Palaeoecology of Macaronichnus segregatis degiberti: Reconstructing the infaunal lives of the travisiid polychaetes
Palaeoecology of Macaronichnus segregatis degiberti: Reconstructing the infaunal lives of the travisiid polychaetes
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DOI：
10.1016/j.palaeo.2018.12.011
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发表时间：
2019-02-15
影响因子：
3
通讯作者：
Seike, Koji
中科院分区：
文献类型：
--
作者：
Nara, Masakazu;Seike, Koji
Macaronichnus segregatis degiberti是Macaronichnus segregatis的一个相对较大的遗迹亚种，是一个几乎直到轻微弯曲的圆柱形洞穴，水平到倾斜于层面。它被解释为通过选择性的沙子喂养和自由生活的多毛类动物的排泄物形成的pascichietum痕迹化石，例如相对较大的traperidid（以前被归类为opheliid或scalibregmatid）多毛类Travisia。而其他遗迹亚种，即，M. S. segregatis，M. S. lineiformins、M. S. meandriformis和M. S.一般直径2-5 mm，仅出现在前滨沉积物中，M. S. degiberti的直径可达15毫米，并显示出广泛的环境分布，从潮汐通道、潮汐沙坝、潮汐沙脊、潮滩、上至下滨面、生物扰动的桑迪架、架风暴席到架沙脊。M.的核心。S. degiberti主要由富含轻矿物的砂粒组成，由富含轻矿物和富含重矿物的砂的交替层状组成，倾斜于层面排列。另一方面，地幔主要由富含矿物质的重砂组成，具有平滑的轮廓，或两侧均匀分布的裂片。地幔叶和核纹层的形态表明，重复脉冲的沉积物探测和排泄行为的tracemaker。两个或两个以上的洞穴往往出现在邻近，有时交织。由于Travisia是直接发育的，没有任何幼虫阶段，洞穴的聚集可以被解释为反映了穴居人以交配为目的的个体间探索行为。Travisia，又称“臭虫”，分泌挥发性化学物质，可作为性信息素，吸引其他个体在基质中繁殖。因此，一个新的类别的行为学分类的痕迹化石“sequorichnia”（sequor，遵循;和ichnia，痕迹），探索其他个人，在这里提出。这是第一次记录到底栖动物的个体间探索行为。
Macaronichnus segregatis degiberti, a relatively large ichnosubspecies of Macaronichnus segregatis, is an almost straight to gently curved, cylindrical, fossilized burrow, oriented horizontal to oblique to the bedding plane. It is interpreted as a pascichnial trace fossil formed through selective sand feeding and excretion of a free-living polychaete, such as a relatively large travisiid (formerly classified as opheliid or scalibregmatid) polychaete Travisia. While the other ichnosubspecies, i.e., M. s. segregatis, M. s. lineiformins, M. s. meandriformis, and M. s. spiriformis, are commonly 2-5 mm in diameter and occur exclusively in foreshore deposits, M. s. degiberti attains a diameter of up to 15 mm and shows wide environmental distribution, ranging from tidal channels, tidal sand bars, tidal sandridges, tidal flats, upper to lower shorefaces, bioturbated sandy shelves, shelf storm-sheets, to shelf sand ridges. The core of M. s. degiberti, consisting mainly of light mineral-rich sand grains, is composed of alternating lamellae of light mineral-rich and heavy mineral-rich sands, arranged oblique to the bedding plane. On the other hand, the mantle, composed mainly of heavy mineral-rich sands, has a smooth outline, or evenly spaced lobes flanked on both sides. The morphology of the mantle lobes and core lamellae suggests repeated pulses of sediment probing and excreting behaviour of the tracemaker. Two or more burrows of this ichnosubspecies tend to occur adjacently, sometimes intertwining. As Travisia develops directly, lacking any planktic larval stages, aggregations of the burrows can be interpreted to reflect the burrowers' interindividual exploratory behaviour with the aim of copulation. Travisia, also known as a "stink worm", secretes volatile chemical substances that might act as sex pheromones to attract other individuals for reproduction within the substrate. Therefore, a new category of ethological classification of trace fossils "sequorichnia" (sequor, follow; and ichnia, traces), for exploration of other individuals, is proposed here. This is the first record of interindividual exploratory behaviour of infaunae.