Kinixys erosa (Schweigger 1812) – Forest Hinge-back Tortoise, Serrated Hinge-back Tortoise, Serrated Hinged Tortoise.

Abstract

summary. -The Forest Hinge-back Tortoise, Kinixys erosa (Family Testudinidae), is a forest tortoise with considerable range over the continuous Guinea-Congo rainforest region in West and Central Africa. It is a medium-sized to large tortoise, with a carapace length reaching ca. 400 mm, and males larger than females. Tortoises of the genus Kinixys can close themselves entirely within their shells through a unique posterior carapacial hinge. Kinixys erosa inhabits the lowland evergreen forest, marshy areas, and forest galleries growing along rivers and streams, where it is locally threatened by clearance of forest for cultivation and hunting pressure. It has an omnivorous diet, with mushrooms being predominant. Population sizes are strongly depressed in areas where these tortoises are actively hunted by human populations. The main threats for this species include subsistence hunting by local people in desperately poor economic conditions, agricultural and industrial expansion with deforestation, and trade for the pet industry. There is a strong need for more field research on K. erosa ecology, abundance, and status. There are no known conservation actions for this species; however, there is a need to establish protected areas that include viable populations of these tortoises through their natural range.

Wild chimpanzees (Pan troglodytes troglodytes) exploit tortoises (Kinixys erosa) via percussive technology

“…One explanation may be that the ecological niche of chimpanzees only rarely overlaps with that of hinge-back tortoises. Hinge-back tortoises show a relatively rich ecological diversity and are found in lowland evergreen forest, marshy areas, and gallery forests growing along rivers and streams 42–44 . For instance, Vonesh 44 reported that hinge-back tortoises are widely distributed throughout Uganda, but seem to be absent from intact forest areas with relatively high densities of chimpanzees such as the Kibale National Park.…”

“…Forest hinge-back tortoises (Family Testudinidae) are medium- to large-sized reptiles with a carapace of approximately 400 mm length (weighing about 600–1500 g) 42,43 . Males are larger than females.…”

“…Hinge-back tortoises inhabit lowland evergreen forest, marshy areas, and gallery forests growing along rivers and streams with a considerable distribution over the continuous Guinea–Congo rainforest region in West and Central Africa. They are one of the most common tortoise species in Gabon, with an omnivorous diet mainly consisting of mushrooms 42,43 .…”

“…In addition, whenever possible we recorded the predation events via digital cameras (Canon Legria HF M41) and/or smart phones. The identification of the tortoise species was achieved by ET and TD comparing carapaces with published descriptions on tortoises in National Parks of Gabon 42,43,66 .…”

Knowledge gaps and conservation priorities for west African chelonians

“…The presence of C. senegalensis (one of three Trionychids in our analyses and a species listed as VU by the IUCN; Diagne et al, 2016) near the top of our conservation priority analysis may be viewed as a potential shortcoming of our methodology when compared with the lower placement of species with EN statuses, such as K. erosa and C. sulcata (Luiselli and Diagne, 2014;. However, while C. senegalensis is known to be one of the more common species in many of the places it has been sampled (Senegal: McGovern, unpublished data; South Sudan: Demaya et al, 2019;Benin: Luiselli et al, 2020;Ghana: Gbewaa et al, 2021;Nigeria: Luiselli, Akani and Eniang, unpublished data) this is not the first analysis in which it has received a high threat ranking (Luiselli, 2009).…”