Werner Piller

Benthic foraminiferal associations in the Northern Bay of Safaga, Red Sea, Egypt

Abstract In the shallow-water area (0–70 m) of the Northern Bay of Safaga, 73 surface samples were studied with respect to total foraminiferal fauna. The samples cover a great variety of shallow-water environments and yielded 239 foraminiferal taxa. Based on q-mode cluster analysis, and tested by canonical discriminant analysis, the samples are grouped into 13 foraminiferal associations, each characterized by several species: (1) Quinqueloculina mosharrafai-Borelis schlumbergeri-Brizalina simpsoni Ass., (2) Heterostegina depressa-Amphlstegina lessonii/bicirculata Ass., (3) Cibicidids- Rosalina-Amphistegina lobifera-Pseudoschlumbergerina ovata Ass., (4) Peneroplis planatus Ass., (5) Peneroplis planatus-Varidentella neostriatula Ass., (6) Peneroplis planatus-Coscinospira hemprichii-Varidentella neostriatula Ass., (7) Quinqueloculina spp. Ass., (8) Hauerina diversa-Sorites orbiculus Ass., (9) Verneuilina sp.-n Articulina pacifica-Reussella simplex Ass., (10) Textularia agglutinans/rugulosa-Bolivina variabilis Ass., (11) Textularia agglutinans-Challengerella bradyi-Elphidium jenseni/simplex Ass., (12) Operculina ammonoides-Adelosina laevigata-Brizalina striatula/subspathulata Ass., (13) Bolivina variabilis—Miliolinella-Nonion fabum-Elphidium simplex Ass. The characteristic forms of each association are linked to specific environmental parameters and modes of life. As long as taxonomic uniformitarianism can be applied, similar associations with comparable ecological demands may also be detected in the fossil record. For comparisons with taxonomically different material the 13 associations are summarized into 4 categories each reflecting a specific type of substrate. In the fossil record these categories may be recognized by general morphological characteristics of the foraminiferal tests and by sedimentological data. The 4 substrate types are: hardground, sand (with or without seagrass and/or corals), firmground, and soft bottom.

Distribution and environmental control of coral assemblages in northern Safaga Bay (Red Sea, Egypt)

SummaryCoral assemblages in northern Safaga Bay, Red Sea, Egypt, are qualitatively described. Nine distinct assemblages were found, which correspond to quantitatively defined community types previously described from the area off Hurghada, northern Red Sea. Their distribution within northern Safaga Bay was mapped. Strong gradient and/or steep relief assemblages were:Acropora assemblage on windward (exposed) reefs,Porites assemblage on leeward (sheltered) reefs,Millepora assemblage on current exposed reefs,Stylophora assemblage on reef flats. Low gradient and/or low relief assemblages were:Acropora dominated coral patches in areas of good circulation to a depth of 15 m,Stylophora/Acropora coral patch assemblages in shallow sheltered environments, faviid carpet in low relief areas between 10 and 25 m which with increasing turbidity turns into a depauperate faviid carpet,Porites carpet in low relief areas between 5 and 15 m with clearest water,Sarcophyton carpet in low relief areas with high suspension load, platy scleractinian assemblage in deeper water (>25 m) with low light intensity. The distribution of coral assemblages depends basically on 1) topography 2) hydrodynamics 3) light and 4) suspension load.

Sequence variations in the large-subunit ribosomal RNA gene of ammonia (foraminifera, protozoa) and their evolutionary implications

An unusually high divergence was observed in the ribosomal RNA genes of a free-living population of foraminifera belonging to the genusAmmonia. The sequences of a large-subunit (LSU) rDNA expansion segment D1 and flanking regions were obtained from 20 specimens namedAmmonia sp. 1 andAmmonia sp. 2. The sequence divergence between the two species averages 14%. Within each species it ranges from 0.2% to 7.1% inAmmonia sp. 1 and from 0.7% to 2.3% inAmmonia sp. 2. We did not find two specimens having identical sequences. Moreover, in opposition to the generally acaepted view, rDNA sequence variations were also found within a single individual. The variations among several rDNA copies in a single specimen ofAmmonia may reach up to 4.9%. Most of the observed variations result from multiplication of CA or TA serial repeats occurring in two particularly variable regions. For single base changes, C-T transitions are most frequently observed. We discuss the evolution of expansion segments and their use for phylogenetic studies.

Ökologie und systematische stellung der foraminiferen im gebankten dachsteinkalk (obertrias) des nördlichen toten gebirges (oberösterreich)

Zusammenfassung Statistical analysis reveals the strong facies dependence of foraminifera of the backreef environment in the Upper Triassic sedimentary limestones. Six facies are distinguished on the basis of counted allochems: 1. (1) Oolite facies. Ooids indicate strong water turbulence and normal marine salinity. Vagile foraminifera with great adherence dominate (Tetrataxis, Duostomina, etc.). Glomospirella indicate the allochthonous position of ooids. 2. (2) Oolitic facies. Ooids have been transported and redeposited. The heterogeneous composition of foraminifera reflects the close association with the oolite, grapestone and pellet-mud facies. 3. (3) Grapestone facies. Subtidal algal mats and strong water turbulence caused the formation of grapestones. The sligjtly raised salinity affords optimum conditions for vagile miliolids (Miliolipora, Quinqueloculina). 4. (4) Calcareous algal-foraminiferal-detritus facies. Undamaged Dasycladaceae indicate low turbulence. Salinity may have reached higher levels in which highly variable involutinids with big shells were developed. Their association with calcareous algae corresponds to that of Recent larger foraminifera. 5. (5) Pellet-mud facies. Pellets and micritic matrix indicate the least water movement and high salinity. Strongly adapted foraminifera, such as Trochammina, Agathammina, Palaeospiroplectammina and Frondicularia, predominate. 6. (6) Mud facies. The absence of pellets, because of their destruction, confirms stronger water currents than in the pellet—mud facies; salinity reaches high levels. Foraminifera with thin shells (Involutina, Nodosaria) preferred this environment. Because of the different structure of shells, which is most clearly demonstrated by diagenesis, some genera had to be regrouped in their systematic position (e.g., Agathammina had to be grouped among Textulariida).

Reassessment of Palaeothamnium Conti, 1946 (Corallinales, Rhodophyta)

Palaeothamnium has been identified in many algal associations from the Late Cretaceous to the Miocene since its definition by Conti (1946b). Revision of Contis original collection and of new material from the type localities in the Vienna Basin indicate that the developmental stages of the conceptacles of the type species P. archaeotypum are common in many other present-day and fossil coralline algae belonging to different genera of the subfamily Melobesioideae and therefore cannot be considered a diagnostic generic character. The presence of flat epithallial cells and long subepithallial initials together with a well-developed peripheral region in the type species leads us to consider Palaeothamnium as a younger heterotypic synonym of Lithothamnion Heydrich, 1897. However, according to modern melobesioid taxonomy, its attribution to Synarthrophyton Townsend, 1979 cannot be completely excluded. In addition, the type species of Palaeothamnium must be treated as a younger heterotypic synonym of Lithothamnion ramosissimum (Reuss, 1847) Piller, 1994.

Molecular versus morphologic variability in Ammonia SPP. Foraminifera, Protozoa) from the Lagoon of Venice, Italy

The genus Ammonia is one of the most common benthic foraminifer of considerable biogeographic importance. The taxonomic status of most of the described species of Ammonia, however, is yet unsettled. In the present study, we used the partial large subunit ribosomal DNA (LSU rDNA) sequences as an alternative approach to distinguish different specimens of Ammonia living in the Lagoon of Venice. We have obtained DNA sequences from 20 living specimens whose tests were examined previously by scanning electron microscopy (SEM). Sequence analysis revealed the presence of two groups, which differ by more than 10.5%. Within each group, the sequence divergence ranges from 0.2 % to 6.9 %. The two groups that can be separated genetically, are called Ammonia sp. 1 and Ammonia sp. 2. Their morphological distinction, however, is problematic. The tests of Ammonia sp. 1 are generally characterized by a more lobate periphery, more elevated dorsal sutures and larger perforations compared to those of Ammonia sp. 2, but none of these characters can be used with certainty for the morphological distinction of both groups.

Wall Structures of Palaeotextulariid Foraminifers and Discussion of Microgranular Test Walls

Investigations of the test wall structures of Upper Palaeozoic Palaeobigenerina geyeri and other palaeotextulariid foraminifers revealed that the outer layer of the wall, previously interpreted as being microgranular, is agglutinated. The inner layer is composed of equidimensional, rhombohedral crystals apparently arranged in elements perpendicular to the wall surface, which resembles hyaline radial test walls in structure. The walls are perforate and the pores are branched. A comparison of microgranular and agglutinated test walls shows that their distinction seems very artificial and that a reinvestigation is required.