Stratigraphic Distribution of Species of the Megaspore Genus Minerisporites in North America GEOLOGICAL SURVEY PROFESSIONAL PAPER 743-E Stratigraphic Distribution of Species of the Megaspore Genus Minerisporites in North America By ROBERT H. TSCHUDY CONTRIBUTIONS TO PALEONTOLOGY GEOLOGICAL SURVEY PROFESSIONAL PAPER 743-E Taxonomy, stratigraphic ranges, and facies significance of Minerisporites megaspores UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON: 1976 UNITED STATES DEPARTMENT OF THE INTERIOR THOMAS S. KLEPPE, Secretary GEOLOGICAL SURVEY V. E. McKelvey, Director Tschudy, Robert H. Stratigraphic distribution of species of the megaspore genus Minerisporites in North America. (Contributions to Paleontology) (Geological Survey Professional Paper 743-E) Bibliography: p. Includes index. Supt. of Docs. no.: I 19.16:743-E 1. Minerisporites. 2. Paleobotany-Cretaceous. 3. Paleobotany-Paleocene. 4. Paleobotany-North America. I. Title. II. Series. III. Series: United States Geological Survey Professional Paper 743-E. QE996.T7 560' .13 76-608080 For sale by the Superintendent of Documents, U.S. Government Printing Office Washington, D.C. 20402 Stock Number 024-001-02892-1 CONTENTS Page Page Abstract ............................................................................................... EI Systematics-Continued New species of Minerisporites............................................................ I Genus Minerisporites-Continued Stratigraphic distribution................................................................... I Minerisporites succrassulus, n. sp ....................................... E7 Significance of megaspores................................................................. 3 Minerisporites pseudorichardsonii..................................... 7 Facies representation........................................................................... 4 M inerisporites sp. A. .. .. ... .. .. ....... .......... .. ... .. .. ... .. .. 7 Systematics.......................................................................................... 5 Minerisporites sp. B............................................................. 8 Genus Minerisporites .................................................................. 5 M inerisporites sp. C. ........ .. ...... .. ....... .. .. .. ..... .. 8 Minerisporite~ mirabilis ....................................................... 5 Methods............................................................................................... 8 Minerisporites glossoferus, n. comb .................................... 6 Literature cited.................................................................................... 9 Minerispoirtes dissimilis, n. sp ............................................ 6 Index .................................................................................................... II ILLUSTRATIONS [Plates follow index] PLATE I. Minerisporites mirabilis and Minerisporites glossojerus. 2. Minerisporites dissimilis. 3. Minerisporites succrassulus. 4. Minerisporites pseudorichardsonii, M. sp. A, M. sp. B, and M. sp. C. Pa~e FIGURE I. Diagram showing stratigraphic distribution of species of Minerisporites reported from North America, including Greenland···················:························ .. ·············· E2 TABLES Page TABLE 1. Species of Minerisporites reported from localities outside of North America ........... E-3 2. Important megaspore assemblages.............................................................................. 4 3. Fossil megaspore localities.......................................................................................... 8 III CONTRIBUTIONS TO PALEONTOLOGY STRATIGRAPHIC DISTRIBUTION OF SPECIES OF THE MEGASPORE GENUS MINERISPORITES IN NORTH AMERICA By RoBERT H. TscHUDY ABSTRACT STRATIGRAPHIC DISTRIBUTION Five species of megaspores assignable to the genus M inerisporites were The stratigraphic distribution of all species of found in samples from the Rocky Mountain region of the United States. One of these species had been reported previously from Alberta, Canada, Minerisporites reported from North America is shown in and one from Montana. Of the three species previously unreported from figure 1. North America, one is a new combination, and two are proposed as new M inerisporites mirabilis (al. Selaginellites mirabilis), species. These megaspores range in age from Albian to Paleocene. The the type of the genus, was reported by Miner (1935) from stratigraphic ranges of all species of the genus reported from North the Paleocene of Montana. I found specimens that I America are also provided. A discussion of the significance of megaspores and their facies representation is presented. consider to be conspecific with M inerisporites mirabilis in the Paleocene of Wyoming. Hall (1963) reported the presence of M. mirabilis in the Dakota Formation NEW SPECIES OF MINERISPORITES (Cenomanian) of Iowa, Hall and Peake (1968) reportedM. Two new megaspore species assignable. to the genus mirabilis in the Windrow Formation of Minnesota M inerisporites were found in Paleocene and Cretaceous (Cenomanian), and Agasie (1969) found specimens that he rocks of the Rocky Mountain region of the United States. assigned to M. mirabilis in the Dakota Formation A third species, previously unreported from North (Cenomanian) of Arizona. The specimen figured by America, was found in Paleocene rocks of Montana. This Agasie is probably a specimen assignable toM. dissimilis, species, previously reported from the Paleocene of the n. sp., as herein proposed. Hall's specimen may belong to Netherlands by Dijkstra ( 1961) as Triletes mirabilis forma the same species, but his figure, photographed by reflected glossoferus and later transferred to the genus light, does not show the detail necessary to allow one to be M inerisporites by Potonie' ( 1966), is herein designated as a sure of such a designation. The specimen figured by Hall new combination-Minerisporites glossojerus. These and Peake is not conspecific with M. mirabilis. three species are described and illustrated in the present Elsik (Stover and others, 1966) reported a form similar to report. Minerisporites mirabilis from the upper part of the A fourth species, which I consider to be conspecific with Paleocene (or lower Eocene) of Texas. He named this fossil Minerisporites mirabilis (Miner) Pot. and which was Minerisporites mirabiloides. Elsik proposed this species previously reported by Miner (1935) from Montana, was on the basis of five specimens, none of which appears to be also found, as were specimens of M inerisporites pseudo­ complete (and unbroken). richardsonii1 Gunther and Hills and of three unnamed Miner (1932) described the species Minerisporites new species. borealis under the genus Selaginellites borealis from the Upper Cretaceous rocks of Greenland. Singh (1964, 1971) The discovery of numerous specimens of three species found three species of Minerisporites from the Albian of new to North America of one megaspore genus was some­ Canada-M. macroreticulatus, M. marginatus, and M. what surprising in view of the apparent rarity of venustus. The species M. macroreticulatus, and M. venu­ megaspores suggested by the scarce reports in the stus were new;M.marginatus had previously been reported literature. Previous to the present work only 11 species of from Upper Jurassic and Lower Cretaceous localities in Minerisporites had been reported from North America. Europe and Australia. (See table I.) That this apparent rarity is probably more illusory than The work of Gunther and Hills (1972 is particularly true will be discussed in the following section. significant because they found seven species of Miner­ isporites in the Brazeau Formation of Alberta, Canada. •Original spelling pseudonchardsoni. See recommendation He, International code of This formation ranges in age from middle Campanian botanical nomenclature, p. 61 (Lanjouw and others, 1966). through middle Maestrichtian. Two of the species, M. El E2 CONTRIBUTIONS TO PALEONTOLOGY (VVV'v Hall and Miner Miner Peake Hall Agasie Elsik2 (1932) Singh (1964, 1971) Gunther and Hills (1972) (1935) (1968) (1963) (1969) (1966) This work ·= Green· Alberta Alberta c.·- Montana Minne- Iowa Arizona Texas o E land ·;:; ~ sota ~ > :;,- "0 0 "QCI> e Q) c. Q) Fort Wilcox .... 0 c. <0·- Q)u Union Group E:::: 0 Wyoming Montana 't; E Q) Fm. w iii 0.. @ @~ ~ 65 ~n~~~n;~~1t0~~~~~r~~~ f-.-- l£!!!:..J Q; a. MAESTRICHTIAN a. :;) c. f- 0 .. ·;:; 70 Q) ro ~ "0 "0 .....E ·- 0 :::E u. ~ e ~ e 1-:;,ro ? Q) N ro a; 00 ~ ~ 0 75 ? ...J ~ Upper CAMPANIAN 1-, ~ Creta- Cl) :;, ceous 0 Q) ~ Q) Montana 80 u a; a. a. :::> Eagle- Sandstone SANTONIAN Wyoming 85 sp. A CONIACIAN Niobrara Formation TURONIAN - 90 CENOMANIAN ~ @ @ Wmdrow Dakota Formation For"lation (J) ~ sp.B sp. C 95 ALBIAN Nebraska Fall A over a; I I Ss. eauivalent a. a. :::> EXPLANATION Cl) Minerisporites mirabilis M. pseudorichardsonii M. mirabiloides :;, @ 0 Q) 1- u M. borealis M. delicatus @ M. dissimi/is ~ ~ ~ Q) Q) u =o M. macroreticulatus -M. corrugatosus -M. succrassulus a; "0 w e '& ~ ~ 0 ~ M. marginatus M. irregularis M. g/ossoferus ...J e ~ ~ ~ f- -~ M. venustus M. deltoides ~ e ~ 1 From Obradovich and Cobban (1975). 0 1 ...J In Stover, Elsik, and Fairchild (1966) . 3 Not to scale below 95 m.y. FIGURE I.-Stratigraphic distribution of species of Minerisporites reported from North America, including Greenland. borealis and M. marginatus, had been reported previously. In addition to the species Minerisporites mirabilis They considered