Development of cenogram technique over the past six decades with some insights into the varied habitats occupied by diverse mammalian communities across Spain, China, and India transiting the middle miocene climatic optimum

Abstract

The climatic evolution of the Neogene, with long-term cooling disrupted by the Middle Miocene Climatic Optimum (MMCO; ~17–14.75 Ma), arises as a suitable baseline to analyze the effects of these transcendent climatic changes on the mammalian community structures. The present investigation is an attempt to examine the palaeohabitat of a Neogene (Middle Miocene: ~15–11.5 Ma) geographically distant (i.e., from Spain, China, and India) extinct mammalian communities utilizing the cenogram approach (in both qualitative and quantitative framework). The detailed statistical analyses (presented herein) incorporating a total of eight mammalian communities allows us to infer predominance of Tropical Deciduous Forest environments between ~15 and ~11.5 Ma interval, with several pulses of distinctive aridity experienced by some communities thriving within the Iberian region. On the contrary, stable forested conditions were witnessed by the middle Miocene communities of Asia [i.e., the ~11.5 million-year-old mammalian community of Laogou (China), and the ~13.5 million-year-old mammalian community of Ramnagar (north India)]. Our present investigation also infers that additional mammalian remains (particularly of body mass of <35 kg) are warranted to decipher the habitat (based on cenogram approach) of the Middle Miocene (~13 Ma) mammalian community of Kalagarh (Himalayan Foreland Basin, north India) and the Middle Miocene (~14 Ma) mammalian community of Palasava (Kutch Basin, western India). Nonetheless, the Cenogram technique (being continuously developed over the past six decades) may become an important tool to decipher any habitat change(s) of western India’s mammalian communities considering renewed palaeontological efforts within the Neogene of the region.