分类： 生物学 >> 动物学 提交时间： 2021-05-20 合作期刊: 《古脊椎动物学报》
摘要： Actinopterygii, the largest group of extant vertebrates, includes Cladistia, Actinopteri (Chondrostei plus Neopterygii) and closely related fossil taxa. The extinct genus Pteronisculus belongs to a stem lineage of actinopterygian fishes represented by 11 species from the Early Triassic of Madagascar, Europe and North America, and a single species from the early Middle Triassic of China. Here, we report the discovery of a new species of this genus, Pteronisculus changae, on the basis of five well-preserved specimens from the Middle Triassic (Anisian) marine deposits exposed in Luoping, eastern Yunnan, China. The discovery documents the second convincing species of Pteronisculus in the Middle Triassic and the largest stem actinopterygian fish in the Luoping Biota, having a maximum total length of up to 295 mm. The new species possesses a toothed lacrimal, which is characteristic of Pteronisculus, but it is easily distinguished from other species of the genus by some autapomorphies, e.g., a medial process at the middle portion of the intertemporal, 21 supraneurals, and 83 lateral line scales. The results of our cladistic analysis provide new insights into the relationships of early actinopterygians and recover Pteronisculus as a sister taxon of the Carboniferous rhadinichthyid Cyranorhis at the actinopterygian stem. Based on the body form, teeth and other features, it can be deduced that Pteronisculus changae is likely a relatively fast-swimming predator, feeding on planktonic invertebrates and smaller or younger fishes known to occur in the same biota. As one of the youngest species of the genus, the new species provides additional evidence to suggest that the diversity of Pteronisculus is higher than previously thought and that the eastern Paleotethys Ocean likely constituted a refuge for species of this genus during the early Middle Triassic.
分类： 生物学 >> 生物进化论 提交时间： 2024-03-15
摘要： The previously alleged ‘eugnathid amiiform’ Sinoeugnathus kueichowensis is asmall-sized halecomorph from the Middle Triassic (Ladinian) marine deposits of Guizhou andYunnan, China. A morphological redescription and taxonomic revision of this taxon are providedbased on a detailed examination of 15 new specimens. Among them, IVPP V24315 (standardlength = 64 mm) is appointed as the neotype, given that the holotype is missing. Studies of thesespecimens revealed some morphological details previously undescribed or misidentified forthis taxon, including a hatchet-shaped antorbital, two broad suborbitals, a sensory canal in themaxilla, and three pairs of extrascapulars. For the first time, Sinoeugnathus was incorporatedinto an analysis of halecomorph phylogeny, and the results recover it as the sister taxon of theAnisian Subortichthys from Luoping, Yunnan, and both are grouped with two Ladinian generaAllolepidotus and Eoeugnathus from the Monte San Giorgio area into a monophyletic group(namely Subortichthyidae fam. nov. herein) at the base of Ionoscopiformes. This taxonomicreassessment of Subortichthys provides new insights into the phylogeny and paleogeographicevolution of Ionoscopiformes.
分类： 生物学 >> 动物学 提交时间： 2023-07-12 合作期刊: 《古脊椎动物学报》
摘要： The previously alleged eugnathid amiiform Sinoeugnathus kueichowensis is a small-sized halecomorph from the Middle Triassic (Ladinian) marine deposits of Guizhou and Yunnan, China. A morphological redescription and taxonomic revision of this taxon are provided based on a detailed examination of 15 new specimens. Among them, IVPP V24315 (standard length = 64 mm) is appointed as the neotype, given that the holotype is missing. Studies of these specimens revealed some morphological details previously undescribed or misidentified for this taxon, including a hatchet-shaped antorbital, two broad suborbitals, a sensory canal in the maxilla, and three pairs of extrascapulars. For the first time, Sinoeugnathus was incorporated into an analysis of halecomorph phylogeny, and the results recover it as the sister taxon of the Anisian Subortichthys from Luoping, Yunnan, and both are grouped with two Ladinian genera Allolepidotus and Eoeugnathus from the Monte San Giorgio area into a monophyletic group (namely Subortichthyidae fam. nov. herein) at the base of Ionoscopiformes. This taxonomic reassessment of Subortichthys provides new insights into the phylogeny and paleogeographic evolution of Ionoscopiformes.
分类： 化学 >> 物理化学 提交时间： 2017-11-05 合作期刊: 《结构化学》
摘要： Two alkaline earth metal coordination polymers [M(2-Hstp)(H2O)] (M = Ca2+ (1) and Sr2+ (2), 2-H3stp = 2-sulfoterephthalate) were synthesized under hydrothermal conditions by the precursor [Mn(2-Hstp)2(4,4΄-Hbpy)2] and alkaline earth metal salts. The two alkaline earth complexes are not isomorphic. Complex 1 crystallizes in the monoclinic space group P21/m, while 2 in the monoclinic space group P21/c, despite of their similar formulas. In 1, the Ca2+ ion lies in a seven-coordinated pentagon bipyramidal configuration, coordinated with five 2-Hstp2- anions and one water molecule. However, the Sr2+ ion in 2 is coordinated by nine oxygen atoms to form a single-capped square antiprism polyhedron. Both 1 and 2 exhibit π-π* emission of the 2-sulfoterephthalate ligand.
分类： 化学 >> 物理化学 提交时间： 2017-11-05 合作期刊: 《结构化学》
摘要： Two coordination polymers (CPs), {[Ag(ADA)0.5(DPE)]·H2O}n (1) and {[Ag(ADA)0.5(Bipy)0.5]·H2O}n (2), (H2ADA = 3,3-azodibenzoic acid, DPE = 1,2-di(4-pyridyl)- ethylene, Bipy = 4,4΄-bipyridine), have been synthesized via solvothermal reactions of Ag+ with ADA2- and/or DPE, Bipy. CPs 1 and 2 were characterized by elemental analyses, IR spectra, thermal behaviors, and X-ray single-crystal diffraction. CPs 1 and 2 feature “Ag···Ag” subunits. CP 1 shows a 3D construction, in which the “Ag···Ag” subunits extend through ADA2- and DPE ligands using μ6-kO,O;kO;kO;kO,O;kO;kO and μ2-kO;kO coordination modes, respectively. It crystallizes in triclinic system, space group P, with a = 0.3808(18), b = 1.2476(6), c = 1.309(6) nm, α = 76.757(5), β = 84.649(5), γ = 86.809(5)º, V = 0.6024(5) nm3, Z = 2, Mr = 351.11, C13H11AgN2O3, Dc = 1.936 g/cm3, F(000) = 348, S = 1.064, R = 0.0323 and wR = 0.0689. CP 2 exhibits a 3D supramolecular structure, in which the “Ag···Ag” subunits are connected by ADA2- and DPE ligands with μ6-kO;kO;kO,O;kO;kO and μ2-kO;kO coordination modes, respectively. Ultimately, through hydrogen bond and π···π interaction, the “Ag···Ag” subunits stabilize the 3D supramolecular structure of 2. It crystallizes in monoclinic, space group C2/c, with a = 25.301(15), b = 13.197(8), c = 6.970(4) nm, β = 102.597(7)º, V = 2.271(2) nm3, Z = 8, C12H10AgN2O2.50, Mr = 330.09, Dc = 1.931 g/cm3, F(000) = 1304, S = 1.082, R = 0.1107 and wR = 0.2984. The fluorescence properties of CPs 1 and 2 have been also investigated.
分类： 化学 >> 物理化学 提交时间： 2017-11-05 合作期刊: 《结构化学》
摘要： One new coordination polymer (CP) [Cd(bct)(bib)]·2(H2O) (1), based on 3,5-bis(4΄-carboxy- phenyl)-1,2,4-triazole (H2bct) and 1,4-bis(imidazol-1-ylmethyl)benzene(bib), has been synthesized by hydrothermal method, and its structure was determined and characterized by single-crystal X-ray diffraction analysis, elemental analysis, IR spectroscopy, and thermogravimetric analysis. The crystal structure of CP 1 is a three-dimensional framework with (3,5)-connected topology, where the bct ligands adopt a µ3-kO,kO,kO coordination mode connecting with three Cd centers and the bib ligands adopt a µ2-kN,kN coordination mode bridging two Cd ions. It crystallizes in monoclinic system, space group C2/c, with a = 2.6838(4), b = 1.24221(17), c = 1.8011(2) nm, β = 102.939(2)º, V = 5.8522(13) nm3, Z = 8, C30H27CdN7O6, Mr = 694.00, Dc = 1.566 g/cm3, F(000) = 2784, S = 1.055, R = 0.0294 and wR = 0.0731. Furthermore, solid-state photoluminescence measurements show that CP 1 produces strong emissions at room temperature.
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