The Hanneh Member (Cambrian Stage 5) of the Burj Formation and the Umm Ishrin Formation of Jordan represent a transgressive-regressive succession that contains twenty-eight ichnotaxa, including vertical burrows (Arenicolites isp., Diplocraterion isp., Gyrolithes polonicus, Rosselia isp., Skolithos linearis, escape trace fossils), horizontal simple burrows and trails (Archaeonassa fossulata, Gordia marina, Helminthoidichnites tenuis, Palaeophycus tubularis, Planolites beverleyensis, P. montanus), plug-shaped burrows (Bergaueria sucta), horizontal branched burrows (Asterosoma isp., Phycodes isp., Treptichnus cf. T. pedum), bilobate structures (various ichnospecies of Cruziana and Rusophycus), and trackways and scratch marks (Diplichnites isp., Dimorphichnus cf. D. obliquus, Monomorphichnus isp.). Eleven trace-fossil assemblages are identified. The Arenicolites isp. and Diplocraterion isp. assemblages occur in transgressive tidal dunes and bars whereas the Rosselia isp. assemblage characterizes areas between tidal dunes. The Cruziana salomonis assemblage reflects a wide variety of environmental settings including channels within tidal-bar complexes, bottomsets of tidal dunes, and interdune areas. The Gordia marina assemblage is present between dune patches. The Gyrolithes polonicus assemblage penetrates into firmground mudstone below the maximum flooding surface. The Bergaueria sucta, Archaeonassa fossulata, Rusophycus aegypticus and Cruziana problematica assemblages occur in different subenvironments of the progradational delta. Cruziana salomonis and Rusophycus burjensis, originally considered indicative of an early Cambrian age, are actually middle Cambrian in their type locality. Occurrences of Cruziana jordanica and Rusophycus aegypticus provide evidence that these ichnospecies are of the same age in Jordan and may co-exist in terms of stratigraphic distribution with C. salomonis and R. burjensis.

The assemblage of lagenide foraminifers in uppermost Permian rocks of the central Taurides consists of 22 species in 16 genera, including the new species Rectostipulina pentamerata, plus additional unidentified elements. Of these, only two identifiable species in “Nodosaria” and indeterminate syzraniids survived the end-Permian mass extinction. The last occurrences of most taxa fall within the upper half-meter of the Permian System, a pattern consistent with abrupt extinction when tested for the Signor-Lipps effect. Permian survivors are joined locally in the Lower Triassic and lower Middle Triassic by three additional species. Globally, lagenide species diversity remained low until latest Anisian time, and probably did not reach pre-extinction levels until Late Triassic or Early Jurassic time. The survival of the lagenide clade, in contrast to the complete elimination of fusulinoidean fusulinides, may be linked to the lagenides' comparatively greater paleoenvironmental tolerances and wider paleogeographic distribution. Evaluation of lagenide extinction and survival across the Permian–Triassic boundary in the central Taurides is complicated by a facies change from bioclastic wackestones and packstones to oolitic grainstones near the top of the Permian, and by the development of variably dolomitized and pyritic stromatolites and overlying oolites in the lowest Triassic. The stromatolitic and oolitic Lower Triassic lithologies represent a sedimentologic response to the end-Permian mass extinction and unusual Early Triassic marine environments. Stromatolites likely became established as disaster forms in an ecologically permissive period that lacked normal marine grazing and bioturbating benthos. Their calcification and preservation may have been promoted by high carbonate saturation levels. Oolites, which are found in recurring facies associations with stromatolites and other anachronistic carbonates in Lower Triassic rocks throughout the Tethyan embayment, probably also formed in response to elevated saturation levels and the absence of a skeletal sink for carbonate.

Universal elemental homology (UEH) is used to establish homology of thecal plates and elements of the ambulacral system among clades of stemmed echinoderms by placing these structures into a testable hypothesis of homology. Here UEH is used to explore hypotheses of homology in blastoids, coronoids, Lysocystites, hemicosmitoids, and glyptocystitoids. This new approach to analyze homology is particularly powerful in understanding the nature of the thecal plates of blastoids and how they relate to other taxa in a common nomenclatural lexicon. In blastoids, deltoids are interpreted as oral plates that are homologues to oral plates of glyptocystitoids and hemicosmitoids whereas side plates are interpreted to be ambulacral floor plates. Thecal plates are homologous among blastoids, coronoids and Lysocystites but these morphologies cannot be reconciled with plate circlets of glyptocystitoids and hemicosmitoids. A phylogenetic analysis of these taxa presents the origin of blastoids as sister taxon of coronoids within a testable series of homologies.

Although echinoderm debris is locally common, articulated specimens are rare in Late Cambrian rocks from the Great Basin and Rocky Mountains of the western United States and are mostly associated with hardgrounds. The fauna, including cornute stylophorans, trachelocrinid eocrinoids, solute homoiosteleans, and rare edrioasteroids, includes several members of the archaic Cambrian Evolutionary Fauna, which had already passed its maximum diversity for echinoderms. In addition to the low diversity, articulated specimen abundance is very low, averaging only about one-tenth that found in overlying Lower Ordovician units. The transition between the Cambrian and Paleozoic Evolutionary Faunas for echinoderms in North America apparently occurred rapidly very close to the Cambrian-Ordovician boundary, because no unequivocal examples of the Paleozoic fauna (such as crinoids, glyptocystitid rhombiferans, asteroids, or echinoids) were found in the Late Cambrian sections.

New taxa include several cothurnocystid stylophorans assigned to Acuticarpus delticus, new genus and species, Acuticarpus? republicensis, new species, and Archaeocothurnus goshutensis, new genus and species; Scotiaecystis? species, a poorly preserved cornute stylophoran with lamellipores; Minervaecystis? species, a fragmentary solute homoiostelean based on several steles; Tatonkacystis codyensis, new genus and species, a well-preserved trachelocrinid eocrinoid with five unbranched arms bearing numerous brachioles; an unnamed, poorly preserved, epispire-bearing eocrinoid; an unnamed, poorly preserved, globular eocrinoid? lacking epispires; and an unnamed, heavily weathered, edrioasterid edrioasteroid. Nearly all holdfasts found in these Upper Cambrian units are single-piece blastozoan types, probably belonging to trachelocrinid and other eocrinoids. Distinctive columnals and thecal plates of several additional undescribed eocrinoids and other echinoderms were locally abundant and are also described.

Repaired shell injuries are reported in 11 specimens including six genera and eight species of gastropods from the upper Middle Ordovician (Caradoc) Kullsberg Limestone and the Upper Ordovician (Ashgill) Boda Limestone, Siljan district, Sweden. The specimens are of different sizes and morphologies, including one isostrophic, three low-spired, and six moderately high-spired turbinate forms. Single and repeated episodes of shell damage and subsequent repair are preserved, the breaks ranging from simple arcuate or scalloped fractures to removal of large sections of the apertural margin. Both early and late growth stages show damage, but the injuries are usually restricted to only one whorl. No shell repairs were discovered on the 65 more or less complete specimens of the subulitids, although the smooth shell makes observation difficult. Injuries in the Siljan samples are found in both microgastropods and large specimens, but the sample is too small for meaningful quantification. The shell repair frequency is about 7 percent, based on examination of 404 specimens (54 from Kullsberg Limestone and 350 from Boda Limestone). Most of the repaired injuries are attributed to failed predation, adding significantly to the Lower Paleozoic documentation of predation on gastropods. The gastropod shells are morphologically weak by modern standards, but do show some architectural strengthening features such as narrow apertures, collabral or spiral threads, and other ornamentation. The identity of the predator(s) is unknown.

Paleobiogeographic patterns of decapod crustaceans from the Southern Hemisphere, based upon 441 species-level records arrayed in 154 genera, document global patterns of distribution that can be compared to those previously published on decapods from the North Pacific and Central American regions. All known records of decapods from the Southern Hemisphere spanning the Early Triassic to Pleistocene have been compiled, nearly all have been personally verified, and patterns of origin and distribution have been interpreted. Interchange between hemispheres, including amphitropical and bipolar distributions, are recognized from Jurassic to post–Miocene time. The high southern latitudes was a site of origin of several generic-level taxa during the Jurassic through Eocene and many of these taxa have been identified in subsequent times in lower latitude regions in shallow- and deepwater environments in both hemispheres. The isolation of Antarctica due to ocean currents significantly diminished the role of the high southern latitudes as an area of origin for decapods. The Tethys was an important dispersal pathway for decapods during the Cretaceous through early Miocene. Endemism was high during the Eocene, similar to the North Pacific and Central America. The magnitude of the Cretaceous/Paleogene extinction event on the Southern Hemisphere decapod fauna was not profound; most Cretaceous extinctions seem to have occurred well before the end of the Cretaceous, and 85% of the Cretaceous families are known from the Paleogene in the Southern Hemisphere taxa.

Two types of evidence for insect ovipositional activity (i.e., actual egg chorions and ovipositional damage) occur on Nilssoniopteris (bennettitalean foliage) leaf cuticles from the Carnian of Austria and provide a rare direct insight into insect egg morphology and oviposition in the Late Triassic. the egg chorions have exclusively been found on N. haidingeri leaves, where they are attached to the outer surface of the abaxial cuticle; one specimen suggests that the eggs were arranged in circles. It is impossible at present to determine the affinities of the eggs; possible producers may be beetles, dragonflies, sawflies, or other allied basal Hymenoptera. Ovipositional damage occurs on N. angustior leaves in the form of lenticular egg impressions surrounded by a narrow, elevated margin. the impressions are visible on the ad- and abaxial cuticle, and coincide when both cuticles are superimposed, which indicates that the eggs producing these impressions were injected into the interior of the leaf. Producers of eggs that may have caused these damages are perhaps dragonflies or damselflies. the restricted occurrence of the two types of ovipositional activity suggests that some kind of host specificity existed, perhaps related to specific preferences in larval diet.

Abundant, well-preserved specimens of a new peltocystidan mitrate carpoid, Jaekelocarpus oklahomensis n. gen. and sp., have been discovered in the Pennsylvanian (Morrowan Series) Gene Autry Shale Member, Golf Course Formation, in southern Oklahoma. The new carpoid postdates the youngest previously known carpoids (Middle Devonian) by about 65 million years. It is characterized by a small (to 4 mm in length) globose theca composed of six plates: two large adaulacophorals, two large marginals, and two relatively small plates that frame the main thecal orifice. One of the plates at the orifice bears a single stout spine. The theca and plates that comprise the theca display a high degree of bilateral symmetry. In contrast, the styloid has an asymmetrical array of spines and blades.

We hypothesize that most mitrates, including this one, were adapted to an infaunal life mode. The streamlined, generally symmetrical body shape is an adaptation to moving on or through the substrate. Spines and blades on the lower surface of the styloid and proximal aulacophore are inferred to be adaptations for gripping the substrate as the animal pulled itself backwards (aulacophore first). The main thecal orifice opposite the aulacophore was the site of both mouth and anus. Evidence for a sluggish, epifaunal life mode in the cornute carpoids includes the typically flattened, asymmetrical body, the presence of downward projecting spines and knobs on the marginal thecal plates of many species, and the specialized thecal pores and slits that faced away from the substrate.

Fossil land mammals were collected by G. G. Simpson in 1933–1934 at and near the Tapera de López in central Chubut Province, Patagonia, southern Argentina, from rocks now mapped as the Sarmiento Formation. These fossils are assigned to land mammal faunas of Casamayoran (Early Eocene), Mustersan (Middle Eocene), and Deseadan (late Early Oligocene through Early Miocene) age.

40K-40Ar age determinations of eight basalt and two tuff units associated with the Deseadan age local fauna at Scarritt Pocket establish a geochronologic framework that calibrates the biostratigraphic record at this locality. The radioisotope dates obtained at Scarritt Pocket range from 23.4 Ma to about 21.0 Ma, and equate with earliest Miocene time. The Scarritt Pocket local fauna is the youngest dated Deseadan age fauna yet known in South America.

Seven other localities have, or were reputed to have, local faunas of Deseadan age associated with dated volcanic units. Six of these localities are in Argentina (Gran Barranca, Cerro Blanco, Valle Hermoso, Pico Truncado, Cañadón Hondo, Quebrada Fiera de Malargüe) and one in Bolivia (Estratos Salla in the Salla-Luribay Basin). The stratigraphic relationships of the volcanic units with these local faunas is discussed, and the taxonomic content of each is reassessed.

The Deseadan Land Mammal Age is defined by the earliest record of the land mammal genus Pyrotherium, which is from below a basalt dated at 33.6 Ma at Pico Truncado. Other early records of Pyrotherium occur below basalts dated at about 29 Ma at the Gran Barranca and Valle Hermoso, and from a 28.5 Ma level of the Estratos Salla. Thus, the lower boundary for Deseadan time is about 34 Ma.

The youngest record of Pyrotherium is in the upper levels of the Estratos Salla dated at about 24 Ma. However, the Scarritt Pocket local fauna, which lacks Pyrotherium, permits placement of the upper boundary for Deseadan time at about 21.0 Ma. Late Deseadan time is surely, and the end of Deseadan time is apparently, marked by the last record of such groups as Proborhyaeninae (Proborhyaena), Rhynchippinae (Rhynchippus), Archaeohyracidae (Archaeohyrax), and the genera Platypittamys (Octodontidae), Scarrittia (Leontiniidae), Propachyrucos and Prohegetotherium (Hegetotheriidae), and Argyrohyrax (Interatheriidae), as these taxa are recorded in the Scarritt Pocket local fauna. Thus, Deseadan time extends from about 34.0 Ma to about 21.0 Ma, making it the Land Mammal Age with the longest known duration in South America.

Discovery of avicularium-like polymorphs in Wilbertopora mutabilis Cheetham, 1954 has provided not only a new opportunity for revising the genus Wilbertopora Cheetham, 1954, but also a more detailed basis for documenting the series of morphological changes by which avicularia differentiated from ordinary feeding zooids in what appears to be the first occurrence of these characteristic cheilostome bryozoan structures in the fossil record.

Eighteen of a total 60 quantitative characters measured on avicularia and ordinary and ovicell-bearing autozooids were sufficient to distinguish eight species of Wilbertopora by discriminant function analysis of zooid data from 93 colonies from the mid-Cretaceous (Albian-Cenomanian) Washita Group in northeastern Texas and southeastern Oklahoma. Eighteen of a total of 20 of the quantitative characters that could be statistically coded for cladistic analysis proved to be informative with respect to parsimony, providing two maximally parsimonious trees for the eight species. Two-thirds of the diagnostic characters involve avicularia. An additional 55 colonies too poorly preserved for morphometric analysis could then be assigned to species qualitatively, with 170 more colonies lacking species-diagnostic characters.

The cladistic trees strongly suggest that most or all of the species diverged before the end of the Albian, but stratigraphic resolution is insufficient to test this hypothesis. Nevertheless, the series of morphological changes differentiating avicularia from ordinary autozooids in these species, based on the cladistic relationships, is highly significant statistically, and may be a pattern later repeated in other cheilostomes.

Wilbertopora and W. mutabilis are emended, and seven new species are described: W. listokinae, W. tappanae, W. spatulifera, W. attenuata, W. improcera, W. acuminata, and W. hoadleyae.

Living ectocochliate cephalopods have long been thought to be restricted to a single genus, Nautilus Linnaeus, 1758, comprising five or six extant species. The shells of two species, N. scrobiculatus Lightfoot, 1786, and N. perforatus Conrad, 1847, are quite distinct, but no soft-parts were known until 1984, when N. scrobiculatus was seen alive for the first time. Dissections show that significant anatomical differences exist between N. scrobiculatus and other Nautilus species, including differences in gill morphology and details of the male reproductive system. These differences, along with phylogenetic analysis of extant and selected fossil nautiloid species, indicate that N. scrobiculatus, and N. perforatus should be distinguished from Nautilus as a newly defined genus, Allonautilus. This analysis contradicts previous phylogenies proposed for the Nautilida, which placed Nautilus as the last-evolved member of the order. We surmise that Allonautilus is a descendent of Nautilus, that the latter is paraphyletic, and first evolved in the Mesozoic, rather than in the late Cenozoic, as has been previously suggested.

The ophthalmosaurid Caypullisaurus from the Late Jurassic–Early Cretaceous of the Neuquén Basin, Argentina, is redescribed based on new information from recent discoveries. Cladistic analysis of Caypullisaurus, based on previous ichthyopterygian data sets and using NONA, yielded two most parsimonious trees. Two clades are recognized within the Ophthalmosauridae. Caypullisaurus is found to be nested with Brachypterygius and Platypterygius. Simultaneous, unconstrained analysis, using unambiguous character optimization, is suggested as the best way to analyze data sets with large amounts of missing data.

Five new bivalved arthropods are described from the Lower Cambrian Chengjiang fauna, Yunnan, China. All of them are rare in the fauna, represented by one or two individuals among thousands of specimens. Four of the five new taxa are preserved with soft parts that show a clear distinction between them. The new taxa provide new important information concerning the soft bodied and limb characters of the early bivalved arthropods. A significant lesson is that, not knowing any soft parts, it is virtually impossible to place systematically a new type of bivalved carapace. It is often impossible even to tell if it is a crustacean or not. A second antenna in the shape of a “great appendage” is identified for the first time among the bivalved arthropods. The new taxa include representatives of the order Pectocaridida, the families Pectocarididae, Clypecarididae and Occacarididae, the genera and species Pectocaris spatiosa, Clypecaris pteroidea, Occacaris oviformis, Forfexicaris valida and Yunnanocaris megista.

The large number of ichnospecies in Permian vertebrate ichnology literature is often a result of a failure to recognize substrate or gait-controlled variations in trackway morphology. Additionally, regional studies were often performed in isolation from studies in other areas. Nomenclatural priority applies to the names first assigned to trackways from the Corncockle and Locharbriggs Sandstone Formations (Permian) of Dumfries and Galloway, Scotland. Only one ichnogenus, Chelichnus, and four ichnospecies are recognized here and all had been identified in the studies of Jardine in 1850 and 1853. Chelichnus represents tetrapod trackways with rounded manus and pes impressions, subequal in size with up to 5 short digits where preservation is complete. The normal trackway pattern shows a pes pace angulation of up to 90° with the manus and pes being impressed close together or possibly with a slight overlap of the manus by the pes. Chelichnus bucklandi shows a pes size of 10 to 25 mm, C. duncani shows a pes size of 25 to 75 mm, C. gigas shows a pes size of 75 to 125 mm, and C. titan displays a pes size exceeding 125 mm in length. This restriction to four ichnospecies is more in accord with the low faunal diversity to be expected from an eolian environment of Late Permian age than was the former taxonomic classification. The Permian ichnofaunas of the Coconino Sandstone of Arizona and the Cornberger Sandstein of Germany are also composed largely of these four ichnospecies.

Scrippsiella trifida Lewis, 1991 ex Head, 1996 is a nontoxic marine calciodinelloidean dinoflagellate whose resting cyst has a distinctive wall containing large, erect, trifurcate, recurving calcareous processes that separate two organic layers. We show that the organic wall layers of living Scrippsiella trifida cysts are resistant to acetolysis and can therefore potentially fossilize, and we report on abundant Scrippsiella trifida cysts from latest Pleistocene and early Holocene marine sediments off eastern Canada, representing the first confirmed fossil discovery of this species in the North Atlantic. A reappraisal of late Quaternary palynological records now shows that the organic remains of Scrippsiella trifida cysts have been widely misidentified as cysts of Alexandrium tamarense (Lebour, 1925) Balech, 1985, a goniodomacean (and hence noncalcareous) dinoflagellate and major cause of paralytic shellfish poisoning in humans. The morphology of these two cyst types is contrasted, and the modern and fossil distribution of Scrippsiella trifida cysts in sediments of the North Atlantic and adjacent areas is now clarified. It is apparent from this distribution that Scrippsiella trifida favors neritic environments characterized by cool winters and relatively warm (14°–25°C) summers. Extremely high fluxes of S. trifida cysts in nearshore areas off Nova Scotia and southern Greenland during deglaciation and early postglacial time (14–7 ka) have no modern analog but may signal a reduction in salinity caused by meltwater discharge. In general, the organic walls of calcareous dinoflagellate cysts are more common components of palynological assemblages than hitherto realized.

Morphometric analyses of silicified and nonsilicified (preserved in shale) specimens of the olenelloid trilobites Olenellus (Olenellus) gilberti Meek (in White, 1874) and Nephrolenellus geniculatus Palmer, 1998, from the Lower Cambrian C-Shale Member of the Pioche Formation show that even well-preserved specimens in shales have undergone significant changes in lateral as well as vertical dimensions as a result of compaction. Analyses of cephalic landmarks show that in both species compaction causes posteriordirected collapse of the anterior lobe of the glabella, adaxial deformation of the ocular lobes, and abaxial and anterior splaying of genal regions. These shape changes are explicable in terms of observed exoskeletal fracture patterns. Landmarks show an increase in scatter around their ontogenetic trajectories that is generally proportional to the degree of lateral shift each landmark has undergone. Interspecific differences in compactional response may depend on the relative convexity of the cephalon. Olenellus (Olenellus) gilberti is a low-convexity species and shows marked lateral shape change, particularly in the genal region. Nephrolenellus geniculatus is more convex and shows less severe lateral shape change. Landmarks of both species exhibit an average trebling of the degree of scatter around their average ontogenetic trajectories in compacted samples. Because even well-preserved specimens in shales differ in shape from their precompactional appearance, results of morphometric studies utilizing metric distances between landmarks in trilobites where compaction can be detected must be interpreted with caution.

The most important factor controlling the timing of Phanerozoic mineralogical evolution in the Bivalvia appears to be thermal potentiation of calcite deposition in colder marine and estuarine environments. Cold temperature has promoted mineralogical evolution in the Bivalvia by kinetically facilitating (potentiating) initially weak biological controls for calcite, thereby exposing their genetic basis to natural selection. Calcite has evolved in bivalve shells for a variety of selective advantages, including resistance to dissolution; resistance to chemical boring by algae and gastropods; reduced shell density in swimming and soft-bottom reclining species; enhanced flexibility in simple prismatic shell layers; and fracture localization and economy of secretion in association with certain foliated structures.

Endogenous calcite in bivalve shells varies from biologically induced to weakly and strongly biologically controlled. Biologically controlled calcite generally first appears in bivalve shells as an impersistent component of the outer shell layer, only later, in some groups, expanding to include the entire outer and then part or all of the middle and inner shell layers. The initial stages of mineralogical evolution are shown by certain modern Mytilidae, Veneridae and Petricolidae. In the latter two families, the calcite occurs as conellae in the outer part of the outer shell layer. Calcitic conellae in the inner shell layer of Pliocene Mercenaria are not barnacle plates, as previously indicated, but endogenous calcite comparable in origin to other venerid conellae. Their occurrence in Mercenaria may reflect thermal potentiation of weak biological controls for calcite, as well as local detachment of the secretory mantle epithelium near the pallial and adductor musculature.

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.

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.

Fossilized leaf mines and other traces of phytophagous insects provide a unique window into ecological and evolutionary associations of the past. Leaf-mining flies (Diptera: Agromyzidae) are an important component of the recent leaf-mining fauna, but their fossil record is sparse compared to other mining insect lineages; many putative agromyzid body fossils and traces are dubiously assigned. Agromyzid leaf mines often can be distinguished from those of other insects by the presence of an intermittent, fluidized frass trail that may alternate between the sides of the mine. Here, we describe two new Paleogene leaf mine fossils, Phytomyzites biliapchaensis Winkler, Labandeira and Wilf n. sp. from the early Paleocene of southeastern Montana, USA, occurring in leaves of Platanus raynoldsii (Platanaceae); and Phytomyzites schaarschmidti Wappler n. sp., from the middle Eocene of Messel, Germany, occurring in leaves of Toddalia ovata (Rutaceae). These fossils both exhibit frass trails indicative of an agromyzid origin, and P. biliapchaensis also exhibits associated stereotypical marks identical to damage caused by feeding punctures of extant adult female Agromyzidae prior to oviposition. Phytomyzites biliapchaensis represents the earliest confirmed record of Agromyzidae, and one of the earliest records for the large dipteran clade Schizophora. Plant hosts of both species belong to genera that are no longer hosts of leaf-mining Agromyzidae, suggesting a complex and dynamic history of early host-plant associations and, for the early Paleocene example, an evolutionary, possibly opportunistic colonization in the midst of the ecological chaos following the end-Cretaceous event in North America.