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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.
Late Givetian and early Frasnian conodont communities with Icriodus subterminus have been revised on the basis of collections from Iowa (USA), the Boulonnais and the Ardennes (northern France and Belgium), the Radom-Lublin area and Holy Cross Mountains (Poland), and the Ma'der-Tafilalt region (southeast Morocco). As a result an Icriodus subterminus Zone with a threefold subdivision is defined. The three subzones correspond approximately to the “Lower and Upper subterminus Fauna” and the “insita Fauna” commonly used in N America for the study of shallow-water platform carbonate successions.
The base of the subterminus Zone corresponds to a level within the uppermost part of the hermanni Zone; the top is characterized by the occurrence of the earliest Ancyrodella taxa, Montagne Noire Zones MN 1 and the base of MN 2 or slightly above the base of the falsiovalis Zone.
The diagnosis of Icriodus subterminus is amended and two morphotypes are recognized. The stratigraphic range of the alpha morphotype is confined to an interval between the uppermost part of the hermanni Zone and the top of the MN 3 Zone; the beta morphotype may range into the MN 6 Zone.
The holotype of Icriodus subterminus from the North Liberty beds in Iowa is most likely a specimen that was reworked from the Cedar Valley Limestone. Icriodus cedarensis and Icriodus tafilaltensis are described as new species, and the diagnoses of Icriodus excavatus and Icriodus expansus are amended. Between the Icriodus difficilis and Icriodus symmetricus zones, an Icriodus expansus Zone is defined.
The camerates, Pycnocrinus argutus (Walcott, 1883) and Rhaphanocrinus subnodosus (Walcott, 1883), are characterized by narrow food grooves. An open distal stem coil was present in P. argutus, and R. subnodosus may have possessed the same type of holdfast. Such holdfasts either lay loose on the seafloor or were wrapped around unknown soft objects. The rhaphanocrinids were located at elevations of at least 300 mm above the substrate. Conversely, the much smaller pycnocrinids lived close to the seafloor at levels of about 10 to 24 mm. The three cladids are Merocrinus curtus (Ulrich, 1879), M. retractilis (Walcott, 1883), and Dendrocrinus gregariusBillings, 1857a. Merocrinus typusWalcott, 1883 and M. corroboratusWalcott, 1883 are conspecific with M. curtus. The spiral anal sac of M. retractilis is unique. Embryocrinus problematicusHudson, 1918 probably represents a juvenile of Dendrocrinus gregarius, which also occurs in Ottawa, Ontario. Complete columns and attachment structures have not been found for D. gregarius and Merocrinus retractilis. Merocrinus curtus ranges from New York into the Cincinnati, Ohio area of the midcontinent. Although attachment devices and long stem segments are not preserved in the New York specimens, individuals of Merocrinus curtus from Cincinnati either have a conical holdfast cemented to a bryozoan or a tight distal stem coil that was wrapped around the stem of another crinoid; adult merocrinids from the Cincinnati region were positioned high above the seafloor, and incomplete stem segments up to about 800 mm long are known. The Walcott-Rust Quarry cladids all possessed wider food grooves than the camerates, so they were able to catch larger food particles.
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.
A new genus and species of edrioasteroid grade echinoderm, Kailidiscus chinensis, is described from the Kaili Biota of the basal lower Middle Cambrian Kaili Formation from Guizhou Province, China. This echinoderm has a strong resemblance to isorophid edrioasteroids, bearing a well-developed peripheral rim, long curved ambulacra, and slightly imbricate interambulacral plating at maturity. However, the presence of pore-bearing, double biserial floor plates, tiered cover plates, lack of radially positioned oral frame plates, and unincorporated hydropore/gonopore are unknown in isorophids. Many of these features bear strong resemblance to eocrinoids and helicoplacoids, attesting to the plesiomorphic nature of this taxon. Despite the obvious anatomical differences, specimens of this species preserve a complete ontogeny that resembles that of isorophids. Juveniles show a discoidal theca with straight ambulacra that transitions to an inflated theca with strongly curved ambulacra with maturity.
A new genus of long-horned chasmosaurine ceratopsid is described from the Dinosaur Park Formation (upper Campanian) of Western Canada. Mojoceratops perifania is represented by a skull and a parietal from the Dinosaur Park Formation of Alberta and an isolated parietal from the Dinosaur Park Formation of Saskatchewan. Several other specimens are provisionally referred to this taxon. While Mojoceratops shares many plesiomorphies with Chasmosaurus, the animal lacks the forward-curving parietal epoccipitals and reduced postorbital horns that diagnose the genus Chasmosaurus, and it differs from all other chasmosaurines in exhibiting a prominent sulcus on the anterior margin of the parietal, swellings on the anterodorsal surface of the parietal rami, and a small accessory process on the first parietal epoccipital. Other unusual features include anteriorly extended parietal fenestrae, a broad, heart-shaped frill, and transverse expansion of the postfrontal fontanelle. The type material of “Eoceratops canadensis” and “Chasmosaurus kaiseni” are nondiagnostic and these names are therefore considered nomina dubia, but their morphology is consistent with Mojoceratops and they probably belong to this genus. The frill of Mojoceratops shows marked variation. Some of this variation probably results from intraspecific variation or ontogenetic changes, but because the Dinosaur Park Formation encompasses more than a million years of time, evolution may explain some of these differences. Phylogenetic analysis shows that Mojoceratops forms a clade with Agujaceratops mariscalensis; Chasmosaurus is the most basal member of Chasmosaurinae.
The new genus Iberostomata (Bryozoa, Ptilodictyina) from the Cystoid Limestone Formation in the Iberian Chains (NE Spain) is here described and its phylogenetic relationships analyzed using cladistic methods. Twenty-eight identifying characters used in traditional systematics have been codified for nine ptilodictyine families, two timanodictyine families and 34 ptilodictyine genera. The results obtained in this analysis place the new genus Iberostomata and the genus Stellatodictya, traditionally included in the family Ptilodictyidae, in the family Rhinidictyidae, question the validity of the family Intraporidae, question the assignment of Amurodictya and Astrovidictya to the family Stictoporellidae, as well as the assignment of the genera Junggarotrypa, Goniotrypa, and Prophyllodictya to the family Rhinidictyidae, and place the family Phragmopheridae in a uncertain systematic position.
Cythere ikeyanoriyukii n. sp., an extant phytal ostracode genus, was obtained from the Middle Eocene McIntosh Formation in the Doty Hills, western Washington State, USA. It was associated with eleven taxa, which are extant phytal and shelfal genera such as Loxocorniculum, Xestoleberis, Ambostracon, Coquimba, and Acanthocythereis. The presence of Cythere in this assemblage is surprising and indicates that the first appearance of this genus was middle Eocene time at the latest, or at least 20 Ma earlier than previously thought. Cythere did not originate in the Pacific Ocean around Japan as previously thought, but instead must have migrated from the northeastern Pacific to the northwestern Pacific between middle Eocene and early Miocene time.
Studies of paleoenvironments have commonly focused on large mammalian herbivores such as ungulates. Many localities, however, have yielded large numbers of small mammalian herbivores, including lagomorphs and rodents. These fossils represent an untapped paleoecological resource. However, the fossils are often in the form of isolated teeth, and microwear analysis cannot be used due to taphonomic alteration. As a result, we use ungulate gross dental wear as a model. The dental wear features of extant western Canadian lagomorphs are identified and used to create dietary categories that can be applied to make predictions about the diets of extinct forms. The Horse Local Fauna of the Cypress Hills Formation of Saskatchewan has yielded approximately 2,500 fossil specimens, of which nearly 300 are lagomorphs. Two leporid species (rabbits and hares) are present in the Horse Local Fauna, Palaeolagus temnodon and Megalagus brachyodon. Qualitative analysis of the gross dental wear of the lagomorphs of the Horse Local Fauna indicates that M. brachyodon was mainly folivorous and P. temnodon was primarily frugivorous, suggesting that the contemporaneous ecosystem was tree dominated. Gross dental wear analysis allows the use of small herbivores and isolated teeth in paleoecological studies. Studying the diets of small herbivorous mammals will allow more nearly complete reconstructions of past environments and will become increasingly important as more detailed reconstructions are required by paleontologists.
Lower Miocene tide-influenced deltaic deposits from the Chenque Formation, Patagonia, Argentina, contain abundant and well-preserved biogenic structures attributed to locomotion of deposit-feeder protobranch bivalves. These trace fossils, assigned to the ichnogenus Protovirgularia, consist of delicate, inclined-to-horizontal, chevronate structures, mostly symmetrical with respect to a median axis. Identification of Protovirgularia at sandstone sole beds (hypichnion) is quite straightforward. Endichnial, exichnial and epichnial preservation in heterolithic facies, however, provides a wide variety of forms that depart from the archetypal Protovirgularia and challenges ichnotaxonomic classification. Specimens in prodelta and delta-front facies display morphologic features controlled by substrate fluidity, toponomy, and sedimentation rate. Most specimens show sharp, closely spaced chevrons and occur along sandstone/mudstone interfaces of the proximal prodelta and distal delta-front deposits. These forms reflect how tracemakers experienced significant friction while advancing through the sediment, which resulted in relatively smaller increments of movements. In contrast, variants of Protovirgularia formed in muddier beds, such as in prodeltaic facies, show irregular, poorly defined and unevenly spaced chevrons, and are locally asymmetric in relation to the axis, reflecting softer, water-rich, and plastic substrates. This sediment offered relatively low friction but poor anchorage for the foot. These occurrences of Protovirgularia in tide-influenced, marginal-marine deposits suggests that protobranchs were tolerant of fluctuations in salinity, sedimentation rates, turbidity, and oxygen depletion, displaying opportunistic strategies in stressed nearshore environments. Our evaluation of taphonomic controls and appropriate identification of Protovirgularia can provide valuable information for expanding our knowledge of the ethology and paleoecology of protobranch bivalves.
Among hyoliths from the Givetian Kersadiou Formation in northwestern France one form is assigned to Hyolithes triliratusHall, 1879, which is used as the basis for Brittanella new genus. The occurrence of this species in France supports affinity for fauna in that region to the Eastern Americas Realm. Other hyoliths from this unit include one species of Hyolithes Eichwald, which is left in open nomenclature, and one conch and one platyclaviculate operculum that cannot be identified to genus. The occurrence of these fossils in concretions in an oxygen-stressed dark gray shale supports the notion that this environment served as a refuge for taxa that were less efficient competitors with other normal marine benthos in the Devonian.
Representatives of the family Strephocladidae have been considered as fossil relatives (i.e., stem-group) of Mantodea (mantises) based on characters of the forewing morphology. Here we describe new specimens from the Wellington Formation that we assign to the strephocladid species Homocladus grandisCarpenter, 1966. The range of morphological variation exhibited by the new material, in addition to wing morphology variability documented in extant mantises and roaches, suggest that H. ornatusCarpenter, 1966 and Paracladus retardatusCarpenter, 1966, reported from the same formation, are new junior subjective synonyms of H. grandis. We describe the first hind wing for this species based on a well-preserved specimen. It exhibits a combination of character states unique to dictyopteran insects.
An assemblage of seventeen species of Small Shelly Fossils, dominated by the brachiopod Eothele tubulus and species of the mollusk Yochelcionella, is described from the basal Kinzers Formation of Thomasville, Pennsylvania. The occurrence extends southwards the distribution of an Early Cambrian fauna (Cambrian Series 2, Stage 4) that is otherwise characteristic of the eastern shelf of Laurentia from New York to Greenland. The poorly known acrothelid brachiopod Eothele tubulus is redescribed based on large collections of ventral valves. The shell structure of E. tubulus is characterized by orthogonal baculae, and represents the oldest known example of a baculate shell structure, indicating that this type of shell structure evolved already in the Early Cambrian.
An Anchitherium specimen with a nearly complete series of the upper cheek teeth (P2–M3), from the upper part (ca.17–18 Ma) of the Hiramaki Formation, Kani Basin, Gifu Prefecture, Japan, was previously referred to Anchitherium “hypohippoides” nomen dubium. Despite that it provides one of the best examples of significant dental characters of Asian Anchitherium, it has remained undescribed and unprepared until recently. Although a paucity of materials from Asia makes the taxonomy of Asian Anchitherium difficult to assign, comparison showed that the specimen should be reassigned to Anchitherium aff. A. gobiense; it differs from A. aurelianense and is rather similar to A. gobiense from China by virtue of large size and expanded hypostyles. The Japanese Anchitherium also shows distinct features including straight (flattened) ectolophs with narrow mesostyles, rudimentary crochets, and enamel protuberances at the lingual mouth of the median valleys. This combination of accessory features has not been known in Asian Anchitherium and seems to be rarely observed among the diversified European species. The existence of Japanese Anchitherium implies early species diversification in East Asia that predates a greater diversification in Europe associated with the Middle Miocene Climatic Optimum and supports paleogeographical and paleozoological connection to the Asian mainland under a warm and humid climate prior to the formation of the Japanese archipelago (ca. 16.5 Ma).
Megaloptera is a small order of insects that is very rare in the fossil record. Jurochauliodes ponomarenkoi n. gen. n. sp. belonging to Chauliodinae (fishflies) within Corydalidae is described based on three larvae preserved in tuffaceous siltstones from the Middle Jurassic of Daohugou, China. It is not only the first fossil Megaloptera from China, but also the earliest Corydalidae. It differs from Cretochaulus lacustrisPonomarenko, 1976 in having a large body, head much longer than mandibles, mandibles wide, with a small apical tooth, meso- and metathorax half as long as prothorax, profemora apically widened, abdominal segment IX short, and lateral gills shorter than hind legs. This discovery indicates that fishflies originated at least in the Middle Jurassic.
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