700 JOURNAL OF PALEONTOLOGY, V. 64, NO. 5, 1990 --, B. D. PRATI, AND A. J. ROWELL. 1989. Early Cambrian reefs, Holyoake Range, Antarctica. New Zealand Journal of Geology and reef complexes, and associated lithofacies of the Shackleton Lime­ Geophysics, 31:397-404. stone, Transantarctic Mountains. Sedimentology, 36:341-362. Sowv'Ev, I. A., AND G. E. GRIKUROV. 1979. Novie dannie o ras­ --, AND A. J. ROWELL. In press. The pre-Devonian Palaeozoic elas­ prostranenii Kembriyskikh trilobitov v khrebtakh Ardzhentina i She­ tics of the central Transantarctic Mountains: stratigraphy and depo­ klton [New data on the spread of Cambrian trilobites in the Argentina sitional setting. In M. R. A. Thomson, J. W. Crame, and J. W. Thom­ and Shackleton Mountains]. Antarktika, 18:54-73. son (eds.), Geologic Evolution of Antarctica. Cambridge University TATE, R. 1892. The Cambrian fossils ofSouth Australia. Transactions Press, Cambridge. and Proceedings of the Royal Society of South Australia, 15:183- ROWELL, A. J., K. R. EvANs, AND M. N. REES. 1989. Fauna of the 189. Shackleton Limestone. Antarctic Journal of the United States, 1988 WRONA, R. 1987. Cambrian microfossil Hadimopanel/a Gedik from Review, 23(5):13-14. glacial erratics in West Antarctica. Palaeontological Polonica, 49:37- --, AND M. N. REES. 1989. Early Palaeozoic history of the upper 48. Beardmore Glacier area: implications for a major Antarctic structural Y OCHELSON, E. L. AND E. STUMP. 1977. Discovery of Early Cambrian boundary within the Transantarctic Mountains. Antarctic Science, l: fossils at Taylor Nunatak, Antarctica. Journal of Paleontology, 81: 249-260. 872-875. --, --, R. A. COOPER, AND B. R. PRATI. 1988. Early Paleozoic history of the central Transantarctic Mountains: evidence from the ACCEPTED 19 MARCH 1990 J. Pa/eont., 64(5), I 990, pp. 700-724 Copyright © 1990, The Paleontological Society 0022-3360/90/0064-0700$03.00 A NEW FAMILY OF TREPOSTOME BRYOZOANS FROM THE ORDOVICIAN SIMPSON GROUP OF OKLAHOMA MARCUS M. KEY, JR. Department of Geology, Dickinson College, Carlisle, Pennsylvania 17013 ABsTRAcr-A new family, Bimuroporidae, is proposed for a clade of Ordovician trepostome bryozoans. The family is united by several characteristics, including a zooidal ontogenetic progression from mesozooid to autozooid and an integrate wall structure. Discriminant and cladistic analyses of colonies from the Ordovician Simpson Group outcropping in the Arbuckle Mountains and Criner Hills of south-central Oklahoma permit the recognition of eight species belonging to this family. Four species assigned to the new genus Bimuropora are described: B. dubia (Loeblich), B. pol/aphragmata n. sp., B. conferta (Coryell), and B. winchelli (Ulrich), as well as four species assigned to the genus Champ/ainopora Ross: C. chazyensis (Ross), C. ramuscu/us n. sp., C. pachymura (Loeblich), and C. arbucklensis n. sp. INTRODUCTION 1982) than those in adjacent basins and very few of the eight ECONSTRUCTING the history of life and understanding its ingroup species occur in other basins. The geographic, strati­ R causal evolutionary processes requires phylogenetic clas­ graphic, and phylogenetic relationships of all of these species sifications. Many previous classifications have been largely based are discussed under Systematic Paleontology. on phenetic similarity with no regard to phylogenetic relation­ Description of the Simpson Group bryozoan fauna began with ships. A phylogenetic approach was adopted in this study using Decker and Merritt (I 931) who listed 24 species. Loeblich (1942) cladistic methodology. Traditional bryozoan taxonomic char­ described 31 species, while Merida and Boardman (1967) listed acters were used as well as characters associated with growth four species. Finally, Farmer ( 197 5) described three more species. pattern, such as zooidal arrangement, budding pattern, and zooi­ Five stratigraphic sections were measured in this study (Fig­ dal ontogeny. ures 1 and 2). These sections include the upper three Simpson This study involved the Simpson Group fauna, which is ex­ Group formations (McLish, Tulip Creek, and Bromide). They posed in the Arbuckle Mountains and Criner Hills of south­ collectively represent about 15 million years of deposition dur­ central Oklahoma and in the Wichita Mountains of southwest ing the Middle Ordovician Chazyan, Blackriveran, and Rock­ Oklahoma. Analysis concentrated on exposures in the Arbuckle landian Stages (Figure 3; Ross et al., 1982). The bryozoans Mountains and Criner Hills (Figure 1) where outcrops of the studied in this report were not found in the Joins and Oil Creek Simpson Group have their greatest thicknesses and are relatively Formations. complete. The Simpson Group was deposited during the Middle USNM collection localities are as follows. Section I: 2130A­ Ordovician and consists of five formations: Joins, Oil Creek, F, Tulip Creek Formation; 2130G, H, Bromide Formation; McLish, Tulip Creek, and Bromide. NW¼, NE¼, sec. 16, T5S, RlE, 7.5' Ardmore West and Over­ Deposition occurred in the subsiding Southern Oklahoma brook quadrangles. Section 2: 2132A-Y, Bromide Formation; Aulacogen Basin. During all of Middle Ordovician time, this SE¼, NE¼, sec. 17, T2S, RlW, 7.5' Fox NE quadrangle. Section basin remained a tectonically negative area (Ross, 1976). Thus, 3: 2l 14A-G and 38979, McLish Formation; 2115A-K, Tulip the Simpson Group provides one of the few complete records Creek Formation; 2116A-L and 38971-38978, Bromide For­ of Middle Ordovician deposition on the North America Plat­ mation; S½, SE¼, sec. 24 and NE¼, sec. 25, T2S, RlE, 7.5' form (Cooper, 1956; Ross et al., 1982). Its bryozoans are gen­ Springer quadrangle. Section 4: 2129A-P, McLish Formation; erally older (based on conodont biostratigraphy of Ross et al., 2128A-E, Tulip Creek Formation; 2127A-Q, Bromide For- This content downloaded from 64.9.63.147 on Tue, 25 Aug 2020 18:57:08 UTC All use subject to https://about.jstor.org/terms KEY-NEW FAMILY OF BRYOZOANS 701 mation; NW¼, sec. 27, T3S, R4E, 7.5' Nebo and Troy quad­ rangles. Section 5: 2153A-Z, McLish Formation; 2153AA-FF and 2154A-I, Tulip Creek Formation; 2155A-Z and AA-FF, Bromide Formation; SW¼, sec. 15, TIS, RlE, 7.5' Turner Falls quadrangle. ·1 MATERIALS AND METHODS This study utilized collections of bulk material from the Simp­ son Group collected by R. S. Boardman in 1961 and 1962, by Boardman and G. T. Farmer, Jr. in 1963, and by Boardman and J.E. Merida in 1966. The author collected more material in 1987 to fill in the stratigraphic gaps in these existing collec­ tions. All of this bulk material is housed in the U.S. National Museum of Natural History, Bryozoa Stenolaemata General xArd Collection. 0 4 8 12 ~ Prior to this study, 105 colonies belonging to the ingroup had ~CRINER HILL Kilome1ers been sectioned by Boardman, Farmer, Loeblich, and Merida. To these the author added another 309 colonies, bringing the total number available for study to 414. All thin sections, acetate FIGURE I -Geologic map of the Arbuckle Mountains and Criner Hills peels, and colony remnants are housed in the U.S. National showing locations of measured and sampled stratigraphic sections. Museum of Natural History, Paleozoic Bryozoa Stenolaemate Stippling indicates Simpson Group outcrops. Redrawn from Sprinkle thin section collection. (1982, fig. 77). THICKNESS STRAT. (METERS) UNITS SECTION 1 SECTION 2 SECTION 3 SECTION 4 SECTION 5 0 u ► -------------- )( ------- .. ----­ Q. ;t ------------- ~ > 0 LL :::> ------- < ·------·------ ... < II) -, -- -- --- ---- -- w tr: --------------- ~► N"_-_-_-_-_-_-_-_-_-_-_-_-_- so 0 0 •••••••••••••• ]: :·.:·:·:·.:·:·: ~ '° t2 :-:·:·:-:·:·:·:·:·:·:-:·:·: N~z ____________------- _ a:0 w ------------­ N c •••••••••••••• CD u ------------- ~ ·:·:-:-:-:·:·:·:-:-:-:-:·:· 100 ~ 150 LL w~ w C .. _ .. _ .. _ .. _-_ .. _ .. a: 0 -------------- 111 (.) m_ ,_,_,_,_,_,_,_.·1:1.·1..·1."'L.-L ... c.. .. , .. ,_,_,_,_.,_ Nm:.-.-.·.-.·:.·.-.·:.·:.·:.u ··-·-·-·-·-·-·-· < ,_,_.,_,_,_,_,_., .. ,.,.,.,_,_ 200 ::J ,.,.,., .. ,., .. , .. < -------------- .. 1 .. 1 .. 1. .. 1 .. 1, .. 1, .. ~ ► )( ,:. EXPLANATION 250 ~ __, ffi LIMESTONE ::i; ----------·------·-·· N .:.. (!) •••••••• •••••• :,: c;, ••••••••·••••• ;nm ARGILLACEOUS LIMESTONE 0 ------------- "'< 300 mm SANDY L IMS TONE ~ C N o -:-:-:-:-:-:- LL ..,. u •••••••..••••• u -_-_-________ I [:::::::1 SHALE co------­ a, - - .... - .. - ---------■------V ~ N _J ~ CALCAREOUS SHALE (.) ~ ~ < ------ 350 [:::::::::::) SANDY SHALE 1)-:-:/j SANDSTONE lfi!il~ 400 FIGURE 2-Measured stratigraphic sections showing positions of collections_ See Figure I for locations of sections. This content downloaded from 64.9.63.147 on Tue, 25 Aug 2020 18:57:08 UTC All use subject to https://about.jstor.org/terms 702 JOURNAL OF PALEONTOLOGY, V 64, NO. 5, 1990 that were most complete. An average of 16 colonies (range 13 Sf!G: SERES FORMA~ R to 25) from each of the eight species was measured. The 131 .!!! colonies included type-specimens from previously described !!! .Q ~ ~ ::, i:i ~ "tJ Middle Ordovician species that were found in the Simpson 5 "i Group. Each quantitative character was measured up to l 0 times B I BROMOE !!! 0 I!! 0 E"' I!! per colony, and the qualitative species groupings were then sta­ ~ 0, I!! ~ 0 I!! 0 ::, Q. tistically checked with this separate set of quantitative charac­ ~ .c: E ters. This analysis is described under Discriminant Analysis . E ~ ::, ~ .§ Most of the characters analyzed in this study are traditional ~ .§ Cll -~ t lQ. Cll c:: Q. bryozoan taxonomic characters. There