Abstract Detail

Paleobotany

DAntonio, Michael [1], Boyce, C. Kevin [2], Zhou, Wei-Ming [3], Wang, Jun [4].

Sigillaria from the Wuda Tuff: the implications of new species and internal anatomy for lepidodendrid life history reconstruction.

Thin (3-6 cm) arborescent lycopsid stems conforming to the genus Sigillaria have been discovered upright in situ in the Wuda Tuff, Inner Mongolia, China (Asselian). Given that a broad lycopsid tree, S. cf. ichthyolepis, was the sole arborescent lycopsid taxon previously known from the assemblage, the new fossils were initially assumed to be juveniles of this species when assessed in the field under active mining conditions. Following retrieval of these specimens, lab-based study indicated that major discrepancies exist between the leaf cushion morphology of these smaller axes and that of S. ichthyolepis. Additionally, anatomical and morphological features of the plants preclude all possible geometric transformations by which the smaller Sigillaria stems could be interpreted as juveniles of the larger Sigillaria trees. Two new morphospecies of Sigillaria are recognized from among the thin axes: S. pfefferkornii and S. wudensis, the first two sub-canopy species of the genus. Moreover, proximal stump casts of three S. cf. ichthyolepis and six S. pfefferkornii or S. wudensis individuals exhibit traces of internal anatomy, and all—including the larger S. cf. ichthyolepis stumps—display thin or absent periderm, suggesting that the big trees were never thin saplings. This investigation provides a methodology for evaluating whether two differently sized fossils may represent early and late ontogenetic stages of the same plant and suggest that we lack an accurate search image for juvenile arborescent lycopsids given that the sapling model fails here.

1 - Stanford University, Geological Sciences, 450 Jane Stanford Way, Building 320, Stanford, CA, 94305, USA
2 - Stanford University, Geological Sciences, 450 Jane Stanford Way, Bldg. 320, Stanford, CA, 94305, United States
3 - Nanjing Institute of Geology and Palaeontology CAS, State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing 210008, Nanjing, China
4 - Nanjing Inst. Geol. 7 Palaeont. Academia Sinica, 39 East Beijing Road, Nanjing, 210008, China

Keywords:
life history
Lycopsid
Permian
anatomy
Developmental biology.

Presentation Type: Oral Paper
Session: PL1, Paleobotany: Cookson Student Presentations - Session I
Location: /
Date: Monday, July 19th, 2021
Time: 10:00 AM(EDT)
Number: PL1001
Abstract ID:308
Candidate for Awards:Isabel Cookson Award,Maynard F. Moseley Award