#ZooKeys ZooKeys 1215: 139-149 (2024) DOI: 10.3897/zookeys.1215.129623 Research Article Distribution extension of a vent scale worm Branchinotogluma bipapillata (Polychaeta, Polynoidae) in the Indian Ocean Won-Kyung Lee!2®, Se-Joo Kim'2® 1 Division of Biomedical Research, Korea Research Institute Bioscience and Biotechnology, Daejeon 34141, Republic of Korea 2 Division of EcoScience, Ewha Womans University, Seoul 03760, Republic of Korea 3 KRIBB School, University of Science and Technology, Daejeon, 34113, Republic of Korea Corresponding author: Se-Joo Kim (biosejoo@kribb.re. kr) OPEN ro | ACCESS Academic editor: Andrew Davinack Received: 13 June 2024 Accepted: 2 September 2024 Published: 14 October 2024 ZooBank: https://zoobank. org/4A593809-AE76-458F-B085- 0D34B29105CC Citation: Lee W-K, Kim S-J (2024) Distribution extension of a vent scale worm Branchinotogluma bipapillata (Polychaeta, Polynoidae) in the Indian Ocean. ZooKeys 1215: 139-149. https://doi.org/10.3897/ zookeys.1215.129623 Copyright: © Won-Kyung Lee & Se-Joo Kim. This is an open access article distributed under terms of the Creative Commons Attribution License (Attribution 4.0 International - CC BY 4.0). Abstract Branchinotogluma Pettibone, 1985 is the most species-rich genus within the subfamily Lep- idonotopodinae Pettibone, 1983, comprising 18 valid species from chemosynthesis-based ecosystems in the Pacific and Indian Oceans. Here, we report a new distributional record of Branchinotogluma bipapillata Zhou, Wang, Zhang & Wang, 2018, at the hydrothermal vent sites on the northern Central Indian Ridge (nCIR). This record represents the northernmost occurrence of B. bipapillata in the Indian Ocean. We conducted a comparative study of the nCIR population and other documented populations using distributional information, mor- phological traits, and genetic markers (two mitochondrial [CO/, 76S rRNA] and one nuclear [18S rRNA] genes). While most morphological characters of B. bipapillata were consistent with those found in the Southwest Indian Ridge (SWIR), variations were noted in the segment with the last branchiae. Molecular data revealed that all populations of B. bipapillata form a single clade, indicating a wide distribution from the SWIR to nCIR, covering ~4,000 km across various ridges in the Indian Ocean. This study presents extensive distribution of a vent species with well-connected populations throughout the Indian Ocean, distinguishing it from many other vent species affected by the dispersal barrier in the Indian Ocean. Key words: 76S rRNA, 78S rRNA, CO71, deep-sea, hydrothermal vent, northern Central Indian Ridge, polynoids Introduction The subfamily Lepidonotopodinae Pettibone, 1983 consists of scale worms en- demic to chemosynthesis-based ecosystems (Wu et al. 2023). Currently, seven species from the Indian Ocean are identified within this subfamily: three Branchi- notogluma, two Branchipolynoe, and two Levensteiniella (Han et al. 2023). Branchinotogluma Pettibone, 1985, the most species-rich genus in the subfamily, comprises 18 species found in the Pacific and Indian Oceans (Han et al. 2023). Specifically, three Branchinotogluma species are distributed across different ridge systems in the Indian Ocean: B. bipapillata Zhou et al., 2018 in the South- west Indian Ridge (SWIR) and southern Central Indian Ridge (sCIR), B. jiaolongae Han et al., 2023 in the SWIR and Carlsberg Ridge (CR), and B. kaireiensis Han et al., 2023 in the sCIR and CR (Zhou et al. 2018, 2022; Han et al. 2023). 139 Won-Kyung Lee & Se-Joo Kim: Additional record of Branchinotogluma bipapillata Since the initial discovery of vent fields in the Indian Ocean in 2000, the Rodriguez Triple Junction, which links the SWIR, CIR, and Southeast Indian Ridge, was assumed to be a dispersal barrier for vent species within the Indian Ocean (Gamo et al. 2001; Chen et al. 2015). However, with the discovery of more vent fields and associated fauna, it now appears that the primary disper- sal barriers lie within the ridge system itself, mainly due to ridge offsets, rather than between different ridge systems (Sun et al. 2020). For instance, the vent crab Austinograea rodriguezensis Tsuchida & Hashimoto, 2002 was absent from the southern SWIR (SSWIR) but was found in the northern SWIR (nSWIR) and showed panmixia with populations from other ridges like the sCIR. Similar- ly, the distribution of the hairy snail Alviniconcha species complex shows con- nectivity between different ridges, northern CIR (nCIR) and CR, but subdivisions between the sCIR and nCIR on the same CIR (Sun et al. 2020; Jang et al. 2023). While B. bipapillata has been reported from vent fields on two ridge systems, the SWIR and CIR, morphological and genetic studies were previously only conducted on specimens from the sSWIR. In this study, we collected Branchi- notogluma species from hydrothermal vent fields on the nCIR and compared morphological and molecular data with those from vent fields on the sSWIR. Materials and methods Specimens of Branchinotogluma were collected from hydrothermal vents in the nCIR during the 2023 KIOST expedition aboard the R/V /sabu (Fig. 1, Table 1) using a suction sampler and scoop mounted on the ROV ROPOS (Canadian Scientific Submersible Facility). Upon collection, a piece of elytron or parap- odium from each specimen was dissected and preserved in 99% ethanol for molecular analysis. The entire body of the specimens was preserved in either 10% neutral buffered formalin or 70% ethanol for morphological studies. For determination of morphological characters, all specimens were exam- ined under a stereomicroscope (Stemi 508; Carl Zeiss, Germany). Specimen photographs were captured using a color camera (Axiocam 208 color; Carl Zeiss, Germany) and a DSLR camera (EOS 5D Mark IV; Canon, Tokyo, Japan). Images were processed with ZEN 3.3 blue edition (Carl Zeiss, Germany) and Helicon Focus software (Helicon Soft Ltd., Kharkov, Ukraine), and further edited using Adobe Photoshop 2022 (Adobe, San Jose, CA, USA). Specimen morphol- ogy was recorded following characters and states listed in Zhou et al. (2018). A small piece of elytron or parapodium was used for total genomic DNA ex- traction using the AccuPrep® Genomic DNA Extraction Kit (Bioneer, Daejeon, South Korea), following the manufacturer’s instructions. Partial cytochrome c oxidase subunit 1 (CO7) and 78S rRNA (78S) sequences were amplified follow- ing the protocols in Lee et al. (2021) and Jimi et al. (2021), respectively. For 16S rRNA (76S), the primers 16SA (5'-CGCCGTTTATCAAAAACAT-3’) and 16Sbr (5'-CCGGTYTGAACTCAGATCAYG-3’) (Palumbi et al. 1991; Palumbi 1996) were used. Polymerase chain reaction (PCR) was conducted using a SimpliAmp™ Thermal Cycler (Applied Biosystems, Life technologies) under the following conditions: initial denaturation at 94 °C for 2 min; 5 cycles at 95 °C for 10 s, 42 °C for 30 s, and 72 °C for 60 s; 35 cycles at 95 °C for 10 s, 48 °C for 30 s, and 72°C for 60 s; with a final extension at 72 °C for 2 min. PCR products were sent to Macrogen (Seoul, Korea) for Sanger sequencing. ZooKeys 1215: 139-149 (2024), DOI: 10.3897/zookeys.1215.129623 140 Won-Kyung Lee & Se-Joo Kim: Additional record of Branchinotogluma bipapillata 10°N 10°S 4, 20°S 30°S 40°S |_|Morphology + Molecular data Molecular data SriLanka No data & ye ie Indian Ocean ® Onbada / Onnare Saero / Onnuri Cheoeum ar } O Madagascar ©@ Solitaire % Q A Edmond ‘oe Kairei a et a Tiancheng sw S r “a _A Duangiao Longai 1000m 40°E 60°E T70°E 80°E 90°E Figure 1. Map displaying the geographic distribution of Branchinotogluma bipapillata in the Indian Ocean. Red indicates sampling locations from this study and black indicates records of B. bipapillata from previous studies. Some closely situated sampling sites (< 10 km apart, such as Onbada and Onnare, Saero and Onnuri) are marked with a single square. Table 1. Sampling information of newly obtained Branchinotogluma bipapillata specimens from the nCIR and their Gen- Bank accession numbers sequenced in this study. Voucher KRIBB310101- KRIBB310102 KRIBB310103- KRIBB310107 KRIBB310108- KRIBB310110 KRIBB310111- KRIBB310112 KRIBB310113- KRIBB310116 Sampling site | Latitude (S), Longitude (E) Depth (m) Cheoeum Onnuri Onnare Onbada Saero 12°37.1'S;66°7-6E 11°24.9'S, 66°25.4'E 9°47.4'S, 66°41.9'E 9°48.9'S, 66°40.6'E 11°19.7'S, 66°26.9'E 3018 2009 2993 2563 3256 GenBank Accession Numbers C01 16S 18S PP600168- PP600150- PP600184- PP600169 PP600151 PP600185 PP6001 70- PP600152- PP600186- PP600174 PP600156 PP600190 PP600175- PP600157- PP600191- PP600177 PP600159 PP600193 PP600178- PP600160- PP600194- PP600179 PP600161 PP600195 PP600180- PP600162- PP600196- PP600183 PP600165 PP600199 New sequences were aligned with those of other Lepidonotopodinae species from GenBank (Suppl. material 1: table S1) using Geneious Prime ver. 2023.0.1 (Biomatters, Auckland, New Zealand). Sequence divergence for the CO7 and 16S genes was calculated using the p-distance method in MEGA11 (Tamura et al. 2021). For phylogenetic analysis, the three genes were concatenated using ZooKeys 1215: 139-149 (2024), DOI: 10.3897/zookeys.1215.129623 141 Won-Kyung Lee & Se-Joo Kim: Additional record of Branchinotogluma bipapillata Geneious Prime. The best evolutionary model, GTR+I+G, was selected using jModelTest ver. 2.1.8 (Darriba et al. 2012). The phylogenetic tree was construct- ed using the maximum-likelihood method with raxmlGUI 2.0 (Edler et al. 2021). All specimens used in this study are deposited at the Korea Research Insti- tute of Bioscience and Biotechnology. Results Family Polynoidae Kinberg, 1856 Subfamily Lepidonotopodinae Pettibone, 1983 Genus Branchinotogluma Pettibone, 1985 Branchinotogluma bipapillata Zhou, Wang, Zhang & Wang, 2018: 528-533, figs 1-7; table 1. Material examined. INDIAN OCEAN « 2 3; Cheoeum; 12°37.1'S, 66°07.6'E; depth 3018 m; 28 Mar. 2023; W-K Lee leg.; hydrothermal vent; GenBank: PP600168- PP600169; KRIBB310101 to KRIBB310102 + 2 @, 2 9, 1 undetermined; Onnuri; 11°24.9'S, 66°25.4'E; depth 2009 m; 1-2 Apr. 2023; W-K Lee leg.; hydrothermal vent; GenBank: PP600170- PP600174; KRIBB310103 to KRIBB310107 + 1 &, 2 undeter- mined; Onnare; 9°47.4'S, 66°41.9'E; depth 2993 m; 3 Apr. 2023; W-K Lee leg.; hydro- thermal vent; GenBank: PP600175- PP600177; KRIBB310108 to KRIBB310110 « 1 3,1 9; Onbada; 9°48.9'S, 66°40.6'E; depth 2563 m; 4 Apr. 2023; W-K Lee leg.; hydro- thermal vent; GenBank: PP600178- PP600179; KRIBB310111 to KRIBB310112 + 2 3, 2 2; Saero; 11°19.7'S, 66°26.9'E; depth 3256 m; 7 Apr. 2023; W-K Lee leg.; hydro- thermal vent; GenBank: PP600180- PP600183; KRIBB310113 to KRIBB310116. Description. Specimens relatively well preserved, with 21 segments, 12.0- 51.0 mm in length and 5.0-16.6 mm in width. Body shape fusiform, tapered anteriorly and posteriorly (Fig. 2A, B, Table 2). Pairs of elytra on elytrophores on segments 2, 4, 5, 7, 9, 11, 13, 15, 17, and 19; elytra oval to subreniform, white, slightly transparent, with a smooth surface (Fig. 2C-E). Dorsal cirri on segments 3, 6, 8, 10, 12, 14, 16, 18, 20, and 21, extending beyond the tips of neurochaetae. Branchiae arborescent; grouped in two, one at base of the no- topodia and another at base of dorsal tubercles or elytrophores; starting from segment 3 and ending between segments 18 or 21 (Table 2). Prostomium bilobed, triangular anterior lobes with slender frontal filaments (Fig. 2F). Median antennae on anterior notch, with a cylindrical ceratophore and subulate style; palps thick, smooth, and end in subulate tips; lateral antennae and eyes absent (Fig. 2F). Tentacular segment fused to prostomium, with pair of tentacular cirri on each side, and a small acicular lobe at the base of tentac- ulophore; tentacular cirri slender (Fig. 2F). First segment not distinct, fused to prostomium. Pharynx with five dorsal and four ventral papillae in one immature individual, but not seen in others (Fig. 2G). Second segment with first pair of elytrophores, ventral cirri, and bi- ramous parapodia. Third segment with ventral cirri and first pair of branchiae. Fourth to last segments with ventral cirri and biramous parapodia. Notopodia smaller than neuropodia; notochaetae stout, few, arranged in radiating bundles; neurochaetae slender, numerous, forming a fan shape (Fig. 2H—-K). ZooKeys 1215: 139-149 (2024), DOI: 10.3897/zookeys.1215.129623 142 Won-Kyung Lee & Se-Joo Kim: Additional record of Branchinotogluma bipapillata Figure 2. Branchinotogluma bipapillata specimens collected from the nCIR A dorsal and ventral views of male (KRIBB310116) B dorsal and ventral views of female (KRIBB310105) C 1:8" left elytra D 9-10" left elytra of male (KRIBB310103) E 9% 10" left elytra of female (KRIBB310110) F head featuring prostomium, palps, tentacular cirri, and first parapodia on segment 2 (KRIBB310112) G everted pharynx with dorsal and ventral papillae (KRIBB310108). Anterior and posterior views of left parapodia on (H-I) segment 2 and (J-K) segment 11 (KRIBB310106). Scale bars: 5 mm (A-E); 0.5 mm (F, G); 1 mm (H-K). Sexual dimorphism evident. In males, posterior segments modified (Fig. 3A) with 10" elytra and elytrophores much smaller than 9% (Figs 2D, 3A, Table 2); ventral papillae present on segments 12-13, long, tapering, with slender tips extending to next segment; ventral lamellae on segments 14-17, round (Fig. 3B). In females, posterior segments not modified (Fig. 3C), with 10" elytra and elytrophores similar to 9* (Figs 2E, 3C, Table 2); ventral papillae present on segments 11-15, short and blunt (Fig. 3D). ZooKeys 1215: 139-149 (2024), DOI: 10.3897/zookeys.1215.129623 143 Won-Kyung Lee & Se-Joo Kim: Additional record of Branchinotogluma bipapillata Distribution. Indian Ocean (depth 1732-3256 m): Longqi and Duangiao vent fields on the southern Southwest Indian Ridge; Tiancheng vent field on the northern Southwest Indian Ridge; Edmond vent field on the southern Central Indian Ridge; Onnare, Onbada, Saero, Onnuri, and Cheoeum vent fields on the northern Central Indian Ridge. Remarks. Comparisons of key morphological characters between the geo- graphically distant populations are present in Table 2. The key characters of the nCIR specimens of B. bipapillata largely correspond with those of the SWIR specimens (Zhang et al. 2018). However, the two populations differ in the last segment with branchiae in females (Segment 19 in sSWIR compared with seg- ment 18 or 21 in nCIR; Table 2). Among the 16 specimens from the nCIR population, 10 specimens with body length greater than 20 mm were well-developed in all features indicating adult morphology, while characters of sexual dimorphism were not observed in 6 specimens shorter than 20 mm. DNA barcoding and phylogenetic analysis. Partial sequences of CO7, 16S, and 78S were recovered from 16 specimens collected from the nCIR. As shown in Table 1, 48 newly obtained sequences have been deposited in GenBank. In CO1, the mean intra-population variation was 0.56% for nCIR and 0.65% for SWIR, with an inter-population variation of 1.00% (Table 3). In 76S, the mean intra-population variation was 0.27% for nCIR and 0.33% for SWIR, with an in- ter-population variation of 0.39%. In 78S, the mean intra-population variation was 0.01% for nCIR and 0.00% for SWIR, with an inter-population variation of 0.004%. The interspecific variation between B. bipapillata and other congeners ranged from 18.63% to 21.88% in CO7, and from 13.11% to 19.08% in 76S (Suppl. mate- rial 1: table S2). In 18S, the interspecific variation ranged from 1.69% to 3.80%. Table 2. Morphological comparison of Branchinotogluma bipapillata from the nCIR and sSWIR. Region en nCIR 24.4-48.0 20,5-511,0 PBA:0= 1758 SWIR 23.07 32.3 Sex (# of ind.) th th Last segment Number of dorsal/ventral 9 to 10" elytrophore Reference with branchiae papillae on pharynx diatmeter ratio Male (5) 18 2.25-2.64 This study Not observed Female (8) 18 or 21 1.08-1.46 Undetermined (3) 18 5/4* 1.23=1,28 Male (1) 18 5/5 N/A Zhou et al. 2018 Female (2) 19 N/A *Observed in a single specimen (KRIBB310108; Fig. 2G). Table 3. Sequence divergence (%) among three Branchinotogluma bipapillata populations based on partial CO7 gene (553 bp). Populations (# of ind.; intra) nCIR (16; 0.56) sCIR (1; NC*) SWIR (5; 0.65) *not calculated. nCIR sCIR SWIR 0.70 - (0.20-1.18) 1.00 0.47 - (0.00-1.65) (0.20-1.19) ZooKeys 1215: 139-149 (2024), DOI: 10.3897/zookeys.1215.129623 144 Won-Kyung Lee & Se-Joo Kim: Additional record of Branchinotogluma bipapillata The maximum likelihood phylogenetic tree, constructed with concatenated sequences of CO7, 16S, and 78S (Fig. 4), shows the SWIR and nCIR populations of B. bipapillata clustering together as a single clade, indicating no significant divergence between populations from different ridges. Within the Branchinoto- gluma genus, B. bipapillata is closely related to a clade including B. kaireiensis, B. pettiboneae Wu et al., 2019, and B. robusta Wu et al., 2023. as... Pr. - Figure 3. Sexually dimorphic characters of Branchinotogluma bipapillata A dorsal view of posterior segments B ventral view of segments 12-17 of male (KRIBB310116) C dorsal view of posterior segments D ventral view of segments 11-15 of female (KRIBB310105). Arrows point to 9" and 10" elytrophores (EP) pointed with arrows. Ventral papillae are outlined in red and ventral lamellae in blue. Scale bars: 2 mm (A, C); 1 mm (B, D). KRIBB310105 KRIBB310115@ KRIBB310110 @ : ; KRIBB310109 @ B. bipapillata 10.| 2158310101 KRIBB310104 @ KRIBB310116 @ KRIBB310112 KRIBB310102 @ KRIBB310107 @ KRIBB310113 RSI035274 KRIBB310106 @ RS|O35277@ KRIBB310108 & KRIBB310114 KRIBB310103 KRIBB310111 96 B. kaireiensis B. pettiboneae B. robusta 62 B. ovata B. elytropapillata B. sagamiensis 93 B. sandersi B. jiaolongae B. tunnicliffeae 69 100 B. marianus 96 B. nikkoensis 100 B. nanhaiensis B. japonicus B. hessleri B. segonzaci Branchiplicatus cupreus (KY684706, MH127418, MH124628) 91 0.03 Figure 4. Maximum-likelihood phylogenetic tree of Branchinotogluma species based on concatenated sequences of the CO7, 16S, and 18S genes. Branchinotogluma bipapilla- ta species are highlighted with a gray box. Red and black squares represent nCIR and SSWIR populations, respectively. GenBank accession numbers of the CO7, 16S and 18S genes of the outgroup are noted next to the species names. Maximum-likelihood boot- strap support values > 60 are displayed next to the nodes. ZooKeys 1215: 139-149 (2024), DOI: 10.3897/zookeys.1215.129623 145 Won-Kyung Lee & Se-Joo Kim: Additional record of Branchinotogluma bipapillata Discussion and conclusion The vent scale worm B. bipapillata is widely distributed in the Indian Ocean, but comprehensive morphological and molecular data are lacking across all deep-sea oceanic ridges, and specimens are rarely reported at each sampling site (Fig. 1; only five specimens of B. bipapillata from the SWIR were barcoded with CO7, and only two sequences of 76S and 78S are available from SWIR specimens). In this study, 16 individuals, including female, male, and immature specimens of B. bipapillata from the nCIR were observed, enriching descrip- tions of features such as all elytra, and improving the molecular description of this species with both nuclear and mitochondrial gene sequences. Key mor- phological characters, such as the presence of an acicular lobe on the tentac- ulophore and the position of segmental ventral papillae, showed general con- gruence between the sSWIR and nCIR populations. Additionally, CO7 barcode sequences revealed a mean intraspecific variation of 0.72% in B. bipapillata, which is within the variation range observed in other Branchinotogluma spe- cies (0.00-1.05%; Suppl. material 1: table S2). Thus, molecular data on genetic distances within and between populations showed no significant differences, and the phylogenetic analysis revealed a single clade of B. bipapillata, with no divergence between populations (Fig. 4, Table 3). Based on these morpholog- ical and molecular findings, the southernmost and northernmost populations appear to be well connected, forming a single genetic population with minimal morphological variability. Other vent endemic species in the Indian Ocean, such as the mussel Bathy- modiolus marisindicus Hashimoto, 2001, the snail Chrysomallon squamiferum Chen et al., 2015, the crab A. rodriguezensis, the barnacle Neolepas marisindi- ca Watanabe et al., 2018, and the worm Ophryotrocha jiaolongi Zhang et al., 2017, all show a wide distribution range on the SWIR and CIR (Sun et al. 2020; Zhou et al. 2022). However, unlike the B. bipapillata populations in this study, most of these species exhibit low connectivity between populations, likely due to ridge offsets acting as dispersal barriers between the sSWIR and nSWIR, which do not seem to affect the connectivity of B. bipapillata (Sun et al. 2020; Zhou et al. 2022). Although the reproductive and larval development strategies of B. bipapillata are not fully understood, observations of other species within the same subfamily suggest that B. bipapillata likely have lecithotrophic larvae (Van Dover et al. 1999; Jollivet et al. 2000). This larval type, capable of traveling long distances in oligotrophic deep-sea environments, might partially explain the high connectivity of B. bipapillata populations across ~4,000 km of different ridges within the Indian Ocean. Many studies have considered geological and hydrological features, along with the dispersal abilities of species, to explain the distribution of vent species (Slatkin 1987; Vrijenhoek 2010; Taylor and Roterman 2017; Perez et al. 2021). However, to fully understand the broad geographical distribution of these spe- cies, it is also crucial to consider their ability to adapt to diverse vent environ- ments across different ridge systems. To further elucidate the strategies that enable species such as B. bipapillata to inhabit separate and geographically distant vent fields with no genetic differentiation, future studies should consid- er in vitro experiments for culturing as well as transcriptomic and genomic level data of populations. ZooKeys 1215: 139-149 (2024), DOI: 10.3897/zookeys.1215.129623 146 Won-Kyung Lee & Se-Joo Kim: Additional record of Branchinotogluma bipapillata Acknowledgements We thank all scientists and crew members of the R/V /sabu from KIOST for their support in sampling and data collection. Additional information Conflict of interest The authors have declared that no competing interests exist. Ethical statement No ethical statement was reported. Funding This work was supported by the Basic Science Research Program of the National Re- search Foundation of Korea, funded by the Ministry of Education (2021R111A2044998), the Korea Institute of Marine Science & Technology Promotion funded by the Ministry of Oceans and Fisheries, Korea (RS-2021-KS211514), and the Korea Research Institute of Bioscience and Biotechnology Research Initiative Program. Author contributions Conceptualization: SUK, WKL. Formal analysis: WKL. Funding acquisition: SJK. Supervision: SJK. Visualization: WKL. Writing - original draft: WKL. Writing - review and editing: SUK, WKL. Author ORCIDs Won-Kyung Lee ® https://orcid.org/0000-0001-7283-298X Se-Joo Kim © https://orcid.org/0000-0003-1653-072X Data availability All of the data that support the findings of this study are available in the main text or Supplementary Information. References Chen C, Copley JT, Linse K, Rogers AD (2015) Low connectivity between ‘scaly-foot gas- tropod’ (Mollusca: Peltospiridae) populations at hydrothermal vents on the South- west Indian Ridge and the Central Indian Ridge. Organisms Diversity & Evolution 15: 663-670. https://doi.org/10.1007/s13127-01 5-0224-8 Darriba D, Taboada GL, Doallo Rn, Posada D (2012) jModelTest 2: more models, new heuristics and high-performance computing. Nature Methods 9: 772. https://doi. org/10.1038/nmeth.2109 Edler D, Klein J, Antonelli A, Silvestro D (2021) raxmIGUI 2.0: a graphical interface and toolkit for phylogenetic analyses using RAXML. Methods in Ecology and Evolution 12: 373-377. https://doi.org/10.1111/2041-210X.13512 Gamo T, Chiba H, Yamanaka T, Okudaira T, Hashimoto J, Tsuchida S, Ishibashi J-i, Kata- oka S, Tsunogai U, Okamura K (2001) Chemical characteristics of newly discovered black smoker fluids and associated hydrothermal plumes at the Rodriguez Triple Junction, Central Indian Ridge. Earth and Planetary Science Letters 193: 371-379. https://doi.org/10.1016/S0012-821X(01)00511-8 ZooKeys 1215: 139-149 (2024), DOI: 10.3897/zookeys.1215.129623 147 Won-Kyung Lee & Se-Joo Kim: Additional record of Branchinotogluma bipapillata Han Y, Zhou Y, Chen C, Wang Y (2023) Diversity and biogeography of scale worms in the subfamily Lepidonotopodinae (Annelida: Polynoidae) from Indian Ocean hydrother- mal vents with descriptions of four new species. Zoological Journal of the Linnean Society 201: 290-304. https://doi.org/10.1093/zoolinnean/zlad140 Jang S-J, Cho S-Y, Li C, Zhou Y, Wang H, Sun J, Patra AK, Won Y-J (2023) Geographi- cal subdivision of Alviniconcha snail populations in the Indian Ocean hydrothermal vent regions. Frontiers in Marine Science 10: 1139190. https://doi.org/10.3389/ fmars.2023.1139190 Jimi N, Hookabe N, Moritaki T, Kimura T, Imura S (2021) First evidence of male dwarf- ism in scale worms: A new species of Polynoidae (Annelida) from hermit crab and molluscan shells. Journal of Zoological Systematics and Evolutionary Research 59: 801-818. https://doi.org/10.1111/jzs.12463 Jollivet D, Empis A, Baker M, Hourdez S, Comtet T, Jouin-Toulmond C, Desbruyeres D, Tyler P (2000) Reproductive biology, sexual dimorphism, and population structure of the deep sea hydrothermal vent scale-worm, Branchipolynoe seepensis (Polychaeta: Polynoidae). Journal of the Marine Biological Association of the United Kingdom 80: 55-68. https://doi.org/10.1017/S002531 5499001563 Lee W-K, Lee GH, Ju S-J, Kim S-J (2021) Additional Records of the Hydrothermal Vent Scale Worm Branchinotogluma segonzaci (Polynoidae: Lepidonotopodinae) from the North Fiji Basin and Tonga Arc. Animal Systematics, Evolution and Diversity 37: 273-279. https://doi.org/10.5635/ASED.2021.37.4.027 Palumbi SR (1996) Nucleic Acids II: Polymerase Chain Reaction. In: Hillis D, Moritz C, Mable B (Eds) Molecular Systematic, 2"? edn. Sinauer Associates, Inc., Sunderland, 205-247. Palumbi SR, Martin AP Romano SL, McMillan WO, Stice L, Grabowski G (1991) The Sim- ple Fool’s Guide to PCR. Dept. of Zoology, University of Hawaii, Honolulu. Perez Mv, Sun J, Xu Q, Qian P-Y (2021) Structure and connectivity of hydrothermal vent communities along the mid-ocean ridges in the West Indian Ocean: a review. Fron- tiers in Marine Science 8: 744874. https://doi.org/10.3389/fmars.2021.744874 Slatkin M (1987) Gene flow and the geographic structure of natural populations. Science 236: 787-792. https://doi.org/10.1126/science.3576198 Sun J, Zhou Y, Chen C, Kwan YH, Sun Y, Wang X, Yang L, Zhang R, Wei T, Yang Y (2020) Nearest vent, dearest friend: biodiversity of Tiancheng vent field reveals cross-ridge similarities in the Indian Ocean. Royal Society Open Science 7: 200110. https://doi. org/10.1098/rsos.200110 Tamura K, Stecher G, Kumar S (2021) MEGA11: Molecular Evolutionary Genetics Analysis version 11. Molecular Biology and Evolution 38: 3022-3027. https://doi. org/10.1093/molbev/msab1 20 Taylor M, Roterman C (2017) Invertebrate population genetics across Earth’s largest hab- itat: The deep-sea floor. Molecular Ecology 26: 4872-4896. https://doi.org/10.1111/ mec.14237 Van Dover CL, Trask J, Gross J, Knowlton A (1999) Reproductive biology of free-living and commensal polynoid polychaetes at the Lucky Strike hydrothermal vent field (Mid-Atlantic Ridge). Marine Ecology Progress Series 181: 201-214. https://doi. org/10.3354/meps181201 Vrijenhoek RC (2010) Genetic diversity and connectivity of deep-sea hydrothermal vent metapopulations. Molecular Ecology 19: 4391-4411. https://doi.org/10.1111/ j.1365-294X.2010.04789.x Wu X, Zhan Z, Xu K (2019) Two new and two rarely known species of Branchinotoglu- ma (Annelida: Polynoidae) from deep-sea hydrothermal vents of the Manus Back- ZooKeys 1215: 139-149 (2024), DOI: 10.3897/zookeys.1215.129623 148 Won-Kyung Lee & Se-Joo Kim: Additional record of Branchinotogluma bipapillata Arc basin, with remarks on the diversity and biogeography of vent polynoids. Deep Sea Research Part |: Oceanographic Research Papers 149: 103051. https://doi. org/10.1016/j.dsr.2019.05.011 Wu X, Zhen W, Kou Q, Xu K (2023) Reevaluation of the systematic status of Branchino- togluma (Annelida, Polynoidae), with the establishment of two new species. Journal of Zoological Systematics and Evolutionary Research 2023: 1490800. https://doi. org/10.1155/2023/1490800 Zhang Y, Chen C, Qiu JW (2018) Sexually dimorphic scale worms (Annelida: Polynoi- dae) from hydrothermal vents in the Okinawa Trough: two new species and two new sex morphs. Frontiers in Marine Science 5: 112. https://doi.org/10.3389/ fmars.2018.00112 Zhou Y, Wang Y, Zhang D, Wang C (2018) Branchinotogluma bipapillata n. sp., a new branchiate scale worm (Annelida: Polynoidae) from two hydrothermal fields on the Southwest Indian Ridge. Zootaxa 4482: 527-540. https://doi.org/10.11646/zoot- axa.4482.3.5 Zhou Y, Chen C, Zhang D, Wang Y, Watanabe HK, Sun J, Bissessur D, Zhang R, Han Y, Sun D (2022) Delineating biogeographic regions in Indian Ocean deep-sea vents and implications for conservation. Diversity and Distributions 28: 2858-2870. https://doi. org/10.1111/ddi.13535 Supplementary material 1 Supplementary information Authors: Won-Kyung Lee, Se-Joo Kim Data type: docx Explanation note: table $1. Sample information and accession numbers of the Branchi- notogluma species used in this study (new sequences are highlighted in bold). table S2. Interspecific divergence (%) of mitochondrial CO7 (below left) and 16S (upper right) genes of Branchinotogluma species. Mean intraspecific CO7 distances are displayed in bold along the diagonal. Copyright notice: This dataset is made available under the Open Database License (http://opendatacommons.org/licenses/odbl/1.0/). The Open Database License (ODbL) is a license agreement intended to allow users to freely share, modify, and use this Dataset while maintaining this same freedom for others, provided that the original source and author(s) are credited. Link: https://doi.org/10.3897/zookeys.1215.129623.suppl1 ZooKeys 1215: 139-149 (2024), DOI: 10.3897/zookeys.1215.129623 149