A fresh look at Cladarosymblema narrienense, a tetrapodomorph fish (Sarcopterygii: Megalichthyidae) from the Carboniferous of Australia, illuminated via X-ray tomography

Background The megalichthyids are one of several clades of extinct tetrapodomorph fish that lived throughout the Devonian–Permian periods. They are advanced “osteolepidid-grade” fishes that lived in freshwater swamp and lake environments, with some taxa growing to very large sizes. They bear cosmine-covered bones and a large premaxillary tusk that lies lingually to a row of small teeth. Diagnosis of the family remains controversial with various authors revising it several times in recent works. There are fewer than 10 genera known globally, and only one member definitively identified from Gondwana. Cladarosymblema narrienense Fox et al. 1995 was described from the Lower Carboniferous Raymond Formation in Queensland, Australia, on the basis of several well-preserved specimens. Despite this detailed work, several aspects of its anatomy remain undescribed. Methods Two especially well-preserved 3D fossils of Cladarosymblema narrienense, including the holotype specimen, are scanned using synchrotron or micro-computed tomography (µCT), and 3D modelled using specialist segmentation and visualisation software. New anatomical detail, in particular internal anatomy, is revealed for the first time in this taxon. A novel phylogenetic matrix, adapted from other recent work on tetrapodomorphs, is used to clarify the interrelationships of the megalichthyids and confirm the phylogenetic position of C. narrienense. Results Never before seen morphological details of the palate, hyoid arch, basibranchial skeleton, pectoral girdle and axial skeleton are revealed and described. Several additional features are confirmed or updated from the original description. Moreover, the first full, virtual cranial endocast of any tetrapodomorph fish is presented and described, giving insight into the early neural adaptations in this group. Phylogenetic analysis confirms the monophyly of the Megalichthyidae with seven genera included (Askerichthys, Cladarosymblema, Ectosteorhachis, Mahalalepis, Megalichthys, Palatinichthys, and Sengoerichthys). The position of the megalichthyids as sister group to canowindrids, crownward of “osteolepidids” (e.g.,Osteolepis and Gogonasus), but below “tristichopterids” such as Eusthenopteron is confirmed, but our findings suggest further work is required to resolve megalichthyid interrelationships.

Palladothallite, Pd3Tl, a new mineral from the Monchetundra layered intrusion, Kola Peninsula, Russia

ABSTRACT Palladothallite, Pd3Tl, is a new mineral discovered in the Monchetundra layered intrusion, Kola Peninsula, Russia. Palladothallite occurs in orthopyroxenite with disseminated Ni-Cu-Fe sulfides and in near-surface oxidized ore of an orthopyroxenite unit. In the holotype specimen, the new mineral forms anhedral grains about 1 to 20 μm in size intergrown with bortnikovite (Pt4Cu3Zn). Palladothallite and bortnikovite form a rim around tulameenite (Pt2FeCu), Pt-Pd-Fe-Cu alloys, and Pt-Pd-Fe-Cu “oxides” in a goethite matrix. In plane-polarized light, palladothallite is white, anisotropy was not observed; it exhibits no internal reflections. Reflectance values of palladothallite in air (R' in %) are: 53.9 at 470 nm, 57.1 at 546 nm, 59.4 at 589 nm and 61.7 at 650 nm. Twelve electron probe microanalyses of palladothallite gave an average composition (in wt.%): Pd 59.99, Cu 1.19, Fe 0.35, Ag 1.1, Tl 35.64, Se 0.34, and S 0.09, total 99.67, corresponding to the empirical formula (Pd2.894Cu0.096Fe0.032Ag0.053)∑3.075(Tl0.895Se0.023S0.008)∑0.926 based on four atoms, with the ideal formula Pd3Tl. The density, calculated on the basis of the empirical formula, is 13.04 g/cm3. Palladothallite crystallizes with the same structure as synthetic Pd3Tl, which was solved by Kurtzemann & Kohlmann (2010) from powder neutron diffraction data. Palladothallite is tetragonal, space group I4/mmm, with a 4.10659(9), c 15.3028(4) Å, V 258.07(1) Å3, and Z = 4. Palladothallite crystallizes in the ZrAl3 structure type. The name corresponds to its chemical composition, palladium and thallium.

Postcranial osteology of Beipiaosaurus inexpectus (Theropoda: Therizinosauria)

Beipiaosaurus inexpectus, from the Lower Cretaceous Yixian Formation (Sihetun locality, near Beipiao), Liaoning, China, is a key taxon for understanding the early evolution of therizinosaurians. Since initial publication in 1999, only the cranial elements of this taxon have been described in detail. Here we present a detailed description of the postcranial skeletal anatomy of the holotype specimen of B. inexpectus, including two never before described dorsal vertebrae from the anterior half of the series. Based on these observations, and comparisons with the postcranial skeleton of therizinosaurian taxa named since the most recent diagnosis, we revised the diagnostic features for B. inexpectus adding three new possible autapomorphies (PII-3 shorter than PIII-4, subequal length of the pre- and postacetabular portions of the ilium, and equidimensional pubic peduncle of ilium). Additionally, we also propose three possible synapomorphies for more inclusive taxa (Therizinosauroidea and Therizinosauridae) and discuss implications for evolutionary trends within Therizinosauria. The newly acquired data from the postcranial osteology of the holotype specimen of B. inexpectus sheds light on our understanding of postcranial skeletal evolution and identification of therizinosaurians.

Liraite, ideally NaCa2Mn2[Fe3+Fe2+]Mn2(PO4)6(H2O)2, a new phosphate mineral of the wicksite group from the Ceferino Namuncurá pegmatite, Córdoba, Argentina

ABSTRACT Liraite, ideally NaCa2Mn2[Fe3+Fe2+]Mn2(PO4)6(H2O)2, is a new mineral found in the Ceferino Namuncurá pegmatite, Pocho Department, Córdoba province, Argentina. It occurs in ellipsoidal nodules up to 20 cm in diameter in the intermediate zone of a Muscovite-Rare Element class pegmatite. Secondary phosphates, such as varulite, robertsite, fluorapatite, phosphosiderite, and Sr-rich metaswitzerite, together with minor quartz in veinlets, are associated minerals. Liraite is interpreted to have formed by reaction of phosphate minerals with Na-bearing hydrothermal fluids. It is dark brown with greenish hues (nearly black) in massive aggregates and dark olive green in translucent slices with a dark brownish green streak and a vitreous luster. It is brittle with an irregular fracture, one very good cleavage, and a good cleavage orthogonal to the very good cleavage. The Mohs hardness is 5, and the measured and calculated densities are 3.52(1) and 3.529(1) g/cm3, respectively. In transmitted light it is pleochroic X = Y = olive, Z = yellowish brown with X = Y > Z and optical orientation X = 2V(calc.) = 69.2°. The refractive indicies measured with monochromatic light (λ = 589 nm) are α = 1.732 (3), β = 1.739 (3), γ = 1.754 (3). Liraite is orthorhombic (Pcab) and has unit-cell parameters a = 12.608(6) Å, b = 12.918(6) Å, c = 11.737(4) Å, V = 1911.6(14) Å3, Z = 4. The six strongest reflections in the X-ray powder diffraction pattern are as follows: [d in Å, (I), (hkl)] 2.7452, 100, (421); 2.8563, 65, (014); 2.9266, 49, (004); 2.7061, 30, (412); 2.0966, 29, (334); 2.7693, 26, (402). The crystal structure was refined to an R index of 1.94% based on 2910 observed (>4σF) reflections measured with MoKα X-radiation. Chemical analysis by electron microprobe of the structure crystal (holotype specimen) gave Na2O 1.58, FeO 5.29, Fe2O3 11.45, CaO 10.52, MgO 0.77, MnO 24.00, P2O5 41.55, SrO 0.72, ZnO 0.19, H2O (calc.) 3.50, total 99.57 wt.% where water was calculated from the crystal-structure analysis and the Fe3+/Fe2+ ratio was determined by charge balance. The empirical formula calculated on the basis of 26 oxygen atoms is (Na0.53□0.47)Σ1.00(Ca1.93Sr0.07)Σ2.00(Fe3+1.48Fe2+0.76Mn3.48Mg0.20Zn0.02)Σ5.94P6.02O24(H2O)2, ideally NaCa2M(1)Mn2M(2)[Fe3+Fe+2]M(3)Mn2(PO4)6(H2O)2. The Gladstone-Dale relation gives a compatibility index of 1 – (KP/KC) = 0.010 (superior). This new member of the wicksite group is Mn-rich, and, like bederite, has Mn dominant at the M(1) and M(3) sites. However, the Na site in liraite is Na-dominant with M(2)[Fe3+Fe2+], whereas bederite is □-dominant with M(2)Fe3+2. Liraite has a very low MgO content, and even with all available Mg assigned to the M(2) site, Fe2+ > Mg at M(2). Consequently, liraite is the first wicksite-group mineral with endmember M(2) composition [Fe3+Fe2+].

First record of a tomistomine crocodylian from Australia

Based on the known fossil record, the majority of crocodylians from the Cenozoic Era of Australia are referred to the extinct clade Mekosuchinae. The only extant crocodylians in Australia are two species of Crocodylus. Hence, the viewpoint that Crocodylus and mekosuchines have been the only crocodylians inhabiting Australia during the Cenozoic has remained largely undisputed. Herein we describe Australia’s first tomistomine crocodylian, Gunggamarandu maunala gen. et sp. nov., thus challenging the notion of mekosuchine dominance during most of the Cenozoic. The holotype specimen of Gunggamarandu maunala derives from the Pliocene or Pleistocene of south-eastern Queensland, marking the southern-most global record for Tomistominae. Gunggamarandu maunala is known from a large, incomplete cranium that possesses a unique combination of features that distinguishes it from other crocodylians. Phylogenetic analyses place Gunggamarandu in a basal position within Tomistominae, specifically as a sister taxon to Dollosuchoides from the Eocene of Europe. These results hint at a potential ghost lineage between European and Australian tomistomines going back more than 50 million years. The cranial proportions of the Gunggamarandu maunala holotype specimen indicate it is the largest crocodyliform yet discovered from Australia.

Cesiokenopyrochlore, the First Natural Niobate with an Inverse Pyrochlore Structure

Cesiokenopyrochlore is a new mineral belonging to the pyrochlore group. It was discovered in a specimen of granitic pegmatite collected at Tetezantsio, Betafo region, Madagascar. The mineral forms rough equant crystals up to 0.05 mm in size intergrown with béhierite and rynersonite. Cesiokenopyrochlore is light-brown, translucent, with resinous luster. Dcalc. = 5.984 g/cm3. In reflected light it is light gray, isotropic, with strong light-brown internal reflections. The crystal structure was refined to R1 = 0.0212. The mineral is cubic, , a = 10.444(1) Å, V = 1139.5(2) Å3, and Z = 8. The strongest lines of the powder X-ray diffraction pattern [d, Å, (I, %) (hkl)] are: 6.03 (37) (111), 3.70 (9) (220), 3.15 (100) (311), 3.02 (36) (222), 2.012 (17) (511, 333), 1.848 (19) (440), 1.576 (11) (622). The chemical composition is (wt.%; electron microprobe): Cs2O 22.66, Na2O 1.74, CaO 0.64, Nb2O5 20.87, Ta2O5 21.27, WO3 30.67, H2O (calc) 0.12, total 97.97. The empirical formula of the holotype specimen calculated on the basis of (Nb+Ta+W) = 2 apfu and (O+OH) = 6 apfu and written according to the pyrochlore-supergroup nomenclature is Na0.29Ca0.06(Nb0.81W0.69Ta0.50)Σ2[O5.93(OH)0.07]Σ6Cs0.83. The simplified formula of the holotype specimen is □2(Nb,W,Ta)Σ2O6Cs. Cesiokenopyrochlore is the first natural niobate to adopt the inverse pyrochlore structure.

A new epiphytic species, Symphytocarpus macrosporus (Myxomycetes) from Western Siberia, Russia

A new species <em>Symphytocarpus macrosporus</em> is described based on collections made in the Khanty- Mansi Autonomous Area – Yugra, Russia. Thirty- two specimens of the new species were isolated from moist chambers with <em>Picea obovata</em> and <em>Abies siberica</em> bark. The new species is characterized by the presence of pseudoaethalia, without cortex, with peridium remaining as fragments. This new species clearly differs from previously described species of the genus by both morphological and molecular characters. It has large spores, (14)15–17(18) μm diam. with irregular ornamentation of large warts. Such a spore size seems to be the largest for the genus. The holotype specimen of <em>Symphytocarpus macrosporus</em> is stored in the M.G. Popov Herbarium (NSK), Novosibirsk, Russia. It is the first new species described within the genus <em>Symphytocarpus</em> since 1984.

Cercosporella bundelkhandae comb. nov. from India

The new combination Cercosporella bundelkhandae (≡ Pseudocercosporella bundelkhandae) is proposed, based on critical morphological re-examination of the holotype specimen and fresh topotypic material and comparison with closely related species of cercosporoid hyphomycetes. The species was originally collected on living leaves of Tinospora sinensis from Jhansi, Utttar Pradesh, India.