On the basis of morphological and taphonomic study of a large sample population, Miaohephyton bifurcatum Steiner, emend. from the terminal Proterozoic Doushantuo Formation (600-550 Ma), South China, is interpreted as algal fragments shed from their parent thalli for reproductive or environmental reasons. Characters such as regularly dichotomous, multicellular thalli with forked tips, apical and intercalary meristematic growth, abscission structures, and possible conceptacles collectively suggest an affinity with the brown algae, in particular the order Fucales. In conjunction with reports of xanthophyte fossils in older Neoproterozoic rocks, this reinterpretation of Miaohephyton bifurcatum indicates that photosynthetic stramenopiles (chrysophytes, synurophytes, xanthophytes, phaeophytes, and diatoms; or chromophytes sensu stricto) diversified during the Neoproterozoic Era along with the red and green algae. This, in turn, suggests that the secondary endosymbiosis that gave rise to the photosynthetic stramenopiles took place relatively soon after the evolutionary transformation of cyanobacteria to rhodophyte plastids.

The Woodford Shale of south-central Oklahoma was deposited in an offshore, quiet-water, oxygen-poor setting on the southern margin of North America in assocation with other dark organic-rich shales of the Upper Devonian–Lower Carboniferous black-shale facies. The basal Woodford was deposited unconformably over lower Paleozoic carbonate strata as a south-to-north transgressive unit during the Frasnian and early Famennian. Black shales and cherts lie directly above the basal beds.

Phosphatic shales in the upper Woodford contain a conodont succession characterized by three distinct environmentally controlled faunas. The lower fauna is characterized by Palmatolepis gracilis ssp., Branmehla inornata, Bispathodus stabilis, and Pseudopolygnathus marburgensis trigonicus, indicative of the Late Devonian Lower expansa Zone to Upper praesulcata Zone. The middle fauna, which spans the Devonian–Carboniferous (D/C) boundary, is characterized by Polygnathus communis communis and species of Protognathodus. On the Lawrence uplift the D/C boundary is disconformable, as indicated by the absence of Protognathodus kockeli before the first occurrence of Siphonodella sulcata. Light-colored phosphate laminae and beds, indicative of erosion and nondeposition, and a change in biofacies from an offshore palmatolepid–bispathodid fauna to a more nearshore, palmatolepid–polygnathid–protognathodid fauna indicate higher energy conditions and a lowering of sea level associated with the boundary interval. In the eastern Arbuckle Mountains the D/C boundary is apparently conformable, marked by a green shale interval containing a Protognathodus fauna. Species of Siphonodella, indicative of an offshore setting, characterize the third and youngest fauna. The Early Carboniferous sulcata, Lower duplicata, and Upper duplicata Zones are recognized in the upper Woodford. The Woodford Shale is conformably overlain by the “pre-Welden Shale’ and its equivalents, or unconformably overlain by the lower Caney Shale (Osagean?–Meramecian) in the northern outcrop regions and the Sycamore Formation (late Osagean?–Meramecian) in the southern Arbuckle Mountains.

Modifications of primitive astogenetic patterns were central to the origin of bifoliate Peronopora. Outgroup comparison with Prasopora indicates that fundamental events in the former's origin included vertical growth of basal lamina skeleton to form the median lamina and heterochronic modifications of early and later-stage astogeny. Heterochronic modifications of early astogeny included acceleration of budding rates in the ancestrular disc, disc enlargement, and reduction of the basal expansion. Later-stage heterochronic modifications included reduction of zooecial length and width of “endozonal” growth and parallel orientation of cystiphragms about maculae. Also important were “2-D” budding in longitudinal ranges and a unique mode of secondary frond formation. Paedomorphosis resulted in constraints on zoarial form, autozooecial morphology, cystiphragm patterning, and increased colonial integration. Coordination of early and later-stage astogenetic events suggests developmental integration linked to median lamina formation. Heterochronic modifications are inferred to have been products of spatial competition in early astogeny and competitive avoidance and resource exploitation in later astogeny. Restricted biogeographic distribution and characteristics of the ancestrula suggest that the larvae of bifoliate Peronopora were nonplanktotrophic.

A shared derived suite of characters including the median lamina unite the bifoliate Peronopora clade. Results of cladistic analyses indicate that bifoliate Peronopora comprise a cohesive, statistically significant clade. Character analysis, phylogenetic results, and the restricted biogeographic distribution of bifoliate species support the hypothesis of a monophyletic bifoliate Peronopora clade of generic rank. The generic concept of Peronopora is revised and limited to bifoliate species.

The cephalon of Nephrolenellus multinodus and its stratigraphically higher sister-taxon N. geniculatus passed through the same four successive phases of development: entry into phase 2 is defined by a change from a decrease to an increase in the dynamic pattern of distance between the intergenal spine bases relative to cephalic length; entry into phase 3 is defined by the appearance of genal spines; and entry into phase 4 is defined by the effective isolation of glabellar furrow S3 from the axial furrow. Phase transitions were associated with significant changes in allometric growth patterns of the cephalon. Five instars are identified within the early development (phases 1 and 2) of N. multinodus. Despite the general similarity in cephalic ontogeny, significant interspecific differences in patterns of shape change are documented throughout phases 1, 2, and 3 of cephalic development which, with differences in rates of glabellar shape change relative to size (higher in N. multinodus) and ontogenetic loss of glabellar axial nodes (higher in N. geniculates), demonstrate that evolutionary modification to ontogeny was mosaic and complex. Stratigraphic occurrences and a temporal trend towards increased rate of glabellar axial node loss relative to size in N. geniculates are consistent with a hypothesis that N. geniculates was a direct descendant of N. multinodus. However, ontogenetic data are needed for immediate outgroups of Nephrolenellus to determine whether two potential autapomorphies of N. multinodus, which refute such a hypothesis, are indeed unique to this taxon. Nephrolenellus jasperensis is recognized as a junior synonym of N. multinodus.

Although the burrows and trails in the Upper Ordovician rocks around Cincinnati, Ohio, have been fully documented and are well known (Osgood, 1970), comparatively little attention has been paid to the borers. Nevertheless, borers are very common in a variety of hard substrates in these rocks. These substrates include the skeletons of bryozoans, corals, and stromatoporoids (Palmer and Wilson, 1988), as well as cobbles and hardgrounds (Palmer, 1982; Wilson, 1985). By far the most common type of boring is the elongate tube Trypanites, which could have been made by a variety of filter-feeding worms. Trypanites is common on hard substrates throughout the lower Paleozoic (Palmer, 1982).

A comparative analysis of the postcranial skeletal morphology of three species of pakicetid cetaceans provides new insights into their locomotor behavior. in gross morphology, they are similar to their smaller early artiodactyl relatives, lacking obvious signs of their transition to an aquatic niche. Features linking them are related to a cursorial adaptation centered in the reduction of joint mobility to the parasagittal plane, evident in both the elbow and the ankle. in addition to cursorial features of the limbs, the earliest whales and early artiodactyls both possess a long, stable lumbus and robust tails. the three pakicetid genera can be distinguished by size, proportion, and details of articular morphology. However, all pakicetid postcrania bear microstructural specializations commensurate with aquatic locomotion, and incompatible with cursoriality. the most striking modification is the presence of systemic increased bone density, likely used as skeletal ballast. When both postcranial morphology and microstructure are considered, it can be concluded that pakicetid cetaceans were highly adapted for an aquatic niche. As in several extant semiaquatic taxa, the pakicetid tail undoubtedly contributed to its locomotor repertoire, whether in propulsion or stabilization.

A large ichthyosaur from the Los Molles Formation (Early Bajocian) of the Neuquén Basin, Northwestern Patagonia, Argentina, represents a new genus and species, Mollesaurus periallus. The holotype of M. periallus new species represents, along with the type of Chacaicosaurus cayi that was found at the same locality, the only diagnostic ichthyosaur specimens from the Aalenian-Bathonian interval.

The High Bridge Group (Middle Ordovician), and the Lexington Limestone and Clays Ferry Formation (Middle and Upper Ordovician), of central Kentucky contain a diverse fossil invertebrate fauna, including cryptostome ptilodictyoids, the so-called “bifoliates,” as a distinctive element. The ptilodictyoid bryozoans there include nine species of six genera Escharopora, Graptodictya, Phyllodictya, Stictopora, Trigonodictya, and new genus Orectodictya in two families Ptilodictyidae and Rhinidictyidae. Three species are new: Escharopora eparmata, Trigonodictya cirrita, and Orectodictya pansa. Most of the species are closely related to ptilodictyoids occurring in the Middle Ordovician of New York and Minnesota. In Kentucky, Escharopora, Stictopora, and Trigonodictya occur in the oldest rocks exposed, and thus include the oldest bryozoans found in Kentucky. The stratigraphic distribution of ptilodictyoids in Kentucky reflects the disconformable contact between the Tyrone Limestone (High Bridge Group) and the overlying Lexington Limestone.

The family Palaeothentidae contains some of the dentally more specialized of the small-bodied marsupials of South America and was a clade almost equivalent with the Abderitidae in having been the most abundant caenolestoids. They were unquestionably the most diverse, containing two subfamilies, nine genera, and 19 species, with a distribution ranging from Colombia to Tierra del Fuego. The best and most continuous record of the Palaeothentidae is from Patagonian Argentina where eight genera and 17 species are recognized. There, the Palaeothentidae ranged in age from the Deseadan (later Oligocene) through the late Santacrucian (middle Miocene—the Santacrucian record lasting from about 19.4 m.y. to considerably less than 16.05 m.y. before the present). The family appears to have survived longer in Colombia. The palaeothentine Palaeothentes boliviensis (Bolivia) and the incertae sedis genus and species Hondathentes cazador (Colombia) are the only taxa restricted to an extra-Argentine distribution.

Two palaeothentid subfamilies are recognized. The subfamily Acdestinae is new and is erected to accommodate four genera and five species of herbivorous to frugivorous palaeothentids known from the Deseadan through the middle–late Santacrucian. Three of those genera are new (Acdestoides, Acdestodon, and Trelewthentes), as are three acdestine species placed in the genera Acdestodon, Trelewthentes, and Acdestis. The largely faunivorous Palaeothentinae includes four genera and 13 species; the genera Propalaeothentes and Carlothentes are new and new species are described for the genera Propalaeothentes (2) and Palaeothentes (3). Carlothentes is named for Ameghino's Deseadan species Epanorthus chubutensis, and Ameghino's genus Pilchenia is resurrected to accommodate Deseadan P. lucina. New species include: Acdestodon bonapartei, Trelewthentes rothi, Acdestis lemairei, Palaeothentes marshalli, P. migueli, P. pascuali, and Propalaeothentes hatcheri.

The Palaeothentinae contains more generalized palaeothentid species than does the Acdestinae, but also includes some very specialized forms. The most generalized known palaeothentid is the Colombian Hondathentes cazador. Both the Acdestinae and Palaeothentinae have large- and small-bodied species; Palaeothentes aratae was the largest palaeothentid (about 550 g), and P. pascuali n. sp. the smallest (about 50 g). The oldest known members of both subfamilies consist of five of the six largest palaeothentids.

The evolutionary history of the Palaeothentidae is complicated by thick sequences containing no fossils, several lacunae in sequences that yield fossils, and a continent-wide distribution of localities. By far the densest and most continuous record of the family exists in the coastal Santa Cruz Formation of Patagonian Argentina. Three major clades exist within the Palaeothentidae: 1) the incertae sedis species Hondathentes cazador; 2) the Acdestinae; and 3) the Palaeothentinae (including the new genus Propalaeothentes). The evolution of dental characters in these clades is documented with the aid of 719 new specimens (about 80% of the hypodigm of the family), most of which (about 90% of the new specimens) have precise stratigraphic data.

Biostratigraphic study of the new samples was assisted by a new technique of temporal analysis of paleosols and by radiometric age determinations, the latter indicating that the upper part of the Pinturas Formation (16.6 Ma) is older than the lower part of the Santa Cruz Formation (16.4 Ma) and that the top of the marine Monte León Formation (Grupo Patagonica) is older than either (19.4 Ma).

Fifty-two gnathic and dental characters were used to identify the taxonomy and to reconstruct the phylogeny of the Palaeothentidae. Analysis of sequencing of appearances of derived characters documents rampant convergences at all taxonomic levels and considerable phenotypic plasticity (variable percent representation of different mutable character morphs) in the organization of the palaeothentid dentition. Certain highly generalized character states survive for the duration of the family in some lineages, whereas others are phenotypically lost for a time and then reappear as a minor percentage of character variability. In general, replacement faunas of palaeothentids were morphologically more generalized than their antecedent forms. The high rate of character mutability and the survival and reappearance of generalized dental characters in the Palaeothentidae were probably related to massive events of pyroclastic deposition that periodically caused at least local extinctions of small mammal populations throughout the duration of the Patagonian middle Tertiary. Dental character regression indicates that palaeothentids arose prior to the Deseadan from a relatively large-bodied marsupial having generalized tribosphenic molars with more or less bunodont cusps; probably an unknown member of the Didelphidae.

A new actinopterygian, Cuneognathus gardineri new genus and species, is described from the Devonian (Famennian) Obrutschew Bjerg Formation of East Greenland on the basis of multiple incomplete specimens. Cuneognathus most closely resembles Limnomis from the Famennian Catskill Formation of Pennsylvania, and, like that taxon, is known exclusively from freshwater deposits. A cladistic analysis with an ingroup of 13 actinopterygians and an outgroup of five sarcopterygians explores the relationships between the new genus and some of its better-known Devonian contemporaries, and recovers the same four topologies regardless of the implementation of limited character ordering. Cheirolepis is resolved as the most basal of well-known Devonian actinopterygians, consistent with a majority of previous studies. A novel sister-group relationship between Howqualepis and Tegeolepis is found in all trees. Disagreement between the most parsimonious cladograms is concentrated in a clade whose members are often informally referred to as ‘stegotrachelids.’ Cuneognathus and Limnomis are resolved as sister taxa within this large radiation along with the pairings of Moythomasia dugaringa plus M. nitida and Krasnoyarichthys plus Stegotrachelus. the arrangement of taxa is conserved when the enigmatic Dialipina is added to the analysis, although the reconstructed position of that genus above both Cheirolepis and Osorioichthys seems improbable. Our scheme of relationships suggests that actinopterygians invaded freshwater environments at least four times during the Devonian, while age constraints indicate that many of the cladogenic events between ingroup taxa included in this study occurred during or before the Givetian.

Among invertebrates and both in modern and ancient marine environments, certain echinoderms have been and are some of the most active and widespread bioturbators and bioeroders. Bioturbation and/or bioerosion of regular and irregular echinoids, starfish, brittle stars, sea cucumbers and crinoids are known from modern settings, and some of the resulting traces have their counterparts in the fossil record. By contrast, surficial trails or trackways produced by other modern echinoderms, e.g., sand dollars, exhibit a lower preservation rate and have not yet been identified in the fossil record. In addition, the unique features of the echinoderm skeleton (e.g., composition, rapid growth, multi-element architecture, etc.) may promote the production of related traces produced by the reutilization of echinoderm ossicles (e.g., burrow lining), predation (e.g., borings), or parasitism (e.g., swellings or cysts). Finally, the skeletal robustness of some echinoids may promote their post mortum use as benthic islands for the settlement of hard-substrate dwellers.

We summarize faunal changes through the thickest and one of the most complete records of terrestrial vertebrates spanning Lancian (∼latest Cretaceous) and Puercan (∼earliest Paleocene) ages, the type Ferris Formation in the Hanna Basin, southern Wyoming. Observed faunal changes predate tectonic definition of local Laramide basins. Nonmammalian vertebrates exhibit no major changes in taxonomic composition below the Lancian-Puercan boundary; diversity of non-avian dinosaurs remains high within uppermost levels of the Lancian section. Nevertheless, dinosaurian extinction was not necessarily “catastrophic” within a biologically relevant interval. Primitive condylarths appear locally above the highest known dinosaurs, probably as immigrants. At least in this part of the North American western interior, the first evolutionary radiation of condylarths was subsequent to the last appearance of dinosaurs, not synchronous with or prior to it. Niche-partitioning among condylarths is first recorded near the boundary between Puercan Interval-zones Pu1 and Pu2 (early and middle Puercan time, respectively), by which time the first great mammalian diversification of the Cenozoic had begun. Major experimentations in dental morphology and increasing ranges of body sizes had developed within 400,000 years of the Lancian-Puercan boundary. We recognize no evidence suggesting that placental mammals were “recovering” from events that led to demise of the dinosaurs. The true diversity of marsupials and condylarths precisely at the Cretaceous-Tertiary boundary, throughout the western interior, remains unknown. We cannot, therefore, evaluate extensiveness of competition, if any, at that time among members of the two groups.

Long-stemmed eocrinoids are limited to two species in the basal Middle Cambrian Kaili Biota, which occupies the middle portion of the Kaili Formation, Taijiang County, Guizhou Province, China. the Kaili Biota contains preserved soft-bodied organisms shared with either the Chengjiang Fauna (Southwest China) or the Burgess Shale Fauna (British Columbia) or with both. Echinoderms are preserved as limonitic external molds that produce excellent latex casts. Sinoeocrinus lui Zhao et al., 1994 has a complex ontogenetic development, which is described in terms of morphology of holdfast, number of thecal plate circlets, addition and morphology of thecal pores, ambulacral arrangement, and number of brachioles relative to thecal height. Because of the complex ontogeny the following species are now seen to be synonymous with S. lui: lui. S. curtobrachiolus Zhao et al., 1994; S. lepidus Zhao et al., 1994; S. longus Zhao et al., 1994; S. minus Zhao et al., 1994; Paragogia globosa Zhao et al., 1994; and Curtoeocrinus guizhouensis Zhao et al., 1994. A second and rare eocrinoid of undetermined familial and ordinal placement, Balangicystis rotundus n. gen. and sp., has an unusually long holdfast and poreless thecal plates with prominent radial ridges. Sinoeocrinus lui and Balangicystis rotundus inhabited the outer shelf in disaerobic fine-grained shales and mudstones. Megascopic infauna in their community is not present.

Naticid gastropods of the Chesapeake Group of Maryland, like extant naticids, apparently were cannibalistic. This cannibalism did not result from the absence of bivalve prey or from the ineptitude of the predator, as some previous authors have suggested. Instead, predation on Chesapeake Group naticids was a predictable result of prey selection to maximize energy gain per foraging time.

This study examines predation on Lunatia heros (530 specimens) and Polinices duplicatus (340 specimens) from the St. Marys Formation of the Chesapeake Group. Predation on naticids displayed the same characteristics as predation on bivalve prey, including selectivity of prey size and drillhole site. The two naticid species were differentially attacked, based on their relative cost-benefit ratios and escape sizes. Cannibalism is not anomalous; it is the expected result of selective predation, and is inhibited primarily by the high mobility of naticid prey.

Phylogenetic taxonomy, that component of phylogenetic systematics concerned with the verbal representation (rather than the reconstruction or estimation) of phylogenetic relationships, was developed by de Queiroz and Gauthier (1990, 1992, 1994). Under phylogenetic taxonomy, all taxon names are names of clades (i.e., an ancestor and all of that ancestor's descendants). De Queiroz and Gauthier (1990, 1992, 1994) described three possible ways of denning clade names within the phylogenetic taxonomic system: 1) node-based definitions (Figure 1.1), of the form “the most recent common ancestor of Taxon A and Taxon B, and all of that ancestor's descendants”; 2) stem-based definitions (Figure 1.2), of the form “Taxon A and all taxa sharing a more recent common ancestor with Taxon A than with Taxon B”; and 3) apomorphy-based definitions (Figure 1.3), of the form “the first taxon with derived character X and all of that ancestor's descendants.” Bryant (1994) noted that, while the first two definition types will always be stable, apomorphy-based definitions are potentially confusing if that derived character is found to occur in more than one lineage (i.e., is homoplastic). Under the phylogenetic system of taxonomy, definitions of taxon names are independent with respect to previous diagnosis (as particular character states may be found to occur in other lineages or in more inclusive clades) and composition (as particular member taxa may subsequently be found to lie outside the defined clade boundary). This paper is the initial work in an ongoing study by Holtz and Padian (1995, in preparation) to clarify the phylogenetic taxonomy of major clades of theropods and related taxa.

Abundant tubular macrofossils occur in finely laminated siltstones and shales of the 548–542 Ma Schwarzrand Subgroup, Nama Group, Namibia. The Nama tubes occur in both the Vingerbreek and Feldschuhhorn members commonly in dense populations and always in fine-grained, lower shore-face lithologies deposited below fair-weather wave base. The tubes are preserved mostly as compressed casts and molds that range in width from 0.6 to 2.1 mm; apparently incomplete specimens reach lengths up to 10 cm. All specimens show sinuous bending and occasional brittle fracture, indicating an original construction of strong but flexible organic matter. Feldschuhhorn specimens preserve fine longitudinal pleats or folds that record pliant organic walls, but the older Vingerbreek populations do not. Similarly, some specimens in the Feldschuhhorn Member display branching, while Vingerbreek tubes do not. The abundant Feldschuhhorn tubes are assigned to the widespread Ediacaran problematicum Vendotaenia antiqua; however, the distinctive Vingerbreek population remains in open nomenclature. The most abundant fossils in Nama rocks, these tubes resemble populations in Ediacaran successions from Russia, China, Spain, and elsewhere. Beyond their local importance, then, such tubes may turn out to be the most abundant record of Ediacaran life.

A Campanian fish assemblage is described from the uppermost Blufftown Formation in western Georgia. Fifteen chondrichthyan and eight osteichthyan taxa are identified, virtually all for the first time from the region. The study area represented a transitional zone between the Atlantic and eastern Gulf of Mexico Coastal Plain Provinces during the Late Cretaceous, and shows faunal relationships with both.

A comprehensive, high resolution stratigraphic database of fusulinoidean foraminifers reveals that this group of protists suffered extreme losses during the Guadalupian extinction. Most species (88%) were eliminated gradually over the course of 9 myr during the Wordian and Capitanian ages. A pulse of greatly elevated per capita extinction frequency occurred during the last million years of the Capitanian (260–259 Ma). Contrary to prevailing opinion, the end-Capitanian event did not preferentially eliminate large, morphologically complex species in the families Schwagerinidae and Neoschwagerinidae, because most species in those families were already extinct. Rather, 69 percent of the species eliminated at the end of the Capitanian were small, morphologically conservative representatives of the Ozawainellidae, Schubertellidae and Staffellidae. Survivors from these families comprised the low-diversity association of Wuchiapingian fusulinoideans. Schubertellids, and to a lesser extent ozawainellids, diversified in the late Wuchiapingian and Changhsingian ages before the final demise of fusulinoideans during the end-Permian mass extinction. The Wordian–Capitanian fusulinoidean attrition might have been caused by photosymbiont loss and habitat reduction stemming from an interval of global cooling termed the Kamura event (∼265–259.5 Ma), although the onset of fusulinoidean diversity decline predates geochemical evidence for the beginning of the Kamura event by ∼3 myr. The end-Capitanian extinction pulse might reflect environmental deterioration from the combined effects of global cooling, Emeishan effusive volcanism and sea-level lowstand.

Microscopic phosphatic scales are found in limestones and cherts from the 812–717 million year old Fifteenmile Group of the Yukon Territory. These enigmatic microfossils, which to date have not been identified in any other locality, display a diversity of intricate morphologies. Here we describe six new genera containing 17 new species of scale microfossils obtained from macerated limestone. We also revise existing taxa described originally from chert thin sections and now additionally freed from limestone by acid dissolution. New taxa described here are: Archaeoxybaphon serratacapacis n. sp., Archeoxybaphon serratapusilla n. sp., Paleoscutula inornata n. gen. n. sp., Paleoscutula serrata n. gen. n. sp., Paleoscutula convocationis n. gen n. sp., Hexacatillus allmonii n. gen. n. sp., Hexacatillus retetantillus n. sp., Quadrireticulum allisoniae n. gen. n. sp., Quadrireticulum palmaspinosum n. gen. n. sp., Circidentatus pistricis n. gen. n. sp., Circidentatus variodentatus n. gen. n. sp., Ospercapatera awramikii n. gen. n. sp., Circitorquis soccus n. gen. n. sp., Paleohexadictyon alexandrae n. sp., Paleomegasquama arctoa n. sp., Petasisquama petasus n. sp., and Thorakidictyon circireticulum n. gen. n. sp. Taxa described or amended here are Characodictyon skolopium Allison and Hilgert, 1986, Paleohexadictyon myriotrematum Allison and Hilgert, 1986, Archeoxybaphon polykeramoides (Allison and Hilgert, 1986) emend., Paleohexadictyon litosum (Allison and Hilgert, 1986) emend., and Thorakidictyon myriocanthum (Allison and Hilgert, 1986) n. comb. Many eukaryotic clades include species with surficial scales but none provides a close morphological analog to the Fifteenmile scales. Nonetheless, comparative and functional morphology suggest that the diversification of heavily armored and morphologically complex cell-coverings records a changing ecological landscape in Neoproterozoic seas.

The Upper Dharmaram Formation (Lower Jurassic, Sinemurian) of India has yielded three sauropodomorph dinosaurs, two new taxa and an indeterminate one. Lamplughsaura dharmaramensis n. gen. and sp., represented by several partial skeletons, is a heavily built quadrupedal form (body length ~10 m). Autapomorphies include teeth with strongly emarginated distal edge; caudal cervical neural spines bearing a vertically oriented ligamentous furrow on cranial and caudal surfaces and a transversely expanded spine table; caudal neural spines bearing a craniodorsally directed spur (proximal caudal vertebrae) or a large process (midcaudal vertebrae); caudal neural spines shorter than transverse processes so former lost first in passing along tail; and a plesiomorphy that is the nontrenchant form of manual ungual I. The Indian dinosaurs were coded for two recent datamatrices for basal sauropodomorphs. The results of this preliminary analysis indicate that Lamplughsaura is either a basal Sauropoda or, less likely, based on Templeton's test, a stem sauropodomorph. The second large form, represented by the proximal half of a femur, is a sauropodomorph that is more derived than Saturnalia (Brazil) and Thecodontosaurus (Great Britain) from the Upper Triassic. This is also true for the smaller (body length ~4 m as adult) Pradhania gracilis n. gen. and sp. which lies outside of the Sauropoda + Plateosauria clade, so it is definitely a stem sauropodomorph. Pradhania is known from fragmentary material; an autapomorphy is the very prominent medial longitudinal ridge on the maxilla.