<i>Shajia</i>, a new genus of polyconitid rudist from the Langshan Formation of the Lhasa Block, Tibet, and its palaeogeographical implications

A new polyconitid rudist Shajia tibetica gen. et sp. nov., of late Aptian to Albian age, is described from the Langshan Formation of Nyima County, northern Lhasa Block, Tibet. Though comparable in size and external morphology with Horiopleura haydeni Douvillé, which is a common endemic species in southwestern Asia, Shajia differs from the latter species in its possession of an inwardly inclined, instead of outwardly facing, posterior myophore in the right valve. In addition, a single specimen from Ladakh, which was previously assigned to Polyconites? sp., on account of a similar myophoral distinction from H. haydeni, is transferred to the new genus. Shajia is considered most likely to have been derived from one of a group of Horiopleura species that lived on the southern margin of the Mediterranean Tethys. The so-called ‘Yasin fauna’ represented by the late Aptian to Albian Horiopleura haydeni/ Auroradiolites gilgitensis rudist association, is considered to be restricted to southwestern Asia, including Afghanistan, Kohistan in northern Pakistan and Ladakh in northern India, though those two species in particular have not so far been recorded from the Lhasa Block of Tibet. Nevertheless, S. tibetica co-occurs with Auroradiolites biconvexus (Yang et al.), which probably evolved directly from A. gilgitensis (Douvillé), and the age of the latter association is in accordance with the generally accepted age of the Yasin fauna as late Aptian to Albian. Hence the S. tibetica and A. biconvexus association can be considered a regional variant of the Yasin fauna, which had evidently already dispersed to the Lhasa Block by the late Aptian. So the Langshan Formation can be considered palaeogeographically linked with other mid-Cretaceous shallow-marine carbonate deposits in adjacent southwestern Asian regions. These findings also provide new evidence that the age of the rudist assemblage of the Lhasa Block is late Aptian to Albian, although a slightly younger age cannot be excluded

Sur quelques Rudistes d’Egypte.

Douvillé Henri. Sur quelques Rudistes d’Egypte. In: Bulletin de l'institut égyptien, tome 8, premier fascicule, 1914. pp. 162-167

Les Foraminifères de l’île de Nias

On voit que les terrains suivants sont représentés dans l’île de Nias: 1°. Lutétien moyen, caractérisé par: Numm. lævigatus, N. Lamarcki?, N. bagelensis, N. kelatensis, Assilina granulosa, Ass. orientalis, Orthophragmina decipiens, Alveolina javana. Ces couches représentent le prolongement de l’étage des brèches de Sumatra, dont l’âge se trouve ainsi déterminé; la faune précitée établit en même temps une concordance bien nette avec les couches du même âge de l’Inde anglaise. 2°. Lutétien supérieur avec N. pengaronensis, Assilina, Alveolina, Orthophragmina, à rapprocher également des couches de l’Inde. 3°. Aquitanien, caractérisé par ses grandes Lépidocyclines. Ce niveau est connu maintenant depuis l’Inde anglaise jusqu’aux Philippines, en passant par l’île de Nias, par Java, par Bornéo, par Célèbes et par l’île de grand Key. Il correspond dans l’Aquitaine aux couches de St. Géours et de Peyrère, — dans l’Italie du Nord, aux couches de Mte. Mos calli, etc. 4°. Burdigalien, avec ses Miogypsina et ses Nephrolepidina, accompagnant partout le niveau précédent

Late Aptian-Albian primitive Radiolitidae (bivalves, hippuritoidea) from Spain and SW France

The late Aptian-Albian radiolitid taxa, Praeradiolites cantabricus (Douvillé) and Praeradiolites ibizanus Astre, from SW France and Spain, are transferred to Eoradiolites. Eoradiolites jumillensis nov. sp. is described from southern Spain, while the so-called “Sphaerulites cantabricus” sensu Toucas (1907) is moved to Praeradiolites and may be of Late Cretaceous age. The Eoradiolites cantabricus group of species is mainly Clansayesian-early Albian in age and possesses an advanced evolutionary status, mainly regarding shell size and cellular structure. Praeradiolites may have been derived from Eoradiolites jumillensis nov. sp. through paedomorphosis while Eoradiolites cantabricus may have been the source for Sphaerulites. Our study shows that the names Sphaerulites and Praeradiolites cannot be applied to pre-Cenomanian Radiolitidae and that Eoradiolites was the foremost genus in Late Aptian-Albian times in terms of species biodiversity. The Eoradiolites cantabricus group is restricted to the northwestern Mediterranean Tethyan margin.Our field investigation in southern Spain have been founded by the Ministerio de Ciencia y Tecnologia of Spain, number of project: REN2001-1067/GLO (Aplicacion de tecnicas del analisis de cuencas sedimentarias en el uso no destructivo del patrimonio natural en al Prebetico oriental. El altiplano de Jumilla-Yecla). At the Université de Provence, we have benefited from the technical assistance of A. Arnoux. Fruitful discussions with L. Villiers (Université de Provence, Marseille)Peer reviewe

Le Barrémien supérieur de Brouzet : partie III : Les rudistes / Henri Douvillé

Note : 19 p.-IV pl. : ill. ; 33 cm. (Mémoires de la Société géologique de France. Paléontologie ; 52). Partie 1 : mémoire no 37 ; partie 2 : mémoire no 51