Microgale cowani 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 : 814-815

Microgale cowani Thomas, 1882

Attributed material: Upper Stratum: 134 maxillary fragments, 346 mandibular rami; see Appendix.

No intact maxillae were observed amongst M. cowani ; a few specimens exhibit premolar eruption, while one individual shows a mixture of deciduous and erupting teeth. No deciduous teeth are evident in the mandibular rami of M. cowani , but a few specimens show p2 or p 4 in the process of eruption (Stage 2) and several with p3 erupting (Stage 3). Since the anterior region of the mandible is more fragile than the posterior region and the deciduous dentition more readily lost than the permanent dentition, it is difficult to judge what age classes are present in the subfossil sample. Toothwear of the molars is one criterion used as an approximate method for ageing mammals. Four wear classes were established indicating increasing maturity: unworn molars with clearly defined cusps in juveniles and young adults, slightly worn molars in older adults, and worn and very worn molars which indicate old individuals. The results for the mandibular rami of M. cowani showed that the proportions for three of the wear classes are roughly equivalent: 19% with worn or very worn molars, 23% with no wear and with cusp pattern clearly visible, 24% showing wear and the fourth category with a slightly higher proportion, 34%, with moderately well-defined cusps and slight wear.

There is no variation in size of the mandibular ramus between Modern and subfossil specimens of M. cowani (see Figure 10 ). The few contemporary specimens of M. cowani collected by Major at Antsirabe and Andranobe, from the area near the Children’s Cave, group towards the upper part of the range of the subfossils on ARL but the mid-part of the range on MH (see Figure 10 ); however, the sample size is too small for this observation to have any significance.

Figures

Figure 10. Measurements of subfossil specimens of Microgale cowani from the Children’s Cave in comparison with modern representatives of the species. Measurements in millimetres. ARL:ascending ramus length; MH: mandible height.