Ordovician material from the Platteville Formation (Sandbian) of southern Wisconsin and Big Hill Formation (Katian) of northern Michigan is described that provides novel information about the phylogenetic affinity, taxonomic diversity, and stratigraphic range of the nonbiomineralized taxa Buthograptus, Callithamnopsis, and Chaetocladus. Two new species of Buthograptus, a previously monotypic genus, are erected on the basis of the Platteville Formation material, Buthograptus gundersoni n. sp. and B. meyeri n. sp., and new occurrences of B. laxus are recorded from several localities and two distinct stratigraphic levels within this unit. On the basis of scanning electron microscopic investigation of the material and the fact that each of the three Buthograptus species has a close counterpart in the frond morphology of an extant species of Caulerpa, Buthograptus is interpreted as a member of the green algal order Bryopsidales. New specimens from the Platteville Formation assigned to Callithamnopsis reveal new morphological details for the type species, C. fruticosa (Hall, 1865), aspects of which indicate that the genus belongs to the family Triploporellaceae rather than Seletonellaceae within the green algal order Dasycladales, and Chaetocladus material from the Big Hill Formation includes specimens that are formally assigned to Chaetocladus dubius (Spencer, 1884), a species of dasycladalean alga known previously only from the mid-Silurian of Ontario.

Hippuritids, particularly those with multiple-folds, are one of the most characteristic components in uppermost Cretaceous rudist-bearing strata of the Caribbean Province. The hippuritid rudist fauna of the Chiapas Central Depression includes the following taxa: Vaccinites vermunti Mac Gillavry, 1937 and Barrettia cf. B. ruseae Chubb, 1967 from the early Campanian Suchiapa Formation; B. monilifera Woodward, 1862, B. gigas Chubb, 1955, and Parastroma trechmanni Chubb, 1967 from the mid Campanian Suchiapa Formation; and Praebarrettia sparcilirata (Whitfield, 1897) from the early Maastrichtian Ocozocoautla Formation. These six species are described herein in detail. New observations on the outer shell layer structure of the right valve and the pore-canal system of the left valve led to amending the diagnoses of the g|enera Barrettia Woodward, 1862, Parastroma Douvillé, 1926, and Praebarrettia Trechmann, 1924. Also, the revision of Chiapas’ and other American species of multiple-fold hippuritids led to proposed changes in their generic adscription.

In the El Castro Formation, cropping out on the Asturian coast of northern Spain, two fossiliferous horizons have been studied. Above the basal one, containing the Llandeilian brachiopods Tissintia cf. T. convergens and Howellites? sp., a new horizon of estimated Ashgillian age has been identified that has yielded the new brachiopod species Mcewanella vulcanica and Hesperinia asturica. The new species of Mcewanella, close to the Irish Rawtheyan Mcewanella dorsisulcata, is characterized by a great delay of the insertion of costellae, which gives many adults a strikingly costate ornament for this genus. Hesperinia was, up to now, poorly known from a small number of specimens from the Llanvirnian Tank Hill Formation in Nevada; thus, the new record, besides allowing a better understanding of the genus and its relationship with other oepikinids, extends its known time span to the Late Ordovician. These two species were dwellers on a low-energy bottom formed of loose sand and gravel supplied by nearby volcanic eruptions. The ash-flow depositional pattern of these sediments would have had lethal effects on the brachiopod communities, periodically causing their destruction. These species of the genera Mcewanella and Hesperinia are new representatives of the immigration of North American and Northern European warm-water faunas into the circumpolar Mediterranean Province during the Late Ordovician.

“Phylloid algae” (Pray and Wray, 1963, p. 209) are problematical fossils that occur profusely in Pennsylvanian carbonate microfacies in the United States (Wray, 1968) and many other parts of the world (Mamet, 1991). Taxonomic affinities of most phylloid alga are uncertain. The questionable affinities of phylloid algae and related paleoecologic problems have been summarized by Riding (1977), Wray (1979), and James et al. (1988) and will not, therefore, be repeated here. Our ability to establish probable taxonomic affinities of fossil calcareous algae is dependent largely upon the recognition of their internal microstructures. Because phylloid algae are very susceptible to dissolution and neomorphism, their original internal microstructures are rarely well preserved.

Ptyctodonts from the Upper Devonian Martin Formation on Mt. Elden, northern Arizona, were hitherto known only from tooth plates ascribed to Ptyctodus bradyi. Recent collections include dental elements of P. bradyi as well as body and skull plates and dental elements of a previously unknown ptyctodont, described here as Denisonodus plutonensis new genus and species. Comparison with other ptyctodonts suggests that the new genus has close affinities to other North American forms. As the holotype of Ptyctodus bradyi has been lost a neotype is designated here.

Although the order Odonata has a rich fossil record, many questions about its reproductive biology remain unanswered. There are two strategies of egg laying among odonates, exophytic and endophytic, the latter being one of the most revealing vestiges of plant–insect association in the fossil record. We assessed whether geometric morphometrics based on elliptical series of Fourier allow expression of variability of shape in traces of Odonata eggs within a leaf of Eucalyptus chubutensis (Berry) González (in part), González, 2009 (Myrtaceae) from Laguna del Hunco (Chubut, Argentina) (early Eocene) and whether this variability is consistent with the ichnotaxonomy of this material. We found that the largest variation corresponds to the compression of the shape while the remaining two components reflect variations in the apex position and its curvature, which changed according to the relative position of the traces in the leaf. There was no evidence that the hardness of the leaf would affect the shape of the egg trace. We postulate that these traces could have been produced by one single female: Variations in the pattern observable in the fossil of an originally three-dimensional structure are consistent with differences in the position of the eggs inserted by a single female who has flexed her abdomen to insert the eggs as she approaches the apex of the leaf (behavior observed also in extant dragonflies). For the first time, endophytic egg traces are analyzed with geometrical morphometrics, and this allows us to make inferences on the oviposition behavior of a female that lived around 52 million years ago.

A megafossil flora, composed of 12 form taxa, has been collected from the Upper Mississippian–Lower Pennsylvanian Surprise Canyon Formation in the Grand Canyon, Arizona. It is the first known flora of this age to be recorded in Arizona, and includes Lepidodendron aculeatum Sternberg, L. mannabachense Presl, L. volkmannianum Sternberg, Lepidostrobus sp. cf. L. ornatus Brongniart, Lepidostrobophyllum sp., Knorria sp., Cyperites sp., Stigmaria ficoides (Sternberg), Calamites (Mesocalamites) cistiiformis Stur, Calamites sp., Pecopteris cf. P. aspera, and Wardia sp. (seed). The 22 species of palynomorphs previously reported from this formation suggest that the local flora was more diverse than the paucity of plant megafossil specimens indicates.

Six extant and nine fossil species of the raninid Lyreidus de Haan, including Lyreidus (Lyreidus) lebuensis n. sp. and Lyreidus (Lysirude) hookeri n. sp., are recognized. Based on morphology of the anterolateral margin and sternum, the species are referred to two subgenera, Lyreidus (Lyreidus) and Lyreidus (Lysirude). The genus first appears in shallow-water, high-latitude, southern hemisphere localities in New Zealand, Antarctica, and Chile in the early Eocene. Subsequently, the nominate subgenus is confined to the southern hemisphere until the Neogene when it dispersed into the Indo-West Pacific region. Lyreidus (Lysirude) is documented by early and middle Eocene occurrences in Antarctica and New Zealand; however, all subsequent occurrences, fossil and recent, are in the northern hemisphere. The disjunct modern distribution within the genus is confined to this subfamily; species are known from the western North Atlantic and the Indo-West Pacific.

Species of Eugonophyllum (Codiaceae, Chlorophyta) have traditionally been characterized as phylloid or leaf-like. But a reconstruction of well preserved specimens of Eugonophyllum, probably E. johnsonii Konishi and Wray, from Upper Pennsylvanian limestone formations of Palo Pinto County, Texas, indicates it was cyathiform or cup-shaped. Reconstruction was based on the forms of membranes as seen in sections and on partial excavation of thalli. This Eugonophyllum shared with congeneric species of Eugonophyllum the characteristic two-layered cortex (outer and inner), and with other codiaceans the same general membrane structure consisting of bilateral cortices with palisades of utricles now filled with micrite, and a medulla of tubular coenocytes, an area now mostly filled with mosaic sparry calcite. A cyathiform thallus would have inner and outer cortices but no differences were found in the structure of the inner and outer cortical utricular casts. The thalli were apparently anchored with elongated, cylindrical holdfasts. Internal spherical structures, presumably developed from differentiated utricles, may have been zygotes or young embryos from an oogamous fertilization. These were apparently released to the environment through the membrane.

During growth of colonial corals, the basic organization of skeletal elements was determined by inherent factors, but arrangement of corallites within a colony could be affected if environmental change induced a modified growth form. Comparisons of internal and external characters during colony development indicate how environmental and genetic factors determined growth form. The results of these comparisons have implications for understanding of colony integration, functional morphology, and systematics.

This study is based on serially sectioned coralla of the cerioid tabulate Paleofavosites subelongus, from the uppermost Ordovician to lowermost Silurian of the east-central United States. Colony growth form resulted from changes in maximum growth angle of marginal corallites, and in the shape of the growth surface. These features were coordinated with corallite characters and were dependent on variation in corallite growth. At the same time that a colony became broader by expanding its maximum growth angle and developing a taller growth surface, its corallites became larger, more new corallites were initiated, and recently initiated corallites expanded more rapidly. When a colony's maximum growth angle was reduced and the growth surface became flatter, corallites also became smaller, fewer corallites were initiated, and those corallites that were recently initiated expanded slowly.

Genetic constraint of growth is illustrated by consistent patterns of initial colony growth, and by relationships among characters of internal and external morphology. Frequent small-scale variations in growth angle and growth surface height:width during astogeny indicate fluctuating environmental factors. Sedimentation and subsidence of the colony were probably the major environmental controls on form.

The late Paleozoic temnospondyl Sclerocephalus formed an aquatic top predator in various central European lakes of the late Carboniferous and early Permian. Despite hundreds of specimens spanning a wide range of sizes, knowledge of the endocranium (braincase and palatoquadrate) remained very insufficient in Sclerocephalus and other stereospondylomorphs because even large skulls had unossified endocrania. A new specimen from a stratigraphically ancient deposit at St. Wendel in southwestern Germany is recognized as representing a new taxon, S. concordiae new species, and reveals a completely ossified endocranium. The sphenethmoid was completely ossified from the basisphenoid to the anterior ethmoid region, co-ossified with the parasphenoid, and the basipterygoid joint was fully established. The pterygoid bears a slender, S-shaped epipterygoid, which formed a robust pillar lateral to the braincase. The massive stapes was firmly sutured to the parasphenoid. In the temnospondyl endocranium, character evolution involved various changes in the epipterygoid region, which evolved distinct morphologies in each of the major clades.

UUID: http://zoobank.org/5e6d2078-eacf-4467-84cf-a12efcae7c0b

Laocoetis piserai n. sp. (Hexactinellida, Porifera) from the mid-Cretaceous (i.e., Albian–Cenomanian) of James Ross Island is the first record of a fossil sponge from Antarctica. This new occurrence of a formerly widespread genus was restricted to relatively deep waters on the margins of an active volcanic arc. Its occurrence in Antarctica is further evidence that the genus Laocoetis underwent a dramatic reduction in its geographic range through the Cenozoic. The only living species of the genus at the present day is Laocoetis perion from Madagascar.

Additional Silurian (Ludlovian) gastropods are described from the Heceta Formation in the Alexander terrane on Prince of Wales Island, southeastern Alaska. Species include Spinicharybdis krizi n. sp., Spinicharybdis boucoti n. sp., Morania wagneri n. sp., Haplospira craigi n. sp., Australonema sp., Pachystrophia cf. gotlandica (Lindström, 1884), and Medfrazyga gilmulli n. sp. An additional new Silurian species, Morania nixonforkensis n. sp., is described from the Nixon Fork subterrane of the Farewell terrane of west-central Alaska.

The spine-bearing Spinicharybdis is placed into a new subfamily Spinicharybdiinae together with Hystricoceras Jahn, 1894. Joint occurrences of genera Beraunia, Coelocaulus, and Morania, as well as members of subfamily Spinicharybdiinae in the gastropod fauna from the Heceta Formation, support its close relationship with gastropod fauna of Bohemia. Additionally, the occurrence of the genus Medfrazyga suggests a faunal link between the Alexander and Farewell terranes of Alaska. Medfrazyga gilmulli n. sp. is the oldest known and the only early Paleozoic member of the family Palaeozygopleuridae.

Phragmactis grayae Spencer and Swataria derstleri new genus new species are early (Ordovician) asterozoans (Echinodermata) that comprise the Phragmactinidae. Asterozoans are complexly varied, but as is true for other echinoderms, ambulacral construction is critical to interpretation. Phragmactinids share plesiomorphic aspects of ambulacral form and articulation with basal somasteroids and stenuroids whereas the apomorphic ambulacral expressions of asteroids and ophiuroids are lacking. Phragmactinids, like asteroids and ophiuroids, have only one virgal-series ossicle associated with each ambulacral, unlike the multiple ossicles of somasteroids and stenuroids. Virgal morphology of phragmactinids is reminiscent of expressions in somasteroids and stenuroids. Aspects of phragmactinid mouth frame construction are apomorphic. Morphologies of other ossicular series are similarly varied, and as a result, the family cannot be easily fitted into a recently proposed class-level taxonomy of early asterozoans; it is left in open nomenclature. Phragmactinid morphology does not indicate behavior significantly different from that of other early asterozaons. Asterozoan diversity suggests an early period of rapid evolutionary radiation.

The taxonomy and phylogenetic position of the hadrosaurid dinosaur Barsboldia sicinskii is revised. This species is rediagnosed based on the unique combination of iliac central plate with depth/length ratio less than 0.8 and sacral vertebrae with distally ‘clubbed’ neural spines at least four times higher than their centra. A maximum parsimony analysis of 47 hadrosauroid (39 hadrosaurid) species does not support the purported lambeosaurine affinities of B. sicinskii, but recovers this form as a basal saurolophine hadrosaurid based on unambiguous synapomorphies of the ilium. This result increases the diversity of saurolophine taxa in Asia, a continent with a hadrosaurid fossil record so far dominated by lambeosaurines. Finally, several vertebral and iliac characters previously regarded as diagnostic of Lambeosaurinae are discussed and shown to be uninformative from a taxonomic or phylogenetic standpoint.

Specimens of the large, shallow-marine, volutid gastropod Volutoderma Gabb, 1877, herein recognized only from strata of Late Cretaceous (Coniacian through early Maastrichtian) age in British Columbia, Washington, California, and Baja California have commonly been identified as Volutoderma averillii (Gabb, 1864). This review of available specimens assigns them to two genera: Volutoderma and Longoconcha Stephenson, 1941.

Twelve species, nine of them new, comprise three morphologic lineages of Volutoderma, i.e., 1) “Typical” includes V. querna n. sp., V. averillii (Gabb), V. blakei n. sp., V. jalama n. sp., V. perissa n. sp., and possibly Volutoderma? n. sp.; 2) “Angelica” includes V. angelica n. sp., V. elderi n. sp., and V. ynezae n. sp.; and 3) “Magna” includes V. santana Packard, V. magna Packard, and perhaps V.? antherena n. sp. A new species of Longoconcha, L. eumeka, is the first Pacific Slope record of this genus, which has a Gulf Coast and Tethyan Old World distribution. A smaller volutid, Retipirula Dall, 1907 is endemic to the study area and was formerly known only from its type species R. crassitesta (Gabb, 1869) of Paleocene age. Two new Retipirula are reported: R. calidula of latest Maastrichtian age and R. pinguis of Paleocene age.

Only the Volutoderma lineage containing V. averillii has been found north of San Francisco. Recovery of rudist bivalves from formations yielding Volutoderma suggests that these volutes were warm-temperate to subtropical gastropods. Co-occurrences of these gastropods and rudistids may aid in placing the warm-temperate/subtropical boundary during the Late Cretaceous.

How will freshwater lakes in the Arctic respond to climate change, especially if polar amplification results in even greater warming at these northern latitudes? Deep time analogs offer opportunities to understand the potential effects of future climate warming on arctic environments. A core from the Giraffe Pipe fossil locality located in the Northwest Territories of Canada offers a window into the life of a thriving Arctic freshwater ecosystem in the Eocene during greenhouse conditions. The remains of an extensive deposit of microfossils, including photosynthetic protists (chrysophytes, diatoms, and green algae), heterotrophic protists (euglyphids, heliozoans, paraphysomonads, and rotosphaerids), and sponges, were used to reconstruct the history of the ancient waterbody. Concentrations and diversity of chrysophyte taxa were extensive throughout the core, accounting for >70% of the microfossil remains. The ratio of chrysophyte cysts to diatom valves, with a mean value near 14 throughout the core, further emphasized the dominance of the chrysophytes, and given the high diversity of taxa, the locality represents a “paleo-hotspot” for this eukaryote lineage. Based on the totality of fossil evidence, the waterbody within the Giraffe Pipe crater represented a series of relatively shallow aquatic habitats, with changing physical and chemical conditions, and varying water depths. Five major zones were identified, each found to be stable for an extended period of time, but with distinct transitions between successive zones signaling significant shifts in environmental conditions. The study provides valuable insight on how Arctic freshwater ecosystems responded to past warm climates, and to the organisms that could potentially thrive in these environments under future warming scenarios.

The Ao Mo Lae Formation of the Tarutao Group crops out on Thailand's Tarutao Island and contains a diverse assemblage of late Furongian trilobite taxa, including several endemic forms. This study presents a new genus and species, Satunarcus molaensis, discovered at two locations on the island. A cladistic analysis of the kaolishaniid subfamily Mansuyiinae in light of Satunarcus and similar genera known from across upper Cambrian equatorial Gondwanan rocks suggests that the subfamily is polyphyletic in its current definition, and thus is not a natural group. Separating Mansuyia Sun, 1924 from the other taxa conventionally placed in Mansuyiinae permits recognition of a previously unrecognized monophyletic subfamily Ceronocarinae new subfamily. As established herein, this kaolishaniid subfamily contains Satunarcus n. gen. and all genera previously recognized as Mansuyiinae. with the exception of Mansuyia itself. Ceronocarinae n. subfam. occur in middle Jiangshanian to middle Cambrian Stage 10 sedimentary rocks from Australia, South China, North China, and Sibumasu, with most genera endemic to Australia.

UUID: http://zoobank.org/618c5136-73f0-4912-a7d3-e56559d2a76c