Arctinurus boltoni (Bigsby, 1825) - fossil trilobite from the Silurian of New York State, USA.
Trilobites are extinct marine arthropods. They first appear in Lower Cambrian rocks and the entire group went extinct at the end of the Permian. Trilobites had a calcitic exoskeleton and nonmineralizing parts underneath (legs, gills, gut, etc.). The calcite skeleton is most commonly preserved in the fossil record, although soft-part preservation is known in some trilobites (Ex: Burgess Shale and Hunsruck Slate). Trilobites had a head (cephalon), a body of many segments (thorax), and a tail (pygidium). Molts and carcasses usually fell apart quickly - most trilobite fossils are isolated parts of the head (cranidium and free cheeks), individual thoracic segments, or isolated pygidia. The name "trilobite" was introduced in 1771 by Johann Ernst Immanuel Walch and refers to the tripartite division of the trilobite body - it has a central axial lobe that runs longitudinally from the head to the tail, plus two side lobes (pleural lobes).
Classification: Animalia, Arthropoda, Trilobita, Polymerida, Lichidae
Stratigraphy: Rochester Shale, Niagaran Series (= Wenlockian), Middle Silurian
Locality: at or near Middleport, northwestern New York State, USA
Tags: Arctinurus boltoni Silurian Rochester Shale New York
Dictyonema sp. - dendroid graptolite from the Silurian of New York State, USA.
Graptolites are an extinct group of hemichordates that are most commonly preserved as carbonized compressions on shale bedding planes. They are typically not glamorous fossils, but they are critically important guide fossils and are widely used in biostratigraphy and for international correlation.
The most abundant group of graptolites in the fossil record is the graptoloids. Graptoloid graptolites typically resemble small hacksaw blades. Each “tooth” of the hacksaw blades housed a tentaculate, filter-feeding organism. The entire hacksaw blade is the graptolite skeleton, known as a rhabdosome - a nonmineralized colonial skeleton. Most graptolites were planktonic.
The second most abundant group of graptolites is the dendroids. Most dendroids attached to substrates and had colonial skeletons (rhabdosomes) that are generally broadly branching (conical to fan-shaped to shrub-like to flat spirals). A famous exception is Dictyonema (see this photo), a planktonic dendroid that had a worldwide distribution. Dictyonema floated freely in shallow and deep oceanic waters.
Other graptolite groups are very rare: the crustoids, tuboids, camaroids, and stolonoids.
Classification: Animalia, Hemichordata, Graptolithina, Dendroidea, Dendrograptidae
Stratigraphy: Rochester Shale, Niagaran Series (= Wenlockian), Middle Silurian
Locality: Middleport Quarry, town of Middleport northwestern New York State, USA
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Info. at:
en.wikipedia.org/wiki/Graptolite
Tags: Dictyonema Rochester Shale Silurian Middleport Quarry New York State grapotlite graptolites Dendrograptidae Dendroidea dendroid dendroids fossil fossils carbonization carbonized compression compressions
Desmograptus sp. - dendroid graptolite from the Silurian of New York State, USA.
Graptolites are an extinct group of hemichordates that are most commonly preserved as carbonized compressions on shale bedding planes. They are typically not glamorous fossils, but they are critically important guide fossils and are widely used in biostratigraphy and for international correlation.
The most abundant group of graptolites in the fossil record is the graptoloids. Graptoloid graptolites typically resemble small hacksaw blades. Each “tooth” of the hacksaw blades housed a tentaculate, filter-feeding organism. The entire hacksaw blade is the graptolite skeleton, known as a rhabdosome - a nonmineralized colonial skeleton. Most graptolites were planktonic.
The second most abundant group of graptolites is the dendroids. Most dendroids attached to substrates and had colonial skeletons (rhabdosomes) that are generally broadly branching (conical to fan-shaped to shrub-like to flat spirals). A famous exception is Dictyonema, a planktonic dendroid that had a worldwide distribution. Dictyonema floated freely in shallow and deep oceanic waters.
Other graptolite groups are very rare: the crustoids, tuboids, camaroids, and stolonoids.
Classification: Animalia, Hemichordata, Graptolithina, Dendroidea, Dendrograptidae
Stratigraphy: Rochester Shale, Niagaran Series (= Wenlockian), Middle Silurian
Locality: Middleport Quarry, town of Middleport northwestern New York State, USA
--------------------------
Info. at:
en.wikipedia.org/wiki/Graptolite
Tags: Desmograptus Rochester Shale Silurian Middleport Quarry New York State grapotlite graptolites Dendrograptidae Dendroidea dendroid dendroids fossil fossils carbonization carbonized compression compressions
Desmograptus sp. - dendroid graptolite from the Silurian of New York State, USA.
Graptolites are an extinct group of hemichordates that are most commonly preserved as carbonized compressions on shale bedding planes. They are typically not glamorous fossils, but they are critically important guide fossils and are widely used in biostratigraphy and for international correlation.
The most abundant group of graptolites in the fossil record is the graptoloids. Graptoloid graptolites typically resemble small hacksaw blades. Each “tooth” of the hacksaw blades housed a tentaculate, filter-feeding organism. The entire hacksaw blade is the graptolite skeleton, known as a rhabdosome - a nonmineralized colonial skeleton. Most graptolites were planktonic.
The second most abundant group of graptolites is the dendroids. Most dendroids attached to substrates and had colonial skeletons (rhabdosomes) that are generally broadly branching (conical to fan-shaped to shrub-like to flat spirals). A famous exception is Dictyonema, a planktonic dendroid that had a worldwide distribution. Dictyonema floated freely in shallow and deep oceanic waters.
Other graptolite groups are very rare: the crustoids, tuboids, camaroids, and stolonoids.
Classification: Animalia, Hemichordata, Graptolithina, Dendroidea, Dendrograptidae
Stratigraphy: Rochester Shale, Niagaran Series (= Wenlockian), Middle Silurian
Locality: Middleport Quarry, town of Middleport northwestern New York State, USA
--------------------------
Info. at:
en.wikipedia.org/wiki/Graptolite
Tags: Desmograptus Rochester Shale Silurian Middleport Quarry New York State grapotlite graptolites Dendrograptidae Dendroidea dendroid dendroids fossil fossils carbonization carbonized compression compressions