Paragalago, Masters & Génin & Couette & Groves & Nash & Delpero & Pozzi, 2017
publication ID |
5D93F42-A273-4029-8ACB-EAF5D06969F5 |
publication LSID |
lsid:zoobank.org:pub:5D93F42-A273-4029-8ACB-EAF5D06969F5 |
persistent identifier |
https://treatment.plazi.org/id/2432A379-FFAF-FFC3-FC25-E23EFEB06713 |
treatment provided by |
Plazi |
scientific name |
Paragalago |
status |
gen. nov. |
PARAGALAGO View in CoL GEN. NOV.
h t t p:/ / z o o b a n k. o r g / u r n:l s i d: z o o b a n k. o r g: a c t: 4B5DD0A6-BB35-4C9E-B292-AA69A90D6431
Type species: Galago zanzibaricus Matschie, 1893 .
Included species: Galago granti Thomas & Wroughton, 1907 ; Galago cocos Heller, 1912 ; Galago demidovii orinus Lawrence & Washburn, 1936 ; Galagoides udzungwensis Honess, 1996 ; Galagoides rondoensis Honess, 1996 .
Diagnosis: Medium- to small-sized galagos ( 60–250 g), overlapping in size with Galago spp. and notably smaller than Sciurocheirus , Euoticus and Otolemur spp. Two species ( Paragalago orinus and Paragalago rondoensis ) show convergence in shape and size with Galagoides spp. Cranium is ovoid in shape, narrowing posteriorly, so that the pneumatized mastoids protrude. Premaxillaries protracted into a short tube that extends beyond lower jaw, as in Galagoides and Sciurocheirus ; the tubular extension in Paragalago is intermediate in length between the premaxillary tubes of the smaller and larger taxa.Anterior upper premolar (P 2) double-rooted, slender, but distally trenchant, as in Galagoides , not caniniform as in Euoticus and some Galago spp. Upper posterior premolars (P 4 s) are slightly larger than upper posterior molars (M 3 s) in most Paragalago specimens examined. In Galagoides M 3 is either larger or equivalent in size to P 4, while in Galago M 3 is much reduced. In Paragalago spp. , the M 3 hypocone is absent or minute but commonly observed in Galagoides spp. Coronoid processes delicate and curved, extending almost as far back as glenoid process, as in Sciurocheirus and Galagoides , not flattened and foreshortened, as in Galago and Euoticus .
Distribution: east of the Great African Rift.
Description: The snout is longer than in Galago , chiefly because premaxillaries extend well beyond the lower jaw, although not to the degree seen in Galagoides . The facial profile is distinctly concave ( Schwarz, 1931) as in Galagoides and Sciurocheirus , not straight or slightly convex as in Galago . Canines are slender. Anterior palatal foramina intrude between medial upper incisors, as in most galagid taxa. P 4 s fully molarized as in all crown galagids. In most Paragalago specimens examined, the M 3 had no hypocone, although a minute hypocone was present in some specimens from the Rondo Forest (probably P. rondoensis ). The degree of basicranial flexion is moderate, as seen in Galagoides , Otolemur and Sciurocheirus , not markedly flexed as in Euoticus and in Galago . Cranial shape is oblong as in Galagoides and Sciurocheirus , not globular as in Galago and Euoticus . Postorbital bars are generally slender, lacking the flanges sometimes seen in Euoticus , Galago and even Galagoides , usually in older specimens. Lower anterior premolars (P 2) are partially procumbent, but not to the same degree as the toothcomb, and never erect, as usually seen in male Galagoides ( Masters & Couette, 2015) . Parietal muscle scars/crests on either side of the medial suture outline a broad parietal plate over the orbits that narrows posteriorly.
The colour of the dorsal pelage is drab brown to cinnamon with varying degrees of rufous wash; outer surfaces of limbs are similar to dorsum in colouration. Individual hairs are slate grey near the root, contributing to the overall dark colouration. Hairs on ventrum and inner surfaces of limbs also have grey roots but cream buff to yellow buff tips, and the throat may be yellowish ( Groves, 2001). The ears are dark brown to black, depending on the species, and the tail varies from rufous brown to chocolate or even black. Paragalago granti and P. orinus have a darker tail tip. The cream to white nose stripe is emphasized by dark brown to black eye rings. Mature males of all species have unidentate penile spines ( Perkin, 2007). Species of Paragalago show behavioural differences that distinguish them in the field from both Galagoides and Galago taxa. Eastern dwarf galagos tend to leap more often than Galagoides , but not as frequently or extensively as Galago spp. Moreover, the three genera can be readily distinguished by vocalizations that differ in structure, in context and probably in function.
Notes: The new genus embraces several taxa originally allied with lesser or dwarf galagos, depending on body size. Paragalago zanzibaricus was described by Paul Matschie (1893) as a pale cinnamon-coloured lesser galago from western Zanzibar, although the species also occurs on the Tanzanian mainland (see Fig. 2). A recent conservation risk assessment conducted by the Primate Specialist Group of the International Union for the Conservation of Nature considered populations on small islands to be particularly vulnerable and deserving of subspecific recognition for the purpose of conservation monitoring. The Zanzibar population of dwarf galagos was hence designated as the subspecies P. z. zanzibaricus , while the mainland representatives of this species were classified as P. z. udzungwensis . Preliminary genetic studies of mainland and island populations (Pozzi, unpublished data) support their conspecific identity, but a more extensive comparison is necessary to confirm this.
Paragalago cocos View in CoL , which is morphologically indistinguishable from P.zanzibaricus View in CoL , was described by Heller (1912) from the Kenyan mainland. Paragalago granti View in CoL , with a type locality in southern Mozambique, has the largest geographical range among representatives of the genus, extending from the north-east of South Africa throughout Mozambique (and possibly parts of Malawi, where it has been referred to under the rubric Galagoides nyasae Elliot, 1907 ; Grubb et al., 2003) into southern Tanzania. The type and only known skin of Galago mertensi Frade, 1924 View in CoL , was collected at a locality not far west of the type locality of P. granti View in CoL and has, rightly or wrongly, been subsumed under this species ( Schwarz, 1931).
The two smallest members of the genus, P. orinus View in CoL and P. rondoensis View in CoL , are the most recent members of the eastern dwarf clade to have been accorded full species status. Paragalago orinus View in CoL is a montane endemic and occurs within a restricted habitat at high altitude in the Udzungwa and Uluguru mountains of Tanzania. Paragalago rondoensis View in CoL has a highly fragmented range in scattered lowland forest patches throughout Tanzania but is no longer considered to be of critical conservation concern (A. Perkin, personal communication). The apparent heterochronic disjunction between the eruption of adult dentition and the cessation of growth in this species may explain why both it and the genus to which it belongs have defied characterization for so long.
Our demonstration that the eastern dwarf galagos constitute a genus entirely distinct from the western dwarf galagos reinforces the conclusions of Groves (in press) that the Eastern Arc Mountains and the Swahilian (Tanzanian/northern Mozambique) coastal forests constitute a separate subregion of the African fauna, the Zanj subregion. The Zanj mammalian fauna is unique and restricted and deserves the highest conservation priority.
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