Mastigograptus tenuiramosus

Classification
Phylum: Hemichordata
Class: Graptolithina
Order: Mastigograptida
Family: Mastigograptidae
Genus: Mastigograptus
Species: Mastigograptus tenuiramosus (Walcott, 1881)

Stratigraphic Occurrences

M.tenuiramosus

Geographic Occurrences

Map point data provided by iDigBio.

Stratigraphic Description

Sequences (Formations)

  • C4 Sequence (Arnheim?)
  • C1 Sequence (Clays Ferry/Kope: McMicken, Economy/Fulton)

Identification in Hand Sample

  • Stipe slender, compressed; branches bifurcate from it irregularly, frequently subdividing, terminating in filiform extremities
  • Celluliferous side with smooth simple round pits, or depressions, along the center of the branches
  • Rhabdosome forming a densely branched bush attaining a size of 20+cm; the branches extremely slender, especially in their long distal portions
  • The branches are filiform, smooth, as a rule retaining but central row of circular pits (about 2.2 mm apart from each other), apparently only on one side of the branch
  • Rows of long conical pedunculate, obliquely ascending appendages, 1.2-1.5 mm long, are observed bearing on their pedunculate bases pairs of similarly shaped, usually shorter and slightly inward curved opposite cones

Mastigograptus tenuiramosus from the Arnheim Formation of Mt. Orab, Ohio (OUIP 1178)

Published Description

Fossils of Ohio (1996):

  • Another species, M. tenuiramosus has been collected from the Kope Formation at several localities in the Cincinnati region, and a similar form occurs in the Arnheim Formation at Stonelick State Park in Clermont County. The rhabdosome of these forms may reach a size of 200mm and exhibits a simpler (mostly dichotomous) type of branching than the two former species (M.strictus, M.perexilis)

Ruedemann (1908):

  • Stipe slender, compressed; branches bifurcate from it irregularly, frequently subdividing, terminating in filiform extremities; surface apparently smooth. Celluliferous side with smooth simple round pits, or depressions, along the center of the branches. Substance corneous and as in Dendrograptus simplex probably tubular. The compression of the tubular stipe and branches forms a rim-like margin on each side of a central depressed area in which the cellules are seen…
  • Description: Rhabdosome forming a densely branched bush attaining a size of 20+cm; the branches extremely slender, especially in their long distal portions (.3mm average width), given off monodially and alternating at small, somewhat irregular intervals (1.5mm at an average) and at an angle of 50 degrees.; this rather large angle giving the bushes a characteristic shrubby appearance in the central parts, while the distal parts are inclined to become pendant. The branches are filiform, smooth, as a rule retaining but central row of circular pits (about 2.2 mm apart from each other), apparently only on one side of the branch. When perfectly preserved, rows of long conical pedunculate, obliquely ascending appendages, 1.2-1.5 mm long, are observed bearing on their pedunculate bases pairs of similarly shaped, usually shorter and slightly inward curved opposite cones.