A new species of echinoid , Bothriocidaris maquoketensis, has been discovered in the Cincinnatian (Upper Ordovician) Fort Atkinson Formation, Maquoketa Group, of northeastern Iowa. The new species is characterized by two widely spaced primary perforate tubercles on opposite sides of the peripodia and by numerous paired interambulacral plates. This occurrence extends the geographic and stratigraphic range of Bothriocidaris in North America

Kolata, Dennis R.

Levorson, Calvin O.

Strimple, Harrell L.

University of Northern Iowa

Proceedings of the Iowa Academy of Science Volume 84 Number Article 7 1977 A New Species of Bothriocidaris (Echinoidea) from the Cincinnatian Maquoketa Group of Iowa Dennis R. Kolata University of Iowa Harrell L. Strimple University of Iowa Calvin O. Levorson University of Iowa Let us know how access to this document benefits you Copyright ©1977 Iowa Academy of Science, Inc. Follow this and additional works at: https://scholarworks.uni.edu/pias Recommended Citation Kolata, Dennis R.; Strimple, Harrell L.; and Levorson, Calvin O. (1977) "A New Species of Bothriocidaris (Echinoidea) from the Cincinnatian Maquoketa Group of Iowa," Proceedings of the Iowa Academy of Science, 84(4), 146-149. Available at: https://scholarworks.uni.edu/pias/vol84/iss4/7 This Research is brought to you for free and open access by the Iowa Academy of Science at UNI ScholarWorks. It has been accepted for inclusion in Proceedings of the Iowa Academy of Science by an authorized editor of UNI ScholarWorks. For more information, please contact scholarworks@uni.edu. A New Species of Bothriocidaris (Echinoidea) from the Cincinnatian Maquoketa Group of Iowa DENNIS R. KOLATA 1 , HARRELL L. STRIMPLE2 , and CAL VIN 0. LEVORS0N3 K OLATA , D .R ., STRIMPLE, H.L. and C.0. L EVORSON . A new species of Bothriocidaris (Echinoidea) from the Cincinnati an Maquoketa Group of Iowa, Proc. Iowa Acad, Sci . 84(4): 146- 149 , 1977. A new species of echinoid , Bothriocidaris maquoketensis, has been disco-vered in the Cincinnatian (Upper Ordovician) Fort Atkinson Formation, Maquoketa Group , of northeastern Iowa. The new species is characterized by The bothriocidarid echinoids are a primitive family of sea urchins known only from Ordovician rocks of Europe and North America . At present the famil y consists of three distinctive genera - Bot-hriocidaris, Neobothriocidaris, and a new genus to be described by Kier (in press) from the Bromide Formation of Oklahoma . The three genera are similar in that they are characterized by a small , rigid test that is composed of thick , nonimbricated plates . In addition , they all possess podial pores that open externally in distinct peripodia sur-rounded by a rim on which one or more perforate spine tubercles are developed. They differ markedly with respect to the position of the radial water vessels (internal or within the ambulacral plates) , arrange-ment of ambulacra, position and shape of podial pores , and the de-velopment of interambulacra . The foss il record of the bothriocidarid echinoids is scant , and well -preserved specimens are rare . Two fairly well-preserved specimens representing a new species, Bothriocidaris maquoketensis, have been found in the Cincinnatian (Upper Ordovician) Fort Atkinson Forma-tion, Maquoketa Group , of northeastern Iowa. The occurrence exte nds the geographic and stratigraphic range of Bothriocidaris in North America . On the basis of conodont faunas (Sweet et al. , 1959) , the Fort Atk inson Format ion is considered to be late Edenian in age. If so , it is likely that 8 . maquoketensis n. sp. is approximately equivalent in age to B. parvus Manni! ( 1962) and B. globulus Eichwald ( J 860), both from the Upper Ordovician Yormsi F ,b strata of Estonia. SYSTEMATIC PALEONTOLOGY Class ECHI NOIDEA Leske Subclass PERI SCHOECHI NOID EA M' Coy Order BOTHRIOCIDAROIDA Zittel Family BOTHRI OCIDARIDA E Klem Genus BOTHRIOC IDARIS Eichwald Type species. - Bothriocidaris globulus Eichwald, 1860, p . 654 . Diagnosis.- Bothriocidaridae with ambulacra arranged in two col-umns that terminate adorally in a single nonpori ferous plate and api -cally in a single radi al (ocular), one of which is a madreporite ; one pore pai r per ambulacral plate, pores diverging toward interi or; interam-bulacra in a single column or with paired plates, interambulacra not reaching the peristome; lantern and spines present. Remarks. - Most spec ies of Bothriocidaris are characteri zed by s in g le -co lumn ed interambul acra and thu s di ffe r fro m modern echinoids, which possess two columns of interambul acral plates , and ' Illinois State Geological Survey , Urbana , Illinois 6 1801 2 Department of Geology, University of Iowa, Iowa City, Iowa 52242 3 Box 13, Ricevi lle, Iowa 50460 two widely spaced primary perforate tubercles on opposite sides of the peripodia and by numerous paired interambulacral plates . This occurrence extends the geographic and stratigraphic range of Bothriocidaris in North America. INDEX DESCRIPTORS : Echinoidea , Bothriocidaris maquoketensis, Maquoketa Group , Upper Ordovician , Iowa. from most other Paleozoic spec ies which have numerous pl ates either arranged in several columns or irregul arly arranged. It is evident from the material described here, however, that the interambul acra l columns in Bothriocidaris may consist in part of paired plates . Although the paired plates are suggestive of double-columned interambul acra , the lack of interradial genital plates and the position of orig in of the interambulacra sugges t that B. maquoketensis n. sp. is nothing more than a divergent spec ies of Bothriocidaris. Bothriocidaris maquoketensis Pl. I , fig . 1-8; text fig . I Diagnosis . - A species of Bothriocidaris charac teri zed by two widely spaced perforate tubercles , one on either side of the peripodium; interambulacra that consist of numerous paired pl ates that tend to alternate with a single plate near the ambitus; one to three perforate tubercles on the interambulacral pl ates. Material . - Two specimens, both free from the matrix , were availa-ble for study. The holotype (SUI 42700) is a nearly complete specimen that for the most part has retained its original spherical shape . The test is 9 mm in diameter and is composed of approx imately 135 plates . The paratype (SUI 4270 1) is a somewhat distorted spec imen that was probably about 16 mm in d iameter. Some of the pl ates are disarticul ated and were pushed to the interior or lost during preservation. Both specimens have been abraded and most of the surface detail has been destroyed . The pores and some sutures are fi lled with clear calcite cement. Both specimens are in the reposi tory at the Uni versity of Iowa, Io wa City , Iowa . Description. - The plates of the apical system in the holotype are intact except forone radial that is di splaced slightly below the surface of the test and one or two d isassociated plates at the center. In thi s spec imen the apical system consis ts of fi ve relati ve ly large , th ick , contiguous rad ial plates (text fi g . I B) . The radials are slightly wider than high. One radi al possesses a single , small , round pore situated half way between the center of the plate and the interrad ial suture . The four other radials do not appear to have pores or slits . Surface feat ures have been abraded from all rad ials except one, which possess two elevated perforate tubercles . Eight or nine smaller plates are located wi thin the circlet of radials; the fi ve largest plates are in the interradial position and three or four smaller plates are located at the center of the apical system. The apical system in the paratype is mostly disarticul ated; only two radia ls are intact. One of the radials clearl y possesses two widely spaced pores. There are two closely spaced perforate tubercles on the other radial. In additio n, whe n viewed under xy lol there is an anas-tomose network of dark cal cite, not seen on any other pl ate, near the base of the two tubercles , but it is not clear whether this structure passes through the plate to the interior as would be ex pected if it were the madreporite (text fi g . IC) . If thi s is the madreporite , it is poss ible that the two pores on the remaining radial plate are genital pores . 1Kolata et al.: A New Species of Bothriocidaris (Echinoidea) from the CincinnatiaPublished by UNI ScholarWorks, 1977A NEW SPECIES OF BOTHRIOCIDARIS 147 Figure I. Bothriocidaris maquoketensis n . sp., oral (A) and aboral (B) views of holotype SUI 42700, approx. x 9 . The interambulacra and obvious primary tubercles are stippled . See Plate I , figures 7 and 8. The ambulacra consist of two columns of perforate plates with 12 to 14 plates per column in the smaller spec imen (ho lotype SUI 42700) and 13 to 14 in the larger specimen (paratype SUI 42701 ) . The pl ates are irregularly hexagonal except for the last formed plates at the apical end, which range from trigonal to pentagonal in outline . A plate at the ambitus in the paratype is 3.2 mm wide, 1. 5 mm high , and 0 .9 mm thick . The width-to-height ratio of ambulacra l plates is greater in the larger specimen than in the smaller speci men. The peripodia are round, have a rim that is only slightl y raised above the plate surface, and are generally located at the center of the plate . The pore pairs are arranged obliquely, one above the other, at an angle of about 65° to the long ax is of the plate . The outer pore of a pore pair is more adapical than the inner pore . Small , irregularly shaped calcareous spicules of the tube feet, are still attached to some peripod ia on the paratype. Most ambulacral plates have two elevated , perforate tuber-cles , located on opposite sides of the peripod ia . The peripodia and the tubercles generally lie on the long ax is of the plate. Tubercles at the ambitus of the paratype are commonly 0.5 mm in d iameter. Small nodes and pustules also occur on the ambulacral plates. The interambulacra consist of numerous paired plates . The column is a single pl ate wide adorally, but consists of increasingly more paired plates apically. The paired plates commonly alternate with a single , large, wide plate along the length of the column . At the apical end of the (C) aboral view of paratype SU 142 70 I showing paired interambulacra plates. Position of anastomose network of dark calcite shown at arrow. The interambulacra and the obvious primary tubercles are stippled, approx. x 5. See Plate I , figure 2. colu mn the interambulacra terminate in a single pl ate at the interray suture outside of the circlet of oculars. The ambulacra l columns con-verge adora lly and separate the interambul acra from the peri stome; the proxi mal interambulacral plate is situated between the second and third plates of adjacent ambulacral columns. The interambul acral plates are pentagonal to heptagonal in outline and range from 11 to 16 per column in the paratype and from 8 to 13 in the holotype . At the ambitus in the holotype the plates are higher than wide, but are approx imately equidimensional where a column is two plates wide . In the paratype the interambulacral pl ates are generally wider than high and they are larger than adjacent ambulacral plates . A pl ate at the ambitus in the paratype is 4 mm wide and 2 mm high. One to three elevated , perforate tubercles occur on plates along the midzone in both the holotype and paratype . In the holotype some of the basicoronal plates are disassociated , but it is clear that there were IO imperfora te plates - 5 relatively large radial plates alternating with 5 smaller interradial plates (text fi g . I A). These plates are surrounded by 10 contiguous primord ial ambulacral plates . The radial plates are essentially pentagonal and the adoral edge is broadly rounded. The height and width of the rad ials are approx i-mately the same. The interradials are slender and elongate and are approx imately half the size of the radials. The interradials are partially concealed by the stout radials . The bas icoronal plates surround several 2Proceedings of the Iowa Academy of Science, Vol. 84 [1977], No. 4, Art. 7https://scholarworks.uni.edu/pias/vol84/iss4/7(LL61) 178 "DS ·av:Jy VMOI ":)O~d 8171 3Kolata et al.: A New Species of Bothriocidaris (Echinoidea) from the CincinnatiaPublished by UNI ScholarWorks, 1977A NEW SPECIES OF BOTHRIOCIDARIS 149 undifferentiated peristomial plates. The basicoronal area is not well preserved in the paratype , but elements that are present appear to be very similar to those of the holotype. Several slender spines from 2 to 3 mm long are embedded in the matrix on the surface of the paratype. Remarks. - Species concepts in Bothriocidaris are based largely on the number and distribution of perforate spine tubercles , and on the shape and elevation of the peripodial rim. Seven species are presently known from the Middle and Upper Ordovician of Europe and North America, including Bothriocidaris maquoketensis n. sp. and a species to be described by Keir (in press) from the Bromide Formation of Oklahoma. B. maquoketensis differs from B. parvus Manni) (1962) and B. globulus Eichwald ( 1860) both from the Upper Ordovician (Vormsi F,b) of Estonia and the Bromide species in having only two perforate primary tubercles on the peripodia rather than three or more . The new species is similar to B . pahleni Schmidt ( 1864) from the Middle Ordovician (Joh vi , D,) andB . eichwaldi Manni I (1962) from the Upper Ordovician (Pirgu Stage , F ,c) of Estonia in having only two perforate tubercles on the peripodia; however, in the latter two species the tubercles are much closer to each other, the peripodial rim is higher, and the interambulacra lack perforate primary tubercles. B. maquoketensis is probably most closely related to B. solemi Kolata (1975) from the Champlainian (Middle Ordovician) Grand Detour Formation, Platteville Group, near Dixon, Illinois. B. solemi also is characterized by two primary perforate tubercles on the peripodia and be primary tubercles on the interambulacra , but it differs from B. maquoketensis in having closer peripodial tubercles and numerous secondary perforate tubercles on the ambulacra and interambulacra. None of the other species are known to have paired interambulacral plates as does the new species. Ontogenetic changes in morphology are evident in the two speci-mens of B. maquoketensis. One of the most noticeable changes is the increase in number of interambulacral plates per column, from 8 to 13 in the smaller (diameter of test 9 mm) to 11 to 16 in the larger (diameter of test 16 mm) . The corresponding increase in the number of ambulac-ral plates, however, is only from 12 to 14 to 13 and 14. New interam-bulacral plates appear to have originated along the adradial suture between the oculars and the fourth ambulacral plate . The number of paired interambulacral plates increase apically, apparently as a result of the increasing size of the test and corresponding increase in width of the interambulacra. Plate I 1-8. Bothriocidaris maquoketensis n. sp.; Fort Atkinson Formation, Maquoketa Group, northeastern Iowa: specimens photographed under xylol. I, 2 . Paratype SUI 4270 I, oral and aboral views, respectively, x 4. 3-8 . Holotype SUI 42700, 3 and 5 are side views showing paired interambulacral plates, 4 and 6 are oral and aboral views, respectively, x 5. 7, 8, closeups of oral and aboral surfaces, x I I . Occurence. - Both specimens were collected by Glenn Crossman of Riceville, Iowa, in road fill near exposures of the Fort Atkinson Formation. The associated fossils, including the brachiopods Lepidocyclus laddi Wang , Austine/la whitfle/di (Winchell) and Hypsip-tycha hybrida Wang, and the lithology (argillaceous , fine grained , buff dolomite) strongly suggest that both echinoids came from the Cincinna-tian (Upper Ordovician) Fort Atkinson Formation (bed no. 8 of Parker et al. , 1959) of the Maquoketa Group . The holotype (SUI 42700) was found southeast of Fort Atkinson, Winneshiek Co., Iowa (NW NW NE Sec . 17, T. 96N., R. 9W., Decorah Quad.). Theparatype (SUI 42701) was found southwest of Eldorado, Fayette Co. , Iowa (SW SW Sec. 18, T. 95 N., R. 8 W. , Decorah Quad.). Name. - The specific name refers to the Maquoketa Group, in which the species occurs. ACKNOWLEDGMENTS We are grateful to Porter M. Kier, National Museum of Natural History, Washington, D.C., and Daniel B. Blake, Department of Geology, University of Illinois, Urbana, for their many helpful sugges-tions and comments. Terrence J . Frest, Department of Geology, The University oflowa, Iowa City, reviewed the paper and assisted with the final draft. We also thank the Illinois State Geological Survey and the Department of Geology, University of Illinois , for the use of facilities during the preparation of the manuscript. REFERENCES EICHW ALD, E. 1860. Lethaea Rossica ou Paleontologie de le Russie. 654 p. KIER, P. M. (in press) . Echinoids from the Middle Ordovician Bromide Formation. KOLATA, D.R. 1975. Middle Ordovician echinoderms from northern Illinois and southern Wisconsin. Paleont. Soc . , Mem. 7, 74 p. MANNIL, R. M. 1962. The taxonomy and morphology of Bothriocidaris (Echinoidea). Trudy Inst. Geolog. Akad. Nauk. Eston. SSR. V. 9, P, 143-190. PARKER, M. C., F. H. DORHEIM , and R. B. CAMPBELL. 1959. Resolving discrepancies between surface and subsurface studies of the Maquoketa Formation of northeast Iowa. Proc. Iowa Acad. Sci. v. 66, p. 248-256. SCHMIDT. F. 1864. "Uber einige neue und wenig bekannte Baltisch Siluris-chen Petrefacten. Mem. Acad. Sci. St. Petersburg , v. 21 , ser. 7. SWEET, W. C., C. A. TURCO, E. WARNER, Jr., and L. C. WILKIE. 1959. The American Upper Ordovician Standard; I: Eden conodonts from the Cincinnati region of Ohio and Kentucky. J. Paleont. v. 33, p . 1029-1968. 4Proceedings of the Iowa Academy of Science, Vol. 84 [1977], No. 4, Art. 7https://scholarworks.uni.edu/pias/vol84/iss4/7

A New Species of Bothriocidaris (Echinoidea) from the Cincinnatian Maquoketa Group of Iowa

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A New Species of Bothriocidaris (Echinoidea) from the Cincinnatian Maquoketa Group of Iowa

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