Microgale Thomas, 1882

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 : 813-814

Genus Microgale Thomas, 1882

Microgale is a diverse and highly speciose genus, currently understood to be represented in Madagascar by 21 species plus one extinct species ( Everson et al. 2016; Jenkins 2018; Jenkins et al. 2022) but suspected to include cryptic species that are in the process of investigation ( Olson et al. 2004; S.M. Goodman and L.E. Olson, pers. comm.). Most of the subfossil material of Microgale examined by Major was identified only to the generic level; however it is evident from some of his handwritten label names that he potentially recognised two or more different species. The current study confirmed the presence of two species of Microgale , M. cowani and M. pusilla , among the subfossils in the Children’s Cave. Both species are listed as of Least Concern on the IUCN Red List ( Stephenson et al. 2016).

Microgale pusilla and M. cowani are distinguished from each other by skull size but also based on dental morphology. The size difference between the two species of Microgale found as subfossils in the Children’s Cave is clearly shown in Table 4 and Figure 9 , with M. pusilla being noticeably smaller than M. cowani .

The dentition of M. pusilla is markedly smaller than that of M. cowani . In M. pusilla the talon of the second upper premolar (P3) is absent or reduced to a cingulum and two roots are present, the posterior root being very broad, whereas in M. cowani P3 has three roots and a talon is present. The first lower deciduous premolar (dp2) and adult (p2) in M. pusilla is caniniform with no anterior accessory cusp and a very small posterior accessory cusp and this tooth has a single root; dp2 and p2 of M. cowani have two roots and in p2 the protoconid has an anterior accessory cusp (paraconid) and posterior accessory cusp (hypoconulid). If the teeth are absent, identification may be determined by the corresponding number of root sockets at the P3 or p2 locus.

Figures

Figure 9. Differences in mandible size between the two subfossil species of Microgale recovered from Children’s Cave. Measurements in millimetres. ARL: ascending ramus length; MH: mandible height.