This work was supported by National Science Foundation grant DPP 89-15439. The specimen upon which the description of the new species of Lyreidus was based was made available by M. R. A. Thomson, British Antarctic Survey, Cambridge, United Kingdom. (Contribution 526, Department of Geology, Kent State University, Kent, Ohio 44242.)
References
Feldmann, R. M. 1990. Decapod crustacean paleobiogeography: Resolving the problem of small sample size. In G. Mikulic (Ed.), Arthropod Paleobiogeography. Paleontological Society Short Courses inPaleontology, 3:303-315. Feldmann, R. M. 1992. The genus Lyreidus de Haan, 1839 (Crustacea, Decapoda, Raninidae): Systematics and biogeography. Journal of Paleontology, 66(6), in press. Feldmann, R. M. and P. A. Maxwell. 1990. Late Eocene decapod Crustacea from north Westland, South Island, New Zealand. Journal of Paleontology, 64: 779-797.
Fossil corals from Seymour Island, Antarctica HARRY F. FILKORN AND RODNEY
M. FELDMANN
Department of Geology Kent State University Kent, Ohio 44242
Fossil corals have been known to occur in the rocks on Seymour Island, Antarctica, since the early part of the century. Based upon specimens collected on Nordenskjöld's Swedish South Polar Expedition (1901-1903), Felix (1909) described six species of corals reported to have been collected from seven localities in Cretaceous rocks (Nordenskjöld's map in Andersson, 1906, pl. 6). Five of these localities were on Snow Hill Island, and two were on Seymour Island. With the exception of a preliminary report (Filkorn 1990), no subsequent examination of Cretaceous corals from this region has been made. During the austral summer of 1986-1987, M. A. Kooser, University of California, Riverside, California, and Rodney Feldmann documented the presence of corals at 24 localities on Seymour Island (figure 1), of which 18 were Cretaceous and six were Paleocene. Although these were anecdotal collections made while studying other macroinvertebrate taxa, over 400 specimens were collected. These specimens, as well as the original specimens studied by Felix, have served as the basis for a re-examination of the coral fauna of Seymour Island. Sixteen species of corals have been identified from Cretaceous and Paleocene rocks and referred to 13 genera. All the corals tend to be relatively small and all are presumed to have been azooxanthellate; that is, they lacked the algal symbionts that typify modern, shallow water reef building corals. Four of the 20
Feldmann, R. M., and M. 0. Woodburne, (Eds). 1988. Geology and paleontology of Seymour Island, Antarctic Peninsula. Geological Society of America Memoir, 169:566. Feldmann, R. M. and W. J. Zirismeister. 1984. New fossil crabs (Decapoda: Brachyura) from the La Meseta Formation (Eocene) of Antarctica: Paleogeographic and biogeographic implication. Journal of Paleontology, 58: 1046-1061. Glaessner, M. F. 1980. New Cretaceous and Tertiary crabs (Crustacea: Brachyura) from Australia and New Zealand. Transactions of the Royal Society of South Australia, 104:171-192. Sadler, P.M. 1988. Geometry and stratification of uppermost Cretaceous and Paleogene units on Seymour Island, northern Antarctic Peninsula. Feldmann, R. M. and M. 0. Woodbume (Eds.), Geology and Paleontology of Seymour Island, Antarctic Peninsula. Geological Society of America Memoir, 169:303-320. Zinsmeister, W. J. 1979. Biogeographic significance of the late Mesozoic and early Tertiary molluscan faunas of Seymour Island (Antarctic Peninsula) to the final breakup of Gondwanaland. In J. Gray and A. Boucot (Eds.), Historical Biogeography, Plate Tectonics and the Changing Environment. Proceedings of the 37th Annual Biology Colloquium and Selected Paper. Corvallis, Oregon: Oregon State University Press, 349-355.
species are colonial, forms whose skeletons formed branching, bush-like colonies, whereas the remainder are either free-living or attached, conical or cupolate, solitary forms. Within the collections made to date, the corals have been more widespread and diverse in the late Cretaceous to Paleocene Lopez de BertQdano Formation, where 12 solitary and one colonial species have been identified. In the Paleocene Sobral Formation, three colonial and one solitary species have been identified including one species of Madrepora that apparently formed relatively large thickets (figure 2). The species of solitary coral may be conspecific with one collected in the LOpez de Bertodano Formation. Tentatively three species have been recognized in collections from the Eocene La Meseta Formation; however, the paucity of corals in the La Meseta Formation is likely related to the intensity of collecting rather than to the abundance of or diversity of forms. Although the sampling of the rocks of Seymour Island for fossil corals s incomplete, the high diversity of the coral fauna, particularly ii the LOpez de Bertodano Formation, reinforces observations of high diversity in other invertebrate taxa collected from Seymour Island (see articles in Feldmann and Woodburn 1988). In general, the Cretaceous and Paleogene coral faunas on Seymour Island are dominated by taxa that have living descendants. The occurrences of five genera are unique to the James Ross Basin, four genera of corals within this assemblage represent the first occurrence of those genera in the fossil record, and at least eight species in five genera are ancestral to living forms that are inhabitants of lower latitude, deep-water assemblages. Thus, observations based upon corals from Seymour Island corroborate conclusions based on the study of arthropods, molluscs, and echinoderms (Zinsmeister and Feldmann 1984) that the southern high latitudes served as a site for origin of some modern deepwater species. Examination of the mineralogy of the coral skeletons, using a staining technique employing Feigi's solution (Feigl and Leitmeier 1933) and X-ray diffraction studies indicated that all specimens tested were composed of aragonite, the original skeletal mineralAr&icnc JOURNAL
sen ye
Surf icial deposits
IT'Ti
La Meseta : Tel
4-5
Formation Tel m3 Ic rn 1-2
!
Sobral Formation
Cross Valley Mbr. Tps I.
______ Tps?3 Ips3 Ips 1-2 KIt b 10
Lopez de Bertodano IU,
Lamb
K lb 1-9
Formation
Figure 1. Geologic map of Seymour Island denoting the sites (dots) from which fossil corals have been collected. Localities from which Felix's material was collected are indicated by squares. Base map from Sadler, 1988. ogy of the corallites. Unaltered aragonite in fossil material of late Cretaceous age is relatively rare. Its presence offers the opportunity of using corals for geochemical and isotopic analyses that may yield valuable information on paleobathymetry and paleotemperature. The results that have been derived from the preliminary collections made of fossil corals have documented a diverse fauna, largely of pioneering species, that have given rise to several modem taxa. Additional, more systematic collecting is warranted to fully document this unusual occurrence. Access to the type material of corals studied by Felix was provided by Christina Franzén-Bengtson, Nautrhistoriska Riksmuseet, Stockholm, Sweden. Field work for Feldmann was supported by National Science Foundation grant to William J. Zinsmeister. Laboratory work was partially supported by National Science Foundation grant DPP 89-15439. (Contribution 525, Department of Geology, Kent State University, Kent, Ohio 44242.) References Andersson, J . C. 1906. On the geology of Graham Land. Bulletin of the Geological Institute of Llpsala, 7:19-71, plates 1-6. Feldmann, R. M. and M. 0. Woodburne. 1988. Geology and Paleontology of Seymour Island, Antarctic Peninsula. Geological Society of America Memoir, 169:566. Feigi, F. and H. Leitmeier. 1933. Spot test for distinguishing between calcite and aragonite. Chemical Abstracts, 27(16): 3,896. Felix, J. 1909. Ober die fossilen Korallen der Snow Hill-Insel und der Seymour-Insel. Der Schwedishen Sudpolar-Expedition 1901-1903, Wissenschaftliche Ergebnisse, 3(5):1-15.
Filkom, H. F. 1990. Scieractinia from the Lopez de Bertodano and Sobral formations (Upper Cretaceous -Lower Tertiary), Seymour and Snow
1992 REVIEW
Figure 2. Fragments of Madrepora n. sp. littering an exposure of the Paleocene Sobral Formation on Seymour Island. The fossils are presumed to represent the remains of an azooxantheilate coral thicket. Hill Islands, Antarctic Peninsula, Antarctica. Geological Society of America, Abstracts with Programs, 22(5):10. Sadler, P. M. 1988. Geometry and stratification of uppermost Cretaceous and Paleogene units on Seymour Island, northern Antarctic Peninsula. In R. M. Feldmann and M. 0. Woodburne (Eds.), Geology and Paleontology of Seymour Island, Antarctic Peninsula. Geological Society of America Memoir, 169:303-320. Zinsmeister, W. J . and R. M. Feldmann. 1984. Cenozoic high latitude heterochroneity of Southern Hemisphere marine faunas. Science, 224:281-283.
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