The first report of the Hirnantia high-latitude peri-Gondwanan Fauna from Portugal (Upper Ordovician, Ribeira do Braçal Formation) is presented here. The described macroassemblages are fairly diverse containing fossils of brachiopods, trilobites, echinoderms, machaeridians, and ostracodes. Among the brachiopods, the most abundant is Mirorthis mira. Plectothyrella cf. P. libyca, Paromalomena cf. P. polonica, Plectoglossa? sp., and a small indeterminate discinoid are also present. The trilobites are represented by abundant sclerites of Mucronaspis cf. M. mucronata, and an isolated cranidium and pygidium assigned to Flexicalymene. The occurrence of Mucronaspis and Flexicalymene represents the first record of these genera in Portugal. Echinoderms are dominant in the basal bed of the formation; the columnal plates tentatively ascribed to morphogenus Pentagonocyclicus are the most abundant, followed by the echinosphaeritids. Abundant disarticulated machaeridian plates, of the genus Plumulites, associated with trilobites are present in one of the localities. Ostracodes were found in one single locality and have been assigned tentatively to the genus Herrigia. Ramose and massive bryozoans also occur in the assemblage. This new macrofossil assemblage supports the assignment of an Hirnantian age for the Ribeira do Braçal Formation. Most of the brachiopod species and the dalmanitid Mucronaspis are commonly present in Hirnantian deposits globally, but the presence in the assemblage of a brachiopod close to Plectothyrella libyca, a cold-water species, previously reported only from the Hirnantian of Libya and Morocco, is noticeable. This strengthens the case for a high latitudinal setting of the present-day territory of the Portuguese Central Iberian Zone during the Late Ordovician.

Exceptional sub-micrometer details of shell microstructure are preserved in phosphatic micro-steinkerns representing several phyla from shell beds of the Upper Ordovician of the Cincinnati Arch region, USA. These fossils provide the most detailed record of Ordovician mollusk shell microstructures, as well as exceptional details on the earliest cases of undisputed nacre. The trend towards nacre in the Mollusca is one aspect of the surge in escalation between mollusks and their predators during the Great Ordovician Biodiversification Event.

Permian faunal affinity in the Lhasa Block plays a critical role in reconstructing its paleogeographic evolution. Cisuralian and Guadalupian faunas have been described from the Lhasa Block, but very few Lopingian (late Permian) brachiopods have been reported so far. In this paper, a new diverse brachiopod fauna consisting of 17 species of 17 genera and an unidentifiable Orthotetoidea is described from the uppermost part of the Xiala Formation at the Aduogabu section in the central part of the Lhasa Block. The age of this fauna can be assigned to the Changhsingian (late Lopingian) as indicated by the associated foraminifers Colaniella parva (Colani, 1924) and Reichelina pulchra Miklukho-Maklay, 1954. Characteristic brachiopods include Spinomarginifera chengyaoyenensis Huang, 1932, Haydenella wenganensis (Huang, 1932), and Araxathyris cf. dilatatus Shen, He, and Zhu, 1992. They also generally suggest a Changhsingian age. Paleobiogeographically, this fauna is uniformly composed of typical Tethyan elements represented by Spinomarginifera Huang, 1932 and Haydenella Reed, 1944, and some cosmopolitan elements, but no typical cold-water taxa of Gondwanan affinity. This is in contrast to the contemporaneous brachiopod faunas from the Tethys Himalayan region that are characterized by typical cold-water taxa of Gondwanan affinity, e.g., Costiferina indica (Waagen, 1884), Retimarginifera xizangensis Shen et al., 2000, Neospirifer (Quadrospina) tibetensis Ding, 1962. Thus, it is strongly indicative that the Lhasa Block had drifted into a relatively warm-water regime during the Changhsingian. An analysis of the paleobiogeographic change of brachiopods in the Lhasa Block throughout the entire Permian further suggests that the Lhasa Block probably had rifted away from the northern peri-Gondwanan margin between the latest Cisuralian and middle Guadalupian, that is, the Neotethys Ocean had opened before middle Guadalupian.

Bed-by-bed sampling of the lower portion of the Daye Formation at Gujiao, Guizhou Province, South China, yielded new Griesbachian–Dienerian (Induan, Early Triassic) ammonoid faunas showing a new regional Induan ammonoid succession. This biostratigraphic scheme includes in chronological order the late Griesbachian Ophiceras medium and Jieshaniceras guizhouense beds, and the middle Dienerian Ambites radiatus bed. The latter is recognized for the first time as a separate biozone in South China. Eight genera and 13 species are identified, including one new species, Mullericeras gujiaoense n. sp. The new data show that a relatively high level of ammonoid taxonomic richness occurred rather rapidly after the Permian/Triassic mass extinction in the late Griesbachian, echoing similar observations in other basins, such as in the Northern Indian Margin.

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Seven species belonging to the gastropod family Volutidae are reported for the first time from Kutch, Gujarat, India. They are Prestrombus aff. Prestrombus rockei Cox, 1931, Indovoluta humberti (d'Archiac and Haime, 1854), Indovoluta multidentata (d'Archiac and Haime, 1854), Involuta daviesi Cox, 1931, Involuta coxi new species, Athleta (Volutocorbis) harnaiensis Cox, 1931, and Lyria cf. Lyria punjabensis Eames, 1952. Indovolutinae new subfamily, constituted of the Paleogene genera Prestrombus Douvillé, 1929, Indovoluta Eames, 1956, Involuta Cox, 1931, and Lyrischapa Aldrich, 1911, and the Cretaceous genus Gosavia Stoliczka, 1865, is proposed. These forms have elaborate development of columellar plaits. All of these genera evolved in the western part of the Indian subcontinent. They, except Lyrischapa, also largely remained restricted to this area. Lyrischapa flourished in the Americas after possibly migrating through the southern margin of the relict Tethys Ocean and crossing the Atlantic Ocean. It is argued that the geographic and temporal restriction of this new subfamily was due to lecithotrophic larval development.

UUID: http://zoobank.org/14bc056f-1d2e-4674-b624-9eb8e856a1f0

The Moscow Syneclise on the East European Platform is an important area for the study of the continental biota of late Permian to Early Triassic age in continuous sections. This study attempts a taxonomic description of the late Permian conchostracan fauna of this area. The rich, new material was collected, bed by bed, during geological and paleontological excavations of lacustrine and fluvial deposits of the Obnora Formation and Vokhma Formation of the late Permian Zhukovian Regional Stage near the towns of Vyazniki and Gorokhovets. The conchostracan fauna of the Zhukovian Regional Stage consists predominantly of Pseudestheria and less frequently of Palaeolimnadiopsis. In the earliest Triassic Vokhmian Regional Stage, a more diverse fauna including Euestheria, Magniestheria, Cornia, Palaeolimnadiopsis, and Rossolimnadiopsis was already recorded. The preliminary taxonomic determination of the pseudestheriids from the Zhukovian Regional Stage is intended to serve as a prerequisite for future studies of late Permian conchostracan biostratigraphy on the regional to interregional scale.

Major transitions in trilobite ontogeny have historically been defined based on the number and distribution of trunk segments, and articulation between the trunk and cephalon. This study documents additional morphological change across the meraspid-holaspid transition on the Ordovician phacopid trilobite Calyptaulax strasburgensis. An extensive dataset of silicified cranidia and pygidia collected from the mid-Ordovician Edinburg Formation of Virginia was subjected to a series of multivariate analyses, with a primary focus on the intersections and termini of furrows. Multivariate regression of partial warp scores demonstrates statistically significant change in allometric growth patterns over the course of development. These changes are concentrated in earlier instars, but are coincident in cranidia and pygidia. This sharp decrease in the rate of allometry, present in both tagmata, is expressed as significant breakpoints derived from a segmented regression, with the largest portion of allometric change found in the pre-breakpoint individuals. The term holeidos is proposed to describe the completion of form during trilobite development, independent of the completion of the thorax. The most dramatic change in shape during this period of ontogeny includes lateral glabellar expansion through deflection of the axial and palpebral furrows, possibly reflecting a change in the feeding habit during later development. Other morphological changes include the development of a more angular appearance to the anterior portion of the glabella, and anterior migration of the pygidial anterior margin. The appearance of these growth patterns in Calyptaulax extends the temporal range of these changes, some of which have only been documented in Devonian phacopids.

The biofacies of the Lower Palmatolepis rhenana Biozone to Palmatolepis triangularis Biozone in the Mae Sariang section, northwestern Thailand, are marked by alternations of Palmatolepis-dominated biofacies and Polygnathus-dominated biofacies related to fluctuations in seawater depth. Fine-grained limestone accumulated through the Lower Palmatolepis rhenana Biozone, Upper Palmatolepis rhenana Biozone, Palmatolepis linguiformis Biozone, Palmatolepis subperlobata Biozone, and Palmatolepis triangularis Biozone. A regression in the Upper rhenana Zone was followed by a recovery transgression that extended up through the linguiformis Zone. Conodont faunas increased until near the end of the linguiformis Zone, but in the overlying subperlobata Zone and triangularis Zone, conodont numbers dropped and most conodont species disappeared. It is possible the event coincides with a glacially forced regression, but there is no evidence of this in the section apart from a positive spike in δ13C. Another possible cause of the global marine extinction event is toxic levels of metals resulting from widespread volcanism. New taxa in this paper are Palmatolepis chaemensis new species, Palmatolepis thamensis new species, and Polygnathus tenellus surinensis new subspecies.

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Gymnolaemate bryozoans are common encrusters on bivalve shells from the early to middle Albian parts of the Glen Rose and Walnut formations of southcentral and northcentral Texas. Here, we report for the first time the presence of seven gymnolaemate bryozoans, all of which represent new species. They include the bioimmured ctenostome Simplicidium jontoddi n. sp., and the cheilostomes Rhammatopora glenrosa n. sp., Iyarispora ikaanakiteeh n. gen. n. sp., Iyarispora chiass n. gen. n. sp., Charixa bispinata n. sp., Charixa sexspinata n. sp., and Charixa emanuelae n. sp. The Glen Rose bryozoans slightly antedate the commencement of an explosive bryozoan radiation and the first appearance of neocheilostomes in the late Albian. Although the diversity of cheilostomes in the Glen Rose and Walnut formations is similar to that of cyclostomes, cheilostomes are more abundant and produced larger colonies. These formations therefore yield the oldest known bryozoan assemblage dominated in terms of biomass by cheilostomes. The genus concept of Charixa is discussed and amended.

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Naticid taxonomy is in a state of flux owing to non-descript shell morphology and frequent convergence. Inadequate preservation of naticid body fossils has further complicated the matter in determining the true affinity and the exact time of origin of the clade. As a result, a plethora of classificatory schemes of naticid phylogeny and times of origin has been proposed. In many previous studies, true naticid affinities of fossils have been sought based on single or a few morphological characters, which are susceptible to poor preservation. In the present paper, we have attempted a holistic reappraisal of naticid taxonomy based on an extensive database of shell morphological characters and identified many distinct family- and subfamily-specific characters that survived fossilization. This approach has enabled us to identify three new naticid species from the Late Jurassic horizons of Kutch, India, thus extending back the time of origin of the family Naticidae by 30 Ma.

Analysis of character matrix data reveals that the present species—Gyrodes mahalanobisi new species, Euspira jhuraensis new species, and Euspira lakhaparensis new species—belong to two subfamilies, Gyrodinae and Polinicinae. The occurrence of typical naticid drill holes on various coeval gastropod and bivalve taxa along with these body fossils provides strong supporting evidence for the naticid affinity of these forms.

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Gastropods of the southwestern Atlantic genus Antistreptus Dall, 1902 from extant and Neogene deposits are reviewed. Fossil specimens come from the Punta Entrada Member of the Monte León Formation (50°21′25.4″S, 68°53′05.9″W). Extant samples are from museum collections and two expeditions on board the R/V “Puerto Deseado” to Burdwood Bank (54°13.934′S, 66°30.997′W) and surroundings. Dissection of soft parts and study of the type material of A. magellanicus Dall, 1902, Euthria (Glypteuthria) contraria Strebel, 1908, and A. rolani Castellanos, 1986 reveal that the latter two nominal species are synonymous. Neogene material assigned to the same genus could not be distinguished as a different species. According to the stratigraphic occurrence of the fossil material, the life-span of the genus Antistreptus Dall, 1902 and the species A. magellanicus Dall, 1902 is ~22 Myr, similar to that of the bivalve Cyclochlamys argentina Pastorino and Griffin, 2018.

In midcontinent North America, the Fox Hills Formation (Upper Cretaceous, upper Maastrichtian) preserves the last marine faunas in the central Western Interior Seaway (WIS). Neritoptyx hogansoni new species, a small littoral snail, exhibited allometric change from smooth to corded ornament and rounded to shouldered shape during growth. Specimens preserve a zig-zag pigment pattern that changes to an axial pattern during growth. Neritoptyx hogansoni new species was preyed on by decapod crustaceans, and spent shells were occupied by pagurid crabs. Dead mollusk shells, particularly those of Crassostrea subtrigonalis (Evans and Shumard, 1857), provided a hard substrate to which they adhered on the Fox Hills tidal flats. This new neritimorph gastropod establishes a paleogeographic and chronostratigraphic proxy for intertidal conditions on the Dakota Isthmus during the late Maastrichtian. Presence of a neritid extends the marine tropical/temperate boundary in the WIS northward to ~44° late Maastrichtian paleolatitude. Late Maastrichtian closure of the isthmus subsequently altered marine heat transfer by interrupting northward flow of tropical currents from the Gulf Coast by as much as 1 to 1.5 million years before the Cretaceous ended.

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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 new fossil spider is described from the early Eocene (Ypresian) Palana Formation (54 to 57 Ma) at the Gurha opencast lignite mine, near Bikaner, western Rajasthan, India. It is the first report of a nonamber fossil spider from India. The fossil is referred to the modern genus Nephila Leach, 1815, but with hesitation because, while its habitus is similar to that genus, it lacks the behavioral synapomorphies that distinguish the genus.

Since the genus Retrotapes was erected, some authors have favored or opposed its validity, or argued about the assignment of the extant species R. exalbidus and R. lenticularis to Retrotapes. Some authors synonymized Retrotapes with the Miocene genus Frigichione, and others with the extant genus Eurhomalea to which most of the species that belong to Retrotapes were previously assigned. In the present contribution, a phylogenetic analysis of the genus is performed to test these controversies. In addition, a systematic revision of the Chilean species of the genus is performed to complete the analysis of Retrotapes taxa from Patagonia and Antarctica started by previous authors. This study demonstrates that Retrotapes is a monophyletic genus, which is not closely related to Frigichione or Eurhomalea. Instead, Retrotapes is closely related to some Austral taxa from Kerguelen Island (Paleomarcia), New Zealand (Atamarcia), and Australia (Katelysia), a relationship previously unknown. Besides, the extant species R. lenticularis and R. exalbidus belong to Retrotapes and were recovered as part of a clade closely related to the type species of the genus, R. ninfasiensis (Miocene, Patagonia). Retrotapes is reported in Chile beginning in the late Eocene, where it was represented by R. difficilis n. comb., which is a taxon that resembles some Eocene species of the same genus from Antarctica. In the late Oligocene–early Miocene, it was represented by R. navidadis and later in the Pliocene by three species: the fossil R. fuenzalidae and the two extant ones.

Abundant platform-bearing gondolellid conodonts, including Scythogondolella mosheri (Kozur and Mostler), Sc. phryna Orchard and Zonneveld, and Sc. cf. milleri (Müller), have been discovered from the Yiwagou Section of Tewo, together with Novispathodus waageni waageni (Sweet) and Nv. w. eowaageni Zhao and Orchard. This is the first report of Smithian platform-bearing gondolellids from the Paleo-Tethys region. In addition, Eurygnathodus costatus Staesche, E. hamadai (Koike), Parafurnishius xuanhanensis Yang et al., and the genera Pachycladina Staesche, Parachirognathus Clark, and Hadrodontina Staesche have also been recovered from Dienerian to Smithian strata at Yiwagou Section. Three conodont zones are established, in ascending order: Eurygnathodus costatus-E. hamadai Assemblage Zone, Novispathodus waageni-Scythogondolella mosheri Assemblage Zone, and the Pachycladina-Parachirognathus Assemblage Zone.

The platform-bearing gondolellids were globally distributed just after the end-Permian mass extinction, but the formerly abundant Clarkina Kozur disappeared in the late Griesbachian. Platform-bearing gondolellids dramatically decreased to a minimum of diversity and extent in the Dienerian before recovering in the Smithian. Scythogondolella Kozur, probably a thermophilic and eurythermic genus, lived in all latitudes at this time whereas other genera did not cope with Smithian high temperatures and so became restricted to the high-latitude regions. However, the maximum temperature in the late Smithian likely caused the extinction of almost all platform-bearing gondolellids. Finally, the group returned to equatorial regions and achieved global distribution again in the cooler conditions of the late Spathian. We conclude that temperature (and to a lesser extent oxygen levels) exerted a strong control on the geographical distribution and evolution of platform-bearing gondolellids in the Early Triassic.

Sertulaster keslingi new genus new species (Palaeasteridae) and Delicaster hotchkissi new species (Permasteridae) are asteroid echinoderms described, respectively, from the Ordovician and Carboniferous of eastern North America. The new genus and species help to document diversity within taxa of lower rank. S. keslingi is similar to the Early Ordovician Eriaster Blake and Guensburg, 2005 but exhibits less differentiation of the skeletal elements from beyond the ambulacral column, that of the so-called extraxial skeleton, whereas the comparatively robust construction of Delicaster hotchkissi clearly departs from that of the type species, D. enigmaticus (Kesling, 1967). Small sample sizes and incomplete exposure of available specimens illustrate ambiguities typically encountered in the study of fossil asteroids.

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Cretaceous aquatic ecosystems were amazingly diverse, containing most clades of extant aquatic vertebrates as well as an array of sharks and rays not present today. Here we report on the chondrichthyan fauna from the late Maastrichtian site that yielded the Tyrannosaurus rex skeleton FMNH PF 2081 (“SUE”). Significant among the recovered fauna is an unidentified species of carcharhinid shark that adds to the fossil record of this family in the Cretaceous, aligning with estimates from molecular evidence of clade originations. Additionally, a new orectolobiform shark, here named Galagadon nordquistae n. gen. n. sp., is diagnosed on the basis on several autapomorphies from over two-dozen teeth. Common chondrichthyan species found at the “SUE” locality include Lonchidion selachos and Myledaphus pustulosus. Two phylogenetic analyses (Maximum Parsimony and Bayesian Inference) based on twelve original dental character traits combined with 136 morphological traits from a prior study of 28 fossil and extant taxa, posited Galagadon n. gen. in two distinct positions: as part of a clade inclusive of the fossil species Cretorectolobus olsoni and Cederstroemia triangulata plus extant orectolobids from the Maximum Parsimony analysis; and as the sister taxon to all extant hemiscyllids from the Bayesian Inference. Model-based biogeographical reconstructions based on both optimal trees suggest rapid island hopping-style dispersal from the Western Pacific to the Western Interior Seaway of North America where Galagadon n. gen. lived. Alternatively, the next preferred model posits a broader, near-global distribution of Orectolobiformes with Galagadon n. gen. dispersing into its geographic position from this large ancestral range.

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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.

Knowledge on Early Jurassic marine fossil invertebrates from Argentina is very uneven. Particularly, faunas from Chubut Province received less attention and were thought to be poorer than those from the Neuquén Basin. Nevertheless, an updated revision of bivalves shows that some groups, such as the Protobranchia, were relatively more diverse in Chubut than in Neuquén during late Pliensbachian–early Toarcian times. Only four species are known from the southern areas of the Neuquén Basin, while seven species (three of them new) are here described from Chubut, belonging to the families Nuculidae, Nuculanidae, Polidevciidae, and Malletiidae. The new species are: Palaeonucula feruglioi n. sp., Ryderia tehuelchana n. sp., and Phaenodesmia? piatnitzkyi n. sp. The material is well preserved and allows a detailed analysis of their hinge regions and other internal characters. The presence in Chubut of Palaeoneilo? patagonidica (Leanza) is confirmed, which, along with Praesaccella ovum (Sowerby), are the only two species in common with the Neuquén Basin. The new species Ryderia tehuelchana, belonging to a genus that had a wide global distribution between Rhaetian and Toarcian times, but which was known from South America only for upper Triassic deposits, is of special paleobiogeographic interest. These bivalves are restricted to normal marine environments, and due to their detritivorous feeding habits they only live in organic-rich bottoms as very active shallow burrowers.

UUID: http://zoobank.org/41225cf2-b7de-4ff0-ad20-ce0d738799a9