Taxonomy of the African giant pouched rats (Nesomyidae: Cricetomys): molecular and craniometric evidence support an unexpected high species diversity

Abstract

Our study combined a mitochondrial cytochrome b phylogeny with cranial measurements from giant pouched rats collected across sub‐Saharan Africa. The mitochondrial phylogeny resolves two West African clades and a clade with east and central Africa representatives. This last clade can be further divided into four subclades. Altogether they represent six species (Cricetomys gambianus, Cricetomys ansorgei, Cricetomys emini, and three undescribed taxa) that can be distinguished on the basis of their mitochondrial DNA sequences and craniometry. In the absence of adequate craniometric data the existence of Cricetomys kivuensis cannot be confirmed by our data. Our combined molecular and craniometric data allowed us to broadly delineate the distribution ranges of the detected species. Cricetomys gambianus occurs in the savannah and forest clearings of West Africa. Cricetomys ansorgei is distributed in the savannah of East and southern Africa. Cricetomys emini, as currently recognized across the Guineo‐Congolian forest of Africa, is shown to be diphyletic. Cricetomys sp. 1, a separate operational taxonomic unit closely resembling C. emini, occurs in the forest zone of West Africa. An undescribed sister‐species of C. ansorgei, Cricetomys sp. 2, occurs in the forest of Central Africa along the left bank of the Congo River. Cricetomys sp. 3 occurs on the right bank of the Congo River from Cameroon to the Republic of Congo, whereas the true C. emini also occurs on the right bank of the Congo River but appears to be restricted to the Democratic Republic of Congo. Cranial phenotype within the genus tends to conform to ecological zonation (either forest or savannah) rather than to phylogenetic affiliation of the species concerned, suggesting that diversifying selection across environmental gradients could be responsible for biological diversification within the genus.

Morphometry and DNA barcoding reveal cryptic diversity in the genus Enteromius (Cypriniformes: Cyprinidae) from the Congo basin, Africa

“…A similar approach applied to other tropical vertebrates has yielded similar results. For instance, in a study on African giant pouched rats (Cricetomys, Nesomyidae), the combined use of DNA barcoding and cranial measurements lead to the discovery of at least three new species (Olayemi et al 2012). Also for the fish genus Pseudobarbus (Cyprinidae) occurring in southern Africa, 15 separate lineages were identified, using cytb and 16S data, within the (at that time) seven valid species within the genus, most of which were confirmed by morphological results (Swartz et al 2009).…”

“…However, the uncritical use of molecular tools to identify species, especially using only a single molecular locus (mt genome), is unwarranted (DeSalle et al 2011), and traditional morphology has proven its value as a suitable technique to assess the diversity in many taxa. Therefore, we combined both methodologies in the present study, an approach that has already proven to be successful in several taxonomic studies (e.g., Olayemi et al 2012;Stiassny et al 2013;Lavoué & Sullivan 2014).…”

High Prevalence of Rickettsia typhi and Bartonella Species in Rats and Fleas, Kisangani, Democratic Republic of the Congo

“…Because of its strategic position, this market provides the majority of the sylvatic products (including bushmeat) sold in town. 24 The TM (0 31 N, 25 11 E), consists of open air stalls and warehouses and is situated in the popular Tshopo district (100,000 inhabitants). Hygienic conditions are on the whole poor (lack of proper drainage of sewage, garbage disposal, or septic tanks) for cohabiting families living on and around the market places.…”

“…Because of this intensifying human encroachment into natural ecosystems, the risk of importing exogenous zoonotic pathogens could raise. 23,24 Moreover, traders and consumers of the central market claimed to regularly consume rodents captured in their own homesteads (Falay A, unpublished data). Finally, because of its fluvial connection with Kinshasa, the potential influx of rats infested with Xenopsylla cheopis fleas, a known vector of murine typhus (R. typhi) is a true concern.…”

Morphometrical and genetic comparison of two nematode species: H. spumosa and H. dahomensis (Nematoda, Heterakidae)

“…Subsequently, Boulenger (1923) reported this nematode from Zanzibar (Tanzania) in C. gambianus (although Olayaemi et al (2012) cast doubt on the identification of the Cricetomys species in question) and provides measurements and drawings. Hall (1916) synonymised H. dahomensis with H. spumosa, which was cited posteriorly by Baylis (1928) as H. spumosa from C. gambianus (C. gambianus or, according to Olayemi et al (2012), Crice- Table I. Measurements of male Heterakis spp.…”