Revision of the Brachiopod Cyrtina
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BULLETIN DE L’INSTITUT ROYAL DES SCIENCES NATURELLES DE BELGIQUE SCIENCES DE LA TERRE, 75: 53-66, 2005 BULLETIN VAN HET KONINKLIJK BELGISCH INSTITUUT VOOR NATUURWETENSCHAPPEN AARDWETENSCHAPPEN, 75: 53-66, 2005 Revision of the brachiopodCyrtina rigauxi M a illieu x , 1909 and description of a new ambocoeliid genus(Dionacoelia n. gen.) from the Frasnian of southern Belgium by Bernard MOTTEQUIN M ottequin, B., 2005. — Revision of the brachiopod Cyrtina rigauxi the rare and unrecognized speciesCyrtina rigauxi M aillieux, 1909 and description of a new ambocoeliid genusDiona ( coelia n. gen.) from the Frasnian of southern Belgium.Bulletin de M aillieux, 1909a, but also the description of a new l'Institut royal des Sciences naturelles de Belgique, Sciences de la genus and species of the Ambocoeliinae. Terre 75: 53-66, 9 figs., 2 tables, Bruxelles-Brussel, March 31, 2005 - ISSN 0374-6291. History of the study Abstract Cyrtina rigauxi was described by M a i l l i e u x (1909a, pp. 10-11) from material collected within the Frasnian Cyrtina rigauxi M aillieux, 1909 is transferred to the genusAcutatheca “ Schistes à Spirifer pachyrhynchus” at the cemetery Stainbrook, 1945 thus mentioned for the first time in the Frasnian of the Dinant Synclinorium and Roly “M assif’ (Neuville Formation, quarry at Boussu-en-Fagne (southern border of the Dinant Lower Palmatolepis rhenana Zone). M a i l l i e u x (1940, 1941) included Synclinorium) where the species is very rare according to Acutatheca rigauxi in Cyrtina demarlei B o u c h a r d (nomen nudum) him (p. 11). M aillieux’s drawings represent a typical and C. heteroclita (D efrance, 1824). The specimens identified as Martiniopsis (Elivella) rigauxi by M a i l l i e u x (1940, 1941) [= Echino- ‘‘Cyrtina". Considering the imperfections of these, we coelia rigauxi sensu Vandercammen (1956)] do not belong to can reasonably admit that the specimen IRScNB a9575 C. rigauxi M aillieux, 1909. They are redescribed asDionacoelia from the collections of the Royal Belgian Institute of secessus n. gen., n. sp., a species occurring with certainty in the Ermitage Member of the Moulin Liénaux Formation (Palmatolepis Natural Sciences at Brussels bearing the inscription punctata Zone). Cyrtina rigauxi on its oldest label corresponds to the original illustrations. The same year, M a i l l i e u x Key-words: Brachiopods, Spiriferida, Acutatheca, Dionacoelia, Frasnian, Belgium. (1909b, pp. 121-122,136-137) listed it with the indication “rare” in the “Schistes à C. [= Camarophoria ] fo r mosus” and in the “Schistes de la Zone à Résumé Sp. pachyrhynchus” . In 1940 (pp. 15, 18, 26, 41), the same author cited the species as Martiniopsis (Elivella) L’espèce Cyrtina rigauxi M aillieux, 1909 est attribuée au genre rigauxi in the old Belgian Frasnian subdivisions F2e Acutatheca Stainbrook, 1945 dont c’est la première mention dans le (“ Zone à Leiorhynchus formosus”), F2g (“calcaire Frasnien du Synclinorium de Dinant et du “ M assif’ de Roly (Forma stratifié à Stromatopores”), F2i (“Zone à Reticularia tion de Neuville, Zone inférieure àPalmatolepis rhenana). M a i l l i e u x (1940, 1941) a inclus Acutatheca rigauxi dansCyrtina demarlei B o u pachyrhyncha”) and F2ß (“schistes et calcaires de c h a r d (nomen nudum) etC. heteroclita (D efrance, 1824). Les spéci Bovesse” ). This new generic attribution was not accom mens déterminésMartiniopsis (Elivella) rigauxi par M a i l l i e u x (1940, panied by a discussion. 1941 ) [= Echinocoelia rigauxi sensu Vandercammen( 1956)] n ’appar tiennent pas à C.rigauxi M aillieux, 1909. Ils correspondent à l’espèce However, on the basis of handwritten labels ofM a i l Dionacoelia secessus n. gen., n. sp. présente avec certitude au sein du l i e u x dated from 1938, it appears that inM a i l l i e u x Membre de l’Ermitage de la Formation du Moulin Liénaux (Zone à (1940, 1941): 1 - the specimens with a “Cyrtina” ap Palmatolepis punctata). pearance as the specimen IRScNB a9575 are identified as Mots-clefs: Brachiopodes, Spiriferida, Acutatheca, Dionacoelia, Cyrtina demarlei B o u c h a r d and Cyrtina heteroclita Frasnien, Belgique. (Defrance, 1824). As noted byB r i c e (1988, p. 358), C. demarlei B o u c h a r d is a nomen nudum and must be replaced by C. bouchardi B r i c e , 1988.C. rigauxi differs Introduction from C. bouchardi andC. demarlii D a v id s o n , 1864 non B o u c h a r d by its internal characters. 2 - the specimens New collections of Frasnian brachiopods in the Neuville ranged inMartiniopsis (Elivella) rigauxi do not at all Formation in several localities of the southern flank of the correspond to the original figurations ofCyrtina rigauxi. Dinant Synclinorium (Belgium) allowed the revision of Among them, the specimen figured byVandercammen 54 Bernard MOTTEQUIN (1956, pi. 2: 11-13) as Echinocoelia rigauxi is accompa ing these units, see B o u l v a i n et al. (1993, 1999). The nied by a handwritten label ofM a i l l i e u x with the in Ermitage Member of the Moulin Liénaux Fm consists of scription “Martiniopsis (Elivella) rigauxi M aillieux - greyish-greenish shales with some levels of nodules an- Holotype” . dthin beds of argillaceous limestone(Bultynck & In his revision of the Ambocoeliidae from the Devo M ouravieff, 1999, p. 39). It is developed on the southern nian of Belgium, Vandercammen(1956, pp. 30-35) de border of the Dinant Synclinorium; its thickness is com scribed Echinocoelia rigauxi on the basis of specimens prised between 100 m-115 m in the Boussu-en-Fagne - completely different ofM aillieux’s original illustrations Nismes area. The Bieumont Member corresponds to the but corresponding to those identified asMartiniopsis base of the Grands Breux Fm. It includes greyish micritic, (Elivella) rigauxi by M a i l l i e u x (1940, 1941). sometimes bioclastic well-bedded limestones with shaly Restudy of this old material and of newly collected intercalations in its upper part(Bultynck & Dejonghe, specimens shows that: 1 - Cyrtina rigauxi M aillieux, 2002, p. 55). Its thickness is quite variable along the 1909a is a well established species (see the type para southern border of the Dinant Synclinorium: 37 m at graph). It belongs to the genusAcutatheca Stainbrook, Frasnes-lez-Couvin (Coen-Aubert, 1994, p. 22); 23 m 1945. 2 - Martiniopsis (Elivella) rigauxi in M a i l l i e u x to 46 m in the Focant borehole (Boulvain & Coen- (1940, 1941) (non Cyrtina rigauxi M aillieux, 1909a) A u b e r t , 1997, p. 56) and ±20 m at Auffe( C o e n , 1977, [= Echinocoelia rigauxi sensu Vandercammen(1956)] p. 43). The Boussu-en-Fagne Member (Grands Breux corresponds toDionacoelia secessus n. gen., n. sp. Fm) comprises principally greenish shales with calcar To the knowledge of the author, the genusAcutatheca eous nodules and some levels of nodular to bedded lime Stainbrook, 1945 (Spinulinae) was only known with stones. It attains 81 m in its stratotype (railway cut at certainty from two North American species from the Frasnes-lez-Couvin) according toCoen-Aubert, (1994, Lower Palmatolepis rhenana Zone: A. propria S t a i n p. 22), but it is generally reduced in the vicinity of the b r o o k , 1945, the type species from the Independence mudmounds of the Lion Member. The Neuville Fm is shales of Iowa andA. prolifica Cooper & D utro, 1982 made up of nodular limestones and shales with nodules in from the Sly Gap Fm of New Mexico. Day & Dowd the Philippeville Anticlinorium (thickness: 15 m-25 m), (2000) listed the genus in the late Frasnian Redknife but on the southern border of the Dinant Synclinorium Fm (northern part of the Western Canadian Sedimentary where its thickness can attain 110 m in the Han-sur-Lesse Basin). X ia n (in Xian & Jian, 1978) describedA. lata area ( C o e n , 1977, p. 43), it comprises essentially nodular (non vidi) from the undifferentiated Middle Devonian (Province of Guizhou, Southwest China) but this species needs more information accordingT to a l e n t et al. (2001, p. 115). In southern Belgium, the genus occurs in the Dinant Synclinorium Conodont Neuville Fm (Lower P. rhenana Zone; southern flank of Zones South Philippeville the Dinant Synclinorium and Roly “ M assif’) and could Formations be present within the Les Valisettes (UpperP. rhenana linguif. r MATAGNE (F 3B ) <=r- ---- ' tisVALISETTES Zone; Philippeville Anticlinorium) and Lambermont for Upper (F2i) mations (Upper P. rhenana Zone; Vesdre Nappe). ^ ^ /C O IX ^ rhenana NEUVILLE ^ C rickmay (1967, p. 10) founded the subgenusMinu Lower (F2i) -----------:------------?----------- tilla with Acutatheca (Minutilla) layeri C rickmay , 1967 jamieae _______ B o u s s u c as type species, but it has been placed in synonymy with (F 2i) ( Philippeville A lionella C rickmay , 1953 by Carter et al. (1994, Upper L—p L e L ion f (F 2g h ) p. 332). y (F 2h) hassi All measured and/or figured specimens are housed at s ' 7 ^'lftáchenées the Royal Belgian Institute of Natural Sciences at Lower Grands B ieBreux u m o n t (F2crt c /ro ~ \ X Brussels, where they are registered under the numbers ZD 03 ' br-itage, IRScNB a8041, a8046, a9575, al2104 - al2117. C. / \ rC9o F9flY/ LA F O L L E / ' 'Q> punctata / Arche X (F2e , F 2fyfeta,ne J X . 4 (F2d ) 4 “ S a m a r á . X 3 Stratigraphy £ C h a ló n (F2c ) — Upper N ism es (F2a , F2b ) 50 m G e o l o g ic a l c o n t e x t , lithostratigraphical u n it s a n d fatsiovalis BIOSTRATIGRAPHY (Fig.