Hindeodus parvus and Hindeodus typicalis occur in a deep-water chert and claystone section in the Mino Terrane, Japan, which has been identified as a Jurassic accretionary complex. Conodont fossils are preserved as natural assemblages of impression fossils on bedding planes in claystone. In this study, 13 assemblages of Hindeodus species were recognized, comprising at most 13 elements which generally maintain the original composition and structure of an apparatus. We discriminated pairs of carminiscaphate P 1 , angulate P 2 and makellate M elements, as well as a single alate S 0 element and two digyrate and four bipennate elements constituting the S array. Although the digyrate and bipennate elements are preserved in the S 2 and S 3-4 positions, respectively, a pair of S 1 elements was not found due to incompleteness in the natural assemblages. The conodont biostratigraphy indicates that the lithological boundary between chert and claystone units in the study section corresponds exactly to the Permian-Triassic boundary.

The apparatus of an Early Triassic conodont Neostrachanognathus tahoensis Koike, 1998 from Oritate, Kumamoto Prefecture, Japan, and a species of Neostrachanognathus from Oman were reconstructed. On the basis of five natural assemblages from the Oritate area, the threedimensional apparatus model of N. tahoensis is interpreted as bilaterally symmetrical and composed of 14 elements consisting of pairs of P 1 , P 2 , P 3 , S 1 , S 2 , S 3 , and S 4 elements. The P 1 and P 2 elements are coniform elements, the P 3 elements are digyrate forms, and the S elements are bipennate ramiforms. The S elements are arranged rostrally in the apparatus and the pairs of the P 1 , P 2 , and P 3 elements are subvertically arranged caudally and ventrally to the S array. One of the natural assemblages was formed by rostrocaudal collapse of the apparatus on the sea floor, whereas the other assemblages indicate that conodont animals came to rest nearly parallel with the substrate prior to burial. A collection of isolated elements from Jabal Safra, Oman, includes a second species of Neostrachanognathus with a comparable apparatus.

We describe the lithology and age of an intact section (NF 1212R) and two reference sections of Panthalassan seamount-associated Permian-Triassic boundary (PTB) siliceous rocks. The sections occupy the upper part of the Hashikadani Formation of the Mino terrane in the Mt. Funabuseyama area, central Japan. Section NF 1212R comprises a lower unit of gray chert (ca. 1.7 m thick), a middle unit of dark gray to black chert (ca. 0.8 m) with a pyrite-rich layer at the top (ca. 0.1 m), and an upper unit of black claystone with thin, intermittent beds of black to dark gray chert (ca. 1.2 m), in ascending order. The chert of the lower and middle units is rich in radiolarian remains with minor siliceous sponge spicules. The black chert of the middle unit is carbonaceous and includes tiny pyrite grains. The black claystone consists of microcrystalline quartz and clay minerals rich in carbonaceous matter. The chert of the upper unit is also carbonaceous and rich in radiolarian remains. The lower and middle units are correlated with the Neoalbaillella optima Zone (Changhsingian). The basal part of the upper unit is referable to the Hindeodus parvus Zone (basal Griesbachian), and the major part of the upper unit is possibly correlated with the middle to upper Dienerian. We position the PTB at the sharp lithologic boundary between the upper Upper Permian chert and lower Lower Triassic black claystone. The examined PTB siliceous rocks are stratigraphically attributed to the upper part of the Hashikadani Formation, reconstructed as an oceanic rock unit characterized by Lower Permian to Lower Triassic siliceous rocks that accumulated upon the lower flank of a mid-oceanic seamount in a pelagic realm of the Panthalassa Ocean. Our results present the world's first record of deep-marine PTB siliceous rocks associated with a Panthalassan seamount.

The Middle and Upper Ordovician sequence of the Langkawi Islands, northwestern peninsular Malaysia, contains 20 species of conodonts belonging to 15 genera and four unidentified species, which are described and illustrated. The following four biostratigraphic zones are established for the study area: the Scolopodus striatus assemblage zone, the Periodon sp. A range zone, the Baltoniodus alobatus range zone, and the Hamarodus europaeus range zone, in ascending order. The Middle Ordovician fauna belongs to the low-latitude, warm-water Australian Province. Conodonts of the H. europaeus zone represent the HDS (Hamarodus europaeus-Dapsilodus mutatus-Scabbardella altipes) biofacies, which has been reported from the cool-water North Atlantic Faunal Region. The middle Arenigian limestones in the study area were deposited on a shallow-water shelf, whereas the late Arenigian to middle Darriwilian limestones formed in hemipelagic deeper-water conditions on an outer shelf or slope.

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