Ungula

Abstract: EMIG (2002) re-examined the taxonomy of the genus Obolus EICHWALD from the Middle Cambrian - earliest Ordovician of the East Baltic region as part of a proposal for a wholesale revision of the principles of linguloid systematics. He contended that previous taxonomic studies on Obolus and related forms were carried out erroneously using characters that have no taxonomic value. EMIGs proposed revision is based mainly on the limited morphological diversity between fossil and Recent taxa within a single linguloid Family, the Lingulidae. However, the present study demonstrates the taxonomic validity of the diagnostic characters used for classification within the mostly extinct families of the Superfamily Linguloidea, for they exhibit far more variation in morphology. This study also shows that EMIG has provided no satisfactory basis for his radical changes and revisions to the existing widely accepted taxonomy of the Cambrian to earliest Ordovician Obolidae of the East Baltic. Obolus E ICHWALD and Ungula P ANDER are shown to constitute distinctive and discrete genera comprising the species Obolus apollinis EICHWALD, O. ruchini KHAZANOVITCH et POPOV, O. transversus (PANDER), Ungula ingrica (EICHWALD), U. inornata (MICKWITZ), and U. convexa PANDER.

Abstract: Shell structures of Ungula ingrica, U. inornata, and Ungula sp. 1 (Kallavere and Ulgase formations) from Cambrian sandstones of the Maekalda section in Tallinn, Estonia, were studied. Specific alterations were recorded in the shell structures of U. ingrica and Ungula sp. 1. Several generations of precipitation of phosphatic matter inside the shells could be distinguished, marking (1) original biomineralization events, (2) phosphatization of soft tissues, and (3) later diagenetic alteration of mineral matter and/or structures inside the shells. The shells of U. inornata and U. ingrica were found to represent the baculate structure type typical of the genus. The shell structure of Ungula sp. 1 is different, consisting of alternating compact and primarily organic-rich laminae. No bacula were found in the latter laminae. Compact laminae are penetrated by tubuli, filled with phosphatized organic matter. This structure type is termed here as tubulate shell structure.

Abstract: Introduction Reindeer are adapted to long distance migration. This species can cope with variations in substrate, especially in ice and snow environment. However, few detailed studies about reindeer hoof are available. Thus this article describes the results of studies on macro- and micro-structures of reindeer hoof. Material and Methods The gross anatomy of the reindeer hooves was examined. Stereo microscope (SM) and a scanning electron microscope (SEM) were used to observe four key selected positions of reindeer hooves. Moreover, element contents of the three selected positions of reindeer hooves were analysed using the SEM equipped with energy dispersive spectroscope. Results Hoof bone structures were similar to other artiodactyl animals. In the microscopic analysis, the surfaces of the ungula sphere and ungula sole presented irregular laminated structure. Ungula edge surfaces were smooth and ungula cusp surfaces had unique features. Aside from C, O, and N, reindeer hooves contained such elements as S, Si, Fe, Al, and Ca. The content of the elements in different parts varied. Ti was the particular element in the ungula sole, and ungula edge lacked Mg and S which other parts contained. Conclusion The macro- and micro-structures of the reindeer hooves showed high performance of skid and abrasion resistance. It is most probably essential to the long distance migration for the animals.

Abstract: The brachiopod fauna from the base of the Bryn Siltstone Formation (middle Caradoc), Glyn Ceiriog, north Berwyn Hills, North Wales, consists of Platystrophia elevata sp. nov., Salopia abbreviata sp. nov., Kiaeromena ungula (M'Coy) and unnamed species of Hesperorthis?, Reuschella and Bicuspina. The dominant brachiopod species, Leptaena (Leptagonia) ungula M'Coy, 1851 is revised and its current assignment to the leptaenid genus Kiaeromena confirmed, based on the examination of type and topotype material from the Bryn Siltstone Formation. Kiaeromena spjeldnaesi nom. nov. is proposed to replace the junior homonym K. ungula Spjeldnaes, 1957 for that congeneric species from the upper Caradoc rocks of Ringerike, southern Norway. The fauna as a whole is unusual within the context of the Anglo-Welsh province and may represent a rare preserved nearshore community.