Marine Biodiversity

, Volume 49, Issue 1, pp 357–371 | Cite as

Integrative systematics of Placida cremoniana (Trinchese, 1892) (Gastropoda, Heterobranchia, Sacoglossa) reveals multiple pseudocryptic species

  • Jennifer B. McCarthy
  • Patrick J. Krug
  • Ángel ValdésEmail author
Original Paper


Placida cremoniana (Trinchese, 1892) is a sacoglossan heterobranch sea slug of striking coloration, with a reported range that has increased dramatically in recent years. Described from the Mediterranean in 1892, nominal conspecifics were reported from Japan in 1959, and since the 1990s, additional populations have been reported from across the tropical Atlantic, Pacific, and Indian oceans, plus temperate areas of Japan, Australia, and Europe. This sequence of events is consistent with a dramatic range expansion by one species due to human-mediated introductions, or dispersal from tropical into temperate areas induced by recent climate change. Alternatively, the expanding range of this nominal species could, instead, reflect the gradual discovery of previously unsampled members of a global species complex. These hypotheses were tested using a combination of molecular data from three loci (COI, 16S, and H3), as well as radular morphology and external color patterns, from specimens sampled from most of the reported range. Molecular species delimitation recovered P. cremoniana as a complex of four genetically divergent species, further distinguished by consistent differences in head coloration and radular morphology. As the Mediterranean species retains the name P. cremoniana, the three new species are described here, including an Eastern Pacific endemic and two species that are sympatric across large areas of the Central and Western Pacific. Photographic records and literature reports suggest that additional species may occur in the Indian Ocean, tropical Australia, and Caribbean.


Molecular systematics Mollusca New species Species delineation Taxonomic revision 



This paper was funded by awards from the U.S. National Science Foundation (DEB-1355177 to AV, and DEB-1355190 and OCE-1130072 to PK), and by the LaKretz endowment for environmental science research at Cal State L.A. The SEM work was conducted at the California State Polytechnic University SEM laboratory supported by the U.S. National Science Foundation (NSF) grant DMR-1429674. Specimens from the Mediterranean were generously donated by our colleagues from GROC (Grup de Recerca d’Opistobranquis de Catalunya); specimens from Catalina Island were collected and provided by Brooke Peterson. Sampling in Sydney, Australia was made possible by the help and local knowledge of Nerida Wilson, and samples from Japan were generously provided by Yayoi Hirano and Cynthia Trowbridge; we gratefully acknowledge their assistance and expertise. Museum specimens were obtained from the California Academy of Sciences in San Francisco with the assistance of Liz Kools and Terry Gosliner.

Supplementary material

12526_2017_812_MOESM1_ESM.docx (641 kb)
ESM 1 (DOCX 640 kb)


  1. Alexander J, Valdés A (2013) The ring doesn’t mean a thing: molecular data suggest a new taxonomy for two Pacific species of sea hares (Mollusca: Opisthobranchia, Aplysiidae). Pac Sci 67:283–294CrossRefGoogle Scholar
  2. Baba K (1959) The family Stiligeridae from Japan (Opisthobranchia-Sacoglossa). Publ Seto Mar Biol Lab 7:327–334CrossRefGoogle Scholar
  3. Ballesteros M (1980) La presencia en las costas Catalanas de Hermaea paucirra y Hermaea cremoniana (Opisthobranchia: Sacoglossa). Pub Dep Zool Univ Barc 5:19–23Google Scholar
  4. Ballesteros MBV (2007) Lista actualizada de los opistobranquios (Mollusca: Gastropoda: Opisthobranchia) de las costas Catalanas. Spira 2:163–188Google Scholar
  5. Ballesteros MBV (2014) La obra olvidada de Siro de Fez sobre los opistobranquios Ibéricos. Spira 5:105–109Google Scholar
  6. Baums IB, Boulay JN, Polato NR, Hellberg ME (2012) No gene flow across the Eastern Pacific Barrier in the reef-building coral Porites lobata. Mol Ecol 21:5418–5433CrossRefGoogle Scholar
  7. Behrens DW (2004) Placida cremoniana. Sea Slug Forum. Accessed 28 April 2017
  8. Behrens DW, Hermosillo A (2005) Eastern Pacific nudibranchs. A guide to the opisthobranchs from Alaska to Central America. Sea Challengers, MontereyGoogle Scholar
  9. Bidgrain P (2010) Placida cremoniana (Trinchese, 1893). Southwest Indian Ocean Sea Slugs and Flatworms. Accessed 28 April 2017
  10. Burn R (1998) Order Sacoglossa. In: Beesley PL, Ross JGB, Wells A (eds) Mollusca: the southern synthesis. Fauna of Australia, Vol. 5, Part B. CSIRO Publishing, Melbourne, pp 961–974Google Scholar
  11. Caballer Gutiérrez M, Ortea J, Rivero N, Carias Tucker G, Malaquías MAE, Narciso S (2015) The opisthobranch gastropods (Mollusca: Heterobranchia) from Venezuela: an annotated and illustrated inventory of species. Zootaxa 4034:201–256CrossRefGoogle Scholar
  12. Camacho-García YE, Gosliner TM, Valdés A (2005) Guía de campo de las babosas marinas del Pacífico Este tropical. California Academy of Sciences, San FranciscoGoogle Scholar
  13. Camacho-García YE, Ornelas-Gatdula E, Gosliner TM, Valdés Á (2014) Phylogeny of the family Aglajidae (Pilsbry, 1895) (Heterobranchia: Cephalaspidea) inferred from mtDNA and nDNA. Mol Phyl Evol 71:113–126CrossRefGoogle Scholar
  14. Carlson C, Hoff PJ (2003) The opisthobranchs of the Mariana Islands. Micronesica 35:271–293Google Scholar
  15. Carmona L, Lei BR, Pola M, Gosliner TM, Valdés Á, Cervera JL (2014) Untangling the Spurilla neapolitana (Delle Chiaje, 1841) species complex: a review of the genus Spurilla Bergh, 1864 (Mollusca: Nudibranchia: Aeolidiidae). Zool J Linn Soc 170:132–154CrossRefGoogle Scholar
  16. Chang Y-W (2012) Study on the biodiversity of opisthobranchs in Taiwan and adjacent islands. Dissertation, National Sun Yat-sen University, Republic of ChinaGoogle Scholar
  17. Chichvarkhin AY, Ekimova IA, Chalenko KP, Schepetov D, Chichvarkhina OV, Valdés Á (2016) Placida babai (Mollusca: Gastropoda: Sacoglossa) from Russian waters of the Sea of Japan. Bull Russ Far East Malacol Soc 20:44–56Google Scholar
  18. Churchill CKC, Alejandrino A, Valdés Á, Foighil DÓ (2013) Parallel changes in genital morphology delineate cryptic diversification of planktonic nudibranchs. Proc R Soc Biol Sci 280:20131224CrossRefGoogle Scholar
  19. Churchill CKC, Valdés Á, Foighil DÓ (2014) Molecular and morphological systematics of neustonic nudibranchs (Mollusca: Gastropoda: Glaucidae: Glaucus), with descriptions of three new cryptic species. Invertebr Syst 28:174–195CrossRefGoogle Scholar
  20. Coleman N (2008) Nudibranchs encyclopedia: catalogue of Asia/Indo-Pacific sea slugs. Neville Coleman’s Underwater Geographic Pty Ltd., SpringwoodGoogle Scholar
  21. Colgan DJ, Ponder WF, Eggler PE (2000) Gastropod evolutionary rates and phylogenetic relationships assessed using partial 28S rDNA and histone H3 sequences. Zool Scr 29:29–63CrossRefGoogle Scholar
  22. Cortés M (2008) Placida cremoniana from the Bay of Biscay. Sea Slug Forum. Accessed 28 April 2017
  23. Cowman PF, Bellwood DR (2013) Vicariance across major marine biogeographic barriers: temporal concordance and the relative intensity of hard versus soft barriers. Proc R Soc Biol Sci 280:20131541CrossRefGoogle Scholar
  24. Edgar RC (2004) MUSCLE: multiple sequence alignment with high accuracy and high throughput. Nucleic Acids Res 32:1792–1797CrossRefGoogle Scholar
  25. Ellingson RA, Krug PJ (2016) Reduced genetic diversity and increased reproductive isolation follow population-level loss of larval dispersal in a marine gastropod. Evolution 70:18–37CrossRefGoogle Scholar
  26. Fez S (1962) Dos nuevos ascoglosos y un doto en el puerto de Valencia. Bol R Soc Esp Hist Nat (B) 60:105–112Google Scholar
  27. Fontes J, Tempera F, Wirtz P (2001) On some interesting opisthobranchs (Mollusca, Gastropoda) from the Azores. Life Mar Sci 18A:85–87Google Scholar
  28. Folmer O, Black M, Hoeh W, Lutz R, Vrijenhoek R (1994) DNA primers for amplification of mitochondrial cytochrome c oxidase subunit I from diverse metazoan invertebrates. Mol Mar Biol Biotechnol 3:294–299Google Scholar
  29. Gavagnin M, Spinella A, Crispino A, de Almeida Epifanio R, Marin A, Cimino G (1993) Chemical components of the Mediterranean ascoglossan Thuridilla hopei. Gazz Chim Ital 123:205–208Google Scholar
  30. Gavagnin M, Marin A, Mollo E, Crispino A, Villani G, Cimino G (1994) Secondary metabolites from Mediterranean Elysioidea: origin and biological role. Comp Biochem Physiol B 108:107–115CrossRefGoogle Scholar
  31. Goodheart J, Camacho-García Y, Padula V, Schrödl M, Cervera JL, Gosliner TM, Valdés Á (2015) Systematics and biogeography of Pleurobranchus Cuvier, 1804, sea slugs (Heterobranchia: Nudipleura: Pleurobranchidae). Zool J Linn Soc 174:322–362CrossRefGoogle Scholar
  32. Gosliner TM, Behrens DW, Valdés Á (2008) Indo-Pacific nudibranchs and sea slugs: a field guide to the world’s most diverse fauna. Sea Challengers, Gig HarborGoogle Scholar
  33. Gosliner TM, Valdés Á, Behrens DW (2015) Nudibranch & sea slug identification: Indo-Pacific. New World Publications, JacksonvilleGoogle Scholar
  34. Hillis DM, Bull JJ (1993) An empirical test of bootstrapping as a method for assessing confidence in phylogenetic analysis. Syst Biol 42:182–192CrossRefGoogle Scholar
  35. Hoegh-Guldberg O, Mumby PJ, Hooten AJ, Steneck RS, Greenfield P, Gomez E, Harvell CD, Sale PF, Edwards AJ, Caldeira K, Knowlton N (2007) Coral reefs under rapid climate change and ocean acidification. Science 318:1737–1742CrossRefGoogle Scholar
  36. Huelsenbeck JP, Rannala B (2004) Frequentist properties of Bayesian posterior probabilities of phylogenetic trees under simple and complex substitution models. Syst Biol 53:904–913CrossRefGoogle Scholar
  37. Hughes TP, Baird AH, Bellwood DR, Card M, Connolly SR, Folke C, Grosberg R, Hoegh-Guldberg O, Jackson JBC, Kleypas J, Lough JM (2003) Climate change, human impacts, and the resilience of coral reefs. Science 301:929–933CrossRefGoogle Scholar
  38. Jensen KR (1992) Anatomy of some Indo-Pacific Elysiidae (Opisthobranchia: Sacoglossa (= Ascoglossa)), with a discussion of the generic division and phylogeny. J Moll Stud 58:257–296CrossRefGoogle Scholar
  39. Jensen KR (2007) Biogeography of the Sacoglossa (Mollusca, Opisthobranchia). Bonn Zool Beitr 55:255–281Google Scholar
  40. Kearse M, Moir R, Wilson A, Stones-Havas S, Cheung M, Sturrock S, Buxton S, Cooper A, Markowitz S, Duran C, Thierer T (2012) Geneious Basic: an integrated and extendable desktop software platform for the organization and analysis of sequence data. Bioinformatics 28:1647–1649CrossRefGoogle Scholar
  41. Knowlton N, Weight LA, Solórzano LA, Mills DK, Bermingham E (1993) Divergence in proteins, mitochondrial DNA, and reproductive compatibility across the Isthmus of Panama. Science 260:1629–1632CrossRefGoogle Scholar
  42. Koh DB (2006) Sea slugs of Korea. Pungdeung Publishing, SeoulGoogle Scholar
  43. Krug PJ (2011) Patterns of speciation in marine gastropods: a review of the phylogenetic evidence for localized radiations in the sea. Am Malacol Bull 29:169–186CrossRefGoogle Scholar
  44. Krug PJ, Ellingson RA, Burton R, Valdés Á (2007) A new poecilogonous species of sea slug (Opisthobranchia: Sacoglossa) from California: comparison with the planktotrophic congener Alderia modesta (Lovén, 1844). J Moll Stud 73:29–38CrossRefGoogle Scholar
  45. Krug PJ, Vendetti JE, Ellingson RA, Trowbridge CD, Hirano YM, Trathen DY, Rodriguez AK, Swennen C, Wilson NG, Valdés Á (2015) Species selection favors dispersive life histories in sea slugs, but higher per-offspring investment drives shifts to short-lived larvae. Syst Biol 64:983–999CrossRefGoogle Scholar
  46. Krug PJ, Vendetti JE, Valdés A (2016) Molecular and morphological systematics of Elysia Risso, 1818 (Heterobranchia: Sacoglossa) from the Caribbean region. Zootaxa 4148:1–137CrossRefGoogle Scholar
  47. Kumar S, Stecher G, Tamura K (2016) MEGA7: Molecular Evolutionary Genetics Analysis Version 7.0 for bigger datasets. Mol Biol Evol 33:1870–1874CrossRefGoogle Scholar
  48. Marko PB (2002) Fossil calibration of molecular clocks and the divergence times of geminate species pairs separated by the Isthmus of Panama. Mol Biol Evol 19:2005–2021CrossRefGoogle Scholar
  49. Mayr E (1954) Geographic speciation in tropical echinoids. Evolution 8:1–18CrossRefGoogle Scholar
  50. Mumby PJ, Hastings A, Edwards HJ (2007) Thresholds and the resilience of Caribbean coral reefs. Nature 450:98–101CrossRefGoogle Scholar
  51. Nakano R (2004) Opisthobranchs of Japan Islands. Rutles, TokyoGoogle Scholar
  52. Ono A (1999) Opisthobranchs of Kerama Islands. TBS-Britannica, TokyoGoogle Scholar
  53. Ornelas-Gatdula E, Camacho-García Y, Schrödl M, Padula V, Hooker Y, Gosliner TM, Valdés Á (2012) Molecular systematics of the ‘Navanax aenigmaticus’ species complex (Mollusca, Cephalaspidea): coming full circle. Zool Scr 41:374–385CrossRefGoogle Scholar
  54. Ortea J, Moro L, Bacallado JJ, Espinosa J (1998) Catálogo abreviado de las especies del orden Sacoglossa (= Ascoglossa, Mollusca: Opisthobranchia) de las Islas Canarias y de Cabo Verde. Rev Acad Canar Cien 10:85–96Google Scholar
  55. Pagel M, Meade A (2004) A phylogenetic mixture model for detecting pattern-heterogeneity in gene sequence or character-state data. Syst Biol 53:571–581CrossRefGoogle Scholar
  56. Palumbi SR (1996) Nucleic acids II: The polymerase chain reaction. In: Hillis DM, Moritz C, Mable BK (eds) Molecular systematics, 2nd edn. Sinauer, Sunderland, Massachusetts, pp. 205–247Google Scholar
  57. Pruvot-Fol A (1951) Études des nudibranches de la Méditerranée 2. Archiv Zool Exp Gén 88:1–80, pls. 1–4Google Scholar
  58. Pruvot-Fol A (1954) Mollusques opisthobranches. Faune Fr 58:1–460Google Scholar
  59. Puillandre N, Lambert A, Brouillet S, Achaz G (2012) ABGD, Automatic Barcode Gap Discovery for primary species delimitation. Mol Ecol 21:1864–1877CrossRefGoogle Scholar
  60. Rambaut A, Suchard MA, Xie D, Drummond AJ (2013) Tracer v1.6. Accessed 16 January 2016
  61. Rudman WB (2001) Placida cremoniana from New South Wales. Sea Slug Forum. Accessed 28 April 2017
  62. Sammut C, Perrone AS (1998) A preliminary check-list of Opisthobranchia (Mollusca, Gastropoda) from the Maltese islands. Basteria 62:221–240Google Scholar
  63. Schmekel L (1968) Ascoglossa, Notaspidea und Nudibranchia im litoral des Golfes von Neapel. Rev Suisse Zool 75:103–155Google Scholar
  64. Schmekel L, Portmann A (1982) Opisthobranchia des Mittelmeeres: Nudibranchia und Saccoglossa. Monografia della Stazione Zoologica di Napoli 40. Springer-Verlag, BerlinCrossRefGoogle Scholar
  65. Schulz S (2005) Placida cremoniana from Wollongong, NSW, Australia. Sea Slug Forum. Accessed 28 April 2017
  66. Silvestro D, Michalak I (2012) raxmlGUI: a graphical front-end for RAxML. Org Divers Evol 12:335–337CrossRefGoogle Scholar
  67. Trinchese S (1892) Nuovi ascoglossi del Golfo di Napoli. Rend Accad Sci Fis Mat Soc Napoli 2:154Google Scholar
  68. Trinchese S (1896) Ricerche anatomiche sulla Hermaea cremoniana (Tr.). Mem R Accad Sci Ist Bologna Ser 5 6:35–45Google Scholar
  69. Trowbridge CD, Hirano YM, Hirano YJ, Sudo K, Shimadu Y, Watanabe T, Yorifuji M, Maeda T, Anetai Y, Kumagai K (2010) Subtropical sacoglossans in Okinawa—at “special risk” or “predictably rare”? Am Malacol Bull 28:167–181CrossRefGoogle Scholar
  70. Valdés Á (2004) Phylogeography and phyloecology of dorid nudibranchs (Mollusca, Gastropoda). Biol J Linn Soc 83:551–559CrossRefGoogle Scholar
  71. Warren L (2000) Stiliger cremoniana from SE Sulawesi. Sea Slug Forum. Accessed 28 April 2017
  72. Yonow N (2015) Sea slugs: unexpected biodiversity and distribution. In: Rasul NMA, Stewart ICF (eds) The Red Sea. Springer, Berlin, pp 531–550Google Scholar

Copyright information

© Senckenberg Gesellschaft für Naturforschung and Springer-Verlag GmbH Germany 2017

Authors and Affiliations

  1. 1.Department of Biological SciencesCalifornia State Polytechnic UniversityPomonaUSA
  2. 2.Department of Biological SciencesCalifornia State University Los AngelesLos AngelesUSA

Personalised recommendations