Middle Ordovician Echinoderms from Northern Illinois and Southern Wisconsin
Middle Ordovician Echinoderms from Northern Illinois and Southern Wisconsin
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来自伊利诺伊州北部和威斯康星州南部的中奥陶世棘皮动物
DOI：
10.1017/s0022336000061734
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发表时间：
1975
影响因子：
1.4
通讯作者：
D. Kolata
中科院分区：
文献类型：
--
作者：
D. Kolata
中奥陶纪普拉特维尔和伊利诺伊州中北部和威斯康星州中南部的下方铅矿群的棘皮动物至少有7个纲，包括Homoiostelea、Cystoidea、Crinoidea、Stelleroidea、Edrioasteroidea、Cyclocystoidea、Echinoidea和可能的Holothuroidea。最丰富和多样的棘皮动物是单环和双环的海百合和海百合，其中杯海百合和雕海百合是最好的代表。本文描述了海百合科13个新种和1个新属：Cremacrinus guttenbergensis，Anocrinus forrestonensis，Isotomocrinus minutus，Carabocrinus oogyi，Dendrocrinus？springeri、Merocrinus britonensis、Cupulocrinus plattevillensis、C. molanderi、罗克顿尾海百合Reteocrinus rocktonensis、R. spinosus、Traskocrinus mahlburgi（n.属（gen.et sp.），Rhaphanocrinus buckleyi、Glyptocrinus charltoni和G.脓疱病本文还描述了菱壳类囊虫的一个新种--杜兰冠囊虫。Bothriocidaris Bothriocidaris Bothriocidaris Bothriocidari n. sp.）和坦氏新裂头绦虫Neobothriocidaris templetoni n.种）这是首次在北美报道，似乎是最早的记录发生。还发现了第三种bothriocidarid的遗骸，其特征是合并的足孔。光镜和扫描电子显微镜保存完好的cyclocystoid标本揭示了一些以前未描述的中央盘和亚边缘环的形态特征，可能会揭示一些光的功能形态。来自苏格兰格文附近Thraive Glen的Upper Drummuck Group海星床的Cupulocrinus gracilis Ramsbottom在这里重新分配到C。德拉姆克山;棘皮动物与丰富多样的动物群相关联，主要由悬浮饲养者组成，主要是strophomenid和orthid腕足动物以及trepostome和隐口苔藓动物。其他常见的种类包括珊瑚、三叶虫、海绵和软体动物。在某些地方，丝状棕色、叶状红色和管形绿色藻类与动物群有关。研究区普拉特维尔（不列颠、沃尔格林和福雷斯顿成员）和下加伦群的石灰岩和白云岩相的碳酸盐岩主要由丰富的贝壳类无脊椎动物组成，这些无脊椎动物作为整体和破碎的、未磨损的、通常有关节的遗骸“漂浮”在高度生物扰动的钙质粉砂岩基质中。碳酸盐沉积物似乎是在一个接近或低于浪基面、高度稳定、开阔的海洋环境中沉积的，其特征是低沉积坡度、良好的循环和低陆源流入。
Echinoderms of the Middle Ordovician Platteville and lower Galena Groups of north-central Illinois and south-central Wisconsin are represented by at least seven classes including the Homoiostelea, Cystoidea, Crinoidea, Stelleroidea, Edrioasteroidea, Cyclocystoidea, Echinoidea, and possibly Holothuroidea. The most abundant and diverse echinoderms are monocyclic and dicyclic inadunate and camerate crinoids, of which the cupulocrinids and glyptocrinids are best represented. Thirteen new species and one new genus of crinoids are described: Cremacrinus guttenbergensis, Anulocrinus forrestonensis, Isotomocrinus minutus, Carabocrinus oogyi, Dendrocrinus? springeri, Merocrinus britonensis, Cupulocrinus plattevillensis, C. molanderi, Reteocrinus rocktonensis, R. spinosus, Traskocrinus mahlburgi (n. gen. et sp.), Rhaphanocrinus buckleyi, Glyptocrinus charltoni, and G. pustulosis. One new species of rhombiferan cystoid, Coronocystis durandensis, is also described. Echinoids of the family Bothriocidaridae (Bothriocidaris solemi n. sp. and Neobothriocidaris templetoni n. sp.) are reported for the first time from North America and appear to be the earliest recorded occurrence. Remains of a third bothriocidarid characterized by coalesced podial pores have also been discovered. Light and scanning electron microscopy of well preserved cyclocystoid specimens reveal a number of previously undescribed morphologic features of the central disc and submarginal ring that may shed some light on their functional morphology. Cupulocrinus gracilis Ramsbottom from the Upper Drummuck Group Starfish Bed at Thraive Glen near Girvan, Scotland, is here reassigned to C. drummuckensis n. sp. Echinoderms are associated with an abundant and diverse fauna consisting largely of suspension feeders, primarily strophomenid and orthid brachiopods and trepostome and cryptostome bryozoans. Other common groups include corals, trilobites, sponges, and mollusks. Filamentous brown, foliose red and siphonaceous green algae are associated with the fauna at some localities. Carbonate rocks of both the limestone and dolostone facies of the Platteville (Briton, Walgreen and Forreston Members) and lower Galene Groups in the study area consist primarily of abundant shelly invertebrates occurring as whole and broken, unabraded, commonly articulated remains “floating” in a calcisiltite matrix that is highly bioturbated. Carbonate sediments appear to have been deposited in a near-to below wave base, highly stable, open marine environment characterized by low depositional slopes, good circulation and low terrigenous influx.