During these 12 days of surveying in Ghana, we only encountered two Gomphidae: Gomphidia gamblesi and P. serrulatus, both on the same river about twenty meters apart, whereas the country has around twenty species. This is certainly a very low score, which can be explained by the choice of forest habitats we explored.
There is no risk of confusing it with another Gomphidia, as it is the only one of its genus in the country. On the other hand, it is close to Diastatomma gamblesi, from which it is easily distinguished by its anal appendages, which here are pincer-shaped; the cerci (superior anal appendages) are strongly curved inward and upturned at their tips, whereas those of D. gamblesi are very different and curved downward. In English, it takes the name Western Fingertail; it is the sole representative of the genus in West Africa, and the shape of the anal appendages in this genus is likened to a finger, a feature not so obvious for this species, though no doubt more so for the other two, including G. quarrei, which I had encountered in Namibia.
Gauthier (1987) tells us that its abdomen measures 42 to 46 mm, which gives a total length of about 56 mm. According to Legrand (2003), it frequents medium-sized forest streams. We encountered it in a very narrow constriction, a kind of dead end (the upstream being inaccessible due to exuberant vegetation from fallen trees) of a heavily shaded river 6 to 8 meters wide. Having spotted an odonate flying in this more open part, one of my companions had wisely stuck a branch into the water! It remained on this perch for only a few seconds, and the long wait endured by my companions was scarcely rewarded (I arrived at the right moment, but I only have a few photos, all from the same angle).
It is found from Guinea, Sierra Leone, and Liberia to Cameroon, although it is not confirmed in Nigeria. (ADDO).
IUCN Red List.
Etymology of Gomphidia gamblesi
Gomphidia, from gomphus derived from a Greek word meaning a peg or bolt, referring to the shape of the abdomen (in most species), which resembles a peg used for assembling boats. And from idios, which means separate, distinct, because this genus is distinguished from Gomphus by several characteristics, including the expansion of S8. Gamblesi is a tribute to Robert Moylan Gambles (1910–1990), an eminent British veterinarian and entomologist, particularly recognized for his expertise on odonates, for the assistance provided in the description of this species.
Gauthier A., 1987 - Description d'une nouvelle espèce de Gomphidae du Togo (Afrique Occidentale) Gomphidia gamblesi spec.nov. (Odonata). Bulletin Société entomologique Mulhouse, 3, 41-44.
Legrand, 2003 – Les Odonates du Nimba et de sa région in LAMOTTE M. & ROY R. (eds), Le peuplement animal du mont Nimba (Guinée, Côte d’Ivoire, Liberia). Mémoires du Muséum national d’Histoire naturelle 190 : 231-310, p. 260.