Please cite this article in press as: Hagdorn, H., Wang, X.F., The pseudoplanktonic crinoid Traumatocrinus from the Late Triassic of Southwest China — Morphology, ontogeny, and taphonomy. Palaeoworld (2015), http://dx.doi.org/10.1016/j.palwor.2015.05.006 ARTICLE IN PRESS +Model PALWOR-306; No. of Pages 18 Available online at www.sciencedirect.com ScienceDirect Palaeoworld xxx (2015) xxx–xxx The pseudoplanktonic crinoid Traumatocrinus from the Late Triassic of Southwest China — Morphology, ontogeny, and taphonomy Hans Hagdorn a,∗ , Xiao-Feng Wang b a Muschelkalkmuseum Ingelfingen, Germany b Wuhan Institute of Geology and Mineral Resources, No. 69 Guanggu Road, Wuchang, Wuhan, Hubei 430205, China Received 28 December 2014; received in revised form 13 March 2015; accepted 18 May 2015 Abstract The morphology of the pseudoplanktonic crinoid Traumatocrinus from the early Late Triassic (Carnian) Xiaowa Formation of Guanling County (South China, Guizhou Province) is described based on articulated and disarticulated material. Juvenile individuals of less than 10 mm crown height with 20 isotomously branching arms prove the encrinid ancestry of the family Traumatocrinidae. However, even the smallest individuals have five large interradials. Endotomous branching commences at crowns of slightly more than 10 mm at the outer arms of the rays. All brachial articulations are ligamentary (granosyzygies). The assignment of the Chinese material to one of the nominal species of Traumatocrinus is still left open. The diagnosis of the genus Traumatocrinus is emended. Traumatocrinus lived attached to driftwood and was widespread across the Palaeo-Tethys. In contrast to its benthic encrinid ancestors, Traumatocrinus fixed its distal column with countless anastomosing radicular cirri to its substrate, preferentially to the ends of the driftwood logs. Depending on the state of the hypothesized mutable collagene tissue, the columns are preserved in straight positions or curved like a rope. Crowns are preserved in star position with radially splayed arms or in lateral bell position with the cup disrupted in interbrachial position. As usual in black shales, the exposed upper sides of the crinoids are in a more or less progressive state of decomposition whereas the embedded lower sides are intact. © 2015 Elsevier B.V. and Nanjing Institute of Geology and Palaeontology, CAS. All rights reserved. Keywords: Crinoidea; Morphology; Ontogeny; Taphonomy; Triassic 1. Introduction The Triassic crinoid Traumatocrinus is spectacular in many respects. Traumatocrinus was the first post-Palaeozoic crinoid that switched from the benthic lifestyle of its encrinid ancestors to pseudoplanktonic floating attached to driftwood. Depend- ing on log size, large numbers of individuals attached to their substrate forming clusters covering more than a hun- dred square meters in black shales of the early Carnian Xiaowa Formation of Southwest China (Guizhou and Yunnan provinces). With column lengths exceeding 10 m, Trauma- tocrinus was larger than any other crinoid before, and it was one of the largest invertebrates throughout the Phanerozoic. ∗ Corresponding author at: Muschelkalkmuseum, Schloss-Str. 11, D-74653 Ingelfingen, Germany. Tel.: +49 7940 59500. E-mail address: encrinus@hagdorn-ingelfingen.de (H. Hagdorn). Traumatocrinus remains have been reported from a vast area throughout the entire Palaeo-Tethys from the Alps to Timor, indicating that it was perfectly adapted to a pseudoplanktonic lifestyle. However, most of the intact individuals attached to complete driftwood logs were excavated in Guizhou and Yunnan provinces. They are exhibited in many museums within and out- side China. In China the esthetic “fossil flower bunches” are sold to hotels or wealthy people to display them like paintings. In situ Traumatocrinus colonies still attached to their driftwood logs are displayed in the Wolonggong Museum of Guanling County. In view of such importance, it is surprising that the his- tory of identification and systematic position of Traumatocrinus among the Crinoidea is connected with many errors and misin- terpretations. In addition, functional morphology remains poorly understood and leaves several questions open. The aim of the present paper is in the first instance to report the state of research on Traumatocrinus and to describe its com- plex morphology in more detail than up to now. Moreover, it http://dx.doi.org/10.1016/j.palwor.2015.05.006 1871-174X/© 2015 Elsevier B.V. and Nanjing Institute of Geology and Palaeontology, CAS. All rights reserved.