J Syst Evol

• Research Articles •    

First fossil evidence of Palaeocarya (Engelhardioideae: Juglandaceae) from India and its biogeographical implications

Taposhi Hazra1, Manoshi Hazra1,2, Sanchita Kumar1, Sumana Mahato1, Meghma Bera3, Subir Bera3, and Mahasin Ali Khan1*   

  1. 1 Palaeobotany and Palynology Laboratory, Department of Botany, Sidho‐Kanho‐Birsha University, Ranchi Road, Purulia 723104, India
    2 Presidency University, Calcutta University Road, 86/1, College Street, Kolkata, West Bengal 70073, India
    3 Centre of Advanced Study, Department of Botany, University of Calcutta, 35 B.C. Road, Kolkata 700019, India
  • Received:2020-05-10 Accepted:2021-02-07 Online:2021-02-19

Abstract: Even though presently indigenous to eastern Himalaya in India, no Engelhardioideae have been reported from the Cenozoic sediments of India till date. Here, we report the first Indian occurrence of a characteristic engelhardioid winged samaroid fruit having a tri‐lobed wing (oblong‐ovate median lobe and two lateral lobes) and a globose nut from the latest Neogene (Pliocene: Rajdanda Formation) sediments of Chotanagpur Plateau, eastern India. This is the first fossil evidence of relict family Juglandaceae from the Indian Cenozoic. We determine its taxonomic position on the basis of detailed macromorphological comparison with similar extant and fossil specimens and discuss its palaeoclimatic significance in terms of the present‐day distribution of modern analogous species. We assign this Pliocene winged fruit specimen to the morphogenus Palaeocarya sect. Monocosta Manchester and describe it as a new species, namely Palaeocarya indica Hazra, Hazra M & Khan sp. nov. Palaeocarya sect. Monocosta has rich fossil records from the Cenozoic sediments of Europe, North America, and eastern Asia (China, Korea), but the modern analog, Engelhardia, is presently native only to India and neighboring Southeast Asia. We discuss the possible causes of disappearance of Engelhardia from the present‐day vegetation of Chotanagpur Plateau. Its disappearance may be related to the gradual intensification of monsoonal rainfall seasonality since the Pliocene. Here, we also review in detail the biogeographic history of Palaeocarya sect. Monocosta and suggest its possible migration routes.

Key words: Eastern India, Engelhardia, Palaeocarya sect. Monocosta, palaeophytogeography, Pliocene, winged fruit