Findings on the synonyms of Trioceros ituriensis
Synonyms for the Congolese Ituri chameleon (Trioceros ituriensis) have existed for several decades. A recent publication by the herpetologist Wolfgang Böhme questions whether two of them could be separate species.
The US herpetologist Karl Patterson Schmidt described the chameleon as Chamaeleon ituriensis in 1919. At that time, Schmidt gave Medje, Ituri Forest, in the Democratic Republic of Congo as the type locality. He already noticed the external similarity to Chamaeleon johnstoni affinis, which is why he gave exactly that as a synonym of his Chamaeleon ituriensis. At the same time, Chamaeleon johnstoni affinis must not be confused with today’s Trioceros affinis, a separate species from Ethiopia that had already been described in 1845. In the course of the 20th century, Chamaeleo johnstoni affinis was placed in the genus Trioceros, sometimes thought to be a subspecies of its own, sometimes not. Böhme states that Trioceros johnstoni affinis is definitely a synonym of Trioceros ituriensis. Differences between Trioceros johnstoni and Trioceros ituriensis are the body size, the “reversed” sexual dimorphism (in T. ituriensis the females are larger than the males), a white line along the belly, several rows of enlarged scales along the side of the body, conical scales on the sides of the throat and the absence of rostral and preocular horns in male T. ituriensis.
However, the author is not sure about the species status of Chamaeleo laevigularis. The species was originally described from South Africa in 1926, then considered a synonym of Trioceros johnstoni and last identified as T. ituriensis by Tilbury in 2010. Böhme considers, because of different scaling of the throat, whether either a wrong locality was noted in the first description or it is a separate species, but could be extinct or lost.
Böhme also comes to the conclusion that Trioceros tremperi, which was described by Neĉas in 1994, could possibly also represent an already extinct species or a lost species and that the locality simply corresponded to incorrect information. Trioceros tremperi was last given as a synonym of Trioceros ituriensis by Tilbury 2010 and Spawls 2018. The chameleons had not been found in the type locality in Kenya before.
Documenting synonymies in Trioceros ituriensis (Schmidt, 1929) with remarks on sexual dimorphism in chameleons (Squamata: Chamaeleonidae)
Revue Suisse de Zoologie 130(2), 2023: pp. 521-264
Photo: Trioceros ituriensis in the Budongo forest, Uganda, photographed by Katja Rembold