Abstract Detail

Paleobotanical Section

Li, Gary [1], Guilliams, C. Matt [2], Carter, Benjamin [3].

Seeking answers in the ground: how fossil taxonomy can support currant phylogenetics.

Ribes (Grossulariaceae) comprises 150-200 species of shrubs distributed primarily in eastern Asia, western North America, and the South American Andes. In addition to extant diversity, Ribes has a rich fossil record, especially in North America. As part of a systematics project targeting all extant Ribes, we study fossil Ribes to calibrate phylogenetic estimates to absolute time. Here we present a pilot study examining species circumscriptions among the fossil Ribes taxa from the Creede formation of Colorado. In particular, taxonomists disagree on the circumscription of R. lacustroides, with Axelrod recognizing five different taxa that Hermsen recognizes only as a broadly circumscribed R. lacustroides. We use geometric and traditional morphometric data to characterize the wealth of morphological variation within R. lacustroides sensu Hermsen. We gathered both geometric and traditional morphometric data using high-resolution photos of 46 Ribes leaf fossils. The geometric morphometric data comprise 10 landmarks and the traditional morphometric data comprise 14 measurements. Both datasets were analyzed using multivariate statistics. We find moderate evidence for three or possibly four of Axelrod's five taxa, and conclude that this study illustrates the utility of morphometrics in the analysis of Ribes fossils. These data will be applied to our study of extant Ribes, particularly in the California where the genus has diversified extensively. Previously, we have used other Ribes fossils to demonstrate a Paleogene origin of major clades of California currants. Adding the fossil taxa from this study to our analyses may further inform divergence time estimates, biogeography, and tempo of diversification in California.

1 - San Francisco State University, Biology, 534 Hensill Hall, 1600 Holloway Ave., San Francisco, CA, 94132, USA
2 - University of California, Berkeley, Integrative Biology, 1001 Valley Life Sciences Bldg. #2465, University of California, Berkeley, Berkeley, CA, 94720-2465, USA
3 - Duke University, Biology, Box 90338, Durham, NC, 27708, USA

Keywords:
Ribes
Grossulariaceae
fossils
geometric morphometrics
Multivariate morphometrics
species delimitation.

Presentation Type: Poster:Posters for Sections
Session: P
Location: Eyrie/Boise Centre
Date: Monday, July 28th, 2014
Time: 5:30 PM
Number: PPB001
Abstract ID:284
Candidate for Awards:None