The definition of the Cretaceous shark genus Cretodus Sokolov, 1965 is primarily based on isolated teeth. This genus includes five species. Among these, Cretodus houghtonorum Shimada and Everhart, 2019 is the only species based on a partially preserved skeleton. Here, the taxonomic attribution of a virtually complete skeleton of Cretodus from the Turonian of northeastern Italy is discussed, together with a few specimens from the Turonian of England. One of the latter is investigated through micropaleontological analysis to determine its stratigraphic position. The material is referred to Cretodus crassidens (Dixon, 1850), the diagnosis of which is emended herein. The dentition is tentatively reconstructed, exhibiting strong similarities with congeneric species, although it differs in having strong vertical folds on the main cusp labial face, a mesiodistally broad tooth aspect, weak and well-spaced ‘costulae’ at crown base, and a different dental formula in the number of parasymphyseal and lateral rows. Some tooth malformations are interpreted as feeding-related or senile characters. The Italian specimen suggests that Cretodus crassidens had a wide and laterally expanded mouth and head, a stout body, and attained a gigantic size. Cretodus crassidens was a moderate-speed swimming shark ecologically like the extant tiger shark Galeocerdo cuvier (Péron and Lesueur in Lesueur, 1822). The age estimate from vertebral-band counting suggests that the Italian individual was at least 23 years old and the growth model indicates a longevity of 64 years and a maximum attainable total length of 9–11 m. Cretodus crassidens occurs both in Boreal and Tethyan domains, implying a broad paleobiogeographic distribution and a preference toward offshore settings.

The tiny Ordovician trilobite Oenonella Fortey, 1980 has previously been known only from cranidia and pygidia of its Middle Ordovician type species. Two new species, Oenonella wasisnamei and O. otherfellersorum, from the Darriwilian Table Cove Formation, western Newfoundland, Canada, are known from silicified material that provides new information on the librigena, ventral morphology, and intraspecific variation within the group. The stratigraphic range of the genus is extended downward by an occurrence in the Floian of the Shallow Bay Formation, western Newfoundland. New knowledge of Oenonella confirms its likely phylogenetic relationship with Proscharyia Peng, 1990, known from the Tremadocian of South China. In addition, the overlooked Amechilus Ross, 1951, seems to belong to the same group. Both Oenonella and Proscharyia have in the past been assigned to the aulacopleuride family Scharyiidae Osmólska, 1957. New silicified material effectively rules out this possibility. The broader affinity of the group remains obscure, but together the three genera are assigned to the new family Oenonellidae.

UUID:http://zoobank.org/ee3ce7ed-3d9b-4730-a5cb-cf680df418ec

The last clade-level extinction episode affecting the Phylum Brachiopoda has been long-established in the Early Toarcian Mass Extinction Event (ETMEE) around the Pliensbachian-Toarcian transition, when several rhynchonellide groups became extinct and others underwent a notable renewal in the western Tethys. Among them, Wellerelloidea is a long-ranging superfamily severely affected by this environmental crisis, embodying the subfamily Cirpinae as the last wellerelloids worldwide, prior to their global extinction in the Pb-To transition. The profuse record of Lower Jurassic cirpines in the peri-Iberian paleomargins provides an opportunity to clarify the taxonomy of wellerelloid species in the pre-extinction interval. A new species (Cirpa lucentina) is erected and the revision of the Cirpinae taxa around the ETMEE is carried out. Morphometric analysis and the study of internal structures of the shells support separation of the genera Cirpa and Salgirella, adding new supplementary diagnostic criteria. The biogeographic distribution of this clade in the western Tethys and its evolutionary history in the Early Jurassic reveal a pervasive colonization pattern of both epicontinental and epioceanic habitats. The Mediterranean origin of the last representatives of this group is ascertained, but while diversification of Salgirella took place in epioceanic habitats, speciation of Cirpa is unrelated to biochorema boundaries, even colonizing epicontinental seas until their extinction prior to the hyperwarming event that occurred in the basal Serpentinum Zone. A rhynchonellide morphogroup epitomized by cirpines was resilient to this event in the epicontinental seas. This morphogroup is also recorded after the extinction interval by means of the genus Pseudogibbirhynchia, thus postulating potential pre- and post-extinction phyletic relationships.

UUID: http://zoobank.org/100b06c0-a803-4f6f-b0fa-2d9e2d6678d2

Squat lobsters within Galatheoidea are very diverse with over 1,300 extant species that live in all marine ecosystems, but their fossil record, starting in the Middle Jurassic, consists of only ~200 species. Consequently, much remains to be learned about their biodiversity, phylogeny, and paleobiogeography. We describe five new species (Galatheites sforum n. sp., Kimmeridgian, Late Jurassic, Germany; Vasconilia zapotitlanensis n. sp., Barremian, Early Cretaceous, Mexico; Eomunidopsis texcalaensis n. sp., Barremian, Early Cretaceous, Mexico; Protomunida bennickei n. sp., Danian, Paleocene, Denmark; and Protomunida eurekantha n. sp., Danian, Paleocene, Denmark) and one new genus (Tethysgalathea n. gen., Ypresian, Eocene, Italy). We further reassign Munida cretacea (Albian, Early Cretaceous, Texas, USA) to Galathea?, return Eomunidopsis? cobbani (Campanian, Late Cretaceous, Colorado, USA) to its original genus, report on the second occurrence of Vetoplautus latimarginus Robins et al., 2013 (Tithonian, Late Jurassic, Czech Republic), and reinstate Palaeomunidopsis moutieri (middle Bathonian, Middle Jurassic, France) as the oldest galatheoid known to date. The five new species, all found in limestones containing corals, increase galatheoid diversity in the fossil record by 2.5%. Finally, the common yet hitherto unrecognized Protomunida eurekantha was discovered by making casts of external molds, revealing distinct spines on the posterior margin that are more difficult to see in internal molds and specimens with cuticle due to breakage. Collecting and studying the external molds for galatheoids and other fossil decapods could yield additional cryptic species.

UUID: http://zoobank.org/68a25381-65c6-4773-a4f2-71d9b0a25304

Studies of molecular biology suggest a deep origin of coralline red algae in the Neoproterozoic, but unequivocal representatives have not been found in Precambrian rocks. Such scarcity in the fossil record significantly limits our knowledge regarding the origin and early evolution of this group. Phosphatized, fragmented columnar microfossils from the Zhenba microfossil assemblage at the base of the Ediacaran Dengying Formation, South China are presented. Morphologically they represent a novel taxon characterized by: (1) variable and irregularly shaped cross sections, and (2) discontinuous, nonisopachous laminae transversely stacked inside the columns. Integrated morphological comparisons favor their interpretation as probable erect coralline algae. Anatomically, the Zhenba columns resemble present-day geniculate coralline algae in columnar thalli and stromatolithic tissue construction, although they differ from modern geniculate corallines in lacking highly calcified skeletons and tissue-organ differentiation. These anatomical similarities collectively suggest that the Zhenba columns probably represent stem-group coralline algae. The new finding indicates that early coralline algae could be more diverse than previously thought, and their initial morphological diversification and resultant ecological expansion probably occurred in the middle to late Ediacaran.

Titanopterans are spectacular, giant, predatory insects mainly known from the Triassic, but they are known from a few localities in Central Asia (including European Russia) and Australia. The Nampo Group is a nonmarine sequence, located on the southwestern Korean Peninsula, the age of which has remained controversial, due to lack of proper age-constraining fossils. Here, we report a new titanopteran Magnatitan jongheoni n. gen. n. sp. from the Amisan Formation, Nampo Group. The division of the radius anterior and radius posterior beyond the distal half of the fossil wing is a characteristic of the family Paratitanidae. This is the first discovery of a titanopteran fossil outside of Central Asia and Australia, suggesting a possible circum-Tethys oceanic distribution. Given the possibly widespread distribution of titanopterans, this group might have played a critical role as giant predatory insects in Triassic terrestrial ecology. Because titanopterans have never been found beyond the Triassic-Jurassic boundary, the occurrence of a titanopteran corroborates the Triassic age of the Nampo Group.

UUID: http://zoobank.org/10177029-0044-424f-9816-e3fb057cfe85

A new specimen of the arachnid order Trigonotarbida is described from the Middle Pennsylvanian (lower Desmoinesian) Shelburn Formation of Indiana, which has previously yielded the remains of a phalangiotarbid. Two new trigonotarbid arachnid specimens are also described from the Middle Pennsylvanian (Desmoinesian) Senora Formation of Oklahoma. These are the first trigonotarbid specimens reported from Indiana and Oklahoma. The Indiana trigonotarbid belongs to the Eophrynidae, as indicated by distinct features such as the large tubercles on the dorsal surface of the opisthosoma and two pairs of terminal opisthosomal spines. This specimen is the first arachnid fossil to be imaged using a Multistripe Laser Triangulation scanner. The heavy dorsal tuberculation, lobed and subtriangular carapace, rounded clypeus, lack of terminal opisthosomal spines, and rounded opisthosoma on Oklahoma specimen FMNH PE 56932 indicate it belongs to the genus Aphantomartus, in Aphantomartidae. The other Oklahoma specimen, FMNH PE 56955, possesses opisthosomal tergites that are divided into five plates longitudinally as well as a subquadrate carapace, which identify it as a member of Anthracomartidae; its rounded opisthosomal margin shows it to belong to the genus Anthracomartus.

Acritarch biostratigraphic and δ13C chemostratigraphic data from the Krol A Formation in the Solan area (Lesser Himalaya, northern India) are integrated to aid inter-basinal correlation of early–middle Ediacaran strata. We identified a prominent negative δ13C excursion (likely equivalent to EN2 in the lower Doushantuo Formation in the Yangtze Gorges area of South China), over a dozen species of acanthomorphs (including two new species—Cavaspina tiwariae Xiao n. sp., Dictyotidium grazhdankinii Xiao n. sp.), and numerous other microfossils from an interval in the Krol A Formation. Most microfossil taxa from the Krol A and the underlying Infra-Krol formations are also present in the Doushantuo Formation. Infra-Krol acanthomorphs support a correlation with the earliest Doushantuo biozone: the Appendisphaera grandis-Weissiella grandistella-Tianzhushania spinosa Assemblage Zone. Krol A microfossils indicate a correlation with the second or (more likely, when δ13C data are considered) the third biozone in the lower Doushantuo Formation (i.e., the Tanarium tuberosum-Schizofusa zangwenlongii or Tanarium conoideum-Cavaspina basiconica Assemblage Zone). The association of acanthomorphs with EN2 in the Krol Formation fills a critical gap in South China where chert nodules, and thus acanthomorphs, are rare in the EN2 interval. Like many other Ediacaran acanthomorphs assemblages, Krol A and Doushantuo acanthomorphs are distributed in low paleolatitudes, and they may represent a distinct paleobiogeographic province in east Gondwana. The Indian data affirm the stratigraphic significance of acanthomorphs and δ13C, clarify key issues of lower Ediacaran bio- and chemostratigraphic correlation, and strengthen the basis for the study of Ediacaran eukaryote evolution and paleobiogeography.

UUID: http://zoobank.org/5289fdb2-0e49-4b3b-880f-f5b21acab371.

Records of abnormal fossil arthropods present important insight into how extinct forms responded to traumatic damage and developmental complications. Trilobites, bearing biomineralized dorsal exoskeletons, have arguably the most well-documented record of abnormalities spanning the Cambrian through the end-Permian. As such, new records of malformed, often injured, trilobites are occasionally identified. To further expand the documentation of abnormal specimens, we describe malformed specimens of Lyriaspis sigillum Whitehouse, 1939, Zacanthoides sp. indet., Asaphiscus wheeleri Meek, 1873, Elrathia kingii (Meek, 1870), and Ogygiocarella debuchii (Brongniart, 1822) from lower Paleozoic deposits. In considering these forms, we propose that they illustrate examples of injuries, and that the majority of these injuries reflect failed predation. We also considered the origin of injuries impacting singular segments, suggesting that these could reflect predation, self-induced damage, or intraspecific interactions during soft-shelled stages. Continued examination of lower Paleozoic trilobite injuries will further the understanding of how trilobites functioned as prey and elucidate how disparate trilobite groups recovered from failed attacks.

Ordovician open marine Lagerstätten are relatively rare and widely dispersed, producing a patchy picture of the diversity and biogeography of nonmineralized marine organisms and challenging our understanding of the fate of Cambrian groups. Here, for the first time, we report soft-bodied fossils, including a well-preserved marrellomorph arthropod, fragmentary carapaces, and macroalgae, from the Late Ordovician (Katian) Upper Member of the Kirkfield Formation near Brechin, Ontario. The unmineralized elements and associated exceptionally preserved shelly biota were entombed rapidly in storm deposits that smothered the shallow, carbonate-dominated shelf. The marrellomorph, Tomlinsonus dimitrii n. gen. n. sp., is remarkable for its ornate, curving cephalic spines and pair of hypertrophied appendages, suggesting a slow-moving, benthic lifestyle. Reevaluation of marrellomorph phylogeny using new data favors an arachnomorph affinity, although internal relationships are robust to differing outgroup selection. Clades Marrellida and Acercostraca are recovered, but the monophyly of Marrellomorpha is uncertain. The new taxon is recovered as sister to the Devonian Mimetaster and, as the second-youngest known marrellid, bridges an important gap in the evolution of this clade. More generally, the Brechin biota represents a rare window into Ordovician open marine shelf environments in Laurentia, representing an important point of comparison with contemporaneous Lagerstätten from other paleocontinents, with great potential for further discoveries.

UUID: http://zoobank.org/884589d0-08f7-4398-ab42-1f5d459be9e9

A new enantiornithine, Musivavis amabilis n. gen. n. sp., is reported from the Lower Cretaceous Jehol Biota in western Liaoning, China. The new taxon is similar to the bohaiornithids in the robust subconical teeth, bluntly expanded omal ends of the furcula, caudolaterally oriented lateral trabeculae with triangular distal ends of the sternum, and a robust second pedal digit. Yet it differs from members of Bohaiornithidae in several features recalling other enantiornithine lineages, such as the acuminate rostral ramus of maxilla, the shape of the coracoid lateral margin, the presence of craniolateral processes on the sternum, the proportions of the manual phalanges, and the unspecialized third pedal ungual phalanx. A comprehensive phylogenetic analysis of Mesozoic birds shows that homoplasy significantly affects the reconstruction of enantiornithine relationships. When all phylogenetic characters are considered of equal weight, Musivavis is reconstructed in a lineage related to a radiation of large-bodied enantiornithines including Bohaiornithidae and Pengornithidae. Alternative scenarios based on progressive downweighting of the homoplastic characters support more basal placements of the pengornithids among Enantiornithes, but do not alter the affinity of Musivavis as a member of the “bohaiornithid-grade” group.

UUID: http://zoobank.org/617c7062-21ab-4d33-ae80-4edf5a129683

The fossil record of octocorals from Cenozoic marine strata of western North America is quite limited, and they have not been reported previously from rocks in Washington State, USA. Two late Oligocene specimens from the upper part of the Lincoln Creek Formation in western Washington, referred to Radicipes? sp., are the first fossil record of the family Chrysogorgiidae. The family Isididae is represented by an internode and two holdfasts identified as Isidella sp. collected from the Oligocene Pysht Formation, along with specimens questionably identified as Lepidisis sp., possibly the first fossil record for this genus. Together, these are the first confirmed fossils of the Alcyonacea from north of California in western North America. The axes of sea pens from several late Eocene or early Oligocene localities in the Lincoln Creek Formation in the central part of western Washington, and the Pysht and Makah formations on the north side of the Olympic Peninsula, are the first fossil record for the Pennatulacea from western North America; all are tentatively referred to the genus ‘Graphularia’. Large axes from the Lincoln Creek Formation and Makah Formation are referred to ‘Graphularia’ (?) aff. sasai, because they are similar to the species known only from late Eocene and early Oligocene rocks in Japan.

A non-biomineralized arthropod, Protocaris marshi, was described from the lower Cambrian (Dyeran Series 2, Stage 4) of Parker's Cobble in northwestern Vermont in 1884. It represents the first fossil exhibiting Burgess Shale-type preservation to have been discovered. The locality was presumed to have been worked out and was not collected in a significant way for more than 100 years. Rediscovery of productive layers has yielded soft-bodied and lightly sclerotized taxa new to the locality, including the alga Fuxianospora, a possible priapulid, a radiodont, and a specimen tentatively assigned to Herpetogaster. New specimens of the sponge Leptomitus zitteli, the bivalved arthropod Tuzoia, and the chordate Emmonsaspis cambrensis provide additional information on those taxa, and multiple specimens allow a bivalved arthropod, Vermontcaris montcalmi new genus, new species, to be described. The primary mode of fossil preservation is as carbonaceous compressions. The Parker Quarry Lagerstätte complements the Kinzers Formation of Pennsylvania (also Series 2, Stage 4) in revealing the diversity of soft-bodied taxa on the southern margin of the paleocontinent Laurentia.

UUID: http://zoobank.org/2eb3ae7c-6579-403e-a9ab-654c05af4a1b

Lochriea commutata (Branson and Mehl, 1941), a senior subjective synonym of Lochriea montanaensis Scott, 1942, is the type species of Lochriea Scott, 1942, one of the first conodont genera named using bedding-plane assemblages. Lochriea commutata is both wide- and long-ranging, locally stratigraphically important, and a consistently recognized Carboniferous species, despite its taxonomic journey from Spathognathodus to Gnathodus to Paragnathodus to Lochriea.

Lochriea commutata was, as Lochriea montanaensis, initially reported to contain 22+ elements, the apparatus composition of the genus being subsequently amended to 17+ elements based on Lochriea wellsi Melton and Scott, 1973, which is an untenable hypothesis because the latter was a conodontophage. Restudy of original and new bedding-plane assemblages in the mid 1970s established that the first assemblages studied were fecal, the initial reconstruction incorporated elements of two individuals, and Lochriea commutata possessed a feeding apparatus of 2P1, 2P2, 2M, 2S1, 2S2, 2S3, 2S4, and 1S0 elements. A Lochriea sp. bedding-plane assemblage was subsequently found to have the same element composition, and restudy of type material, available bedding-plane assemblages, and new fused clusters confirms that Lochriea commutata had a 15-element ozarkodinid apparatus.

While species are still assigned to Lochriea using carminiscaphate P1 elements almost exclusively, those assignments must be considered tentative until their apparatuses are determined to be similar to that of L. commutata, and until characteristics of elements other than the P1 element, particularly the makellate M element and the bipennate S3/4 element, are also taken into account.

Lochriea bigsnowyensis Scott, 1942 is reassigned to Cavusgnathus Harris and Hollingsworth, 1933.

A highly diverse fauna of dromioid brachyurans from the Serraduy Formation (lower Eocene) in the western Pyrenees (Huesca, Spain) is described and illustrated. Recorded taxa are Mclaynotopus longispinosus new genus new species, Torodromia elongata n. gen. n. sp., Basidromilites glaessneri n. gen. n. sp., ?Basidromilites sp., Sierradromia gladiator n. gen. n. sp., Kromtitis isabenensis n. sp., and ?Basinotopus sp. Other European outcrops have yielded dromioids in association with specific environments, likely coral and sponge reef and siliciclastic soft bottoms; but the present material constitutes the most diverse dromioid assemblage from the lower Eocene worldwide. These dromioids co-occurred with a rich invertebrate fauna and lived near coral–algal reef mounds. Sedimentological data suggest that most of the fauna accumulated in fore reef settings as a result of storm activity. The present material greatly increases the diversity of known dromioid crabs associated with Eocene reef environments.

UUID: http://zoobank.org/aed8cafa-7c64-4e70-bd45-9f357fc37a28

Correct identification of fossil taxa is immensely important for dating molecular phylogenies and understanding when and how quickly modern biodiversity evolved. Fossils that are available for a clade of interest and can be directly incorporated in the phylogenetic analysis are considered primary sources of time calibration, whereas calibrations inferred from other studies are secondary (Arroyave et al., 2013). Studies of taxonomic groups that lack fossils must either expand their analyses to include fossilized outgroup lineages, use secondary calibrations, or use more problematic primary calibrations, e.g., vicariant geologic events. The use of vicariant geologic events to calibrate phylogenies poses the risk of circular reasoning, because the goal of many such studies is to determine how geologic events have affected diversification. Near et al. (2012) argued that fossil calibrations external to clades of interest, but still within the broader Actinopterygian (ray-finned fishes) tree, could be used as means of calibrating a generalized molecular clock, but internal calibrations are still valuable for refining such inferences (Arroyave et al., 2013).

Sloths were among the most diverse groups of land vertebrates that inhabited the Greater Antilles until their extinction in the middle-late Holocene following the arrival of humans to the islands. Although the fossil record of the group is well known from Quaternary deposits in Cuba, Hispaniola, and Puerto Rico, remains from older units are scarce, limiting our understanding of their evolution and biogeographic history. Here we report the oldest known fossil ground sloth from Hispaniola, represented by an unassociated partial tibia and scapula that are recognized as a single taxon from the late Miocene-early Pliocene of the Dominican Republic. The combination of characters observed on the tibia suggests a close relationship with Megalocnus, otherwise only known from the Pleistocene–Holocene of Cuba. These fossils fill a temporal gap between those previously known from the early Miocene of Cuba and those from Pleistocene–Holocene deposits in the region and provide additional support for a continuous presence of the group in the Greater Antilles since the Oligocene.

Temnospondyl amphibians are common in non-marine Triassic assemblages, including in the Fremouw Formation (Lower to Middle Triassic) of Antarctica. Temnospondyls were among the first tetrapods to be collected from Antarctica, but their record from the lower Fremouw Formation has long been tenuous. One taxon, ‘Austrobrachyops jenseni,’ is represented by a type specimen comprising only a partial pterygoid, which is now thought to belong to a dicynodont. A second taxon, ‘Cryobatrachus kitchingi,’ is represented by a type specimen comprising a nearly complete skull, but the specimen is only exposed ventrally, and uncertainty over its ontogenetic maturity and some aspects of its anatomy has led it to be designated as a nomen dubium by previous workers. Here, we redescribe the holotype of ‘C. kitchingi,’ an undertaking that is augmented by tomographic analysis. Most of the original interpretations and reconstructions cannot be substantiated, and some are clearly erroneous. Although originally classified as a lydekkerinid, the purported lydekkerinid characteristics are shown to be unfounded or no longer diagnostic for the family. We instead identify numerous features shared with highly immature capitosaurs, a large-bodied clade documented in the upper Fremouw Formation of Antarctica and elsewhere in the Lower Triassic. Additionally, we describe a newly collected partial skull from the lower Fremouw Formation that represents a relatively mature, small-bodied individual, which we provisionally refer to Lydekkerinidae; this specimen represents the most confident identification of a lydekkerinid from Antarctica to date.

Gennaeocrinus tariatensis new species is an Emsian (Devonian) monobathrid crinoid described from the Tarvagatay Terrane of Mongolia and part of the Central Asian Orogenic Belt. The Tarvagatay Terrane is an arc terrane that accreted to the southern margin of the Siberian Craton. Gennaeocrinus tariatensis was collected from the Emsian Tariat Formation, a terrigenous sequence of conglomerates, sandstones, and siltstones. Associated faunas include brachiopods, molluscs, and rare tabulate corals. Although Gennaeocrinus is well known from the Emsian–Givetian of North America, this is the first occurrence of the genus outside Laurussia. Mongolia is a large country with many terranes having varied paleogeographic, sedimentological, and tectonic histories; but reports of Paleozoic echinoderms are rare. The crinoid occurrence from the Tariat Formation is from the same age as previously described Emsian crinoids from the Chuluum Formation but differs significantly in sedimentology, paleogeography, and paleolatitude.

UUID: http://zoobank.org/d87cb083-4360-41e5-ac90-1b8ef625a31d