Claraia Bittner, 1901 is a prominent extinct bivalve genus of the Permian-Triassic transition (Newell and Boyd, 1995). Although it first appeared in the Wuchiapingian (Late Permian; Fang Zong-Jie, 2010), its massive proliferation in the immediate wake of the end-Permian mass extinction makes it the archetype of a cosmopolitan and eurytopic disaster species and a hallmark of the base of the Triassic (e.g., Schubert and Bottjer, 1995). Diener (1923, p. 38) fixed “Posidonomya Clarai Emmrich (1844)” as the type species of Claraia by subsequent designation, but spelling and authorship of this species have been controversial. This short contribution aims to clarify these issues.

Borophagus is the terminal genus of the highly diverse and successful subfamily, Borophaginae. Skeletal remains of this bone-crushing canid are most commonly found in transitional or grassland environments across North America between Late Miocene–Middle Pleistocene, but are rare or absent in forested habitats. Here, we describe a humerus from the Gray Fossil Site of Tennessee, which is the first occurrence of this genus in a heavily forested ecosystem. The distinct limb proportions of Borophagus suggest the genus may have been well suited for a closed habitat like the Gray Fossil Site, contrary to where a majority of their fossils have been previously found. This discovery documents the first pre-Pleistocene occurrence of a canid in the Appalachian region of the eastern United States.

The Late Ordovician (late Katian) Tcherskidium fauna consisted of large- and thick-shelled virgianid pentamerid brachiopods characterized by large and ribbed shells of Tcherskidium and Proconchidium and usually associated with Holorhynchus, Deloprosopus, and Eoconchidium. This unique fauna was widely distributed across several tectonic plates, largely confined to the paleoequatorial and especially the northern paleotropical zones, such as northern Laurentia, accretionary terranes of Alaska, Kolyma, Baltica, Siberia, Kazakh and adjacent terranes, and South China. In Laurentia, the eponymous genus Tcherskidium was predominant in regions north of the paleoequator and, in sharp contrast, was absent south of the paleoequator. In this study, Tcherskidium lonei n. sp. and Proconchidium schleyi n. sp. are described from Alaska and North Greenland, respectively, adding new data on the Tcherskidium fauna of the Late Ordovician Northern Hemisphere. Shell gigantism, together with the sharp paleobiogeographic division, suggests that the Late Ordovician (late Katian) Northern Hemisphere had a prevailing warm-water mass, probably due to the lack of large landmass beyond the northern tropics. This was in sharp contrast to the Southern Hemisphere, which was frequently influenced by cold-water invasions from the ice-bearing Gondwana supercontinent centered on the South Pole.

UUID: http://www.zoobank.org/25d9b772-bd7d-4ad6-bfc6-ba02b1567cf3

Lower and middle Cambrian strata of the eastern Mackenzie Mountains, Northwest Territories, Canada, were deposited in a semi-enclosed basin along the eastern flank of the Mackenzie Arch. The Mount Clark Formation is predominantly composed of nearshore sandstone and is overlain by deeper water siltstone, mudstone, and carbonates of the Mount Cap Formation. The contact between these formations is interpreted as a flooding surface. Trilobite biostratigraphy indicates the presence of the traditional upper Olenellus through Glossopleura zones (Cambrian Series 2, Stage 4–Miaolingian, Wuliuan) and suggests the flooding surface is diachronous, spanning the Dyeran-Delamaran boundary. Above the Olenellus Zone, the Amecephalus arrojosensis-Eokochaspis nodosa Zone, the new Aitkenaspis keelensis Zone, the new Albertelloides mischi Zone, and the Glossopleura walcotti Zone are recognized. Whereas the older zones are comparable to those in other areas of Laurentia, the trilobite faunas in the Albertelloides mischi and Glossopleura walcotti zones show a greater abundance of zacanthoidids and dolichometopids. They also have a lower diversity of ptychoparioids and oryctocephalids, and lack agnostoids, eodiscoids, dorypygids, and ogygopsidids. This suggests that zacanthoidids and dolichometopids were able to tolerate conditions that were unfavorable to the other groups, probably related to semi-restricted conditions in the basin. Four endemic species exhibit characteristics that are considered paedomorphic. This developmental process took place in three separate lineages, suggesting that heterochrony was also environmentally provoked.

New taxonomic names are authored by Handkamer and Pratt. New genera are Eobathyuriscus, Sahtuia, Mexicaspidella Aitkenaspis, Dodoella, and Mackenzieaspis. New species are Bolbolenellus dodoensis, Eobathyuriscus mackenziensis, E. macqueeni, Glossopleura youngi, Sahtuia carcajouensis, Aitkenaspis keelensis, Albertelloides eliasi, Dodoella kobayashii, Mackenzieaspis parallelispinosa, and M. divergens.

UUID: http://zoobank.org/a10a2470-853c-4ce8-bf62-7de1d2c99fab.

The diversity of mid-Cretaceous tyrannosauroids is poorly understood. We describe a partial tyrannosauroid femur from the Albian–Cenomanian Wayan Formation of eastern Idaho that helps to fill in an important spatiotemporal gap in the North American record of tyrannosaurs. This specimen, consisting of the proximal half of the bone, is morphologically similar to the femur of Moros intrepidus, a small-bodied tyrannosauroid from the Cenomanian Mussentuchit Member of the Cedar Mountain Formation of Utah, but not referable to this taxon. The Wayan femur lacks an autapomorphy diagnostic for Moros intrepidus, indicating the presence of a previously unrecognized tyrannosauroid taxon in the early Late Cretaceous of Laramidia. Histological results indicate that, at the time of death, this individual was at least five years old, skeletally immature, and undergoing growth at a moderate rate. The addition of this tyrannosauroid to the Wayan-Vaughn Assemblage provides additional evidence for the widespread distribution of various tyrannosauroid taxa in Laramidia during the early Late Cretaceous.

Two rare, phosphatized, tubular microfossils of uncertain affinity, probably algal, are described from the Portfjeld biota (Ediacaran) of North Greenland. Portfjeldia aestatis n. gen. n. sp. preserves two tubules, one of which branches, within an annulated outer sheath. Its morphology can be compared to that of the much larger Ramitubus from the Weng'an biota of South China. An unnamed long, parallel-sided tubule occupied the postmortal cavity formed within diagenetically mineralized specimens of the cyanobacterium Jiangispirellus.

The Cambrian successions at the Chihuarruita Hill outcrop, Sonora, Mexico, have yielded two successive linguliform brachiopod assemblages that are transitional between Cambrian Stage 4 and the newly recognized global Wuliuan Stage. The lowermost assemblage includes Dictyonina sp., Paterina sp., Eothele sp., Hadrotreta rara? (Cooper), and Linnarssonia arellanoi? (Cooper), coming from the upper part of the Buelna Formation. The younger, recently named El Gavilán Formation contains a more diverse linguliform brachiopod assemblage, including Acrothele concava Cooper, Batenevotreta? mexicana n. sp., Dictyonina minutipuncta Cooper, Eothele sp., Eoobolus sp., Hadrotreta rara? (Cooper), Linnarssonia arellanoi? (Cooper), Micromitra sp., Paterina sp., and Prototreta sp. The El Gavilán Formation contains a diverse trilobite fauna suggesting Delamaran age in terms of the Laurentian regional stratigraphical scheme. The base of the global Wuliuan Stage and Miaolingian Series is defined by the first occurrence of Oryctocephalus indicus; in the absence of the index species, the base should be provisionally placed at the base of the El Gavilán Formation. The Wuliuan age of the brachiopod assemblage recovered from the El Gavilán Formation is supported by the occurrence of Acrothele in the Cambrian biostratigraphical succession of Himalaya, where the genus makes its first appearance in the Kaotaia prachina Zone. In addition, the co-occurrences of Acrothele and Eothele can be taken as an indication of the Wuliuan age of the fauna. A new biogeographic analysis confirms that the Eothele Fauna first appeared at the end of Cambrian Stage 4, as a result of increased faunal migration within the southern tropical latitudes directed from Australasian Gondwana to Laurentia.

UUID: http://zoobank.org/6598f51f-cb07-4df3-bd1f-025a13e64edf

Two previously known species of stromatoporoids are reported from Nevada: Stromatoporella perannulata, from the Bartine Member of the McColley Canyon Formation (middle Emsian); and Stictostroma moosense, from the Oxyoke Canyon Sandstone (uppermost Emsian). A new species, Syringodictyon nevadense n. sp., is described from the Coils Creek Member of the McColley Canyon Formation (upper Emsian). Stromatoporella perannulata also occurs in Emsian-age strata on Ellesmere Island, arctic Canada, and in strata of Emsian and/or Eifelian age in Ontario, New York, Ohio, and Kentucky. Outside Nevada, Syringodictyon is confined to the Emsian of Ellesmere Island, and Emsian/Eifelian of Ontario and New York. Stictostroma moosense is known from only the Emsian/Eifelian of Ontario.

It is concluded that the three Nevada specimens are Emsian in age. This implies that in other localities where two of the species, S. perannulata and S. moosense, occur in strata where the placement of the Emsian-Eifelian boundary is in question, it might be higher than previously thought. The presence of the two species, plus Syringodictyon, in both the Old World Realm (Nevada, arctic Canada) and the Eastern Americas Realm (Ontario, New York, Ohio, Kentucky), infers a selective marine connection between the two realms that was not available to other taxa. The breach in the inter-realm barrier most likely occurred as a shallow seaway across the Canadian Shield.

UUID: http://zoobank.org/e73023c6-88ca-4b4d-9b01-f74a75b99c43

The Nasep and Huns members of the Urusis Formation (Nama Group), southern Namibia, preserve some of the most diverse trace-fossil assemblages known from the latest Ediacaran worldwide, including potentially the world's oldest “complex” vertical sediment-penetrating burrows. These sediments record relatively diverse communities of bilaterian metazoans existing before the base of the Cambrian and an increase in the intensity of metazoan ecosystem engineering behaviors that could eventually produce profound changes in the character of the Phanerozoic sedimentary record (the “agronomic revolution”). Despite this, relatively little about this trace-fossil assemblage is known. We explore the Nasep–Huns transition at two localities in the Witputs sub-basin and describe the trace- and body-fossil diversity present in these horizons alongside a paleoenvironmental reconstruction. We document eight unique ichnotaxa from these localities, including well-preserved “probes” potentially left by priapulids. We also report the first occurrence of Corumbella from Namibia, helping to establish a biostratigraphic link between Namibia, Brazil, Paraguay, Iran, and the southwestern United States. Last, we find that several ichnotaxa, in particular small treptichnids, appear to be preferentially preserved on the bases of gutter casts, hinting at the potential existence of an unusual late Ediacaran preservational window with possible implications for timing the first appearance of key bilaterian behaviors.

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