Hylomyscus stanleyi, Kerbis Peterhans & Hutterer & Doty & Malekani & Moyer & Krásová & Bryja & Banasiak & Demos, 2020
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publication ID |
https://doi.org/10.20363/BZB-2020.69.1.055 |
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publication LSID |
lsid:zoobank.org:pub:1FD4D09C-D160-4159-A50D-20B6FBC7D9E9 |
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persistent identifier |
https://treatment.plazi.org/id/C54F87EA-FFB5-FFCB-60B1-F991FC3DFC47 |
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treatment provided by |
Felipe |
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scientific name |
Hylomyscus stanleyi |
| status |
sp. nov. |
Hylomyscus stanleyi sp. nov. Kerbis Peterhans, Hutter- er & Demos
urn:lsid:zoobank.org:act:4512E5DE-2139-46CB-B2F9-823C9C3B1BAD Hylomyscus anselli – Carleton & Stanley (2005); Carleton, Kerbis Peterhans & Stanley (2006); Demos, Agwanda & Hickerson (2014a); Carleton, Banasiak & Stanley (2015)
Hylomyscus cf. anselli – Nicolas et al. (2020)
Holotype. Field Museum of Natural History , Division of Mammals number FMNH 171362 About FMNH (field number WT Stanley 4968), collected by Cosmos, 03 August 2001 (originally listed as Hylomyscus sp. ). The specimen, consisting of a skin, skull and alcoholic carcass, is an adult pregnant female with first upper molar well worn (stage IV of Verheyen & Bracke 1966). Teats 2+4, large, embryos 4L, 1 R ( CR 14 ). The holotype was captured in a local snare baited with corn. The basisphenoid-occipital suture is fused. External measurements were made in the field: TL 256, HB 106, TV 154 , HF 21, EL 20, Wt 29.
Type Locality. Tanzania, Rukwa Region, Sumbawanga District, Mbizi Forest Reserve , 0.5 km N, 4 km E of Wipanga, elevation 2200 m, 7.8639° S, 31.6694° E GoogleMaps .
Paratypes (n = 32). Mbizi Forest Reserve , 0.5 km N, 4 km E of Wipanga, elevation 2200 m, 171357–171361, 171363–171367, 171517–171518 (6 m, 6 f), 7.8639° S, 31.6694° E GoogleMaps ; Mbizi Forest Reserve , 0.5 km S, 3 km E of Wipanga, 2300 m, 171342–171356, 171512–171516 (12 m, 8 f), 7.8639° S, 31.6694° E GoogleMaps .
Diagnosis. UTR> 3.97 mm, maxillo-palatal suture locat- ed at the rear third to the rear half of M 1 ( Fig. 8d View Fig ), rostrum elongate (LN/ONL= 37.33, LN>9.3; Fig. 12b View Fig , Table 4), very large posterior palatal foramen (ca. 0.7–0.9 mm) starting between M 1 and M 2 and extending into anterior half of M 2 ( Figs 8d View Fig , 12d View Fig ), very large sub-squamosal foramen (30–40% area of postglenoid foramen, Fig. 12f View Fig ), fronto-parietal suture shallow V-shaped, zygomatic plate only slightly sinuous in lateral view, incisive foramina fall either just short of the alveoli of M 1 or barely reaching alveoli of M 1 ( Figs 8d View Fig , 12d View Fig ). T1 of M1 deflected far posteriorly ( Fig. 7a View Fig ).
70 Julian C. Kerbis Peterhans et al.
Comparisons. One of the largest members of the H. anselli group with an upper molar crown length over 4.0, thereby needing comparison with only Hylomyscus heinrichorum and H. anselli . Compared to H. heinrichorum , H. stanleyi is typically orthodont vs. slightly opisthodont, see Carleton et al. 2015: fig. 7c (as H. stanleyi ) vs. fig. 7b, has longer nasals (mean of 10.1 vs. 9.2; Ibid. 6c as H. anselli vs. 6b) with a more narrow zygomatic plate (Ibid. fig. 6c as H. anselli vs. fig. 6b, mean of 2.3 vs. 2.6) and with incisive foramina that do not penetrate the upper tooth row or alveoli (Ibid. fig. 6c as H. anselli vs. 6b). Since the sample size of available H. anselli is small (n = 4), we expect these differences may become more ambiguous as older individuals and additional samples of H. anselli become available.
Description. Size large (mean HB = 102, mean mass = 27.5 g; Table 5). Tail 43% longer than HB. Tail unicolor with ca. 15 annulations per cm. Belly hairs ca. 9 mm, basal 6 mm slate grey, apical 3 mm white. Dorsal hairs ca. 11 mm, basal 6 mm slate grey, terminal 3 mm tipped with light brown. Dorsum of head same color as dorsum of body. Upper lip with whitish hairs but with grey roots. Ears with blackish skin, hairs barely visible. Vibrissae long, up to 35 mm, black in color. Pes dirty white in appearance due to white hairs overlaying darker skin. Manus white. The hind foot possesses the standard
Four new Hylomyscus ( Muridae ) from Africa 71 murine complement of 6 pads (see Ibe et al. 2014: fig. 2. II for reference); there is a single accessory pad on each of the 1 st, 2nd and 4 th interdigital pads; the first is larger and well-integrated into the 1 st interdigital pad, the 2 nd is small but distinct from the 2 nd interdigital pad, while the 4 th is smaller but distinctly separate from the 4 th interdigital pad ( Fig. 9c View Fig ). There are seven fleshy palatal ridges: two are continuous and pre-dental, one is discontinuous and pre-dental, and the last four are discontinuous and inter-dental ( Fig. 13 View Fig ).
Skull large (mean ONL = 27.2, mean CLM = 4.1, Table 4). Rostrum much longer than other members of the ‘ H. anselli ’ group (LN/ONL = 37.3%), with nasals exceeding 9.3 mm ( Table 4). Upper incisors generally orthodont, but a few slightly opisthodont. Incisive foramina fall short of upper tooth row crown but may reach alveoli. T3 on M 2 is large. Braincase elongate rather than rounded or globular. Hamular process of the squamosal thin, allowing for a large subsquamosal fenestra (ca. 30% of post glenoid foramen). Maxillo-palatal suture at third lamina of the M 1. Post palatal foramina large (0.7–0.9 mm), beginning between M 1 and M 2 and continuing through the 1 st third or half of the M 2. Frontoparietal suture V-shaped. Zygomatic plate narrow (mean breadth = 2.3 mm) and orthogonal to the long axis of the skull. Mesopterygoid fossa more rectangular at rostral end.
As a member of the Hylomyscus anselli group, the following characters are relevant: 1) mammary formula 2+4, 2) upper incisors orthodont with some individuals (5 of 33) slightly opisthodont, 3) T3 on M 1 is large and is more or less equal in size to T1, but T1 is deflect- ed further posteriorly ( Fig. 7a View Fig ), 4) T9 on M 1 is distinct
( Fig. 7a View Fig ), 5) interorbital constriction has a weak shelf, 6) rostral length is long, LN/ONL = 37.3%, 7) incisive foramen is short, falling just short of the M 1 or barely meeting the beginning of the alveolus, 8) the hamular strap is thin allowing for well-developed subsquamosal foramen but which is proportionately smaller than in the two new DRC species ( Figs 6e–f View Fig vs. Figs 12e–f View Fig ).
Habitat. Mbizi is the largest area of montane cloud forest (ca. 2,000 ha) remaining on the denuded Ufipa Plateau. All of the extant forest is contained within the Mbizi Forest Reserve and is discontinuous with forest patches interspersed with grasslands. There is very little continuous canopy cover due to removal of commercially valuable
Reproduction. Of the 33 examples of the new species collected (July–Aug 2001), there were 18 males and 15 females. All can be considered adult (3 rd molars in advanced wear). Of the 15 females, 14 were inspected internally: 7 were pregnant, 7 were not. All pregnant females had either 4 or 5 embryos with an average crown rump length of 12–13 mm. The pregnant females averaged 28 g in weight while those that were not pregnant weighed an average of 25 g. All males were adult with scrotal testes. The entire population had well-worn molars, at least in advanced wear stage IV (Verheyen & Bracke 1966).
timber species and exploitation for firewood and charcoal ( Rodgers et al. 1984). The forest is on the eastern facing escarpment overlooking the Rukwa Trough. Surveys of the vegetation at Mbizi include those by Mtuy & Mkude (1974), Rodgers et al. (1984), and Rufo & Mabula (1987). The forest canopy reaches 25 m in places with dominant tree species being Aguarista salicifolia , Allophyllus abyssinicus , Croton megalocarpus , Macaranga capensis , Neoboutonia macrocalyx , Olea chrysophylla, Olinia rochetiana, and Prunus africana ( Rodgers et al. 1984) . The understory is between 8–20 m with the most commonly encountered tree species being: Bersama abyssinica , Cathula edulis, Clerodendron sthulmanii, Bridelia brideliifolia, Polyscias fulva , and Rhus natalensis ( Rodgers et al. 1984, Rufo & Mabula 1987). The most striking aspect of Mbizi forest is scattered Euphorbia amplophylla that emerge above the canopy up to 35 m ( Rodgers et al. 1984). Forest cover has been fragmented by past fires and smaller patches are now isolated on the periph- ery and in sheltered valleys. These are surrounded by species-rich grasslands maintained by nearly annual fires ( Rufo & Mabula 1987). The central forest block is more or less continuous and covers an area of over 2000 ha. However, much of this is disturbed as the reserve is surrounded by villages and heavily exploited for firewood and charcoal. The area has many endemic plants (e.g., Brillantaisia richardsiae , Glossostelma mbisiense , Pachycarpus pachyglossus , Spermacoce azurea , Sebaea perpava , Afrotysonia pilosicaulis ) and several undescribed plant species including a possible new species of Ocotea (Q Luke, pers. comm.).
Distribution. Known only from two montane forest localities within Mbizi Forest, SW Tanzania: the type locality at ½ km S and 3 km E Wipanga, 2300 m (31.6667° E, 7.875° S) and a second locality ½ km N, 4 km E Wipanga, 2200 m (31.6694° E, 7.8639° S).
Etymology. Named for William T. Stanley (1957–2015) who directed the collection of all known specimens (n = 33) of this species from the Mbizi Mountains of Tanzania in 2001 as well as the type specimen of the other three species described in this manuscript (and many more). We recommend “Stanley’s wood mouse” as an English common name.
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Departamento de Geologia, Universidad de Chile |
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