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.     

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.     

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.     

First fossil hagfish (myxinoidea): a record from the pennsylvanian of illinois

A fossil hagfish (Myxinoidea), a new genus from the Pennsylvanian, shows tentacles, structures of the head skeleton and internal organs. No other fossils of this group have been reported. Although this new hagfish differs from living forms in position of the gills, feeding apparatus, and relatively well developed eyes, it is quite similar to its recent relatives. Thus, hagfishes have a long, conservative geological history. Cladograms showing myxinoids as a sister group to the vertebrates are supported.     

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.     

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.     

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 from paleosols for the geological antiquity of rain forest

Kaolinitic claystones in Paleozoic paleokarst underlying the Middle Pennsylvanian Fort Scott Limestone near Drake, Missouri, contain abundant fossil root traces. These include a surficial root mat as well as stout, woody, deeply penetrating root traces: a rooting pattern similar to that under rain forest. Also similar to soils of rain forest is the deeply weathered clay of the paleosol, in which minimal amounts of nutrient bases remain. Forest communities adapted to oligotrophic clayey substrates in humid climates existed at least 305 million years ago.     

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.     

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.     

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.     

Bile Acid secreted by male sea lamprey that acts as a sex pheromone

We show that reproductively mature male sea lampreys release a bile acid that acts as a potent sex pheromone, inducing preference and searching behavior in ovulated female lampreys. The secreted bile acid 7alpha,12alpha,24-trihydroxy-5alpha-cholan-3-one 24-sulfate was released in much higher amounts relative to known vertebrate steroid pheromones and may be secreted through the gills. Hence, the male of this fish species signals both its reproductive status and location to females by secreting a pheromone that can act over long distances.     

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.     

Which behavior does the lamprey central motor program mediate?

The isolated lamprey spinal cord, when bathed in 2 millimolar D-glutamic acid, will generate a pattern of motor neuron discharge that has generally been assumed to represent the central motor program for swimming. Motion pictures of behaving lampreys were analyzed by a computer algorithm to estimate undulatory movement parameters that could be directly compared with those generated during D-glutamate--induced undulations. The D-glutamate--induced movement parameters were significantly different from those observed during normal behaviors, including swimming, but accurately predicted the undulations produced by spinally transected adult lampreys.     

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.     

Three-Dimensional X-ray Reflections from Anthracite and Meta-Anthracite

Careful analysis of x-ray scattering intensities of demineralized metaanthracites and high-rank anthracites formed during the Pennsylvanian geological period has revealed the presence of three-dimensional (hkl) reflections of graphite, demonstrating unequivocally that coals graphitize with metamorphism. Graphitization has been observed also with a coal formed before the Cambrian period, much earlier than most coals. A significant degree of graphitization occurs by coalification when the graphite-like layers attain a size of 25 to 30 angstroms as compared to 100 A or more by the heat treatment of amorphous carbons.