A thin limestone tongue in the upper part of the Murdock Mountain Formation of northeastern Nevada contains abundant bryozoans of earliest Wordian age. This bryozoan fauna is close to the Kungurian-Kazanian boundary in Russia. These bryozoans are younger than those found in the Kaibab Formation of southern Nevada and slightly older than those in the Gerster Limestone of northern Nevada. This limestone tongue, herein referred to as the Stenodiscus beds, lies below the Thamnosia beds described by Wardlaw in the Murdock Mountain section of the Leach Mountains. This bryozoan-rich limestone tongue serves as a marker unit for mapping the Murdock Formation in the Leach Mountains.

Nine new species of bryozoans occur in the Stenodiscus beds of the Murdock Mountain Formation: Hinganella felderi, Neoeridotrypella schilti, Stenopora parvaexozona, Stenodiscus murdockensis, Dyscritella acanthostylia, Pseudobatostomella irregularis, Streblotrypa (Streblotrypa) elongata, Morozoviella praecurriensis, and Thamniscus erraticus, Hinganella felderi, Neoeridotrypella schilti, Dyscritella acanthostylia, and Streblotrypa (Streblotrypa) elongata are very similar to species described from Russia.

In a large collection of Wenlockian gastropods from north Siberia, a single small specimen shows the operculum in situ just within the aperture. In other morphologic features, particularly the presence of numerous spiral lirae on the shell, this species is similar to Silurian gastropods traditionally assigned to Oriostoma. Preservation of the operculum is far from perfect, but almost certainly it has paucispiral growth, rather than concentric or multispiral construction. This new species (Australonema varvarae n. sp.) is assigned to Australonema, previously known only from the Lower Devonian of Australia, primarily because of the form of the operculum. The material was obtained from just below a biostromal unit in a bed interpreted as an interreef lagoon in an area of locally relatively quiet water.

The extinct family Hylicellidae, as the ancestral group of modern cicadomorphans, had a wide distribution and a very high species-level biodiversity from the Triassic to Early Cretaceous. We herein report 11 new hylicellid specimens from the Jurassic Daohugou beds of Inner Mongolia, NE China, and execute geometric morphometric analysis (GMA) to elucidate their systematic position. Our GMA and subsequent morphometric statistics indicate that 10 of our new specimens can be compared to the holotype of Cycloscytina gobiensis, and one is new to science. Cycloscytina incompleta new species is erected based on this specimen, with the following discriminatory tegminal traits: C3 almost as long as and slightly narrower than C2, and the forking position of stem M distinctly migrates towards wing apex and much apicad of the stem CuA bifurcating. Additionally, Cycloscytina plachutai is herein transferred to the procercopid genus Procercopina, resulting in P. plachutai new combination. To date, just a few body structures of Hylicellidae have been revealed, and the new whole-bodied hylicellids reported herein provide some novel insights on the evolution of basal Clypeata. This study also emphasizes the use of morphometric analysis in the systematics of wing-bearing insects such as hylicellids.

UUID: http://zoobank.org/84a67eba-9b7c-4e27-a436-764802c4cdfb.

Diverse silicified trilobite faunas from the lower Wenlock to lower Ludlow of the Cape Phillips Formation, central Canadian Arctic, have been the subject of works by Perry and Chatterton (1977), Chatterton and Perry (1979), Adrain (1994), and Adrain and Edgecombe (1995, and in press). The present work describes a very minor component of these faunas, the family Phacopidae, which is nevertheless of considerable biogeographic interest.

Groomodiscus rossi n. gen. and sp., a bellerophontacean from the Ordovician of Nevada that uncoiled at maturity, is described and placed in the Gastropoda. The deep notch or sinus of the shell is interpreted to have functioned the same as a deep slit, and the new genus is placed within the tropidodiscinids. Uncoiling and thickening of the shell in the mature stage of growth is probably an indication of a fundamental change of life style to a sedentary mode. Fragmentary specimens of the final, uncoiled portion of the whorl resemble the apertural portion of hyoliths. From a functional viewpoint, compressed planispiral shells are concluded more likely to be gastropods than monoplacophorans.

The sponge Neoguadalupia oregonensis new species is described from the Upper Triassic Martin Bridge Formation in the southern Wallowa Mountains, Oregon. It is the first authenticated Triassic occurrence of the genus Neoguadalupia, previously known from the Permian of South China and suspected to occur in Upper Triassic of Nevada. This discovery provides evidence at the generic level of survival of a Lazarus taxon in an island-arc terrane of western North America.

The Bridgeboro Limestone, a rhodolith- and coral-bearing limestone in southwestern Georgia, has been assigned to the Vicksburgian Stage (Lower Oligocene) of the Gulf Coast based on the occurrence of the bivalves Chlamys (Anatipopecten) anatipes (Morton) and C. (Lyropecten) duncanensis Mansfield. This assignment is further substantiated by the recent recognition of the distinctive bryozoan Tubucellaria vicksburgica Canu and Bassler. The Bridgeboro also contains the larger foraminifera Lepidocyclina (Lepidocyclina) mantelli (Morton), L. (Nephrolepidina) yurnagunensis Cushman, and L. (Eulepidina) undosa Cushman, an assemblage indicative of the Lepidocylina (s.s.) subzone of the Eulepidina Zone of Early Oligocene age. These foraminifera are also characteristic of the Duncan Church beds of the Florida panhandle, and an assemblage of isolepidine and eulepidine Lepidocyclina also occurs in the Glendon Limestone of Alabama. On the basis of larger foraminifera, macroin vertebrates, and physical stratigraphic relationships, we propose that the Bridgeboro, Duncan Church, and Glendon are biostratigraphically and lithostratigraphically correlative. The Glendon Limestone has been previously assigned to nannoplankton zone NP22, and also occurs within the Cassigerinella chipolensis–Pseudohastigerina micra planktonic foraminiferal zone, both of Early Oligocene age. Based on correlation with the Glendon, the age of the Bridgeboro is thus Early Oligocene (Rupelian), middle Vicksburgian.

Species-level diversity and evolution of Palaeosinopa from the Willwood Formation of the Bighorn Basin is reassessed based on substantial new material from the Bighorn, Powder River, and Wind River basins. We recognize three species of Palaeosinopa in the Willwood Formation of the Bighorn Basin: P. lutreola, P. incerta, and P. veterrima. The late Wasatchian species P. didelphoides is not present in the Bighorn Basin. The Willwood species can be differentiated based only on size. P. veterrima is the most common and wide-ranging species and is the most variable in size and morphology: the stratigraphically lowest individuals are smaller, with narrower, more crestiform lower molars; whereas the highest are larger, with wider, more bunodont teeth. Although it could be argued that these represent distinct species, we demonstrate that this morphological evolution occurred as the gradual and mosaic accumulation of features, suggesting in situ anagenetic evolution. The two smaller species are present only low in the section (biochrons Wa0–Wa4) and show no discernable evolution in size or morphology. A new skeleton of Palaeosinopa veterrima from the Willwood Formation is described, and other new postcrania are reported. The skeleton is the oldest associated skeleton of Palaeosinopa known, yet it is remarkably similar to those of younger, more derived pantolestids, the primary disparities being minor differences in proportions of the innominate, femur, and tibia, and co-ossification of the distal tibia and fibula. Either P. incerta or P. lutreola was likely the ancestral population that gave rise to the other Wasatchian Palaeosinopa. Alternatively, P. veterrima may have migrated into the Bighorn Basin from the Powder River Basin.

A new wood-boring ichnospecies is described from transgressive (lagoonal) deposits of the Lower Cretaceous Sparky Formation (Mannville Group) in west-central Saskatchewan, Canada. Apectoichnus lignummasticans new ichnospecies is a trace fossil that occurs in a thin coal bed and that was emplaced in an in situ xylic substratum (woodground). The ichnofossil is thin, elongate, unbranched, and straight to gently curved with a circular cross section and uniform diameter. Apectoichnus lignummasticans n. isp. is similar in many respects to modern borings in wood that are produced by marine isopods, e.g., Limnoria lignorum Rathke, 1799, for feeding and refugia. The recognition of Apectoichnus lignummasticans n. isp. in the rock record aligns with the modern observation that fossilized wood-boring assemblages should display higher ichnofossil diversities than commonly reported. Additionally, the stratigraphic occurrence of Apectoichnus lignummasticans n. isp. in association with other evidence of marine deposition reaffirms that certain wood boring morphologies (i.e., ichnotaxa) are useful as indicators of marine transgressions.

UUID: http://zoobank.org/880e722f-8944-42d7-bc38-423cc5a46413

The proboscidean Gomphotherium is reported here from the Alajuela Formation of Panama. Gomphotherium was widespread throughout Holarctica during the Miocene, and the Panama fossil represents the extreme southernmost occurrence of this genus in the New World. Allocation of the Panama Gomphotherium to a valid species is impossible given both the fragmentary material represented and the taxonomic complexity of species assigned to this genus. In North America, Gomphotherium has a relatively long biochronological range from the middle Miocene (~15 Ma) to early Pliocene (~5 Ma). Based on morphological comparisons, the Panama Gomphotherium is either middle Miocene, thus representing the earliest-known entry of this genus into Central America, or late Miocene/early Pliocene, which challenges the currently accepted middle Miocene age of the Alajuela Formation as it has been previously reported from Panama.

Larval and juvenile growth stages of myoconchid bivalves (family Kalenteridae) are illustrated and described for the first time. Excellently preserved shells of Myoconcha crassa J. Sowerby, 1824 from the middle Bathonian (Middle Jurassic) clay/silt deposits of southern Poland reveal that the prodissoconch in this taxon is large (exceeding 350 µm in length) and characterized by a prominent, collar-like structure arising from the demarcation to the dissoconch. Similar prodissoconch morphology has not been described previously in any other bivalve genus. The large size and absence of a prodissoconch II strongly suggest a non-planktotrophic development of the larvae, indicating either simple lecithotrophy or long-term brooding and parental care for the larvae in this species. Consequently, the new discovery constitutes the earliest well-documented record of non-planktotrophic development in the Bivalvia. The shell of Myoconcha crassa is composed of an outer cross-lamellar layer and an inner complex cross-lamellar layer. This composition suggests that the Kalenteridae may be included in the Carditida rather than the Palaeoheterodonta or Anomalodesmata. The genus Pseudomyoconcha Rossi Ronchetti and Allasinaz, 1966 is rejected herein and considered as a junior synonym of Myoconcha J. Sowerby, 1824.

Upper Ordovician strata exposed from the Baiyanhuashan section is the most representative Late Ordovician unit in the northwestern margin of the North China Craton (NCC). In total, 1,215 conodont specimens were obtained from 24 samples through the Wulanhudong and Baiyanhuashan formations at the Baiyanhuashan section. Thirty-six species belonging to 17 genera, including Tasmanognathus coronatus new species, are present. Based on this material, three conodont biozones—the Belodina confluens Biozone, the Yaoxianognathus neimengguensis Biozone, and the Yaoxianognathus yaoxianensis Biozone—have been documented, suggesting that the Baiyanhuashan conodont fauna has a stratigraphic range spanning the early to middle Katian. The Baiyanhuashan conodont fauna includes species both endemic to North China and widespread in tropical zones, allowing a reassessment of the previous correlations of the Katian conodont zonal successions proposed for North China with those established for shallow-water carbonate platforms at low latitudes.

UUID: http://zoobank.org/7cedbd4a-4f7a-4be6-912f-a27fd041b586

Lovén's Law described the position of larger basicoronal ambulacral plates in echinoids. The smaller basicoronal plates form first in ontogeny. We restate Lovén's Law to describe the position of first ambulacral plates using Carpenter's ambulacra and left (L) or right (R) as: AR, BL, CR, DL, ER, with EA the pair of ambulacra both identical and adjacent. First ambulacral plates of the Cambrian edrioasteroid, Walcottidiscus, code identically. The transition from a tri-radiate 1-1-1 pattern to the 2-1-2 ambulacral pattern of Walcottidiscus and other pentaradiate Paleozoic echinoderms results in Lovén's Law. This provides an hypothesis for the origin of Lovén's Law and predicts its widespread occurrence among echinoderm classes.

The ‘BD different’ pattern of primary brachioles in pentaradiate glyptocystitoid Rhombifera results from subterminal branching of the ambulacra. The ontogenetic sequence was triradiate, then lateral ambulacra bifurcated, and finally second brachioles developed. Positions of second brachioles of pentaradiate glyptocystitoids code as AR, BL, CR, DL, ER. Other examples of Lovén's Law occur in Diploporita, Ophiuroidea, Edrioasteroidea, Edrioblastoidea, Holothuroidea, Ophiocistioidea, and Bothriocidaris. Our working hypothesis is that Lovén's Law arose with pentaradiality. An objective test requires a reliable independent landmark across all classes, which does not exist currently. Our hypothesis is only parsimonious if Lovén's Law arose just once in echinoderm evolution and is widespread within the phylum. So far, both conditions appear to be met, but edrioasteroid first ambulacral cover plates commonly exhibit an alternative Lovén-like pattern of AL, BL, CR, DL, ER, with AB the identical adjacent ambulacra.

UUID: http://zoobank.org/4c40d338-8bfa-4515-9037-934f3bbab153

X-ray CT scans at two different energies of three articulated specimens of Spathelopsis oakvalensis n. sp., a bivalve from the Bluefield Formation of the Mauch Chunk Group (Mississippian, Chesterian) from southeastern West Virginia, permitted observation and description of poorly known internal features of the shell, resulting in a reversal of the shell orientation alleged by past authors and concomitant reassignment of this problematic genus to the palaeotaxodont family Nuculanidae Adams and Adams. Distinctive posterior and anterior gapes in Spathelopsis suggest separation of inhalant and exhalant water streams, a characteristic associated with derived but not primitive palaeotaxodonts.

Among the abundant, well-preserved rhynchonellid brachiopods in the Upper Ordovician–Lower Silurian rocks of Anticosti Island, Fenestrirostra Cooper, 1955, one of the earliest camarotoechiid genera to appear in the fossil record, is probably of oligorhynchiid ancestry and seemingly endemic to the Anticosti Basin. The genus differs most obviously from other camarotoechiids in its peculiar costae, which are angular and strong posteriorly and flat and weak anteriorly.

Three successive species of Fenestrirostra, found in micritic mudstones and calcareous shales of the middle and upper Merrimack and Lower Gun River Formations, provide an example of gradualistic evolution. The most primitive species, F. primaeva, occurs only in the lower part of the middle Merrimack Formation; the descendant intermediate species, F. glacialis, occurs mainly in the upper part of the middle and in the upper Merrimack and in the lowermost Gun River Formations; and the descendant terminal species, F. pyrrha, occurs only in the lower Gun River Formation. Four major morphoseries distinguish the lineage: 1) change in the proportions and size of the shells; 2) increase in the number and concomitant loss of the costae from the anterior halves of the shells; 3) change in the orientation and reduction in the size of the hinge plates and hinge fossettes; and 4) change in the height of the median septum. The evolutionary modifications, estimated to have been accomplished in no more than 1 m.y., may have been adaptive responses to persistent low-energy marine conditions.

Biostratigraphically, the Fenestrirostra lineage provides the basis for three interval or range zones that straddle the Rhuddanian–Aeronian interstage boundary in the Anticosti Basin.

The genus Bimuria Ulrich and Cooper, 1942, is a biogeographically important member of middle and late Ordovician brachiopod faunas of the Callahan–Gazelle area in the eastern Klamath Mountains of northern California. In middle Ordovician deposits the genus is widespread and ranges from Nevada in the west to southwestern Siberia in the east; however, in late Ordovician beds it was previously known only in Sweden and Northern Ireland. In addition to the northern California occurrence reported here, new late Ordovician occurrences are also noted in east-central Alaska–Yukon Territory and Northwest Territories. Three species of Bimuria are described, including the new species, B. californiensis.

A preliminary survey of species described in the literature suggests that the ratio of the length of the dorsal adductor field to the length of the elongate area in the brachial valve decreases from middle to late Ordovician species, and thus may be of biostratigraphic value.

The remaining terrestrial gastropod fauna of the late Oligocene–early Miocene Cabbage Patch beds of western Montana is composed of nine new species, all from extant genera now occurring in the western United States: Vallonia berryi, [Succineidae] montana, Nesovitrea pulchra, Deroceras securis, D. mahiz, Punctum alveus, Polygyroidea montivaga, Oreohelix brandi, and Monadenia? n. sp. A, which is described from neanic material. All except the Monadenia? represent first occurrences of the respective genus in North America. The terrestrial fauna suggests that climatic and environmental conditions during the late Oligocene–early Miocene interval must have been very similar to those of the present. Two sizes of gastropod eggs, attributed to P. montivaga and V. berryi, were found at one locality. Monadenia? n. sp. A is of limited use, due to rarity, as an index fossil for the upper Cabbage Patch beds.

The Early Permian (late Sakmarian to early Artinskian) adrianitid ammonoid Nevadoceras steelei new genus and species occurs in a fauna containing the ammonoids Properrinites Elias, Prothalassoceras Böse, Daraelites Gemmellaro, Almites Toumanskaya, Bamyaniceras Termier and Termier, Akmilleria Ruzhencev, Agathiceras Gemmellaro, Metalegoceras Schindewolf, Stenolobulites Mikesh, Glenister, and Furnish, Crimites Toumanskaya, Neocrimites Ruzhencev and the conodonts Sweetognathus whitei (Rhodes) and Mesogondolella bisselli (Clark and Behnken). This fauna occurs in a concretionary interval within micritic basinal facies of the Dry Mountain trough at Portuguese Springs, White Pine County, east-central Nevada.

An extensive faunule of silicified calcareous sponges has been recovered from the Upper Guadalupian Reef Trail Member of the Bell Canyon Formation, from the Patterson Hills, in the southwestern part of the Guadalupe Mountains National Park in western Texas. This is the youngest silicified faunule of Permian sponges known from that area, and possibly the youngest from North America. It includes the hypercalcified ceractinomorph “sphinctozoans” Amblysiphonella sp., Tristratocoelia rhythmica Senowbari-Daryan and Rigby, 1988, Colospongiella permiana n. gen. and sp., Exaulipora permica (Senowbari-Daryan, 1990), Parauvanella minima Senowbari-Daryan, 1990, and the “sphinctozoans” Girtyocoelia beedei (Girty, 1909), Sollasia ostiolata Steinmann, 1882, Sollasiella reticulata n. gen. and sp., Ramosothalamiella divaricata n. gen. and sp., and Spica texana n. sp. Also present are Guadalupia zitteliana Girty, 1909, Guadalupia minuta n. sp., Lemonea cylindrica (Girty, 1909), and Lemonea micra Rigby, Senowbari-Daryan, and Liu, 1998. Aspiculate calcareous sponges include the “inozoids” Preperonidella rigbyi (Senowbari-Daryan, 1991), ?Djemelia sp., Radiotrabeculopora virga n. sp., Daharella ramosa Rigby and Senowbari-Daryan, 1996, Daharella pattersonia n. sp., Daharella crassa n. sp., and Newellospongia perforata n. gen. and sp. The problematic Lercaritubus problematicus Flügel et al., 1990 is tentatively included with the “inozoids.”

The new siliceous protomonaxonid demosponge Monaxoradiata lamina n. gen. and sp., is a moderately common sponge from the member. The new siliceous lithistid demosponges Chiastocolumnia cylindrica n. gen. and sp., Dactylites obconica n. sp., and Dactylites magna n. sp., the large hexactinellid sponge Toomeyospongia gigantia Rigby and Bell, 2005, and the new lyssacinosid Flexuospiculata hexactina n. gen. and sp., along with isolated large hexactines, are associated with these silicified calcareous sponges from the Reef Trail Member. Toomeyospongia gigantia Rigby and Bell, 2005, described earlier, is the only large complete hexactinellid sponge that is part of the Reef Trail Member assemblage.

The problematical Pulsatospongia obconica n. gen. and sp., whose taxonomic position is uncertain, along with an encrusting possible inozoid sponge, and spicule-lined ?burrows are also described as part of the fossil assemblage.

Significant faunal similarity occurs between this assemblage and those from several areas within the Paleo-Tethys Sea, especially with those from the Djebel Tebaga area of Tunisia. This suggests significant faunal exchange between the two regions, possibly resulting from strong trans-Panthalassan equatorial currents and a significant anti-cyclonic gyre within the Paleo-Tethys basin.

The generic name Petrostroma proposed by Stearn (1991) for a Paleozoic stromatoporoid with type species Petrostroma simplex (Nestor, 1966) is preoccupied by a calcareous sponge described in 1892 by Döderlein.