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HOME --> CLASS MAMMALIA
--> ORDER RODENTIA
--> SUBORDER SCIUROMORPHA
--> FAMILY Gliridae
SUBFAMILY Graphiurinae
| Author: | Winge, 1887. | | Citation: | E Museu Lundii, 1: 109, 123. | | Comments: | Results of Wahlert et al. (1993) identified the Graphiurinae as the earliest or most primitive branch of glirids, a position also supported by Meng (1990) and Yachontov and Potapova (1991). Hartenberger (1994) considered many aspects of graphiurine morphology to be primitive, and postulated that graphiurines may have been in Africa since the Miocene; late Miocene graphiurines are recorded from Namibia (Mein et al., 2000a; Senut et al., 1992) and South Africa (Denys, 1990a). Vianey-Liaud and Jaeger (1996) placed Graphiurus in its own family; they considered Gliridae to be paraphyletic, and hypothesized that Graphiurus is closely related to anomalurids (a position not supported by other published works, see discussion under Gliridae). Daams and de Bruijn (1995) postulated that Graphiurus is a descendant of Eliomys, and included both within their Dryomyinae (along with Dryomys, Glirulus and Chaetocauda). Based on the longitudinal orientation of the Hunter-Shreger bands of incisor enamel, Koenigswald (1993, 1995) arranged Graphiurus within his derived "Group III" that also contained Muscardinus, Myomimus and Selevinia (he did not employ subfamily names to describe his groups). In a phylogenetic analysis based on analysis of mitochondrial genes, Bentz and Montgelard (1999) were unable to resolve the position of Graphiurus within Gliridae, but phylogenetic analyses of DNA nuclear fragments and mitochondrial 12S rRNA sequences reinforced the conclusions of Wahlert et al. (1993) in which Graphiurus constitutes one of the three primary evolutionary lineages in Gliridae and is basal to the lineages forming Glirinae and Leithiinae (Montgelard et al., 2003). Using molecular-clock estimates, Montgelard et al. (2003) estimated that the evolutionary radiation of species in Graphiurus began 8-10 million years ago, which predates the oldest fossil Graphiurus (about 5 million years old), but is consistent with occurrence of the late Miocene (10-11 million years old) Namibian graphiurine Otaviglis (Mein et al., 2000a). This age is roughly equivalent to the lower Vallesian of Europe at which time low sea levels may have facilitated extensive faunal interchange between Europe and Africa. Subsequent speciation in Graphiurus represents "a burst of evolution with rapid divergence from a single ancestral form . . . driven by novel ecological opportunities. . .," which is reflected in the strikingly greater number of species in Graphiurus compared with extant Eurasiatic glirid genera, and the short internal branches forming unresolved nodes among the species in the molecular analyses (Montgelard et al., 2003:1954). For synonyms see McKenna and Bell (1997). |
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