Thuy Ben, Gale Andy, Numberger-Thuy Lea
Department of Palaeontology, Natural History Museum Luxembourg, Luxembourg City, Luxembourg.
School of Earth & Environmental Sciences, University of Portsmouth, Portsmouth, UK.
PeerJ. 2019 Nov 13;7:e8008. doi: 10.7717/peerj.8008. eCollection 2019.
The genus , which ranks among the most extraordinary of modern brittle stars, is the type genus of the recently resurrected family Astrophiuridae within the order Ophiurida. On account of its absurdly enlarged and strongly modified lateral arm plates, bears a closer resemblance to a pentagonal starfish than to a typical ophiuroid. Although molecular evidence suggests an ancient origin of the Astrophiuridae, dating back at least to the Early Jurassic, not a single fossil astrophiurid has been reported so far. Here, we describe dissociated lateral arm plates from the Campanian of Cringleford near Norwich, UK, and the Maastrichtian of Rügen, Germany (both Upper Cretaceous) with unambiguous astrophiurid affinities and assign these to a new species, . This represents the first fossil record of the family. In addition, the Rügen material included lateral arm plates that superficially resemble those of sp. nov. but differ in having spine articulations that are typical of the ophionereidoid family Amphilimnidae. We assign these plates to a new genus and species, , an extinct amphilimnid with morphological modifications similar to those of , and thus representing a remarkable case of parallel evolution amongst brittle stars looking like starfish.
该属是现代蛇尾纲中最奇特的属之一，是最近复活的蛇尾目 Astrophiuridae 科的模式属。由于其侧向腕板异常增大且强烈变形，它与五角海星的相似性比与典型蛇尾类的相似性更高。尽管分子证据表明 Astrophiuridae 起源古老，至少可追溯到早侏罗世，但迄今为止尚未报道过任何化石 Astrophiuridae。在此，我们描述了来自英国诺里奇附近克林格尔福德坎帕阶以及德国吕根马斯特里赫特阶（均为上白垩统）的离散侧向腕板，它们具有明确无误的 Astrophiuridae 亲缘关系，并将其归为一个新物种。这代表了该科的首个化石记录。此外，吕根的材料包括侧向腕板，其表面类似于新物种的腕板，但不同之处在于具有蛇尾类 Amphilimnidae 科典型的棘关节。我们将这些腕板归为一个新属和新物种，这是一种已灭绝的 Amphilimnidae，其形态修饰与相似，因此代表了在看似海星的蛇尾类中平行进化的一个显著案例。
