Digentia fasciata Ramme 1929
Creators: name: Oumarou Ngoute, Charly
name: Rowell, C. H. F.
Publisher: name: Zenodo
Year: 2025
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Orthoptera
Acrididae
Digentia
Digentia fasciata

description: Digentia fasciata Ramme 1929
Figs 1, 5 C, 7 C, 8 D, 9 B, E, 10 B, G, 12 B, E, 13 C, 14 A, B, 15 A, I, Tables 2, 4
Type material. —
Holotype: CAMEROON • ♂; Lolodorf; L Conradt S leg.; DORSA BA 000033 S 01 C. Allotype: CAMEROON • ♀; Yaoundé; V Carnap S leg.; DORSA BA 000033 S 02; MfN. [not examined]
Examined material. —
7 (4 ♂ and 3 ♀): ♂, Mbalmayo, CAMEROON, 15 - I- 1974, specimen N ° 74012, T. E. Rowell leg., N. Jago ID., RC; ♂, Ngoyla, CAMEROON, IV- 2021, specimen N ° 2021012, C. Oumarou-Ngoute leg., ONC; ♂, Ngoyla, CAMEROON, IV- 2021, specimen N ° 2021013, C. Oumarou-Ngoute leg., ONC; ♂, Ngoyla, CAMEROON, IV- 2021, specimen N ° 2021015, C. Oumarou-Ngoute leg., ONC; ♀, Mbalmayo, CAMEROON, 15 - I- 1974, specimen N ° 74011, T. E. Rowell leg., RC; ♀, Ngoyla, CAMEROON, IV- 2021, specimen N ° 2021016, C. Oumarou-Ngoute leg., ONC; ♀, Ngoyla, CAMEROON, IV- 2021, specimen N ° 2021017, C. Oumarou-Ngoute leg., ONC; (Fig. 14). We were unfortunately unable to borrow the types from Berlin.
Redescription. —
The original description of Ramme 1929 of this species is very short; the English version is “ Fastigium somewhat longer than broad, rounded in front. Antennae 1.25 × the head and pronotum together, apically somewhat thickened. Anal segment with produced and raised edges. Supra-anal plate narrow, tongue-shaped, basally expanded, with shallow longitudinal medial groove. Cercus tapers to a long spike. Female also corresponds to this. ” We give here a more extended description.
Male. Body of medium size (average L = 17.98 mm; Table 2), integument shiny, rugose on head, pronotum, tergites of mesothorax and metathorax, and the first abdominal tergites.
Head. Antennae filiform, longer than head and pronotum together (average Ant / P = 2.14); fastigium of vertex short, about twice as wide as long, pentagonal, slightly oblique and rugose, frontal ridge well developed. Eyes oval, protuberant; interocular space (average IOS = 0.38 mm) slightly wider than antennae scape, with weak medial furrow.
Thorax. Pronotum cylindrical, lateral carinae absent, medial carinae weak; midline of the disc crossed by three deep transverse sulci, space between sulci 2 and 3 slightly wider than metazona; metazona short, about one-fourth of the length of prozona; posterior margin of metazona concave, notched in the midline. Anterior margin of pronotum rounded, very slightly notched in the midline (Fig. 5 C); prosternal process conical, pointed; mesosternal space about 2 times longer than wide, lobe rounded; metasternal space open, less than half the width of the mesosternal space. Tegmina extremely reduced, minute, narrow, and lobiform, reaching or slightly exceeding the posterior margin of mesothoracic segment (Fig. 7 C); hind femur slender; lower genicular lobe pointed; hind tibia slender, not expanded apically (Fig. 8 D). Seven to eight external tibial spines, external apical spine of the tibia present, nine to ten internal tibial spines (Table 2); internal spurs larger than external spurs.
Abdomen. Tympanum wide, rounded; the tip of abdomen curved upward; last abdominal tergite divided in the midline, furcula lobiform, with rounded and upwardly inflated margins or lobes either side of the midline. Supra-anal plate triangular in dorsal view, somewhat elongated distally with a rounded tip. Well-defined medial longitudinal groove proximal, bounded posteriorly by transverse ridge that extends across width of the plate; cercus flat, compressed laterally, inwardly curved, pointed with acute tip very slightly excised, reaching or slightly exceeding the tip of subgenital plate dorsally (Figs 9 B, E, 10 B, G); subgenital plate conical with rounded upwardly directed apex.
Phallic complex. Phallic complex (Fig. 15 A – C) of small size for the genus. Epiphallus small in the genus, bridge not divided, anterior margin slightly concave, notched in the middle, posterior margin almost straight; outer lophi conical, slender, upwardly curved with rounded tip; inner lophi almost rounded; anterior processes slender, incurved; oval sclerite elongated with rounded tips (Fig. 15 D – G). Cingular apodemes slender, elongated, with rounded apex, somewhat acute dorsally, rami rounded not fused ventrally; ventrolateral sclerite laterally flat, tapered toward the tips. Endophallus small and slender; valvular plate with three lobes, the middle lobe blunt; ventral aedeagal sclerite narrow, long with rounded apex; endophallus apodeme wide lobiform; gonopore process elongated with slightly wide and rounded apex (Fig. 15 H, I).
Female. In general, similar to the male. Female particularities: medium size (average L = 23.18 mm) (Table 2). Tip of abdomen not curved upward; last abdominal tergite without inflated margins or lobes; supra-anal plate triangular with rounded apex; cercus conical with acute apex, straight, reaching or slightly exceeding the tip of the supra-anal plate (Fig. 12 B, E); dorsal ovipositor valves straight, smooth, with rounded apex; ventral ovipositor valves wide basally with rounded corner or lobe, incurved in the middle and straight apically with rounded apex; egg guide straight, pointed, about 1 / 3 the length of ventral ovipositor valves (Fig. 13 C).
Sexual dimorphism. In D. fasciata, Ant male / Ant female is 0.76 and 0.94 after normalization (Table 2). The male antennae are slightly shorter than the female antennae (differs from D. rufogeniculata). Moreover, male interocular spaces are more narrow (0.82) than in female (Table 2). After normalization, the ratios of the other body dimensions are closely similar in both sexes (Table 2).
Coloration. The description given here differs somewhat from that of Ramme 1929, probably because we describe fresh materials, while Ramme described dried specimens from the Berlin Museum (MfN).
Male and female. (Fig. 14) Body multicolored, predominantly green-yellow (Ramme 1929 described as yellow-brown); fastigium of vertex olive-yellow; vertex olive-yellow with black or green-black longitudinal bands either side of the midline extending onto pronotum, mesothorax, metathorax, and up to the fifth abdominal segment, or reaching the last segment in some specimens. Eyes blackish in life, fading to brown when dried; frons and genae olive-yellow (dirty olive for Ramme), the olive-yellow band continues laterally forming two patches on the pronotal lobes (Fig. 6 B) and extending rearwards to the mesothoracic and the metathoracic pleura; distal part of clypeus and labrum olive-yellow, apical part brown; mandibles brown, and palps green-olive, scape and pedicel of antennae green, flagellum green-brown or black. Pronotal disc multicolored, predominantly olive-yellow with a medial black or green-black stripe, and two more lateral black stripes that extend dorsally onto the mesothoracic and metathoracic tergites; transverse sulci of the pronotum black; prothoracic, mesothoracic and metathoracic sterna red. Middle legs dirty olive, hind femur predominantly green, upper internal area and medial external area green, basal external area, basal internal area and medial internal area red distally but greenish proximally; upper genicular lobes black, basal lobe green-yellow; tibia green blue (Ramme described as olive-green), tibial spines green-yellow with black tips; tarsi green-yellow or olive. Abdominal tergites olive-yellow with a medial black or green-black band, and two more lateral bands reaching the last segment in some specimens; supra-anal plate and cercus olive-green, ovipositor valves olive-green; sub-genital plate and abdominal sterna red.
Distribution. —
CAMEROON: Lolodorf (4°7'51"N, 10°38'30"E), L. Conradt S leg.; Mbalmayo (4°38'3"N, 11°25'35"E) – (RC); Ngoyla (3°39'35"N, 13°56'11"E) – (ONC); Ongot (3°51'28"N, 11°23'59"E) – (ONC); Zamakoe (3°20'17"N, 11°19'8"E) – (ONC); Ngutadjap (2°42'N, 11°03'E) – (ONC). Ramme (1929) also refers to a female from the region of Ouesso, Congo Republic (1°36'38"N, 16°3'5"E) (Fig. 1).
Habitat. —
At Ngutadjap and Ngoyla, we found Digentia fasciata in the same habitat as Digentia viridissima sp. nov. We describe this habitat below (Table 4).
description: Published as part of Oumarou Ngoute, Charly & Rowell, C. H. F., 2025, Review of the African genus Digentia Stål, 1878 (Orthoptera, Acrididae, Oxyinae), pp. 11-30 in Journal of Orthoptera Research 34 (1) on pages 11-30, DOI: 10.3897/jor.34.126949