Mastigograptus

Classification
Phylum: Hemichordata
Class: Graptolithina
Order: Mastigograptida
Family: Mastigograptidae
Genus: Mastigograptus Ruedemann, 1908
Cincinnatian Species: Mastigograptus tenuiramosus

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Geologic Range
Cambrian – Ordovician, ?Silurian

Common Paleoecology
Mastigograptus is an extinct genus of passively mobile planktonic suspension feeders

Identification in Hand Sample:

Dendroid rhabdosomes, very thin
Lacks projecting thecae
Irregularly developed conical thecae (resembling a string of bells)
Stems and branches possess a strong tendency to become, each independently, enrolled
Thecae apertures are seen as fine circular pits, numbering nine to eleven in the space of 10 mm

Geographic Occurrences

Species Differentiation

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Holland (UGA Strat Lab, 2013):

Slender, dendroid rhabdosomes; lacks projecting thecae

Fossils of Ohio (1996):

The rhabdosome branches of this species are very thin (.05-1m)

Treatise on Invertebrate Paleontology, Part V (1955):

Slender dendroid rhabdosomes with rather irregularly developed conical thecae.

Ruedemann (1908):

Original description.-Rhabdosome small, consisting of very thin (0.2 mm.) filiform extremely flexuous stem and equally flexuous, still thinner alternating branches dividing repeatedly
into long branches of higher orders, the process of subdivision continuing until almost invisible, long hairlike branches result. Stems and branches possess a strong tendency to become, each independently, enrolled. Thecae apertures are seen as fine circular pits, numbering nine to eleven in the space of 10 mm.

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M. tenuiramosus