The Late Ordovician and Early Silurian conodont faunas of northeast Russia are described, based on 39 conodont-bearing samples collected from Kanyon, Padun, Tirekhtyakh, Maut, and lower Sandugan Formations at Mirny Creek and Ina River sections, Omulev Mountains. The faunas are represented by a total of 776 identifiable conodont specimens assigned to 35 species representing 25 genera, among which a new species, Periodon mirnyensis, is established. Based on graptolite zones at the same locality and other conodont faunas worldwide, the faunas are assigned to the Caradocian, early Ashgillian, late Ashigillian, early Llandovery, and late Llandovery. The Ordovician faunas belong to outer platform to upper slope facies with a North Atlantic Realm affinity; the Silurian faunas are from slope and basin facies. The conodont faunas are the first to be described from the Kolyma Terrane, which has an enigmatic paleogeographic position during the Early Paleozoic.

A review and revision of the Paleozoic proto-stomatopods results in the recognition of a new species of Tyrannophontes Schram, 1969, T. gigantion, from the Middle Pennsylvanian Mazon Creek, Essex biota. A new family, Daidalidae, and new genus, Daidal, are required to separate a previously recognized taxon, T. acanthocercus Jenner, Hof, and Schram, 1998. Both Perimecturus pattoni Peach, 1908 and Gorgonophontes cf. fraiponti (Schöllmann, 2004) appear at present to be best placed within Daidal, the latter as a new species, D. schoellmanni. The genus Gorgonophontes Schram, 1984 is allocated to a new family, Gorgonophontidae. Members of the family Tyrannophontidae reveal features of their maxillipeds that clearly relate them as a sister group to Unipeltata. A cladistic analysis of all known Paleozoic Palaeostomatopoda Brooks, 1962 and Archaeostomatopodea Schram, 1969 reveals a series of stem-group proto-mantis shrimp that lead to the crown-group Unipeltata Latreille, 1825.

Isorophid edrioasteroids representing a new genus and two new species are described from the Chesterian (Upper Mississippian) of Illinois and Maryland. Neoisorophusella lanei occurs in the Kinkaid Limestone of Johnson County, Illinois, and N. berryi occurs in the Greenbrier Limestone of Garrett County, Maryland. The problematic edrioasteroid species Hemicystites? carbonarius Bassler, 1935, from the Chesterian of southern West Virginia, is questionably assigned to Neoisorophusella.

The beetle Ceutorhynchus is used as a proxy for Eocene core Brassicaceae. The age of Brassicaceae has been strongly debated because their fossil record is scanty. There are four species of Ceutorhynchus inaffectatus species-group known in the Priabonian: Ceutorhynchus zerovae new species in Rovno amber and three in Baltic amber. There are numerous extant members of the group, all of which feed on core Brassicaceae. Together with differentiation of Brassicaceae-feeding Pierinae (Lepidoptera) in the Priabonian, the strong presence of Ceutorhynchus indicates at least an early Priabonian age of core Brassicaceae. The oldest fossil Brassicaceae is not known in the late Eocene of Europe, but was recorded in Montana, dated in some studies as late Oligocene, but recently as Priabonian (34 Ma). Ceutorhynchus zerovae n. sp. is very close to C. electrinus from Baltic amber.

UUID: http://zoobank.org/7f10761f-463d-44c5-9eef-bb4697bfb116.

Considerable numbers of exceptionally preserved conodont apparatuses with hyaline elements are present in the middle-upper Darriwilian (Middle Ordovician, Whiterockian) Winneshiek Konservat-Lagerstätte in northeastern Iowa. These fossils, which are associated with a restricted biota including other conodonts, occur in fine-grained clastic sediments deposited in a meteorite impact crater. Among these conodont apparatuses, the common ones are identified as Archeognathus primus Cullison, 1938 and Iowagnathus grandis new genus new species. The 6-element apparatus of A. primus comprises two pairs of archeognathiform (P) and one pair of coleodiform (S) elements. The 15-element apparatus of I. grandis n. gen. n. sp. is somewhat reminiscent of the prioniodinid type and contains ramiform elements of alate (one element) and digyrate, bipennate, or tertiopedate types (7 pairs). Both conodont taxa are characterized by giant elements and the preservation of both crowns and basal bodies, the latter not previously reported in Ordovician conodont apparatuses. Comparison of the apparatus size in the Winneshiek specimens with that of the Scottish Carboniferous soft-part-preserved conodont animals suggests that the Iowa animals were significantly larger than the latter. The apparatus of A. primus differs conspicuously from the apparatuses of the prioniodontid Promissum from the Upper Ordovician Soom Shale of South Africa although the apparatus architecture of I. grandis n. gen. n. sp. shows some similarity to it. Based on the Winneshiek collections, a new family Iowagnathidae in Conodonta is proposed.

The diagnosis of the shovel-tusked gomphothere genus Amebelodon has been subject to dispute since it was first established by Barbour in 1927. This dispute stems from a failure to evaluate the phylogenetic nature of two characters found in some specimens referred to Amebelodon: four lophs(ids) on some intermediate cheek teeth (M2 and M1) and internal dentinal rods within the lower tusks. These characters are considered diagnostic for the shovel-tusk gomphothere genera Platybelodon and Torynobelodon, and conflict with the traditional diagnosis of Amebelodon. Newly described specimens of Amebelodon and a detailed morphological analysis of one of the disputed characters, dentinal rods, indicate that the character states in the two shovel-tusker groups are analogous. The genus Amebelodon is rediagnosed to take into account this new information.

The rediagnosis of Amebelodon is taxonomically recognized by the designation of a new subgenus, Amebelodon (Konobelodon), which includes all Amebelodon specimens convergent with Platybelodon and Torynobelodon. A new species, A. (Konobelodon) britti, is established that includes all specimens of this subgenus from North America. Specimens from the Moss Acres Racetrack site (Hemphillian) in northern Florida are used in the description of this species.

Well-preserved polycystine radiolarians, representing a new species in the family Entactiniidae, were recovered from subtidal micrites and bioclastic micrites of the Upper Cambrian (Glyptagnostus reticulatus trilobite zone) Bitiao Formation, western Hunan, China. Confirming earlier, questionable reports of Cambrian Radiolaria, these fossils place the first appearance of the group somewhat before its Ordovician emergence as a principal constituent of the oceanic silica cycle, but long after the Proterozoic diversification of protists.

Since 1908, the peculiar North American primate Picrodus Douglass, 1908 (Picrodontidae; Plesiadapiformes) has been thought to contain only a single species, P. silberlingi Douglass, 1908, of late Paleocene age. However, new collections from the Paskapoo Formation, Alberta, Canada, reveal that instead a rich complex of Picrodus species lived during the Paleocene. Three of these, Picrodus calgariensis, P. canpacius, and P. lepidus, are described herein as new. Others, represented by more fragmentary specimens from Canada and the United States, are included in this paper, but are not named. P. calgariensis, from Who Nose? (late Torrejonian), Calgary, is the most primitive known species of Picrodus, having molars with little crenulation of the enamel. P. canpacius, from Cochrane 2 (earliest Tiffanian), northwest of Calgary, most resembles P. silberlingi sensu stricto, but differs in P4 structure, denser enamel crenulation, and weaker molar cusps. P. lepidus, from DW-2 (middle Tiffanian), near Red Deer, is the most advanced, having, for example, a two-rooted P4, tiny p3, and single-rooted p4. At least two of these species also occur in the United States, documented by fossils referred to P. silberlingi by previous workers. Dental evolution within Picrodus seems marked by several trends, including increase in size of i1, simplification of P4, reduction of molar cusps and crests, enlargement of the horizontal occlusal surfaces of the molars, and greater crenulation of enamel. From present knowledge, Zanycteris paleocenus Matthew, 1917 is dentally more primitive than Picrodus, Draconodus Tomida, 1982 is a valid genus, and picrodontids probably originated from “purgatoriid-grade” plesiadapiforms in earliest Paleocene time.

Skeletonized protists (or protoctists) appear as body fossils in the late Neoproterozoic and the lower Cambrian (e.g., Allison and Hilgert, 1986; Lipps, 1992; Culver, 1994; Porter et al., 2003) and are well known from the post-Cambrian fossil record. However, molecular data and biomarkers of groups such as ciliates and foraminiferans indicate a long Precambrian history unrecorded by fossils, and also suggest that foraminiferans were important components of Neoproterozoic protistan communities (e.g., Summons et al., 1988; Wright and Lynn, 1997; Lipps, 2003; Pawlowski et al., 2003). The recent discovery of agglutinated microfossils interpreted as foraminiferans from the Neoproterozoic of Uruguay (Gaucher and Sprechmann, 1999) supports the inferences made from molecular data. Although foraminiferans are known for certain since the earliest Cambrian (e.g., McIlroy et al., 2001), their diversity and variability during the Cambrian is limited to a few agglutinated unilocular genera (e.g., Lipps, 1985; Culver, 1991, 1994; Cope and McIlroy, 1998; Zhigulina, 1999; McIlroy et al., 2001). Among these, Platysolenites Pander, 1851 is one of the best known genera because it has a wide distribution and high abundance in lower Cambrian sediments, especially those of Baltica and Avalonia (e.g., Rozanov, 1983; Lipps and Rozanov, 1996; McIlroy et al., 2001). Whether Platysolenites has an affinity with the foraminifera has been questioned by some authors (e.g., Eichwald, 1860; Rozanov, 1983; Brasier, 1989b), but the similarity of its morphology and wall structure to the foraminiferan genus Bathysiphon Sars, 1872 (e.g., Glaessner, 1978), and the presence of proloculi in Platysolenites (e.g., McIlroy et al., 2001) is strong evidence in favor of an affinity with the foraminifera. It should be emphasized that the preservation of proloculi in Platysolenites is rare, reported only in a few cases (McIlroy et al., 1994, 2001; Lipps and Rozanov, 1996) prior to this one.

An Erpetopus trackway recorded in the Lower Permian Collio Formation (Orobic Alps, northern Italy) is investigated as a source of data to reconstruct ancestral patterns of locomotion in eureptiles. The inferred small-sized captorhinid-“protorothyridid” producer cut an inclined muddy surface dragging its front limb digits, tail, and belly on the ground. Integrating ichnological and anatomical data we suggest that small captorhinids (“protorothyridids”) locomotion was performed with an obligatory, rigid sprawling posture with the trunk only slightly lifted from the substrate in a low, sprawled ‘belly walk’.

A new decapod crustacean species, Shinkaia katapsyxis, is reported from the Eocene Humptulips Formation of western Washington, USA. The specimens were collected from a hydrocarbon seep deposit that has been well-documented and contains a well-described molluscan fauna. The new occurrence extends the geologic range of the genus Shinkaia Baba and Williams, 1998, and subfamily Shinkaiinae Baba and Williams, 1998, into the Eocene from its only other known occurrences in hydrothermal vent environments in the Pacific Ocean. The range extension of an extant decapod genus into the Eocene is not uncommon and adds to the evidence that the Decapoda may be unusually resistant to extinctions and are distinctly conservative evolutionarily.

A sinkhole locality in the Wasatch Plateau has yielded Utah's first record of the American mastodon. At nearly 3,000 m this fossil-bearing site denotes the highest elevation yet reported for Mammut americanum, and demonstrates that mountainous terrain was not a barrier to dispersals. A presumably preferred habitat of spruce-fir open forests, similar to that in the area today, was present during the time of the mastodons reported here. Two incomplete individuals of M. americanum are the only fossils that were found in the sinkhole. Entrapment appears to have been the cause of death. Since the record of M. americanum in western North America is sparse, the present find has added significance in providing more information about the nature of this animal. A possible association of a recovered spear point fragment near the fossils indicates the possibility that man and mastodon were contemporaneous here. Three independent datings were run on mastodon bone. Two based on carbon-14 yielded dates of 7,090 ± 200 yr B.P. and 7,590 ± 100 yr B.P., while the third, using the racemization process, indicated an age of less than 10,000 yr B.P.

A small assemblage of shelly fossils, dominated by the brachiopod Treptotreta jucunda and the bradoriid arthropod Mongolitubulus aspermachaera new species is described from a Furongian limestone of Västergötland, south-central Sweden. Mongolitubulus aspermachaera is represented in the assemblage by individual valves and numerous, ornamented spines. Valves and spines share identical ornament and microstructure leaving no doubt that the isolated spines were once attached to the bradoriid valves. Mongolitubulus aspermachaera adds to the increasing list of spinose Cambrian bradoriid arthropods, and Mongolitubulidae new family is erected here to incorporate the genera Mongolitubulus, Tubuterium and Spinospitella. Mongolitubulus aspermachaera represents the youngest member of the new family and supplements the biodiversity of bradoriids in the Furongian, an interval when bradoriid diversity is considered to be very much on the decline. The brachiopod Treptotreta jucunda described predominantly from the ‘middle' to ‘late' Cambrian of Australia is here documented for the first time from outside Gondwana, dramatically extending the biogeographical range of the species. Other elements of the faunal assemblage include typical Baltic Furongian representatives, such as the trilobite Parabolina, the agnostoid Agnostus and the phosphatocopids Hesslandona and Vestrogothia.

Many peculiarities of growth and development in colonial metazoans are related to the fact that a true colony is a clone, composed of genetically identical individuals reproduced asexually from a single founding individual. In fossil colonies the close relationship of individuals may be difficult to prove, but it must be assumed for analysis to be meaningful.

Intercolony variation is due to the interaction of genetic and environmental controls as in solitary organisms. Intracolony variation may be very limited because of the lack of genetic variation, but microenvironmental differences (situation within colony) may cause enough individual variation to mask the restrictive effect of genetic similarity.

Study of the number of major septa in some Devonian solitary and colonial rugose corals shows significantly less variation within colonies than within “populations” or species of colonial or solitary forms. Greater variation within some colonies may result from either genetic or mechanical accidents. Septal number and diameter are closely correlated in populations and species, but analyses of individuals within colonies frequently show weak or no correlation. Available data suggest: 1) that septal-number variation may be genetically limited in rugose corals and 2) that the general assumption that number of septa is a function of diameter may be in error.

Two new fossil worms are described from the Lower Cambrian Kinzers Formation of southeast Pennsylvania. Both are unique specimens. Kinzeria crinita new genus and species has a body divided into three regions. The head bears a prominent set of elongate tentacles, presumably employed for feeding. The elongate trunk tapers slightly in a posterior direction. It contains a prominent intestinal tract, the contents of which indicate a deposit feeding habit. The tail is an expanded structure, with either a spatulate or sagittate outline. The mode of life of K. crinita is uncertain, but the animal may have been semi-sedentary. Atalotaenia adela new genus and species is more poorly known, lacking the anterior. The preserved body is vermiform, with external annulations and a rounded posterior. There is a prominent internal strand, consisting of a probable intestine and an associated fibrous unit, possibly representing muscles. This worm may have been infaunal. These discoveries extend further our understanding of the ancient diversity of Laurentian Burgess Shale-type faunas. In common with the Burgess Shale itself and the Sirius Passet fauna (Peary Land, Greenland) the location of fossil-Lagerstätte [see Shields (1998) for a discussion of the terminology of Lagerstätten] of the Kinzers Formation adjacent to a prominent escarpment reinforces earlier evidence of the paleotopography exerting an important control on the distribution of Burgess Shale-type faunas. Whether this is a result of localized faunal abundances or taphonomic control is, however, uncertain.

The family Mixosauridae Baur, 1887 is a dominant group of Middle Triassic ichthyosaurs. Its generic composition has been controversial, but recent findings from southern China enabled Jiang et al. (2006) to recognize two monophyletic taxa within the clade, suggesting the presence of two genera within the family, namely Mixosaurus Baur, 1887 and Phalarodon Merriam, 1910. The latter genus, which was invalidated at one point (Nicholls et al., 1999; McGowan and Motani, 2003), was recently resurrected by Schmitz (2005) by validating its type species. Mixosaurus is Tethyan in distribution, whereas Phalarodon had been known mostly from North America and Spitsbergen, apart from a possible juvenile from Switzerland (Brinkmann, 1997, 1998). More recently, Jiang et al. (2003) reported a largely complete, yet poorly preserved skeleton as the first record of the genus Phalarodon from Asia and referred it to Phalarodon sp. However, important synapomorphies were not clearly identified, and evidence has since emerged that the specimen had been tampered with by farmers after it was collected. In the light of the cladistic analysis by Jiang et al. (2006), the referral of the specimen to the genus Phalarodon is questionable.

Metrarabdotos Canu, 1914 and the related genera Escharoides Milne Edwards, 1836b, Adeonellopsis MacGillivray, 1886, and Reptadeonella Busk, 1884 were key taxa in the decline of Bryozoa with erect, arborescent colonies and concomitant increase in numbers of species with encrusting colonies in the late Paleogene and Neogene of tropical America. In particular, the abundance, continuity of occurrence, and diversity of Metrarabdotos before its decline have made this genus, over the past 20 years, a model taxon for detailed morphometric studies of fine-scale evolutionary tempo and mode. During the same period, significant new occurrences of both Metrarabdotos and its near relatives have been documented with detailed collections from tropical American areas not represented in the original studies.

In this paper we present a complete reanalysis of the original morphometric data (Cheetham, 1986a), incorporating the new tropical American material and comparative material of selected Metrarabdotos species from Europe and Africa in order to formalize the taxonomy of the genus, many species of which have been in open nomenclature since 1986, and to explore their possible phylogenetic relationships to each other and to Escharoides, Adeonellopsis, and Reptadeonella. The new analysis, with procedures slightly modified from those used in the original analysis, is based on more than twice the number of specimens and 20% more morphological characters. Although the results include changes in species assignments for 13% of the specimens in the original analysis, the pattern of intraspecific morphological stasis previously identified in the tropical American Neogene species, and thus the concomitant interpretation of evolutionary tempo and mode, are unaltered.

Cladistic analysis resulted in a single most parsimonious tree for the 22 tropical American Metrarabdotos species, arranged in two monophyletic crown groups and a paraphyletic stem group. The stem group, ranging from latest Eocene to late Early or early Middle Miocene in age, includes four species, two of which are new: M. aguilerai from Venezuela and M. hispaniolae from the Dominican Republic and Haiti. Crown group A comprises seven species occurring in deposits of Late Miocene to Recent age, four of which are new: M. arawakorum from Venezuela; M. boldi and M. saundersi from the Dominican Republic; and M. coatesi, which occurs in the Dominican Republic, Costa Rica, and Panama. Crown group B, comprising 11 species, ranges from Early Miocene to Recent and includes five new species: M. cubaguaense from Venezuela; M. vokesorum from the Dominican Republic, Costa Rica, and Panama; and M. tainorum, M. jungi, and M. lopezense from the Dominican Republic. Incorporation of six European and African (eastern Atlantic) species, ranging in age from Early Miocene to Recent, into cladograms with the tropical American species produced more variable results in terms of both numbers of alternative trees and the positions of the tropical American species in them. One of these species, M. thomseni from the Pleistocene of Greece, and possibly a second, M. cf. M. maleckii Cheetham, 1968 from the Miocene of the Czech Republic, are new. With one exception, the eastern Atlantic species were placed in more or less basal positions in one or the other of the crown groups, suggesting that, as hypothesized by Cheetham (1968), the “Old World” and “New World” species of Metrarabdotos represent largely independent radiations. The exception is the living species M. cookae Cheetham, 1968, from West Africa and the Cape Verde Islands, which is placed unequivocally in a terminal position in crown group B. Although the three groups of tropical American species correspond in part to subgenera of Metrarabdotos erected by Cheetham (1968), the paraphyly of the stem group and the unresolved identity of the type species of the subgenus apparently corresponding to crown group A suggest that formalizing the taxonomy of these groups is unwarranted at present.

A further cladistic analysis, incorporating the three groups of Metrarabdotos species and Escharoides, Adeonellopsis, and Reptadeonella, yielded two trees, both of which support Cheetham's (1968) hypothesis that Metrarabdotos is more closely related to Escharoides than to Adeonellopsis and Reptadeonella. Escharoides is represented in tropical American Neogene deposits by two species, one of which, E. guraboensis from the Dominican Republic, is new. Of the six tropical American Neogene species of Adeonellopsis, four are new: A. cribrospiramen and A. guraboensis from the Dominican Republic, A. limonensis from Costa Rica, and A. antilleana from Cuba and Jamaica. Three of the six tropical American Neogene species of Reptadeonella, R. buddae from the Dominican Republic, R. collinsae from the Dominican Republic, Panama, Costa Rica, and the southeastern United States, and R. buricaensis from Panama, are also new.

Two four-shelled species characterized by a pylome-bearing outermost shell—Sphaeropyle robusta and its descendant, Sphaeropyle langii—are selected for morphological study. Both species are morphologically identical to three-shelled Actinomma morphotypes, morphotypes A and B, respectively. Furthermore, the number of pores on half a circumference of the primary cortical shell, the distinguishing feature between Sphaeropyle robusta and Sphaeropyle langii, accounts for the same between Sphaeropyle robusta and morphotype A, and between Sphaeropyle langii and morphotype B. It suggests that the three-shelled morphotypes A and B are juvenile forms of the four-shelled Sphaeropyle robusta and Sphaeropyle langii, respectively. This is strongly supported by the same stratigraphic distributions of each pair. The quantitative analysis of morphological variations in both species also revealed that they have nearly identical morphology, except for the number of pores on half a circumference of the primary cortical shell. In addition, the size range of primary and secondary cortical shells and the range of the number of radial spines increase in Sphaeropyle langii, while the length range of radial spines decrease.

Blastulospongia is an enigmatic siliceous fossil with affinities proposed amongst both the sphinctozoan-grade sponges and radiolarians. Blastulospongia polytreta n. sp. extends the record of this genus into the Lower Cambrian (Shuijingtuo Formation) and represents its first occurrence in China (Taishanmiao section, Hubei Province). It differs from previously described species in size and pore spacing. The first evidence for benthic attachment is presented. A relationship with sphinctozoan-grade sponges is considered unlikely, but firm support for a place in the radiolarians is lacking.