Pterotiltus inuncatus
Creators: name: Rowell, C. H. F.
name: Oumarou-Ngoute, Charly
Publisher: name: Zenodo
Year: 2025
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Orthoptera
Acrididae
Pterotiltus
Pterotiltus inuncatus

description: 2. Pterotiltus inuncatus (Karsch, 1892)
Figs 8–11; Table 2
Pygostolus inuncatus Karsch, 1892: 72 (syn. Karsch 1893). (Preoccupied, not Pygostolus of Haliday, 1833 (Hymenoptera)).
Pygostolus inuncatus – Karsch 1893: 108 synonym (nom. nov.) Pterotiltus.
Pterotiltus inuncatus – Kirby 1910:387. — Ramme 1929: 315. — Chopard 1945: 177 — Dirsh 1956: 276; 1961: 401, fig.24; 1965: 235. — Johnston 1956: 259; 1968: 173. — Hollis 1975: 226, fig. 67. — Mestre & Chiffaud 2006: 245.
non Pterotiltus inuncatus – Bolívar 1908: 106. (Misidentified – Bolívar named it Pterotiltus inuncatus var. nigroantennata. This specimen (RBINS, examined) is definitely not conspecific with inuncatus Karsch, 1892. We consider this to be a separate taxon: P. nigroantennatus Bolívar, 1908 stat. nov. See p. 33).
Type material
Lectotype (designated here)
CAMEROON • ♂; Buea; [4°10′0″ N, 9°14′0″ E]; 1–10 Apr. 1891; S. Preuss leg.; MfN, DORSA BA000804S01.
Paralectotypes
CAMEROON • 4 ♂♂; same data as for lectotype; MfN, DORSA BA000804S02 to DORSA BA000804S05 • 1 ♀; same data as for lectotype; MfN, DORSA BA000804S06.
Other material examined
CAMEROON • 1 ♂; Buea; [4°10′0″ N, 9°14′0″ E]; 20 May 1904; Glauning S. leg.; MfN, MDORSA 00003 • 1 ♂; Mt Cameroon, Musake; [4°10′15″ N, 9°18′50″ E]; 6350 feet [= 1935 m a.s.l.]; 9 Jan. 1932; M. Steele leg; MfN, also labelled BM 1934-240 (presumably originally from NHMUK collection) • 3 ♀♀; Mt Cameroon, Buea; [4°10′0″ N, 9°14′0″ E]; 900–1200 m a.s.l.; 10–17 Oct. 1910; E. Hintz leg.; MfN • 6 ♂♂; Mt Cameroon, Post and Telegraph Road; 4700 feet [= 1433 m a.s.l.]; Dec. 1960; N.D. Jago leg.; NHMUK • 2 ♂♂; Kumba; [4°38′0″ N, 9°27′0″ E]; 2015 [no other data]; A. Simeunoutchom leg.; ONC 1122017, 1102017 • 1 ♀; same data as for preceding; ONC 252017.
Description (of the original syntypes, belonging to the southern population; see Figs 8–9)
Small for the genus (see Table 2 for measurements).
HEAD. Vertex and occiput black, eyes now brown (but are black in life). Postocular stripe dark blue-black. Fastigium olive brown. Antennae, blackish brown, in life tinged greenish basallly; tips slightly flattened and light brown. Frons, frontal ridge, clypeus and lower genae cream (white in life). Labrum, outer face of mandibles, mottled blue-grey and black. Palps green.
THORAX. Pronotum mostly black. A medial patch of dirty white between anterior margin of pronotum and sulcus 2. Lighter colour on the anterior ventral angle of pronotum and part of the prothoracic episternum. Metazona very short, mostly cream/white, including posterior ventral angle. Mesothoracic tergite black with narrow red posterior margin. Pleura blue/grey and black, shading to cream near coxal aperture, flecked with red. Elytra vestigial, squamoid, not quite reaching posterior margin of mesothoracic segment, whitish. Metathoracic tergite solid red, integument somewhat pitted. Wing rudiment reduced to a cuticular ridge. Pleura blue-black dorsally, cream coloured ventrally. All legs were probably green (as in living specimens), but now yellowish. Hind knee red. Hind tibia red proximally by knee, then green distally. Hind tibia expanded laterally distally. Tibial spines and spurs greenish black.
ABDOMEN. Tergites 1–4 solid red, remaining segments green. Male has a small but distinct furcula, separation of points 0.3 mm (Fig. 10A).We have not seen individual variation in the furculae of this species.
PHALLIC COMPLEX. The phalli of specimens DORSA BA000804 S01 and DORSA BA000804 S05 were extracted and prepared. The male epiphallus shows the typical genus form, with a divided bridge and forwardly sloping blade-shaped lophi (Fig. 10B). It is more gracile than the epiphalli of other species – reflecting the small size of this species relative to most other Pterotiltus spp. The valvular plate is selliform and distinctive, with the posterior extremity formed into two diverging and downwardly directed lobes (Fig.10C). The ventral flange (Fig.10E) is well developed, doubling the width of the ventrolateral sclerite in the ventral midline.
Female (Fig. 9)
Similar to male but differs in colouration of metathoracic and abdominal tergites. These have only diffuse red markings, tending to black in the midline. The pronotal patterning is less distinct.
Polymorphism
This species occurs in two colour forms. Recent material from Kumba, Cameroon, and photographs from Mt Koupé, Cameroon, and from E Nigeria (Fig. 11A–D), are specimens which differ in colour pattern from the MfN specimens (Figs 8–9) and from the 1960s NHMUK specimens (all of which are from Buea area, or the southern slopes of Mt Cameroon). In the former (more Northern) specimens the terga of the metathorax and 1 st abdominal segments are coloured bright yellow, rather than red as in the (Southern) types (see Figs 7–8), and the head is almost completely black. There is a narrow band of blueish white on the lower frons, but it does not extend to the genae, which are black. The hind knees can be black or red, and this is not simply correlated with the colouration of the head and abdominal tergites. Both the southern (all-red abdominal tergites, white frons) and the Nigerian (red & yellow tergites, black frons) populations have red knees, while the northern Cameroonian specimens (Mt Koupé & Kumba, red & yellow tergites, black frons) have black ones. Within the southern form (Figs 8–9) both red and black knees can be found. However, the phallus is uniform in all localities.
Measurements
See Table 2.
Designation of lectotype
We designate as male lectotype the specimen shown in Fig. 8A–C, with number DORSA BA000804 S01. The lectotype and all the paralectotypes are in the MfN, Berlin. The phallus of the male lectotype has been dissected, and the preparation is mounted on the pin of the specimen.
Distribution
Recorded from southwestern Cameroon, and from the Oban Highlands of E Nigeria (Cross River State). In both countries it is found principally in highland areas (ca 1000 m a.s.l. and above). The type series, Hintz’s females, and the NHMUK sample all come from the southern slopes of Mt Cameroon; Kumba and Mt Koupé lie to the north and west of this area.
Status of taxonomic material
Good. Both sexes known, plentiful museum material, modern localities identified.The geographical variation in colouration and pattern still needs investigation.
description: Published as part of Rowell, C. H. F. & Oumarou-Ngoute, Charly, 2025, Review of Pterotiltus Karsch, 1893 (Orthoptera, Acrididae, Oxyinae), pp. 1-104 in European Journal of Taxonomy 986 on pages 16-22, DOI: 10.5852/ejt.2025.986.2853, http://zenodo.org/record/15235428