Paleontological investigations in the Ellsworth Mountains ...
References
Colbert, Edwin H., andJames W. Kitching. 1977. Triassic cynodont reptiles from Antarctica. American Museum Novitates, 2611 1-30. Estes, Richard. 1961. Cranial anatomy of the cynodorit reptile Thrinaxodon lzorhtnus. Bulletin of the Museum of Comparative Zoology, Harvard College, 125: 165-180, pls. 1, 2. Jenkins, Farish A., Jr. 1971. The postcranial skeleton of African cynodonts. Peabody Museum of Natural History, Bulletin, 36: i-x, 1-216.
Paleontological investigations in the Ellsworth Mountains, West Antarctica GERALD F. WEBERS
Department of Geology Macalester College St. Paul, Minnesota 55105 Antarctic faunas from the Heritage Range (centered at 79 0S. 85 0 W.) of the Ellsworth Mountains, including a new Late Cambrian trilobite fauna collected by a Norwegian expedition in the 1975-1976 austral season, have been under study. Despite the relatively small number of rock specimens collected, several new species are present. This fauna is stratigraphically close to a previously reported prolific trilobite-mollusk fauna (Webers, 1972) and promises additional fossil faunas in the thick (10,000 meters) stratigraphic
Steinkern of an antarctic Rostroconch, new genus and species, from the north central Heritage Range of the Ellsworth Mountains, 4X. 120
sequence exposed in the central and southern Heritage Range. The trilobite-mollusk fauna continues to yield important new forms. Calyx plates of unknown pelmatozoans have been recovered and represent at least two species. The fauna includes probably the best preserved and most diverse Late Cambrian mollusks known. Twenty species of mollusks are present representing the four molluscan classes: Monoplacophora, Hyolitha, Gastropoda, and Rostrochon chia. In addition, forms transitional to the Cephalopoda are present. -Monoplacophora are the dominant molluscan forms and are represented by several genera and 10 new species. Gastropoda are represented by four species referable to the Macluritacea. Hyolitha are represented by four species referable to Hyolithus, Contitheca, and Ort hot heca. Rostrochonchja are represented by two species referable to Riberta and to a new genus and mark the first antarctic occurrence of these forms. Protoconchs and early growth stages of various mollusks indicate some radical changes in shell shape during ontogeny and in some cases a complete reversal of shell curvature. The great diversity of mollusks along with a very diverse trilobite fauna and other faunal elements which include archaeocyathids, articulate and inarticulate brachiopods, and pelmatozoans, is indicative of a mild environment— probably tropical. The environment of deposition of the fauna appears to have been shallow marine and possibly littoral. The mollusks are the best preserved with protoconchs and early growth stages preserved. Archaeocyathids are invariably broken cylindrical forms only rarely preserving the early growth stages. Presumably they were broken from their attachments and transported to their resting sites. Trilobites are disarticulated predominantly adult stages and were probably also transported. The early growth stages as well as every other growth stage (with some forms as large as 8 centimeters) of the Monoplacophora, together with their excellent preservation, indicate that they dominated the shallow, nearshore environment, perhaps with a sprinkling of other faunal elements. There appears to have been a marked period of adaptive radiation for the mollusks in the Late Cambrian of Antarctica. The diversity of molluscan forms argues for adaption to a variety of life styles within the shallow water marine environment. Monoplacophorans probably include forms adapted to rock clinging and detritus feeding. One unusual monoplacophoran, Knightoconus antarcticus (Yochelson et al., 1973) is a precephalopod marking a direction toward pelagic capabilities. The various representatives of the Hyolitha perhaps also represent swimming forms. The presence of the Rostroconchia with their anterior and posterior siphons indicates an infaunal adaption (Runnegar and Pojeta, 1974). It thus appears that the Late Cambrian of West Antarctica marked a period of adaptive radiation of the mollusks. This rapid diversication appears to have occurred in tropical (perhaps littoral to sublittoral) environments. Somewhat later in the Late Cambrian this molluscan radiation is represented in the north-central United States. The diversity of forms is somewhat less, but the fauna still occupied the shallow marine littoral to sublittoral environment and lived under tropical conditions. This research was supported by National Science Foundation grant P3V-0036. ANTARCTIC JOURNAL
References
Runnegar, B., and J . Pojeta, Jr. 1974. Molluscan phylogeny: the paleontological viewpoint. Science, 186: 311-317. Webers, G.F. 1972. Unusual Upper Cambrian fauna from West Antarctica. Antarctic Geology and Geophysics. Universitetforlaget, Oslo, 235-237. Yochelson, EL., R.H. Flower, and G.F. Webers. 1973. The bearing of the new Late Cambrian monoplacophoran genus Knightoconus upon the origin of the Cephalopoda. Lethaza, 6: 275-310.
genera nonmarine dispersal routes between Africa, India and western Australia can account for the distribution. Cosmopolitan distribution of Mesozoic conchostracan genera in the southern continents including Antarctica is attributed to continental ligature or proximity. By contrast the conchostracan speciation program was restricted to local or regional situations (isolated lakes or ponds) (Tasch, in
press). This research was supported by National Science Foundation grant OPP 73-05831.
References
Intercontinental correlation by conchostracans and palynomorphs from Antarctica, western Australia, India, and Africa PAUL TASCH
Department of Geology Wichita State University Wichita, Kansas 67208 All three Tasch stations at Carapace Nunatak were found to have the components of Balme's Exesipollenites Assemblage from the Perth and Carnarvon Basins of western Australia (Jurassic, probably late Liassic). Excellent palynomorphs were recently recovered from a few Storm Peak samples (lower interbed, Tasch stations 0 and 1). Residues were good to massive. This contrasts with the general situation of palynomorph- barren beds in both lower and upper interbeds at Storm Peak, These new data will be reported by P. Tasch and J.M. Lammons at the Interna tional Palynological Colloquium, Leon, Spain in September 1977. A paper with T.J. Jones on the "Conchostracan fauna of the Carboniferous and Triassic of the Canning Basin" is being readied for publication by the Bureau of Mineral Resources (CS I RO, Canberra, Australia). Besides description of the fauna, findings suggest a post-Carboniferous dispersal of ribbed conchostracan eggs from Canning Basin of western Australia to the Bowen Basin and the Newcastle Coal Measures belt in eastern Australia. Permian ribbed conchostracans from the Ohio Range, have long since been shown to correlate with equivalents in the Newcastle Coal Measures. Correlation of nonmarine deposits of the Karroo System "Phyllopod Beds" (Northern Angola) and those of the Triassic Panchet Formation (Raniganj Basin, India) has been strengthened by discovery of three conchostracan genera common to both formations: Estheriina, Cornia, Paleolimnadia (Tasch and Oesterlen, 1977). Since the Triassic of the Canning Basin has species of two of these October 1977
Tasch, P. In press. Crustacean branchiopod distribution and speciation in Mesozoic lakes of the southern continents. In: Antarctic Research Series (B.C. Parker, ed.). Tasch, P., and P.M. Oesterlen. 1977. New data on the "Phyllopod Beds" (Karroo System) Northern Angola. South Central Geological Society America, Annual Meeting (El Paso). Abstracts with program: 77.
Palynomorph preservation in the Beacon Supergroup of the Transantarctic Mountains ROSEMARY A. KYLE
Institute of Polar Studies JAMES M. SCHOPF
Institute of Polar Studies and Department of Geology, The Ohio State University Columbus, Ohio 43210 Flat-lying sedimentary rocks of the Early Devonian to Earlyjurassic Beacon Supergroup occur throughout the Transantarctic Mountains. Several workers (e.g. Schopf, 1962; Norris, 1965; Helby and McElroy, 1969; Kemp, 1972; Kyle, in press) have experienced difficulty in extracting recognizable palynomorphs from Beacon rocks. The poor preservation or absence of palynomorphs is attributed to thermal metamorphism during the intrusion of the Jurassic Ferrar Group dolerite sills and extrusion of the comagmatic Kirkpatrick Basalt. This igneous activity has also resulted in the carbonization of plant cuticles and woody material, the semi-anthracite rank of the Permian and Triassic coal, and the formation of zeolites typical of low grade metamorphism. Over 500 samples from the Beacon Supergroup of the Transantarctic Mountains have been processed for palynological study. In some areas (e.g., southern Victoria Land and the Nilsen Plateau, Queen Maud Mountains) only 121
Colbert, Edwin H., andJames W. Kitching. 1977. Triassic cynodont reptiles from Antarctica. American Museum Novitates, 2611 1-30. Estes, Richard. 1961. Cranial anatomy of the cynodorit reptile Thrinaxodon lzorhtnus. Bulletin of the Museum of Comparative Zoology, Harvard College, 125: 165-180, pls. 1, 2. Jenkins, Farish A., Jr. 1971. The postcranial skeleton of African cynodonts. Peabody Museum of Natural History, Bulletin, 36: i-x, 1-216.
Paleontological investigations in the Ellsworth Mountains, West Antarctica GERALD F. WEBERS
Department of Geology Macalester College St. Paul, Minnesota 55105 Antarctic faunas from the Heritage Range (centered at 79 0S. 85 0 W.) of the Ellsworth Mountains, including a new Late Cambrian trilobite fauna collected by a Norwegian expedition in the 1975-1976 austral season, have been under study. Despite the relatively small number of rock specimens collected, several new species are present. This fauna is stratigraphically close to a previously reported prolific trilobite-mollusk fauna (Webers, 1972) and promises additional fossil faunas in the thick (10,000 meters) stratigraphic
Steinkern of an antarctic Rostroconch, new genus and species, from the north central Heritage Range of the Ellsworth Mountains, 4X. 120
sequence exposed in the central and southern Heritage Range. The trilobite-mollusk fauna continues to yield important new forms. Calyx plates of unknown pelmatozoans have been recovered and represent at least two species. The fauna includes probably the best preserved and most diverse Late Cambrian mollusks known. Twenty species of mollusks are present representing the four molluscan classes: Monoplacophora, Hyolitha, Gastropoda, and Rostrochon chia. In addition, forms transitional to the Cephalopoda are present. -Monoplacophora are the dominant molluscan forms and are represented by several genera and 10 new species. Gastropoda are represented by four species referable to the Macluritacea. Hyolitha are represented by four species referable to Hyolithus, Contitheca, and Ort hot heca. Rostrochonchja are represented by two species referable to Riberta and to a new genus and mark the first antarctic occurrence of these forms. Protoconchs and early growth stages of various mollusks indicate some radical changes in shell shape during ontogeny and in some cases a complete reversal of shell curvature. The great diversity of mollusks along with a very diverse trilobite fauna and other faunal elements which include archaeocyathids, articulate and inarticulate brachiopods, and pelmatozoans, is indicative of a mild environment— probably tropical. The environment of deposition of the fauna appears to have been shallow marine and possibly littoral. The mollusks are the best preserved with protoconchs and early growth stages preserved. Archaeocyathids are invariably broken cylindrical forms only rarely preserving the early growth stages. Presumably they were broken from their attachments and transported to their resting sites. Trilobites are disarticulated predominantly adult stages and were probably also transported. The early growth stages as well as every other growth stage (with some forms as large as 8 centimeters) of the Monoplacophora, together with their excellent preservation, indicate that they dominated the shallow, nearshore environment, perhaps with a sprinkling of other faunal elements. There appears to have been a marked period of adaptive radiation for the mollusks in the Late Cambrian of Antarctica. The diversity of molluscan forms argues for adaption to a variety of life styles within the shallow water marine environment. Monoplacophorans probably include forms adapted to rock clinging and detritus feeding. One unusual monoplacophoran, Knightoconus antarcticus (Yochelson et al., 1973) is a precephalopod marking a direction toward pelagic capabilities. The various representatives of the Hyolitha perhaps also represent swimming forms. The presence of the Rostroconchia with their anterior and posterior siphons indicates an infaunal adaption (Runnegar and Pojeta, 1974). It thus appears that the Late Cambrian of West Antarctica marked a period of adaptive radiation of the mollusks. This rapid diversication appears to have occurred in tropical (perhaps littoral to sublittoral) environments. Somewhat later in the Late Cambrian this molluscan radiation is represented in the north-central United States. The diversity of forms is somewhat less, but the fauna still occupied the shallow marine littoral to sublittoral environment and lived under tropical conditions. This research was supported by National Science Foundation grant P3V-0036. ANTARCTIC JOURNAL
References
Runnegar, B., and J . Pojeta, Jr. 1974. Molluscan phylogeny: the paleontological viewpoint. Science, 186: 311-317. Webers, G.F. 1972. Unusual Upper Cambrian fauna from West Antarctica. Antarctic Geology and Geophysics. Universitetforlaget, Oslo, 235-237. Yochelson, EL., R.H. Flower, and G.F. Webers. 1973. The bearing of the new Late Cambrian monoplacophoran genus Knightoconus upon the origin of the Cephalopoda. Lethaza, 6: 275-310.
genera nonmarine dispersal routes between Africa, India and western Australia can account for the distribution. Cosmopolitan distribution of Mesozoic conchostracan genera in the southern continents including Antarctica is attributed to continental ligature or proximity. By contrast the conchostracan speciation program was restricted to local or regional situations (isolated lakes or ponds) (Tasch, in
press). This research was supported by National Science Foundation grant OPP 73-05831.
References
Intercontinental correlation by conchostracans and palynomorphs from Antarctica, western Australia, India, and Africa PAUL TASCH
Department of Geology Wichita State University Wichita, Kansas 67208 All three Tasch stations at Carapace Nunatak were found to have the components of Balme's Exesipollenites Assemblage from the Perth and Carnarvon Basins of western Australia (Jurassic, probably late Liassic). Excellent palynomorphs were recently recovered from a few Storm Peak samples (lower interbed, Tasch stations 0 and 1). Residues were good to massive. This contrasts with the general situation of palynomorph- barren beds in both lower and upper interbeds at Storm Peak, These new data will be reported by P. Tasch and J.M. Lammons at the Interna tional Palynological Colloquium, Leon, Spain in September 1977. A paper with T.J. Jones on the "Conchostracan fauna of the Carboniferous and Triassic of the Canning Basin" is being readied for publication by the Bureau of Mineral Resources (CS I RO, Canberra, Australia). Besides description of the fauna, findings suggest a post-Carboniferous dispersal of ribbed conchostracan eggs from Canning Basin of western Australia to the Bowen Basin and the Newcastle Coal Measures belt in eastern Australia. Permian ribbed conchostracans from the Ohio Range, have long since been shown to correlate with equivalents in the Newcastle Coal Measures. Correlation of nonmarine deposits of the Karroo System "Phyllopod Beds" (Northern Angola) and those of the Triassic Panchet Formation (Raniganj Basin, India) has been strengthened by discovery of three conchostracan genera common to both formations: Estheriina, Cornia, Paleolimnadia (Tasch and Oesterlen, 1977). Since the Triassic of the Canning Basin has species of two of these October 1977
Tasch, P. In press. Crustacean branchiopod distribution and speciation in Mesozoic lakes of the southern continents. In: Antarctic Research Series (B.C. Parker, ed.). Tasch, P., and P.M. Oesterlen. 1977. New data on the "Phyllopod Beds" (Karroo System) Northern Angola. South Central Geological Society America, Annual Meeting (El Paso). Abstracts with program: 77.
Palynomorph preservation in the Beacon Supergroup of the Transantarctic Mountains ROSEMARY A. KYLE
Institute of Polar Studies JAMES M. SCHOPF
Institute of Polar Studies and Department of Geology, The Ohio State University Columbus, Ohio 43210 Flat-lying sedimentary rocks of the Early Devonian to Earlyjurassic Beacon Supergroup occur throughout the Transantarctic Mountains. Several workers (e.g. Schopf, 1962; Norris, 1965; Helby and McElroy, 1969; Kemp, 1972; Kyle, in press) have experienced difficulty in extracting recognizable palynomorphs from Beacon rocks. The poor preservation or absence of palynomorphs is attributed to thermal metamorphism during the intrusion of the Jurassic Ferrar Group dolerite sills and extrusion of the comagmatic Kirkpatrick Basalt. This igneous activity has also resulted in the carbonization of plant cuticles and woody material, the semi-anthracite rank of the Permian and Triassic coal, and the formation of zeolites typical of low grade metamorphism. Over 500 samples from the Beacon Supergroup of the Transantarctic Mountains have been processed for palynological study. In some areas (e.g., southern Victoria Land and the Nilsen Plateau, Queen Maud Mountains) only 121
