dorsal view. (E) Habitus, dorsolateral view. (F) Habitus, lateral view. Scale bars = 1 mm.

Figure 5. Cyclidinus peruanus (Moser, 1910) comb. n. Lectotype of Genuchinus peruanus Moser, 1910. Female at MFNB (Peru, Junín, Chanchamayo, La Merced). (A) Habitus, dorsal view. (B) Habitus, ventral view. (C) Pronotum, dorsal view. (D) Protibia, dorsal view. (E) Habitus, dorsolateral view. (F) Habitus, lateral view. (G) Labels. Scale bars = 1 mm.

Figure 6. Geographical distribution map of Cyclidinus lugubris Westwood, 1874 and Cyclidinus peruanus (Moser, 1910).