What does Devonian mean?  What is a progymnosperm? —– READ ON!

In the Devonian Period (395-345 million years ago) this region was a shallow sea, filling up with clay and silt material.  This site near Gilboa was apparently a log jam which collected these primitive trees as they washed down a small stream.  Later, streams from the Catskill Mountains eroded this swampy area at the edge of the sea. 

Then two women enter the story at the New York State Museum in Albany:  one was Linda VanAller Hernick.  While growing up in Rensselaerville in the early 1960’s Linda’s father took the family on Sunday drives and often stopped at the outdoor exhibit of the stumps at Gilboa.  After a trip to the state museum, where she saw similar Gilboa stumps, she was captivated.   Linda began working at the state museum in the mid 1990’s after receiving a B.S. in botany from the College of Saint Rose.  There she met another state museum worker, Sharon Mannolini.  Sharon, growing up in Guilderland, also had an interest in rocks and fossils.  Her “mentor” and big brother Frank frequently brought her interesting rocks he collected during his outings in upstate New York. 

These two women had explored the Gilboa for only a year when Sharon, at the age of 35, was killed in a car accident in 2003.  After she died, her brother Frank discovered that she had saved every single rock he had given her (which he still has today).  This man, who at the time, had a series of jobs that included building boats, driving trucks, and operating bulldozers, started working temporarily at the state museum and eventually assumed his little sister’s job and began working with Linda at the Gilboa site.  Their goal was to find the upper part of the Gilboa stumps.  After several summers of back-breaking labor with hammer and chisel, a power lift and pickup truck, they did it!   These two state museum employees, driven by Linda’s fascination and Frank’s determination, have solved the riddle of what this planet’s oldest known tree is.  After collecting material that filled several metal shelves of the state museum’s paleobotany collection, they have reassembled two nearly complete trees.  They have finally revealed a full picture of this species which Frank has produced an excellent reconstructed drawing of.     The common name is Wattieza, and the scientific name is Eospermatopteris (Eo=dawn, sperm=seed, opteris=fern or feather like). 

Hernick and Mannolini were joined by Ed Landing (of the New York State Museum), William Stein (paleobotanist at Binghamton University), and Christopher Berry (of Cardiff University, UK.)  in the publication ”Giant cladoxylopsid trees resolve the enigma of the Earth’s earliest forest stumps at Gilboa“, in the scientific journal Nature, 446,904-907 (19 April 2007).     This large fern-like tree, probably up to 8 meters tall had anchoring roots and a trunk bearing large branches with frond-like leaves and cycad-like crown of similar fronds.  It reproduced by sporulation (no seeds) and probably formed the first forest habitat on Earth, removing carbon dioxide and adding oxygen to the atmosphere, establishing the opportunity for a new and varied fauna.   Approximate age:  380 million years ago.

 

These fern-like trees had wood trunks and, like other progymnosperms, were disseminated by spores that were liberated by sporangia (the sac in which spores are produced) clustered on the fertile parts of the branches.  The progymnosperms have been considered important in the evolution of seeds.  Many paleobotanist believe that the earliest seed plants evolved from progymnosperms which become heterosporous (more than one kind of spore).   They developed megaspores and microspores,  the progenitors of the female and male gametes which united to form the first seeds.