Marine Invertebrate Fauna Research Articles

Timing and warmth of the Last Interglacial period: new U-series evidence from Hawaii and Bermuda and a new fossil compilation for North America

The timing and duration of the Last Interglacial period have been controversial, with some studies suggesting a relatively short duration that is orbitally forced and others suggesting a long duration that is at most only partly related to orbital forcing. New, high-precison thermal ionization mass spectrometric (TIMS) U-series ages of Last Interglacial corals from Hawaii and Bermuda test these competing hypotheses. Waimanalo Formation corals from slowly uplifting Oahu, Hawaii range in age from ∼134 to ∼113 ka, with most ages between ∼125 and ∼115 ka. Combined with published U-series ages from nearby Lanai, the data suggest a long Last Interglacial period that may have occurred from ∼136 to at least 115 ka. The results indicate that orbital forcing may not have been the only control on ice sheet growth and decay, because sea level would have been high at times of relatively low Northern Hemisphere summer insolation. On tectonically stable Bermuda, deposits from the ∼200 ka (penultimate interglacial period), ∼120 ka (peak Last Interglacial period) and ∼80 ka (late Last Interglacial period) high sea stands have been newly dated. Fossil corals on Bermuda are derived from patch reefs that likely were “catch-up” responses to sea level rise. It is expected that U-series ages of Last-Interglacial corals on Bermuda should overlap with, but not be as old as the range of corals on Oahu. Last-Interglacial corals on Bermuda give a range of ∼125–113 ka, which supports this hypothesis. A large number of emergent marine deposits on Hawaii, Bermuda and along coastal North America have now been dated to the Last Interglacial period. Both Oahu and Bermuda have marine invertebrate faunas with a number of extralimital southern species of mollusks, suggesting warmer-than-present waters during the Last Interglacial period. Warmer waters are also suggested for Last-Interglacial localities around most of North America, from Florida to Canada and Greenland and Baja California to Alaska. These observations are consistent with similar warm-water faunas of Last-Interglacial age reported from Japan, the Mediterranean basin and Western Australia. It is likely that significant changes in ocean currents took place during the Last Interglacial period, with a movement of relatively warm waters to higher latitudes than is the case today.

First Record of Baseodiscus hemprichii (Nemertea: Baseodiscidae) on Easter Island (Rapa Nui) and a New Eastern Distribution Boundary for the Species

A single specimen of the nemertean Baseodiscus hemprichii (Ehrenberg, 1831) was collected from Easter Island during August 1999. This represents the ®rst record of the species on Easter Island, the ®rst identi®ed nemertean from that island, and extends the eastern boundary of the species' range by approximately 4800 km. The small South Paci®c landmass of Easter Island, or Rapa Nui, is situated nearly 3800 km from the South American mainland and over 2200 km from Pitcairn Island, its nearest neighbor to the west. All of the marine fauna shows af®nities to the Indo-Paci®c, although the water temperatures of 17.5± 24 C are relatively cool (DiSalvo et al. 1988). All available data indicate that the marine invertebrate fauna of Easter Island is depauperate compared with other islands of the tropical Paci®c (Rehder 1980, Massin 1996), but it has a high percentage of endemic taxa (e.g., 36% for Mollusca, 39% for Porifera [unpubl. data]). It is therefore considered its own biogeographic province along with tiny Sala y GoÂmez, 415 km to the east (Briggs 1974). On Easter Island, however, specimens of only eight invertebrate phyla have been identi®ed to the species level to date. A single specimen of nemertean was collected during August 1999 as part of an invertebrate survey of Easter Island. It was subsequently readily identi®ed as Baseodiscus hemprichii (Ehrenberg, 1831) on the basis of its distinctive color pattern. This represents not only the ®rst record of the species on Easter Island, but extends the eastern boundary of the species' range by approximately 4800 km. Although nemerteans have been recorded as occurring on Easter Island (DiSalvo et al. 1988), this is the ®rst identi®cation of any specimen to the species level. The specimen is deposited in the American Museum of Natural History, New York (amnh). Family Baseodiscidae Bu .. rger, 1907 Genus Baseodiscus Diesing, 1850 Baseodiscus hemprichii (Ehrenberg, 1831) Figure 1 Nemertes Hemprichii Ehrenberg, 1831:12±13. Baseodiscus hemprichii: Gibson, 1979:146±153 (synonymy). material examined: Under lava boulder, intertidal zone, Anakena, Easter Island (Rapa Nui), Chile, 30 August 1999, coll. C. B. Boyko and S. Reanier: 1 specimen, 25 cm length (amnh 1512). distribution: This species has a broad Indo-Paci®c distribution and is known from the Red Sea to the Hawaiian Islands. This range is now extended southeastward to Easter Island. remarks: The Easter Island specimen had a white ground color with a single median stripe of purple along the dorsal margin 41 1 Funding for the Invertebrate Survey of Easter Island was provided by the U.S. National Park Service, Gateway National Recreation Area, Division of Natural Resources, as part of a Science Museum of Long Island/Explorers Club 5-yr research expedition to explore the impacts of El NinA o events on World Heritage Sites. Manuscript accepted 25 April 2000. 2 Division of Invertebrate Zoology, American Museum of Natural History, Central Park West at 79th Street, New York, New York 10024, and Department of Biological Sciences, University of Rhode Island, Kingston, Rhode Island 02881 (E-mail: cboyko@amnh.org). Paci®c Science (2001), vol. 55, no. 1:41±42 : 2001 by University of Hawai`i Press

The Stomatopod Alachosquilla floridensis (Manning, 1962) (Crustacea, Stomatopoda, Nannosquillidae) Reported from Guana Island, British Virgin Islands, with Observations on Color

Although color pattern can vary among and within species of the Crustacea, it can also be a conservative feature that can be very helpful in field identifications. This is often the case in the Crustacea Decapoda, where sibling species can be detected by subtle differences in color (e.g., Williams and Felder 1989, Zimmerman and Felder 1991, Knowlton and Mills 1992). Stomatopods are among the most colorful crustaceans when living. Many species show a great deal of variability (Manning 1969, Camp 1973), and knowledge of this coloration is often key to their identification in the field and in the lab (Schotte and Manning 1993). As part of an ongoing survey of the marine invertebrate fauna of Guana Island, British Virgin Islands, we collected 2 large (45 mm and 48 mm TL) females, and one male specimen (30 mm TL) of the rarely reported stomatopod species Alachosquillafloridemis (Manning 1962). To our knowledge, the species has been reported previously in the literature only 4 times (see Schotte and Manning 1993). These reports are based on a total of 8 specimens. Previous distribution records for the species include Lake Worth Inlet, Florida; Virgin Gorda, US Virgin Islands; Isla Marguerita, Venezuela; Bahia, Brazil; and Saint Giles Island and London Bridge Rock, Tobago, West Indies (Manning 1969, Schotte and Manning 1993). Alachosquilla floridensis was first described as Lysiosquillafloridensis by Manning (1962). The species was transferred to the genus Acanthosquilla by Manning (1963), along with L. digueti (Coutifere 1905) from the eastern Pacific. Later, Manning (1974) synonymized A. floridensis with A. digueti. Subsequently Schotte and Manning (1993) recognized the differences between the 2 species, and also placed the 2 into a newly created genus, Alachosquilla.

Devonian Vertebrates From Colombia

Vertebrate remains are reported from the Emsian–Eifelian Floresta Formation and the Late Devonian (?Frasnian) Cuche Formation of north‐eastern Colombia. The material from the Floresta Formation is associated with a marine invertebrate fauna and includes an arthrodire and probably a rhenanid. Several vertebrate‐bearing localities are recorded from the Cuche Formation; vertebrates occur with plant remains and lingulid fragments. They include an acanthodian (Cheiracanthoides? sp.), a chondrichthyan (Antarctilamna? sp.), placoderms (Bothriolepis sp., Asterolepis? sp. and an undetermined groenlandaspidid or primitive brachythoracid arthrodire), a stegotrachelid actinopterygianand three sarcopterygians (a cosmine‐covered form tentatively referred to an osteolepidid, the porolepiform Holoptychiussp., and the rhizodontid Strepsodus? sp.). This assemblage suggests a Late Frasnian age and is surprisingly similar to Late Devonian vertebrate assemblages found in similar facies of Europe and North America, notwithstanding the presence of the Gondwanan chondrichthyan Antarctilamna?. key words: Vertebrata, Devonian, Colombia, South America, biostratigraphy, palaeobiogeography.

Palaeomagnetism and magnetostratigraphy of uppermost Permian strata, southeast New Mexico, USA: correlation of the Permian-Triassic boundary in non-marine environments

Continental red sandstone and siltstone rocks of the Dewey Lake (Quartermaster) Formation at Maroon Cliffs, near Carlsbad, New Mexico, are characterized by two components of magnetization with partially overlapping laboratory unblocking temperature spectra. Both magnetizations display high coercivities (>100 mT), probably residing in haematite. A north-directed magnetization with steep positive inclination unblocks between 100 and 650 °C, isolating a predominantly northwest-directed magnetization, with shallow inclination, of near uniform normal polarity and maximum unblocking temperatures of 680 °C. We collected samples from 24 palaeomagnetic sites (i.e. individual beds) from a ~60 m thick section of flat-lying strata disconformably overlying carbonate and evaporite rocks of the Rustler Formation. The upper member of the Rustler Formation contains a Late Permian (early Changxingian) marine invertebrate and conodont fauna. Of the sampled sites, four yield only steep magnetizations, interpreted to be recent overprints. Eight sites did not yield well-grouped site means and were excluded from the final calculations. The formation mean (dec=337.7°, inc=9.2°; k=31.6, α95=7.8°, N=12 sites) defines a palaeomagnetic pole located at 55.2°N, 117.5°E, in good agreement with other Late Permian North American cratonic poles. Correlation of the short polarity sequence of this section of Dewey Lake strata is unambiguous. Compared with the polarity stratigraphy of marine sections in Asia, and supported by isotopic age determinations on a widespread bentonite bed in Dewey Lake strata in west Texas (approximately 251 Ma) and fossil data for the underlying Rustler Formation, the magnetostratigraphy is consistent with deposition of the Dewey Lake Formation during the latest Changxingian (Late Permian) stage.

Annotated Checklist of the Echinoderms From the Kiunga Marine National Reserve, Kenya. Part I: Echinoidea and Holothuroidea

The echinoderm fauna of the Kiunga Marine National Reserve, Kenya, is documented, based on the results of a field trip, and additional information from the literature. In this first paper, the Holothuroidea and Echinoidea are discussed. A total of 91 specimens representing eight orders, 13 families, 19 genera and 37 species were collected. Five other species were not collected but were identified in the field. Six additional species are reported from literature only and are not discussed. Diagnostic characters of every species recorded are given, as well as an assessment of their abundance in the Kiunga Marine Reserve. Clypeaster rarispinus, Phyllacanthus imperialis, Microcyphus rousseaui (Echinoidea), Holothuria (Cystipus) rigida, Holothuria (Platyperona) difficilis, Labidodemas pertinax, Stichopus chloronotus and Stichopus cf. monotuberculatus (Holothuroidea) are new records for Kenya. Holothuria (Theelothuria) turriscelsa is a new record for the Indian Ocean. This study stresses the importance of the Kiunga Marine National Reserve as a sanctuary in the conservation of the marine invertebrate fauna.

Biodiversity, speciation, and extinction trends of Proterozoic and Cambrian phytoplankton

The degradation-resistant organic-walled cell envelopes of acritarchs are the most abundant microfossils in Proterozoic and Cambrian rocks. These microfossils reveal diversity fluctuations that illuminate the nature of the record of primary producers near the Proterozoic/Phanerozoic boundary. Neoproterozoic radiations, some 1000–542 m.y. ago, reached levels comparable to those observed in the Cambrian Period. The microbiotas from rock successions from 13 Cambrian biochrons display significant fluctuations in the total number of microfossil taxa belonging to discrete microfossil assemblages. The assemblages reveal that Cambrian protist assemblages evolved over relatively short time spans, apparently out of low-diversity remnant populations after gradual declines in diversity. The characteristic microbiotas of the terminal Neoproterozoic and the Early, Middle, and Late Cambrian blossomed over relatively narrow time ranges, subsequently collapsing to nearly the initial levels. By virtue of the decreasing time spans involved in the late Vendian, Early, Middle, and Late Cambrian respectively, the tempo of specific turnover appears to have varied considerably. Speciation levels gradually decreased during Early and Middle Cambrian times and during Early Cambrian times were accompanied by rising levels of extinction. This latter feature seems to have reversed during Middle Cambrian times, lasting well into Late Cambrian times. Acritarchs were at the base of the marine trophic chain together with bacteria and other protists that are largely unrepresented in the fossil record. For this reason, the rise of diverse Cambrian protistan plankton must have been essential for early marine metazoan differentiation. Indeed, patterns of total diversity, speciation, and extinction of Cambrian acritarchs clearly mirror those of contemporaneous marine invertebrate faunas at the generic level.

A Late Cretaceous nodosaurid ankylosaur (Dinosauria: Ornithischia) from marine sediments of coastal California

A partial nodosaurid ankylosaur skeleton, consisting primarily of the ilia, hindlimbs, posterior dorsal armor, plus partial forelimb elements and additional armor, was recovered from the marine Point Loma Formation, late Campanian age, north of San Diego, California. The specimen is similar to contemporaneous species ofPanoplosaurusandEdmontoniafrom terrestrial sediments of the western interior, but there are also similarities to the armor ofStegopelta landerensisfrom marine sediments of earliest Cenomanian age from Wyoming. Skeletal elements critical for generic determination are not preserved, and the specimen is identified as Nodosauridae, incertae sedis. An associated marine invertebrate fauna and nannoplankton flora have revealed some discrepencies in the correlation systems used for Upper Cretaceous marine rocks of coastal California. Hollow limb bones of the specimen are interpreted as a preservational artifact. Nodosaurids had broad ecological tolerances, and visited riparian and coastal environments more frequently than other dinosaurs. However, a review of morphologic and distributional evidence fails to support a theory of amphibious or aquatic habits for nodosaurids.

Griesbachian (Earliest Triassic) palaeoenvironmental changes in the Salt Range, Pakistan and southeast China and their bearing on the Permo-Triassic mass extinction

Facies and faunal analysis from Pakistan and China show that the Permo-Triassic mass extinction of marine invertebrate faunas was associated with a spectacularly rapid Griesbachian transgression which lead to the widespread establishment of deep-water anoxic and dysoxic conditions. The extinction event was thus caused by habitat loss due to the extensive development of inhospitable conditions. The initial Griesbachian transgression in Pakistan produced extensive shallow, normal marine conditions in which Permian holdover taxa were able to survive until the development of dysaerobic facies in the late Griesbachian. The exceptionally complete sections of China show a three-phased deepening and extinction event beginning in the latest Permia. By the late Griesbachian a variety of dysaerobic and anaerobic facies were developed in all the regions studied. Several of these contain evidence for minimal sulphate reducing activity suggesting that marine productivity and thus organic matter flux to the sediments was very low in early Triassic seas.

Interpretation of Anisian (Middle Triassic) marine invertebrate faunas from the southwest Pacific

Early to Middle Triassic marine successions are remarkably lacking in the Southern Hemisphere. It would seem that the best developed and most fossiliferous sequences are preserved in New Zealand. To a lesser extent, successions of Early to Middle Triassic age are known from New Caledonia, New Guinea, the Gympie Basin of Eastern Australia, offshore Western Australia, and western South America (in particular Chile).Anisian marine faunas were first collected in New Zealand (Etalian local stage) in the 1940s but it was not until 1953 that their age significance was correctly recognised by Marwick. This was later confirmed by Kummel. Since then an unpublished doctoral study has been completed on the paleontology and biostratigraphy of the Anisian succession within the Murihiku terrane of Southland, South Island, New Zealand. A conclusion of this study, based on ammonoid correlations, was that the cosmopolitan halobiid bivalve Daonella appears earlier in New Zealand than it does in North America.Recent investigations post-date the advent of the tectonostratigraphic terrane concept and suggest that an Anisian fossil record is preserved in at least three terranes in New Zealand (Murihiku, Dun Mountain - Maitai and Torlesse terranes), and two terranes in New Caledonia (probably correlatives of the Murihiku and Torlesse terranes of New Zealand). Analysis of the faunal content of these various terranes suggests that although there are some facies differences (litho and bio), there is little obvious basis for recognition of distinct paleobiogeographic provenance.A corollary to this research on Anisian faunas is the recognition that the New Zealand ammonoid faunas previously considered to be Early Triassic (Malakovian local stage; Murihiku terrane) by Kummel are almost certainly Anisian. However, this does not imply that there isn't an Early Triassic sedimentary record. Significant thicknesses of apparently unfossiliferous sequence are present in each of the relevant terranes. Two isolated Early Triassic ammonoid faunas are now known from elsewhere in New Zealand but from tectonically complex settings in Brook Street (?) and Dun Mountain - Maitai terranes.

Paleobiology of the oldest known articulate crinoid

The evolutionary and ecological recovery of benthic marine invertebrate faunas from the devastating Permian-Triassic mass extinction is poorly understood. In particular. Paleozoic crinoids were decimated, creating an evolutionary bottleneck, so that Early Triassic (Scythian) and Anisian representatives of the genus Holocrinus may be considered the stem group for the monophyletic crinoid subclass Articulata, which includes all post-Paleozoic crinoids. Crinoid ossicles in limestones of the Scythian (Spathian) Virgin Limestone Member (Moenkopi Formation) of southern Nevada and southwestern Utah, identified as Holocrinus? smithi, respresent the oldest known Holocrinus. Limestone units of the virgin were deposited in nearshore and inner shelf environments of an arid epeiric seaway. Although these crinoids are generally completely disarticulated and occur commonly in storm-generated deposits. they are interpreted to have been deposited near their living sites in ‘disturbed neighborhood’ assemblages. Counts of ossicles in bulk samples indicate a relatively low number of individuals, suggesting that populations of H.? smithi occurred in scattered clumps or as isolated individuals. attached to hardgrounds or shell beds. Bivalves are the most common associates, and are commonly more numerous than the estimated number of crinoid individuals, although bivalve species richness is never greater than three. Virgin Limestone fossil assemblages probably represent the first redevelopment of relatively complex tiered epifiaunal communities in the Mesozoic. *Echinodermata, mass extinction, Early Triassic, paleoecology, Crinoida, Articulata.

Paleobiogeography of Mesozoic articulate brachiopods from the Western Cordillera of North America and their potential for paleogeographic studies

Mesozoic brachiopods were, at times, significant elements of marine invertebrate faunas. Current investigations suggest that Mesozoic brachiopods are more common in Mesozoic marine sequences from North America than has generally been assumed. Their neglect is no doubt in part due to the greater utility of other invertebrate and microfossil groups for biostratigraphy. Brachiopods may be preserved in original shell material or silicified. It is therefore necessary to consider which is the most appropriate method of extraction, depending on type of preservation.Lacking planktotrophic larval stages, living articulate brachiopods are limited in their dispersal potential by virtue of their sessile, benthic mode of life. If, in addition, all post-Paleozoic articulate brachiopods possessed a non-planktotrophic larval stage endemism would be likely to develop if gene-flow became severed. This would mean that taxonomic investigation of articulate brachiopods has the potential to provide useful paleobiogeographic and paleogeographic information. Recent investigations have concentrated on making a preliminary survey of some brachiopod occurrences in the Western Cordillera of North America with these goals in mind.The Upper Triassic brachiopod fauna from the Luning Formation of the Pilot and Shoshone Mountains, Nevada, is the most diverse known for the Mesozoic of North America in terms of number of brachiopod species (manuscript submitted with George D. Stanley). This is probably a reflection of how little detailed collecting and systematic study Mesozoic representatives of the phylum have received in North America. The fauna comprises both Tethyan and endemic species. The brachiopods are from the Paradise terrane, probably close to the North American craton in the Late Triassic. One Upper Triassic brachiopod fauna from the Antimonio Formation, Sonora, is by comparison with the Nevada faunas, depauperate, but they do share one common species. Additional time-equivalent brachiopod faunas from outboard terranes of North America and the “classic” European faunas monographed in the nineteenth and early twentieth centuries require investigation to determine their paleobiogeography and their contribution to paleogeography.Jurassic brachiopods from North America have not been subjected to any major revision but they are present at certain horizons. Cretaceous faunas from the southern United States and Mexico contain genera known from Tethys in Europe. Mid-Cretaceous faunas from the Queen Charlotte Islands (Wrangellia terrane) and the Canadian Arctic Islands contain forms that are more typical of mid-latitude to Boreal regions, repectively, of Europe. This suggests a broad correspondence between brachiopod distributions and paleolatitude across considerable paleolongitudinal distances, an observation of relevance to interpreting Early Mesozoic paleobiogeographic distributions.The current work is only scratching the surface of the Phylum's distribution in the Western Cordillera of North America. The aim is to provide a better understanding of brachiopod paleobiogeography, paleogeography, and the evolutionary history of the Brachiopoda during the post-Paleozoic, which does not appear to be their swansong.

Vascular land plant diversity in a biogeographic context

The history of vascular land plant diversity from the late Silurian to the Early Carboniferous has two major features: a pronounced diversity peak in the late Siegenian-Emsian (Devonian), approximately 12 million years after the appearance of vascular land plant body fossils; and a diversity low in the late Frasnian-early Famennian (Devonian), which coincides with the Frasnian-Famennian mass extinction of marine invertebrate faunas. Because the diversity of fossil land plants depends in part on sampling intensity, this diversity history requires evaluation. Biogeographic data are useful for assessing diversity histories because they incorporate one of the best measures of sampling intensity, the number of localities known from a time interval, and because the amount of biogeographic differentiation present during an interval may influence global diversity.The data for this study consist of compression-impression genera from 394 Late Silurian-Devonian and 64 Tournaisian (Early Carboniferous) floral assemblage lists. Most of these assemblage lists represent florules: defined as the compression-impression genera found in a single formation, member, or other narrow stratigraphic horizon at a single outcrop. However the data include some regional lists from China and parts of the former U.S.S.R., because we could not obtain florules for all time intervals from these regions. Regional lists consist of the genera found in one formation from a limited geographic region. All of the Laurussian assemblage lists used in this study (244 Late Silurian -Devonian and 49 Tournaisian lists), including those from the Russian platform, represent florules. Linear regression of both the total diversity and the standing diversity of vascular land plant genera against the number of floral assemblage lists from each interval suggests that the number of floral assemblage lists correlates strongly and significantly with generic diversity (r = 0.88). Thus, the late Siegenian-Emsian diversity peak is probably an artifact of sampling: there are more florules described from the late Siegenian-Emsian than from the Eifelian and Givetian combined. The late Frasnian - early Famennian diversity low may be an artifact of sampling: few reliably-dated assemblages exist for this interval. However, late Frasnian - early Famennian assemblages show no biogeographic differentiation between ‘equatorial’ Laurussian assemblages from the United States and Europe and northern ‘non-equatorial’ assemblages from Arctic Canada and Siberia. This biogeographic differentiation is a persistent feature of floral assemblages from all other Devonian time intervals, and from the Early Carboniferous. Low numbers of florules could cause an apparent loss of biogeographic differentiation for an interval. Conversely, all three phenomena (low diversity, low numbers of florules, and loss of biogeographic differentiation) may indicate that the Frasnian-Famennian mass extinction affected terrestrial land plants.The diversity history of Late Silurian through Early Carboniferous land plants suggests that three major evolutionary innovations: heterospory, which appeared in the late Emsian; arborescence, which appeared in the Givetian; and seeds, which appeared in the late Famennian had little effect on land plant diversity.

Paleobiogeography of Devonian vertebrates

Five distinctive vertebrate faunas characterised by endemic taxa can be recognised for the Early Devonian (Euramerica, Siberia, Tuva, China, and East Gondwana). By Late Devonian time these faunal provinces are obscured by widespread taxa which also inhabited nonmarine aquatic environments, but indicate faunal communication between Gondwana, Euramerica and China. This marked change in pattern between the Early and Late Devonian may be attributed to intrinsic (evolutionary) or extrinsic causal factors. Dispersal capabilities of aquatic vertebrates may have increased during the initial gnathostome radiation of the Devonian, but a predominantly extrinsic cause (e.g. global change in geography or climate) is suggested by the similar pattern for marine invertebrate faunas of Early Devonian endemism and Late Devonian cosmopolitanism. Outstanding problems of Devonian vertebrate biogeography include faunal differentiation on the largest landmass of the time (Gondwana), and the nature of barriers and connections between East and West Gondwana, East Gondwana and South and North China, and West Gondwana and Euramerica. A vertebrate equivalent of the cool-water Malvinokaffric invertebrate faunal realm of the Siluro-Devonian is not clearly identified, but vertebrate data from southern Africa and south America are sparse.Wide latitudinal distributions for some Late Devonian vertebrate taxa appear anomalous, and could indicate either reduced global climatic gradients, or erroneous paleogeographic base maps. There are difficulties in formulating a hypothesis of global warming and/or major paleogeographic change in a way which clearly distinguishes basic from interpreted data. Three major subdisciplines (paleomagnetism, paleoclimatology, paleobiogeography) contribute to Paleozoic paleogeographic reconstructions. Their data tend to be organised and represented in different ways, but each relies on the same principle of concordance with a general pattern (Young 1990). Degree of consilience of a hypothesis based on one data set (the extent to which it explains patterns within an unrelated set of data) is a primary criterion for accepting or rejecting the hypothesis. Apparent polar wander path representation facilitates testing of paleomagnetic data against those paleoclimatic or paleobiogeographic data which provide evidence of paleolatitude. However, as well as the simple indication of paleolatitude, biogeographic and some other qualitative data sets provide more complex evidence concerning connections or barriers between regions, for which APWP representation is not appropriate. Cladistic analysis of hierarchically organised data sets (Young, 1986, 1987) provides a means of integrating qualitative paleobiogeographic, paleoclimatic, and paleogeographic data such that inconsistencies in the evidence are emphasised, and the hypothesis is exposed to falsification. These ideas are illustrated using Devonian examples.

Magnetic Polarity Stratigraphy of the Pliocene Hamilton and Forsyth's Bank Local Sections, Hamilton (Victoria), Australia

The Hamilton Local Fauna has the combined assets of being a large and well studied mammalian fauna and being directly overlain by a dated basalt. The overlying basalt () gives it the best constrained age of any fauna on the Australian continent and makes it an important Pliocene locality. This study provides a basal absolute age for the Hamilton Local Fauna through the use of magnetic polarity stratigraphy. The fauna occurs within a zone of normal magnetic polarity correlated to the Gilbert Chron at 4.40-4.47 Ma. Therefore, the age of the Hamilton Local Fauna is constrained to fall within a range of and 4.47 Ma. A section that contains the nearby Forsyth's Bank mammal fauna was also studied. A characteristic magnetic component could not be isolated in samples taken from this section. The age of this locality remains constrained by the Kalimnan Stage marine invertebrate fauna that it contains and by the overlying basalt dated at .

Environment of deposition of the Maungataniwha Sandstone (Late Cretaceous), Te Hoe River area, western Hawke's Bay, New Zealand

Abstract The Maungataniwha Sandstone is a remarkably thick (c. 400 m), poorly bedded, transgressive, sandstone-dominated unit of Campanian-Maastrichtian age (late Piripauan to early Haumurian). It was deposited during continued slow subsidence, and possibly records onlap over a dissected coastal plain and/or stacking of several minor transgressive and regressive cycles. It contains a diverse, dominantly marine vertebrate and invertebrate fauna, but includes terrestrial vertebrates, invertebrates, and plants. Marine fossils were probably not significantly transported or mixed prior to burial, and indicate deposition in a fully marine, nearshore, shallow water, moderate to high energy environment, possibly within an estuary, bay, or inlet. Three benthic invertebrate assemblages are recognised, and these may correspond to different habitats within such an environment. A nearby river mouth or delta is implied by the abundance of terrestrially derived material. Information on environment of deposition from sedimentary structures, grain-size analyses, and trace fossils is consistent with faunal evidence. In addition, it indicates that the lowest part of the Maungataniwha Sandstone was deposited mainly on the foreshore or shoreface, above fair-weather wave-base, and that the bulk of this unit was deposited under gradually deepening conditions on the inner shelf, above storm wave-base. Rare phosphatic concretions, of diagenetic origin, are considered to be derived from decaying organic matter.

Climatic and biotic change in the late Triassic

Generally arid conditions that pervaded much of Europe and North America during the late Triassic were interrupted by a wet monsoonal climatic phase during Middle and Late Carnian times. Extensive fluviatile sandstones deposited at this time throughout the region, occur within a thick sequence of playa-lake mudstones. The sandstones occasionally contain kaolinite, suggesting a humid climate. An extreme δ 13 C depletion in a shallow marine sequence of this age in Israel has been interpreted as evidence for an influx of freshwater. A widespread change from carbonates to clastics in marine sequences at this time may also be climate-related. Water-course cave systems in limestone areas exposed during the late Triassic indicate high levels of runoff during the Middle and Late Carnian. The marine invertebrate fauna shows a significant turnover at the end of the Early Carnian. The terrestrial fauna and flora were relatively unaffected at this time but subsequently diversified prior to a major biotic turnover at the Carnian-Norian boundary. These periods of biotic change appear to be synchronous with the onset and cessation of a Carnian humid phase. The change to a monsoonal climate during this interval has been documented over more than 90° of longitude between 5° and 50° north of the Triassic equator. It may have been caused by rising atmospheric CO 2 levels due to volcanism associated with the incipient dispersal of Pangaea.

COMPLETE LARVAL DEVELOPMENT OF GALATHEA INTERMEDIA LILLJEBORG REARED IN LABORATORY CULTURE (ANOMURA: GALATHEIDAE)

Larvae of East Atlantic anomuran crab Galathea intermedia Lilljeborg were reared in laboratory from hatching to juvenile stage. The larvae were kept in 3 l-32%o S sea water at 15°C. The complete larval development consists of 4 or 5 zoeal and 1 megalops stage. The larval are described and morphological characters are compared with those of West Atlantic species Galathea rostrata A. Milne Edwards described by Gore (1979). Galathea intermedia Lilljeborg, 1851, oc­ curs along eastern coasts of Atlantic from northern Norway (Christiansen, 1972) to Dakar (Zariquiey Alvarez, 1968). The species has also been reported from Angola, and it occurs in entire Mediterranean (Holthuis, 1961). It is most common in depths between 8 and 100 m (Holthuis, 1950). It is a very common species in all deeper parts of German Bight (North Sea), living in particularly high numbers be­ tween mollusc shells near island of Hel­ goland (Caspers, 1950). Its meroplanktonic were most abundant anomuran larvae in this area, occurring from June through October (Fiedler, 1987). The larvae of G. intermedia were dealt with by Sars in 1889. He described lar­ vae of three species of Galathea, G. in­ termedia, G. nexa Embleton, and G. squamifera Leach together, figuring certain stages, and only last larval and first postlarval of G. intermedia. Webb (1921) gave a short description of larval stages of genus Galathea based on four species G. dispersa Bate, G. intermedia, G. squamifera, and G. strigosa (Linnaeus) recorded in Plymouth Marine Invertebrate Fauna, with figures of first larval of G. squamifera, and telson and uropods of fourth larval of Galathea sp. Based on larvae hatched from eggs and larvae from plank­ ton, Lebour (1930, 1931) described larval of G. dispersa, G. strigosa, G. squam­ ifera, and G. intermedia and made a key of zoeal larvae of four species. Unfor­ tunately, descriptions and figures by Le­ bour are of limited value for identifying lar­ vae from plankton. Bull (1937) described and second zoeal of G. nexa and expanded Lebour's key to include larvae of all five British species of Galathea. Gurney (1939, 1942) referred to Sars' and Lebour's descriptions of larvae of G. inter­ media. Pike and Williamson (1972) made keys to zoeal and megalops of Galatheidae in which G. intermedia is included. The complete description of all larval of a species of Galathea was pub­ lished by Gore (1979), who cultured larvae of western North Atlantic species G. ros­ trata A. Milne Edwards in laboratory. As he pointed out, the lack of detailed de­ scriptions in earlier studies on galatheid lar­ val morphology prevents comparative statements to be made among most of species for which larvae are known. The present paper gives a complete descrip­ tion of all larval of a second species, G. intermedia. The larvae were reared from hatching to crab stage under labo­ ratory conditions, and their morphology is compared with that of G. rostrata.

The marine invertebrate fauna of a British coastal salt marsh

There are few accounts in the literature of the marine fauna of European salt marshes. The marine invertebrate populations of a coastal salt marsh in eastern England were studied for two years. A total of 32 marine species were recorded. The community was composed of a subset of species from adjacent intertidal sand and mud flats, along with a brackish water component. This gave the marsh a characteristic fauna, which was dominated by infaunal and surface‐living deposit feeders. The community showed a seasonal minimum in winter, and the infauna showed an additional summer decrease. This is attributed to increased interstitial salinities. Principal component analysis revealed the importance of the tidal gradient and the structure of the habitat in determining the community. The abundance of both epibenthic and infaunal predators were negatively correlated with the abundance of some prey. Also a small number of other pairwise negative interactions were revealed, but overall there was no strong evidence of interspecific competition exerting much influence on the community. The role of habitat heterogeneity and variation in the lateral movement of adult benthos and larval recruitment as promoters of diversity are discussed.

Four new species of southern African octocorals (Cnidaria: Alcyonacea), with a further diagnostic revision of the genus Alcyonium Linnaeus, 1758

Four new species of soft corals are described from the shallow sublittoral of southern Africa. Three of the species are referable to the genus Alcyonium Linnaeus, 1758 (family Alcyoniidae), although two of these possess growth forms that are atypical for most members of the genus. A revised diagnosis of the genus is therefore included. A new species in the family Nephtheidae is also described, this being referable to the genus Capnella Gray, 1869. All four species are from the region between the Cape of Good Hope Peninsula and the eastern Cape Province of South Africa. This is the region of the Agulhas Bank, an austroafrican biogeographic region that shows a high incidence of endemism with respect to the marine invertebrate fauna.