Pterotiltus rubroantennatus Ramme 1929, stat. nov.
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 rubroantennatus

description: 6. Pterotiltus rubroantennatus Ramme, 1929 stat. nov.
Fig. 16; Table 4
Pterotiltus apicalis rubroantennata Ramme, 1929: 315.
Pterotiltus apicalis rubroantennatus – Johnston 1956: 258. — Mestre & Chiffaud 2009: 105.
This taxon was first erected as a subspecies of P. apicalis by Ramme for mainland African specimens in the Berlin and other European museums. It agrees in some aspects with Bolívar’s description of P. apicalis, but has red (not brown) antennae and sometimes other additional red markings. All of Ramme’s original syntypes are conserved in MfN Berlin and have been examined for this review. We consider that Ramme’s type series includes three different species, corresponding to his holotype male, his paratype male, and his paratype females.
Type material
Holotype
CAMEROON • ♂; Cross River, Ossidinge Station; [5°53′15″ N, 9°7′39″ E]; 18–20 Oct. 1901; H. Glauning leg.; MfN, DORSA BA000507S01.
Redescription
The holotype is more than 120 years old – the original colouration is sometimes difficult to determine. See Fig. 16A–B.
HEAD. Fastigum and antennae red. Eyes brown, probably were black in life. Surface of fastigium finely pitted. Frons, clypeus, and upper portion of labrum: white. Lower portion of labrum: red. Palps – now yellow, probably were green in life. Genae and outer sides of mandibles, white. Postocular stripe: black. Vertex and inter-ocular space: integument coarsely pitted. These areas are a slightly weaker colour (black) than the postocular stripe – perhaps were originally blue-black? There are two patches of a lighter yellowish colour on the occiput (Fig. 16B), converging forwards towards the interocular space.
THORAX. Pronotum: ground colour black. The white band of the lower genae continues weakly on to lower part of pronotal lobes, forming a band fading out towards the rear. Disc of pronotum basically black, but with a large medial pale spot – originally blue-white? – anterior to sulcus 2, extending to anterior margin of the pronotum, and another between sulci 3 & 4. Posterior margin of the metazona green. Thoracic pleura grey blue: might have been blue-black originally? Meso- and metathoracic nota black, each with large medial white patch. Tegmina and wings absent.
LEGS. Pro and mesothoracic legs – coxa & trochanter – dirty green. Femora: yellow, possibly were originally green. Tibiae & tarsi: green. Hind leg – coxa & trochanter: probably were green. Femur – probably green, or possibly yellow. Knee red. Tibia – green, but condyle red. Tarsi – missing.
ABDOMEN. Abd. 1 tergite: anterior and posterior segmental margins are black, remaining area is a white or blue-white medial patch. Tympana large, circular and open. Abd. tergites 2–3, and 4-partim: black, with small medial patches of blueish white. Abd. tergites 4-partim, 5, 6-partim: yellow. Abd. tergite 6-partim to subgenital plate red, including the supra-anal plate. Cerci green. Posterior margin of Abd. tergite 10 has a furcula of two very small processes, separation 0.32 mm, with a very slight medial notch between them.
PHALLIC COMPLEX. Epiphallus – see Fig. 16C. Outer lophi tapering, curved, blade-like. Inner lophi absent. The outer lophi are wider in axial view than is commonly the case in this genus. To preserve the unique specimen, we did not further dissect the phallic complex, and so cannot describe the valvular plate, the ventral aedeagal sclerites or the ventrolateral sclerite.
Measurements
See Table 4.
Remarks
This specimen has red antennae, like the Cameroon females of Ramme’s apicalis rubroantennatus, but unlike them also has a red abdomen, similar to that of the female holotype of apicalis – we speculate that this was the main reason he used that name. Ramme had no other Cameroon males – his only other male (which he named a paratype) was from very distant Faradje (DR Congo) – see p. 97. We now know that the female paratypes of Ramme’s series belong to a Cameroonian population, the males of which differ considerably from his holotype (no red on abdomen and a different epiphallus) and are clearly a different species, described below (p. 77) as P. erythrocerus sp. nov.
There is no evidence that Ramme’s specimens share anything more than generic characters with Bolívar’s apicalis, so we propose that this name be dropped from Ramme’s taxon and that it be raised to full specific rank, giving the name P. rubroantennatus Ramme, 1929 stat. nov. for his holotype.
Status of taxonomic material
Poor. No female from the Cross River population is known. Further collections including females and a redescription are necessary. To date, due to ongoing hostilities in Cameroon, we have not been able to access the Cross River area for a modern collection.
Distribution
The unique male holotype defines the type locality. Ossidinge Station was a now vanished German colonial military post near the Nigerian border, between the villages of Agborkum and Oban, about 30 km downriver from the present-day town of Mamfe. Mamfe replaced Ossidinge in 1909, and was originally known to the German administration as Ossidinge II (https://en.wikipedia.org/wiki/Ossidinge, accessed Nov. 2023). It is quite possible that this species extends from the type locality downriver into Nigeria or south into the (Cameroonian) Korup Forest reserve. At Mamfe, 30 km upstream from the type locality, we have recently found a different species of this genus, P. sobrius sp. nov. (see p. 85), but not P. rubroantennatus.
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 30-33, DOI: 10.5852/ejt.2025.986.2853, http://zenodo.org/record/15235428