A new species of the genus Lindaspio Blake & Maciolek, 1992 (Annelida, Spionidae) from a cold seep near Hainan Island, China Author Sui, Jixing https://orcid.org/0000-0003-0792-9093 Laboratory of Marine Organism Taxonomy and Phylogeny, Qingdao Key Laboratory of Marine Biodiversity and Conservation, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China & Laboratory for Marine Biology and Biotechnology, Pilot National Laboratory for Marine Science and Technology (Qingdao), Qingdao, China jxsui@qdio.ac.cn Author Dong, Dong Laboratory of Marine Organism Taxonomy and Phylogeny, Qingdao Key Laboratory of Marine Biodiversity and Conservation, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China & Laboratory for Marine Biology and Biotechnology, Pilot National Laboratory for Marine Science and Technology (Qingdao), Qingdao, China Author Wu, Xuwen Laboratory of Marine Organism Taxonomy and Phylogeny, Qingdao Key Laboratory of Marine Biodiversity and Conservation, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China & Laboratory for Marine Biology and Biotechnology, Pilot National Laboratory for Marine Science and Technology (Qingdao), Qingdao, China Author Li, Xinzheng Laboratory of Marine Organism Taxonomy and Phylogeny, Qingdao Key Laboratory of Marine Biodiversity and Conservation, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China & Laboratory for Marine Biology and Biotechnology, Pilot National Laboratory for Marine Science and Technology (Qingdao), Qingdao, China & University of Chinese Academy of Sciences, Beijing, China text ZooKeys 2023 2023-03-16 1153 105 112 http://dx.doi.org/10.3897/zookeys.1153.101406 journal article http://dx.doi.org/10.3897/zookeys.1153.101406 1313-2970-1153-105 3CA5E635BECD40AA80B3A36E0F3E819 A107B32CE8845017A8B669E7635CB0C4 Lindaspio polybranchiata sp. nov. Figs 2 , 3 , 4 Material examined. Holotype : Complete, Lingshui cold seep cruise, Faxian Dive 252, 1758 m , 17°37'N , 111°03'E , coll. crew of R/V Kexue, 28 May 2021 , MBM 304666. Paratypes : 4 specimens , complete, same collection data as holotype, MBM 304662-MBM 304665 . Non-type : 14 incomplete specimens depositing in one specimen bottle, MBM304661. Description of holotype. Total length 55 mm, maximum width 4 mm, including chaetae. More than 350 crowded chaetigers. Color pale in alcohol. Prostomium anteriorly bilobed, forming two broadly swollen lobes (Fig. 2A ), continuing posteriorly as narrow, undulating caruncle to anterior margin of chaetiger 2 (Fig. 2B ). Palps short, thick, tapering to pointed tip, not extending beyond chaetiger 3 (Figs 2A , 3A ). Chaetiger 1 reduced, notopodia reduced to flattened lamella, lacking notochaetae (Fig. 3A ); neuropodia with well-developed pre- and postchaetal lamellae (Fig. 3F ) and fascicles of capillaries. Notopodia of chaetigers 2-4 shifted dorsally to medial position, with pre- and postchaetal lamellae forming three rows enclosing cluster of modified spines (Figs 2C, D , 3A, F ). Notopodia of chaetigers 5-8 gradually shifted to lateral position (Fig. 3A, F ). Notopodia from chaetiger 5 and neuropodia from chaetiger 2 with well-developed pre- and postchaetal lobes. Figure 2. Lindaspio polybranchiata sp. nov. (Paratype, MBM 304662) A anterior end, dorsal view B caruncle C modified notopodial spines from anterior chaetiger D tip of modified notopodial spine. Figure 3. Lindaspio polybranchiata sp. nov. (Paratype, MBM 304663) A anterior end in dorsal view B anterior segments in ventral view, starting from segment 20 C median segments in ventral view D posterior end in dorsal view E posterior end in ventral view F anterior end in lateral view G parapodium from segment 12 H parapodium from segment 31; I. parapodium from segment 51. Scale bars: 1 mm ( A, E ); 500 µm ( B-D, F ); 250 µm ( G-I ). Dorsal branchiae fingerlike, appear from chaetiger 2 (Fig. 3A ) and remaining short to chaetiger 30, thereafter branchiae becoming thinner, longer, extending to dorsal midline. Ventral branchiae absent in the anterior part (Fig. 3G ). From chaetiger 20 small neuropodial expansion (Fig. 3B ), becoming well-developed neuropodial branchiae (Fig. 3C ) at chaetiger 40, until about chaetiger 80, becoming longer, more cylindrical, nearly reaching ventral midline, but never as long as dorsal branchiae (Figs 3H, I , 4A ). Figure 4. Lindaspio polybranchiata sp. nov. (Paratype, MBM 304662) A ventral view, middle part B anterior notochaetae C notopodial hooded hooks D anterior neurochaetae E details of neurochaetae F neuropodial hooded hook. Notochaetae of chaetigers 2-4 modified into cluster of about 15 heavy spines (Figs 2C , 3A ); subsequent notochaetae numerous, thin capillaries (Fig. 4B ) until about chaetiger 60 where hooded hooks appear; capillaries become heavier and more limbate in far posterior segments; individual notopodial hooks strongly curved, with pointed tips without minute teeth (Fig. 4C ). Anterior neurochaetae include row of heavy spines and ventral bundle of thin capillaries (Fig. 4D ); neuropodial spines each with smooth shaft that tapers gradually, then continues as fine, pointed tip with fine bristles sometimes visible along edge (Fig. 4E ); spines present until about chaetiger 40, then accompanied with thin capillaries; these capillaries accompanied by neuropodial hooded hooks from about chaetiger 65; each hook smaller, more delicate than notopodial hooks, without minute teeth (Fig. 4F ). Pygidium simple, conical, lacking cirri (Fig. 3D, E ). GenBank Accession Number: COI OQ582086, 16S OQ592054, 18S OQ592055. Remarks. As mentioned above, three species have been reported in the genus Lindaspio . The new species is easily distinguished from L. dibranchiata and L. sebastiena in having a narrow, undulating caruncle, while L. sebastiena has no caruncle and L. dibranchiata has a short, mounded caruncle. The new species resembles L. southwardorum in having similar caruncle, ventral branchiae and dorsal clusters of spines in anterior notopodia, while the latter differs in having first neuro- branchiae from chaetiger 55 (vs. chaetiger 20 in the new species) and having more modified spines on chaetigers 2-4 (20 vs. 15). The BLAST percent identity of the 18S sequence between the new species and Lindaspio dibranchiata is 99% (1758/1762 bp), suggesting that they are congeneric. Additionally, the COI and 16S sequences of our specimen are identical to those of Lindaspio sp. (GenBank accession number OK032597.1), which confirms that the unverified species of Lindaspio in GenBank is a Lindaspio polybranchiata sp. nov. Etymology. The species is so named because it has more neuropodial branchiae than the congeners. Distribution. Currently only known from the type locality, near Hainan Island, China, at a depth of 1758 m (Fig. 1 ).