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Carleton, Michael D., Banasiak, Rebecca A., Stanley, William T. (2015): A new species of the rodent genus Hylomyscus from Angola, with a distributional summary of the H. anselli species group (Muridae: Murinae: Praomyini). Zootaxa 4040 (2): 101-128, DOI: http://dx.doi.org/10.11646/zootaxa.4040.2.1

Hylomyscus heinrichorum, new species (Figs. 5–7; Table 6) Hylomyscus carillus, Hill & Carter, 1941: 97 (part, faunal report); Crawford-Cabral, 1998: 79 (part, faunal report). Praomys carillus, Crawford-Cabral, 1986: 163 (part, name combination, zoogeography). Hylomyscus denniae, Musser & Carleton, 1993: 599, 2005: 1336 (part, systematic checklists, referenced as isolated population of indeterminate status).— Dieterlen, 2013: 435 (part, faunal report, distribution). H [lomyscus]. cf. anselli group, Carleton & Stanley, 2005: 629 (taxonomic revision, definition of the H. anselli species group and its contents). Holotype. FMNH 83796, an adult male prepared as skin and skull, captured 7 October 1954 (skin tag reads “ 7 X 1954 ”) by Gerd H. Heinrich; the field number is recorded on the skin tag as 8778 and as GH 8778 on the now loose skull tag. Machine-printed on back of the tag is “Angolan Zoological Expedition, 1954.” Written in black pen in the collector’s script are the external measurements (“T.L.: 245, Tail: 145, H.F.: 22, Ear: 19 ”) and habitat (“Evergreen wood. – High mountain region”); the testes were noted as scrotal in position. See Table 6 for cranial measurements of the holotype. The skin is well prepared, in fine condition, and the skull is intact, in good condition with minor damage confined to the left orbital wall. Type locality. Angola, Provincia Huambo, Mount Moco, ca. 12 ° 27.712 ʹS, 15 ° 10.600 ʹE (per the U.S. National Geospatial-Intelligence Agency). The locality as recorded on the skin tag reads only “ Angola, Mount Moco.” Heinrich collected at two localities on Mt Moco, as evidenced by locality modifiers recorded in the field catalog and by an annotated, X-marked field map accessioned with that catalog (both documents maintained in the FMNH Mammal Division). One X-marked site is centered near the peak of Mt Moco, and a second X is located nearby to the southeast. Specimens obtained at the latter place were labeled “foot” and collected 14–20 Sep 1954. Heinrch then relocated to a higher elevation and settled in a “high mountain region,” presumably corresponding to the former X, where he remained for over three weeks, 22 Sep– 16 Oct 1954. The type specimen and referred specimens from Mt Moco all originated from the high mountain locality. Paratypes. All material here assigned to H. heinrichorum originates from two localities in Angola, Provincia Huambo. These include 14 additional specimens from Mt Moco (FMNH 83793 –83795, 83797–83799, 83801– 83807, 83895), collected from 5–10 Oct 1954 by G. Heinrich; and 10 specimens from Mount Soque, 42 km WSW Luimbale (FMNH 83783–83792), collected 24–28 Aug 1954 by G. Heinrich. Heinrich’s Mount Soque (also as Serra Ussoque) is a ridge-shaped inselberg (12 ° 17.450 ʹS, 15 °08. 633 ʹE), located approximately 20 km NNW Mt Moco and 20 km WSW Luimbale, its peak elevation ca. 2165 m. We presume that Heinrich’s locality modifier, “ 42 km WSW Luimbale,” was a by-road calculation. Diagnosis. A species of the Hylomyscus anselli group characterized by larger size (ONL ≈ 26.0– 27.5 mm; CLM ≈ 4.1–4.3 mm) compared with examples of H. arcimontensis and H. kerbispeterhansi (ONL ≈ 24.5–26.5 mm; CLM ≈ 3.5 –4.0 mm), as reflected in most craniodental dimensions recorded (Table 6). Compared with examples of H. anselli, size comparable, but bony palate notably shorter with absolutely and proportionally longer incisive foramina (LIF ≈ 75–80 % of LD) that penetrate between the anterior roots of the first molars; molars slightly more robust and zygomatic plate broader; head-and-body and tail average shorter in length, and rostral dimensions (LR, LD) average smaller. Distribution. Restricted to high mountainous region of westcentral Angola as so far known (Fig. 4). Description and comparisons. Hylomyscus heinrichorum can be associated with the other species so far recognized in the H. anselli group (H. anselli, H. arcimontensis, H. kerbispeterhansi) based on certain qualitative traits. Foremost among these are the lack of pectoral mammae; the large expanse of the subsquamosal fenestrum, which together with the postglenoid foramen defines a slender and long hamular process (see Carleton & Stanley, 2005: Fig. 6); and its relatively shorter incisive foramina (namely, shorter in comparison with members of the H. denniae group). The number of mammary glands in H. heinrichorum —six, distributed as one post-axial pair and two inguinal pairs—was verified on several prepared round skins (FMNH 83793, 83795, 83802–83804), all females that were apparently in late-term pregnancy or lactating. Although we excluded external variables in our multivariate analyses, mean differences were highly significant for TOTL, TL, and HBL in one-way ANOVAs that compared our tabulated samples of H. heinrichorum and H. anselli (F values = 13.8–14.4, P H. heinrichorum averaged smaller than that of H. anselli for all three significantly different skin variables (Table 6). Our samples of the two species were obtained by different collectors, and such external variables are notoriously variable depending upon investigator habit and field experience. Even so, the disparity in means seems suitably large to convey real taxonomic differences. The pelage of H. heinrichorum resembles that observed in other members of the H. anselli group, being soft and fine in texture, short and closely adpressed to the body. The most notable pelage contrast of the Angolan form involves dorsal pelage color. Individual dorsal hairs can be characterized as medium plumbeous gray tipped with bright buff; the overall effect, however, is not so dark and somber a brown as in examples of H. anselli and H. arcimontensis (Fig. 5), but rather an even toned, dull yellowish brown (buckthorn brown), light to moderate in saturation. Guard hairs are brown with hyaline tips, only a little longer than the dorsal fur except over the rump. There is little tendency toward darker over the middle dorsum or conspicuously brighter flanks as is common in the other two species; color is generally evenly graded in expression over the entire dorsum, from the middle back to the flanks. A few individuals of H. heinrichorum exhibit brighter ochraceous-tipped hairs along the upper leg and shoulder and side of the head; nevertheless, the dorsal pelage color is predominantly even toned in appearance. Dorsal-ventral pelage contrast is well marked but not accentuated by a brighter lateral line. In all three species, the ventral hairs are basally gray and tipped with white, imparting a grayish-white effect. The three can be crudely sorted as bright gray (H. arcimontensis), medium gray (H. heinrichorum), and dark gray (H. anselli), with much variation and overlap among them. The tail of H. heinrichorum, as in other members of the H. anselli group, is notably longer than the head and body (TL ≈ 142–146 % of HBL), its color dusky-brown and wholly dark around the circumference; caudal scales are finely textured and hairs short, imparting a naked appearance over most of its length, the fine caudal hairs becoming macroscopically visible toward the tip. The hind foot is short and narrow, as per the genus, with digit 5 nearly as long as digits 2–4; the naked plantar surface bears six well-formed, cushiony pads. Pale brown hairs of the limb usually continue onto the ankle and proximal metatarsum, forming a dusky medial metatarsal streak in some individuals, replaced by white hairs over the distal metatarsum and phalanges; glistening white ungual tufts are present. Pinnae are pale brown to dark tan in the Angolan species, compared with darker, more blackish brown ears in the other two. As a gestalt observation, the skull of H. heinrichorum is approximately equal to or only slightly smaller than H. anselli, albeit heavier in build, but both are substantially larger than H. arcimontensis (Figs. 6, 7). Thus, standard external measurements and those we recorded for the skull and molar rows easily serve to distinguish examples of H. heinrichorum from those of the smaller H. arcimontensis and H. kerbispeterhansi (Table 6); size routinely emerged as the preeminent factor accounting for their separation in multivariate space (Figs. 1, 3). Mensural differences between H. heinrichorum and H. anselli, on the other hand, are not readily grasped when eyeballing series of skulls, yet specimens of each did conform to distinct morphometric footprints based on the cranial measurements we obtained (see Figs. 1, 2 C). However, fewer variables contributed to their discrimination, rendering their cranial separation correspondingly more difficult, based on subtle distinctions. Configuration of the hard palate relative to the length of the incisive foramina offers particularly important contrasts, those variables (BBP, HPL, LIF) loading strongly on that principal component which captured their separation in multivariate space (Fig. 2 C, Table 4). As practical anatomical landmarks when viewing skulls, these loadings translate as absolutely shorter incisive foramina (LIF ca. 69–73 % of LD) whose posterior end falls just short of or about level with the anterior border of the M 1 anterior root in H. anselli, versus longer incisive foramina (LIF ca. 75–80 % of LD) that extend beyond the anterior roots about to the rim of the first lamina of M 1 in H. heinrichorum. Therefore, the incisive foramina in H. heinrichorum are proportionately the longest within the H. anselli group, albeit not so “long” as members of the H. denniae group. The absolutely longer bony palate documented in H. anselli, compared with a shorter palate in H. heinrichorum, is a reciprocal geometric corollary of the different foraminal lengths (Table 6). The shape of the incisive foramina, however, is similar in both: broader over the anterior portion, narrowing slightly over the posterior half. The dorsal notch formed between the upper zygomatic plate and rostrum appears slightly deeper and wider in specimens of H. heinrichorum compared with crania of H. anselli and H. arcimontensis (Fig. 6), a visual impression consistent with the actually broader zygomatic plate recorded in the former (Table 6) and the important contribution of this variable (BZP) to between-group discrimination (Table 4). The interorbital region of H. heinrichorum conforms to that described for the H. anselli group: relatively narrow and amphoral in shape over its anterior portion, with post-orbital shelving weakly expressed in full and old adults, its edges lacking supraorbital ridging or beading. When examining series of skulls arrayed side-by-side (Figs. 6, 7), examples of H. anselli exhibit the longest, more attenuate rostrum, those of H. arcimontensis the shortest and most truncate, and those of H. heinrichorum appear intermediate in rostral length and shape. These macroscopic impressions find some statistical precision in the sample statistics (Table 6), variable loadings of the ordinations performed (Tables 1, 2, 5), and/or one-way ANOVAs (Table 4). Specimens of H. heinrichorum dentally resemble those of H. anselli and H. arcimontensis in the slight curvature of the upper incisors (nearly orthodont or weakly opisthodont), molar proportions, and cusp development. Pigmentation of the enamel face of the upper incisors in H. heinrichorum is a more saturated, medium orange compared with pale yellow-orange in H. anselli and H. arcimontensis; the tone is drab in all three. Ecological notes. Other species of the Hylomyscus anselli group are known to be closely associated with Afromontane forest, typically found within an elevational belt of 1000–2500 m (Carleton & Stanley, 2005; Carleton et al., 2006; Demos et al., 2014 b). The habitat information recorded on the skin tag of all Hylomyscus specimens collected at Mt Moco—“Evergreen wood. – High mountain region”—fits this ecological and topographical setting. Also, a photograph, taken by some member of Heinrich’s field team and labeled only Mt Moco, captures a substantial stand of closed-canopy, high forest in the vicinity of a campsite that we believe to represent Heinrich’s “High mountain” collecting locality (Fig. 8). Mills et al. (2011) documented the condition of Afromontane forest on Mt Moco as part of their ongoing studies of the endangered Swierstra’s Francolin (Francolinus swierstrai Roberts), a partridge-like bird endemic to Angola. High forest persists as small patches, the largest about 25 hectares, restricted to narrow ravines and steep valleys in the remotest parts of the mountain; these isolated fragments are distributed over an elevation of 2000 to 2400 m, a range that falls within the 1400 mm annual rainfall isohyet. Characteristic genera include the Gondwanan conifer Podocarpus along with other evergreen, flowering trees and shrubs (species of Apodytes, Ficus, Halleria, Ilex, Olea, Pittosporum, Polyscias, and Syzygium — Huntley & Matos, 1994; Mills et al., 2011). Canopy height tends to be irregular, conforming to the steep slopes and rugged valleys that retain forest coverage. Montane grasslands, both natural and anthropogenic, and Miombo woodlands, dominated by Brachystegia, Isoberlinia, and Julbernardia, sprawl in between the high-forest patches; the latter woodlands, a relatively mesic savanna association (Zambezian Woodland Biotic Zone), cover most of the mountain. Presumably, tracts of Afromontane forest were more extensive when Heinrich visited Mt Moco in 1954. Most skin tags of H. heinrichorum from Mt Soque indicate their capture “Along mountain brook through tall grass. – Below mt. top.” Whether remnant Afromontane forest existed in proximity to Heinrich’s trap line is indeterminate from this scant description. When Mills canvassed Mt Soque for Swierstra’s Francolin in 2005, he (Mills et al., 2011: 6) recorded that Afromontane forest no longer existed, but a few pairs of the endangered francolin were discovered in “dense herbaceous and shrubby growth in gullies and around the mountain summit [peak at 2165 m].” Other rodents collected with Hylomyscus heinrichorum over the same range of dates at both Mt Soque (24–28 Aug 1954) and Mt Moco (5–10 Oct 1954) include Funisciurus congicus Kuhl, Graphiurus murinus Desmarest, Dendromus nyikae Wroughton, Grammomys dolichurus Smuts, Lophuromys angolensis Verheyen, Dierckx, & Huselmans, Myomyscus angolensis Bocage, Oenomys hypoxanthus Pucheran, and Pelomys campanae Huet. Examples of Aethomys namaquensis A. Smith, Graphiurus rupicola Thomas & Hinton, Mus triton Thomas, Otomys cuanzensis Hill & Carter, and Cryptomys mechowi Peters were captured in sympatry with H. heinrichorum only at Mt Soque, but not Mt Moco; specimens of Mus minutoides Smith, Cryptomys hottentotus Lesson, and Thryonomys gregorianus Thomas were also obtained at Mt Moco, but not at Mt Soque. Certain species in some of these genera have been documented in moist forest at high elevations (e.g., Graphiurus, Dendromus, Grammomys, Lophuromys — Stanley et al., 1998); still more of them are commonly associated with non-forest habitatsgrasslands, open woodlands, marshes and riverine vegetation, thickets and forest edges—environments that are also represented on Mt Moco and were around Heinrich’s campsite at the time of their survey (Fig. 8). At this stage of understanding, Hylomyscus heinrichorum may be reasonably characterized as endemic to Afromontane forest based on the habitat recorded for the Mt Moco series and on the known affinity of its speciesgroup relatives for highland forest. However, without knowing the exact placement of Heinrich’s trap line and traps, its strict ecological reliance upon this biome must remain inferential pending renewed field surveys. Fresh autecological study is obviously in order. Remarks. To our knowledge, specimens of Hylomyscus heinrichorum have not been collected since the 1954 Heinrich expedition. Until new field assessments are conducted, the conservation status of H. heinrichorum is plausibly considered Near Threatened, if not Vulnerable, in view of the continuing decline in extent and quality of Afromontane forest in Angola (Huntley & Matos, 1994; Mills et al., 2011). Unlike the Endangered classification of Swiestra’s Francolin (IUCN Red List, accessed Jul 2014), a comestible, partridge-sized bird subjected to hunting pressure compounded by disappearance of its preferred habitat, populations of a small murid rodent like H. heinrichorum should remain resilient to habitat loss so long as even minimal forest cover, primary or secondary, persists. The recent documentation of substantial tracts of Afromontane forest in the Namba Mts (Mills et al., 2013), situated in southern Cuanza Sul Province about 80 km northwest of Mt Moco, augurs that ample populations of H. heinrichorum still exist. Etymology. Our specific epithet honors both Gerd Hermann Heinrich (1896–1984) and Hildegarde Maria Buruvna (1917–2012), husband and wife (Fig. 9), to belatedly acknowledge their important field work in Africa conducted in the middle 1900 s. Notwithstanding the enduring scientific relevance of their bird and mammal collections, these museum expeditions—to Angola (1953 –1955, 1957– 1958), Tanzania (1961–1963), and South Africa (1963)—unfolded as a means to an end, that end being to afford Heinrich yet another opportunity to pursue his zoological first love, the natural history and taxonomic diversity of parasitic wasps or ichneumon flies (Insecta: Hymenoptera: Ichneumonidae). While just a teenager, Heinrich devoted himself to understanding this exceedingly diverse, systematically intractable family, and it remained a lifelong passion, somehow sustained during, between, and after the World Wars that sundered normalcy in Europe. He opportunistically promoted his service as professional collector, obtaining vertebrate specimens under the auspices of large, well funded museums in order to vi, Published as part of Carleton, Michael D., Banasiak, Rebecca A. & Stanley, William T., 2015, A new species of the rodent genus Hylomyscus from Angola, with a distributional summary of the H. anselli species group (Muridae: Murinae: Praomyini), pp. 101-128 in Zootaxa 4040 (2) on pages 111-119, DOI: 10.11646/zootaxa.4040.2.1, http://zenodo.org/record/235102, {"references":["Crawford-Cabral, J. (1998) The Angolan rodents of the Superfamily Muroidea: An account of their distribution. Insituto de Investigacao Ceintifica Tropical, Lisboa (Estudos, Ensaios e Documentos, 161, 1 - 222.","Crawford-Cabral, J. (1986) A discussion of the taxa to be used in a zoogeographical analysis as illustrated in Angolan Muroidea. Cimbebasia, Serie A, 8 (19), 161 - 166.","Musser, G. G. & Carleton, M. D. (1993) Family Muridae. In: Wilson, D. E. & Reeder, D. M. (Eds.), Mammal species of the world: A taxonomic and geographic reference, Second Edition. Smithsonian Institution Press, Washington, D. C., pp. 501 - 755.","Dieterlen, F. (2013) Hylomyscus denniae Montane Wood Mouse (Montane Hylomyscus). In: Happold, D. C. D. (Ed.), Mammals of Africa. Vol. III. Rodents, Hares and Rabbits. Bloomsbury Publishing, London, pp. 434 - 436.","Carleton, M. D. & Stanley, W. T. (2005) Review of the Hylomyscus denniae complex in Tanzania, with description of a new species. Proceedings of the Biological Society of Washington, 118, 619 - 646.","Carleton, M. D., Kerbis Peterhans, J. & Stanley, W. T. (2006) Review of the Hylomyscus denniae group (Rodentia: Muridae) in eastern Africa, with comments on the generic allocation of Epimys endorobae Heller. Proceedings of the Biological Society of Washington, 119, 293 - 325. http: // dx. doi. org / 10.2988 / 0006 - 324 X (2006) 119 [293: ROTHDG] 2.0. CO; 2","Demos, T. C., Agwanda, B. & Hickerson, M. J. (2014 b) Integrative taxonomy within the Hylomyscus denniae complex (Rodentia: Muridae) and a new species from Kenya. Journal of Mammalogy, 95 (1), E 1 - E 15. http: // dx. doi. org / 10.1644 / 13 - MAMM-A- 268","Mills, M. S. L., Olmos, F., Melo, M. & Dean, W. R. J. (2011) Mount Moco: its importance to the conservation of Swierstra's Francolin Pternistis swierstrai and the Afromontane avifauna of Angola. Bird Conversation International, 21, 119 - 133. http: // dx. doi. org / 10.1017 / S 0959270910000493","Huntley, B. J. & Matos, E. M. (1994) Botantical diversity and its conservation in Angola. Stelitzia, 7, 53 - 74.","Stanley, W. T., Kihaule, P. M., Howell, K. M. & Hutterer, R. (1998) Small mammals of the Eastern Arc Mountains, Tanzania. Journal of East African Natural History, 87, 91 - 100.","Mills, M. S. L., Melo, M. & Vaz, A. (2013) The Namba mountains: new hope for Afromontane forest birds in Angola. Bird Conservation International, 23, 159 - 167. http: // dx. doi. org / 10.1017 / S 095927091200024 X","Heinrich, G. (1934) Die Ichneumoninae von Celebes bearbeitet auf Grund der Ausbeute der Celebes Expedition G. Heinrich 1930 - 1932. Mitteilungen aus dem Zoologischen Museum in Berlin, 20, 1 - 263.","Heinrich, G. (1938) Les Ichneumonides de Madagascar. III. Ichneumonidae, Ichneumoninae. Memoires de l'Academie Malgache, 25, 1 - 139.","Heinrich, G. (1961 - 1962) Synopsis of Nearctic Ichneumoninae Stenopneusticae with particular reference to the Northeastern Region (Hymenoptera). Canadian Entomologist. Supplement, 886 pp. [in 8 parts]","Weems, H. V. Jr. (1986) In memoriam Gerd H. Heinrich. Florida Entomologist, 69 (1), 281 - 282.","Heinrich, B. (2007) The snoring bird: my family's journey through a century of biology. Harper Collins Publishers, New York, xvii + 461 pp.","Collar, N. J. (2009) Pioneer of Asian ornithology: Gerd Heinrich. Birding Asia, 11, 33 - 40.","Tate, G. H. H. (1954) A new squirrel from Burma. American Museum Novitates, 1676, 1 - 2."]}

Otomys simiensis new species Figs. 2c, 5, 6, 17; Table 9 Simien Vlei Rat Holotype. ZMMU 178757; adult male, dry skin and skull, collector’s number 1338; collected by L.A. Lavrenchenko, 4 May 2005. Type locality. Ethiopia, Simien Mountains National Park, vicinity of Sankaber campsite, 3250 m; 13°14'N, 38°03'E (GPS reading by collector). Diagnosis. A small-sized representative of the O. typus species complex (referred to “Sp. D” above; see Figs. 5, 6, 17 and Tables 7, 9). Similar to O. yaldeni but considerably larger externally (HB mean 155 mm in simiensis, cf. 143 in yaldeni; tail means 83 mm and 72 mm respectively); skull having a narrower interorbital region, less pronounced supraorbital ridges, relatively longer nasal bones, and braincase with flatter dorsal profile (Fig. 17); karyotype distinctive (2N=54, NF=56). Paratypes. ZMMU 178756 (adult female, dry skin and skull, collector’s number 1336); ZMMU 178758 (adult male, dry skin and skull, collector’s number 1352); ZMMU 178759 (adult male, dry skin and skull, collector’s number 1353); ZMMU 178762 (adult female, dry skin and skull, collector’s number 1429); all four specimens from the type locality, collected by L.A. Lavrenchenko between 4 and 20 May 2005. Description. The dorsal pelage is dark brown, with individual hairs having a blackish base, rufous subterminal band, and relatively narrow black tip. Among the guard hairs (17 mm), there are longer bristles (26 mm) that produce the effect of the double-layered fur. Ventral pelage is pale grey, the individual hairs grey at the base and tipped with pale whitish. The ears are blackish, their inner surface covered with short rufous hairs. Dorsal surfaces of the forefeet and hindfeet are dark grey, and the claws are grey. The tail is moderately long (53.4% of HB) and appears distinctly bicoloured, the dorsal caudal hairs relatively long and blackish in contrast to the white ventral hairs. The skull resembles most other members of the O. typus complex, having a relatively narrow interorbital region, reduced supraorbital ridges, shallow braincase, and short anterior palatal foramen (Table 9). Anterior face of the lower incisor has two well defined and equally deep grooves. The upper third molar possesses 7 complete laminae; the lower first molar possesses 4 complete laminae. The chromosomal complement of O. simiensis consists of 2N=54, NF=56; 2m + 52a (Fig. 2c). Otomys simiensis differs from other Ethiopian Otomys (excluding yaldeni) by the lower number of laminae in the upper third molar (7 versus 8–9) and the double-layered dorsal fur. Amongst other members of typus s.l., simiensis is most like jacksoni which is similar in skull size and shape (Table 9) and also has 7 laminae in the third upper molar and a similar dark brown colour (Bohmann 1952); however, jacksoni is much smaller in external dimensions (HB mean 141 mm in jacksoni cf. 155 mm in simiensis) and has a proportionately shorter tail (45.4% in jacksoni cf. 53.4% in simiensis). Furthermore molecular data (Fig. 3) clearly demonstrate the genetic separation of these taxa. Distribution. Known only from the type locality in the Simien Mountains, northern Ethiopia (see above). Ecology. The holotype and paratypes of O. simiensis were captured in tree-heather forest (trees: Erica arborea, Hypericum revolutum; shrub: Rosa abyssinica) with open grassy patches. At higher altitudes, this species is replaced by O. typus s.s., a common inhabitant of the afroalpine zone in the Simien Mountains National Park (e.g., Chennek area, 13°15’N, 38°13’E, 3800 m). Etymology. The rugged Simien Mountains, to which the new species is apparently endemic, dominate the northern plateau of Ethiopia and contain its highest peaks. The name combines the stem Simien with the Latin suffix “ensis,” meaning “native of” or “characteristic of” the place indicated by the stem.

Taylor, Peter J., Lavrenchenko, Leonid A., Carleton, Michael D., Verheyen, Erik, Bennett, Nigel C., Oosthuizen, Carel J., Maree, Sarita (2011): Specific limits and emerging diversity patterns in East African populations of laminate-toothed rats, genus Otomys (Muridae: Murinae: Otomyini): Revision of the Otomys typus complex 3024. Zootaxa 3024 (1): 1-66, DOI: 10.11646/zootaxa.3024.1.1, URL: https://biotaxa.org/Zootaxa/article/view/zootaxa.3024.1.1

Otomys thomasi Osgood, 1910 Otomys thomasi; Osgood, 1910:9 (type locality—British East Africa [Kenya], Molo; holotype — FMNH 16698). Otomys thomasi thomasi; Dollman, 1915:153 (taxonomic revision, retained as species, de facto arrangement as nominate subspecies); Hollister, 1919:147 (faunal report, listed as valid species and subspecies); Allen, 1939:346 (listed as valid species and subspecies); Ellerman, 1941:323 (listed as valid species and subspecies). Otomys typus thomasi; Bohmann, 1952:41 (taxonomic revision, new name combination, retained as valid subspecies). Otomys typus [thomasi]; Misonne, 1974:33 (listed in synonymy without indication of rank); Musser & Carleton, 1993:682 (listed in synonymy without indication of rank). Otomys orestes [thomasi]; Musser & Carleton, 2005:1529 (new name combination, listed in synonymy without indication of rank); Carleton & Byrne, 2006:497 (taxonomic revision, retention of thomasi as junior synonym). Distribution. High plateau and mountains that form the western border of the Rift Valley (eastern branch), central Kenya; elevational range ca. 2450–2750 m. Specimens examined. KENYA: Uasin Gishu Plateau, 32 km N Eldama Ravine, 9,000 ft (2743 m) (USNM 164290); Molo (FMNH 16693–16695, 16698, 16699)., Published as part of Taylor, Peter J., Lavrenchenko, Leonid A., Carleton, Michael D., Verheyen, Erik, Bennett, Nigel C., Oosthuizen, Carel J. & Maree, Sarita, 2011, Specific limits and emerging diversity patterns in East African populations of laminate-toothed rats, genus Otomys (Muridae: Murinae: Otomyini): Revision of the Otomys typus complex 3024, pp. 1-66 in Zootaxa 3024 (1) on pages 47-48, DOI: 10.11646/zootaxa.3024.1.1, http://zenodo.org/record/5280584, {"references":["Osgood, W. H. (1910) Diagnoses of new East African mammals, including a new genus of Muridae. Field Museum of Natural History, Zoological Series, 10, 5 - 13.","Dollman, G. (1915) On the swamp-rats (Otomys) of East Africa. Annals and Magazine of Natural History, series 8 15, 149 - 170.","Allen, G. M. (1939) A checklist of African mammals. Bulletin of the Museum of Comparative Zoology at Harvard College, 83, 1 - 763.","Ellerman, J. R. (1941) The families and genera of living rodents. Volume II. Family Muridae. British Museum (Natural History), London. 690 pp.","Bohmann, L. (1952) Die afrikanische Nagergattung Otomys F. Cuvier. Zeitschrift fur Saugetierkunde, 18, 1 - 80.","Misonne, X. (1974) Part 6, Order Rodentia. In: Meester, J. & Setzer, H. W. (Eds.), The mammals of Africa: an identification manual. Smithsonian Institution Press, Washington, D. C.","Musser, G. G. & Carleton, M. D. (1993) Family Muridae. In: Wilson, D. E. & Reeder, D. M. (Eds.), Mammal Species of the World: a taxonomic and geographic reference 2 nd edition. Smithsonian Institution Press, Washington D. C., 501 - 755.","Musser, G. G. & Carleton, M. D. (2005) Superfamily Muroidea. In: Wilson, D. E. & Reeder, D. M. (Eds.), Mammal species of the world: a taxonomic and geographic reference 3 rd edition. John Hopkins University Press, Baltimore, 894 - 1531.","Carleton, M. D. & Byrne, E. S. (2006) The status of Otomys orestes dollmani Heller, 1912 (Muridae: Otomyinae), a rodent described from the Mathews Range, central Kenya. Proceedings of the Biological Society of Washington, 119, 477 - 515."]}

Otomys zinki Bohmann, 1943 Otomys typus zinki; Bohmann, 1943:153 (type locality— German East Africa [Tanzania], Kilimanjaro, Peters Hut, 3800 m; holotype —not seen; listed as “No. 548” in his private collection by Bohmann, 1943); Swynnerton and Hayman, 1951:321 (faunal report, listed as valid subspecies); Bohmann, 1952:41 (taxonomic revision, retained as valid subspecies). Otomys typus [zinki]; Misonne, 1974:33 (listed in synonymy without indication of rank); Musser & Carleton, 1993:682 (listed in synonymy without indication of rank). Otomys orestes [zinki]; Musser & Carleton, 2005:1528 (new name combination, listed in synonymy without indication of rank). Distribution. The species is limited in its distribution to Mt Kilimanjaro. Specimens examined. TANZANIA: Kilimanjaro (SM 4270, 4272, 4278, 4280); Mount Kilimanjaro East, Maundi Crater, grassland, 3270 m (RMCA 96.037.M-6801, 96.037.M-6802, 96.037.M-6803, 96.037.M-6804, 96.037.M-6805, 96.037.M-6801); Mount Kilimanjaro West, Londorosi, forest, 2350 m (96.037.M-6807, 96.037.M-6810); Mount Kilimanjaro West, Shira, moorland, 3000 m (96.037.M-6809); Mount Kilimanjaro, Kilimanjaro National Park, 13,100 ft (3993 m) (FMNH 174178–174180); Mount Kilimanjaro, Kilimanjaro National Park, 7 km N and 2.5 km W Maua, 8,100 ft (2469 m) (FMNH 174173, 174174)., Published as part of Taylor, Peter J., Lavrenchenko, Leonid A., Carleton, Michael D., Verheyen, Erik, Bennett, Nigel C., Oosthuizen, Carel J. & Maree, Sarita, 2011, Specific limits and emerging diversity patterns in East African populations of laminate-toothed rats, genus Otomys (Muridae: Murinae: Otomyini): Revision of the Otomys typus complex 3024, pp. 1-66 in Zootaxa 3024 (1) on page 53, DOI: 10.11646/zootaxa.3024.1.1, http://zenodo.org/record/5280584, {"references":["Bohmann, L. (1943) Zwei neue Otomys-Rassen aus Ostafrika. Zoologischer Anzeiger, 143, 153 - 155.","Bohmann, L. (1952) Die afrikanische Nagergattung Otomys F. Cuvier. Zeitschrift fur Saugetierkunde, 18, 1 - 80.","Misonne, X. (1974) Part 6, Order Rodentia. In: Meester, J. & Setzer, H. W. (Eds.), The mammals of Africa: an identification manual. Smithsonian Institution Press, Washington, D. C.","Musser, G. G. & Carleton, M. D. (1993) Family Muridae. In: Wilson, D. E. & Reeder, D. M. (Eds.), Mammal Species of the World: a taxonomic and geographic reference 2 nd edition. Smithsonian Institution Press, Washington D. C., 501 - 755.","Musser, G. G. & Carleton, M. D. (2005) Superfamily Muroidea. In: Wilson, D. E. & Reeder, D. M. (Eds.), Mammal species of the world: a taxonomic and geographic reference 3 rd edition. John Hopkins University Press, Baltimore, 894 - 1531."]}

Otomys uzungwensis Lawrence and Loveridge, 1953 Otomys percivali; Allen & Loveridge, 1933:119 (faunal report, preliminary identification); Swynnerton and Hayman, 1951:322 (faunal work, listed as species per Allen & Loveridge, 1933). Otomys uzungwensis; Lawrence & Loveridge, 1953:61 (type locality— Tanganyika Territory [Tanzania], Iringa District, Uzungwe Mountains, Dabaga; holotype — MCZ 26645); Musser & Carleton, 2005:1530 (reinstated as valid species); Carleton & Byrne, 2006:492 (taxonomic revision, retained as valid species). Otomys typus [uzungwensis]; Misonne, 1974:33 (new name combination, listed in synonymy without indication of rank); Musser & Carleton, 1993:682 (listed in synonymy without indication of rank). Otomys typus uzungwensis; Ansell, 1978:78 (faunal work, listed as valid subspecies); Ansell & Dowsett, 1988:102 (faunal work, listed as valid subspecies). Distribution. Udzungwa Mountains in westcentral Tanzania to the Nyika Plateau, northern Malawi and contiguous Zambia; elevational range ca. 1800–2750 m. Specimens examined. MALAWI: Nyika Plateau, Chelinda (BMNH 62.337, 66.1094, 78.2722); Nyika Plateau, 7,000 ft (2133.6 m) (MCZ 43947, 43950); (FMNH 192029, 192030). TANZANIA: Udzungwe Mountains, Kigoro (MCZ 26637, 26638, 26640–26644); Udzungwe Mountains, Iringa District, Dabaga, 6,000 ft (1828.8 m) (MCZ 26645, 26646, 26648–26653, 26655, 26656, 26664); Poroto Mountains, Mbeya, 9,000 ft (2743.2 m) (MCZ 51147)., Published as part of Taylor, Peter J., Lavrenchenko, Leonid A., Carleton, Michael D., Verheyen, Erik, Bennett, Nigel C., Oosthuizen, Carel J. & Maree, Sarita, 2011, Specific limits and emerging diversity patterns in East African populations of laminate-toothed rats, genus Otomys (Muridae: Murinae: Otomyini): Revision of the Otomys typus complex 3024, pp. 1-66 in Zootaxa 3024 (1) on pages 48-52, DOI: 10.11646/zootaxa.3024.1.1, http://zenodo.org/record/5280584, {"references":["Lawrence, B. & Loveridge, A. (1953) Zoological results of a fifth expedition to East Africa. I. Mammals from Nyasaland and Tete. With notes on the genus Otomys. Bulletin of the Museum of Comparative Zoology at Harvard College, 110, 1 - 80.","Allen, G. M. & Loveridge, A. (1933) Reports on the scientific results of an expedition to the southwestern highlands of Tanganyika Territory. II. Mammals. Bulletin of the Museum of Comparative Zoology at Harvard College, 75, 47 - 140.","Musser, G. G. & Carleton, M. D. (2005) Superfamily Muroidea. In: Wilson, D. E. & Reeder, D. M. (Eds.), Mammal species of the world: a taxonomic and geographic reference 3 rd edition. John Hopkins University Press, Baltimore, 894 - 1531.","Carleton, M. D. & Byrne, E. S. (2006) The status of Otomys orestes dollmani Heller, 1912 (Muridae: Otomyinae), a rodent described from the Mathews Range, central Kenya. Proceedings of the Biological Society of Washington, 119, 477 - 515.","Misonne, X. (1974) Part 6, Order Rodentia. In: Meester, J. & Setzer, H. W. (Eds.), The mammals of Africa: an identification manual. Smithsonian Institution Press, Washington, D. C.","Musser, G. G. & Carleton, M. D. (1993) Family Muridae. In: Wilson, D. E. & Reeder, D. M. (Eds.), Mammal Species of the World: a taxonomic and geographic reference 2 nd edition. Smithsonian Institution Press, Washington D. C., 501 - 755.","Ansell, W. F. H. (1978) The mammals of Zambia. Chilanga, Zambia, The National Parks and Wildlife Service, 126 pp.","Ansell, W. F. H. & Dowsett, R. J. (1988) Mammals of Malawi: An annotated checklist and atlas. Cornwall, The Trendrine Press, 170 pp."]}

Otomys fortior Thomas, 1906a Otomys typus fortior; Thomas, 1906a:302 (type locality— Ethiopia, Kaffa, Charada Forest, 6000 ft [1829 m]; holotype — BMNH 6.11.1.29); Allen, 1939:348 (listed as valid subspecies); Ellerman, 1941:321 (listed as valid subspecies); Bohmann, 1952:45 (taxonomic revision, retained as valid subspecies). Otomys fortior; Dollman, 1915:170 (taxonomic revision, elevation to species). Otomys typus [fortior]; Misonne, 1974:33 (listed in synonymy without indication of rank); Yalden et al., 1976:56 (faunal work, listed in synonymy without indication of rank); Musser & Carleton, 1993:682, 2005:1530 (listed in synonymy without indication of rank). Distribution. Restricted to montane evergreen forests in the southwestern regions of Ethiopia (see OTU 2 in Fig. 1a). Although specimens from Jimma are assigned provisionally to O. fortior based on geographic and ecological proximity, we note that morphometrically this series is characterized by large cranial size making them comparable with specimens from “Sp. C” from the Lake Tana region of central Ethiopia. Specimens examined. ETHIOPIA: Kaffa, Charada Forest, 6,000 ft (1828.8 m) (BMNH 6.11.1.29); Beletta Forest (ZMMU 164960–164965, 166072); Sheko Forest (ZMMU 167310); Oromiya, Jimma, 1750 m (USNM 515058–515064, 516317, 516507); Inegawa Forest, 20 km N of Tepi, 2340 m (ZMMU 181665–181667)., Published as part of Taylor, Peter J., Lavrenchenko, Leonid A., Carleton, Michael D., Verheyen, Erik, Bennett, Nigel C., Oosthuizen, Carel J. & Maree, Sarita, 2011, Specific limits and emerging diversity patterns in East African populations of laminate-toothed rats, genus Otomys (Muridae: Murinae: Otomyini): Revision of the Otomys typus complex 3024, pp. 1-66 in Zootaxa 3024 (1) on page 45, DOI: 10.11646/zootaxa.3024.1.1, http://zenodo.org/record/5280584, {"references":["Thomas, O. (1906 a) New mammals collected in north-east Africa by Mr. Zaphiro, and presented to the British Museum by W. N. McMillan. Annals and Magazine of Natural History, series 7, 18, 300 - 306.","Allen, G. M. (1939) A checklist of African mammals. Bulletin of the Museum of Comparative Zoology at Harvard College, 83, 1 - 763.","Ellerman, J. R. (1941) The families and genera of living rodents. Volume II. Family Muridae. British Museum (Natural History), London. 690 pp.","Bohmann, L. (1952) Die afrikanische Nagergattung Otomys F. Cuvier. Zeitschrift fur Saugetierkunde, 18, 1 - 80.","Dollman, G. (1915) On the swamp-rats (Otomys) of East Africa. Annals and Magazine of Natural History, series 8 15, 149 - 170.","Misonne, X. (1974) Part 6, Order Rodentia. In: Meester, J. & Setzer, H. W. (Eds.), The mammals of Africa: an identification manual. Smithsonian Institution Press, Washington, D. C.","Yalden, D. W., Largen, M. J. & Kock, D. (1976) Catalogue of the mammals of Ethiopia. 2. Insectivora and Rodentia. Monitore Zoologico Italiano, Supplemento 8 (1), 1 - 118.","Musser, G. G. & Carleton, M. D. (1993) Family Muridae. In: Wilson, D. E. & Reeder, D. M. (Eds.), Mammal Species of the World: a taxonomic and geographic reference 2 nd edition. Smithsonian Institution Press, Washington D. C., 501 - 755.","Musser, G. G. & Carleton, M. D. (2005) Superfamily Muroidea. In: Wilson, D. E. & Reeder, D. M. (Eds.), Mammal species of the world: a taxonomic and geographic reference 3 rd edition. John Hopkins University Press, Baltimore, 894 - 1531."]}

Otomys dartmouthi Thomas, 1906b Otomys dartmouthi; Thomas, 1906b:141 (type locality— Uganda, Ruwenzori East, Mubuku Valley, 12,500 ft [3810 m]; holotype —BMNH 6.7.1.64); Dollman, 1915:166 (taxonomic revision, retained as species); Allen, 1939:344 (listed as valid species); Ellerman, 1941:322 (listed as valid species); Musser & Carleton, 2005:1526 (reinstated as valid species). Otomys typus dartmouthi; Bohmann, 1952:43 (taxonomic revision, new name combination, retention as valid subspecies). Otomys typus [dartmouthi]; Misonne, 1974:33 (listed in synonymy without indication of rank); Musser & Carleton, 1993:682 (listed in synonymy without indication of rank). Otomys irroratus [dartmouthi]; Delany, 1975:53 (faunal work, new name combination, listed in synonymy without indication of rank). Distribution. Alpine habitats, ca. 3300–4400 m, of the Ruwenzori Mountains, southwestern Uganda and contiguous eastern D.R. Congo. Specimens examined. D. R. CONGO: Blanc (RMCA 1095); Kalindera Masereka (RMCA 82011 -M827); Virungas, Albert National Park, Wusuwameso, 4380 m (RMCA 82011 -M830, 82011-M831). UGANDA: Ruwenzori East, Mubuku Valley, 12,500 ft (3810 m) (BMNH 6.7.1.62–6.7.1.65); Kasese District, Ruwenzoris, left bank Bujuku River, 11,050 ft (3368.04 m) (FMNH 144327, 144328, 144330); Kasese District, Ruwenzoris, above Lake Bujuku, 13,050 ft (3977.64 m) (FMNH 144334–144336, 144338, 144341, 144342)., Published as part of Taylor, Peter J., Lavrenchenko, Leonid A., Carleton, Michael D., Verheyen, Erik, Bennett, Nigel C., Oosthuizen, Carel J. & Maree, Sarita, 2011, Specific limits and emerging diversity patterns in East African populations of laminate-toothed rats, genus Otomys (Muridae: Murinae: Otomyini): Revision of the Otomys typus complex 3024, pp. 1-66 in Zootaxa 3024 (1) on page 44, DOI: 10.11646/zootaxa.3024.1.1, http://zenodo.org/record/5280584, {"references":["Thomas, O. (1906 b) Descriptions of new mammals from Mount Ruwenzori. Proceedings of the Zoological Society, London, 1906, 136 - 147.","Dollman, G. (1915) On the swamp-rats (Otomys) of East Africa. Annals and Magazine of Natural History, series 8 15, 149 - 170.","Allen, G. M. (1939) A checklist of African mammals. Bulletin of the Museum of Comparative Zoology at Harvard College, 83, 1 - 763.","Ellerman, J. R. (1941) The families and genera of living rodents. Volume II. Family Muridae. British Museum (Natural History), London. 690 pp.","Musser, G. G. & Carleton, M. D. (2005) Superfamily Muroidea. In: Wilson, D. E. & Reeder, D. M. (Eds.), Mammal species of the world: a taxonomic and geographic reference 3 rd edition. John Hopkins University Press, Baltimore, 894 - 1531.","Bohmann, L. (1952) Die afrikanische Nagergattung Otomys F. Cuvier. Zeitschrift fur Saugetierkunde, 18, 1 - 80.","Misonne, X. (1974) Part 6, Order Rodentia. In: Meester, J. & Setzer, H. W. (Eds.), The mammals of Africa: an identification manual. Smithsonian Institution Press, Washington, D. C.","Musser, G. G. & Carleton, M. D. (1993) Family Muridae. In: Wilson, D. E. & Reeder, D. M. (Eds.), Mammal Species of the World: a taxonomic and geographic reference 2 nd edition. Smithsonian Institution Press, Washington D. C., 501 - 755.","Delany, M. J. (1975) The rodents of Uganda. London, Trustees of the British Museum (Natural History), 165 pp."]}

Otomys cheesmani new species Figs 5, 6, 17; Table 9 Cheesman’s Vlei Rat Holotype. BMNH 1937.2.24.84; adult male, dry skin and skull, collector’s number 7400; collected by R. E. Cheesman, 20 October 1937. Type locality. Ethiopia, vicinity of Dangila, 66 km S Lake Tana, 2100 m; 11°16’N, 36°51’E. Diagnosis. The largest representative of the Otomys typus species complex, differing from all other members by its distinctly larger and more robust skull with short and broad nasal bones, broad, angular and thickened zygomatic arches, very well developed supraorbital and parietal ridges and relatively very narrow interorbital region (referred to “Sp. C” above; see Figs 5, 6, 17 and Tables 7, 9). Paratypes. BMNH 28.1.11.117 (adult female, dry skin and skull, collector’s number 6040), BMNH 28.1.11.174 (adult male; dry skin and skull, collector’s number 6078), BMNH 28.1.11.175 (subadult male, dry skin and skull), BMNH 28.1.11.176 (subadult male, dry skin and skull, collector’s number 6366), BMNH 28.1.11.177 (adult female; dry skin and skull, collector’s number 6040), BMNH 28.1.11.178 (adult female, dry skin and skull, collector’s number 6070), BMNH 28.1.11.179 (adult female, dry skin and skull, collector’s number 6165), BMNH 1937.2.24.82 (adult male, dry skin and skull, collector’s number 7383), BMNH 1937.2.24.83 (adult male, dry skin and skull, collector’s number 7387), BMNH 1937.2.24.85 (adult male, dry skin and skull, collector’s number 7404), BMNH 1937.2.24.86 (adult female, dry skin and skull)—all 11 from the type locality, collected by R.E. Cheesman between 1926 and 1937; BMNH 70.657 (Ethiopia, Gojam, Debra Marcos, 2500 m; 10°20’N, 37°46’E; collected by Great Abbai Expedition, 19 August 1968). Description. The dorsal pelage of O. cheesmani is bright brown with a reddish shade. Ventral pelage is pale yellowish-grey, the individual hairs yellow tipped and grey at the base. The ears are blackish, their inner surface covered with short rufous hairs. The dorsal surface of the forefeet and hindfeet is dark grey; the claws are grey. The tail is relatively short (49.3% of HB). The caudal hairs are blackish on the upper surface and pale yellowish on the lower surface; however, the tail does not appear distinctly bicoloured. The robust skull of O. cheesmani (Fig. 17) is reflected in the large means recorded for most cranial dimensions, which exceed those of all other representatives of the O. typus complex except for interorbital width (Table 9). Although the observed ranges of certain external and cranial variables overlap, four cranial variables do not overlap in size: GLS (43.3–48.2 mm versus 34.3–43.3 mm); MXTL (11.0–12.0 mm versus 8.1–10.5 mm); NAW (8.0–9.0 mm versus 5.8–8.0 mm); PL (23.6–26.2 mm versus 16.7–23.6 mm) (Table 9). The anterior face of the lower incisor has two well defined and equally deep grooves. The upper third molar has 8 or 9 complete laminae (9 in the holotype) and the lower first molar 4 complete laminae. Distribution. Known only from two localities in northwestern Ethiopia, 2100–2500 m (see above). Ecology. The type locality currently represents a true agricultural landscape, presumably much transformed from the time when Cheesman collected the series. The holotype and paratypes of O. cheesmani were supposedly collected in an intrazonal wetland habitat. The specimen from Debra Marcos (BMNH 70.657) was captured in low Acacia scrub. Otomys cheesmani occupies lower elevations (2100–2500 m) than other Ethiopian Otomys (excluding the rainforest dweller O. fortior). Nevertheless, habitat requirements of this new species remain unclear. Etymology. We selected the specific epithet to recognize Robert E. Cheesman (1878–1962), who collected the holotype and topotypic series of this distinctive species of Otomys. Cheesman was a British military and diplomatic officer in the Middle East, Arabian Peninsula, and nearby Africa, and like many other professionals of this era, he developed broad interests in the geography and natural history of the lands where he worked. During his service as Consul in North-West Abyssinia, Cheesman not only explored the source of the Blue Nile and surveyed its course from Lake Tana to the Sudan border (Lake Tana and the Blue Nile: An Abyssinian Quest by R. E. Cheesman, 1936; Macmillan: London, 400 pp.), but also found time to collect bird and mammal specimens for the British Museum. The species name combines the surname Cheesman and genitive singular case-ending “i” indicative of masculine gender.