The Monito del Monte (“little monkey of the mountain”), the only extant member of the Order Microbiotheria, is a small mouse-sized marsupial, found only in southern and central Chile and southwestern Argentina (Animal Diversity Web, https://animaldiversity.org/accounts/Microbiotheria/).
While the stem groups of two other marsupial orders (Paucituberculata and Peramelemorphia) are represented in the study carried out by Beck et al (2022), only one stem-group member of the Microbiotheria is included in that study. However, an older study performed by Goin and Abello (2013), does provide a phylogenetic tree of 14 fossil species representing the microbiotherian stem group. That work provides the basis for the tree shown below:
While the stem groups of two other marsupial orders (Paucituberculata and Peramelemorphia) are represented in the study carried out by Beck et al (2022), only one stem-group member of the Microbiotheria is included in that study. However, an older study performed by Goin and Abello (2013), does provide a phylogenetic tree of 14 fossil species representing the microbiotherian stem group. That work provides the basis for the tree shown below:
Figure 1. Time tree of the stem-Microbiotheria
The oldest known member of the stem-Microbiotheria is Eomicrobiotherium gaudryi, described (under the name Coona gaudryi) from the Late Eocene (Bartonian) of Chubut province in southern Argentina (Simpson, 1964). Unfortunately, no images are available in the public domain either for this species or for any of the other species shown in the above tree.
No fossils are known from the crown group of the Microbiotheria.
No fossils are known from the crown group of the Microbiotheria.
References
Beck, R. M., Voss, R. S., & Jansa, S. A. (2022). Craniodental morphology and phylogeny of marsupials. Bulletin of the American Museum of Natural History, 457(1), 1-352.
Goin, F. J., & Abello, M. A. (2013). Los Metatheria sudamericanos de comienzos del Neógeno (Mioceno temprano, edad mamífero Colhuehuapense): Microbiotheria y Polydolopimorphia. Ameghiniana, 50(1), 51-78.
Simpson, G.G. 1964. Los mamíferos casamayorenses de la Colección Tournouër. Revista del Museo Argentino de Ciencias Naturales 1: 1–21.
Goin, F. J., & Abello, M. A. (2013). Los Metatheria sudamericanos de comienzos del Neógeno (Mioceno temprano, edad mamífero Colhuehuapense): Microbiotheria y Polydolopimorphia. Ameghiniana, 50(1), 51-78.
Simpson, G.G. 1964. Los mamíferos casamayorenses de la Colección Tournouër. Revista del Museo Argentino de Ciencias Naturales 1: 1–21.
Image credit
Header (Monito del Monte, Dromiciops gliroides, photographed in forest southeast of Valdivia, southern Chile: markc666, under non-commercial license CC BY-NC 4.0.
Header (Monito del Monte, Dromiciops gliroides, photographed in forest southeast of Valdivia, southern Chile: markc666, under non-commercial license CC BY-NC 4.0.