Pterotiltus occipitalis Ramme 1929
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 occipitalis

description: 11. Pterotiltus occipitalis Ramme, 1929
Figs 29–31; Table 9
Pterotiltus occipitalis Ramme, 1929: 317.
Pterotiltus occipitalis – Chopard 1945: 177. — Johnston 1956: 260. — Dirsh 1965: 236. — Hollis 1975: 228. — Mestre & Chiffaud 2009: 105. — Rowell & Hemp 2017: 86.
Type material
Holotype
CAMEROON • ♀; Yaoundé; [3.8480° N, 11.5021° E]; Jun.–Jul. 1897; S.G. von Carnap leg.; MfN, DORSA BA000032S01 (Fig. 29A).
Paratypes
DEMOCRATIC REPUBLIC OF THE CONGO • 1 ♀; Yambata; [2°26′0″ N, 21°58′0″ E]; Feb.–Mar. 1914; De Giorgi leg.; RMCA • 1 ♀; Beni; [0°30′ N, 29°28′ E]; Lt Borgerhoff leg.; RMCA • 1 ♂; Region du Bas-Uéle; 7–18 Nov. 1925; S.A.R. Prince Leopold leg.; RMCA 1827N (Fig. 30A).
Other material examined
CAMEROON • 1 ♂; Yaoundé, Nkolobisson; [3°87′ N, 11°52′ E]; 14 Jul. 1975; N.D. Jago leg; det. N.D. Jago 1975; NHMUK • 1 ♂; East Province, Haut Nyong Division, Lobéké Nat. Park; [2°15′0″ N, 15°45′0″ E]; 3 Dec. 2023; C. Oumarou-Ngoute leg; RC 7472023D • 2 ♀♀; same data as for preceding; RC 7462023D, 7432023D.
UGANDA • 2 ♂♂; Bundibugyo District, Semuliki National Park (Bwamba Forest), Sempaya-Ntandi trail; 770 m a.s.l.; [00°49′30″ N, 30°03′40″ E]; 17–18 Aug. 2006; C.H.F. Rowell leg.; RC 2006199 to 2006200 (Fig. 30C) • 3 ♂♂; same data as for preceding; MUMZ 2006198, 2006200, 2006201 • 1 ♀; same data as for preceding; RC 2006217 (Fig. 29C) • 1 ♂; Bundibugyo District, Semuliki National Park (Bwamba Forest), Bumaga-Ntandi trail; 700 m a.s.l.; [00°49′31″ N, 30°03′40″ E]; 22 Aug. 2006; C.H.F. Rowell leg.; RC 2006270 • 1 ♀; same data as for preceding; RC 2006271.
Description
Ramme’s (1929) description is accurate but applies only to his discoloured museum specimens (Fig. 31A). In life the colouration is slightly different. We give here his original description (in translation), but amended to describe the colouration of the live animal, and with added comments in parentheses ().
[Fastigium slightly depressed between the eyes; the anterior part of the fastigium wrinkled, with a well-defined median groove (especially visible in males). Frontal ridge sulcate above the medial ocellus, but obsolete below the ocellus. The cuticle between the second and third pronotal sulci only slightly inflated laterally (less so than in most other species of the genus). Pronotal disc and the tergites of the metathorax and first abdominal segment roughly wrinkled, not at all shiny]. (Furcula of male well developed in some individuals, in others reduced to a slightly bifid medial process (Fig. 30D–E), similar to the situation seen in P. coeruleocephalus (p. 36, Fig, 24)). [The morphology otherwise corresponds to that of genus diagnosis].
PHALLIC COMPLEX (Fig. 31A). Typical of the genus, but the oval sclerites of the epiphallus are elongate and strap-shaped and the outer lophi are wider and more bluntly pointed than in other species (Fig. 31C). The valvular plate is quite small, and terminates posteriorly in paired short dorsal processes (Fig. 31B).
Colouration
[(Eyes shiny black, drying to brown). Fastigium, vertex and occiput black with a greenish tinge, the dark colour extending ventrally over the gena behind the eye as far as the bottom of the eye. (There is no discrete postocular stripe). Frons and ventral half of genae a shining white (yellowish in dried material), clypeus and labrum green or blue green. (Palps green). Antennae black, with white tips (drying to yellow). Thorax and proximal abdomen a uniform light brown, without other markings; base of abdomen with a slight olive tinge, (distal segments of abdomen leaf green). Hind femur green, knee light brown, hind tibia green, darkening distally, with light brown condyle. Tarsi light brown marked with green]. A very distinctive colouration: the live animal is a uniform light tobacco brown, with green legs and abdomen and a strikingly black and white head.
Measurements
See Table 9.
Distribution
Previously recorded from Yaoundé (Cameroon) (Ramme 1929; Jago 1975 (specimen label in NHMUK, not published)) and Mt Cameroon (Chopard 1945); Yambata, Beni (both Ramme 1929), Bas Uélé (Dirsh 1970) (all DR Congo); and Semuliki (W Uganda) (Rowell & Hemp 2017). We have recently captured both sexes in the Lobéké National Park in far eastern Cameroon, near the CAR and DRC frontiers. Presumably occurs in suitable localities along the entire north bank of the Congo River from Cameroon to Uganda, the widest known range in this genus. To date there are no south bank records.
Ecology
In the Semuliki Valley of W Uganda P. occipitalis occurs syntopically with P. hollisi on Marantachloa leucantha (K.Schum.) Milne-Redh. and Pollia sp. in light gaps created by forest elephants in wet forest dominated by ironwood (Cynometra alexandri) (Rowell & Hemp 2017). Usually, a single light gap harbours only one species of Pterotiltus, but there are some that contain both. Individuals of occipitalis tend to be grouped together on the foodplant.
Status of taxonomic material
Adequate, both sexes are known, and modern localities.
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 51-56, DOI: 10.5852/ejt.2025.986.2853, http://zenodo.org/record/15235428