Abstract Detail

Clarifying Early Euasterid Evolution: A Synthesis of Phylogeny, Morphology, and the Fossil Record

Manchester, Steven R [1], Stull, Gregory W. [2].

Where are they hiding? Tracing the elusive fossil record of Lamiidae.

Fossil occurrences of the Lamiidae are spread around the globe and include representatives of most major subclades, but the record is spotty and the quantity of reliable fossil occurrences varies greatly across the phylogeny. Informative records of the early-divergent portion of the clade include members of Icacinaceae s.s. (extant and extinct genera based on fruits and pollen), Eucommiaceae (Eucommia known from fruits and pollen), and Metteniusaceae (Platea pollen). These fossils indicate a broader geographic range for these families in the past than is seen today. The core lamiid clade (Lamianae), which includes 97 percent of the modern diversity of the Lamiadae, is known only from scattered fossil occurrences of Boraginales, Gentianales, Solanales, and Lamiales. The only convincing boranginalean fossil record is that of Neogene Lithospermum seeds. Gentianales are represented by Eocene and younger fruits and seeds of Rubiaceae, Bignoniaceae and Apocynaceae. Solanales are represented merely by fruit of Solanaceae (Physalis) and pollen of Convolvulaceae, wheras the Lamiales are best known in the fossil record from fruits of Oleaceae (Fraxinus). Although some modern genera of Lamiids can be traced back about 50 million years to the early Eocene—e.g. Eucommia, Iodes, Pyrenacantha—other Eocene Lamiids represent extinct character combinations that have led to the recognition of extinct genera (e.g. Palaeophytocrene, Sphaeriodes, Stizocarya). The fossil record of Lamiidae is primarily confined to the Cenozoic, and mostly younger than 60 million years. Why is it that so many extant genera of Lamiids are completely missing from the fossil record? Several factors are considered including preservation potential of diagnostic organs, geographic biases of paleobotanical field work, and lack of expert knowledge of diagnostic morphological characters.

1 - University Of Florida, Florida Museum Of Natural History, PO BOX 117800, Gainesville, FL, 32611, USA
2 - University Of Florida, Florida Museum Of Natural HIstory, Dickinson Hall, Museum Rd. And Newel Dr., Gainesville, FL, 32611, USA

Keywords:
Paleobotany
Lamiidae
fossil.

Presentation Type: Colloquium Presentations
Session: C3, Clarifying early euasterid evolution: A synthesis of phylogeny, morphology, and the fossil record
Location: Chatham Ballroom - C/Savannah International Trade and Convention Center
Date: Wednesday, August 3rd, 2016
Time: 10:00 AM
Number: C3007
Abstract ID:741
Candidate for Awards:None