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| Chingawaemys Lavrenchenko, Mikula & Bryja, gen. nov. Congomys Nicolas & Bryja, gen. nov. Ochromyscus Nicolas, Mikula & Bryja, gen. nov. Serengetimys Nicolas & Bryja, gen. nov. Montemys Nicolas & Bryja, gen. nov. in Nicolas, Mikula, Lavrenchenko, Šumbera, Bartáková, Bryjová, Meheretu, Verheyen, Missoup, Lemmon, Lemmon et Bryja, 2021. |
Highlights:
• Fully resolved phylogeny of a highly diversified group of African mammals using genome-scale data.
• Mechanisms of adaptive radiation in Late Miocene/Early Pliocene.
• Delimitation of monophyletic genera in Praomyini rodents.
• Discovery of a new mammal genus in Ethiopian forests.
Abstract
The tribe Praomyini is a diversified group including 64 species and eight extant rodent genera. They live in a broad spectrum of habitats across whole sub-Saharan Africa. Members of this tribe are often very abundant, they have a key ecological role in ecosystems, they are hosts of many potentially pathogenic microorganisms and comprise numerous agricultural pests. Although this tribe is well supported by both molecular and morphological data, its intergeneric relationships and the species contents of several genera are not yet fully resolved. Recent molecular data suggest that at least three genera in current sense are paraphyletic. However, in these studies the species sampling was sparse and the resolution of relationships among genera was poor, probably due to a fast radiation of the tribe dated to the Miocene and insufficient amount of genetic data. Here we used genomic scale data (395 nuclear loci = 610,965 bp long alignment and mitogenomes = 14,745 bp) and produced the first fully resolved species tree containing most major lineages of the Praomyini tribe (i.e. all but one currently delimited genera and major intrageneric clades). Results of a fossil-based divergence dating analysis suggest that the radiation started during the Messinian stage (ca. 7 Ma) and was likely linked to a fragmentation of the pan-African Miocene forest. Some lineages remained in the rain forests, while many others adapted to a broad spectrum of new open lowland and montane habitats that appeared at the beginning of Pliocene. Our analyses clearly confirmed the presence of three polyphyletic genera (Praomys, Myomyscus and Mastomys). We review current knowledge of these three genera and suggest corresponding taxonomic changes. To keep genera monophyletic, we propose taxonomic re-arrangements and delimit four new genera. Furthermore, we discovered a new highly divergent genetic lineage of Praomyini in southwestern Ethiopia, which is described as a new species and genus.
Graphical abstract
Keywords: Late Miocene, Radiation, Anchored phylogenomics, Rodentia, Tropical Africa, Complete mitochondrial DNA, Taxonomy
Praomys Thomas, 1915
Montemys Nicolas & Bryja, gen. nov.
Type species: Epimys delectorum Thomas, 1910.
Ann. Mag. Nat. Hist., ser. 8, 6: 430.
Etymology: The new generic name is a masculine noun composed of Latin “montem” (mountain) and greek “mys” (mouse). Oldfield Thomas described the type species of this genus in 1910 from S Malawi, Mulanje (=Mlanji) Plateau, 5500 ft., and all known populations of the genus are known to live in montane forests of Eastern Africa (Bryja et al., 2014, Carleton and Stanley, 2012).
Species included: Montemys delectorum (Thomas, 1910).
English name: Several names were previously proposed for this species: Delicate Soft-furred Mice, Delectable Soft-furred Mouse, Delicate Praomys and East African Praomys (Wilson et al., 2017). Given that it is no longer included in the genus Praomys and that the term “soft-furred” is usually used for Praomys species, we propose to use the name Delicate Montane Mouse for Montemys delectorum.
Congomys Nicolas & Bryja, gen. nov.
Type species: Praomys tullbergi lukolelae Hatt, 1934.
Am. Mus. Novit., 708: 13.
Etymology: The new generic name is a masculine noun composed of “Congo” (geographical name) and “mys” (=mouse). The name acknowledges the Congo Basin, where the two currently known species of this genus are endemic.
Species included: Congomys lukolelae (Hatt, 1934);
Congomys verschureni (Verheyen & Van der Straeten, 1977).
English names: Several names were previously proposed for C. lukolelae (Lukolela soft-furred mouse, Lukolela Praomys and Lukolela Swamp rat) and C. verschureni (Verschuren’s Praomys or Verschuren Swamp rat) (Wilson et al., 2017). Given that these species are no longer included into the genus Praomys and that the term “soft-furred” is usually used for Praomys species, we propose using the names Lukolela Swamp rat for C. lukolelae and Verschuren’s Swamp rat for C. verschureni.
Myomyscus
Species included: M. verreauxii (Smith, 1834)
English name: The names Verreaux’s Meadow Mouse, Verreaux’s Myomyscus, Verreaux’s White-footed Rat and White-footed Mouse are commonly used for this species (Wilson et al. 2017). We propose to retain the name Verreaux’s Meadow Mouse for this species.
Ochromyscus Nicolas, Mikula & Bryja, gen. nov.
Type species: Mus brockmani Thomas, 1906.
Ann. Mag. Nat. Hist., ser. 7, 18: 298.
Etymology: The new generic name is a masculine noun composed of “ωχρος” [ochros] (which means “pale” in Greek) and “myscus” (derived from myskos = small mouse, diminutive of mys = mouse). The name acknowledges the typical color of these rodents, which has no bright hue.
Species included: Ochromyscus brockmani (Thomas, 1906);
Ochromyscus yemeni (Sanborn & Hoogstraal, 1953).
English name: We propose the name White-bellied Rocky mouse, because the purely white belly is typical of all species within this genus and they are most abundant in rocky outcrops.
Serengetimys Nicolas & Bryja, gen. nov.
Type species: Rattus pernanus Kershaw, 1921.
Ann. Mag. Nat. Hist., ser. 9, 8: 568.
Etymology: The new generic name is a masculine noun composed of “Serengenti” (geographical name) and “mys” (=mouse). P. S. Kershaw described the type species of this genus in 1921 from Amala (=upper course of Mara) River in southern Kenya. All known records (except an aberrant specimen from Eastern Tanzania and an unconfirmed record from Rwanda) of this monotypic genus are from the so-called Serengeti ecosystem with prevailing grasslands in northern Tanzania and southern Kenya (Van der Straeten, 1999).
Species included: Serengetimys pernanus (Kershaw, 1921).
English name: Dwarf Serengeti mouse. Happold (2013) proposed the English name “Dwarf Multimammate Mouse”, because it was thought that the species belong to the genus Mastomys (“multimammate mice”). However, our first observation of a lactating female from southern Kenya revealed that they have only five pairs of nipples.
Mastomys
Mastomys angolensis (Bocage, 1890), comb. nov.
Species included: M. angolensis (Bocage, 1890), M. awashensis Lavrenchenko, Likhnova & Baskevich, 1998, M. coucha (Smith, 1834), M. erythroleucus (Temminck, 1853), M. huberti (Wroughton, 1909), M. kollmannspergeri (Petter, 1957), M. natalensis (Smith, 1834), M. shortridgei (St. Leger, 1933)
Chingawaemys Lavrenchenko, Mikula & Bryja, gen. nov.
Type species: Chingawaemys rarus,
the new species described below.
Etymology: The new generic name is a masculine noun composed of “Chingawa” (geographical name) and the Greek “mys”, referring to mouse, or rat in this case. The name acknowledges the Chingawa Forest, where the single known species of this genus is endemic.
Chingawaemys rarus Lavrenchenko, Mikula & Bryja, sp. nov.
Etymology: The species name is derived from the Latin word “rarus” – rare (see Ecology).
English name: We propose the vernacular name “Chingawa Forest Rat” for Chingawaemys rarus sp. nov. The name reflects that this rare rodent appears to be endemic to the unique Chingawa Forest.
Violaine Nicolas, Ondřej Mikula, Leonid A. Lavrenchenko, Radim Šumbera, Veronika Bartáková, Anna Bryjová, Yonas Meheretu, Erik Verheyen, Alain Didier Missoup, Alan R. Lemmon, Emily Moriarty Lemmon and Josef Bryja. 2021. Phylogenomics of African Radiation of Praomyini (Muridae: Murinae) Rodents: First fully resolved Phylogeny, Evolutionary History and Delimitation of Extant Genera. Molecular Phylogenetics and Evolution. 163, 107263. DOI: doi.org/10.1016/j.ympev.2021.107263