Dentognathic remains of small bunodont anthracotheres were first described from the Miocene continental deposits of Indo-Pakistan almost two centuries ago. At Caribari (Garo Hills, Bengal, sometimes spelled Karibari) the association of a bunodont species, at the time called Anthracotherium silistrense Pentland, 1828 (based on an isolated upper molar) with a selenodont form of similar dimensions, now known as Sivameryx palaeindicus (Lydekker, 1877b) (based on a maxilla with D3/ and D4/) was the root of a great deal of confusion (Forster-Cooper, 1924; Matthew, 1929; Colbert, 1935; Pickford, 1987). Recall that this species was named only four years after the naming of the genus Anthracotherium Cuvier, 1822 (1824). A bunodont lower third molar of an anthracothere from Caribari presented to the NHMUK in 1842 as part of the Cautley collection, but that remained undescribed until recently (Lihoreau et al. 2004), throws a great deal of light on the taxonomy of the bunodont species, but when described by the latter authors its locality was said to be unknown, a conclusion undoubtedly due to the fact that its catalogue number was misread as NHMUK M 19442 instead of NHMUK PV OR 19042 (see below). Examination of the OR catalogue at the NHMUK indicates that the specimen was collected at Caribari, the same locality as two other anthracothere fossils (OR 19040, a maxilla of a juvenile selenodont anthracothere, and PV OR 19041, an isolated M3/ of a small bunodont anthracothere). The bunodont lower and upper third molars from Caribari are compatible with each other in morphology and dimensions, on which basis it is concluded that they represent a single species, in recent literature known as Microbunodon silistrensis. Because of this discovery, the previous attribution of the Indo-Pakistan small bunodont anthracotheres to the genus Microbunodon requires re-assessment. The morphological differences concerning the mandibles of European Oligo-Miocene species and the Miocene ones from Indo-Pakistan evoked by Lihoreau et al. (2004), opens the possibility that there are two or more genera involved. The anterior parts of mandibles from Indo-Pakistan are scarce (Colbert, 1935; Lihoreau et al. 2004) and no skulls have been described, which hinders comparisons between them and the European forms. Comparison of the augmented sample of Indo-Pakistan small bunodont anthracotheres with specimens from Europe reveals that they differ from Microbunodon Depéret, 1908, and Microselenodon Depéret, 1908, as suspected by Colbert (1935) who wrote that the Siwalik forms might be included in Microselenodon but because the latter genus was poorly defined it was better to leave the Indian fossils in Anthracotherium. The newly available samples from Europe (La Milloque) and Indo-Pakistan, especially the undescribed material from Ramnagar which was consulted on Morphosource (Patel et al. 2022), provide additional information that clarifies the affinities of the ‘Siwalik’ taxa. The additional material from La Milloque, France (Brunet, 1968; Lihoreau et al. 2004) was for a long time included in Microbunodon minimum but, because Anthracotherium minimum is the type species of Microselenodon, and because it clearly differs in morphology and dimensions from the type species of Microbunodon (Mb. laharpei (Renevier, 1879)) the Milloque species should be classified in Microselenodon. The outcome, as suspected by Colbert (1935) is that the ‘Siwalik’ forms are not particularly close to Microselenodon, nor to Microbunodon, and they also differ sufficiently from Anthracotherium to necessitate the erection of a new genus, herein called Garobunodon, named for the Garo Hills from which the type species, previously known as Anthracotherium silistrense, was collected. Metric analysis of the small bunodont anthracotheres from the Miocene deposits (Siwaliks, Bugti, Sind etc.) of Indo-Pakistan reveals the presence of three size groups, the largest one containing the holotypes of two species (Anthracotherium silistrense (Pentland, 1828) and Microbunodon milaensis Lihoreau, Blondel, Barry & Brunet, 2004), the medium-sized one containing the holotypes of two species, in the order of naming: Microbunodon punjabiensis (Lydekker, 1877a) and Microselenodon mus (Pilgrim, 1908) and the smallest group contains the lectotype of Anthracotherium exiguum Forster-Cooper, 1924. It is concluded that the valid names of the species representing the three size groups are: 1) Garobunodon silistrensis for the largest of the three species, 2) Garobunodon punjabiensis for the medium-sized species, and Garobunodon exiguus for the smallest of the three. Concerning the age of the Caribari sedimentary deposits, the new interpretation of the fossils indicates that the association of two species of small anthracotheres (Garobunodon silistrensis and Sivameryx palaeindicus) in the Bengali deposits, accords best with an age estimate of Late Middle Miocene to basal Late Miocene (ca 12-9.5 Ma) instead of the traditional view that the deposits were of Early Miocene age.
