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Metoposaurids are some of the most commonly occurring tetrapods in non-marine Upper Triassic sediments in the northern hemisphere of Pangea. Since the first description of a metoposaurid in 1842, nearly two dozen species have been named, but many of these have been regarded with increasing skepticism by modern workers because of minor differences used to validate novel species and sometimes novel genera. More recent comprehensive descriptions and evaluations of intraspecific variation from several presumed monospecific bonebeds of metoposaurids have prompted reevaluation of holotypes due to variation in proposed apomorphies. Four metoposaurid species were named from the Popo Agie Formation exposures of Wyoming, U.S.A., but at present, only a single species, Anaschisma browni, is considered valid following a recent redescription of two of these taxa (An. browni and An. brachygnatha). The other two taxa, Borborophagus wyomingensis and Koskinonodon princeps, have not been redescribed since their original description in 1929. A redescription of the holotypes of these two taxa is presented here to assess their historic synonymy with An. browni and to provide a detailed, updated record of the Popo Agie Formation metoposaurids in light of a historic relative lack of attention compared with other North American deposits. Our confirmation of the conspecificity of all four Popo Agie Formation metoposaurids permits a detailed discussion of potential ontogenetic variation in the Popo Agie Formation metoposaurids and latitudinal variability in An. browni.
Recently collected temnospondyl fossils from the Cisuralian Pedra de Fogo Formation (north-eastern Brazil) indicate a diverse assemblage of aquatic tetrapods, including the dvinosaurs Timonya anneae and Procuhy nazariensis. Here we present revised diagnoses for these species and detailed descriptions of their holotypes. Timonya anneae is distinguished from all other dvinosaurs by several cranial characters including: combined width of both parietals less than interorbital width; presence of a groove-like internal carotid artery foramen; and presence of an ossified opisthotic. In the mandible, T. anneae presents two parasymphyseal fossae on each side of the mandibular symphysis to accommodate palatal fangs and a well-developed postglenoid area. Procuhy nazariensis, mostly preserved as a mold of the skull table and mandible, is diagnosed by the presence of the anteriormost extension of the squamosal posterior to parietal midlength; pineal foramen posterior to the midlength of the parietal; supratemporal exposed on the posterior border of the skull table; and presence of postglenoid process of the surangular separated from the retroarticular process of the articular by the mandibular sulcus. A new inclusive phylogeny of Temnospondyli indicates that Dvinosauria consists of the Trimerorhachidae (including Procuhy as the sister-taxon of Trimerorhachis) and the ‘short-snouted’ dvinosaurs, with Timonya as an early-diverging representative of the latter clade. The Pedra de Fogo dvinosaurs show close relationships with Cisuralian taxa from the North American southwest, reinforcing close paleogeographic connections between these regions in the late Paleozoic, but represent endemic taxa, corroborating the pattern suggested by the plant fossil record.
Trematosaurids were globally distributed Early Triassic temnospondyl amphibians characterized by elongate ‘crocodile-like’ skulls. Some of the most famous trematosaurid fossils were discovered on the island of Spitsbergen in the Arctic Svalbard archipelago. Among these, the short-snouted trematosaurine, Tertrema acuta, is one of the few taxa represented by virtually complete cranial remains. Unusually, however, the type specimens comprise only natural molds that were historically used to reconstruct three-dimensional casts. Here, we re-assess these restorations using the original impressions to phylogenetically analyze and re-diagnose the taxon. Unexpectedly, our first-hand scores differ markedly from previous literature-sourced interpretations and yield conflicting tree topologies that nest T. acuta with long-snouted lonchorhynchines, thus destabilizing the long-favored sub-division of trematosaurids based on their skull shape. We attribute this result to character state conflict and suggest that the traditional classification of trematosaurids may mask more complex evolutionary relationships, as well as possible trophic partitioning, and eco-morphological plasticity.
The fossil record of temnospondyl amphibians in the immediate wake of the Permo-Triassic mass extinction captures extensive taxic and ecological diversity, with most records known from high paleolatitudinal settings. In southern Pangea, the most substantial records come from South Africa and Australia, with a total of over 20 taxa presently recognized. Temnospondyls have also been known from correlated horizons in the lower Fremouw Formation of Antarctica since the late 1960s, but these records are mostly fragmentary, thereby limiting taxonomic resolution to the family level and subsequent biostratigraphic correlations and comparisons between high-latitude basins. Here we report substantial new material of the amphibamiform Micropholis stowi, a relic dissorophoid previously known only from the Katberg Formation (Lystrosaurus declivis Assemblage Zone) of South Africa, from the lower Fremouw Formation. The exceptional preservation of the recently recovered material permits not only confident taxonomic referral but also tentative association of several individuals to the broad-headed morph of the taxon. The recognition of M. stowi in Antarctica represents only the fourth geographic occurrence of a dissorophoid from southern Pangea and supports the hypothesis that high-latitude environments served as refugia for temnospondyls during the mass extinction. In the case of M. stowi, such refugia permitted the persistence of a predominantly Permo-Carboniferous clade, and the Antarctic records discussed here further hint at a poorly sampled cryptic distribution, both of amphibamiforms in southern Pangea and of small-bodied temnospondyls in early Mesozoic deposits.
Since 1990, several localities within the Keuper (upper Middle to Upper Triassic) strata in southern Poland have yielded remains of numerous terrestrial vertebrate species. Here we report a new Upper Triassic vertebrate assemblage from the rediscovered Kocury locality. An incomplete theropod dinosaur fibula named Velocipes guerichi described in 1932 was found there. The site was then forgotten and not explored until our excavations began in 2012, that yielded material of a lungfish, a proterochersid turtle, and a new typothoracin aetosaur Kocurypelta silvestris gen. et sp. nov. The new taxon is characterized by autapomorphies of the maxilla: an elongated edentulous posterior portion longer than 80% of the posterior maxillary process, a short medial shelf restricted to the posterior portion of the bone, an anteriorly unroofed maxillary accessory cavity, and lack of a distinct groove for choanal recess on the anteromedial surface of the bone. These new finds improve our knowledge on the vertebrate diversity of the Germanic Basin in the Late Triassic, evidencing the presence of yet unrecognized taxa. Additionally, the partial cranial aetosaur material emphasizes the issues with the aetosaurian taxonomy that is focused mostly on the osteoderm morphology.
North American soft-shelled turtles, including trionychines and plastomenids, are incredibly abundant in latest Cretaceous through earliest Paleocene sediments. Here we describe a new species of plastomenid turtle, Plastomenus joycei, based on a nearly complete early Danian skeleton from the Denver Formation in the Denver Basin, Colorado. Plastomenus joycei is differentiated from all other plastomenid turtles based on the presence of large eighth costals that are much longer than wide, sinusoidal raised ridges on the carapace, flat posterior edge of the carapace, spike-like epiplastra that lack callosities, a broad entoplastron that lacks a callosity, hyoplastra with two lateral processes, presence of metaplastically ossified hyoplastral shoulders (i.e., anteriorly protruding lappets), and a broad midline contact between the hypo- and xiphiplastra. Plastomenus joycei broadly resembles the Cretaceous Gilmoremys spp. and the Eocene Plastomenus thomasii and exhibits intermediate morphology between the two, most notably in the degree of ossification of the plastron. The increase in plastral ossification, as well as a decrease in overall size and an increase in the doming of the shell, co-occurs with the Cretaceous–Paleogene mass extinction and these morphological changes may be in response to an increase in mammalian predators during the early Paleogene. Plastomenus joycei is most commonly found in riverine sandstone sediments and is hypothesized to be a riverine turtle.
Thunnosaurian ichthyosaurs were one of the most successful lineages of Mesozoic tetrapods in terms of adaptation to a pelagic lifestyle. Among them, the ophthalmosaurids are of particular interest. Their fossils document an early widespread distribution, including high northern and southern latitudes soon after they appear at the Aalenian–Bajocian boundary, becoming almost the only surviving lineage of ichthyosaurs for approximately 76 million years until their extinction at the end of the Cenomanian (Late Cretaceous). Evolutionary innovations that could have been involved in their remarkable evolutionary success are still poorly understood. Two regions of the skeleton, involved in two vital functions – breathing and swimming – depict notable variation among ophthalmosaurids: the narial region and the proximal forefin configuration (i.e., stylopodium-zeugopodium-mesopodium pattern). Here, we describe Catutosaurus gaspariniae gen. et sp. nov., a new Tithonian (Late Jurassic) ophthalmosaurid from the northwest of Patagonia, Argentina. The new taxon depicts a peculiar pattern of the narial opening and forefin. Catutosaurus has an ‘ophthalmosaurine-like’ skull with reduced cheek, triangular squamosal, slender and delicate snout and rounded tooth roots; and ‘platypterygiine-like’ forefin composed by the typical polygonal and tightly packed elements and a broad articulation between the stylopodium and zeugopodial row. Phylogenetic analysis retrieves Catutosaurus nested within basal ophthalmosaurids, at the base of a large clade named here as Panplatypterygiine. New information provided by Catutosaurus suggests that changes in the narial region and complexity of the stylopodium–zeugopodium articulation occurred independently among ophthalmosaurids and not in a stepwise manner along with the evolution of the clade.
Panzhousaurus rotundirostris Jiang, Lin, Rieppel, Motani and Sun, 2019, is restudied on the basis of a second specimen from the Upper Member of the Guanling Formation near Panzhou City, Guizhou Province, China. The second specimen offers hitherto unknown or unconfirmed information regarding the dermal palate, the ventral aspect of the cervical vertebrae, and the hind limbs, thus permitting a refinement of the diagnosis. Newly added or modified diagnostic characters include paired frontals with no posterolateral process, elongated and slender phalanges in the manus and pes, and a phalangeal formula of 3-4-5-4-3 for the manus, and 2-3-4-5-3 for the pes. A new phylogenetic analysis of Eosauropterygia demonstrates that Pachypleurosauridae is the sister taxon of Eusauropterygia, and the monophyly of these groups as traditionally upheld is confirmed. Panzhousaurus is most closely related to Dianopachysaurus and Keichousaurus within Pachypleurosauridae. In this study, the monophyletic Pistosauroidea excludes Corosaurus and Cymatosaurus. The latter two genera are found to form a monophyletic clade that represents the basal-most members of Eusauropterygia, which is in accordance with their stratigraphic distribution.
During their long evolutionary history crocodylomorphs achieved a great diversity of body sizes, ecomorphotypes and inferred feeding ecologies. One unique group of crocodylomorphs are the thalattosuchians, which lived during the Jurassic and Cretaceous (ca. 191–125 Ma). They transitioned from shallow marine species, like teleosauroids, into fully pelagic forms with paddle shaped limbs and a vertically orientated tail fluke, the metriorhynchids. The osteological adaptations that allowed metriorhynchids to live in the water are generally well understood, but less is known about their neurosensory and endocranial systems, such as the brain, inner ears, sinuses and cranial nerves and how they relate to their aquatic lifestyle. Based on micro-computed tomography (µCT) data and three-dimensional models, we here describe the braincase and endocranial anatomy of a fully marine metriorhynchid, ‘Metriorhynchus’ cf. ‘M.’ brachyrhynchus (NHMUK PV OR 32617). We found several neuroanatomical features that likely helped this species function in its marine environment. These include a unique flexure in the brain endocast not seen in other thalattosuchians. Other features that have previously been seen in thalattosuchians include enlarged cerebral hemispheres, a hypertrophied venous sinus system, enlarged internal carotid arteries and foramina, and closed/absent lateral pharyngotympanic foramina. The specimen also possesses a pelagic metriorhynchid bony labyrinth morphology, with a compact and dorsoventrally short shape, thick semicircular canals, an enlarged vestibule and potentially a short cochlear duct. A review of character distribution confirms that some of these features evolved at the base of Thalattosuchia in semiaquatic species, long before metriorhynchids became pelagic, suggesting that endocranial anatomy helped allow metriorhynchoids colonize the ocean realm.
Tanius sinensis was one of the first dinosaur species to be named from China. It was established on a partial skeleton recovered by a joint Sino-Swedish expedition in 1923. The fossils were excavated from Upper Cretaceous strata of the Jiangjunding Formation (Wangshi Group) in Shandong Province, and although their discovery dates back almost 100 years, they have not been reassessed in detail since their initial description in 1929. This omission is critical because T. sinensis is now recognized as one of the stratigraphically youngest non-hadrosaurid hadrosauroid taxa. Here, we reevaluate the postcranial osteology of T. sinensis as a prelude to an anatomical and phylogenetic revision of the species. We examined the holotype and all currently referred specimens of T. sinensis first-hand, and identified a unique postcranial character state combination incorporating tall dorsal neural spines, a reduced postacetabular ridge on the ilium, a fully enclosed flexor tunnel formed by the distal condyles of the femur, and a lunate proximal end on metatarsal III. Comparisons with other species of Tanius confirm that: (1) T. chingkankouensis is a nomen dubium erected on non-diagnostic composite material; (2) T. laiyangensis was established on indeterminate hadrosaurid remains that are not attributable to Tanius; and (3) the anecdotal assignments of Bactrosaurus prynadai and Tsintaosaurus spinorhinus to Tanius cannot be substantiated. Close inspection of the holotype caudal vertebra further reveals a possible healed bite trace consistent with a prey–predator interaction. Lastly, our calculated average body mass estimate for T. sinensis of between 2091–3533 kg suggests that it was one of the largest non-hadrosaurid hadrosauroids.
Theropod dinosaurs are minor components of Late Triassic ecosystems in North America, comprising coelophysoids and various non-neotheropods from the Chinle Formation of Arizona, Utah, Colorado, and New Mexico and the Dockum Group of western Texas. By the Sinemurian (Early Jurassic), the coelophysoid “Syntarsus” kayentakatae and the large-bodied non-averostran neotheropod Dilophosaurus wetherilli from the Kayenta Formation were the dominant terrestrial predators. Theropods are virtually unknown from the intervening Rhaetian–Hettangian Moenave Formation, with the exception of two partial coelophysoid pelves from somewhere within the Dinosaur Canyon Member, which includes the Triassic–Jurassic boundary and end-Triassic mass extinction. Here we describe an anterior trunk vertebra from a non-coelophysoid, non-averostran neotheropod from the uppermost Whitmore Point Member of the Moenave Formation in southwestern Utah, which is Hettangian in age. The vertebra has prominent vertebral laminae and associated pneumatic fossae, and anterior and posterior ‘shoulders’ on the neural spine that are similar to those found in Dilophosaurus wetherilli. This vertebra belongs to a theropod that may be as many as 15 million years older than Dilophosaurus wetherilli from the middle of the Kayenta Formation in Arizona. This theropod is associated with Grallator, Eubrontes, and Characichnos theropod traces made on the shores of the Early Jurassic Lake Whitmore that are abundant in the Whitmore Point Member in southwestern Utah. Its occurrence in the Hettangian roughly coincides with the appearance of Eubrontes tracks in North America, indicating that not all contemporaneous theropod traces were made by coelophysoids.
Manuel Pérez-Pueyo, Eduardo Puértolas-Pascual, Miguel Moreno-Azanza, Penélope Cruzado-Caballero, José Manuel Gasca, Carmen Núñez-Lahuerta, José Ignacio Canudo
Throughout the evolutionary history of Avialae, several members of this clade have evolved into giant forms, in different time periods and ecological contexts. In Europe, the first birds that show this condition, the Gargantuaviidae, occur during the Late Cretaceous (late Campanian–early Maastrichtian), but it is during the Paleogene when more groups evolve large forms. However, until now, there was no record of any giant bird during the late Maastrichtian of Europe, close to the K/Pg boundary. Here we describe a cervical vertebra (MPZ 2019/264) from Beranuy (Huesca, NE Spain), which is the first fossil evidence of a giant bird from the late Maastrichtian of Europe, within Chron C29r. The vertebra displays some features, such as a well-marked heterocoelous articulation, lateral pneumatic foramina, ventral carotid processes, and a low neural spine, that support its inclusion within the clade Ornithuromorpha. This phylogenetic assignment is supported by two cladistic analyses. The vertebra is clearly different from the one assigned to Gargantuavis, meaning that it belonged to a distinct taxon. Although the kinship between these two taxa of giant birds is still unclear, this finding demonstrates that large-sized birds were part of the ecological communities of the Ibero-Armorican island from the late Campanian to the Late Maastrichtian, being present during the last hundreds of thousands of years prior to the K/Pg extinction event.
The Paleogene record of pelicans (Pelecanidae) is represented at present by a single early Oligocene specimen from southeastern France. Here we describe a new pelecanid from the early Priabonian portion of the Birket Qarun Formation within the Wadi Al-Hitan World Heritage Site in Egypt. This specimen, a nearly complete right tibiotarsus, is the first definitive pelecanid recovered from Eocene strata. The tibiotarsus is remarkably similar to those of known Pelecanus species, but sufficiently different to warrant designation as the new genus and species Eopelecanus aegyptiacus. This represents the oldest pelican described to date and extends the pelecanid fossil record by ca. 6 million years.
Permian dicynodonts were discovered in strata exposed on the flanks of the Bogda Mountains (Xinjiang, China) in 1928. Nearly all known specimens were collected in the Guodikeng Formation (= upper Wutonggou low-order cycle); the single exception is the holotype of Kunpania scopulusa, which originated in the underlying Quanzijie Formation. The Quanzijie Formation is generally considered Capitanian in age, which would make Kunpania one of the oldest known bidentalian dicynodonts, but the type of K. scopulusa has received little attention. Here we redescribe K. scopulusa and investigate its phylogenetic relationships. Kunpania scopulusa is a valid species diagnosed by the absence of anterior palatal ridges; a robust crista oesophagea; a prominent lateral dentary shelf; a posteriorly curving projection on the angular; and a large, triangular attachment area for M. latissimus dorsi on the humerus. Our phylogenetic analysis recovered K. scopulusa as a stemward member of Dicynodontoidea and the sister taxon of the South African species Sintocephalus alticeps. Depending on the precise age of the uppermost Quanzijie Formation, three scenarios describe the potential phylogenetic implications of K. scopulusa: (1) bidentalian dicynodonts diversified before the end-Guadalupian extinction, with little of their early history preserved; (2) the main diversifications of cryptodont and dicynodontoid bidentalians occurred in the aftermath of the end-Guadalupian extinction, with K. scopulusa representing the latter; (3) K. scopulusa is a contemporary of other mid–late Wuchiapingian dicynodontoids and the initial radiation of Dicynodontoidea is not preserved in the known fossil record.
Here, we report new dental remains of a large giraffid from the Late Miocene of Pakistan. The new material improves our knowledge of the dental morphology of this extinct sivatherine giraffid, as it sheds light on intra-clade morphological variability within Late Miocene sivatherine giraffids. Fossils were recovered from sediments within the Nagri and Dhok Pathan formations (Middle Siwaliks, Late Miocene) from the sites Nagri, Dhok Pathan, Kauliar and Padhri in Pakistan. Presence of these fossils in Late Miocene sediments in Pakistan demonstrates the stratigraphic range of Bramatherium grande, which was present in the Indo-Pakistani region and the Greco-Iranian region from 11.2 to ca. 3.4 Ma and 11.2 to 9.0 Ma, respectively. The new fossils provide additional data that help resolve the phylogenetic relationships of these large Late Miocene sivatheres. The new findings highlight the presence of Bramatherium grande in the Indo-Pakistani region during the Late Miocene and provide evidence for the synonymy of Bramatherium grande and Bramatherium magnum, with Bramatherium grande having priority.
The middle and late Eocene perissodactyl fossil record of western Iberia is characterized by an endemic fauna, which is clearly different from those of northeastern Iberia and other areas of the European archipelago. In this work, we describe three endemic equoid taxa belonging to the family Palaeotheriidae. Two come from the late Eocene site of Zambrana (Miranda-Treviño Basin, Araba/Álava, Spain) and correspond to new species: Leptolophus cuestai, sp. nov., and Leptolophus franzeni, sp. nov. Leptolophus cuestai, sp. nov. is the largest species of Leptolophus and exhibits thick coronal cementum and a very high hypsodonty index, unusual for an Eocene equoid. Leptolophus franzeni, sp. nov. is described from a cranium which includes the canines, which are otherwise unknown in Leptolophus. The third taxon, from the late middle Eocene site of Mazaterón (Almazán Basin, Soria, Spain), described provisionally as Leptolophus sp., could be another new Iberian species. The Iberian taxa are characterized by having: more hypsodont, lophodont and heterodont dentition than the Central European Leptolophus taxa (L. stehlini, L. nouleti and L. magnus); thicker styles and stylar ribs in the upper jugal teeth; and thicker coronal cementum. The precocious development of coronal cementum and the high hypsodonty index could be related to different foraging conditions (tougher vegetation, more open or drier habitats with a higher consumption of grit in the diet) inhabited by the Iberian Leptolophus species with respect to their Central European contemporaries.
Here we report a new cricetid s.l., Caecocricetodon yani, gen. et sp. nov., discovered in the early Oligocene of the Caijiachong Formation in Yunnan Province, China. The new cricetid differs from all known cricetids or stem muroids by its particular molar pattern displaying numerous crests and spurs. Our phylogenetic analysis based on a matrix including 42 taxa and 72 characters indicates that the new species has a close relationship with Paracricetodontinae, forming a monophyletic clade with Paracricetodon and Trakymys. The new cricetid also has a likely close relationship with Pappocricetodon. However, the genus Pappocricetodon is polyphyletic in our analysis. Considering the similarity of the brachydont lophodont teeth of Caecocricetodon and glirids, we propose that the new species underwent convergent evolution with dormice, possibly adapting to an arboreal ecological niche in Oligocene of southern China.
Sabertooth craniodental adaptations have evolved numerous times amongst carnivorous mammals. Some of the most extreme sabertooth adaptations are found within the carnivoran subfamily Barbourofelinae. However, the evolutionary origins of this group have been uncertain for more than 170 years, with variable placement as an independent case of sabertooth acquisition, as a clade within the Nimravidae (Eocene to Oligocene ‘false sabertooth cats’), or as a member of the Machairodontinae (true sabertooth cats such as Smilodon). Here we present a novel approach to assessing the validity of three independent sabertooth clades within Carnivora. We performed a total-evidence Bayesian analysis in Beast2 across all major carnivoran families, using the fossilized birth-death (FBD) model and incorporating 223 morphological characters, nuclear and mitochondrial gene sequences, and stratigraphic occurrence data. Our results place barbourofelines as terminal members of the Nimravidae, sister to the Nimravini (0.91 posterior probability), a relationship not found in prior cladistic studies. Ancestral area estimation performed in the R package BioGeoBEARS best supports a primarily European paleobiogeographic center for the barbourofelines with multiple dispersal events to other continents, a finding in direct opposition to past hypotheses for this group. Furthermore, new patterns in convergence between nimravids and machairodontines were revealed via Bayesian ancestral state estimation in BayesTraits. Results support a hypothesis of cats copying nimravids, and nimravids cats in certain aspects of sabertooth morphology, and not total evolutionary independence of these features as typically envisioned.
Leopardus is a genus that, despite currently being widely distributed in South America, shows until now a fragmentary fossil record. Among Leopardus, L. pardalis is the largest species, having an historical range that includes tropical and subtropical habitats from southern U.S.A. to southern South America but, as usual in the ocelot lineage, fossil remains that can be interpreted with certainty are restricted to the Late Pleistocene of southern U.S.A. and Brazil. Here we present a new record (a fragment of right maxillary plus zygomatic with P4–M1; incomplete left mandible with the coronoid process, part of c1 alveolus and p3–m1; isolated right c1) from the Late Pleistocene of Arroyo Toropí, Corrientes province, Argentina. The bearing level was dated with Optically Stimulated Luminescence (OSL) to 98.4 ka (Marine Isotopic Stage, MIS 5c). Present environmental requirements of L. pardalis and climatic reconstructions carried out here suggest a compatible scenario with MIS 5 for this fossil, which is concordant with the associated dating (ca. 98.4 ka). Leopardus pardalis appears to be part of a subtropical fauna, with Tayassu pecari and Euphractus sexcinctus, which inhabited the region during warm and wet climatic events of MIS 5c. Phytoliths and other vertebrates are congruent with its presence, since the inferred conditions are similar to the present one. The new record is relevant not only because it is the first fossil record of the species for the Pleistocene of Argentina, but also because it is placed 1800 km south of the closest accurately identified published fossil.
The first known primate fossil from the Atlantic Coastal Plain, a mandibular fragment representing the family Omomyidae, is described from the early Eocene Fisher/Sullivan Site in northeastern Virginia. The jaw, containing m1–m2, was found near the base of the Potapaco Member, Bed B, of the Nanjemoy Formation, indicating an early Ypresian age, ca. 54.5 Ma. As the specimen lacks diagnostic antemolar dentition, its precise identity cannot be confidently determined. However, its diminutive size and plesiomorphic molar morphology suggest that it represents a primitive omomyid. Comparison with a diversity of omomyids finds that nearly all omomyid genera are larger and/or derived in various features compared to the Nanjemoy specimen. Closest resemblances are to the primitive omomyids Steinius, Anemorhysis, Loveina, Melaneremia, and especially Teilhardina.
Dipnoan remains are mainly known from the Middle and Upper Devonian deposits in the Holy Cross Mountains, Poland. The presence of this group in the Lower Devonian was suggested by feeding trace fossils apparently made by dipnoan fish. Recent studies confirm the occurrence of body fossils based on single skeleton elements. Fragments of heavily ossified mandible and skull-roof represent dipnoan remains appear to belong to a primitive ‘Dipnorhynchus’-like form. It supplements the knowledge on the Early Devonian ecosystem at the Holy Cross Mountains and dipnoan ichnological record is now supported by fossil remains of a putative trace-maker for Osculichnus isp.
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