Fossil mycelium with clamp connections from the middle pennsylvanian

A mycelium with clamp connections and chlamydospores has been discovered within the wood of a Middle Pennsylvanian fern. This suggests that forms extant in the middle of the Pennsylvanian had life cycles conparable to some modern Basidiomnycetes.     

Middle pennsylvanian plant fossils: problematic occurrence in the bronx

A possible glacial boulder of undeformed and unmetamorphosed siltstone containing Middle Pennsylvanian plant fossils was recovered from the Bronx. The rock cannot be explained by known geologic relations and suggests the possibility of undetected outliers of Pennsylvanian rocks in the Hudson valley.     

Palaeosclerotium, a pennsylvanian age fungus combining features of modern ascomycetes and basidiomycetes

Fruiting bodies described previously as sclerotia of Palaeosclerotium pusillum are cleistothecium-like, enclosed structures, containing spores within an ascus. The cleistothecia are composed of hyphae having dolipore-like septa and are attached to vegetative hyphae having clamp connections. The unique combination of ascomycete-like reproductive bodies and basidiomycete-like hyphae present in this Pennsylvanian fungus suggests that there already existed, during the Middle Pennsylvanian period, a group of fungi intermediate between the Ascomycetes and Basidiomycetes.     

First fossil lamprey: a record from the Pennsylvanian of Illinois

A fossil record of lampreys has previously been unknown. A new genus demonstrates the presence of this group in the Pennsylvanian. The body outline, parts of the head skeleton, rasping tongue mechanism, gill basket, and other internal organs are preserved. The fossils are very similar in structure to modern forms. The absence of hagfish characters in the fossil supports the view that the common ancestor of lampreys and hagfishes lived prior to the Pennsylvanian.     

Possible early pennsylvanian ancestor of the cycadales

A specimen of Lesleya, previously known only as isolated sterile foliage, has been found with two rows of ovule-bearing receptacles on opposite sides of the petiole. This specimen is from the Lower Pennsylvanian (Namurian B or C) of western Illinois. The fertile portion of this specimen is similar to Phasmatocycas kansana Mamay from the Lower Permian of Kansas and Texas, which Mamay interpreted as an ancestral form to cycads. Phasmatocycas was found attached to the base of Taeniopteris by Gillespie and Pfefferkorn. The foliar portions, Lesleya and Taeniopteris, have many features in common; the major morphologic difference is curvature of the veins. Lesleya and its attached fertile petiole are proposed as ancestors of Taeniopteris and Phasmatocycas, and ultimately, the ancestors of modern cycads. This extends the age of known precursors of cycads back from the Early Permian to Early Pennsylvanian (about 320 million years ago), approximately 35 million years earlier.     

Sieve areas in fossil Phloem

Phloem tissue of the Pennsylvanian fern Etapteris is described from permineralized specimens. Sieve elements possess regularly aligned sieve areas containing pores on the radial walls. The presence of these structures provides a basis for comparison with the phloem of living ferns.     

Petrolacosaurus, the oldest known diapsid reptile

Petrolacosaurus, an Upper Pennsylvanian reptile, presents a combination of features that place it within a distinct family of the Eosuchia while also evidencing strong relationships to the ancestral reptiles. It is therefore the earliest and most primitive representative of the largest assemblage of fossil and living reptiles, collectively called diapsids.     

Evidence for endomycorrhizae in pennsylvanian age plant fossils

Fossil fungal chlamydospores from the tissues of a number of Pennsylvanian age fossil plants are described. Features such as size, shape, wall organization, and the structure of the subtending hyphal stalk suggest affinities with the modern endomycorrhizal fungus Glomus.     

Evidence of pollen tubes in paleozoic pteridosperms

A saccate pollen grain with a branched pollen tube has been discovered within the pollen chamber of a fossil seed-fern ovule of Middle Pennsylvanian age. This suggests that microgametophytes comparable to those of living gymnosperms were produced by some Paleozoic pteridosperms.     

Predation through geological time: evidence from gastropod shell repair

Warm-water marine gastropods from soft-bottom habitats show an increase in the incidence of breakage-resistant shell characteristics over geological time. The hypothesis that breakage became a more important component of selection in the middle of the Mesozoic Era is supported by the finding that frequencies of breakage-induced shell repair increased from the Pennsylvanian and Triassic periods to the Cretaceous, Miocene, and Recent.     

Ten-armed fossil cephalopod from the Pennsylvanian of Illinois

Jeletzkya douglassae Johnson and Richardson is described as the oldest known representative of an extant squid group. The species is known from a single specimen from the Middle Pennsylvanian of Illinois. This very unusual fossil consists of the complete tentacular crown and a fragile shell. The arms bear hooks in double rows.     

Iodide abundance in oilfield brines in oklahoma

Samples of subsurface water, oil, and rock from strata of Mississippian and Pennsylvanian age in the Northern Oklahoma Platform area were analyzed. Several of the water samples contained iodide at more than 500 parts per million. Analyses of the brines and rock indicated that the iodide originated organically.     

Cycads: fossil evidence of late paleozoic origin

Plant fossils from Lower Permian strata of the southwestern United States have been interpreted as cycadalean megasporophylls. They are evidently descended from spermopterid elements of the Pennsylvanian Taeniopteris complex; thus the known fossil history of the cycads is extended from the Late Triassic into the late Paleozoic. Possible implications of the Permian fossils toward evolution of the angiosperm carpel are considered.     

Evidence for a pollination-drop mechanism in paleozoic pteridosperms

A noncellular substance containing pollen and spores has been discovered protruding from the micropyle of a seed fern ovule of Middle Pennsylvanian age. This provides direct evidence that pollination-drop mechanisms comparable to those of many extant gymnosperms characterize some Paleozoic pteridosperms.     

Chytrid-like fossils of pennsylvanian age

Chytrid-like fungal sporangia are described occurring in saccate pollen grains of Pennsylvanian age. Both endo- and epibiotic sporangia are present, and may exhibit discharge papillae and a coarse rhizomycelium. Sporangial features, choice of substrate, and the presence of a light refractile body in presumed zoospores suggest relationships with the Chytridiales.     

Paleozoic sedimentary rocks in oaxaca, Mexico

Fossiliferous Cambrian, Ordovician, Mississippian, and Pennsylvanian rocks, never before found in southern Mexico, have been discovered in the Nochixtlán region. Superjacent unfossiliferous sedimentary rocks may be Permian in age. Early Paleozoic and late Paleozoic intervals of marine sedimentation were bounded by intervals of positive tectonism and erosion.     

Fossilized eggs in a pennsylvanian blastoid

A single specimen of Pentremites rusticus (Echinodermata, Blastoidea) from the Early Pennsylvanian of Oklahoma has hundreds of apparent eggs in one of its abnormal anal hydrospire groups. This rare occurrence suggests that female blastoids in this sexually dimorphic species had modified their anal hydrospiresfor brooding eggs instead of for normal respiration.     

Evidence of paleozoic chromosomes from lycopod microgametophytes

A Pennsylvanian arborescent lycopod cone, Lepidostrobus schopfii, has microspores that have been found to have intracellular features that are interpreted as nuclei and mitotic chromosomes. The cellularized gametophytes conform to the early stages of growth that occur in modern Selaginella microgametophytes. Since the megagametophyte of L. schopfii is similar in development to extant species of Isoetes, the fossil now is known to have portions of its life cycle in common with both Selaginella and Isoetes.     

Fossil plants and coal: patterns of change in pennsylvanian coal swamps of the illinois basin

Coal palynology and studies of petrified peat indicate major changes in coal-swamp floras and the botanical constituents of coal throughout Pennsylvanian time. The changes are the result of broad climatic shifts and local environmental factors. The most striking is the change from a lycopod-dominated flora to one in which tree ferns were the major element. This change occurred at the Desmoinesian-Missourian (Westphalian-Stephanian) boundary and is probably multicontinental in scope.