Ochromyscus niveiventris (Osgood, 1910)

Meheretu, Yonas, Mikula, Ondřej, Frynta, Daniel, Frýdlová, Petra, Mulualem, Getachew, Lavrenchenko, Leonid A., Kostin, Danila S., Elmi, Hassan Sh Abdirahman, Šumbera, Radim & Bryja, Josef, 2024, Phylogeny, biogeography, and integrative taxonomic revision of the Afro-Arabian rodent genus Ochromyscus (Muridae: Murinae: Praomyini), Zoological Journal of the Linnean Society 202 (1), pp. 1-15 : 13

(ii) Ochromyscus niveiventris (Osgood, 1910)

Snowy white-bellied rocky mouse. The Latin name ‘ niveiventris ’ means ‘snowy-white-bellied’. Because the English genus name is ‘white-bellied rocky mouse’ ( Nicolas et al., 2021), we propose to simplify the English name to avoid redundant use of ‘whitebellied’.

Mus niveiventris Osgood, 1910 , Field Museum of Natural History, Zoological series, 10(2), p. 12, 16 February 1910 (species description).

Mus niveiventris subfuscus Osgood, 1910 , Field Museum of Natural History, Zoological series, 10(2), p. 12, 16 February 1910 (subspecies description, type from Lake Elementeita, British East Africa, FMNH 16972).

Epimys niveiventris ulae Heller, 1910 , Smithsonian Misc. Coll., 56: no. 9, p. 3, pi. 2, 22 July 1910 (subspecies description, type from Ulu Kenia Hills, Kenya Colony, USNM 162887).

Praomys fumatus oweni Setzer, 1956 , Procs. US National Museum, Vol. 106, No. 3377, p. 525 (subspecies description, type MCZ 45883, adult male from Murukurun, 50 miles east of Torit, Anglo-Egyptian Sudan).

Myomyscus sp. ‘South’: Bryja et al. (2019) (overview of Ethiopian records, first recognition as a distinct species).

Holotype

FMNH 17099 ; adult female, collected by E. Heller, 22 April, 1906 .

Type locality

Voi, British East Africa (today Kenya).

Taxonomic notes

The species (O. sp. 3 in our study) is here retracted from synonymy with O. brockmani based on very deep genetic divergences ( Figs 2 and 4 ; see also: Nicolas et al. 2021) and skull morphology ( Fig. 6 ). Several names are available for this taxon that was for the first time reported as a separate species Myomyscus sp. ‘South’ by Bryja et al. (2019b). We included types of nive i ventris and subfuscus in the morphometric analysis of skulls and they cluster with this taxon (the former is the oldest available name). The names ulae and oweni were synonymized with brockmani (e.g. Musser and Carleton 2005), but they very likely represent O. niveiventris , considering the position of their type localities (see Figs 1 and 3 ). The species can potentially meet with O. brockmani in the central and southern part of the Ethiopian Great Rift Valley, but we have not documented any evidence of their sympatry.

Figures

Figure 1. Compilation of previous taxonomic and distributional data of Ochromyscus. Background colours represent distribution reported by IUCN Red List for O. (‘Myomyscus’) brockmani (blue) and O. (‘Myomyscus’) yemeni (green), downloaded on 31 May 2021. Blue dots show records of O. (‘Myomyscus’) brockmani from GBIF.org (31 May 2021) GBIF Occurrence Download https://doi.org/10.15468/dl.93ynrv, combined with additional published data from Sudan (Happold 1966), Ethiopia (Yalden et al. 1976), Somalia (Corti et al. 1999), and unpublished data based on vouchers in NHM London (from Somaliland) and MNHN (from Somalia).Green dots represent documented records of O. (‘Myomyscus’) yemeni from GBIF.org (31 May 2021) GBIF Occurrence Download https://doi.org/10.15468/dl.zfj6yh, combined with additional published data from Nader et al.(1983), Sanborn and Hoogstraal (1953), and Büttiker and Harrison (1982) and two vouchers in MNHN Paris (from Saudi Arabia). Red stars show type localities and available names for species of the genus Ochromyscus. Small yellow circles are localities, from which we collected the genetic data.

Figure 2. Bayesian phylogenetic tree of Ochromyscus calculated in MrBayes, based on mitochondrial Cytb sequences. The tree was rooted by the sequence of Mastomys awashensis. The topology of the main Ochromyscus clades was very similar in ML analysis in RAxML, but the monophyly of the genus was supported only in MrBayes (PP = 1.00). Black dots indicate posterior probability support>0.95 and ML bootstrap support>75; lower values are shown by numbers.

Figure 3. Distribution of genetic variability and taxonomic summary of the genus Ochromyscus. Different symbols show the distribution of three different species distinguished in this study:stars—O. yemeni, triangles—O. brockmani, circles—O. sp. 3 (=niveiventris; see text for more details); different colours show intraspecific mtDNA variability.Names of mtDNA clades correspond to Figure 2. Background colours represent the predicted distribution of O. (‘Myomyscus’) brockmani (blue) and O. (‘Myomyscus’) yemeni (green) according to the IUCN Red List. Dashed lines encompass clusters of genomically similar specimens identified by InfoMap based on ddRAD data, with corresponding suggested species names.Note that the populations with mtDNA of the ‘Arero’ and ‘Uganda’ clades were not included in the ddRAD analysis, but we assigned them to O. sp. 3 (=niveiventris) based on their morphology (see text for more details). Similarly, no samples of O. yemeni were available for the genomic analysis.The inset photo shows a picture of rocky habitats, typical for Ochromyscus in eastern Ethiopia.

Figure 4. Maximum likelihood phylogenetic tree (RAxML) inferred from the concatenated dataset of 66 577 loci (503 746 SNPs) genotyped by the ddRAD approach.Black dots show nodes with the maximum bootstrap support (BP = 100). Bars on the right side show delimitations of MOTUs from the branch-cutting of this ML tree and from the InfoMap clustering based on the co-ancestry matrix (shown in Fig.5).

Figure 6. The scatterplot of bgPC scores.The large, filled points mark species’ mean shapes, and small, open points are projections of individual shapes on to the axes. The projections of four holotype skull shapes are indicated by black points labelled by the respective names.