Deomyinae Thomas 1888

Deomyinae Thomas 1888, Proc. Zool. Soc. Lond., 1888: 132.

Synonyms: Acomyinae Dubois, Catzeflis, and Beintema 1999; Acomyinae Michaux and Catzeflis 2000; Deomyes Thomas 1888 .

Genera: 4 genera with 42 species:

Genus Acomys I. Geoffroy 1838 (19 species)

Genus Deomys Thomas 1888 (1 species)

Genus Lophuromys Peters 1874 (21 species)

Genus Uranomys Dollman 1909 (1 species)

Discussion: Up to 1999 the clade containing Acomys was informally referred to as "acomyines" (Hänni et al., 1995; E. Verheyen et al., 1995, 1996 b). Dubois et al. (1999:181-182) wrote that " Acomys and Uranomys constitute a monophyletic clade at the subfamily level, denoted ‘Acomyinae’ and noted "throughout this paper, we will use the term Acomyinae for the clade containing Acomys and Uranomys ." Later Michaux and Catzeflis (2000:286) indicated that "Following Hänni et al. (1995, p. 132), we name ‘acomyines’ or [provisionally] ‘Acomyinae’ as the clade containing the genera Acomys, Deomys, Lophuromys, and Uranomys ." Acomyinae as used by Dubois et al. is unavailable because it was unaccompanied "by a description or definition that states in words characters that are purported to differentiate the taxon" or "a bibliographic reference to such a published statement," which is stipulated by the fourth edition of the International Code of Zoological Nomenclature (International Commission on Zoological Nomenclature, 1999: Articles 13.1, 13.2), and Acomyinae as proposed by Michaux and Catzeflis cannot formally stand as a family-group name because its formation does not satisfy requirements described in articles 16.1 ("Every new name published after 1999, including new replacement names (nomina nova), must be explicitly indicated as intentionally new" and 16.2 ("a new family-group name published after 1999 must be accompanied by citation of the name of the type genus") of the fourth edition of the Code (ICZN, 1999).

Lydekker (1889:1418) wrote that "The subfamily Deomyinae is only known by Deomys, of the Congo Valley, which has upper molars intermediate in structure between those of the preceding [ Hesperomys] and following subfamilies [ Murinae]." The earliest reference, however, to a formal group equivalent to subfamily rank is Thomas’s (1888 c) Deomyes. After describing Deomys ferrugineus, Thomas wrote that "In the complete systematic arrangement of the Muridae, therefore, we shall have to look upon Deomys as forming by itself a special section, the Deomyes, intermediate between the Mures [modern Murinae] and Criceti [equivalent to modern New and Old World Cricetidae and Malagasy Nesomyinae]." Ellerman (1941:317) proposed Deomyinae, mostly because "the zygomatic plate and infraorbital foramen... appear unique," listed Thomas’s Deomyes as a synonym, but was apparently unaware of Lydekker’s use. Because Deomys, the type genus for Deomyes, which was clearly used by Thomas to designate a suprageneric rank, is a member of the clade also containing Acomys, Lophuromys, and Uranomys, Deomyinae is available as the formal name of the subfamily.

From the time that Dollmann described Uranomys in 1909, researchers have appreciated the morphological resemblance between it, Acomys, and Lophuromys, especially in pelage texture, palatal configuration, and molar occlusal patterns (Denys et al., 1992; Denys and Michaux, 1992; Heim de Balsac, 1963; Heim de Balsac and Lamotte, 1958; Heller, 1911; Hinton, 1921; Ingoldby, 1929; Misonne, 1969; Rosevear, 1969; Thomas, 1910 d). But it has been the accumulation of nonmorphological evidence that has really revealed the monophyletic unity of these three genera and their phylogenetic isolation from the rest of Murinae . Immunological experiments (Fraguedakis-Tsolis et al, 1993; Hammer et al., 1987; Montgelard, 1992, including Uranomys; Sarich, 1985) and analysis of amino acid sequences of insulin (Graur, 1994) identified Acomys as being as distant from Murinae as are some of the other subfamilies of Muridae (Wilson et al., 1987) . These results, and the bond between Acomys and Uranomys, were also indicated by chromosomal data (Viegas-Péquignot et al., 1986), analyses of allozymic variation (Bonhomme et al., 1985), and early DNA/DNA hybridization experiments (Catzeflis, 1990). A subsequent DNA-DNA hybridization study by Chevret et al. (1993 a) sampled Acomys, Uranomys, and Lophuromys, and identified them as a monophyletic clade, a conclusion supported by analysis of albumin immunology (Watts and Baverstock, 1995 b). Phylogenetic analyses of mitochondrial 12S and rRNA sequences (Hänni et al., 1995), nuclear pancreatic ribonuclease A gene sequences (Dubois et al., 1999), and mtDNA cytochrome b sequences (E. Verheyen et al., 1995) of the combination Acomys-Uranomys or Acomys-Lophuromys added additional molecular evidence for the reality of the clade. Analysis of highly repeated sequences of nuclear genome (LINES) identified a DNA element, Lx, which is unique to Murinae but absent from Acomys, Uranomys, and Lophuromys (Furano et al., 1994; Pascale et al., 1990; Usdin et al., 1995). Samples of Deomys were ultimately added to those of the other three genera and incorporated in phylogenetic analyses of sequences from mtDNA cytochrome b (E. Verheyen et al., 1996 b, Lophuromys and Deomys); the nuclear protein-coding gene LCAT (Michaux and Catzeflis, 2000); LCAT in combination with von Willebrand Factor (vWF) (Michaux et al., 2001); and the combination of DNA/DNA hybridization experiments, complete mitochondrial 12S and rRNA, and nuclear LCAT. Results strongly corroborated the distant relationship of Acomys, Uranomys, and Lophuromys to the rest of murid rodents and demonstrated unequivocally their close phylogenetic association with Deomys . A contrary view based on phylogenetic analyses of complete cytochrome b sequences by Martin et al. (2000) left the position of Acomys unresolved relative to the other murine genera examined. Chevret and Hänni (1994) provided an excellent review of the molecular and biochemical results and their limitations involving Acomys and its relatives.

Systematists agreed that Acomys and the other deomyines should be excluded from Murinae but had not identified a sister group (Chevret and Hänni, 1994; Dubois et al., 1999). DNA/DNA hybridization experiments (Catzeflis, 1990; Chevret et al., 1993 a) and analysis of DNA sequences from the fifth exon of the KBP gene (Agulnik and Silver, 1996) indicated Acomys, Uranomys, and Lophuromys to be phylogenetically closer to gerbillines than murines. Watts and Baverstock (1995 b), however, suggested the Acomys clade to possibly be the sister group to the rest of Murinae . Michaux and Catzeflis (2000:289) thought their molecular results provisionally confirmed a sister group relationship between Gerbillinae, Deomyinae, and Murinae, "implying a later separation between them with regard to the other subfamilies of Muridae ." The reconstruction of phylogenetic relationships based on analyses of combined LCAT and vWF sequences, "provides a clear and strong picture: acomyines [=deomyines] cluster with gerbillines..., and these two lineages are sister to murines" and "According to the molecular-clock analysis, the separation between the three subfamilies appeared 17.9-20.8 MYA [Early? Miocene]", which " was characterized by changes in climate which favored the spread in Europe, Africa, and America of allochthonous rodent groups probably coming from Asia" (Michaux et al., 2001:2026). The sister-group relationship of gerbillines and deomyines and their inclusion with murines in a monophyletic clade is substantiated by analyses of nuclear IRBP sequences (Jansa and Weksler, 2004). However, results combining DNA/DNA hybridization experiments with analyses of mitochondrial and nuclear gene sequences defined a clade formed of gerbils, murines, and deomyines but could not decipher the relationships among these three subfamiles, and Chevret et al. (2001) suggested that using other molecules (mainly protein-coding genes that evolve slowly), repeated elements, and a variety of morphological data may resolve sister-group affinities among the three subfamilies.

Reproductive biology of Acomys is special among murines (Dieterlen, 1961, 1962, 1963). Spermatozoal morphology described for samples of Acomys, Lophuromys, and Uranomys, seems to support their isolation from the rest of the genera sampled in Murinae (Baskevich and Lavrenchenko, 1995; Breed, 1995 d), and Breed (1995 d:418) suggested that the Acomys-Uranomys lineage "diverged from the base of the Murinae-Otomyine clade." Breed (1995 a) also noted that spermatozoal morphology of Lophuromys is "totally different" from that in Acomys and Uranomys as well as the other African murines sampled. A resistant-fit theta-rho analysis surveying magnitude and direction of positional changes of homologous landmarks on M1s grouped Acomys with Murinae and was equivocal in evaluating relationships among Acomys, Uranomys, and Lophuromys (Xu et al., 1996) . To date, no spermatozoal traits or other morphological characters have been identified as synapomorphies to supplement the biochemical and molecular data to define Deomyinae (Chevret et al., 2001).