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The Mississippian rugose corals from Alabama housed in several museums in that state are revised on the basis of current knowledge of this subclass. Fifteen species belonging to 10 genera have been identified; three species are new, including Zaphrentites lacefieldi, Palastraea cullmanense, and Siphonophyllia alabamaense. Four coral assemblages characterize four stratigraphic subdivisions of the Mississippian in Alabama: Osagean, Meramecian, lower Chesterian, and upper Chesterian. Corals are abundant in some units but diversity is quite low in all assemblages. The level of endemism is very high, except for the lower Chesterian assemblage, which contains some western Paleotethyan forms. Two possible coral evolutionary lineages have been identified.
We used 57 morphometric characters to discriminate 17 extant and fossil Cupuladria species and analyzed their phylogenetic relationships in relation to extant Discoporella species. Data were gathered from 496 extant and fossil Cupuladria specimens ranging in age from early Miocene to Recent and distributed from the Caribbean to tropical eastern Pacific. A first series of discriminant analyses distinguished three morphological groups: Cupuladria with vicarious avicularia, Cupuladria without vicarious avicularia, and Discoporella. Further discriminant analyses identified 17 species of Cupuladria. Cladistic analyses of these three groups yielded four equally parsimonious trees. All of the consensus trees exhibited the same topology, dividing the 25 tropical American cupuladriids into four distinct monophyletic clades, including Discoporella, and are consistent with previous molecular phylogenies except that there are no molecular data for the CV2 clade. Diversification of species was higher in the CV1 and CV2 clades than CNV clade, and involved mostly Caribbean species. Cupuladria with vicarious clade 1 (CV1) includes: C. monotrema, C. pacificiensis, C. exfragminis, C. cheethami, C. biporosa, and four new species: C. pervagata, C. floridensis, C. colonensis and C. dominicana. Cupuladria with vicarious clade 2 (CV2) includes: C. multesima, C. incognita, and three new species C. collyrida, C. veracruxiensis and C. planissima. Cupuladria clade without vicarious (CNV) includes: C. surinamensis, C. panamensis, and one new species C. gigas. The stratigraphic occurrence of species is consistent with cladogram topology within clades. However hypothesized cladistic relations among clades are the reverse of their stratigraphic occurrence with younger clade CNV appearing as the hypothetical ancestor of the two older clades CV1 and CV2. More extensive collections of early to middle Miocene specimens of Cupuladria and Discoporella will be required to resolve this apparent paradox.
Small round pits and holes in fossil skeletal material are found in a wide variety of invertebrate substrates from diverse environmental settings. They are associated with parasitism, predation and commensal attachment. Four ichnogenera have been proposed for these trace fossils: Sedilichnus Müller, Oichnus Bromley, Tremichnus Brett and Fossichnus Nielsen, Nielsen and Bromley. Previous authors have established that Tremichnus is a junior synonym of Oichnus. Herein we show that Oichnus and Fossichnus are junior synonyms of Sedilichnus.
Sedilichnus, as defined herein, includes 10 ichnospecies. Sedilichnus spongiophilus, S. simplex, S. paraboloides, S. ovalis, S. coronatus, S. gradatus, S. halo, S. asperus, S. excavatus and S. solus. Consistent with previous work Sedilichnus ichnospecies are defined solely by morphological criteria and not by a priori assumptions regarding depositional environment or tracemaker. Thus, this ichnotaxon is recognized in both marine and continental settings on a wide variety of invertebrate skeletal tests. As is true with many ichnotaxa, Sedilichnus ichnospecies represent end-members in morphological spectra, however each ichnospecies is clearly differentiable from the others.
Sedilichnus spongiophilus are circular, non-penetrative pits in shells. Sedilichnus paraboloides are penetrative holes with spherical paraboloid forms and typically have larger external openings and smaller internal openings. Sedilichnus simplex are simple cylindrical borings that have both penetrative and non-penetrative forms. Sedilichnus coronatus differ from other forms by the presence of an etched or granular halo surrounding the boring. Sedilichnus gradatus have two concentric parts, an outer boring and an inner shelf of smaller diameter. Sedilichnus ovalis and S. asperus are both oval in outline differing in the presence of tapering paraboloid margins in S. ovalis and margins perpendicular to the substrate in S. asperus. Sedilichnus excavatus and S. solus are primarily non-penetrative and differ from other Sedilichnus by the presence of central, raised bosses or platforms. These two ichnospecies differ in the shapes of their external walls and the proportional thickness of the bounding groove.
A tectonically undeformed portion of the lower part of La Laja Formation is exposed at Cerro El Molle near San Juan, Precordillera of western Argentina. It consists of shallow-water, variably argillaceous lime mudstone and sporadically interbedded bioclastic grainstone deposited in an inner shelf setting. The El Estero Member and the basal 0.2 m of the Soldano Member contain a trilobite fauna of olenelloids and ‘simple' ptychoparioids indicative of the early Cambrian (series 2, stage 4; Dyeran stage of Laurentia). The succeeding 50 m of the lower Soldano Member yield trilobites characteristic of the early middle Cambrian (series 3, stage 5; Delamaran stage of Laurentia). In ascending order of occurrence, Amecephalus arrojosensis, Kochiella maxeyi and Eokochaspis nodosa, along with several other taxa, including Ptychobaba n. gen. (type species Ptychoparella buttsi), belong to the traditional lower Plagiura–Poliella Biozone. However, while this fauna is similar to that of the Great Basin, the nominative species of the Eokochaspsis nodosa and overlying Amecephalus arrojosensis biozones recognized in southern Nevada occur in reverse order in the Soldano Member. This suggests that the ranges of these species overlap, thereby reducing the temporal resolution in the Precordillera into a combined Amecephalus arrojosensis–Eokochaspis nodosa Biozone. Argillaceous lime mudstones at the top yield Mexicella mexicana, indicative of the Mexicella mexicana Biozone recognized in the Great Basin, which is equivalent to the traditional Albertella Biozone of Laurentia. Because corynexochids are almost absent, the low-diversity ‘kochaspid'-dominated biofacies appears to typify the platform interior. The fauna is entirely Laurentian in composition, reinforcing notions of a close proximity of Cuyania to Laurentia during the Cambrian that enabled faunal migration and interchange. The absence of a late early Cambrian to early middle Cambrian hiatus correlative with the Hawke Bay Event, however, suggests no close affinity to the Iapetus-facing margin of eastern Laurentia.
The upper part of the Santa Rosita Formation (Ordovician, Tremadocian) in the Nazareno area, Cordillera Oriental, northwestern Argentina, records the vertical passage of high-energy, shallow water platform environments to offshore settings. Eighteen trilobite species are described from this locality for the first time. Although the taxa from the lower part of the succession (Leptoplastides sp., Asaphellus sp.) are scarce and non-age diagnostic, those from the upper part include diverse assemblages partially assigned to the late Tremadocian Notopeltis orthometopa Zone. Systematic descriptions of several species (Geragnostus nesossii Harrington and Leanza, G. callaveiformis Harrington and Leanza, Asaphellus jujuanus Harrington, Notopeltis orthometopa [Harrington], Mekynophrys nanna Harrington, Ceratopyge forficuloides Harrington and Leanza, Apatokephalus tibicen Přibyl and Vanĕk) are improved, the genus Nileus Dalman (including N. australis n. sp.) is first reported from the Tremadocian of western Gondwana, and new species of Asaphellus Callaway (A. nazarenensis n. sp.), Conophrys Callaway, and Apatokephalus Brøgger are described. The trilobites have their closest affinities with faunas from Norway and Sweden. Notopeltis orthometopa and Mekynophrys nanna are restricted to the uppermost part of the succession, well above the first records of most other trilobites recognized.
Testudo antiqua is one of the few fossil turtle names to have survived the past 200 years of taxonomic reshuffling with its original genus and specific epithet intact. The nine currently known specimens were collected from the middle Miocene Hohenhöwen locality in southern Germany. Because the available Hohenhöwen material was never fully described, we here completely document all known specimens. It is unclear which of these specimens formed the original T. antiqua type series, so we herein selected the best preserved representative as the neotype. A phylogenetic analysis places T. antiqua in a basal polytomy within the clade Testudo, indicating that T. antiqua may represent the ancestral morphology of Testudo. As with a number of other published studies, ours was unable to resolve relationships between the three extant Testudo lineages (the hermanni-group, the graeca/kleinmanni/marginata group, and the horsfieldii-group). Finally, with a view toward locating more turtles and in order to better understand the geological and ecological context of these tortoises, we visited Hohenhöwen several times to search for the original collection sites, but we were unable to locate the original fossil quarries described in the literature.
The early Miocene site of Wadi Moghra, Qattara Depression, Egypt, is important for interpreting anthracothere (Mammalia, Artiodactyla) evolution, because the Moghra sediments preserve a higher diversity of anthracotheres than any other pene-contemporaneous site. New specimens from Moghra are described and form the basis for the systematic revision of Moghra anthracotheres provided here. Among the important discoveries recently made at Moghra is the first complete skull of Sivameryx moneyi. Other new specimens described here include two new species of Afromeryx, and a new genus and species, all of which are unique to Moghra. A review of biogeographic information supports the conclusion that three of the Moghra anthracotheres (Brachyodus depereti, B. mogharensis, and Jaggermeryx naida, n. gen. n. sp.) are members of late surviving lineages with a long history in Africa, while three other species (Afromeryx grex, n. sp., A. palustris, n. sp., and Sivameryx moneyi) represent more recent immigrants from Eurasia.
The Antiklinalbugt Formation of northeast Greenland comprises peritidal to subtidal carbonate sediments, deposited in shallow shelf settings during an early Tremadocian transgressive-regressive megacycle. The succession of shales and microbial, muddy and grainy limestone, with minor dolostone at the base and top, terminates at the cryptic Fimbulfjeld disconformity. The formation has yielded trilobites collected on Ella Ø, Albert Heim Bjerge, and Kap Weber by C. Poulsen (1920s and 1930s), J. W. Cowie and P. J. Adams (1950s), and during recent field studies in 2000 and 2001. The fauna includes dimeropygids Tulepyge cowiei and T. tesella n. spp., hystricurids Millardicurus and Hystricurus, and several species of Symphysurina. Micragnostus chiushuensis (Kobayashi, 1931) is rare, as are Chasbellus sp., Clelandia sp., and Lunacrania?. The presence of several Symphysurina species places the Antiklinalbugt Formation within the Symphysurina Zone. Chasbellus indicates the upper (lower Ordovician) part of the Symphysurina Zone for the lower upper Antiklinalbugt Formation. Conodonts place the middle lower formation in the Cordylodus intermedius conodont Biozone, the lower upper part in the Cordylodus angulatus conodont Biozone and the uppermost part in the Rossodus manitouensis conodont Biozone. This combined fauna is characteristic of the upper Skullrockian Stage of the Ibexian Series, with the lower part of the Antiklinalbugt Formation lying within the uppermost Cambrian of North America, and the upper part within the lower Ordovician. The entire formation lies within the global Tremadocian Stage of the early Ordovician.
The cortical structure of the green anchicodiacean alga Anchicodium in the Pennsylvanian Dueñas Formation of the Cantabrian Zone (northwestern Spain) is described and illustrated. Anchicodium is characterized by a broad phylloid or leaflike calcified thallus, consisting of a bilateral cortex and a poorly calcified central medulla. The organization and morphology of the cortical system have been revealed with great detail using cathodoluminescence microscopy. Anchicodium cortex is composed of up to three (four?) orders of dichotomized branched cortical siphons that are usually swollen at the center; primary siphons are bulbous and are followed by elongate cylindrical siphons. Cortical siphons are preserved as dull-bright luminescent molds filled with micrite or microsparite, and contrast sharply with the surrounding non-luminescent calcite infilling the intersiphonal spaces, originally occupied by aragonite. Anchicodium in the Dueñas Formation exhibits a variety of preservational stages. Through a compilation of the taxonomic nomenclature and morphologic re-interpretations, it is concluded that some late Paleozoic anchicodiacean algae might represent diagenetic stages of Anchicodium or Eugonophyllum without any taxonomic significance. This conclusion is suggested particularly for the taphotaxon Ivanovia.
A new Early Cretaceous neosuchian crocodyliform is recognized on the basis of two skulls and postcranial material collected from the late Aptian Twin Mountains Formation at Proctor Lake, central Texas. The new species, Wannchampsus kirpachi, is distinguished by a unique combination of characters including an enlarged third maxillary tooth, internal choanae bordered anteriorly by the palatines and by the pterygoids posteriorly and laterally, anterior margin of the choanae situated at the posterior edge of the suborbital fenestrae, a median crest along the midline of the parietal and frontal, and procoelous vertebrae. A phylogenetic analysis recovered the new taxon as the sister to the ‘Glen Rose form,' an undescribed taxon of neosuchian. Together, with Shamosuchus, Batrachomimus, and Rugosuchus, they form a monophyletic group, Paralligatoridae, that is the sister clade to Eusuchia within Neosuchia. The Proctor Lake taxon and the undescribed yet widely discussed ‘Glen Rose form' are referable to the same genus.
Paleontologists have long speculated that the bizarre, giant Ordovician gastropods MacluritesLe Sueur, 1818 and MaclurinaUlrich and Scofield, 1897 lived more like suspension-feeding oysters than typical algivorous snails. Geometric and eigenshape morphometrics demonstrate the plausibility of this lifestyle, but with a twist. The apertures of these gastropods were small ellipsoids when young, transitioning rapidly to polygonal morphologies at maturity, with angulations (sinuses) occurring in regions associated with development of mature ctenidia (gills) and enhanced stability on the seafloor. Combined with knowledge of extant suspension-feeding gastropods and functional and phylogenetic analysis of the anatomy of other fossil relatives, this ontogenetic pattern suggests these snails began life as typical mobile algae-grazers, but switched to sedentary suspension-feeders as they aged.
Palaeoaplysina is an enigmatic platy macrofossil with a cellular skeleton and internal canal system common to upper Carboniferous–lower Permian reefs of the northern hemisphere. Its rapid flourishing from the Moscovian and subsequent extinction near the end of the Sakmarian, as well as its unique combination of physical features, are poorly understood. In addition to Palaeoaplysina reefs forming major petroleum exploration targets in Russia, Palaeoaplysina is abundant and well preserved in the Sverdrup Basin in the Canadian Arctic Archipelago. A new genus of Palaeoaplysinaceae, Eopalaeoaplysina n. gen., is also widespread in the Sverdrup Basin and identified based on a simple morphology with broad canals distributed in roughly even rows. The distribution of paleoaplysinids in strata from the Moscovian to the Sakmarian in the Sverdrup Basin reveals Eopalaeoaplysina and Palaeoaplysina represent two distinct reef-building forms with an increase in complexity over time. The aragonitic composition of Palaeoaplysina, in addition to its distribution within the photic zone and differentiated cellular skeleton, suggests paleoaplysinids were ancestral red algae. Palaeoaplysina occurs in both low-energy back-reef and higher-energy reef front facies. Preserved thin edges of Palaeoaplysina plates indicate it was encrusting, at least in low-energy conditions. The exclusion of Palaeoaplysina from the late Paleozoic tropics and the southern hemisphere, its rapid appearance and proliferation, and its eventual extinction may point towards an evolutionary niche optimized for warm-water conditions at unusually high latitudes along the western margin of Pangea.
A new species of Oikozetetes, O. mounti n. sp. is described from the upper Mernmerna Formation (equivalent to Cambrian Series 2) in the eastern Flinders Ranges, South Australia. Description of both shell morphotypes (morph A and B) from the same stratigraphic horizon favors the interpretation of a two-shelled scleritome for Oikozetetes. Identification of at least two types of halkieriid sclerite (palmates and siculates) in stratigraphic association with the Halkieria-like shells of Oikozetetes suggests that these elements are derived from the same scleritome. This provides evidence against previous suggestions that the Gondwanan species was aspiculate; the scleritome arrangement is interpreted to be similar to Halkieria evangelistaConway Morris and Peel, 1995 and supports placement in the family Halkieriidae Poulsen, 1967. Comparison of modes of accretionary growth in Oikozetetes shell morphotypes to Halkieria shells and terminal plates in modern polyplacophorans, supports a scleritome model that places shell morphs A and B in posterior and anterior locations, respectively, along the axis of the body.
Early Cretaceous fossilized leaves assignable to the extinct seed plant order Bennettitales occur within an exceptionally diverse Early Cretaceous (Valanginian) flora of anatomically preserved plant fossils at Apple Bay on Vancouver Island, British Columbia, Canada. One of the bennettitalean leaf types has an entire margin, with laminae that are attached near the adaxial surface of the midvein. Leaves are 10–15 mm wide with an adaxial surface that shows distinct corrugations, and a midrib that is exposed adaxially. The vascular system of the midrib consists of a crescent-shaped ring of collateral bundles. Lateral veins diverge from midrib at ∼90°, are typically simple but occasionally branch at base of the lamina. Vein density is 12–15 per cm. Leaves are hypostomatic with syndetocheilic stomata that are randomly oriented between veins. Internal anatomy consists of an adaxial hypodermis of closely-spaced isodiametric cells, mesophyll that is differentiated into adaxial palisade and abaxial spongy zones, and collateral bundles that show a distinct bundle sheath with bundle sheath extensions. This novel combination of characters represents the diverse bennettitalean genus Nilssoniopteris. Nilssoniopteris corrugata new species is only the second species of the genus for which internal anatomy is preserved. This species increases the known variation of bennettitalean leaf anatomy, and reinforces our appreciation for the global distribution of bennettitalean seed plants during the Mesozoic.