Brachyuromys betsileoensis ( Bartlett, 1880 )

Denys, Christiane, Gabriel, Nadine W., Lalis, Aude & Jenkins, Paulina, 2024, Subfossil rodents and tenrecs of Children’s Cave, Madagascar, Journal of Natural History 58 (25 - 28), pp. 796-839 : 802-803

Brachyuromys betsileoensis ( Bartlett, 1880)

Most of the remains attributed to Brachyuromys by Major under the invalid name B. arvicoloides belong to the smaller species B. betsileoensis .

Attributed material: Lower Stratum: 1 maxilla; 1 mandibular ramus. Upper Stratum: 30 crania and maxillary fragments; 44 mandibular rami; 5 molars; see Appendix for details.

The two specimens from the Lower Stratum belong to a juvenile ( CD77 ) and an adult specimen ( CD78 ). They are both small but fit within the variability of the modern B . betsileoensis ( Table 1 ). The other specimens from the Upper Stratum are relatively similar in size to modern representatives but always fit within the smallest dimensions of the bivariate graphs ( Figure 3 ). They display lophs that are less oblique than those of B . ramirohitra and the longitudinal links between lophs are visible until an advanced stage of wear ( Figure 4a,b ).

Figures

Figure 3. Scatter diagram of modern Brachyuromys spp. with Children’s Cave, Antsirabe and Lavajaza specimens. Top: LS13: length of the upper molar row, WM1: width of M1. Bottom: abscissa: length of the mandible (LMDB), ordinate: L13: length of the lower molar row. Measurements in mm.

Figure 4. Rodent dental material from Childrens’s Cave.(a) Left upper molar row of B. betsileoensis NHMUK PV M 105365; (b) Right lower molar row B. betsileoensis NHMUK PV M 105196; (c) Right upper molar row R. rattus NHMUK PV M 105616; (d) Left upper molar row of M. cf. bastardi NHMUK PV M 102315; (e) Left upper molar row of M. cf. bastardi NHMUK PV M 102316;(f) Right lower molar row of Mus musculus NHMUK PV M 105164-sequence; (g) Right lower molar row M. cf. bastardi NHMUK PV M 105123; (h) Left m1 M. cf. bastardi NHMUK PV M 104879; (i) Left m1 and m3 M. cf. bastardi NHMUK PV M 105124.