Abstract Detail

Paleobotany

xu, shenglan [1], Kodrul, Tatiana [2], Liu, Xiaoyan [3], Jin, Jianhua [4].

Early Oligocene Burretiodendron Rehd. from the Maoming Basin of Guangdong, South China.

The genus Burretiodendron Rehd. with six extant species is primarily distributed in tropical monsoon limestone forests of mainland Southeast Asia and southwestern China. Burretiodendron is very rare in the fossil record, only three fruit and leaf fossil species of the genus are known from the upper Miocene of southeastern Yunnan Province and the Oligocene of Guangxi Province, China.
New fruit fossils and associated leaves of Burretiodendron were recovered from the lower Oligocene Shangcun Formation, Maoming Basin, South China. Fruits are preserved as two-winged mericarp compressions, elliptic to obovate, 20-32.5 mm long, 10.5-23 mm wide, with rounded apex and acuminate base. Obovate to heart-shaped endocarp is centrally placed on the mericarp. Wing veins extend outward from the endocarp, craspedodromous, anastomosing and dichotomising but not forming elongated areoles. Wing epidermal cells are polygonal, arranged irregularly, with straight anticlinal walls; papillae and trichome bases are visible on abaxial side of the wing.
Associated fossil leaves are simple, unlobed, elliptic to ovate, with untoothed slightly sinuous margin. Leaf apices and bases were not preserved but cordate base might be reconstructed in some cases. Primary venation is actinodromous with three basal veins, secondary veins are brochidodromous, and tertiary veins are percurrent with opposite sinuous to straight course, occasionally alternate. Leaves are hypostomatic with abaxial epidermis showing irregularly distributed, randomly oriented stomata and trichome bases surrounded by five to seven radial epidermal cells.
Morphological comparison with extant and fossil Burretiodendron taxa indicates that new fruit fossils are most similar to the Oligocene species B. guangxiensis Dong et Sun and living species B. hsienmu Chun et How but differ in size and fruit shape. This is one of the earliest fossil record of Burretiodendron, providing additional evidence for the origin and early biogeographic history of this genus.

1 - Sun Yat-sen University, Biological Building Of Sun Yat-sen University,135?Xingang Road, Haizhu Area., Guangzhou, 44, 510275, China
2 - Geological Institute RAS , 7 Pyzhevsky Lane, Moscow, 119017, Russia
3 - Sun Yat-sen University, School Of Life Sciences, No. 135 Xingangxi Road, Guangzhou, 44, 510275, China
4 - Sun Yat-sen University, School Of Life Sciences, 135 Xingangxi Road, Guangzhou, Guangdong, 510275, China

Keywords:
Burretiodendron
early Oligocene
Maoming Basin
South China
limestone forest.

Presentation Type: Oral Paper
Session: PAL4, Paleobotany IV: Paleogene Paleobotany
Location: Tucson C/Starr Pass
Date: Tuesday, July 30th, 2019
Time: 4:45 PM
Number: PAL4005
Abstract ID:119
Candidate for Awards:None