Graduation Date

Spring 2018

Document Type

Thesis

Program

Master of Science degree with a major in Biology

Committee Chair Name

Alexandru Tomescu

Committee Chair Affiliation

HSU Faculty or Staff

Second Committee Member Name

Michael Mesler

Second Committee Member Affiliation

HSU Faculty or Staff

Third Committee Member Name

Gar Rothwell

Third Committee Member Affiliation

Community Member or Outside Professional

Fourth Committee Member Name

Ignacio Escapa

Fourth Committee Member Affiliation

Community Member or Outside Professional

Subject Categories

Botany

Abstract

Diverse in modern ecosystems, mosses are dramatically underrepresented in the fossil record. Furthermore, most pre-Cenozoic mosses are known only from compression fossils, which lack detailed anatomical information. Lower Cretaceous deposits at Apple Bay (Vancouver Island, British Columbia, Canada) contain a diverse anatomically preserved flora that includes numerous bryophytes, many of which have yet to be characterized. Among them is a polytrichaceous moss that is described here as Meantoinea alophosioides gen. et sp. nov. Meantoinea alophosioides represents the first occurrence of gemma cups in a fossil moss and is the oldest unequivocal record of Polytrichaceae, providing a hard minimum age for the group of 136 Ma (Valanginian). In order to assess the phylogenetic relationships of fossil Polytrichaceae (including Meantoinea) and compare hypotheses of relationships recovered using molecular vs morphological methods, I conducted a comprehensive morphology-based phylogenetic study of the family. This phylogenetic study used a dataset of 100 morphological characters scored for 44 species of acrocarpous mosses, and parsimony as the optimality criterion. Results of the phylogenetic analysis suggest that morphology is useful in resolving phylogenetic relationships in the Polytrichaceae and that both fossil Polytrichaceae have stable phylogenetic relationships. However, rooting experiments demonstrate that there is no superior way to root analyses and indicate that relationships within the family are best evaluated using unrooted networks without outgroup taxa. These rooting problems suggest that additional information is needed to understand the phylogenetic relationships of Polytrichaceae. Such additional information could come from fossils of stem group polytrichaceous mosses, which await discovery.

Citation Style

American Journal of Botany

Included in

Biodiversity Commons

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