The type species of Coenites and Cladopora.   Figs. 1-3,  Coenites juniperinus Eichwald, Middle Silurian, Gotland.  Fig. 1 shows lunate apertures with septal ridges.   Figs. 2 is transverse section of the same specimen, showing thickened peripheral parts of corallites.  Fig. 3 is longitudinal section of same specimen showing axial and periaxial tabulae.  Figs. 4-6, Cladopora seriata Hall.   Fig. 4, exterior of hypotype showing smooth lunate apertures.  Fig. 5 is a tansverse section of the  same specimen showing thin-walled corallites.   Fig. 6 is longitudinal section of same specimen showing steeply inclined corallites

without tabulae.

Stumm (1960) distinguished these genera is a study of the type species.

 

COENITES

Coenites juniperius has an internal structure similar to that of dendroid species of Alveolites but differs in the arrangement of the septal ridges and in the peripheral thickening of the corallite walls. The type species of Alveolites,  A. suborbicularis Lamarck, has a single well-developed row of septal spines on the lower lips of the apertures and other rows of septal spines faintly developed in some corallites. In other species of Alveolites rows of septal spines are developed on both upper and lower lips of the apertures, and in still other species septal spines are absent.

 

CLADOPORA 

The genus Cladopora was described by James Hall (1851).  He included seven species, all from the "Niagara" limestone at Lockport, New York, and gave the following diagnosis for the genus: 

Ramose or reticulate; branches cylindrical or slightly compressed, terminations terete; coral composed of a series of tubes or cells radiating equally on all sides from the axis, and opening upon the surface in rounded or subangular expanded mouths; cells more or less closely arranged, but not always contiguous, and apparently destitute of septa or rays.  The corals of this genus form a very distinct and well characterized group, sometimes in masses of closely arranged, slender, parallel or branching stems, and in other species of beautiful reticulated forms. Where the cells are empty and well preserved, the openings on the surface are margined by a thin projecting lip or calicle on the lower side, having a nearly semicircular outline, and gradually sloping below into the substance of the branch. In worn specimens the surface has no prominences, and the apertures of the cells are subangular or rounded, being a little more expanded than the cavity below.  Where the cells are filled with calcareous matter, they frequently separate in prismatic forms like Favosites, but there is no evidence of transverse septa.  The cells are not always contiguous, and there is often a space between the walls, which appears to be solid in one or more species.  These corals belong apparently to a group, some species of which have been referred to Alveolites by different authors, but which do not possess the essential characters of that genus; neither do they belong to the genus Chaetetes or Favosites.  All the species yet known are branching, the reticulated forms being produced by coalescing of the branches, which, at the extremities, are often free or ramose.  Probably some of the smaller reticulated species have been referred to Retepora, from which they are readily distinguished by the branches being poriferous on all sides, as well as in the form of the cell.

Lang, Smith, and Thomas, in their Index to Palaeozoic Coral Genera (1940), stated that C. seriata is a species of Coenites. This opinion was concurred in by Shimer and Shrock (1944), but Lecompte (1939) maintained that Coenites and Cladopora were not congeneric. He described the internal structures of C. sedata.  

Stumm's (1960) study of the internal structures of Cladopora seriata and of Coenites juniperinus, the type species of Coenites, confirmed Lecompte's contention that the two species are distinct and that Cladopora is a valid genus.

Cladopora seriata was described by Stumm as: corallum dendroid or phaceloid, composed of cylindrical stems averaging about 2 mm. in diameter. Stems composed of obliquely directed corallites diverging at a very steep angle from the axis. Corallites gradually expanding toward periphery, with a maximum diameter of 0.5 mm. and a length of 2 to 3 mm. Apertures sublunate or lozenge-shaped, with a slightly projecting lower lip. No septa1 ridges or spines present in apertures. Mural pores relatively large, irregularly scattered. No tabulae present.

Distribution of Cladopora (according to the Palaeobiology database ( http://www.paleodb.org/cgi-bin/bridge.pl?action=basicTaxonInfo&taxon_no=4840 ) is:

Distribution:

• Permian of United States (1: New Mexico collection)

• Couvinien of Australia (1)

• Devonian of Australia (19), Canada (2: Ontario), China (10), France (1), Germany (2), Mongolia (2), New Zealand (5), Poland (1), the Russian Federation (12), Spain (4), Tajikistan (5), Thailand (4), United States (39: Alaska, Indiana, Kentucky, Nevada, New Jersey, New York, Ohio), Vietnam (11)

• Silurian to Devonian of Australia (1), Pakistan (1)

• Silurian of Australia (3), Canada (7: Quebec), China (4), Estonia (1), Mongolia (3), the Russian Federation (6), Ukraine (5), the United Kingdom (1), United States (18: California, Kentucky, New York, Pennsylvania)

For example (Garra Formation) -

J. R. Farrell. 1992. The Garra Formation (Early Devonian: Late Lochkovian) between Cumnock and Larras Lee, New South Wales, Australia: stratigraphic and structural setting, faunas, and community sequence. Palaeontographica Abteilung A 222(1-3):1-41

STRIATOPORA 

 

Striatopora differs in having tabulae and septal ridges.   Sides of calyx walls are provided with 12 low, broad septa1 ridges.  Also, as in many other Devonian branching tabulate corals, the walls may thicken outwards.

 

 

In "Oliver W.A., 1966.   Description of dimorphism in Striatopora flexuosa Hall.   Palaeontology, vol. 9, pt. 3, pp. 448-454."

 

Oliver (1966) discussed some of the similar genera thus:

 

 

 

THAMNOPORA

In a typical Thamnopora as described by Stumm (1961), Thamnopora alpenensis (Rorninger), the features are:  Corallum dendroid, stems branching dichotomously, stems typically round, but may be elliptical in parts of corallum, especially at junctions. Stem ranging from 1 to 2 cm in diameter. Apertures subround to oval or lunate, averaging about 0.8 mm in diameter and opening at an angle of 25 to 30 degrees to the periphery. Thickness of peripheral parts of walls ranging from 0.1 5 mm to 0.9 mm, averaging 0.5 mm. In transverse section axial parts of corallites thin-walled, periaxial, and peripheral parts becoming progressively thicker. In longitudinal section corallites ascending at about 80 degrees to the periphery, tabulae thin, complete, irregularly spaced, 0.4 mm to 1.5 mm apart, and discernible in axial part of corallite only. Mural pores uniserial, round, averaging about 0.2 mm in diameter, irregularly spaced.

. 

Part of a large corallum of Thamnopora or Cladopora in the Lake Bathurst Limestone Member.  (Photo: Owen Thomas)

Cladopora bifurca   ( http://www.fossils-japan.com/img/cladopora_12.jpg )

Cladopora bifurca  Rockpot Quarry Limestone
Location:  Alpena, Michigan

The Limestones and limey shales contained large numbers of predominantly a tabulate coral known as Thamnopora. (Earlier publications called them "Cladopora").  This beautiful branching coral formed huge colonies and sub reefs on the open sea floor.  While this locality is not technically a reef, it is a rich assembly of low diversity shallow water fauna. ("Thatcoensis").   -  http://www.schursastrophotography.com/paleo/formations/martin.html

The small dimensioned Silurian Cladopora spp. are fairly easily diagnosed.

Coming into the Devonian the Cladopora spp. of  larger dimensions may converge in resemblance with Thamnopora spp. etc.

A good paper to see the differences from is:

Title:	Corals of the Travers Group of Michigan Part VI, Cladopora, Striatopora, and Thamnopora
Authors:	Stumm, E. C.
Issue Date:	1961
Publisher:	Museum of Paleontology, The University of Michigan
Citation:	Vol. 16, No. 4   http://hdl.handle.net/2027.42/48348