CATALOG OF ORIGINAL DESCRIPTIONS: Lithatractus timmsi Campbell & Clark 1944

This page provides data from the catalog of type descriptions. The catalog is sorted alphabetically. Use the current identification link to go back to the main database.

Higher levels: rads_cat -> L -> Lithatractus -> Lithatractus timmsi
Other pages this level: L. birostratus, L. carduelis, L. cirsium, L. conifer, L. conostylus, L. convallaria, L. echiniscus, L. floridus, L. fragilis, L. gamoporus, L. hederae, L. hexagonalis, L. jugatus, L. leptostylus, L. lobatus, L. miocaenica, L. nucleolus, L. nuphar, L. pachystylus, L. pierinae, L. pterosphaerus, L. rosetta, L. santaeannae, L. santaeannae pusillus, L. timmsi, L. timmsi quadrispinus

Lithatractus timmsi

Citation: Lithatractus timmsi Campbell & Clark 1944
Rank: species
Type specimens: pl.2, fig.18
Type repository: No holotype designated, slides at University of California, Museum of Paleontology
Described on page(s) : p.18
Family (traditional): Actinommidae
Family (modern): Stylosphaeridae

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Current identification/main database link: Lithatractus timmsi Campbell & Clark 1944

Original Description
Shell rather large, ovoidal, with two prominent, opposite, equal polar spines, which are long (1.23 times long axis of shell), strongly conical (5°), minutely blunted and irregular at tip as if subjected to pressure and compressed (perhaps points of attachment of protoplasmic strands), and swordlike, with four similar, triangular blades with sharp edges, and with bases merged separately on surface of cortical shell, blades at equal angles from each other in two crossed pairs (in our specimen one polar spine was broken off near base, but it is assumed to be duplicate of other); cortical shell generally egg-shaped, its longer axis (vertical axis, in line with polar spines) 1.13 times diameter of minor (transverse) axis, and with sides evenly contoured; medullary shell relatively large (its long axis 0.54 long axis of cortical shell), its transverse axis 0.85 diameter of long axis, and its sides regularly contoured to poles; radial supports (10?), two very strong, prismatic polar, four thinner radials, and four thin transverse, save polar ones, rodlike; pores of cortical shell subuniformly elliptical, only a few odd ones larger and of different form, shallow, narrowly double contoured, well spaced, and about 18 in long axis and 15 in transverse axis, of medullary shell about 10 in long axis and eight or nine in transverse axis, larger and more nearly squarish or subcircular than in cortical shell, deeper set and more widely separated; wall of cortical shell thicker than that of medullary shell; surface of cortical shell slightly roughened with short points.

Length, total (estimated on assumption that both polar spines are equal), 282µm, of polar spine, 99µm; diameter of pores of cortical shell, 4.4-6.6µm. Distinguishing characters (rw): Lithatractus timmsi n. sp. differs from pachystulus (Haeckel , 1887) in lack of funnel-shaped pores. In addition, it has much longer polar spines than latter, which is only other one of subgenus Lithatractara with tetrangular polar spines.

Editors' Notes


Campbell, A. S. & Clark, B. L. (1944a). Miocene radiolarian faunas from southern California. Geological Society of America, Special Papers. 51: 1-76. gs


Lithatractus timmsi compiled by the radiolaria@mikrotax project team viewed: 20-4-2021

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