Melitonoma juvenca
Creators: name: Bezděk, Jan
Publisher: name: Zenodo
Year: 2025
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Coleoptera
Chrysomelidae
Melitonoma
Melitonoma juvenca

description: Melitonoma juvenca (Lacordaire, 1848)
Figs 1–3
Clythra (Melitonoma) juvenca Lacordaire, 1848: 379. Type locality: “Du Sénégal et de la côte de Guinée ”.
Melitonoma inclusa Jacoby, 1895: 170, syn. nov. Type locality: “ Togo (Bismarckburg)” [from the title, near todays Konkoa, Togo].
Melitonoma juvenca – Medvedev 1973: 188 (faunistics); 2000: 348 (comments, key); 2008a: 149 (key). — Medvedev & Beenen 2005: 361 (faunistics).
Differential diagnosis
In habitus, Melitonoma juvenca is most similar to M. dalaba sp. nov. The pronotum of M. juvenca is covered with distinct and well visible punctation, which is similar to that of M. dalaba sp. nov. Male protarsomeres I of both species are elongate, but in M.juvenca protarsomere I is shorter, 1.75 times as long as wide, while in M. dalaba sp. nov. it is longer, 2.45 times as long as wide (Figs 2N, 9O). The two species also differ in the shape of the penis, which is subhexagonal without an apical process in M. juvenca, but with a distinct triangular apical process in M. dalaba sp. nov. (Figs 3A–F, 9F–K). In M. simoni, the pronotum is completely or almost completely smooth, male protarsomere I (Fig. 5E) is slightly shorter, 2.20 times as long as wide, and the penis is elongated and narrow with a triangular apical third (Fig. 6A–F). In M. vinculata, the pronotum is covered with very fine punctation, visible under higher magnification, male protarsomere I (Fig. 7N) is very short, 1.10 times as long as wide, and the apical part of the penis is rounded laterally, with the tip widely triangular (Fig. 8A–F). Most specimens of M. juvenca have an orange base colour, while specimens of M. simoni and M. vinculata have a yellow or yellowish-brown base colour.
Females of M. juvenca, M. simoni and M. vinculata differ, in addition to the punctation of the pronotum, by the shape of the spermatheca, which is question mark-shaped in M. juvenca and M. simoni, while it is more C-shaped in M. vinculata. In M. juvenca the spermathecal duct is very thin without any coils, ca as long as the spermatheca. In M. simoni it is ca 2.5 times as long as spermatheca and forms many small coils. In M. vinculata it forms a large tangled-up ball (Figs 3I, 6I, 8I). The middle dorsal rectal sclerite is missing in M. juvenca (observed in three females), while it is present in M. simoni and M. vinculata (Figs 3J, 6J, 8K).
Type material
Other material examined
BENIN • 2 ♂♂, 1 ♀; 105 km N of Parakou, Bembereke (Borgou); 2 Jul. 2001; F. and L. Kantner leg.; NMPC • 1 ♂; 55 km NNE of Parakou, Son Tou (Borgou); 4 Jul. 2001; F. and L. Kantner leg.; NMPC.
GHANA • 2 ♀♀; Cape coast; 8 Jun. 1982; C.I.E. leg.; on maize; NHMUK.
REPUBLIC OF GUINEA • 1 ♀; Guinea; Chevrolat Coll.; NHMUK • 1 ♂ (Fig. 1C–D), original specimen of Clythra juvenca var. A; “ Guinea West”; MFNB.
SENEGAL • 1 ♀; Senegal; MFNB.
TOGO • 1 ♂; Bismarckburg; 20–27 Oct. 1893; L. Conradt leg.; MFNB • 1 ♀; Bismarckburg; 8 Aug.–24 Sep. 1892; L. Conradt leg.; MFNB • 1 ♀; “zw. Klein-Popo und Bismarckburg” [between Anecho and Bismarckburg]; 8–24 Aug. 1892; L. Conradt leg.; MFNB • 6 ♂♂, 12 ♀♀; Fazao-Malfakassa NP, Mare aux crocodiles campsite; 8°44′58.8″ N, 0°48′51.8″ E; 26Aug.–8 Sep. 2018; M.Aristophanous, M. Geiser, P. Moretto and B. Sanbena leg.; Sudanian savannah/gallery forest; NHMUK • 2 ♂♂, 1 ♀; same data as for preceding; JBCB • 3 ♂♂, 4 ♀♀; Fazao-Malfakassa NP, Point de vue campsite; 8°48′50″ N, 0°49′3.2″ E; 16–24 Aug. 2018; M. Aristophanous, M. Geiser, P. Moretto and B. Sanbena leg.; Sudanian savannah; NHMUK • 1 ♂; Fazao-Malfakassa NP, East of Bounako ranger station; 9°10′14.1″ N, 0°57′33.4″ E; 25–26 Aug. 2018; M. Aristophanous, M. Geiser, P. Moretto and B. Sanbena leg.; Sudanian savannah; NHMUK.
Description
Male (Fig. 2A)
APPEARANCE AND COLORATION. Body length: 6.0– 6.9 mm. Body elongate, subparallel, convex. Head black. Pronotum usually with large black spot touching posterior margin, spot deeply incised in middle of anterior margin, lateral and anterior pronotal margins yellowish brown to orange; rarely black spot enlarged, touching also anterior pronotal margin or black pattern reduced to three spots (two larger irregular spots laterally and one small elongate spot in middle) (Fig. 2E–H). Scutellum black. Elytra yellowish brown to orange with five black spots (1, 2, 2) and black apex of elytra; pairs of spots usually connected forming one or two transverse bands, rarely both bands connected, or humeral spot connected with middle exterior spot, or middle exterior spot missing (Fig. 2I–M). Ventral side of body black, except pronotal hypomeron yellowish brown to orange. Antennomeres I–III orange (I sometimes darkened), IV–VI black with orange bases, VII–XI black. Legs black, in very old specimens can be dark reddish brown.
HEAD (Fig. 2C). Mandibles moderately enlarged, basal parts slightly swollen, apical parts flat, even and glabrous, lateral sides covered with long pale setae; left mandible somewhat larger, with lateral margin straight and oblique, and apex hook-like, lateral side with distinct groove. Labrum transverse with rounded anterior angles and shallowly emarginated anterior margin, surface smooth and glabrous except small punctures along margins bearing pale setae. Anterior margin of clypeus widely-shallowly emarginated. Anterior part of head slightly convex and uneven, covered with small punctures and along anterior margin of clypeus also with short setae. Eyes moderately large. Frons wide, 2.50–2.70 times as wide as diameter of eye, surface uneven, almost glabrous, except setae cumulated along internal margins of eyes. Frons separated from vertex by shallowly impressed rounded line. Vertex convex, glabrous, lustrous, covered with indistinct punctures. Antennae short, 0.17 times as long as body, antennomere I club-shaped, III very small, antennae shortly serrated from antennomere IV.
PRONOTUM. Convex, transverse, 1.65–1.75 times as wide as long, widest before base. Surface lustrous, covered with small fine punctures (Fig. 2D), punctation disappearing along anterior and lateral margins, punctures bear microscopic setae visible only in high magnification. Anterior margin straight to slightly concave, lateral margins moderately rounded, posterior margin slightly rounded and moderately expanded in scutellar area. Anterior margin thinly bordered only in lateral parts, middle part unbordered, lateral margins widely bordered and posterior margin thinly bordered. Anterior angles obtusangulate, posterior angles rounded, all angles with setigerous pore bearing long seta. Posterior angles slightly elevated above elytral base. Scutellum subtriangular, with rounded tip, glabrous, impunctate, along basal margin impressed and punctate.
ELYTRA. Subparallel, 1.45–1.50 times as long as wide (measured in middle) and 0.50 times as long as body. Surface glabrous, subopaque, densely covered with very fine, confused punctures and fine microsculpture. Humeral calli developed. Basal margin forming sharp keel. In lateral view, lateral margin of each elytron sinuate. Epipleura lustrous, glabrous, slightly concave, very wide at base, gradually narrowed posteriorly, disappearing in ⅔ of elytral length. Macropterous.
VENTRAL SIDE OF BODY. Densely covered with short setae. Abdomen more or less concave in lateral view. Pygidium moderately convex.
LEGS. Protibiae and protarsi moderately enlarged. Protarsomere I (Fig. 2N) elongate, 1.75 times as long as wide, as wide as II, lateral sides slightly rounded, protarsomere II 1.32 times as long as wide, parallel in apical half, convergent in basal half, length ratio of protarsomeres I–III and V equals 100-71-68- 67 (100 = 0.70 mm). Mesotarsomere I elongate, parallel, with narrowed base, as wide as II, length ratio of mesotarsomeres I–III and V equals 100-60-60-80 (100 = 0.50 mm). Metatarsomere I elongate, subparallel, with narrowed base, as wide as II, length ratio of metatarsomeres I–III and V equals 100- 60-60-80 (100 = 0.5 mm). Claws simple.
PENIS (Fig. 3A–F). Widest in apical quarter, apical part subhexagonal, tip rounded, apical margins wide and flat. In lateral view, dorsal margin slightly sinuate, ventral margin bent at middle in form of right angle, apex sharp. In ventral view, penis with long keel, wider and convex in apical part, sharp and narrow in median part, distinctly concave laterally from keel, anteroapically with small elevation on each side. Line of short setae visible along lateral margin in ventral view. Ventral surface and most of dorsal surface covered with punctures and wrinkles. Internal sac (Fig. 3G–H) with three pairs of small hook-like sclerites and one long needle-like sclerite, 0.77 times as long as width of penis in widest place.
Female (Fig. 2B)
Body length: 6.2–7.7 mm. Head, mandibles, tarsi and protibiae not enlarged. Abdomen convex in lateral view, last abdominal ventrite with medial hollow. Apex of pygidium slightly emarginated. Spermatheca question mark-like, with gradually narrowing and sinuate apical part, spermathecal duct very thin, without any coils, ca as long as spermatheca (Fig. 3I). Dorsal rectal sclerites small, longitudinally suboval, with slightly irregular margins, without middle dorsal sclerite (Fig. 3J). Ventral rectal sclerites transverse, slightly oblique, anterior margin emarginated near base, distal part fan-shaped and distinctly wider than proximal part (Fig. 3K). Tergite VIII and ovipositor as in Fig. 3L.
Distribution
Benin (present paper), Ghana (Medvedev 1973; present paper), Republic of Guinea (Lacordaire 1848; present paper), Senegal (Lacordaire 1848; present paper) and Togo (present paper). Based on the examination of the voucher specimen, the record of M. juvenca from Niger (Medvedev & Beenen 2005) refers to M. puncticollis Lefèvre, 1883.
Remarks
Jacoby & Clavareau (1906) listed Melitonoma inclusa as a synonym of M. simoni. Two female syntypes of M. inclusa deposited in NHMUK were examined. In one syntype, the head and pronotum are missing. The pronotum of the second syntype is covered by fine, dense punctures, which allows me to propose M. inclusa as a new synonym of M. juvenca.
Two taxa, Melitonoma puncticollis Lefèvre, 1883, and M. terminata Jacoby, 1903, are resurrected from the synonymy with M. juvenca. Clavareau (1913) listed M. terminata as a synonym of M. puncticollis and Medvedev (1971) synonymised M. puncticollis with M. juvenca without any comments. The type specimens of both taxa were examined. They do not belong the M. juvenca species group; moreover, they represent two different species. However, their identities will be resolved later in a subsequent paper on Melitonoma.
In the original description, Lacordaire (1848) explicitly mentioned the male from Klug’s collection and the female from Dejean’s collection. The collection of Johann Christoph Friedrich Klug is deposited now in MFNB. In the historical accession book, two specimens (males) of Melitonoma juvenca are entered under the number 23269. One of the males with one large irregular black spot on the pronotum and a black posterior transverse band on the elytra agrees well with the description and is designated here as a lectotype. The second male, with a black pronotal pattern fragmented into three spots and an interrupted posterior transverse band on the elytra, agrees with variety A in Lacordaire (1848). This male was expressly excluded from the type series as a distinct variant marked by a letter (Art. 72.4.1, ICZN 1999).
The female from Dejean’s collection was not examined. The Clytrini from Dejean’s collection were probably bought by Marquis de Brème within “cryptocephalides” (Mannerheim 1842) and are deposited in the Museo Regionale di Scienze Naturali di Torino.
description: Published as part of Bezděk, Jan, 2025, Revision of the genus Melitonoma (Coleoptera, Chrysomelidae). 1. History, type species and revision of the M. juvenca species group, pp. 208-237 in European Journal of Taxonomy 976 on pages 211-217, DOI: 10.5852/ejt.2025.976.2791, http://zenodo.org/record/14901634