Paraxerus cooperi Hayman, 1950

Denys, Christiane, Missoup, Alain Didier, Nicolas, Violaine, Fülling, Olaf, Delapré, Arnaud, Bilong, Charles Felix Bilong, Taylor, Peter John J. & Hutterer, Rainer, 2014, African highlands as mammal diversity hotspots: new records of Lamottemys okuensis Petter, 1986 (Rodentia: Muridae) and other endemic rodents from Mt Oku, Cameroon, Zoosystema 36 (3), pp. 647-690 : 679-683

Paraxerus cooperi Hayman, 1950

Paraxerus cooperi Hayman, 1950: 262 .

TYPE LOCALITY. — Cameroon, Rumpi Hills.

MATERIAL EXAMINED. — MNHN: CAM 318, 2013-121, 2013-122.

ZFMK: Eisentraut collections (78.50, 78.59, 78.54, 69.335 to 69.339, 69.341 to 69.347, 69.349 to 69.357, 69.377.

ZFMK: Fülling collection 91.220.

Morphological characters

This green olive squirrel is characterized by a long pelage and a HB size about 190 mm (according to Rosevear 1969 ’s key, Table 12). Paraxerus cooperi was placed in the genus Aethosciurus Thomas, 1916 by Moore (1959), and in a new subgenus Montisciurus Eisentraut, 1976 by Eisentraut (1976) based on palatal ridges features. According to this author, P. cooperi has seven palatal ridges, instead of four to five in P. poensis . A male and a female were trapped by local guides. The skull, teeth and size characters allow us to attribute the new specimens to P.cooperi .

DISCUSSION

FAUNAL LISTS COMPARISONS

In total, our respective surveys allowed to capture 26 species on Mt Oku. Of these species, 12 were intially reported by Eisentraut (1968, 1973). Thirty species were listed by Maisels et al. (2001), who used a previous list by Hutterer & Fülling (1994). Due to their large size Anomaluridae Gervais, 1849 , Hystricidae G. Fischer, 1817 , and Thryonomyidae Pocock, 1922 were not sampled during our study, in contrast to the study of Maisels et al. (2001) ( Table 13). Our 2005-2008 trapping sessions were focused in mountain forest above 2500 m, while Fülling (1992) also investigated lower altitude zones of Oku and found R. rattus , Mus musculus , Mastomys sp. and G. kempi in anthropogenic habitats close to Oku village at around 2000 m. Similarly, we did not collect Stochomys longicaudatus (Tullberg, 1893) which is considered a lowland forest rodent species, restricted to an altitude below 900 m ( Eisentraut 1963, 1973). This species was reported in Maisels et al. (2001). Eisentraut (1963, 1973) considered Cricetomys and Dasymys low altitude rodents, but the two genera were also recovered on Mt Oku at altitudes between 2200 and 2700 m. Cricetomys specimens are also known from higher elevation (1900 m) in Mt Kupe ( Denys et al. 2009). On Mt Oku, Hylomyscus walterverheyeni reaches 2500 m, while it was trapped at 1500 and 2000 m on Mt Kupe ( Denys et al. 2009; Missoup et al. 2009). Dendromus has not been collected previously on Mt Oku and for the first time we report the genus for all of the Bamenda Highlands. Funisciurus leucogenys is also mentioned for the first time on Mt Oku, but it was previously known to occur in Bamenda ( Eisentraut 1968).

On Mambilla Plateau (Mt Gangirwal), Nikolaus & Dowsett (1989) and Hutterer et al. (1992) recorded O. occidentalis and P. obscurus Hutterer and Dieterlen, 1992 . Missoup et al. (2012) confirmed the validity of P. hartwigi and suggested further investigations for P. obscurus pending a definitive conclusion on his specific status. Fülling (1992) already mentioned the presence of P. hartwigi and P. jacksoni on Mt Oku based on old Eisentraut material. Hutterer et al. (1992) indicated the presence of L. striatus , G. poensis , M. setulosus , L. sikapusi and Mastomys sp. in the Gotel Mountains (Southeast Nigeria) and Riegert et al. (2007) also found these species in owl pellets on Mt Bambili. In the present survey, we recorded these species on Mt Oku. In the Gotel Mountains and Mt Mambilla, as well as in Mt Bambili, Hutterer et al. (1992) and Riegert et al. (2007) also collected Mus of the minutoidesmusculoides species complex. In the present study we confirm the presence of three Hylomyscus species on Mt Oku: H. grandis , H. alleni cf. montis and H. walterverheyeni . The status of H. alleni cf. montis is not yet clarified and is awaiting a general revision of the H. alleni complex. Riegert et al. (2007) and Fülling (1992) obtained Dasymys remains in owl pellets. Based upon cranio-dental characters they attributed the specimens to D. rufulus , but we could not reach the same conclusion for the

Riegert et al. Hutterer et

Eisentraut 2007 al. 1992 Hutterer &

this work 1957-1973 Bamenda Gotel Mts Joger 1982 Maisels et al. Oku Oku highlands Mambilla Adamaoua 2001

Graphiurus murinus haedulus °

Dollman, 1912

Graphiurus lorraineus ° °

Dollman, 1910

Cricetomys gambianus °

Waterhouse, 1840

Cricetomys sp. ° C. emini ° Wroughton,

1910 s. l.

Dasymys sp. ° D. rufulus D. incomtus D. rufulus Miller, 1900 (Sundevall, Miller, 1900 1847)

Dendromus sp. °

Hybomys eisentrauti Van der ° ° °

Straeten & Hutterer, 1986

Otomys occidentalis ° ° ° ° °

Grammomys sp. ° °

Grammomys poensis ° ° ° °

Aethomys hindei Thomas, 1902 °

Gerbilliscus validus ° °

Bocage, 1890

Oenomys hypoxanthus ° ° ° °

albiventris Eisentraut, 1968

Lemniscomys striatus ° ° ° ° °

(Linnaeus, 1758)

Lemniscomys mittendorfi ° ° °

Eisentraut, 1968

Lophuromys sikapusi ° ° ° ° ° °

(Temminck, 1853)

Lophuromys dieterleni ° °

Verheyen, Hulselmans,

Colyn & Hutterer, 1997

Mus setulosus Peters,1876 ° ° ° ° ° °

Mus musculoides Temminck , ° ° ° °

1853

Mus musculus Linnaeus, 1758 °

Mastomys sp. ° ° ° ° °

Mylomys dybowskii ° °

(Pousargues, 1893)

Praomys jacksoni ° ° ° °

(de Winton, 1897)

Praomys hartwigi Eisentraut, 1968 ° ° ° °

Praomys obscurus °

Hutterer & Dieterlen, 1992

Uranomys ruddi Dollman, 1909 °

Hylomyscus walterverheyeni °

new specimens catpured on Mt Oku. Compared to the Mt Adamaoua faunas ( Hutterer & Joger 1982) we were unable to recover the savannah genera like Uranomys Dollman, 1908 , Aethomys Thomas, 1915 or Cryptomys Gray, 1864 . This may be related to the presence of a rather pervasive mountain forest vegetation in South Cameroon compared to the more arid northern parts of the Cameroon Volcanic line.

IMPORTANCE OF MT OKU FOR CONSERVATION

In the present work we recovered four strictly endemic rodent species of Mt Oku: Lamottemys okuensis , Hylomyscus grandis , Lophuromys dieterleni and Lemniscomys mittendorfi . These rare rodents are classified as Endangered or Critically Endangered by IUCN (2012) because: 1) they live only on the mountain forest slopes of Mt Oku; and 2) the degradation of the forest implies their population decrease ( Table 14). For the first time we recorded the presence of Dendromus on this mountain, which may represent new endemic species. We also found three of the Bamenda highlands endemics ( P. hartwigi , H. eisentrauti , O. occidentalis ), classified as endangered or vulnerable ( IUCN 2012). For squirrels, we found for the first time Funisciurus leucogenys and new specimens of Paraxerus cooperi on Mt Oku, both considered Data Deficient ( Table 14). Such exceptional level of endemism for Mt Oku has no equivalent in Africa, except maybe for Mt Cam - eroon and the highlands of East Africa. No endemic rodent genus occurs on Mt Cameroon, although five endemic species are known from this mountain ( D. oreas Osgood, 1936 , H. badius , D. bentleyae (Thomas, 1892) , O. burtoni , L. roseveari Verheyen, Hulselmans, Colyn & Hutterer, 1997 ) and their morphological and genetic differences from species of the same genera from Mt Oku are attested ( Missoup 2010; Taylor et al. 2014). The closest mountains to Oku are the Gotel Mountains, which do not harbour any endemic genera but share one of the Bamenda highlands endemic species ( O. occidentalis ). Looking eastwards, the nearest similar altitudinal zones are found in Central Africa, in the Western margin of the western Rift or in the East African Rift ( Ethiopia, Kenya, Tanzania). The Kivu Mountains ( Rahm & Christiaensen 1963) yielded no endemic genus and five endemic species ( Cricetomys kivuensis Lönnberg, 1917 , Lophuromys aquilus (True, 1892) , L. rahmi, Verheyen, 1964 , Dendromus kahuzensis Dieterlen, 1969 , Grammomys dryas Thomas, 1917 ). In the Virungas ( Verschuren et al. 1983), there is one endemic genus ( Delanymys Hayman, 1962 ) and four endemic species ( Dasymys rwandae W. Verheyen, Hulselmans, Dierck, Colyn, Leirs & Verheyen, 2003 , Otomys typus (Heuglin, 1877) , Lophuromys luteogaster Hatt, 1934 , Praomys verschureni Verheyen & Van der Straeten, 1977 . The Ruwenzori highlands ( Misonne 1963) harbour three endemic species ( Otomys dartmouthi Thomas ,

Rodentia This work Anterior works IUCN status Vernacular name

Cricetomys sp. ° NA Forest giant pouched rat

Cricetomys emini ° LC Forest giant pouched rat Wroughton, 1910 sensu lato

Cricetomys gambianus ° LC Northern giant pouched rat Waterhouse, 1840

Dasymys sp. ° NA

Dasymys rufulus Miller, 1900 ° DD West African Dasymys

Dendromus sp. ° NA Climbing mouse

Funisciurus leucogenys ° LC Red-cheeked rope squirrel (Waterhouse, 1842)

Gerbilliscus kempi ° ° LC Kemp’s Gerbil

(Wroughton, 1906)

Grammomys poensis ° ° LC Western rainforest thicket rat Eisentraut, 1965

Grammomys sp. ° ° NA

Graphiurus lorraineus ° ° LC Lorrain’s dormouse

Dollman, 1910

Hybomys eisentrauti ° ° E Eisentraut’s stripped mouse Van der Straeten & Hutterer, 1986

Hylomyscus alleni cf. montis ° ° LC Allen’s Hylomyscus Eisentraut, 1969

Hylomyscus grandis ° ° CR Mt Oku Hylomyscus Eisentraut, 1969

Hylomyscus walterverheyeni ° NA Verheyen’s Hylomyscus Nicolas, Wendelen, Barrière,

Dudu & Colyn, 2008

Lamottemys okuensis ° ° E Mount Oku rat

Petter, 1986

Lemniscomys mittendorfi ° E Mittendorf’s stripped mouse Eisentraut, 1968

Lemniscomys striatus ° ° LC Typical stripped mouse (Linnaeus, 1758)

Lophuromys dieterleni Verheyen , ° ° E Mount Oku brushed-fur rat Hulselmans, Colyn & Hutterer,

1997

Lophuromys sikapusi ° LC Rusty-bellied Brush-furred Rat (Temminck, 1853)

Mastomys sp. ° LC Multimammate rat

Mastomys natalensis Smith, 1834 ° LC Natal Multimammate rat

Mus setulosus Peters, 1876 ° ° LC Peter’s pygmy mouse

Mus musculoides Temminck, 1853 ° CR Subsaharan Pygmy Mouse

Mus musculus Linnaeus, 1758 ° LC House mouse

Mylomys dybowskii ° ° LC Dybowski’s three-toed grass (Pousargues, 1893) rat

Oenomys hypoxanthus albiventris ° ° LC Common rufous-nosed rat Eisentraut, 1968

Otomys occidentalis ° V Western vlei rat

Dieterlen & Van der Straeten, 1992

Paraxerus cooperi Hayman, 1950 ° ° DD Cooper’s mountain squirrel

Praomys hartwigi Eisentraut, 1968 ° ° E Hartwig’s soft furred mouse

Praomys jacksoni (de Winton, 1897) ° ° LC Jackson’s soft furred mouse

Rattus rattus (Linnaeus, 1758) ° LC Roof Rat

Thryonomys swinderianus ° LC Greater Cane Rat

Temminck, 1827

Xerus erythropus Geoffroy, 1803 ° LC Striped Ground Squirel

1906, Dasymys montanus Thomas, 1906 , Hybomys lunaris Thomas, 1906 ). Stanley & Goodman (2011) recently described Hylomyscus arcimontensis from the Usambara ( Tanzania). Taylor et al. (2011) identified Otomys jacksoni from Mt Elgon. Hylomyscus vulcanorum Lönnberg & Gyldenstolpe, 1925 was reported for the first time from the highlands of Eastern Africa by Carleton et al. (2006). The highest level of endemicity is found in the Ethiopian highlands where five genera ( Muriculus Thomas, 1903 , Megadendromus Dieterlen & Rupp, 1978 , Nilopegamys Osgood, 1928 , Desmomys Thomas, 1910 , Stenocephalemys Frick, 1914 ) and about 12 species or subspecies ( Lophuromys brevicaudus Osgood, 1936 , L. chrysopus Osgood, 1936 , L. melanonyx Petter, 1972 , L. brunneus Thomas, 1906 , Mus mahomet Rhoads, 1896 , Mus tenellus ( Thomas, 1903) , Mus setulosus , Grammomys minnae Hutterer & Dieterlen, 1984 , Dendromus lovati de Winton, 1900 , Mylomys rex (Thomas, 1906) , Desmomys harringtoni (Thomas, 1902) , D. yaldeni Lavrenchenko, 2003 , are endemic ( Yalden et al. 1996; Lavrenchenko 2000). However, the Ethiopian highlands occupy a much wider area than Mt Oku and are constituted of different massifs harbouring various endemic species.

The exceptional importance of Mt Oku for conservation is shared by other taxa. An endemic subspecies of golden mole, Chrysochlorys stuhlmanni balsaci Lamotte & Petter, 1981 , was described recently. The level of endemicity is also remarkable for other vertebrates like Amphibians, with the endemic species Phrynobatrachus chukuchuku Zimkus, 2009 and the Lake Oku Clawed Frog Xenopus longipes Loumont & Kobel, 1991 . Many plants ( Cheek et al. 2000; Maisels et al. 2000) and birds (like Tauraco bannermani Bates, 1923 and Platysteira laticincta Bates, 1926 ) occur only on Mt Oku and in the Bamendas Highlands ( Smith et al. 2000; Njabo & Sorenson 2009).

Compared to Mt Cameroon, Mt Oku has a different rodent faunal composition, despite its relative geographic close proximity: 1) both volcanoes only have three species in common ( Mus setulosus , Hylomyscus walterverheyeni , Funisciurus leucogenys ); and 2) they are characterized by different endemic species ( Table 15, Fig. 12). In this work the presence of some endemic rodents reported in the Bamenda highlands (Lefo and Gotel-Mambilla mountains) was confirmed from Mt Oku, validating some previous biogeographical suggestions. Hutterer et al. (1992), for example, reported the close relationship between Mt Kupe and Mt Cameroon on one side, between Mt Oku, Mt Lefo and Mt Manengouba on the other side, and the geographical distinctiveness of Gotel and Mambilla mountains in respect to rodent and shrew faunas. The distinction between Bamenda highlands region in the north of the CVL (including Mt Lefo - Mt Oku) and Mt Cameroon (including Mt Kupe - Rumpi Hills) in the south seems consistent with different histories of these mountains, which represent islands of high altitude vegetation. A similar pattern has been recovered for birds ( Smith et al. 2000). Clearly some Oku endemics, like Otomys occidentalis and Lamottemys okuensis , indicate eastern and southern African affinities, and possibly an old wave of colonisation for eastern highlands ( Missoup 2010; Taylor et al. 2014). Other endemics, like those in the genus Praomys , would have differentiated from lowland forests taxa during the Pleistocene ( Missoup et al. 2012). This biogeographic pattern may be related to the older age of Bamenda Highlands volcanoes (which originated as early as 31-28 Ma; Marzoli et al. 2000) compared to the more recent Mt Cameroon (9 Ma; Fitton & Dunlop 1985) and Mt Kupe (1 Ma; Wild 2004).