Description of two new species of the genus Trochus Linnaeus, 1758 (Gastropoda, Trochidae) from the South China Sea

265 Description of two new species of the genus Trochus Linnaeus, 1758 (Gastropoda, Trochidae) from the South China Sea Peng-Jin Zhu1,2 , Cheng-Rui Yan1,2, Hong-Qiang Yang3,4, Li-Sha Hu1,2,5 , Yun-Wei Dong1,2 1 Key Laboratory of Mariculture, Ministry of Education, Ocean University of China, Qingdao 266003, China 2 Shandong Key Laboratory of Green Mariculture and Smart Fishery, Fisheries College, Ocean University of China, Qingdao 266003, China 3 Key Laboratory of Ocean and Marginal Sea Geology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, China 4 Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou 510301, China 5 Frontiers Science Center for Deep Ocean Multispheres and Earth System, Qingdao 266003, China Corresponding authors: Li-Sha Hu ([email protected]); Yun-Wei Dong ([email protected]) Copyright: © Peng-Jin Zhu et al. This is an open access article distributed under terms of the Creative Commons Attribution License (Attribution 4.0 International – CC BY 4.0). Research Article Abstract Two new species of the gastropod family Trochidae, Trochus nanhai sp. nov. and Trochus parvus sp. nov., are described from the South China Sea. Morphological comparisons and species delimitation analyses based on molecular phylogeny support the distinctiveness of the two species. Trochus nanhai sp. nov. exhibits substantial variation in shell morphology, which increases the difficulty of morphological characterization. Nevertheless, it can be distinguished by diagnostic characters such as the presence and arrangement of pustules along the suture of each whorl. Additionally, multiple species delimitation methods (ASAP, ABGD, bPTP and GMYC) revealed potential taxonomic inconsistencies within previously identified Trochus species. To assist visualization and facilitate future taxonomic studies, we applied 3D modeling techniques and extracted geometric morphometric parameters of two new species. Detailed morphological descriptions, diagnostic characters, illustrations, and 3D models are provided. This study enhances our understanding of Trochus diversity and taxonomy. Key words: 3D modeling, geometric morphometrics, mitochondrial COI gene, new species, South China Sea, Top shells, Trochus Introduction Trochidae Rafinesque, 1815 is a large heterogeneous family of gastropods, with species distributed globally, predominantly in tropical and subtropical regions (Williams et al. 2008). Trochidae, a diverse family within the superfamily Trochoidea, comprises more than 2000 extant species grouped into approximately 500 recognized genera (Hickman et al. 1996; Ponder and Lindberg 2008; Williams et al. 2010). Within Trochidae, the genus Trochus Linnaeus, 1758 is found all over the Indo-West Pacific and commonly associated with coral reef habitats and diet algae (Fleure and Gettings 1907; Purcell and Ceccarelli 2021). Top shells (Trochus species) hold significant economic value, not only as a traditional food source but also as an important export commodity, with their Academic editor: Fedor Konstantinov Received: 5 August 2025 Accepted: 18 November 2025 Published: 19 December 2025 ZooBank: https://zoobank.org/ FC931A0F-1744-4625-8BEB8789BD9836F0 Citation: Zhu P-J, Yan C-R, Yang H-Q, Hu L-S, Dong Y-W (2025) Description of two new species of the genus Trochus Linnaeus, 1758 (Gastropoda, Trochidae) from the South China Sea. ZooKeys 1264: 265–280. https://doi. org/10.3897/zookeys.1264.167854 ZooKeys 1264: 265–280 (2025) DOI: 10.3897/zookeys.1264.167854 266 ZooKeys 1264: 265–280 (2025), DOI: 10.3897/zookeys.1264.167854 Peng-Jin Zhu et al.: New species of genus Trochus aragonite shells widely used in the manufacture of mother-of-pearl buttons and ornamental products (Gillett et al. 2020). Since the 1750s, Linnaeus laid the foundation for species classification by describing numerous taxa. Subsequently, Dillwyn applied this classification system to the genus Trochus, thereby advancing the taxonomic research of this group (Dillwyn 1817). Although many studies have provided additional images and morphological descriptions of Trochus species, the absence of clear morphological illustrations has left the issue of accurate species identification unresolved (Philippi 1845; Reeve 1860; Dodge 1958). Taxonomic research on Trochus in China began in the 1930s, when Zhang Xi conducted morphological and ecological studies on Trochus maculatus (Zhang 1962). The Taiwanese malacologist Lai Jingyang also contributed to the taxonomic understanding of the genus Trochus (Lai 1981). Based on the earlier studies, and Dong (2002) described nine Trochus species and identified a new species, T. zhangi. In recent years, studies focusing on the morphology of the genus Trochus have been scarce. Notably, Sawayama et al. (2022) carried out a detailed investigation of T. histrio and T. rota from Japan, analyzing both morphological traits and molecular markers to assess variation within and between species. The genus Trochus is highly diverse, and species-level identification is often challenging (Cunha et al. 2023). Some Trochus species, such as T. firmus and T. erythreus, or T. flammulatus and T. maculatus, exhibit highly similar shell morphologies, making it difficult to distinguish them based solely on external features (Tryon et al. 1898). Traditionally, species identification and description have relied primarily on morphological characteristics. With the development of molecular and imaging techniques, species delimitation has become more efficient and accurate. Among these, DNA barcoding plays a key role in identifying newly discovered species (Stoeckle 2003). However, an increasing number of taxonomic studies have shown that some species exhibit highly intraspecific shell variation and lack clear original descriptions, making image-based records alone insufficient for accurate taxonomic identification (Affenzeller et al. 2017). The emergence and development of 3D modelling techniques have enabled the extraction of key morphological traits by providing more comprehensive and detailed shape information. Moreover, 3D morphological data are becoming increasingly cost-effective and accessible for species-level studies, including intra-specific variation. For example, previous research has combined DNA barcoding and 3D morphological analyses to delimit species within the genus Pyrenaearia (Caro et al. 2019). In this study, we diagnose and describe two new Trochus species from the South China Sea. We apply multiple species delimitation methods to evaluate genetic divergence among Trochus species based on mitochondrial cytochrome c oxidase subunit I (COI) sequences. Additionally, we update the 3D models and extract detailed morphological characteristics of the new Trochus species, providing a valuable reference for future comparative taxonomic studies. Material and methods Sample collection Specimens were collected from coral reef habitats in the South China Sea (Fig. 1). Adductor muscle tissues from freshly collected individuals were flash-frozen 267 ZooKeys 1264: 265–280 (2025), DOI: 10.3897/zookeys.1264.167854 Peng-Jin Zhu et al.: New species of genus Trochus in liquid nitrogen and stored at -80 °C for subsequent DNA extraction. The remaining parts of the specimens were preserved at -20 °C and deposited in the Laboratory of Intertidal Ecophysiology, Qingdao, China. Morphological observation and 3D model construction Specimens were soaked in 5% hydrogen peroxide for 5 minutes to remove organic residues. The remaining crustose coralline algae were then carefully scraped off using a spatula. All specimens were photographed using a Nikon D3500 camera equipped with an AF-S macro lens (Nikon, Tokyo, Japan). Image stacks of standard views of the shells (Callomon 2019) were produced and combined using Helcon Focus v. 7.7.0. All photographs were enhanced in Adobe Photoshop 2019 (Adobe Systems, San Jose, CA, USA). The 3D models were constructed using Agisoft Metashape. To ensure comprehensive coverage, each specimen was rotated and photographed from multiple angles. For each specimen, photographs were aligned to determine camera positions and generate a sparse point cloud. Subsequently, depth maps were generated from the sparse point cloud and produced the final 3D model. From these models, we extracted shell morphometric parameters, including Ellipticity, Normalized Avg Curvature, and Sphericity, using the workflow described by Yan et al. (2024). All feature extraction procedures were based on Python scripts available on GitHub (https://github.com/yanchengrui123/Feature-extraction). Shell height and width were measured manually Figure 1. Sampling locations of Trochus species in the South China Sea. Red dots indicate collection sites of T. parvus sp. nov., while black dots indicate sites of T. nanhai sp. nov. The blue dots indicate the locations of islands. 15 ° 20 ° 105°E 110°E 115°E 120°E 2.0617 10.067 10 ° N N NN 500 km 268 ZooKeys 1264: 265–280 (2025), DOI: 10.3897/zookeys.1264.167854 Peng-Jin Zhu et al.: New species of genus Trochus using traditional caliper measurements in the field. The radulae were collected following the method described by Han et al. (2024) and examined using a Scanning Electron Microscope (SEM) after being thinly coated with gold. DNA Extraction and PCR Amplification DNA was extracted from muscle tissue using the CTAB protocol (Ding et al. 2018), and the COI gene was amplified with the universal primers LCO1490 and HCO2198 (Folmer et al. 1994). PCR reactions were performed in 25 µL volume, each containing 1 μL DNA and 24 uL PCR mix. The PCR mix comprised 12.5 μL of 2× Taq PCR Mix (Tiangen, Beijing), 1 μL of each 10 μM primer, and 9.5 μL of DNase-free ddH2O. PCR was performed with the following cycling conditions: 95 °C for 2 min; 30 cycles of 95 °C for 50 s, 45 °C for 50 s, and 72 °C for 50 s; followed by a final extension at 72 °C for 5 min. PCR amplicons were submitted to Sangon Biotech (Shanghai, China) for bidirectional sequencing using the same primer pair. We manually checked the quality of the sequence peak map and used SeqMan (DNASTAR Inc., USA) to assemble the forward and reverse sequences. Phylogenetic analyses The 24 newly generated COI sequences in this study were subjected to BLAST searches against the GenBank database to assist in grouping and taxonomic assignment of the specimens. To clarify the systematic status of Trochus specimens in this study, 30 Trochus COI sequences were retrieved from GenBank (see Suppl. material 1: table S1) to construct the phylogenetic trees. Coelotrochus viridis (Gmelin, 1791) GQ249683, Clanculus margaritarius (Philippi, 1846) PP652117, and Tectarius cumingii (Philippi, 1846) AJ488640 were selected as outgroup taxa. Alignment of COI sequences was conducted with MAFFT v. 7 (Katoh and Standley 2013) and ModelFinder was employed to identify the optimal substitution model (Kalyaanamoorthy et al. 2017). Maximum likelihood (ML) analysis was conducted using IQ-TREE with the GTR+F+I+G4 model and 1000 bootstrap replicates (Nguyen et al. 2015). Bayesian inference (BI) was performed using MrBayes with the GTR+I+G+F model, run for 50,000,000 generations with a burn-in of 25% (Ronquist et al. 2012). The resulting phylogenetic trees were visualized using iTOL (Letunic and Bork 2024). Multiple species delimitation methods were used to determine whether the newly identified species is genetically distinct from other congeners. Aligned COI sequences were submitted to the Automatic Partitioning (ASAP) website (https://bioinfo.mnhn.fr/abi/public/asap/asapold.html) using the Kimura (K80) model with a transition/transversion (ts/tv) ratio of 2.0 (Puillandre et al. 2021). The ASAP analysis provides partitioning scores, and the partition with the lowest score was selected as the optimal species delimitation. ABGD analysis was conducted using aligned sequences as input on the online platform (https://bioinfo.mnhn.fr/abi/public/abgd/abgdold.html; Puillandre et al. 2012), with the K2P model selected and a relative gap width set to 1.0. The ML phylogenetic tree was used as input for species delimitation analysis using the Bayesian implementation of the Poisson Tree Processes (bPTP) method on the online server (https://species.h-its.org/ptp/), with default parameters. Species delimitation using the General Mixed Yule-Coalescent (GMYC) model (Pons et 269 ZooKeys 1264: 265–280 (2025), DOI: 10.3897/zookeys.1264.167854 Peng-Jin Zhu et al.: New species of genus Trochus al. 2006) was performed in R with the splits package (Ezard et al. 2009), based on ultrametric trees generated in BEAST2 under the Yule model. The maximum number of putative species inferred from delimitation analyses was used to define species groups, and pairwise p-distance comparisons among groups were calculated using MEGA 11 (Kumar et al. 2018). Results Molecular analysis COI sequences (679 bp) of the newly sequenced Trochus specimens do not match any known Trochus species (GenBank: T. nanhai sp. nov. (PX057741– 61) T. parvus sp. nov. (PX058089–91). The BI and ML trees shared the same topology and comprised two major clades. However, the BI tree showed higher support values, particularly along the main branches (Fig. 2). The two new Trochus species were significantly different from other Trochus genetic lineages and were placed on two distinct branches within clade A. These results were further supported by genetic distance and morphological characteristics (see Remarks under the new species description). 0.1 100/1 100/1 85/0.99 80/- 100/1 98/- 98/0.97 100/1 91/1 100/1 100/1 93/1 98/1 98/1 89/0.98 100/0.85 100/1 -/0.92 -/0.98 -/0.99 -/0.83 -/0.78 100/1 94/- A B ASAP bPTP Trochus parvus sp. nov Trochus nanhai sp. nov Clanculus margaritarius (PP652117) Trochus (Coelotrochus) viridis (GQ249683) Tectarius cumingii (AJ488640) Osilinus (Trochus) kotschyi (LC029914) Priotrochus (Trochus) kotschyi (LC154939) Tectus (Trochus) tentorium (EU530152) Trochus radiatus (PQ276883) Trochus maculatus (OQ206908) Trochus maculatus (OQ206909) Trochus maculatus (OQ206910) Trochus maculatus (OP457075) Trochus maculatus (MN388970) Trochus maculatus (MN388972) Trochus maculatus (MN388973) Trochus maculatus (OP457073) Trochus maculatus (MN388971) Trochus maculatus (OP457074) Trochus intextus (MW277731) Trochus intextus (MW278668) Trochus histrio (AB505300) Trochus histrio (LC599069) Trochus stellatus (MN388974) Trochus stellatus (MN388975) Trochus stellatus (MN388976) Trochus incrassatus (GQ232374) Trochus cf. stellatus (OQ206913) Trochus stellatus (EU530135) Trochus sp (OQ206911) Trochus sp (OQ206912) Trochus rota (LC599066) Trochus rota (LC599059) Trochus rota (LC599065) GMYC ABGD Figure 2. Maximum likelihood (ML) and Bayesian inference (BI) phylogenetic trees of Trochus based on COI sequences. Bootstrap support values above 70% (ML) and posterior probabilities above 0.7 (BI) are shown. The color bar on the right indicates species clusters inferred by four species delimitation methods. 270 ZooKeys 1264: 265–280 (2025), DOI: 10.3897/zookeys.1264.167854 Peng-Jin Zhu et al.: New species of genus Trochus Species delimitation results varied among methods. ASAP identified 15 species, both ABGD and GMYC recovered 17 species, while bPTP delimited 18 species. The greatest variation in species delimitation occurs within clade A. All species delimitation methods consistently placed Trochus maculatus within clade B and supported its genetic divergence from other closely related species with high confidence. In the ASAP analysis, the sequence originally labeled as T. stellatus (MN388974–76) in GenBank was resolved within the clade containing T. histrio and T. intextus. Additionally, T. stellatus (OQ206912) and T. cf. stellatus (OQ206913) were identified as the same species by ASAP. However, ABGD, bPTP, and GMYC analyses all supported the separation of these two sequences as distinct species. Both ABGD and GMYC identified T. stellatus and T. histrio as a single species, whereas bPTP distinguished them as two separate species. All four species delimitation methods identified the Trochus species and the newly proposed species as distinct molecular operational taxonomic units (MOTUs) or putative species. Trochus parvus sp. nov. and T. nanhai sp. nov. exhibited interspecific K2P distances ranging from 10.65% to 29.53% and 9.21% to 25.12%, respectively, when compared with other congeners. While the mean K2P genetic distances within the newly described species were 0.23% for T. parvus sp. nov. and 0.72% for T. nanhai sp. nov. The observed interspecific K2P distances were more than ten times greater than the intraspecific distances, consistent with the commonly applied “10× rule” for species delimitation. Trochus stellatusa showed relatively low mean K2P distances of 1.48% and 5.03% with T. histrio and T. intextus, respectively. Trochus histrio exhibited 3.79% K2P values with T. intextus (Fig. 3). The average intraspecific K2P distance of Trochus species based on COI sequences ranged from 0% to 0.72%, indicating low and relatively stable genetic divergence within species (Table 1). Table 1. The average intraspecific Kimura 2-parameter (K2P) distance (%) was calculated based on COI sequences of Trochus species. Species Distance S.E. Trochus histrio 0 0 Trochus rota 0.54 0.27 Trochus stellatusa0.42 0.21 Trochus parvus sp. nov. 0.23 0.1 Trochus maculatusb0.13 0 Trochus maculatusc0.1 0.1 Trochus sp. 0.15 0.16 Trochus nanhai sp. nov. 0.72 0.26 Trochus intextus 0 0 Trochus kotschyi 0 0 Systematics Order Trochida Superfamily Trochoidea Rafinesque, 1815 Family Trochidae Rafinesque, 1815 Genus Trochus Linnaeus, 1758 Type species. Trochus maculatus Linnaeus, 1758; Recent, Indo-Pacific region. 271 ZooKeys 1264: 265–280 (2025), DOI: 10.3897/zookeys.1264.167854 Peng-Jin Zhu et al.: New species of genus Trochus Figure 3. Mean Kimura 2-parameter (K2P) pairwise genetic distances (%) among groups identified by the bPTP species delimitation method. Note: a: EU530135; b: MN388974– 76; c: MN388970–73; d: OQ206908–10. Trochus nanhai sp. nov. https://zoobank.org/52CD3716-4C4C-4514-8B08-EECB758B2B0C Etymology. The name “nanhai” is derived from the Chinese designation for the South China Sea, the only region where this species has been documented to date. Material examined. Holotype: LINE-SCSLH-20240601005, Complete specimen, deposited in the Laboratory of Intertidal Ecophysiology, Ocean University of China (OUC), Qingdao, China (Suppl. material 1). Paratype: LINE-SCSZQ-20240531001, LINE-SCSYSZ-20240521002, LINESCSMJ-20240501004 and LINE-SCSAL-20240601001, Complete specimen, same location as holotype (Suppl. material 1). Description. Shell: medium size, elate-conic and low-conic, solid and heavy, and falsely umbilicate. Spire composed of 7–8 planulate whorls, with 4–5 regular closely spaced spiral rows of uniform granules on each whorl (Fig. 4A–K). These granules are rounded, bead-like, or slightly compressed. Each whorl periphery bears prominent, evenly spaced pustules; these may be inconspicuous in small subadults (Fig. 4L). In elate-conic specimens, the whorl pustules gradually fuse during growth, resulting in smoother and more continuous beaded spiral ridges (Fig. 4A–E). The periphery of the body whorl exhibits 12–15 distinct longitudinal folds forming oblong nodules. The base of the shell is a little concave, sculptured with 11–12 concentric granulose lirae (Fig. 4F, I). The upper surface bears distinct, broad reddish-brown longitudinal stripes, approximately equal in width to the alternating whitish bands. The base bears a narrow row of spots corresponding to the outer colour pattern. The inner lip is thickened 272 ZooKeys 1264: 265–280 (2025), DOI: 10.3897/zookeys.1264.167854 Peng-Jin Zhu et al.: New species of genus Trochus Figure 4. Trochus nanhai sp. nov. A–C. Specimen LINE-SCSZQ-20240531001, elate-conic. A. Shell in apertural view; B. Shell in lateral view; C. Shell in apical view; D–F. Elate-conic specimen LINE-SCSYSZ-20240521002; D. Shell in lateral view; E. Shell in apertural view; F. Shell in ventral view; G–I. Specimen LINE-SCSLH-20240601005, low-conic; G. Shell in lateral view; H. Shell in apical view; I. Shell in ventral view. J, K. Specimen LINE-SCSMJ-20240501004, low-conic. J. Shell in apertural view; K. Shell in lateral view; L. Shell in apertural view, specimen LINE-SCSAL-20240601001, small subadult low-conic. with 3–4 folds. The columella bears 4–5 plicate dentates (Fig. 4A, E, F, I, J). Internally, the shell displays a pearly luster accompanied by distinct spiral lirae. Radula. Radula rhipidoglossate, radular formula n × 5 × 1 × 5 × n (Fig. 6A). The central tooth with U-shaped cusp, broad triangular shaft, symmetrically flanked by eight denticles (Fig. 6B). Five lateral teeth are present on each side, each with a fold on the shaft that tightly interlocks with the shaft of the adjacent tooth, and bears 3–5 denticles on one side only. The fifth lateral tooth bears a distinct paddle-shaped cusp. Marginal teeth are narrow and sickle-shaped; the innermost 10–11 marginal teeth each bear 2–3 denticles (Fig. 6C). From the 11th to 12th marginal teeth onwards, tooth size gradually decreases, while the number of denticles increases, forming comb or feather-like structures (Fig. 6D). Type locality. Neritic zone of the South China Sea; Coral reef. Measurements. Shell height 12.9–27.8 mm, shell width 14.0–24.9 mm, ellipticity 1.56E+08–4.45E+10, Normalized Avg Curvature 0.055–0.46, sphericity 0.69–0.79, (N = 17). (Details are shown in Suppl. material 1: table S3). Remarks. The genus Trochus is widely distributed across coral reef habitats throughout the Indo-West Pacific. Based on its conical shell, falsely umbilicate and radula morphology, T. nanhai sp. nov. is assigned to the genus Trochus. Due to its 273 ZooKeys 1264: 265–280 (2025), DOI: 10.3897/zookeys.1264.167854 Peng-Jin Zhu et al.: New species of genus Trochus coral reef habitat, the shell surface is often encrusted with crustose coralline algae, which obscures key morphological features and makes species identification more difficult. Upon laboratory examination, the elate-conic specimens, characterized by beaded spiral ridges, were found to resemble T. calcaratus. Although the morphological descriptions and illustrations are outdated, the species can still be distinguished based on the original descriptions, illustrations, and figures provided by Tryon et al. (1898) and Herbert (1996). Trochus nanhai sp. nov. differs from T. calcaratus in having fewer whorls (6–7 vs. 9), a base bearing densely granose lirae (11–12 vs. 6–7), and fewer peripheral pustules (12–15 vs. up to 28 on the body whorl). Comparisons with available image resources further reveal that T. nanhai sp. nov. possesses fewer but more pronounced and sharply defined pustules along the whorl periphery (Suppl. material 1: fig. S1A–C). Similar characters, particularly the number and prominence of knob-like structures on the shell base, have also been used as reliable diagnostic features for distinguishing Trochus species (Sawayama et al. 2022). Notably, T. nanhai sp. nov. lacks the fistulous or perforated peripheral tubercles and spiniform tubulose structures that are present in T. calcaratus. The subadult shell of the new species resembles that of the type species, T. maculatus. However, in T. maculatus, bears 6–8 spiral beaded liræ on each whorl, in contrast to the 4 regular spiral rows of uniform granules on each whorl observed in the new species. The radula of Trochus species has also been poorly described in previous studies (Fasila and Vinod 2024). In the present study, however, the marginal teeth of T. nanhai sp. nov. are more clearly defined: the first 10–11 marginal teeth are sickle-shaped, each bearing 2–3 denticles. Detailed morphological differences between T. nanhai sp. nov., T. sacellum, T. calcaratus, and the phylogenetically related T. stellatus are provided in Suppl. material 1: table S2. Trochus parvus sp. nov. https://zoobank.org/95BCDB2D-FEB3-41D7-9736-DFE358687E48 Etymology. The specific epithet “parvus” is derived from the Latin, meaning “small”, and refers to the relatively diminutive shell size of the new species, which is a remarkable difference from other species in this genus. Material examined. Holotype: LINE-SCSZQ-20240531002, Complete specimen, deposited in the Laboratory of Intertidal Ecophysiology, Ocean University of China (OUC), Qingdao, China (Suppl. material 1). Paratype: LINE-SCSMJ-20240501007, Complete specimen, same location as holotype (Suppl. material 1). Description. Shell: Small in size, conical, with an acute apex. The shell surface bears prominent reddish-brown longitudinal stripes that taper into spots toward the base; the apex is typically red. Composed of 6 planulate whorls, with 3–4 spiral rows of closely arranged granules (Fig. 5A–D, F–H). These granules are rounded, bead-like, or slightly compressed, and the upper whorls are smaller than those on the lower whorls. The periphery of the whorls bears a spiral ridge composed of prominent, evenly spaced pustules. The body whorl is sculptured with compact, nearly quadrate, flattened beads, forming a rounded profile. The base is slightly concave, with 7–8 concentric granulose lirae, separated by interstices as wide as the ridges (Fig. 5E). The columella is oblique, bearing 3–4 closely packed plicate-dentate, forming a false umbilicus. The inner lip contains 4 folds (Fig. 5A, E, F). 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Link: https://doi.org/10.3897/zookeys.1264.167854.suppl1