Sinodiversograptus Mu and Chen, 1962, from the Monograptus turriculatus Zone of the lower Telychian (=Upper Llandovery, Silurian), is the earliest known Silurian graptolite genus to bear thecal cladia. Only one species of sinodiversograptid is known, this being S. lientanensis (Mu, 1948). A mature specimen of this species is illustrated in Figure 1. The genus Sinodiversograptus has been portrayed as such in both the Treatise (Bulman, 1970) and in Rickards et al.'s (1977) analysis of the evolution of the Silurian and Devonian graptoloids. Mu and Chen (1962), however, in their detailed study of the astogeny of the conspecific S. multibrachiatus, noted that the development of Sinodiversograptus may be divided into three stages.

1) Streptograptid stage (Figure 2.1)—development is as in a normal monograptid, with the first theca arising from the sicula. Subsequent thecae are added sympodially. Rickards et al. (1977) noted that the thecae of Sinodiversograptus are not streptograptid in form (i.e., retroverted, with an aperture slit-like laterally, but possessing a median upturned lip—see Chen, 1986, for illustrations of chemically isolated streptograptid thecae), but are hooked (Figure 2.8), an observation also made by the present author of the thecae of Mu and Chen's (1962) specimens (housed in the Nanjing Institute of Geology and Palaeontology). They most closely resemble the thecae of Monograptus runcinatus Lapworth, 1876, as illustrated, for example, by Bjerreskov (1975). This first stage of development might, therefore, more correctly be termed the monograptid stage.

Species of the late Osagean and early Meramecian advanced cladid crinoid genera (suborder Poteriocrinina) Abrotocrinus, Aulocrinus, Cromyocrinus. Decadocrinus, Dinotocrinus, Holcocrinus, Hylodecrinus, Lanecrinus n. gen., Pachylocrinus, Parascytalocrinus n. gen., and Stinocrinus from Illinois, Indiana, Iowa, Kentucky, and Missouri are redescribed and redefined from study of type material and museum collections. Nomenclatural and systematic acts include the following: 1) Abrotocrinus cymosus Miller and Gurley, 1890a, is a valid species and not a synonym of A. coreyi (Meek and Worthen, 1869); 2) A. coreyi is a senior synonym of Poteriocrinus orestes Worthen, 1882; 3) Scaphiocrinus manus Miller and Gurley, 1890a, is assigned to Abrotocrinus; 4) Abrotocrinus granulatus n. sp. is described; 5) S. bellus Miller and Gurley, 1890a, is assigned to Aulocrinus and is a senior synonym of Aulocrinus agassizi Wachsmuth and Springer, 1897; 6) S. orbicularis Hall, 1861a, is assigned to Cromyocrinus; 7) P. latidactylus Worthen, 1882, is assigned to Dinotocrinus; 8) S. gibsoni White, 1878, is assigned to Hylodecrinus with P. nauvooensis Worthen, 1882, questionably placed in synonymy; 9) P. briareus Worthen, 1882, is assigned to Hylodecrinus and is a senior synonym of S. lacunosus Miller and Gurley, 1890a, S. boonvillensis Miller, 1891b, S. constrictus Miller, 1891a, and S. arrosus Miller and Gurley, 1893; 10) S. bonoensis Miller and Gurley, 1890a, is assigned to Hylodecrinus; 11) Hylodecrinus robustus n. sp. is described; 12) P. validus Worthen, 1882, is questionably assigned to Hylodecrinus; 13) Lanecrinus n. gen. is described and the following species are assigned to this new genus: S. halli Hall, 1861 a, S. depressus Meek and Worthen, 1870, P. milleri Wetherby, 1881, P. fountainensis Worthen, 1882, S. repertus Miller and Gurley, 1890a, and Ramulocrinus consectatus Strimple and Watkins, 1969; P. otterensis Worthen, 1882, is questionably assigned to Lanecrinus; 14) Lanecrinus depressus is the senior synonym of P. ulrichi Worthen in Miller, 1889, and S. maniformis Miller, 1892; 15) Lanecrinus repertus is the senior synonym of S. gorbyi Miller, 1891a; 16) P. asper Worthen, 1882, is assigned to Pachylocrinus and is a senior synonym of S. extensus Wachsmuth and Springer, 1886; 17) Parascytalocrinus n. gen. is described and the following species are assigned to this new genus: Poteriocrinus hamiltonensis Worthen, 1882, and Scytalocrinus validus Wachsmuth and Springer, 1897; 18) Poteriocrinites mcadamsi Meek and Worthen, 1873, is questionably placed in synonymy with Parascytalocrinus hamiltonensis; and 19) Poteriocrinus burketi Worthen, 1882, nomen dubium and Zeacrinus dubius Miller and Gurley, 1890a, are placed in Incertae Sedis.

Cromyocrinus orbicularis is the oldest species of its genus extending the range of the genus downward from the Upper to the Lower Mississippian.

Cymatograptus bidextro sp. nov. from the Floian “Baltograptus deflexus” Biozone of northwest Argentina represents the oldest expansograptid with an artus type proximal development and a prosicular origin of the first theca. The species bears a variably dextral or sinistral proximal development, previously known exclusively from Tremadocian members of the Anisograptidae, but not from the Dichograptidae. The proximal development types of the Dichograptacea are shown to consist of several independently changing characters and cannot be used as phylogenetically useful descriptors. Proximal developments are more variable than expected and several independent origins of an artus type proximal development can be recognized in the Lower to Middle Ordovician.

Although enrollment has long been recognized as an important, perhaps advantageous, life posture in certain trilobites, some aspects of this phenomenon are poorly understood. Taphonomic evidence indicates that the preservation of enrolled trilobites is a two-stage process involving: 1) factors that evoked enrollment; and 2) depositional and geochemical factors that resulted in preservation of the trilobites in an enrolled condition.

The Alden Pyrite Bed, Ledyard Shale Member, Ludlowville Formation (Middle Devonian, Givetian) of western New York, a well-known stratigraphic marker bed, is formally described herein. This bed yields an extraordinary number of enrolled phacopine trilobites. This study suggests that trilobites, like certain modern arthropods, enrolled in response to inhospitable conditions, including environmental toxicity and/or rapid sediment influx. Frequency of occurrence data from the Alden Pyrite Bed and underlying and overlying beds of the Ledyard Shale indicate that the trilobites Greenops boothi (Green) and Phacops rana (Green) both enrolled in response to adverse conditions at the sediment-water interface. Prolonged adversity compelled the trilobites to remain, and eventually die, in an enrolled state. Rapid and deep burial within a fine-grained sediment precluded scavenger dismemberment and favored geochemical conditions which culminated in pyritization and preservation.

The marine Bajocian Taberna Formation of west-central Oaxaca consists mainly of shale, intercalated siltstone, and frequent iron concretions with ammonites. This formation overlies the continental Zorrillo Formation and is overlain by the continental to subcontinental Simon and Otatera formations. The best outcrops are in the area of Mixtepec and Diquiyú-Yutatio.

Two new ammonite biozones are distinguished: Duashnoceras floresi Range Zone (≃ upper Humphriesianum-lower Subfurcatum standard zones), and Parastrenoceras zapotecum Assemblage Zone (≃ Subfurcatum Standard Zone). The biogeographic affinities are principally with the Mediterranean Province, and also with both the East-Pacific Andean and North Cordilleran provinces. A high percentage of species is endemic. The Stephanoceratinae, mainly Duashnoceras, are dominant in the D. floresi Zone, which also includes Subcollina lucretia, Strigoceras (Liroxyites), Stephanoceras, Phaulostephanus, Stephanosphinctes, and Oppelia. Parastrenoceras and Leptosphinctes are dominant in the P. zapotecum Zone, whereas Oppelia and Strigoceras are less abundant.

Stephanosphinctes n. gen., type species S. buitroni n. sp., is intermediate between the Stephanoceratinae and Leptosphinctinae. The species Phaulostephanus burckhardti is also new.

A new brachiopod genus Cooperrhynchia is described for the species originally designated “Rhynchonella” schucherti Stanton, 1895, from the so-called Knoxville beds of northern California. A lectotype is selected for Cooperrhynchia schucherti (Stanton). An isolated carbonate lens within deep-water turbidites of the Great Valley Group (Jurassic–Cretaceous) yielded the brachiopod fossils near the town of Paskenta, western Sacramento Valley. The associated bivalve fauna indicates a mid late Tithonian age for the locality. Mollusks and the rhynchonellids Cooperrhynchia and Peregrinella are known from several scattered limestone lenses within Great Valley strata; collectively, these faunas and carbonate patches represent cold seep-associations that developed in forearc basins along the tectonically active northeast Pacific convergent margin during the late Mesozoic.

Mass mortality surfaces and bioclastic lags in Turonian siliceous shales of the San Rafael and La Frontera formations in Colombia have yielded two species of decapod crustaceans, Opthalmoplax spinosus new species and Pinnotheres? species indeterminate, as well as one stomatopod, Sculda sp. All represent first records for the country. Remains of the swimming carcineretid crab, Opthalmoplax spinosus, in association with fish fragments and pelagic ammonites, cover mass mortality surfaces. The occurrence suggests that the high density living population of the crabs, exploiting abundant food resources in areas of topography-controlled upwelling, was periodically reduced catastrophically, perhaps by advection of toxic trace elements or by oxygen starvation. Two other taphofacies, characterized by current oriented appendage fragments and scattered skeletal elements represent normal accumulations of fossil material in the San Rafael and La Frontera formations.

Recognition of discrete taxa is an enduring problem in the biological sciences, especially for taxonomists who work with groups that display a great degree of homeomorphy at low taxonomic levels. Selection of the type and number of characters used to make taxonomic distinctions is important because it reflects taxonomic concepts for a group as a whole. Often the validity of characters used to develop classifications is not documented and resulting classifications are therefore suspect. However, classifications can be tested for their objectivity with numerical analysis and characters can be evaluated for their relative value for making taxonomic splits by a variety of statistical techniques. In addition, evaluation of the distribution of character states can lead to insights into evolutionary histories of any group. This study provides such an analysis.

Fenestrate cryptostome Bryozoa are abundant and diverse in many upper Paleozoic rocks, and are therefore potentially highly useful for a variety of paleontologic studies. However, study of fenestrates is hampered by necessary complex preparation techniques and problems encountered with homeomorphy. In addition, inconsistent applications of inadequate methodologies have contributed to an unsatisfactory taxonomy. Results from cluster and discriminant analyses demonstrate that fenestrate species can be objectively recognized. Species distinctions are most clear when all available characters are used, although some characters are more diagnostic than others.

Results from cluster and discriminant analyses suggest that fenestrate genera represent major evolutionary shifts associated with the development of key character(s) that allowed entry into new adaptive zones. Key characters allow for an oligothetic classification of genera, which is not merely an artifact created to simplify taxonomic analysis. Diversification of species within adaptive zones resulted in a natural hierarchy of genus-level and species-level characters. Iterative evolution at the species level within separate adaptive zones resulted in a great deal of homeomorphy.

Morphometric analysis provides insights into several aspects of the paleobiology of this traditionally problematic group. Similar comprehensive studies may prove equally productive for other groups.

All species of North American marsupials from the Chadronian through Hemingfordian are reviewed. Most North American species of didelphids previously referred to Peratherium are allocated to Herpetotherium. Five species of Herpetotherium are recognized.

The Chadronian Peratherium donahoei Hough is synonymized with Herpetotherium valens (Lambe). The Orellan species Herpetotherium stevensoni Cope is resurrected and referred, along with the Chadronian Peratherium titanelix Matthew, to a new genus, Copedelphys. Both Copedelphys and Herpetotherium can be derived from known Duchesnean species of Peratherium from North America.

Two genera of peradectids are recognized, Nanodelphys McGrew and Didelphidectes Hough. Nanodelphys minutus is synonymized with “Herpetotherium” hunti Cope and a second species of Nanodelphys is recognized from the Arikareean, though not named.

Seven genera and eight species of lingulate brachiopods were recovered from the House Limestone and lower Fillmore Formation, Ibex area, Utah, USA. These strata are assigned to the upper Skullrockian Stage and lower Stairsian Stage of the Ibexian Series (Iapetognathus Conodont Zone to Low Diversity Interval) and are correlated with the Tremadocian Series of the Acado–Baltic Faunal Province. The fauna includes two new linguloid species, Spinilingula prisca and Wahwahlingula sevierensis, one new siphonotretoid species, Schizambon obtusus, and two new acrotretoid species, Eurytreta fillmorensis and Ottenbyella ibexiana. The last species is the first record of the genus in North America and suggests a correlation of the basal Fillmore Formation with the Ceratopyge Limestone in Sweden. A Siphonobolus? covered by long hollow spines may be one of the oldest siphonotretides with such ornament. This fauna and those described previously from older Utah strata document the biodiversification of the Cambrian–Ordovician lingulate brachiopods and demonstrate their potential for regional and intercontinental correlation.

Previously undescribed holes on the calyx of single specimens of the blastoids Pentremites and Cordyloblastus are circular in plan view, penetrate the test at a right angle, and are found in the interambulacral region. The same features characterize holes on 23 specimens of the Mississippian blastoid Orophocrinus. The holes are interpreted as biogenic in origin; examples of multiple complete holes on individual specimens and of incomplete holes on some blastoids indicate that the holes represent parasitism rather than predation. The similarity of these holes to those previously described in nucleocrinids and crinoids suggests that they were produced by platyceratid gastropods or closely related taxa.

We report changes of deep-sea ostracod fauna during the last 370,000 yr from the Ocean Drilling Program (ODP) Hole 704A in the South Atlantic sector of the Southern Ocean. The results show that faunal changes are coincident with glacial/interglacial-scale deep-water circulation changes, even though our dataset is relatively small and the waters are barren of ostracods until mid-MIS (Marine Isotope Stage) 5. Krithe and Poseidonamicus were dominant during the Holocene interglacial period and the latter part of MIS 5, when this site was under the influence of North Atlantic Deep Water (NADW). Conversely, Henryhowella and Legitimocythere were dominant during glacial periods, when this site was in the path of Circumpolar Deep Water (CPDW). Three new species (Aversovalva brandaoae, Poseidonamicus hisayoae, and Krithe mazziniae) are described herein. This is the first report of Quaternary glacial/interglacial scale deep-sea ostracod faunal changes in the Southern and South Atlantic Oceans, a key region for understanding Quaternary climate and deep-water circulation, although the paucity of Quaternary ostracods in this region necessitates further research.

Three new types of arthropod are described from Cambrian intertidal lithofacies of the Elk Mound Group and St. Lawrence Formation of Wisconsin and the Potsdam Group of Quebec. These arthropods are preserved ventrally in sandstone in life position and in three dimensions, allowing detailed characterization of limb morphologies, labrums, and other organs such as eyes. A taphonomic model is presented, illustrating this unusual, uncompressed, three-dimensional style of preservation. Arenosicaris inflata n. sp., from the Terreneuvian-Furongian Elk Mound Group and the Furongian St. Lawrence Formation, is the earliest unambiguous occurrence of a malacostracan phyllocarid. This 3 cm long arthropod had ovate valves, five pairs of biramous pleopods, and at least 3 pairs of thoracopods. Mosinieia macnaughtoni n. sp., a large (>10 cm long) euthycarcinoid of uncertain affinity with flattened or paddle-like appendages also occurs in Elk Mound strata. Mictomerus melochevillensis n. sp. represents a new euthycarcinoid family and is the first known non-trilobite arthropod from the middle Cambrian-Furongian Potsdam Group of Quebec. M. melochevillensis n. sp. is large (8–10+ cm long), with as many as eleven pairs of well-preserved homopodous, uniramous, non-paddle-like limbs. Both M. macnaughtoni and M. melochevillensis differ substantially from previously known euthycarcinoids in limb morphology and represent the oldest known representatives of the group. Additionally, both M. melochevillensis n. sp. and M. macnaughtoni n. sp. possess morphologies that are consistent with abundant subaerial and subaqueous Diplichnites and Protichnites trackways known from these units, suggesting that these may be the earliest land-going animals.

Givetian, Frasnian and Famennian limestones from southern China contain microfossils generally regarded as calcified algae and cyanobacteria. These are present in 61 out of 253 sampled horizons in four sections from three widely spaced localities in Guangxi and southern Guizhou. Three of the sections sampled are Givetian-Frasnian-Famennian; one section is Frasnian-Famennian. They include reef and non-reef carbonates of shallow marine platform facies. The following taxa are identified with differing degrees of confidence, and placed in algae, cyanobacteria or microproblematica. Algae: Halysis, ‘solenoporaceans’, Vermiporella. Cyanobacteria: Bevocastria, Girvanella, Hedstroemia, Subtifloria. Microproblematica: ?Chabakovia, Garwoodia, ?Issinella, Izhella, Paraepiphyton, Rothpletzella, Shuguria, ?Stenophycus, Tharama, Wetheredella. As a whole, the abundance of algae, cyanobacteria and microproblematica increases by 34% from Givetian to Frasnian, and declines by 63% in the Famennian. This secular pattern of marked Famennian decrease does not support recognition of them as “disaster forms” in the immediate aftermath of late Frasnian extinction. Nonetheless, their survival into the Famennian could indicate tolerance of environmental stress, independence of changes in food supply, morphologic plasticity, and ability to occupy a range of habitats and depths. Uncertainties concerning the affinities of the problematic taxa hinder assessment of their significance.

A new genus and species of thylacinid, Muribacinus gadiyuli, is described from Miocene deposits of Riversleigh in northwestern Queensland. Muribacinus gadiyuli shares six character states associated with carnassialisation common among thylacinids, but is uniformly less derived for each. The closest affinities of this species lie with another plesiomorphic thylacinid from Riversleigh, Nimbacinus dicksoni. Two previously recognised thylacinid synapomorphies are reconsidered in the light of new evidence. A growing body of molecular and fossil data indicates that the modern dasyurid radiation is a relatively recent phenomenon. Character analysis suggests that no reliable dental synapomorphies define the Dasyuridae at present. It is proposed that a number of plesiomorphic late Oligocene and Miocene taxa previously considered as dasyurids be regarded as Dasyuromorphia incertae sedis pending the identification of shared derived dental characters for the family, or the discovery of more complete material.

Ichthyosaurs represent one of the most highly specialized lineages of marine reptiles, but our understanding of the evolution of this group is based on specimens found at a surprisingly small number of stratigraphic intervals and localities. The Lower Jurassic (Toarcian) Posidonia Shale of southwestern Germany is one of the richest ichthyosaur-bearing formations in the world and has produced thousands of skeletons, including specimens with preserved soft tissue, and fetal remains inside the body cavity. The most abundant ichthyosaur genus in the Posidonia Shale is Stenopterygius. In spite of almost 200 years of research effort, the number of species in this genus is still a point of active disagreement in the literature. Here, bivariate and multivariate analyses are used to classify both articulated and disarticulated skeletons to the level of species, using measurement data from individual cranial and postcranial elements. Unlike previous classification attempts, this technique pinpoints ontogenetically conserved differences in size and proportion between the species, and so can be applied to adult, subadult, and neonatal specimens. Using this method, three species of Stenopterygius, S. quadriscissus, S. triscissus, and S. uniter are differentiated.

An incomplete skull of a small sphenodontian lepidosaur from the upper part of the Stormberg Group of southern Africa is referable to Clevosaurus Swinton, 1939. It is most closely related to C. bairdi from the McCoy Brook Formation (Lower Jurassic) of Nova Scotia (Canada) and C. mcgilli from the Dark Red Beds of the Lower Lufeng Formation (Lower Jurassic) of Yunnan (China). The new specimen is important because it represents the first record of Clevosaurus from the Southern Hemisphere. Like many other taxa of Early Jurassic continental tetrapods (crocodylomorph archosaurs, dinosaurs, synapsids), Clevosaurus had an apparently Pangaean distribution.

Dicoelosia occurs in two deep water benthic shelly assemblages on an Early Silurian (uppermost Aeronian, Stimulograptus sedgwickii Zone) carbonate ramp to shelf, within the 25 m thick bluish-grey mudstone of the Richardson Member in the middle Jupiter Formation, Anticosti Island, Québec. Dicoelosia dauphinensis new species is erected on the basis of its relatively large, elongate shell, with a concavo-convex lateral profile, moderately wide, planoconvex lobes and subparallel lateral margins. Dicoelosia dauphinensis first occurs in a Gotatrypa-Dicoelosia Community, in which it constitutes about 7 percent of the individuals within sampled populations. This is replaced about 2 m up section by a Resserella-Dicoelosia Community, where D. dauphinensis makes up 22 percent of the individuals preserved on single bedding planes. Subsequently, Dicoelosia becomes a rare component of the Stegerhynchus-Triplesia Community in a shallowing-upward succession of the upper Richardson Member. It is in this upper Richardson shelly community that Stimulograptus sedgwickii is locally common, together with in situ brachiopod nests of Eocoelia, Triplesia, and Lissatrypa at the upper Jupiter Cliff section. The water depth estimated for the Resserella-Dicoelosia Community is between 100-120 m, below the normal depth range of the Clorinda Community (BA5) on Anticosti, in a distal shelf setting about 80-100 km offshore from the Laurentia paleocontinent, on the west side of the Iapetus Ocean. The interpretation of water depth is based on the facts that, 1) Dicoelosia-rich communities are confined to strata, which lack shallow water sedimentological evidence such as thick calcarenites and hummocky cross stratification, 2) Dicoelosia does not occur with shallower water taxa seen in the overlying Clorinda and Stricklandia communities associated with cyclocrinitid algae, corals and stromatoporoids in the Cybèle Member, and 3) Dicoelosia occurs only in the deeper water sections of the Richardson Member, some 10-15 km basinwards from mid-shelf shallower Richardson facies of the Anticosti Basin. Thus, the Dicoelosia-rich communities are interpreted to mark a maximum flooding surface within the distal shelf to ramp Llandovery succession of Anticosti Island.

Melittosphex burmensis (Melittosphecidae) is an important apoid fossil from middle Cretaceous (~100 Ma) amber from Myanmar (Burma). Melittosphex exhibits a combination of wasp and bee features making it an important transitional form linking bees with crabronid wasps. The presence of branched hairs suggests that it was a pollen-collector and many aspects of the morphology suggest that it is more closely related to bees than to any fossil or extant group of wasps. Here we report additional morphological information on Melittosphex burmensis. This specimen remains the earliest body-fossil evidence that pollen-collecting Apoidea (bees) were present approximately 20 million years after the origin of the eudicots (~120 Ma), the major angiosperm lineage with extensive reliance on bee pollination.