Paul Strother

geology & geophysics

 Paul Strother

Paul K. Strother, Research Professor, Fellow AAAS
Ph.D. Harvard University (1980)
B.S. Penn State University (1975)

INTERESTS:

Paleobotany, palynology, Precambrian paleobiology, and the origin of land plants. We are especially excited to be working on new discoveries of Cambrian cryptospores, evidence that land plants evolved much earlier than previously thought. For a more complete description of ongoing research, please see the Paleobotany Laboratory web site at Weston Observatory

CONTACT INFO:

Boston College Office: 617-552-3399
Weston Observatory Office: 617-552-8319
e-mail: strother@bc.edu
Personal Home Page:  www2.bc.edu/~strother

COURSES:

GE 146 - Origin & Evolution of Life (Spring 2009)
GE 335 - Topics in Geobiology (Spring 2009)

CURRENT GRADUATE STUDENTS AND PROJECTS:

Leslie Campbell Paleoecology of some glaucony bearing units of the Middle and Upper Cambrian of Laurentia.
David Li Quantification and analysis of micro-burrows in the Consasauga Group in eastern Tennessee.

M.S. ALUMNI AND PROJECTS:

Neal Grasso Effects of the evolution and expansion of the grassland biome on Miocene climate: a modeling/palynology study. (1999).

Selected Publications:

 

• Strother, P.K. A speculative review of factors controlling the evolution of phytoplankton during Paleozoic time. Revue de micropaléontologie (2007), doi:10.1016/j.revmic.2007.01.007.

• Strother, P.K., G.D. Wood, W.A. Taylor & J.H. Beck (2004) Middle Cambrian cryptospores and the origin of land plants. Memoirs of the Association of Australasian Palaeontologists 29:99-113.

• Baldwin, C.T., P.K. Strother, J.H. Beck & E. Rose (2004). Palaeoecology of the Bright Angel Shale in the eastern Grand Canyon, Arizona, U.S.A. Incorporating sedimentological, ichnological and palynological data, 213-236. In The Application of Ichnology to Palaeoenvironmental and Stratigraphic Analysis. McIlroy, D. (ed.). Geological Society of London, Special Publications, 228.

• Beck, J.H. and P.K. Strother. 2001. Silurian Spores and cryptospores from the Arisaig Group, Nova Scotia, Canada. Palynology 25: 127-177.

• Strother, P.K. 2000. Cryptospores: The origin and Early Evolution of the Terrestrial Flora,3-19. In R.A. Gastaldo and W.A. DiMichele (eds.) Phanerozoic Terrestrial Ecosystems. The Paleontological Society Papers, Vol. 6.

• Strother, P.K. and J. H. Beck. 2000. Spore-like microfossils from Middle Cambrian strata: expanding the meaning of the term cryptospore, 413–424. In M. M. Harley, C. M. Morton and S. Blackmore (eds.) Pollen and Spores: Morphology and Biology, Royal Botanic Gardens, Kew.

 

Selected Abstracts:

 

Cryptospores and the Origin of Land Plants

 

Paul K. Strother

 

Palæobotany Laboratory, Weston Observatory of Boston College, Department of Geology & Geophysics, 381 Concord Road, Weston, Massachusetts 02493 US

 

Evidence from microfossil cryptospores and small organic fossils (mesofossils) indicates that land plants (embryophytes) evolved prior to the Middle Cambrian. The earliest records of land plants are small cryptospore tetrads recovered from the Rome Formation in eastern Tennessee, USA. These are complemented by an extensive suite of cryptospore tetrads, dyads, polyads and monads recovered from several Middle to Upper Cambrian sites from both the eastern and western margins of the ancient Laurentian continent. Cryptospore wall ultrastructure varies from homogeneous to laminated, matching that seen in Caradocian (Ordovician) tetrads derived from putative sporangia of liverwort affinity and modern Riccia. Clusters of Cambrian cryptospores associated with recalcitrant tissues point toward an embryophytic rather than algal derivation. Small pieces of pseudo-cellular cuticles, similar to that seen in some Silurian preparations, have now been isolated. Recently discovered mesofossils of Upper Cambrian age are composed of a plexus of intertwined organic filaments. The filaments possess oblique cross walls, supporting their interpretation as the resistant protonemata of bryophytic gametophytes. A fair and balanced assessment of these fossils now supports the presence of a persistent subaerial bryophytic flora during most of the Cambrian. These new discoveries support the recognition of a persistent protonematal phase in plant life cycles as an important step in the evolution of plant adaptation to the terrestrial environment.

 

Paléobotanique et Evolution du Monde Végétal: Quelque Problèmes d'Actualité. Séminare International, Collège de France, Paris. May 23-25, 2007.

Life on Land during the Cambrian Period.

 

Paul K. Strother

 

Palæobotany Laboratory, Weston Observatory of Boston College, Department of Geology & Geophysics, 381 Concord Road, Weston, Massachusetts 02493 US

 

Palynological preparations from nearshore and estuarine mudstones of Cambrian age from the margins of Laurentia contain abundant non-marine cryptospores. These are sporelike cells, typically packaged as sets of dyads and tetrads, whose only crime is to lack the perfect symmetry of later forms that produced the trilete spores of higher land plants. In all other respects, the Cambrian cryptospores are compatible with an embryophytic derivation. Dyad and tetrad topologies match developmental variation observed in extant bryophyte and lycophyte sporogenesis. Non-tetrahedral forms of cryptospores have a persistent fossil record that extends well into the Silurian. Late Cambrian tetrads and dyads from Wisconsin are morphologically very close to Ordovician forms found elsewhere. Cryptospores are distinct from acritarchs and other kinds of fossil algae. Some cryptospore clusters are associated with organic coverings, others are found with receptacle-like structures. The Cambrian landscape was not one of tiny upright axes, these did not come about until the Silurian. Instead, it was likely populated by thalloid plants of an evolving bryophytic complex that occupied a wide range of mesic habitats.

 

Palæontological Association, 50th Annual Meeting, Sheffield, England. December 17-20, 2006.

Studies on the Devonian/Carboniferous Acritarch Decline

 

Michaud, John. R. and Paul K. Strother

 

Palæobotany Laboratory, Weston Observatory of Boston College, Department of Geology & Geophysics, 381 Concord Road, Weston, Massachusetts 02493 US

 

The Devonian/Carboniferous transition experienced secular changes in the global carbon cycle that were permanent and extremely significant for evolution of life on Earth. These include shifts in the distribution of carbon in various reservoirs, including standing carbon biomass, buried carbon and atmospheric CO2. The terminal Devonian also experienced one of the five greatest extinctions in the Phanerozoic shallow marine realm. We have begun to investigate the characteristics of the well-known acritarch decline that began in the Late Devonian. The research is based on taxon entries in the PalynoData dataset which have been progressively filtered to produce a curve that is more robust in terms of known/established acritarch species and their temporal distribution. The results of initial binning at the stage level show that acritarch taxa decline smoothly through the upper Mississippian and do not show a precipitous drop at any individual stage boundary. This acritarch curve appears to lag behind curves of atmospheric CO2 based on both modeling and isotopic studies and clearly postdates the Frasnian/Fammenian extinctions that characterize the shallow marine realm. The decline represents a loss of approximately 80% of genera beginning at the Tournaisian/Viséan boundary (345 Ma) with ~180 genera and continuing into the middle Bashkirian of the lower Pennsylvanian (~30 genera). Characteristics of the acritarch/prasinophyte groups that collectively go extinct during this interval will be examined to illuminate trends of the success or demise in such groups.

 

Comission Internationale du Microflore du Paléozïque, General Meeting 2006, Prague, Czech Republic. September 2-6, 2006.