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An unexpected late paroxyclaenid (Mammalia, Cimolesta) out of Europe: dental evidence from the Oligocene of the Bugti Hills, Pakistan

Eight isolated mammal molars were discovered in lower Oligocene deposits of the Bugti Hills, Pakistan (Paali Nala, DB-C2; lower Chitarwata Formation). Because of their unusual morphology, these molars have long remained enigmatic. Extensive comparisons with fossil eutherian and metatherian mammals and the recent description of new paroxyclaenids (Mammalia, Cimolesta) from the lower Eocene (Ypresian) of Europe have highlighted the plausible affinities of these teeth from the Oligocene of Pakistan and suggest a referral to Paroxyclaenidae. The dental morphology of this taxon is singular among Paroxyclaenidae, and as such it allows us to propose here a new species and a new genus: Welcommoides gurki. The occurrence of a paroxyclaenid in the Oligocene of Pakistan remains somewhat unexpected inasmuch as these mammals have so far been known only from the Eocene of Europe. At c. 4.2 kg, W. gurki is the largest paroxyclaenid ever discovered, and is assigned to the subfamily Merialinae, which became extinct in Europe around the Ypresian–Lutetian transition, long before the occurrence of this new taxon from Pakistan. Welcommoides has a suite of unusual characters compared with merialines, suggesting that this South Asian lineage had diverged for some time from its European Ypresian counterparts. Such a hypothesis is supported by the faunal similarities between European and Indian subcontinent faunas during the Ypresian. Moreover, our discovery strengthens support for the hypothesis that low latitudes of South Asia were a tropical refugium, at least during the first steps of the global climatic deterioration started at the Eocene–Oligocene transition.

FIG. 2. Upper teeth of Welcommoides gurki gen. et sp. nov. from the Paali Nala DBC2 locality (Dera Bugti locus C2; Bugti Member, lower Chitarwata Formation; Bugti Hills; Balochistan; Pakistan). A–B, UM/DBC 2230, right (R) DP4 in A, labial; B, occlusal view. C–D, UM/DBC 2228, RM1 in: C, labial; D, occlusal view. E–F, UM/DBC 2229, RM2 in: E, labial; F, occlusal view. G–H, UM/DBC 2236, left (L) M2 in: G, labial; H, occlusal view. I–J, UM/DBC 2231, LM3 in: I, labial; J, occlusal view. K–L, UM/DBC 2232, LM3 in: K, labial; L, occlusal view. M–N, UM/DBC 2234, LM3 in: M, labial; N, occlusal view. O–P, UM/DBC 2233, LM3 in: O, labial; P, occlusal view. Abbreviations: lc, lingual cingulum; mtl, metaconule; prc, precingulum; prl, paraconule; ps, parastyle; psc, postcingulum; ssc, second stylar cusp (cusp C); styl, pseudo-stylocone. Scale bar represents 2 mm.

References

Floréal Solé, Syed Rafiqul Hassan Baqri, Nayyer Iqbal, Ghazala Roohi, Mouloud Benammi, et al. 2024 – An unexpected late paroxyclaenid (Mammalia, Cimolesta) out of Europe: dental evidence from the Oligocene of the Bugti Hills, Pakistan – Papers in Palaeontology, 2024, 10 (6), pp.e1599 – Abstract PDF