The Rio Grande do Sul Coastal Plain (southern Brazil) is composed of extensive marine and continental deposits related to at least four lagoon-barrier systems of Pleistocene−Holocene age. Part of these deposits is currently submerged and passing through erosion processes by waves. Vertebrate and invertebrate body and trace fossils are constantly exhumed from these deposits and redeposited on the modern beach face. Among them, a total of 253 fragments of crustacean burrows were collected for this study. Two ichnospecies of Ophiomorpha Lundgren, 1891 were recognized (O. nodosa Lundgren, 1891 and O. puerilis Gibert et al., 2006), but most of the materials can only be assigned to the ‘SOT’ group (Spongeliomorpha de Saporta, 1887, Ophiomorpha, and Thalassinoides Ehrenberg, 1944), mainly because of the lack of a pelleted lining. The absence of pellets and, as a consequence, the ichnotaxonomy of these specimens, is related to taphonomical processes (exhumation, reworking, and transportation) that acted during formation of the ex situ assemblage. The paleoenvironmental dynamics and a taphonomical model are presented to demonstrate how these processes affected the trace fossils since their construction, through exhumation until deposition. Neoichnological observations led us to infer larger producers in comparison to the extant ghost shrimp Sergio mirim (Rodrigues, 1971).

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关于巴西南里奥格兰德海岸平原的异地蛇形目和其他洞穴碎片：古生物学和埋葬学评论

南里奥格兰德海岸平原（巴西南部）由广泛的海洋和大陆沉积物组成，这些沉积物与至少四个更新世-全新世时代的泻湖-屏障系统有关。这些沉积物中的一部分目前被淹没并通过波浪侵蚀过程。脊椎动物和无脊椎动物的身体和痕迹化石不断从这些沉积物中挖掘出来，并重新沉积在现代海滩表面。其中，本次研究共收集了253个甲壳类洞穴碎片。两种物种蛇形目Lundgren，1891 年被认可（O. nodosa隆格伦，1891 年和O. puerilisGibert 等人，2006 年），但大多数材料只能分配到“SOT”组（海绵纲德萨波尔塔，1887 年，蛇形目， 和海藻素Ehrenberg, 1944)，主要是因为缺少颗粒衬里。没有颗粒，因此，这些标本的 ichnotaxonomy 与在异地组合形成期间起作用的埋葬过程（挖掘，返工和运输）有关。提出了古环境动力学和埋藏模型，以证明这些过程如何影响自化石形成以来，从挖掘到沉积的过程。与现存的幽灵虾相比，新生态学观察使我们推断出更大的生产者塞尔吉奥·米林（罗德里格斯，1971 年）。