Bull. nat. Hist. Mus. Lond. (Geol.) 54( 1 ): 33-107 j^^^gj 25 June 1998 



Ammonites and nautiloids from the Jurassic 

 and Lower Cretaceous of Wadi Hajar, 

 southern Yemen 



MICHAEL K. HOWARTH^ ^ 



Department of Palaeontology, The Natural History Museum, Cromwell Road, London SW7 5BD 



CONTENTS 



Introduction 



34 



Systematic Descriptions 34 



Order Ammonoidea Zittel, 1884 35 



Family Oppeliidae Douville. 1890 35 



Genus Taramelliceras Del Campana, 1904 35 



Genus Strehlites Hyatt, 1900 39 



Genus Uhligites Kilian, 1907 39 



Family Haploceratidae Zittel, 1884 39 



Genus Haploceras Zittel, 1870 39 



Genus Glochiceras Hyatt, 1900 43 



Family Sphaeoceratidae Buckman, 1920 44 



Genus Epimayaites Spath, 1928 44 



Genus Paiyphoceras Spath. 1928 44 



Family Perisphinctidae Steinmann, 1890 45 



Genus Larcheria Tintant, 1961 45 



Genus Orthosphinctes Schindewolf, 1925 45 



Genus Torquatisphinctes Spath, 1924 45 



Genus Katroliceras Spath, 1924 47 



Genus Subdichotomoceras Spath, 1925 49 



Genus Sutneria Zittel, 1884 50 



Genus Pachysphinctes Dietrich, 1925 50 



Genus Idoceras Burckhardt, 1906 56 



Genus Nebrodites Burckhardt, 1912 60 



Family Pachyceratidae Buckman, 1918 62 



Genus Erymnoceras Hyatt, 1900 62 



Family Aspidoceratidae Zittel, 1895 63 



Genus Aspidoceras Zittel, 1868 63 



Genus Orthaspidoceras Spath, 1925 68 



Genus Simaspidoceras Spath, 1925 70 



Genus Hybonoticeras Breistroffer, 1947 74 



Family Simoceratidae Spath, 1924 76 



Genus Pseudoclambites Spath, 1925 76 



Genus Baeticoceras Geyssant, 1979 78 



Genus Virgatosimoceras Spath, 1925 78 



Family Himalayitidae Spath, 1925 79 



Genus Aulacosphinctes Uhlig, 1910 79 



Genus Micracanthoceras Spath, 1925 79 



Genus Himalayites Boehm, 1904 79 



Family Olcostephanidae Pavlow, 1892 79 



Genus 5p/«cera^ Uhlig, 1903 79 



Family Ataxioceratidae Buckman, 1921 84 



Genus Crussoliceras Enay, 1959 84 



Genus Z,i?/;acoc(?ra,? Hyatt, 1900 85 



Genus Virgatosphinctes Uhlig, 1910 88 



Genus Choicensisphinctes Leanza, 1980 88 



Family Neocomitidae Salfeld, 1921 90 



Genus BerriasellaVihW^. 1905 90 



Genus Substeueroceras Spath, 1923 91 



Genus Riasanites Spath, 1923 93 



Genus Blanfordiceras Cossmann, 1907 94 



© The Natural History Museum, 1? 



