Welcome to the Treatise on Invertebrate Paleontology!
Please enter a genera name to retrieve more information.
Stylostroma
Classification
Phylum:
Porifera
Class:
Stromatoporoidea
Order:
Labechiida
Superfamily:
Unknown
Family:
Stylostromatidae
Formal Genus Name and Reference:
Stylostroma GorSKy, 1938, p. 15
Type Species:
S. crassum; OD
Images
(Click to enlarge in a new window)
Fig. 402a–i. *S. crassum, southern shore of Melkaya Bay (loc. 401), Samolet Peninsula, probably upper Famen- nian, Novaya Zemlya, Russia; holotype, CNIGR, 5767/6; a–c, slide 5767/6b, low to high magni- fication longitudinal sections; a, X2; b, X5; c, X10; d–e, slide 5767/6c, longitudinal sections, X5; f–h, slide 5767/6a, low to high magnification sections; f, X2; g, X5; h, X10; i, topotype, tangential section, X5; this latter specimen was termed an autotopotype by gorSKy (1938), probably to signify its special significance as collected from the type locality by the original author of the species (Gorsky, 1938, p. 15, pl. 2,2–7, pl. 3,2).
Synonyms
Mamelolabechia
Geographic Distribution
Australia (Tasmania), China (Xinjiang), Norway, Sandbian–Katian; China (Guizhou), lower Silurian; Russia (Siberian platform), middle Silurian; Australia (northern Queensland), Lower Devonian; Canada (Alberta), China (Sichuan, Guizhou, Guangxi, ?Hunan), Kazakhstan, Russia (northern Caucasus, Novaya Zemlya, Urals, northeastern Siberia), Ukraine (Donets basin), Upper Devonian
Age Range
Beginning Stage in Treatise Usage:
Upper Ordovician (Sandbian)
Beginning International Stage:
Sandbian
Fraction Up In Beginning Stage:
0
Beginning Date:
458.18
Ending Stage in Treatise Usage:
Upper Devonian
Ending International Stage:
Famennian
Fraction Up In Ending Stage:
100
Ending Date:
359.3
Description
Skeleton mamelonate with pillars commonly restricted to mamelon columns, as simple, postlike, and upwardly and outwardly radiating, branching elements; pillars may be clus- tered in multibranched arrays, developing stellate or other less regular patterns tangentially, or may be more loosely interconnected where branching is more open and at less frequent intervals; denticles, or less commonly, short, unbranched, superposed pillars may occupy interspaces between columns; cyst plates commonly of small to moderate size and low convexity in regular cyst rows, but some- times more cystose and imbricated patterns occur, especially across interspaces. [The type species of Stylostroma (S. crassum) is characterized by having upwardly and outwardly radiating pillars that branch repeatedly within broad mamelon columns, giving an approximately stellate appearance of platelike forms where pillar branches remain fused toward the axis, but the pillars have a postlike form where unbranched, especially away from centers. S. tuberculata (yavorSKy) is at the other end of the range of morphological forms assigned to this genus. It shows more open and much less frequent branching in mamelon columns, and these pillars mainly exhibit postlike structures. A complete gradation of morphological forms exists between end members, here referred to as the S.crassum and S. tuberculata species groups. No clear-cut, age-related subdivision exists between the two morphological types: the simpler, mainly postlike S. tuberculata morphologies are not restricted to the Ordovician-Silurian record, nor are the more complexly fused S. crassum-type morphologies limited to the Late Devonian. Consequently, it remains preferable not to divide the genus into two, as favored by KHroMyKH (1977), with Mame lolabechia reserved for the Ordovician–Silurian species, and Stylostroma for the Late Devonian species. Additionally, a number of Chinese Ordo- vician species of Stylostroma have been retained in Pseudolabechia yaBe & SugiyaMa, 1930, by Dong and Wang (1984), and Dong (2001), but should be excluded from that genus, as the type species is an actinostromatid (see Mori, 1968, 1970; STocK in STearn & others, 1999; and see p. 771–776). Apart from some differences in preser- vation of the early forms, all the species of Stylos troma exhibit mamelon columns and pillars that branch and splay upward and outward from their centers, and cyst rows that range from long, low to imbricated, blisterlike profiles.]
References
Museum or Author Information
Classification
Phylum:
Porifera
Class:
Stromatoporoidea
Order:
Labechiida
Superfamily:
Unknown
Family:
Stylostromatidae
Formal Genus Name and Reference:
Stylostroma GorSKy, 1938, p. 15
Type Species:
S. crassum; OD
Images
(Click to enlarge in a new window)
Fig. 402a–i. *S. crassum, southern shore of Melkaya Bay (loc. 401), Samolet Peninsula, probably upper Famen- nian, Novaya Zemlya, Russia; holotype, CNIGR, 5767/6; a–c, slide 5767/6b, low to high magni- fication longitudinal sections; a, X2; b, X5; c, X10; d–e, slide 5767/6c, longitudinal sections, X5; f–h, slide 5767/6a, low to high magnification sections; f, X2; g, X5; h, X10; i, topotype, tangential section, X5; this latter specimen was termed an autotopotype by gorSKy (1938), probably to signify its special significance as collected from the type locality by the original author of the species (Gorsky, 1938, p. 15, pl. 2,2–7, pl. 3,2).
Synonyms
Mamelolabechia
Geographic Distribution
Australia (Tasmania), China (Xinjiang), Norway, Sandbian–Katian; China (Guizhou), lower Silurian; Russia (Siberian platform), middle Silurian; Australia (northern Queensland), Lower Devonian; Canada (Alberta), China (Sichuan, Guizhou, Guangxi, ?Hunan), Kazakhstan, Russia (northern Caucasus, Novaya Zemlya, Urals, northeastern Siberia), Ukraine (Donets basin), Upper Devonian
Age Range
Beginning Stage in Treatise Usage:
Upper Ordovician (Sandbian)
Beginning International Stage:
Sandbian
Fraction Up In Beginning Stage:
0
Beginning Date:
458.18
Ending Stage in Treatise Usage:
Upper Devonian
Ending International Stage:
Famennian
Fraction Up In Ending Stage:
100
Ending Date:
359.3
Description
Skeleton mamelonate with pillars commonly restricted to mamelon columns, as simple, postlike, and upwardly and outwardly radiating, branching elements; pillars may be clus- tered in multibranched arrays, developing stellate or other less regular patterns tangentially, or may be more loosely interconnected where branching is more open and at less frequent intervals; denticles, or less commonly, short, unbranched, superposed pillars may occupy interspaces between columns; cyst plates commonly of small to moderate size and low convexity in regular cyst rows, but some- times more cystose and imbricated patterns occur, especially across interspaces. [The type species of Stylostroma (S. crassum) is characterized by having upwardly and outwardly radiating pillars that branch repeatedly within broad mamelon columns, giving an approximately stellate appearance of platelike forms where pillar branches remain fused toward the axis, but the pillars have a postlike form where unbranched, especially away from centers. S. tuberculata (yavorSKy) is at the other end of the range of morphological forms assigned to this genus. It shows more open and much less frequent branching in mamelon columns, and these pillars mainly exhibit postlike structures. A complete gradation of morphological forms exists between end members, here referred to as the S.crassum and S. tuberculata species groups. No clear-cut, age-related subdivision exists between the two morphological types: the simpler, mainly postlike S. tuberculata morphologies are not restricted to the Ordovician-Silurian record, nor are the more complexly fused S. crassum-type morphologies limited to the Late Devonian. Consequently, it remains preferable not to divide the genus into two, as favored by KHroMyKH (1977), with Mame lolabechia reserved for the Ordovician–Silurian species, and Stylostroma for the Late Devonian species. Additionally, a number of Chinese Ordo- vician species of Stylostroma have been retained in Pseudolabechia yaBe & SugiyaMa, 1930, by Dong and Wang (1984), and Dong (2001), but should be excluded from that genus, as the type species is an actinostromatid (see Mori, 1968, 1970; STocK in STearn & others, 1999; and see p. 771–776). Apart from some differences in preser- vation of the early forms, all the species of Stylos troma exhibit mamelon columns and pillars that branch and splay upward and outward from their centers, and cyst rows that range from long, low to imbricated, blisterlike profiles.]