Eight new mitogenomes clarify the phylogenetic relationships of within the caenogastropod phylogenetic framework

Alison R. Irwin a, b, *, Ellen E. Strong c , Yasunori Kano d , Elizabeth M. Harper e , Suzanne T. Williams a

a Department of Life Sciences, Natural History Museum, Cromwell Rd, London, SW7 5BD, United Kingdom b School of Biological Sciences, University of Bristol, 24 Tyndall Ave, Bristol, BS8 1TQ, United Kingdom c Department of Zoology, National Museum of Natural History, Smithsonian Institution, 10th St. & Constitution Ave. NW, Washington DC 20560, United States d Department of Marine Ecosystems Dynamics, Atmosphere and Research Institute, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8564, e Department of Earth Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EQ, United Kingdom

*Corresponding author: Alison Irwin

Email: Alison Irwin: [email protected] Suzanne Williams: [email protected] Ellen Strong: [email protected] Yasunori Kano: [email protected] Elizabeth Harper: [email protected]

Declarations of interest: none Supplementary Material 1. List of published sequences used in this study with name and authority, mitogenome length, GenBank Accession number and publication reference, with complete reference list below table. Details for new sequences are in Table 2. Taxa used as outgroups in analyses are highlighted (bold), and superscript numbers mark (1) 18S and (2) 28S sequences included in mixed mitochondrial and nuclear gene trees, and (3) species name updated based on nomenclatural decisions in WoRMS (May 2020). The name chui is in MolluscaBase as a taxon inquirendum, described as a (Paracampeloma chui).

Length GenBank Higher taxon Species name Reference (bp) Acc. no. Ifremeria nautilei Bouchet & Warén, 15,664 NC_024642 Osca et al. (2014) , 1991 Abyssochryssoidea Provanna sp. Dall, 1918 16,183 KM675481 T. Xu et al. (2016) Caenogastropoda, maculata Perry, 1810 15,516 NC_027503 Yang et al. (2016) , Caenogastropoda, (Reeve, 1856) 16,640 NC_037691 J. Guo et al. (2017) Architaenioglossa, Ampullarioidea Caenogastropoda, martensianus Möllendorff, Architaenioglossa, 15,308 MH700493 Xie et al. (2019) 1874 Caenogastropoda, Architaenioglossa, Viviparus chui Yen, 1937 16,392 NC_035733 Wang et al. (2017) Caenogastropoda, Nguyen et al. Cerithidea obtusa (Lamarck, 1822) 15,708 NC_039951 Cerithioidea (2018) Caenogastropoda, , chinensis (Linnaeus, 1758) 8,530 EU827193 Cunha et al. (2009) Calyptraeoidea Caenogastropoda, tigris Linnaeus, 1758 16,177 MK783263 Pu et al. (2019) Littorinimorpha, Fukumori et al. annulus (Linnaeus, 1758) 16,087 LC469295 (2019) Marques et al. saxatilis (Olivi, 1792) 16,887 NC_030595 Caenogastropoda, (2017) Winnepenninckx Littorinimorpha, (Olivi, 1792)1 1,826 Y11751 et al. (1998) Littorina saxatilis (Olivi, 1792)2 1,464 HE590811 Reid et al. (2012) Caenogastropoda, Littorinimorpha, hebraeus (Martyn, 1786) 15,384 NC_028002 Osca et al. (2015) Naticoidea Márquez, gigas (Linnaeus, 1758)3 15,461 NC_024932 et al. (2016) Aliger gigas (Linnaeus, 1758)1, 3 638 GU198749 Spade et al. (2010)

Lambis (Linnaeus, 1758) 15,481 MH115428 Jiang et al. (2019) Caenogastropoda, Littorinimorpha, (Linnaeus, 1758)1 1,887 HQ833996 Zou et al. (2011) Stromboidea, chiragra (Linnaeus, 1758) 15,460 MH122656 Jiang et al. (2019)

Conomurex luhuanus (Linnaeus, 1758) 15,799 NC_035726 Zhao et al. (2018) Criscione and luhuanus (Linnaeus, 1758)2 1,373 KC110029 Ponder (2013) Caenogastropoda, Littorinimorpha, exutus (Reeve, 1842) 16,043 MK327366 M. Xu et al. (2019) Stromboidea, parthenopeus (Salis 15,270 NC_013247 Cunha et al. (2009) Marschlins, 1793) Caenogastropoda, echinophora (Linnaeus, Littorinimorpha, 15,388 NC_028003 Osca et al. (2015) 1758) lampas (Linnaeus, 1758) 15,405 NC_037188 Cho et al. (2017) Peretolchina et al. Korotnewia korotnevi (Lindholm, 1909)3 15,171 KY697389 (2020) Caenogastropoda, Littorinimorpha, hupensis Gredler, 1881 15,182 NC_013073 Li and Zhou (2009) antipodarum (Gray, Neiman et al. 15,110 NC_020790 1843) (2010) tulipa (Rousseau in Chenu, Rawlings et al. 15,078 NC_014585 Caenogastropoda, 1843) (2010) Littorinimorpha, Ceraesignum maximum (G. B. Sowerby Rawlings et al. 15,578 NC_014583 I, 1825) (2010) Caenogastropoda, borneensis (G. B. Sowerby 15,556 KT211493 Sung et al. (2016) , II, 1864) Babyloniidae Babylonia lutosa (Lamarck, 1816) 15,346 NC_028628 Xiong et al. (2015) Caenogastropoda, Jónsson et al. undatum Linnaeus, 1758 15,265 NC_040940 Neogastropoda, (2019) Buccinoidea clavigera (Küster, 1860) 15,285 NC_010090 Ki et al. (2010) Caenogastropoda, Clionella kraussii (E. A. Smith, 1877) 15,760 MH308390 Uribe et al. (2018) Neogastropoda, tribblei Walls, 1977 15,570 NC_027957 Barghi et al. (2016) Caenogastropoda, Zhong et al. Neogastropoda, trapa Röding, 1798 15,408 MN462589 (2019b) Muricoidea Caenogastropoda, McComish et al. Neogastropoda, northlandica Hart, 1995 15,354 NC_014403 (2010) cancellata (Linnaeus, 1767) 16,648 NC_013241 Cunha et al. (2009)

Neptuneopsis gilchristi G. B. Sowerby Harasewych et al. 15,312 MN125492 Caenogastropoda, III, 1898 (2019) Neogastropoda, olla (Linnaeus, 1758) 15,375 NC_013245 Cunha et al. (2009) Zhong et al. melo (Lightfoot, 1786) 15,721 MN462590 (2019a) Z. Guo et al. Vetigastropoda Haliotis iris Gmelin, 1791 17,131 NC_031361 (2019)

References

Barghi, N., Concepcion, G.P., Olivera, B.M., Lluisma, A.O., 2016. Characterization of the complete mitochondrial genome of Conus tribblei Walls, 1977. Mitochondrial DNA A 27, 4451 –4452. https://doi.org/10.3109/19401736.2015.1089566.

Cho, I.-Y., Kim, K.-Y., Yi, C.H., Kim, I.H., Jung, Y.-H., Hwang, S.-J., Bae, J., Yoon, M., Kim, M.-S., 2017. Full-length mitochondrial genome of the triton trumpet (Littorinimorpha: ). Mitochondrial DNA B 2, 759–760. https://doi.org/10.1080/23802359.2017.1398610.

Criscione, F., Ponder, W.F., 2013. A phylogenetic analysis of rissooidean and cingulopsoidean families (: Caenogastropoda). Mol. Phylogen. Evol. 66, 1075–1082. https://doi.org/10.1016/j.ympev.2012.11.026.

Cunha, R.L., Grande, C., Zardoya, R., 2009. Neogastropod phylogenetic relationships based on entire mitochondrial genomes. BMC Evol. Biol. 9, 210. https://doi.org/10.1186/1471-2148-9- 210.

Fukumori, H., Itoh, H., Irie, T., 2019. The mitochondrial genome of the gold-ringed cowry (: Gastropoda: ) determined by whole-genome sequencing. Mitochondrial DNA B 4, 2305–2307. https://doi.org/10.1080/23802359.2019.1627946.

Guo, J., Yang, H., Zhang, C., Xue, H., Xia, Y., Zhang, J.E., 2017. Complete mitochondrial genome of the apple Pomacea diffusa (Gastropoda, ) with phylogenetic consideration. Mitochondrial DNA B 2, 865-867. https://doi.org/10.1080/23802359.2017.1407683.

Guo, Z., Jiang, Z., Han, L., Ding, Y., Hou, X., 2019. Characterisation of the complete mitochondrial genome of the black-footed Haliotis iris. N. Z. J. Zool. 46, 74–86. https://doi.org/10.1080/03014223.2018.1495655.

Harasewych, M., Sei, M., Wirshing, H.H., González, V.L., Uribe, J.E., 2019. The complete mitochondrial genome of Neptuneopsis gilchristi GB Sowerby III, 1898 (Neogastropoda: : Calliotectinae). 133, 67–73.

Jiang, D., Zheng, X., Zeng, X., Kong, L., Li, Q., 2019. The complete mitochondrial genome of and Lambis lambis (Gastropoda: Stromboidea): implications on the Littorinimorpha phylogeny. Scientific reports 9, 1-9. https://doi.org/10.1038/s41598-019- 54141-x.

Jónsson, Z.O., Pálsson, S., Westfall, K.M., Magnúsdóttir, H., Goodall, J., Ornolfsdottir, E.B., 2019. The mitochondrial genome of common (Neogastropoda: ). Mitochondrial DNA B 4, 457–459. https://doi.org/10.1080/23802359.2018.1545534.

Ki, J.S., Lee, Y.M., Jung, S.O., Horiguchi, T., Cho, H.S., Lee, J.S., 2010. Mitochondrial genome of clavigera (Mollusca: Gastropoda): Affirmation of the conserved, ancestral gene pattern within the mollusks. Mol. Phylogeneti. Evol. 54, 1016-1020. https://doi.org/10.1016/j.ympev.2009.12.003.

Li, S., Zhou, X., 2009. The mitochondrial genome of the , the snail intermediate host of japonicum in mainland China. Direct submission to the Genome Project NCBI record NC_013073–2009. https://www.ncbi.nlm.nih.gov/nuccore/NC_013073.

Marques, J.P., Sotelo, G., Larsson, T., Johannesson, K., Panova, M., Faria, R., 2017. Comparative mitogenomic analysis of three species of periwinkles: , L. obtusata and L. saxatilis. Marine Genomics 32, 41–47. https://doi.org/10.1016/j.margen.2016.10.006.

Márquez, E.J., Castro, E.R., Alzate, J.F., 2016. Mitochondrial genome of the endangered marine gastropod gigas Linnaeus, 1758 (Mollusca: Gastropoda). Mitochondrial DNA A 27, 1516–1517. https://doi.org/10.3109/19401736.2014.953118.

McComish, B.J., Hills, S.F.K., Biggs, P.J., Penny, D., 2010. Index-free de novo assembly and deconvolution of mixed mitochondrial genomes. Genome Biol. Evol. 2, 410–424. https://doi.org/10.1093/gbe/evq029.

Neiman, M., Hehman, G., Miller, J.T., Logsdon Jr, J. M., Taylor, D.R., 2010. Accelerated mutation accumulation in asexual lineages of a . Mol. Biol. Evol. 27, 954-963. https://doi.org/10.1093/molbev/msp300.

Nguyen, D.H., Lemieux, C., Turmel, M., Nguyen, V.D., Mouget, J.-L., Witkowski, A., Tremblay, R., Gastineau, R., 2018. Complete mitogenome of Cerithidea obtusa, the red chut-chut snail from the Cần Giờ in . Mitochondrial DNA B 3, 1267–1269. https://doi.org/10.1080/23802359.2018.1532832.

Osca, D., Templado, J., Zardoya, R., 2014. The mitochondrial genome of Ifremeria nautilei and the phylogenetic position of the enigmatic deep-sea Abyssochrysoidea (Mollusca: Gastropoda). Gene 547, 257–266. https://doi.org/10.1016/j.gene.2014.06.040.

Osca, D., Templado, J., Zardoya, R., 2015. Caenogastropod mitogenomics. Mol. Phylogen. Evol. 93, 118–128. https://doi.org/10.1016/j.ympev.2015.07.011.

Peretolchina, T.E., Sitnikova, T.Y., Sherbakov, D.Y., 2020. The complete mitochondrial genomes of four Baikal molluscs from the endemic family Baicaliidae (Caenogastropoda: Truncatelloida). J. Molluscan Stud., eyaa004. https://doi.org/10.1093/mollus/eyaa004.

Pu, L., Liu, H., Yang, M., Li, B., Xia, G., Shen, M., Wang, G., 2019. Complete mitochondrial genome of tiger (Linnaeus, 1758). Mitochondrial DNA B 4, 2755–2756. https://doi.org/10.1080/23802359.2019.1627933.

Rawlings, T.A., MacInnis, M.J., Bieler, R., Boore, J.L., Collins, T.M., 2010. Sessile , dynamic genomes: gene rearrangements within the mitochondrial genome of a family of caenogastropod molluscs. BMC Genomics 11, 440. https://doi.org/10.1186/1471-2164-11- 440.

Reid, D.G., Dyal, P., Williams, S.T., 2012. A global molecular phylogeny of 147 periwinkle species (Gastropoda, Littorininae). Zool. Scr. 41, 125–136. https://doi.org/10.1111/j.1463- 6409.2011.00505.x.

Spade, D.J., Griffitt, R.J., Liu, L., Brown-Peterson, N.J., Kroll, K.J., Feswick, A., Glazer, R.A., Barber, D.S., Denslow, N.D., 2010. Queen (Strombus gigas) testis regresses during the reproductive season at nearshore sites in the Florida Keys. PLoS One 5, e12737. https://doi.org/10.1371/journal.pone.0012737.

Sung, C.H., Tseng, C.T., Wang, L.J., Li, Y.C., Lu, J.K., 2016. The complete mitochondrial genome of Babylonia borneensis (Gastropoda: Neogastropoda: Buccinidae). Mitochondrial DNA A 27, 3534-3535. https://doi.org/10.3109/19401736.2015.1074205.

Uribe, J.E., Zardoya, R., Puillandre, N., 2018. Phylogenetic relationships of the conoidean snails (Gastropoda: Caenogastropoda) based on mitochondrial genomes. Mol. Phylogenet. Evol. 127, 898-906. https://doi.org/10.1016/j.ympev.2018.06.037.

Wang, J.-G., Zhang, D., Jakovlić, I., Wang, W.-M., 2017. Sequencing of the complete mitochondrial genomes of eight freshwater snail species exposes pervasive paraphyly within the family (Caenogastropoda). PLoS One 12, e0181699. https://doi.org/10.1371/journal.pone.0181699.

Winnepenninckx, B.M., Reid, D.G., Backeljau, T., 1998. Performance of 18S rRNA in littorinid phylogeny (Gastropoda: Caenogastropoda). J. Mol. Evol. 47, 586–596. https://doi.org/10.1007/pl00006415.

Xie, G.-L., Köhler, F., Ouyang, S., Wu, X.-P., 2019. The first complete mitochondrial genome of a cyclophorid , with implications for architaenioglossan relationships (Mollusca, Caenogastropoda, Cyclophoroidea). Int. J. Biol. Macromol. 133, 522–528. https://doi.org/10.1016/j.ijbiomac.2019.04.138.

Xiong, G., Ma, X., Wang, X.-Q., Zhu, D.-L., Wang, L.-M., Qin, Q., 2015. The complete mitochondrial genome of the Babylonia lutosa. Mitochondrial DNA 26, 187–188. https://doi.org/10.3109/19401736.2013.873935.

Xu, M., Ye, Y., Yang, H., Xu, Z., Guo, B., Xu, K., Liu, L., Li, P., 2019. The complete mitochondrial genome of Onustus exutus (Gastropoda: Xenophoridae). Mitochondrial DNA B 4, 989–990. https://doi.org/10.1080/23802359.2019.1581586.

Xu, T., Sun, J., Chen, C., Qian, P.-Y., Qiu, J.-W., 2016. The mitochondrial genome of the deep- Provanna sp. (Gastropoda: ). Mitochondrial DNA A 27, 4026–4027. https://doi.org/10.3109/19401736.2014.1003827.

Yang, Q., Liu, S., Song, F., Li, H., Liu, J., Liu, G., Yu, X., 2016. The mitochondrial genome of (Gastropoda: Ampullariidae). Mitochondrial DNA A 27, 2895–2896. https://doi.org/10.3109/19401736.2015.1060426.

Zhao, Z.-Y., Tu, Z.-G., Cui, J., Bai, L.-R., 2018b. The complete mitochondrial genome of an endangered reef gastropods Trochus pyramis. Conserv. Genet. Resour. 10, 347–349. https://doi.org/10.1007/s12686-017-0821-2.

Zhong, S., Huang, G., Liu, Y., Huang, L., 2019a. The complete mitochondrial genome of marine gastropod (Neogastropoda: Volutoidea). Mitochondrial DNA B 4, 4161–4162. https://doi.org/10.1080/23802359.2019.1693293.

Zhong, S., Huang, L., Huang, G., Liu, Y., Wang, W., 2019b. The first complete mitochondrial genome of Murex from (Neogastropoda: ). Mitochondrial DNA B 4, 3394–3395. https://doi.org/10.1080/23802359.2019.1674726.

Zou, S., Li, Q., Kong, L., 2011. Additional gene data and increased sampling give new insights into the phylogenetic relationships of Neogastropoda, within the caenogastropod phylogenetic framework. Mol. Phylogen. Evol. 61, 425–435. https://doi.org/10.1016/j.ympev.2011.07.014.

Supplementary Material 2. Composition chi-square test performed via IQ-TREE for homogeneity of character composition. Whether the character composition deviates significantly from the overall composition is done by testing the chi2 value using the chi2-distribution with k-1 degrees of freedom (df=3). Sequences with character compositions that significantly deviate from the average composition of the alignment (p < 0.05) are highlighted in red; those that do not deviate from the average composition are highlighted in green. P-values are listed as percentages. Genes which are not available are highlighted in grey.

Table S2a. Composition chi-square test for each gene within the ‘Stromboidea’ dataset (ingroup = 8 sequences). Outgroup Littorina saxatilis is included in the alignment.

Table S2b. Composition chi-square test for each gene within the ‘Stromboidea’ dataset (ingroup = 14 sequences). Outgroup Littorina saxatilis is included in the alignment.

Table S2c. Composition chi-square test for each gene within the ‘Caenogastropoda’ dataset (ingroup = 40 sequences). Outgroup Haliotis iris is included in the alignment.

Supplementary Material 3. Details of phylogenetic analyses (Table S3a), and substitution model choice for site-homogeneous models (Table S3b).

Table S3a. Details of phylogenetic analyses under site-heterogeneous models, with Maximum Likelihood (ML) consensus tree log likelihood values. Ingroup taxon-sampling (‘Caenogastropoda’, ‘Stromboidea’ (ingroup taxa = 13, including published stromboid sequences; ingroup taxa = 8, new sequences only as 18S sequence data unavailable for , Harpago chiragra and Onustus exutus, and 28S sequences unavailable for Aliger gigas, Harpago chiragra, Lambis lambis and Onustus exutus)), sequence dataset (13, all mitochondrial protein-coding genes (PCGs); 17, mitochondrial (PCGs + rrnS + rrnL) and nuclear (28S + 18S) genes), residue types (1 & 2, nucleotides with the third codon positions removed; all, including all nucleotide bases), alignment method, masking method, substitution model (see Table S3b for model choice), and method of inference (ML or BI).

Taxon sampling (ingroup) Genes included Residues Method – Ln likelihood Tree no.

Caenogastropoda (40) 13 1 & 2 BI 1

Caenogastropoda (40) 13 1 & 2 ML 117765.379 2

Stromboidea (13) 13 all BI 3

Stromboidea (13) 13 all ML 79976.315 4

Stromboidea (13) 17 all BI 5

Stromboidea (13) 17 all ML 108499.658 6

Stromboidea (8) 17 all BI 7

Stromboidea (8) 17 all ML 83505.938 8

Stromboidea (8) 17 all BI 9

Stromboidea (8) 17 all ML 7737.833 10

Table S3b. Substitution model choice for site-homogeneous models, implementing Bayesian Inference (BI) or Maximum Likelihood (ML) analyses. Includes the best-fit empirical profile mixture according to Bayesian Information Criterion for site-heterogeneous models partitioned by gene. Substitution models for BI gene partitions were selected based on those chosen for ML, modified where necessary to include the next best-fitting models which can be implemented in MrBayes.

Caenogastropoda (ML) Caenogastropoda (BI) Stromboidea (ML) Stromboidea (BI)

Subset partition Best model – Ln likelihood Best model Best model – Ln likelihood Best model

cox1 GTR+F+I+G4 6440.844 GTR+I+G TIM2+F+I+G4 2481.06 GTR+I+G

cox2 K3P+R4 4561.405 GTR+G TIM2+F+I+G4 1308.005 GTR+I+G

atp8 TPM3u+F+I+G4 2445.899 GTR+I+G TPM3u+F+G4 658.181 GTR+G

atp6 TVM+F+I+G4 6817.444 GTR+I+G K3Pu+F+I+G4 1765.562 GTR+I+G

nad1 K3Pu+F+I+G4 9268.413 GTR+I+G HKY+F+I+G4 2721.503 HKY+I+G

nad6 TVM+F+I+G4 8073.444 GTR+I+G TPM3u+F+G4 2206.143 GTR+G

cob TIM+F+R5 9939.431 GTR+G TIM3+F+I+G4 2974.667 GTR+I+G

nad4l GTR+F+G4 3203.957 GTR+I+G TN+F+G4 993.146 GTR+G

nad4 TVM+F+R5 18155.807 GTR+G TVM+F+I+G4 5415.603 GTR+I+G

nad5 GTR+F+R5 22102.478 GTR+G TVM+F+I+G4 6528.307 GTR+I+G

cox3 TIM+F+R3 5600.755 GTR+G TN+F+I+G4 1711.242 GTR+I+G nad3 TVM+F+I+G4 3837.51 GTR+I+G HKY+F+G4 1091.058 HKY+G nad2 GTR+F+I+G4 16695.144 GTR+I+G TPM3u+F+G4 4815.107 GTR+G rrnS n/a n/a n/a GTR+F+I+G4 4524.662 GTR+I+G rrnL n/a n/a n/a GTR+F+I+G4 6625.659 GTR+I+G

18S n/a n/a n/a TNe+I 3620.302 GTR+I

28S n/a n/a n/a TIM2+F+I+G4 5103.633 GTR+I+G

Supplementary Material 4. Putative secondary structures for mitochondrial tRNAs determined for eight stromboid species. Sequences for tRNAs were identified using MITOZ and corroborated with ARWEN. Watson-Crick pairing is shown by lines and G-T pairing by dots. Red text indicates non-canonical pairings, an asterisk (*) extra or missing bases, and a question mark (?) ambiguous bases. Sequences not fully recovered for dentatus and Ministrombus variabilis are indicated, with the partial sequence noted where conserved among stromboid species. Photos included are of specimens sequenced. Alanine (A - TGC) Arginine (R - TCG) Asparagine (N - GTT) Aspartate (D - GTC) Cysteine (C - GCA)

Glutamate (E - TTC) Glutamine (Q - TTG) Glycine (G - TCC) Histidine (H - GTG) Isoleucine (I - GAT)

Leucine (L1 - TAG) Leucine (L2 - TAA) Lysine (K - TTT) Methionine (M - CAT) Phenylalanine (F - GAA)

Proline (P - TGG) Serine (S1 - TCT) Serine (S2 - AGA) Threonine (T - TGT) Tryptophan (W - TCA)

Tyrosine (Y - GTA) Valine (V - TAC)

Aporrhaidae serresiana tRNAs

GenBank: MW244817 Alanine (A - TGC) Arginine (R - TCG) Asparagine (N - GTT) Aspartate (D - GTC) Cysteine (C - GCA)

Glutamate (E - TTC) Glutamine (Q - TTG) Glycine (G - TCC) Histidine (H - GTG) Isoleucine (I - GAT)

Leucine (L1 - TAG) Leucine (L2 - TAA) Lysine (K - TTT) Methionine (M - CAT) Phenylalanine (F - GAA)

Proline (P - TGG) Serine (S1 - TCT) Serine (S2 - AGA) Threonine (T - TGT) Tryptophan (W - TCA)

Tyrosine (Y - GTA) Valine (V - TAC)

Rostellariidae cancellata tRNAs

GenBank: MW244822 Alanine (A - TGC) Arginine (R - TCG) Asparagine (N - GTT) Aspartate (D - GTC) Cysteine (C - GCA)

Glutamate (E - TTC) Glutamine (Q - TTG) Glycine (G - TCC) Histidine (H - GTG) Isoleucine (I - GAT)

Leucine (L1 - TAG) Leucine (L2 - TAA) Lysine (K - TTT) Methionine (M - CAT) Phenylalanine (F - GAA)

Proline (P - TGG) Serine (S1 - TCT) Serine (S2 - AGA) Threonine (T - TGT) Tryptophan (W - TCA)

Tyrosine (Y - GTA) Valine (V - TAC)

Seraphsidae terebellum tRNAs

GenBank: MW244821 Alanine (A - TGC) Arginine (R - TCG) Asparagine (N - GTT) Aspartate (D - GTC) Cysteine (C - GCA)

Glutamate (E - TTC) Glutamine (Q - TTG) Glycine (G - TCC) Histidine (H - GTG) Isoleucine (I - GAT)

Leucine (L1 - TAG) Leucine (L2 - TAA) Lysine (K - TTT) Methionine (M - CAT) Phenylalanine (F - GAA) Partial sequence recovered: No conserved sequence recovered ATTCATTTTTGGGGTATGAA CCCAACAGCTTATTATTTAG CTTATTTTACA

Proline (P - TGG) Serine (S1 - TCT) Serine (S2 - AGA) Threonine (T - TGT) Tryptophan (W - TCA) Partial sequence recovered: TGTAGTTTAATTAGAATACT AGCATTGGGA

Tyrosine (Y - GTA) Valine (V - TAC) Partial sequence recovered: AAAAATATAGCATAATAGTA ATGCATCTCACTTACATTG Strombidae AGAAC Ministrombus variabilis tRNAs

GenBank: MW244824 Alanine (A - TGC) Arginine (R - TCG) Asparagine (N - GTT) Aspartate (D - GTC) Cysteine (C - GCA)

Glutamate (E - TTC) Glutamine (Q - TTG) Glycine (G - TCC) Histidine (H - GTG) Isoleucine (I - GAT)

Leucine (L1 - TAG) Leucine (L2 - TAA) Lysine (K - TTT) Methionine (M - CAT) Phenylalanine (F - GAA)

Proline (P - TGG) Serine (S1 - TCT) Serine (S2 - AGA) Threonine (T - TGT) Tryptophan (W - TCA)

Tyrosine (Y - GTA) Valine (V - TAC)

Strombidae tRNAs

GenBank: MW244819 Alanine (A - TGC) Arginine (R - TCG) Asparagine (N - GTT) Aspartate (D - GTC) Cysteine (C - GCA)

Glutamate (E - TTC) Glutamine (Q - TTG) Glycine (G - TCC) Histidine (H - GTG) Isoleucine (I - GAT)

Leucine (L1 - TAG) Leucine (L2 - TAA) Lysine (K - TTT) Methionine (M - CAT) Phenylalanine (F - GAA)

Proline (P - TGG) Serine (S1 - TCT) Serine (S2 - AGA) Threonine (T - TGT) Tryptophan (W - TCA)

Tyrosine (Y - GTA) Valine (V - TAC) Partial sequence recovered: AAAAATATAGCATAATAGTA ATGCATCTCACTTACACTGA GAACATGCTGAAAATATC Strombidae Tridentarius dentatus tRNAs

GenBank: MW244820 Alanine (A - TGC) Arginine (R - TCG) Asparagine (N - GTT) Aspartate (D - GTC) Cysteine (C - GCA)

Glutamate (E - TTC) Glutamine (Q - TTG) Glycine (G - TCC) Histidine (H - GTG) Isoleucine (I - GAT)

Leucine (L1 - TAG) Leucine (L2 - TAA) Lysine (K - TTT) Methionine (M - CAT) Phenylalanine (F - GAA)

Proline (P - TGG) Serine (S1 - TCT) Serine (S2 - AGA) Threonine (T - TGT) Tryptophan (W - TCA)

Tyrosine (Y - GTA) Valine (V - TAC)

Struthiolariidae papulosa tRNAs

GenBank: MW244818 Alanine (A - TGC) Arginine (R - TCG) Asparagine (N - GTT) Aspartate (D - GTC) Cysteine (C - GCA)

Glutamate (E - TTC) Glutamine (Q - TTG) Glycine (G - TCC) Histidine (H - GTG) Isoleucine (I - GAT)

Leucine (L1 - TAG) Leucine (L2 - TAA) Lysine (K - TTT) Methionine (M - CAT) Phenylalanine (F - GAA)

Proline (P - TGG) Serine (S1 - TCT) Serine (S2 - AGA) Threonine (T - TGT) Tryptophan (W - TCA)

Tyrosine (Y - GTA) Valine (V - TAC)

Xenophoridae japonica tRNAs

GenBank: MW244823 Supplementary Material 5. Details of mitochondrial genomes for eight gastropods. Genes are listed in order (identical for all taxa), beginning with cox1. Maximum size difference for each gene (Size Range), position of initial base pair (start), position of final base pair (stop), length of gene in nucleotides (L(nt)), length of gene in amino acids (L(aa)), initiation and termination codons (In./Term.), longest non-coding region (NCR). Standard abbreviations are used for protein-coding genes and both one and three letter abbreviations are given for tRNAs, along with the codon used. Initiation codons other than ATG (blue), truncated terminations codons TA (red) and genes with overlapping sequences (yellow) are marked. Mitogenomes are complete except for Ministrombus variabilis. Regions of the mitogenome could not be recovered where the transcriptomic data (Ministrombus variabilis and Tridentarius dentatus) were poor, leading to uncertain base calls (indicated in grey). Schematic diagrams for tRNAs are given in Suppl. Mat. 4; see Fig. 2 for Strombus pugilis.

Aporrhaidae Strombidae Strombidae Strombidae Xenophoridae Aporrhais serresiana Varicospira cancellata Ministrombus variabilis Strombus pugilis Tridentarius dentatus Struthiolaria papulosa Xenophora japonica Total length (bp) 15,455 15,864 15,478 15,292* 15,809 15,500 15,475 15,684 Gene Size Range (bp) Start Stop L(nt) L(aa) In./Term. Start Stop L(nt) L(aa) In./Term. Start Stop L(nt) L(aa) In./Term. Start Stop L(nt) L(aa) In./Term. Start Stop L(nt) L(aa) In./Term. Start Stop L(nt) L(aa) In./Term. Start Stop L(nt) L(aa) In./Term. Start Stop L(nt) L(aa) In./Term. cox1 0 1 1,536 1,536 512 ATG/TAA 1 1,536 1,536 512 ATG/TAA 1 1,536 1,536 512 ATG/TAA 1 1,536 1,536 512 ATG/TAA 1 1,536 1,536 512 ATG/TAA 1 1,536 1,536 512 ATG/TAA 1 1,536 1,536 512 ATG/TAA 1 1,536 1,536 512 ATG/TAA cox2 0 1,560 2,246 687 229 ATG/TAA 1,564 2,250 687 229 ATG/TAA 1,573 2,259 687 229 ATG/TAA 1,556 2,242 687 229 ATG/TAA 1,556 2,242 687 229 ATG/TAA 1,553 2,239 687 229 ATG/TAA 1,557 2,243 687 229 ATG/TAA 1,570 2,256 687 229 ATG/TAA trnD (GUC) - Asp 4 2,244 2,315 72 2,248 2,317 70 2,258 2,325 68 2,240 2,309 70 2,240 2,309 70 2,237 2,306 70 2,241 2,311 71 2,254 2,324 71 atp8 0 2,315 2,473 159 53 ATG/TAA 2,318 2,476 159 53 ATG/TAA 2,326 2,484 159 53 ATG/TAA 2,309 2,467 159 53 ATG/TAA 2,309 2,467 159 53 ATG/TAA 2,306 2,464 159 53 ATG/TAA 2,311 2,469 159 53 ATG/TAA 2,324 2,482 159 53 ATG/TAA atp6 0 2,479 3,174 696 232 ATG/TAA 2,479 3,174 696 232 ATG/TAA 2,487 3,182 696 232 ATG/TAA 2,471 3,166 696 232 ATG/TAA 2,472 3,167 696 232 ATG/TAA 2,467 3,162 696 232 ATG/TAG 2,475 3,170 696 232 ATG/TAG 2,485 3,180 696 232 ATG/TAA trnM (CAU) - Met 3 3,228 3,296 69 3,208 3,273 66 3,223 3,289 67 n/a n/a n/a 3,212 3,279 68 3,204 3,271 68 3,216 3,282 67 3,216 3,284 69 trnY (GUA) - Tyr 3 3,307 3,375 69 3,275 3,343 69 3,313 3,379 67 3,294 3,362 69 3,295 3,364 70 3,291 3,358 68 3,285 3,353 69 3,285 3,354 70 trnC (GCA) - Cys 2 3,376 3,442 67 3,345 3,410 66 3,383 3,447 65 3,364 3,428 65 3,367 3,431 65 3,360 3,425 66 3,357 3,422 66 3,356 3,422 67 trnW (UCA) - Trp 1 3,443 3,508 66 3,412 3,477 66 3,449 3,514 66 3,430 3,496 67 3,433 3,499 67 3,427 3,493 67 3,424 3,489 66 3,424 3,489 66 trnQ (UUG) - Gln 2 3,507 3,574 68 3,475 3,541 67 3,512 3,578 67 3,494 3,560 67 3,497 3,563 67 3,491 3,557 67 3,487 3,553 67 3,488 3,553 66 trnG (UCC) - Gly 4 3,584 3,652 69 3,548 3,615 68 3,580 3,649 70 3,573 3,639 67 3,564 3,630 67 3,563 3,629 67 3,558 3,626 69 3,554 3,619 66 trnE (UUC) - Glu 4 3,659 3,730 72 3,614 3,683 70 3,648 3,716 69 3,639 3,710 72 3,628 3,700 73 3,630 3,697 68 3,626 3,696 71 3,620 3,690 71 rrnS 27 3,808 4,686 879 3,767 4,659 893 3,788 4,665 878 3,790 4,680 891 3,783 4,687 905 3,788 4,680 893 3,774 4,656 883 3,758 4,646 889 trnV (UAC) - Val 4 4,684 4,751 68 4,658 4,723 66 4,663 4,729 67 4,685 4,751 67 4,654 4,725 72 4,644 4,713 70 rrnL 28 4,730 6,145 1,416 4,702 6,098 1,397 4,708 6,108 1,401 4,725 6,140 1,416 4,730 6,154 1,425 4,726 6,150 1,425 4,704 6,124 1,421 4,690 6,094 1,405 trnL (UAG) - Leu 2 6,120 6,190 71 6,073 6,143 71 6,084 6,152 69 6,115 6,185 71 6,130 6,198 69 6,125 6,195 71 6,100 6,168 69 6,070 6,138 69 trnL (UAA) - Leu 2 6,192 6,260 69 6,146 6,216 71 6,157 6,227 71 6,193 6,261 69 6,211 6,279 69 6,206 6,276 71 6,177 6,247 71 6,149 6,219 71 nad1 1 6,262 7,203 942 314 ATG/TAA 6,217 7,158 942 314 ATG/TAA 6,227 7,166 942 314 ATG/TA 6,263 7,204 942 314 ATG/TAA 6,281 7,222 942 314 ATG/TAA 6,277 7,218 942 314 ATG/TAA 6,248 7,189 942 314 ATG/TAA 6,222 7,163 942 314 ATG/TAA trnP (UGG) - Pro 5 7,212 7,283 72 7,171 7,237 67 7,168 7,236 69 7,229 7,298 70 7,231 7,301 71 7,197 7,266 70 7,174 7,241 68 nad6 6 7,284 7,787 504 168 ATG/TAA 7,239 7,742 504 168 ATG/TAA 7,238 7,744 507 169 ATG/TAA 7,282 7,788 507 169 ATG/TAA 7,302 7,808 507 169 ATG/TAA 7,305 7,811 507 169 ATG/TAA 7,267 7,773 507 169 ATG/TAA 7,243 7,752 510 170 ATG/TAG cob 0 7,822 8,961 1,140 380 ATG/TAA 7,749 8,888 1,140 380 ATG/TAA 7,758 8,897 1,140 380 ATG/TAA 7,799 8,938 1,140 380 7,819 8,958 1,140 380 ATG/TAA 7,827 8,966 1,140 380 ATG/TAA 7,791 8,930 1,140 380 ATG/TAA 7,787 8,926 1,140 380 ATG/TAG trnS (UGA) - Ser 3 8,972 9,038 67 8,890 8,954 65 8,909 8,975 67 8,946 9,013 68 8,966 9,031 66 8,974 9,041 68 8,941 9,005 65 8,932 8,997 66 trnT (UGU) - Thr 5 9,072 9,141 70 8,966 9,037 72 8,981 9,050 70 9,022 9,088 67 9,049 9,118 70 9,051 9,118 68 9,025 9,096 72 9,000 9,068 69 nad4L 0 9,147 9,443 297 99 ATG/TAA 9,050 9,346 297 99 ATG/TAA 9,057 9,353 297 99 ATG/TAG 9,096 9,392 297 99 ATG/TAG 9,127 9,423 297 99 ATG/TAG 9,128 9,424 297 99 ATG/TAG 9,106 9,402 297 99 ATG/TAA 9,081 9,377 297 99 ATG/TAG nad4 0 9,446 10,810 1,365 455 ATT/TAA 9,349 10,713 1,365 455 ATA/TAA 9,356 10,720 1,365 455 ATT/TAG 9,395 10,759 1,365 455 GTT/TAA 9,426 10,790 1,365 455 ATT/TAG 9,427 10,791 1,365 455 ATT/TAG 9,405 10,769 1,365 455 ATT/TAA 9,380 10,744 1,365 455 ATT/TAA trnH (GUG) - His 5 10,827 10,890 64 10,717 10,785 69 10,728 10,792 65 10,761 10,857 67 10,797 10,862 66 10,793 10,859 67 10,785 10,848 64 10,775 10,840 66 nad5 3 10,894 12,618 1,725 575 TTG/TAA 10,785 12,512 1,728 576 ATG/TAA 10,793 12,520 1,728 576 ATG/TAA 10,857 12,554 1,728 576 ATG/TAA 10,863 12,590 1,728 576 ATG/TAA 10,859 12,586 1,728 576 ATG/TAG 10,849 12,573 1,725 575 ATG/TAA 10,841 12,568 1,728 576 ATG/TAA trnF (GAA) - Phe 3 12,628 12,697 70 12,561 12,631 71 12,535 12,602 68 12,613 12,681 69 12,604 12,672 69 12,585 12,653 69 12,576 12,646 71 cox3 0 12,761 13,540 780 260 ATG/TAA 13,101 13,880 780 260 ATG/TAA 12,767 13,546 780 260 ATG/TAA 12,596 13,375 780 260 ATG/TAA 13,118 13,897 780 260 ATG/TAG 12,788 13,567 780 260 ATG/TAA 12,747 13,526 780 260 ATG/TAA 13,035 13,814 780 260 ATG/TAA trnK (UUU) - Lys 6 13,551 13,625 75 13,891 13,966 76 13,586 13,655 70 13,414 13,485 72 13,936 14,005 70 13,599 13,668 70 13,540 13,614 75 13,838 13,911 74 trnA (UGC) - Ala 4 13,645 13,711 67 13,973 14,039 67 13,681 13,748 68 13,510 13,580 71 14,021 14,091 71 13,693 13,763 71 13,641 13,708 68 13,916 13,982 67 trnR (UCG) - Arg 4 13,748 13,816 69 14,041 14,110 70 13,751 13,819 69 13,589 13,657 69 14,104 14,174 71 13,790 13,859 70 13,732 13,804 73 13,983 14,051 69 trnN (GUU) - Asn 4 13,817 13,886 70 14,119 14,189 71 13,845 13,911 67 13,668 13,736 69 14,186 14,254 69 13,874 13,940 67 13,822 13,892 71 14,056 14,124 69 trnI (GAU) - Ile 4 13,903 13,970 68 14,200 14,267 68 13,931 13,999 69 13,738 13,804 67 14,258 14,326 69 13,942 14,008 67 13,924 13,994 71 14,129 14,195 67 nad3 0 13,972 14,325 354 118 ATG/TAG 14,377 14,730 354 118 ATG/TAA 14,001 14,354 354 118 ATG/TAG 13,806 14,159 354 118 ATG/TAA 14,328 14,681 354 118 ATG/TAA 14,010 14,363 354 118 ATG/TAA 13,997 14,350 354 118 ATG/TAG 14,200 14,553 354 118 ATG/TAA trnS (GCU) - Ser 2 14,324 14,391 68 14,734 14,801 68 14,353 14,420 68 14,162 14,229 68 14,680 14,749 70 14,366 14,433 68 14,349 14,416 68 14,556 14,625 70 nad2 3 14,392 15,450 1,059 353 ATG/TAA 14,802 15,857 1,056 352 ATG/TAA 14,421 15,478 1,058 352 ATG/TA 14,230 15,288 1,059 353 ATG/TAA 14,749 15,807 1,059 353 ATG/TAG 14,434 15,492 1,059 353 ATG/TAA 14,417 15,475 1,059 353 ATG/TAA 14,625 15,683 1,059 353 ATG/TAA Longest NCR 406 12,698 12,760 63 12,632 13,100 469 12,603 12,766 164 12,682 13,117 436 12,673 12,787 115 12,654 12,746 93 12,647 13,034 388

Supplementary Material 6. Results from all phylogenetic analyses in this study. Phylogenies were produced by ML as implemented in IQ-TREE or Bayesian Inference as implemented in MrBayes. Major taxon groups are identified by blocks of colour, with Bayesian Inference posterior probabilities or Maximum Likelihood ultrafast bootstrap values supporting those groups indicated in the top right of the block. Stromboidea is here defined as including Xenophoridae (highlighted in red font). Trees 5 and 6 (highlighted in grey) recovered the most relationships corroborated by morphological data. Outgroups are removed from trees (Trees 1, 2, Haliotis iris NC_031361; Trees 3–10; Littorina saxatilis NC_030595, Y1175.1, HE590811) for ease of reading. See Suppl. Mat. 1 for GenBank Accession numbers; Table 4 for summary of analysis methods and results.

Cerithidea obtusa Cerithioidea Pomacea maculata Ampullarioidea 1 Architaenioglossa 0.84 Cyclophorus martensianus Cyclophoroidea Viviparus chui Viviparoidea PP = 1.0 1 Korotnewia korotnevi 1 Truncatelloidea Oncomelania hupensis Littorinimorpha PP = 1.0 1 Naticoidea 1 Littorina saxatilis Littorinoidea 1 Vermetoidea 0.63 Ceraesignum maximum 1 Ifremeria nautilei Abyssochrysoidea 1 Provanna sp. 1 Onustus exutus Xenophoridae Stromboidea Littorinimorpha 1 Xenophora japonica PP = 1.0 1 Struthiolaria papulosa Struthiolariidae 1 1 Aporrhais serresiana Aporrhaidae Terebellum terebellum Seraphsidae 1 Varicospira cancellata Rostellariidae 0.97 1 Aliger gigas Strombus pugilis 1 Conomurex luhuanus 0.7 1 1 Ministrombus variabilis Strombidae 0.7 Tridentarius dentatus 1 Lambis lambis Harpago chiragra 1 Monetaria annulus Cypraea tigris Cypraeoidea 0.68 0.68 Calyptraeoidea (Volutoidea) Neogastropoda 0.68 1 1 Tonnoidea Charonia lampas 0.98 1 Neptuneopsis gilchristi 1 Volutidae (Volutoidea) 1 Melo melo Murex trapa Muricoidea 1 1 Babylonia lutosa Babyloniidae 0.94 Conus tribblei Conoidea 0.67 Buccinum undatum Buccinoidea Amalda northlandica Olivoidea 0.25 Tree 1 Caenogastropoda(40)_13-gene_nt(3rd codon removed)_BI Cerithidea obtusa Cerithioidea Pomacea maculata Ampullarioidea 99 Architaenioglossa 89 Cyclophorus martensianus Cyclophoroidea B/S = 99% Viviparus chui Viviparoidea 100 100 Korotnewia korotnevi Truncatelloidea Littorinimorpha Hypsogastropoda Oncomelania hupensis B/S = 98% 100 Naticarius hebraeus Naticoidea 98 Littorina saxatilis Littorinoidea Calyptraea chinensis Calyptraeoidea Ifremeria nautilei 90 100 Abyssochrysoidea Provanna sp. Ceraesignum maximum 100 Vermetoidea Littorinimorpha Eualetes tulipa Onustus exutus Stromboidea 100 Xenophoridae 100 Xenophora japonica B/S = 100% 90 99 Struthiolaria papulosa Struthiolariidae 100 Aporrhais serresiana Aporrhaidae Terebellum terebellum Seraphsidae 100 Varicospira cancellata Rostellariidae 75 100 Aliger gigas Strombus pugilis 100 Conomurex luhuanus Strombidae 50 93100 Ministrombus variabilis 63 Tridentarius dentatus 98 Lambis lambis Harpago chiragra 100 Monetaria annulus Cypraeoidea Cypraea tigris 50 Bivetiella cancellata Cancellariidae (Volutoidea) Neogastropoda Monoplex parthenopeus B/S = 50% 50 100 100 Galeodea echinophora Tonnoidea Charonia lampas 88 Neptuneopsis gilchristi 100 98 Cymbium olla Volutidae (Volutoidea) 99 Melo melo Murex trapa Muricoidea 100 96 Babylonia lutosa Babyloniidae 8 4 Conus tribblei Conoidea 67 Buccinum undatum Buccinoidea Amalda northlandica Olivoidea 0.25 Tree 2 Caenogastropoda(40)_13-gene_nt(3rd codon removed)_ML Tree 3 Tree 4 Stromboidea(13)_13-gene_nt(all bases)_BI Stromboidea(13)_13-gene_nt(all bases)_ML (all mitochondrial protein-coding genes) (all mitochondrial protein-coding genes)

Onustus exutus 1 Onustus exutus Xenophoridae 100 Xenophoridae PP = 100% 1 Xenophora japonica 100 Xenophora japonica B/S = 100% 1 Aporrhais serresiana Aporrhaidae 100 Aporrhais serresiana Aporrhaidae Struthiolaria papulosa Struthiolariidae Struthiolaria papulosa Struthiolariidae 1 0.98 Terebellum terebellum Seraphsidae Terebellum terebellum Seraphsidae Varicospira cancellata Rostellariidae 8 6 Varicospira cancellata Rostellariidae 1 1 Strombus pugilis Strombidae 5 9 100 Strombus pugilis Strombidae Aliger gigas B/S = 100% Aliger gigas B/S = 100% 1 100 Conomurex luhuanus Conomurex luhuanus 1 1 Ministrombus variabilis 8 4 100 Ministrombus variabilis 0.98 Tridentarius dentatus 5 0 Tridentarius dentatus 1 Lambis lambis 100 Lambis lambis Harpago chiragra Harpago chiragra

0.5 0.5

Preferred ‘Stromboidea’ dataset trees Tree 5 Tree 6 Stromboidea(13)_17-gene_nt(all bases)_BI Stromboidea(13)_17-gene_nt(all bases)_ML (all mitochondrial protein-coding genes + rrnS + rrnL + 18S + 28S) (all mitochondrial protein-coding genes + rrnS + rrnL + 18S + 28S)

1 Onustus exutus Xenophoridae 100 Onustus exutus Xenophoridae PP = 100% B/S = 100% 1 Xenophora japonica 100 Xenophora japonica 1 Aporrhais serresiana Aporrhaidae 100 Aporrhais serresiana Aporrhaidae Struthiolaria papulosa Struthiolariidae 1 Struthiolaria papulosa Struthiolariidae 1 Terebellum terebellum Seraphsidae 9 0 Terebellum terebellum Seraphsidae Varicospira cancellata Rostellariidae Varicospira cancellata Rostellariidae 1 100 Conomurex luhuanus Strombidae Conomurex luhuanus Strombidae B/S = 100% B/S = 100% 1 1 Aliger gigas 100 100 Aliger gigas Strombus pugilis Strombus pugilis 1 8 0 1 Tridentarius dentatus 100 Ministrombus variabilis 1 Ministrombus variabilis 7 5 Tridentarius dentatus 1 Lambis lambis 100 Lambis lambis Harpago chiragra Harpago chiragra

0.5 0.5

Tree 7 Tree 8 Stromboidea(8)_17-gene_nt(all bases)_BI Stromboidea(8)_17-gene_nt(all bases)_ML (all mitochondrial protein-coding genes + rrnS + rrnL + 18S + 28S) (all mitochondrial protein-coding genes + rrnS + rrnL + 18S + 28S)

1 Xenophora japonica Xenophoridae Xenophora japonica Xenophoridae 1 100 1 Aporrhais serresiana Aporrhaidae Aporrhais serresiana Aporrhaidae 1 100 1 Struthiolaria papulosa Struthiolariidae Struthiolaria papulosa Struthiolariidae 1 Terebellum terebellum Seraphsidae Terebellum terebellum Seraphsidae 1 7 0 Varicospira cancellata Rostellariidae Varicospira cancellata Rostellariidae 1 100 Strombus pugilis Strombidae Strombus pugilis Strombidae PP = 1 B/S = 1 1 100 Tridentarius dentatus Tridentarius dentatus 1 100

Ministrombus variabilis Ministrombus variabilis

0.5 0.5 Tree 9 Tree 10 Stromboidea(8)_2-gene_nt(all bases)_BI Stromboidea(8)_2-gene_nt(all bases)_ML (nuclear genes only;18S + 28S) (nuclear genes only; 18S + 28S)

Struthiolaria papulosa Struthiolariidae Struthiolaria papulosa Struthiolariidae 1 77 Xenophora japonica Xenophoridae Xenophora japonica Xenophoridae 1 77

1 Aporrhais serresiana Aporrhaidae Aporrhais serresiana Aporrhaidae

Varicospira cancellata Rostellariidae Varicospira cancellata Rostellariidae 1 99 Terebellum terebellum Seraphsidae Terebellum terebellum Seraphsidae 1 94 Strombus pugilis Strombidae Strombus pugilis Strombidae 1 PP = 1 100 PP = 1 Tridentaris dentatus Tridentaris dentatus 1 100

Ministrombus variabilis Ministrombus variabilis

0.01 0.01