Rowe Claire E, Ahyong Shane T, Figueira Will F, Burghardt Ingo, Keable Stephen J
Australian Museum Research Institute, Australian Museum, Darlinghurst, New South Wales, Australia.
School of Biological, Earth & Environmental Sciences, University of New South Wales, Kensington, New South Wales, Australia.
PeerJ. 2025 Jul 18;13:e19669. doi: 10.7717/peerj.19669. eCollection 2025.
Scyphozoans of the genus are notable for their unusual benthic habit of lying upside-down with their exumbrella resting on the substrate and oral arms facing upwards resulting in their common name "upside-down jellyfish". includes species that have been historically confused because of taxonomic ambiguity. Additionally, some species are considered to be invasive, which can have significant economic and environmental consequences by impacting fisheries, tourism, and trophic structures. In temperate southeastern Australia, medusae were first reported in temperate Wallis Lake and Lake Illawarra in 2016, and then Lake Macquarie in 2017, though historically these jellyfish have a more northern tropical distribution in Queensland, eastern Australia. Owing to the invasive potential of , correct species identification is crucial for future management. To address this knowledge gap, this study used genetic comparison through the cytochrome c oxidase subunit I (COI) barcoding gene and morphometric analysis, together with revision of type and topotype material of Gershwin, Zeidler & Davie, 2010, an incompletely known nominal species from Queensland, to investigate the identity of occurring in Lake Macquarie. The morphometric analysis was also used to identify key features that distinguish the Lake Macquarie species from a second species, designated sp.3, that is also expanding its range southwards in eastern Australia, and which may be sympatric in some areas. The results of this study show the species occurring in Lake Macquarie is Bigelow, 1892, originally described from Jamaica and subsequently widely reported from the Western Atlantic and the Indo-West Pacific. Additionally, we demonstrate that , is a junior synonym of . Morphological characters that can be most readily used to distinguish mature specimens of from . sp.3, which has an overlapping distribution on the Australian east coast, are: (1) the number of large appendages on the oral disc, which is much higher in sp.3 (at least 1 but up to 14) a maximum of two in ; (2) the oral arm branching pattern, which is usually alternating for , but a combination of alternating, bifurcating and pinnate for sp.3; (3) the length of the large appendage on the oral arm, which is proportionally longer relative to the bell diameter in .
属的钵水母纲动物以其不寻常的底栖习性而闻名，它们倒置着生活，外伞面 resting on the substrate（此处“resting on the substrate”可能有误，推测为“resting on the substratum”，意为“ resting on the substrate”，意为“附着在基质上”），口腕朝上，因此它们有了“倒立水母”这个俗称。该属包括一些由于分类学上的模糊性而在历史上被混淆的物种。此外，一些物种被认为是入侵物种，这可能会对渔业、旅游业和营养结构产生重大的经济和环境影响。在澳大利亚东南部温带地区，2016年首次在温带的沃利斯湖和伊拉瓦拉湖报道了该属的水母，2017年在麦夸里湖也有发现，不过从历史上看，这些水母在澳大利亚东部昆士兰州的分布更偏热带北部。由于该属具有入侵潜力，正确识别物种对于未来的管理至关重要。为了填补这一知识空白，本研究通过细胞色素c氧化酶亚基I（COI）条形码基因进行遗传比较和形态测量分析，并对2010年Gershwin、Zeidler和Davie描述的一个来自昆士兰州的知之甚少的名义物种的模式标本和原产地模式标本进行修订，以调查在麦夸里湖出现的该属物种的身份。形态测量分析还用于确定区分麦夸里湖物种与另一个也在澳大利亚东部向南扩展分布范围且在某些地区可能同域分布的物种（指定为 sp.3）的关键特征。本研究结果表明，在麦夸里湖出现的物种是1892年的比奇洛水母，最初是从牙买加描述的，随后在西大西洋和印度 - 西太平洋广泛报道。此外，我们证明了 ，是 的次异名。最容易用于区分成熟的 标本与 在澳大利亚东海岸有重叠分布的 sp.3的形态特征是：（1）口盘上大附属物的数量，sp.3的数量要多得多（至少1个但最多14个），而 在 中最多有两个；（2）口腕分支模式， 在 中通常是交替的，而在 sp.3中是交替分支和羽状分支的组合；（3）口腕上大附属物的长度，相对于 在 中相对于钟形直径成比例地更长。
