A fruit wing of Shorea Roxb. from the Early Miocene sediments of Kachchh, Gujarat and its bearing on palaeoclimatic interpretation

Abstract

A new fossil fruit wing of Shorea Roxb. belonging to the family Dipterocarpaceae is described from the Early Miocene sediments of Kachchh, Gujarat. It resembles best the extant species Shorea macroptera Dyer, which is a prominent member of the tropical evergreen forests of the Malayan Peninsula. The present finding, along with the other megafossil records described from the same area, indicates a typical tropical vegetation with a warm and humid climate at the time of deposition in contrast to the present day xeric vegetation in the area. As the family Dipterocarpaceae no longer exists in western India, it is essential to discuss the time of its extinction and possible causes, which may include drastic changes in the climate of the region. The present finding also supports the theory of a Malaysian origin for the family in contrast to the hypothesis of a Gondwanan origin.

Winged fruits and associated leaves of Shorea (Dipterocarpaceae) from the Late Eocene of South China and their phytogeographic and paleoclimatic implications

“…In the Middle Miocene, climate became warmer and moister because of the Himalayan uplift (Morley, 2000). Dipterocarps underwent a drastic increase in geologic distribution, diversity, and abundance, becoming the dominant group in the forests of the Indian subcontinent (Awasthi, 1992; Guleria, 1992; Shukla et al, 2012). Nevertheless, increasing aridity and seasonality in the Late Miocene and Pliocene led to their gradual disappearance along with rain forests across most parts of India (Morley, 2000).…”

“…Nevertheless, increasing aridity and seasonality in the Late Miocene and Pliocene led to their gradual disappearance along with rain forests across most parts of India (Morley, 2000). A small proportion of dipterocarps were confined to refuges in Sri Lanka and the western Ghats and evolved into the current 29 species within six genera (Morley, 2000; Shukla et al, 2012).…”

“…Dipterocarps are well represented in Tertiary floras of Southeast Asia and Africa, but these occurrences are principally represented by fossil woods with fewer leaves and pollen (Gregory et al, 2009). Convincing reproductive remains are rare, and to date, only a few authenticated winged fruits have been described from the Tertiary of Sumatra, India, and China (Ashton, 1982; Prasad, 2006; Khan and Bera, 2010; Shi and Li, 2010; Shukla et al, 2012).…”

“…To date, only two fossil fruits representing Shorea have been reported from the Miocene of India (Khan and Bera, 2010; Shukla et al, 2012). These fossils differ from the specimens described here in possessing a linear lanceolate calyx lobe, a smaller fruit body, and fewer (7–11) primary veins (Shukla et al, 2012).…”

Palynological and paleobotanical investigations of Paleogene sections in the Maoming basin, South China

“…The fossil leaves and wood remains of this genus are reported from Cenozoic sediments of India (Awasthi, 1992;Guleria, 1992). The fossil repro ductive structures of Shorea are rare: now, they are known only from Miocene of India (Khan and Bera, 2010;Shukla et al, 2012). The finds of the oldest reli ably identified representatives of the Dipterocar paceae in Eocene of South China are of great signifi cance for understanding the origin, diversification, and phytogeography of this taxon.…”