Data from: Palynology of a short sequence of the Lower Devonian Beartooth Butte Formation at Cottonwood Canyon (Wyoming): Age, depositional environments and plant diversity

The Beartooth Butte Formation hosts the most extensive Early Devonian
macroflora of western North America.  The age of the flora at
Cottonwood Canyon (Wyoming) has been constrained to the Lochkovian-Pragian
interval, based on fish biostratigraphy and unpublished palynological
data.  We present a detailed palynological analysis of the
plant-bearing layers at Cottonwood Canyon.  The palynomorphs
comprise 32 spore, five cryptospore, two prasinophycean algae and an
acritarch species.  The stratigraphic ranges of these
palynomorphs indicate a late Lochkovian - Pragian age, confirming previous
age assignments.  Analyses on samples from three different
depositional environments of the plant-bearing sequence – layers with in
situ lycophyte populations, flood layers that buried those populations and
an organic matter accumulation zone within a flood layer – demonstrate
distinct palynofacies. Comparisons between palynomorph and plant
macrofossil diversity reveal some discrepancies.  Whereas
zosterophylls and lycophytes, most diverse and abundant among the
macrofossils, have only one known corresponding spore type (assignable to
zosterophylls) in the palynomorph assemblage, the trimerophytes, rare in
the macrofossil assemblage, are represented by three spore
types.  Some of these discrepancies reflect taphonomic
differences between macrofossils and palynomorphs, others could be due to
the fact that the parent plants of most palynomorph types in the
Cottonwood Canyon assemblage are unknown.  These observations
emphasize the need for concerted efforts to bring together the knowledge
of macro- and microfloras within Early Devonian localities. 
Nevertheless, given the palaeophytogeographic significance of the
Beartooth Butte Formation flora, its palyno- and macrofossil assemblages,
taken together, provide new data relevant to future discussions of Early
Devonian biogeography.

比尔特霍特比尤特组（Beartooth Butte Formation）产出北美西部分布最广泛的早泥盆世（Early Devonian）大型植物群（macroflora）。位于怀俄明州卡顿伍德峡谷（Cottonwood Canyon）的该植物群年代，此前基于鱼类生物地层学（fish biostratigraphy）与未发表的孢粉学（palynological）数据，被限定为洛赫科夫阶-布拉格阶（Lochkovian-Pragian）间隔。本文对卡顿伍德峡谷含植物层位开展了详细的孢粉学分析，本次识别出的孢粉型（palynomorphs）包含32种孢子（spore）、5种隐孢子（cryptospore）、2种扁藻藻类（prasinophycean algae）以及1种疑源类（acritarch）物种。这些孢粉型的地层延限（stratigraphic ranges）指示其时代为洛赫科夫阶晚期-布拉格阶，证实了此前的年代归属。对含植物沉积序列三种不同沉积环境的样品——即原位石松类（lycophyte）植物群落层、埋藏该群落的洪水沉积层，以及洪水沉积层内的有机质聚集带（organic matter accumulation zone）——的分析显示出显著差异的孢粉相（palynofacies）。孢粉型与大型植物化石（macrofossil）的多样性对比存在一定差异：大型化石中多样性与丰度最高的工蕨类（zosterophylls）和石松类，在孢粉型组合中仅对应1种已知孢子类型（可归属于工蕨类）；而大型化石组合中较为稀有的三枝蕨类（trimerophytes），却有3种孢子类型代表。这些差异部分源于大型化石与孢粉型之间的埋藏学（taphonomic）差异，其余则可能源于卡顿伍德峡谷组合中多数孢粉型的母植物尚未被认知。上述结果凸显了整合早泥盆世遗址内大型与微型植物群研究的必要性。尽管如此，鉴于比尔特霍特比尤特组植物群的古植物地理学（palaeophytogeographic）意义，其孢粉与大型化石组合的综合数据，可为未来早泥盆世生物地理学（biogeography）的相关讨论提供新的依据。