- Tytuł:
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Complexastraea i Thecosmilia z astartu Polski
Complexastraea and Thecosmilia from the astartian of Poland
Complexastraea i Thecosmilia iz astarta Polshi - Autorzy:
- Roniewicz, E.
- Powiązania:
- https://bibliotekanauki.pl/articles/22459.pdf
- Data publikacji:
- 1960
- Wydawca:
- Polska Akademia Nauk. Instytut Paleobiologii PAN
- Opis:
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Opracowano kilka gatunków korali należących do rodziny Montlivaultiidae Dietrich, zebranych w górnej jurze obrzeżenia Gór Świętokrzyskich.
Okazy z Bukowej pochodzą ze środkowego astartu, a okazy z Sobkowa, Sulejowa i okolic Kodrąbia - z górnego astartu. Opisano 6 gatunków korali ,w tym 2 nowe :
Complexastraea sobkoviensis n. sp. i C. carinata n. sp.
Description is here made of several corals of the family Montlivaultiidae Dietrich, collected in 1957 and 1959 from Upper Jurassie limestones outcropping in the western and north-western margins of the Holy Cross Mountains (Góry Świętokrzyskie). Specimens collected at Bukowa are referable to the Middle Astartian, those from exposures at Sobków, Sulejów on the Pilica and the vicinity of Kodrąb - to the Upper Astartian. Six coral species are described , two of them are new to science. Within the marginal area of the Holy Cross Mountains corals occur foremost in Middle and Upper Astartian beds, mainly in detritic limestones bunt of organic remains and of oolithic limestones, with a large admixture of organogenic clastic material. They are mostly colonial corals, branched or massive. In the sediment they occupy a life position and bear traces of organic destruction only. Frequently corals are associated with large molluscs and gastropods. On the whole they do not form major accumulations. In pelitic compact limestones corals occur less frequently than in oolithic and detritic limestones. They aro represented mostly by species with massive colonies smaller than those of corals in oolithic limestones. The colonies here described come from both mentioned varieties of limestone. Thecosmilia trichotoma (Goldf.) and Complexastraea hemisphaerica Geyer have been recovered from oolithic unbedded limestones in quarries within the Kodrąb area . Fossils associated with them are listed on p. 452/3 of the Polish text. Complexastraea thevenini (Et.) occurs in the quarry at Bukowa, in compact cream-coloured limestones, along with scarce molluscs and gastropods, also with indeterminate colonial and individual corals. C. burgundiae (Blainv.) has been recorded from detritic limestones at Sulejów on the Pilica. It occurs there in association with a rich fauna listed on p. 452/3 of the Polish text. Colonies of two new species - Complexastraea sobkoviensis and C. carinata have been found in the products of weathering of oolithic limestones in the vicinity of Sobków. The environmental conditions of the here considered corals may be interpreted as not being a true reef, but rather an accumulation of organisms within a moderately shallow neritic zone, not very distant from the shore. Genus Complexastraea d'Orbigny, 1849 Specific identifications within this genus will be facilitated not only by such features as size of the corallite diameter , number of septa etc., but also by the following structural characters of the endotheca, thus far not sufficiently taken into account : 1. Relative development of endothecal elements . In C. hemisphaerica Geyer we may observe strong development of the dissepiments; in C.thevenini (Et.), C. sobkovicnsis n. sp . and C. carinata n. sp. the dissepiments are less numerous and more flat , pseudotabulae being the predominant elemen t. In C. burgundiae (Blainv.) regularly arranged, broad pseudotabulae predominate, the vesicles are few. 2. Varying density of elements. In C. thevenini (Et.) and C. carinata n. sp . the endotheca is dense, made up of extremely flat and thin elements. 10-11 pseudotabulae fit into 1 mm in longitudinal section; in the remaining species the endotheca consists of large and fairly thick elements, loosely arranged, with 5-7 pseudotabulae in 1 mm. 3. Arrangement pattern. The axial depression on the endotheca varies: it is shallowest in C. carinata n. sp., deepest in C. burgundiae (Blainv.) and intermediate in the remaining species, The arrangement pattern of transverse elements between corallites depends on the distance separating the corall it es. In C. thevenini (Et .), C. hemisphaerica Geyer, C. sobkoviensis n. sp . and C. carinata n. sp. the corallites are rather closely arranged, hence the costal part of septae is poorly developed and the Jines of divergence of contacting septa are markedly close. Since the greatcst elevation of endothecal elements occurs along the passage or the line of divergence, the transversal elements between two corallites are convex, rounded or flattened at the top, and occasionally slightly concave. In C. burgundiae (Blainv.) the corallites are not so closely spaced, the costal part of septa is well developed, the lines of divergence of the contacting septa being, therefore, far spaced. Hence the greatest elevations of pseudotabulae occur at some distance from one another with a broad and deep depression in between them. The only mode of budding observed by the writer in species of the genus Complexastraea d'Orbigny is intracalicinal, shown in C. thevenini (pl. VIII). Microstructure of septa, stereom and dissepiments is unrecognizable due to the recrystallization of skeleton. The only vestige of primary structure, visible in slides of septa, is a light median line, about 0.03 mm wide, bordered from each side with one thin, dark line. Complexastraea sobkoviensis n. sp. (pl, VI ) Diagnosis. - Massive colony, up to 40 cm in height. Corallites ovoid in cross section, with diameter ranging f rom 1.1 X 1.6 cm to 1.2 X 2.0 cm. Distance between centres of corallites varies from 1.3 to 1.8 cm. The thirty-four to fourty -seven septa are thin, ornamented by notably small carinae. Endotheca consists of pseudotabulae, centrally flatly arranged, five fitting on 5 mm in cross section, and of large vesicular dissepiments. Between corallites these form an elevation with flattened top. Comparison. - This species, with diameter similar to that in C. hemisphaerica Geyer and C. carinata n. sp., differs from them in number of septa and structure of endotheca. Endotheca consists of widely spaced central pseudotabulae and of large vesicular dissepiments. From other known species it differs in smaller corallites and in number of septa. Complexastraea carinata n. sp. (pl. VII) Diagnosis. - Tabular colony. In cross section corallites ovoid or round, with diameter up to 1.5X2.0 cm. Distance between centres of corallites from 1.3 to 1.8 cm . Septa (40-56) rather densely spaced, ornamented by protruding carinae. Major and minor septa somewhat more dilated than the remaining ones. Endotheca consisting of thin pseudotabulae and dissepiments. In the centre of corallites these are slightly depressed , while in between the corallites they form an elevation with concave top. 10- 11 pseudotabulae occur on 5 mm in longitudinal section. Comparison . - In size of corallites this species resembles C.hemisphaerica Geyer and C. sobkoviensis n. sp. It differs therefrom in number of septa, their more conspicuous ornamentation and in structure of endotheca consistlng of very densely arranged pseudotabulae and flat dissepiments. In structure of endotheca it approaches C. thevenini (Et .), but it is with smaller corallites and more distinctly marked ornamentation of septa. From the remaining species it differs foremost in smaller dimensions of corallites. - Źródło:
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Acta Palaeontologica Polonica; 1960, 05, 4
0567-7920 - Pojawia się w:
- Acta Palaeontologica Polonica
- Dostawca treści:
- Biblioteka Nauki
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