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Draconisella mortoni sp. nov., a Mizzia-like Dasycladalean alga from the Lower Cretaceous of Oman

Bruno R.C. Granier and Alexandre Lethiers

Plain Language Abstract

The Order Dasycladales, which consists of "geant" unicellular green algae, spans most of the Phanerozoic times. Its representatives display few thallus shapes: stick-, club-, bowl- or umbel-shaped, or "string of beads". This last morphology corresponds to articulated forms known from the modern Family Dasycladaceae as well as from the extinct families Diploporaceae and Triploporellaceae. On the basis of loose articles we reconstruct here a new Early Cretaceous species and we compare it to Permian and Late Jurassic forms.

Resumen en Español

Draconisella mortoni sp. nov., un alga del grupo Dasycladales y tipo Mizzia del Cretácico Inferior de Omán

El estudio de la asociación de microfósiles del Hauteriviense al Barremiense Inferior en Omán nos llevó a identificar una nueva alga Triploporellaceae. Esta especie se asemeja a alguna Mizzia Schubert, 1909 del Pérmico. Se compara con este género, así como con el género Draconisella Granier and Michaud, 1989 del Jurásico, ambos referidos a la Tribu Mizziineae. Mizzia tiene quistes supuestamente situados dentro del eje principal y Draconisella tiene quistes supuestamente localizados dentro de los laterales, por lo que la nueva especie se atribuye a este último género. Existen muy pocos registros de microfósiles del intervalo Hauteriviense, y esta nueva alga del grupo Dasycladales puede resultar ser un buen marcador en ambientes de carbonatos de aguas someras.

Palabras clave: alga verde fósil; Triploporellaceae; nueva especie; Cretácico; Hauteriviense-Barremiense; Lekhwair

Traducción: Enrique Peñalver (Sociedad Española de Paleontología)

Résumé en Français

Draconisella mortoni sp. nov., une algue Dasycladale du Crétacé inférieur d'Oman ressemblant à une Mizzia

L'étude d'une association de microfossiles provenant de couches d'âge Hauterivien à Barrémien inférieur en Oman nous a conduit à identifier une algue Triploporellacée nouvelle. Cette espèce ressemble à quelques Mizzia Schubert, 1909. Elle est comparée à ce dernier genre du Permien, ainsi qu'au genre Draconisella Granier & Michaud, 1989, du Jurassique, soit deux genres appartenant à la Tribu des Mizziineae. Mizzia étant endosporée (avec des cystes supposément localisés dans l'axe principal) et Draconisella cladosporée (avec des cystes supposément localisés dans les latérales), la nouvelle espèce est attribuée au dernier des deux genres. Il existe très peu de documentation concernant les microfossiles de l'intervalle Hauterivien et cette nouvelle algue Dasycladale pourrait s'avérer être un bon marqueur dans des environnements calcaires d'eaux peu profondes.

Mots-clés : algue verte fossile ; Triploporellacée ; nouveau taxon ; Crétacé ; Hauterivien-Barrémien ; Lekhwair

Translator: Author

Deutsche Zusammenfassung

Draconisella mortoni sp. nov., eine Mizzia-ähnliche dasycladaleane Alge aus der Unteren Kreide Omans

Die Untersuchung einer Assemblage von Mikrofossilien aus Strata des Hauteriviums bis unteren Barremiums aus dem Oman führte zur Identifikation einer neuen triploporellaceanen Alge. Diese Art ist manchen der permischen Mizzia Schubert, 1909 ähnlich. Der neue Fund wird mit letzterer verglichen, ebenso wie mit der jurassischen Draconisella Granier und Michaud 1989, die beide dem Tribus Mizziineae zugeordnet werden. Da Mizzia endosporatisch ist (mit Cysten, die mutmaßlich innerhalb der Hauptachse liegen) und Draconisella cladosporatisch ist (mit Cysten, die mutmaßlich innerhalb der Lateralen liegen) wird die neue Art letzterer Gattung zugeschrieben. Es gibt relativ wenige Nachweise von Mikrofossilien aus dem Hauterivium-Intervall und diese neue dasycladaleane Alge mag sich als guter Marker für Flachwasserkarbonate erweisen.

Schlüsselwörter: fossile Grünalgen; Triploporellaceae; neue Art; Kreide; Hauterivium-Barremium; Lekhwair

Translator: Eva Gebauer

Arabic

743 arab

Translator: Ashraf M.T. Elewa

 

 

author1Bruno R.C. Granier. Dépt. STU, Fac. Sci. Tech., UBO, 6 avenue Le Gorgeu, CS 93837, 29238 Brest cedex 3, France. This email address is being protected from spambots. You need JavaScript enabled to view it.;
and Department of Ecology and Evolutionary Biology, The University of Kansas, 1200 Sunnyside Avenue, Lawrence, Kansas 66045 USA. This email address is being protected from spambots. You need JavaScript enabled to view it.

Since 2004, Bruno Granier is a full Professor and the Chairperson in Paleontology and Sedimentology at the University of Western Brittany - UBO, Brest (France). He is also an Adjunct Research Associate with the Department of Ecology and Evolutionary Biology at the University of Kansas in Lawrence (U.S.A.) since 2007, a "Pesquisador Associado" with the UNESPetro at the "Centro de Geociências Aplicadas ao Petróleo" of the "Universidade Estadual Paulista" in Rio Claro – SP (Brazil) since 2011, and an Adjunct Researcher at the Faculty of Sciences II – Fanar Campus of the Lebanese University in Beirut (Lebanon) since 2013. Bruno holds a B.Sc. in Sedimentary Geology (1981) from P. Sabatier University, Toulouse (France), a M.Sc. in Geodynamics (1983), a Ph.D. in Stratigraphy (1987), as well as a D.Sc. (Habilitation) in Earth Sciences (2003) from Sorbonne University – UPMC, Paris (France). Before joining academe, he worked over a decade and a half for the oil industry. In 1991, he joined Total as Senior Carbonate Sedimentologist at its Scientific and Technical Research Centre in Saint-Rémy-lès-Chevreuse (France). In 1995, he was seconded to ADMA-OPCO in Abu Dhabi (United Arab Emirates), as a Petrography Expert. In 2001 he was back in Paris – La Défense with Total in the reservoir division. Bruno has authored or co-authored tens of technical reports and some 120 research papers – more than half of them, probably, deals with fossil algae.

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author2Alexandre Lethiers. ISTeP - UMR 7193, UPMC - Campus Jussieu, Tour 56-66, 5e étage, Bureau 510 - Case courrier 117, 4 place Jussieu, 75005 Paris, France. This email address is being protected from spambots. You need JavaScript enabled to view it.

Alexandre Lethiers is a fulltime scientific draughtsman at the "Institute of Earth Sciences of Paris" and at the "Research Centre on paleodiversity and Paleoenvironments" of Sorbonne University – UPMC, Paris (France). There, since 2001, in addition to regular scientific or technical drawings for research or teaching, he makes small 3D figures and short 3D animation movies. Alexandre is willing to develop this sort of graphic design as a practical tool for scientific research and science popularization. He has coauthored some scientific papers, mostly in the field of micropaleontology, among which publications on the enigmatic Gilianellids.

 

 

FIGURE 1. 1, Location map and 2, log of the Wadi Al Fayn section (by courtesy of Dujoncquoy, 2011). Star: Type-level of Draconisella mortoni sp. nov., 1) Wadi Nakhr (23°10'26.7"N 57°12'00.4"E), 2) Wadi Kamah (23°06'55.7"N 57°33'07.3"E), 3) Wadi Mu Aydin (23°04'40.1"N 57°29'39.3"E), 4) Wadi Tanuf (22°58'35.3"N 57°40'05.0"E), and 5) Wadi Al Fayn (23°04'39.63"N 57°47'12.55"E). Color code for the main facies: marls and mudstones in blue, bioclastic wackestones in green, oolitic grainstones in yellow, bioclastic and oolitic grainstones in orange, rudist or oncoid floatstones in pink or red.

 figure1

FIGURE 2. Microfossils, “calcareous” algae and foraminifera. 1-2, Deloffrella hauteriviana (Masse, 1999, non 1976): 1, subaxial and oblique sections, Wadi Kamah, sample no. 7 (= Granier, 2013, figure 2.13), 2, subaxial sections,Wadi Mu Aydin, sample no. base-1 (= Granier, 2013, figure 2.3); 3-4, Holosporella sugdeni (Elliott, 1957) Granier, 2017, obliques sections, Wadi Kamah, sample no. 33bis; 5, Praechrysalidina infracretacea Luperto Sinni, 1979, axial section, Wadi Nakhr, sample no. 3; 6-8,Falsolikanella danilovae (Radoičić ex Barattolo, 1978), Wadi Tanuf: 6, oblique section, sample no. 30, 7, subtransverse section, sample no. 54, 8, oblique section, sample no. 31; 9-10, Mayncina sp., Wadi-Kamah: 9, tangential oblique section, sample no. 35, 10, oblique section, sample no. 16; 11-12, Choffatella decipiens Schlumberger, 1905, Wadi Kamah: 11, oblique section, sample no. 34, 12, subaxial section, sample no. 14; 13-16, Coscinoconus sp., Wadi Al Fayn, oblique sections, sample no. 33; 17, Epistomina sp., subaxial section, Wadi Kamah, sample no. 34. Scale bar (for all photos) equals 250 µm.

figure2 

FIGURE 3. Draconisella mortoni sp. nov.: 1-3, Wadi Mu Aydin, sample “base”; 4, holotype, Wadi Al Fayn, sample no. 31; 5-13, Wadi Kamah; 5-6, sample no. 13; 7-9, sample no. 14; 10, sample 31; 11-12, sample no. 32. 1, 4, 9 and 11 are subaxial sections (the main axis is the open pore on the lower side); 7 and 10 are tangential sections (they do not reach the main axis); 2-3, 5-6, 8 and 12 are oblique sections. Scale bar (for all photos) equals 100 µm.

 figure3

FIGURE 4. Mizzia velebitana Schubert, 1909: 1, three articles partly encrusted by bryozoans and still connected, sample no. 692, Collection J. von Pia, “New Mexico, SW of Carlsbad”; 2-4, sample no. CXIV, “Mizziendolomit, Oberstes Karbon. Paklenica, Velebit Geb., Dalmatien. Coll. Schubert”. 2, tangential section of an article, thin section CXIV-1 (Pia, 1920, plate I, figure 13); 3, transverse section of an article, thin section CXIV-3 (Pia, 1920, plate I, figure 21); 4, axial section of an article, neotype herein defined, thin section CXIV-3 (Pia, 1920, plate I, figure 20). Photo 1: Scale bar equals 500 µm; photos 2-4: Scale bar equals 250 µm.

 figure4

FIGURE 5. Draconisella genoti Granier and Michaud, 1989: 1, deep tangential section of an article (= Granier and Michaud, 1989, plate 1, figure 2); 2, deep tangential section of an article (= Granier and Michaud, 1989, plate 1, figure 3); 3-10, deep tangential sections of loose articles; 11, holotype, oblique section of an article with axial cavity visible (= Granier and Michaud, 1989, plate 1, figure 5); 12, deep tangential section section of an article (= Granier and Michaud, 1989, plate 1, figure 6); 1-4, sample no. MX 84 57; 5-6, sample no. MX 84 63; 7-9, sample no. MX 85 495; 10-12, sample no. MX 85 371. Scale bar (for all photos) equals 250 µm.

 figure5

FIGURE 6. 3D “Blender” model for Mizzia-like alga. The main axis is regularly inflated and the laterals are thin in their proximal part. Click on image to run or download animation.

fig6 

 

FIGURE 7. 3D “Blender” model for Draconisella-like alga. The main axis is rather thin, and the laterals are inflated in their proximal part. Click on image to run or download animation.

fig7 

 

FIGURE 8. Rajkaella iailaensis Maslov ex Dragastan and Bucur, 1988, non 1965. 1-2 and 4-6, various oblique to tangential oblique sections through a verticil; 5, tangential section of a lateral at its distal end, through the secondary laterals. 1-3, Berriasian, Corbières (France), Collection Jaffrezo; 4-6, Berriasian, French Jura (France). R1: primary lateral; R2: secondary laterals. Scale bar (for all photos) equals 250 µm.

 figure8

FIGURE 9. The five morphotypes of living Dasycladalean thalli. 1, cylindrical thallus (Batophora oerstedi Agardh, 1854, excerpt from Berger, 2006, Fig. 15); 2, claviform, club-shaped thallus (Bornetella oligospora Solms-Laubach, 1893, excerpt from Berger, 2006, Fig. 33); 3-4, articulated, moniliform thalli, branched (Cymopolia barbata Lamouroux, 1816, excerpt from Berger, 2006, Fig. 64) and not (Cymopolia vanbosseae Solms-Laubach, 1893, excerpt from Berger, 2006, Fig. 72); 5, sphaerical, ball-shaped thallus (Bornetella sphaerica (Zanardini, 1878), excerpt from Berger, 2006, Fig. 43); 6-7, umbelliform thalli (6: Acetabularia kilneri Agardh, 1886, excerpt from Berger, 2006, Fig. 166; 7: Acetabularia schenckii Möbius, 1899, excerpt from Berger, 2006, Fig. 107). Scale bars 1-2 equals 2.5 mm, 3 equals 10 mm, 4-5 equals 1 mm, 6-7 equals 5 mm.

 figure9

FIGURE 10. 1, the original interpretation of Koptedagaria iailaensis Maslov, 1965, nom. nud., which has proved to be wrong (Granier, 1990); 2, the inarticulate-sphaerical hypothetical reconstruction of the new Omani alga, which is not sustainable; 3, the revised interpretation of Rajkaella iailaensis Maslov ex Dragastan and Bucur, 1988, non 1965, with a large cylindrical thallus bearing verticils of rather large laterals (as documented in Figure 8); 4, the articulate-moniliform reconstruction of Draconisella mortoni sp. nov., which is finally adopted in this study.

figure10 

 

TABLE 1. Measurements of the two Draconisella species . LA: length / thickness of an article; D: external diameter / width of an article; d: internal diameter / diameter of the main axis; l: maximum length of the primary pores; p: maximum width of the primary pores (pp: proximal; pd: distal); n: number of whorls per article; w: number of pores per verticil.

Species
Measurements
Draconisella genoti
Granier and Michaud, 1989
Draconisella mortoni sp. nov.
LA down to 0.40 down to 0.30 mm
D up to 1.45 mm up to 0.55 mm
LA/D c. 50% c. 80%
d 0.30 mm (only 1 value) up to 0.10 mm
d/D 25% (only 1 value) 15 to 25 %
l 0.70 mm 0.18 mm
pp 0.04 mm 0.05 mm
pd 0.42 mm 0.14 mm
n 3 4 (? 5)
w ? ~12 6-7 (? 8)