Pterotiltus impennis
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 impennis

description: 1. Pterotiltus impennis (Karsch, 1891) (type species of genus)
Figs 2–7; Table 1
Pygostolus impennis Karsch, 1891: 192. (Preoccupied, not Pygostolus of Haliday, 1833 (Hymenoptera)).
Pterotiltus impennis Karsch, 1893: 108, synonym (nom. nov. for Pygostolus impennis).
Pterotiltus impennis var. multicolor Bolívar, 1905: 228. Syn. Kirby 1910: 386.
Pterotiltus impennis var. multicolor – Ramme 1929: 313. — Johnston 1956: 259.
Pterotiltus impennis – Sjöstedt 1910: 8. — Dirsh 1965: 235. — Johnston 1956: 258; 1968: 173. — Hollis 1975: 226, fig. 64 (p. 227) (epiphallus). — Rowell 2005: figs 2–4 (male and female internal genitalia).
Type material
Lectotype (designated here)
CAMEROON • ♂; Barombi Station; [4°40′0″ N, 9°24′0″ E]; [1889 approx.]; S. Preuss leg.; MfN, DORSA BA000506S01.
Paralectotypes
CAMEROON • 1 ♂; same data as for lectotype; MfN, DORSA BA000506S02 • 3 ♀♀; same data as for lectotype; MfN, DORSA BA000506S03 to DORSA BA000506S05. (DORSA BA000506S05 is illustrated in Fig. 4A–C.)
Other material examined
CAMEROON • 2♂♂; Mukonye, near Kumba; [4°34′39″ N, 9°30′24″E]; 15–18 Feb.1938; S.G. Eisentraut leg.; MfN • 2 ♂♂; same data as for preceding; 23–25 Feb. 1938; S.G. Eisentraut leg.; MfN • 1 ♂; Barombi Crater; [4°40′0″ N, 9°24′0″ E]; 1 Oct. 1971; C.H.F. Rowell leg.; RC 71015 • 1 ♀; same data as for preceding; 30 Sep. 1971; RC 71006 • 2 ♀♀; Dja faunal reserve; [3°0′ N, 13°0′ E]; 23 Jul. 1976; T.E. Rowell leg.; in swamp; RC 76009, 76010 • 3 ♂♂; Kumba; [4°38′0″ N, 9°27′0″ E]; 2015 [no other data]; A. Simeunotchom leg.; ONC 1172017, 1152017, 1182017 • 2 ♀♀; same data as for preceding; ONC 1142017, 1122017 • 3 ♂♂; Tombel; [4°44′47″ N, 9°40′13″ E]; 2015 [no other data]; A. Simeunotchom leg.; ONC 292017, 272017, 282017 • 1 ♀; same data as for preceding; ONC 262017 • 2 ♂♂; Haut Nyong Division, Lobéké National Park; [2°16.667 N, 15°38.775 E]; 8 Dec. 2023; C. Oumarou-Ngoute leg.; ONC 7492023 D, 7502023D • 1 ♀; same data as for preceding; ONC 7482023 D.
NIGERIA • 1 ♂; Osomba (Akampka LGA); 1 Jun. 1986; J. Reid leg.; NHMUK • 1 ♂; same data as for preceding; 11 Jan. 1986; NHMUK • 10 ♀♀, 7 ♂♂; Bacoco, nr Calabar; 26 Oct. 1984; J. Reid leg.; NHMUK • 1 ♂; Calabar-Ekong Road, 80 km NE of Calabar; 3 May 1982; J. Reid leg.; NHMUK.
Description (Figs 3–5)
Male
Medium-sized (for measurements see Table 1 below, p. 16). Integument mostly smooth and shiny, but densely punctate on head and face, pronotum, and on thoracic and proximal abdominal tergites.
HEAD. Antennae filiform, longer than head and pronotum together, mostly black, but blue-black proximally and at extreme tip. Frons, mouthparts and genae white, with small blue-green markings on clypeus and labrum. Vertex and occiput blue-green, with a black triangular marking medially, the apex narrowing towards the interocular space. Eyes shiny black in life (drying to dull brown). Postocular stripe black, continuing backwards on to the upper part of the pronotal lobes.
THORAX. Pronotum predominantly black, but with the lower half of the lateral lobes white (continuing the line of the genae); disc of pronotum black with two large blue-green medial patches, one situated between the anterior margin and the second sulcus, and the other between sulci 3 and 4; metazona blue green. Fore and middle legs leaf green, all femora yellow-green, tarsi blue green. Hind coxae green, hind femora yellow green, darkening towards the knee, with a conspicuous dark green chevron pattern on both inner and outer faces. Hind knees and proximal part of hind tibiae, red; distal hind tibiae and tarsi light blue green: the hind tibiae are somewhat expanded laterally towards their tips. Tibial spines (7 external, 9 internal) and spurs brownish black. Tegmina greatly reduced to almost imperceptible scales on the mesothoracic tergites, black or colourless. Wings absent.
ABDOMEN. Abdominal tergites 1–3 coloured similarly to pronotum, i.e., tergites black with a medial green or blue-green marking. Tympanum open, white. Abdominal tergite 4 is yellow, tergites 5 & 6 light reddish brown, tergite 7 to tip of subgenital plate bright red. Male cerci blue green, slightly inwardly curved, the dorsal edge straight, the lower edge curving upwards to form a point apically. The points of the furcula of the male 10 th abdominal tergite are fused into a short vertical medial process, minutely bifid at the tip. This feature so far seems to be invariant between individuals, and allows instant specific recognition of the male.
PHALLIC COMPLEX. The phallus was described by Rowell (2005). The epiphallus (Fig. 6B–D) is distinctive within the genus, with a strong bridge and well-developed internal peaks on the lophal ridge (the “inner lophi” of Hollis 1975). The large ‘outer’ lophi are typical of the genus, being blade-like, more or less vertical, but strongly curved forwards (cephalad) towards their tips. The ventrolateral sclerite is robust (Figs 6–7) but its ventral flange is small and weakly bilobed (Fig. 7A, C) The valvular plate is small and less prominent than in other species of the genus; it is tectiform, short, with two rearward pointing projections and a transverse medial ridge on dorsal surface, with only limited lateral extensions (Fig. 7B). There are endophallic processes at the ventral end of the flexure abutting the ventral aedeagal sclerites (Fig.1). The tips of the processes are visually clear in stained preparations, but seem to be firmly fixed to the sclerites – perhaps even fused? Note that in impennis the bridge of epiphallus has two weakly sclerotized bumps laterally – see Fig. 6B–C.
Female
In most respects similar to male, though larger, but red tip of abdomen less strikingly and more diffusely coloured. Ovipositor and internal reproductive structures as in generic description (Fig. 2)
Measurements
See Table 1.
Designation of lectotype
From the 5 original syntypes we designate as male lectotype the specimen shown in Fig. 3A–C, with number DORSA BA000506 S01.
Distribution
Recorded from West and Central Cameroon and Eastern Nigeria (Cross River State).
Ecology
Many but not all records are from swamp forest. Several of the NHMUK Nigerian specimens are labelled as being found on ferns and there is one record of it eating an unidentified species of fern in captivity. This is perhaps the commonest species of the genus, it is certainly the most frequently collected and currently the best represented in museum collections.
Status of taxonomic material
Good. Both sexes known, plentiful museum material, modern localities identified.
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 10-16, DOI: 10.5852/ejt.2025.986.2853, http://zenodo.org/record/15235428