Abundant and well-preserved assemblages of disarticulated sponge spicules occur in Middle and Late Cambrian platform carbonates of western Hunan, China. Assemblages recovered from 11 stratigraphic horizons include calcisponges, demosponges, and hexactinellids. Hexactinellida, in particular, are both abundant and diverse in Upper Cambrian carbonates. Comparison with spicule assemblages from Australia indicates that many of these taxa have long stratigraphic ranges, limiting their use in correlation. The morphological diversity of these spicules exceeds that known for living siliceous sponges, supporting the observation that during the Cambrian radiation, sponges, like other metazoans, evolved a variety of architectural forms not observed in later periods. Like conodonts, individual sponges can produce more than one spicule form; thus, an “apparatus genus” concept based on multiple cooccurring elements may eventually prove useful in the biostratigraphic and paleobiological interpretation of disarticulated sponge spicules. Four distinctive forms are recognized as new taxa: Australispongia sinensis new genus and species, Flosculus gracilis new genus and species, Pinnatispongia bengtsoni new genus and species, and Nabaviella paibiensis new species.

New fossils from the Neoproterozoic Ediacara fauna of South Australia are interpreted as the oldest known hexactinellid sponges. They occur within the Ediacara Member of the Rawnsley Quartzite (Pound Subgroup) from several locations in the Flinders Ranges. The new genus, Palaeophragmodictya, is characterized by disc-shaped impressions preserving characteristic spicular networks and is reconstructed as a convex sponge with a peripheral frill and an oscular disc at the apex.

Twenty-two taxa of stromatoporoids are described from the outcrop belt of the Elm Point, Winnipegosis, Dawson Bay, and Souris River Formations in Manitoba. The Elm Point Formation contains a fauna of stromatoporellids of Eifelian age that is characterized by the new species, Stromatoporella manitobaensis. The Winnipegosis stromatoporoids are dolomitized but the widespread species Actinostroma tyrrelli, Taleastroma logansportense and the new species Trupetostroma imbrex can be recognized in this Givetian assemblage. The Dawson Bay fauna is characterized by the appearance of the dendroid forms, Stachyodes and Dendrostroma and species of Hermatostroma, Trupetostroma, and Parallelopora. A species of Actinostroma, comparable to A. filitextum is the most abundant stromatoporoid in the Dawson Bay Formation. The Souris River fauna, referred to as the Arctostroma contextum assemblage, is widespread at the Givetian-Frasnian boundary. Elements occur elsewhere in western Canada in the Beaverhill Lake, Waterways, lower Duperow and lower Fairholme units. Stromatoporoids in these four assemblages are relatively restricted in their stratigraphic occurrence and sufficiently widespread in their distribution to be useful in correlation.

A distinctive spiral unilaminate cyclostome bryozoan, recently discovered in the Eocene Castle Hayne Limestone Formation of eastern North Carolina, is described as Crisidmonea archimediformis new species. Colonies have a thickened spiral axis bearing systems of bifurcating branches. When worn and stripped of their branches, the resistant axes closely resemble the familiar screws of the Carboniferous to Permian fenestrate bryozoan genus Archimedes. However, the Eocene screws are shorter and become more loosely coiled with growth, corresponding to a helicospiral rather than a helical form. The paleoenvironment inhabited by C. archimediformis colonies is inferred to have been on the shallow (< 30 m depth) margin of an open marine, waveswept embayment. Autozooid distribution and the gradient of increasing apertural size from branch reverse to frontal sides in C. archimediformis resemble those of the living cyclostome Exidmonea atlantica and suggest colonial water currents that flowed upwards and inwards through the spiral colony. Polyascosoecia, a genus closely related to Crisidmonea, is shown to be an objective junior synonym of Reteporidea, and the new genus Polyascoeciella (type species Idmonea foraminosa Reuss) is introduced for species with exterior-walled gonozooids that were previously assigned to Polyascosoecia.

The record of the fossil representatives of the family Juliidae is updated. The new genus Candinia is proposed, in the subfamily Juliinae, for two fossil species somewhat intermediate between Julia and Berthelinia. The new species Candinia pliocaenica is recorded from the lower Pliocene shallow marine deposits near Siena (Tuscany, Italy). This is the first record of Sacoglossa in the Mediterranean Basin. Based on the very specialized life habits of the Juliidae, it is suggested that subtropical Caulerpa algal prairies inhabited the Mediterranean during the early Pliocene, likely becoming extinct in this basin because of the mid-Pliocene climatic deterioration.

The fossil record of the volutid gastropod Arctomelon is represented by three species from the Koryak Upland and the Kamchatka Peninsula (Russian northeast), ranging in age from late middle Eocene to early Miocene. Although Recent Arctomelon stearnsii (Dall, 1872) from the northeastern Pacific is a cold-water species, paleontological data point to the origin of the genus in shallow, warm-water conditions that existed in high latitudes of the northwestern Pacific during Paleogene time. The fossil record also indicates survival of the genus during the climatic coolings through the Cenozoic. It is apparent that Arctomelon successfully adapted to the new cooler and deeper-water conditions. Despite this major change of life habit, shell morphology has remained fairly unchanged since the Eocene. Two new species of the genus Arctomelon, A. harasewychi sp. nov. and A. rateginense sp. nov., are described.

The Anacacho Limestone was deposited during the Campanian and represents two depositional intervals, one of early Campanian and one of middle Campanian age. These two intervals correspond to periods of major eustatic sea level rise. This study focuses on the molluscan paleontology of the middle Campanian interval in the eastern part of the Anacacho exposure belt in Medina County, Texas. Molluscan assemblages in this area are indicative of inner to mid-shelf environments. No significant reef components are present. These eastern Anacacho deposits are interpreted to represent more offshore, deeper water environments than those to the southwest, where reef and lagoonal deposits have been reported.

Analysis of the macrofossil components from these eastern localities has expanded the number of invertebrate species known from the Anacacho Limestone by nearly three-fold. This increase in diversity, based on a small amount of new work, suggests that many more taxa are yet to be identified, particularly in the western part of the exposure belt in Uvalde and Kinney Counties. This paper documents the bivalve and gastropod fauna, discussing and illustrating 24 bivalve taxa and 11 gastropod species. Two new bivalve species are named, Panopea anacachoensis new species and Spondylus siccus new species, and two potentially new gastropod species are identified but not named herein due to inadequate material. This paper expands the distribution of many eastern Gulf Coast and Atlantic Coast taxa westward into Texas and shows strong ties between the Anacacho fauna and that of the Campanian Tar Heel and Bladen Formations of the Black Creek Group in North Carolina. The taxonomic ties between these two areas probably reflect the thorough documentation of the North Carolina fauna, which is the best documented Campanian bivalve fauna in the Gulf or Atlantic Coast regions.

At the southernmost tip of South America, a thick pile of deep marine volcaniclastic rocks called the Yahgan Formation (Kranck, 1932) was deposited during the Early Cretaceous in a small marginal basin developed between the continent and a Pacific-facing volcanic arc (Katz, 1972; Dalziel et al., 1974). North and northwest of Tierra del Fuego, in the adjacent Austral or Magallanes basin, this unit is laterally replaced by coeval, fine-grained deposits representing basinal, slope, and platform marine settings (Winslow, 1982; Biddle et al., 1986; Wilson, 1991). The geometry of the basins changed markedly with a compressional event that produced the tectonic inversion of the marginal basin and the formation of a retroarc foreland basin in front of the rising cordillera. Closure of the marginal basin and strong deformation of the Yahgan Formation apparently occurred in the mid-Cretaceous (Halpern and Rex, 1972; Dalziel et al., 1974; Wilson, 1991); however, the timing of the opening and closing of the basin is poorly constrained because of the scarcity of fossil evidence. So far, a Late Jurassic-Neocomian age was favored for the Yahgan Formation on the basis of the record of belemnites and ammonites (Aguirre Urreta and Suárez, 1985; Halpern and Rex, 1972; Winn, 1978). Halpern and Rex (1972) mentioned the Hauterivian genus Favrella in Gardiner Island, but this record has been questioned by Thomson et al. (1982) who considered the ammonite imprint to be some kind of heteromorph. Also, the timing of the transition from marginal to foreland basin is not well documented. On the basis of indirect evidence the initiation of the foreland basin stage was assigned to the Albian in the Ultima Esperanza region of Chile (Wilson, 1991) and to the Late Cretaceous in northern Tierra del Fuego (Biddle et al., 1986). Recent field work by the authors in the area of No Top Mountain-Moat River, Tierra del Fuego (Figure 1), has resulted in the first record of diagnostic late Albian inoceramids in the Yahgan Formation. The objective of this note is to document this fauna and to briefly discuss its implications on the control of the timing of the transition from marginal to foreland basin in the area.

Phosphatized, three-dimensional cuticle fragments of the palaeoscolecids Houscolex lepidotus new genus and new species, Houscolex species indeterminate, and an unidentified form are described from the Lower Cambrian Qiongzhusi Formation of Shaanxi, China. These segmented worms, characterized by regularly arranged simple plates and platelets, small circular pores and fine pits, and irregularly distributed nipplelike protuberances, are unique among known palaeoscolecids. The occurrence of such cuticles as seemingly persistent elements of phosphatized faunas suggests that wormlike organisms achieved a fairly high diversity and widespread geographic distribution during the Early and Middle Cambrian.

The remarkable “evolution” of the reconstructions of Anomalocaris, the extraordinary predator from the 515 million year old Middle Cambrian Burgess Shale of British Columbia, reflects the dramatic changes in our interpretation of early animal life on Earth over the past 100 years. Beginning in 1892 with a claw identified as the abdomen and tail of a phyllocarid crustacean, parts of Anomalocaris have been described variously as a jellyfish, a sea-cucumber, a polychaete worm, a composite of a jellyfish and sponge, or have been attached to other arthropods as appendages. Charles D. Walcott collected complete specimens of Anomalocaris nathorsti between 1911 and 1917, and a Geological Survey of Canada party collected an almost complete specimen of Anomalocaris canadensis in 1966 or 1967, but neither species was adequately described until 1985. At that time they were interpreted by Whittington and Briggs to be representatives of “a hitherto unknown phylum.”

Here, using recently collected specimens, the two species are newly reconstructed and described in the genera Anomalocaris and Laggania, and interpreted to be members of an extinct arthropod class, Dinocarida, and order Radiodonta, new to science. The long history of inaccurate reconstruction and mistaken identification of Anomalocaris and Laggania exemplifies our great difficulty in visualizing and classifying, from fossil remains, the many Cambrian animals with no apparent living descendants.

A new genus and species of crab is described from the late Maastrichtian Meerssen Member of the Maastricht Formation at the type area of the Maastrichtian Stage, SE Netherlands. This new taxon could well be the ancestor of the xanthid Prochlorodius-Chlorodiella group and its occurrence provides additional evidence of a late Cretaceous radiation among the decapod crustaceans.

The description of Lophoranina precocious new species from the Late Cretaceous (early Maastrichtian) Ocozocuautla Formation, Chiapas, México, represents the first occurrence of Lophoranina in pre-Eocene strata. The discovery provides documentation that the evolutionary development of terraced lines in the genus trended from relatively few, undivided, symmetrical terraces to more numerous, divided, asymmetrical terraces, and that the overall carapace surface developed a lower relief and became more uniform through time. Terraced lines that appear to be nodose, in most cases, were probably spinose. The morphology of the dorsal carapace seems to support affinities of the Raninidae with the Homolidae.

Examination of 186 specimens of the living brachiopod Laqueus rubellus (Sowerby), collected during four different months from Sagami Bay, Japan, has yielded 94 specimens of the pinnotherid crab, Pinnotheres laquei Sakai, living within the mantle cavity. This work provides the first quantitative statements regarding crab/brachiopod associations. All but four of the specimens were female crabs; the four male specimens occurred together with females in brachiopods collected during March, 1982. Pinnotherids, common associates of mollusks and echinoderms, tend to be host specific; however, anecdotal information received near the conclusion of this study suggests that P. laquei may visit multiple brachiopod host species. Although the crabs seem to be more common in larger brachiopods, there is some correspondence between crab size and brachiopod size. No physical evidence, such as malformation of the shell or lophophore loop, was observed in host brachiopods and, therefore, the association was judged to be commensal or symbiotic. It is probable that crabs were able to enter and exit the mantle cavity at will. This association of brachiopod and pinnotherid represents the only known occurrence of infestation of brachiopods by crabs and, with the exception of boring and encrusting organisms, is one of very few biotic associations, of any kind, for brachiopods. Although this association has not yet been reported from the fossil record, the nature of preservation of brachiopods and the methods of study, employing serial sectioning techniques, suggest the possibility of detecting this unusual association in the fossil record.

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 of Panoplosaurus and Edmontonia from terrestrial sediments of the western interior, but there are also similarities to the armor of Stegopelta landerensis from 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.

Many ichnological taxa named by Edward Hitchcock have never been adequately described and illustrated. Among these is the ichnogenus Antipus Hitchcock (1858, p. 115) with two species: A. flexiloquus based on specimens AC (=Amherst College, Amherst, Massachusetts) 35/25 and AC 41/52 (designated the type specimen by Lull 1904, p. 536); and A. bifidus based on specimens AC 23/3, AC 17/2, and AC 23/2 (designated the type specimen by Hitchcock 1865, p. 56). Lull (1904, p. 536) regarded A. bifidus as “… extremely doubtful…” and did not consider it in later publications (e.g., Lull 1915, 1953). The impressions ascribed to A. bifidus might be organic in origin, but if they are trackways, they are totally unlike the tracks of A. flexiloquus. Antipus bifidus is here regarded a nomen dubium because it is undiagnostic. Referred specimen AC 35/25, a small, thin slab of micaceous shale (approximately 87 mm by 96 mm, less than 2 mm thick) that is not mentioned by Lull (1904, 1915, 1953), has one manus and possibly one pes track of such poor quality that analytic comparison to the type of A. flexiloquus is impossible. Therefore, the ichnogenus Antipus has a single species, A. flexiloquus, known only from the type specimen, AC 41/52. Two of the eleven tracks on AC 41/52 have been illustrated (Hitchcock 1858, plate 20, fig. 10; republished with minor revision by Lull 1915, fig. 117; these two tracks are here designated M2 and P4). These simple outline sketches do not accurately portray details of the tracks, and the full trackway pattern was not illustrated.

The micromorphic brachiopod genus Gwynia was established by William King (1859) on the basis of specimens described by Gwyn Jeffreys (1859) from the coast of Normandy and Belfast Lough. Additional, unpublished records of the genus from Larne and Portrush, collected by Dickie, Hyndman and Waller during the 1850s, were the last sightings of the taxon around Ireland (Massy, 1925). Despite the distinctive characteristics of the genus, Davidson (1861, p. 39) considered it had yet to be sufficiently determined whereas others (see Brunton and Curry, 1979, p. 46) have suggested the genus may be an immature form of Argyrotheca cistellula (Searles-Wood) with which Gwynia often co-occurs. However, that species is consistently transverse with marked exopunctae.

Unusual preservation of blastoid hydrospire meshwork in a single Mississippian specimen was described by Beaver (1981). Examination of additional specimens from different stratigraphic units has revealed other specimens of Mississippian age showing the same hydrospire meshwork.

One of the rarest pterosaurs from the Upper Jurassic Solnhofen Limestone of southern Germany is Pterodactylus suevicus. Only two specimens are known: the holotype, consisting of a virtually complete skeleton described by Quenstedt (1855); and a second specimen, consisting of only postcranial elements described by Wagner (1858) and lost during World War II (Wellnhofer, 1970). Seeley (1870) noted that P. suevicus differed from P. antiquus, the type species of Pterodactylus, in a number of significant points. Therefore, he placed P. suevicus in a new genus, Cycnorhamphus. Seeley (1870:111) gave the following diagnosis of Cycnorhamphus:

The character “nares very small” was the result of a misinterpretation of depressions on the premaxillae that probably resulted from crushing, and “middle hole of the skull” referred to the confluent naris and antorbital fenestra, which Seeley apparently considered the antorbital fenestra alone.

The monoplacophoran genus Protoconus Stinchcomb, 1986, from the Upper Cambrian of the Ozark Uplift of Missouri, is a junior homonym of the monoplacophoran Protoconus Yü, 1979. Protoconus is a significant element in the pre-trilobite Lowermost Cambrian (Meishucan) beds of China (Yü, 1987). In consideration of this homonymy, it is proposed that Protoconus Stinchcomb, 1986, is changed and designated as Proteroconus.