Phoronida of the Gulf of Mexico

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2 Santagata, S Phoronida of the Gulf of Mexico, Pp in Felder, D.L. and D.K. Camp (eds.), Gulf of Mexico Origins, Waters, and Biota. Biodiversity. Texas A&M University Press, College Station, Texas. 65 Phoronida of the Gulf of Mexico Scott Santagata The Phoronida comprises 2 genera and at least 10 recognized species (Emig 1982), the majority of which exhibit a distinctive larval form known as the actinotroch (Zimmer 1991). Phoronids often occur in conspecific aggregations, and most species exhibit cosmopolitan distributions (Emig 1982, Zimmer 1991). Traditionally phoronids, brachiopods, and bryozoans have been designated as separate phyla within the Lophophorata and are believed to share morphological characteristics with basal deuterostome phyla (Brusca and Brusca 2003). However, molecular phylogenetic evidence has consistently identified the phoronids and brachiopods as a monophyletic group within the lophotrochozoan protostomes (Halanych et al. 1995, Cohen 2000, Helfenbein and Boore 2004), and although the bryozoans are also considered lophotrochozoans, their position relative to the phoronids and brachiopods has not been resolved (Halanych 2004, Passamaneck and Halanych 2004). One proposed resolution of the molecular phylogenetic evidence and Linnaean classification of phoronids and brachiopods was to include the phoronids as a subphylum within the phylum Brachiopoda (Cohen 2000). This interpretation has yet to be widely accepted into recent revisions of brachiopod systematics, and for the purposes of this chapter the phoronids will be treated as a phylum separate from the Brachiopoda. Phoronid systematics has been based largely on the arrangement of longitudinal muscles in the body wall, lophophore morphology, and the nephridial morphology of adults (Emig 1974, 1979, and 1982). However, reproductive traits and characteristics of competent larvae are Phoronida. After Hyman 1955, modified by F. Moretzsohn. also informative taxonomic characters (Santagata and Zimmer 2002). More importantly, a review of larval and adult characters within the Phoronida clearly shows that its species diversity is currently underestimated (Santagata and Zimmer 2002). Two controversial species that occur within the Gulf of Mexico are Phoronis architecta (Andrews, 1890) and P. psammophila (Cori, 1889). Emig (1977) proposed that P. architecta (type locality: Beaufort, North Carolina, U.S.A.) should be considered a junior synonym under P. psammophila (type locality: Messina, Italy) based on the similarity between the longitudinal muscle arrangement and nephridia morphology of adult specimens. However, P. psammophila has been described as a dioecious brooder with specialized nidamental glands and Phoronis architecta as a dioecious free- spawner that lacks nidamental glands (Brooks and Cowles 1905, Stan- 1133

3 1134 ~ Phoronida cyk, Maturo Jr., and Heard Jr. 1976, Emig 1979). Also the competent larvae of these species have different anatomical traits (Brooks and Cowles 1905, Herrmann 1979, Santagata and Zimmer 2002). Emig has asserted that the reproductive traits described for P. architecta in Brooks and Cowles (1905) actually belong to a co- occurring species, P. muelleri (Selys- Longchamps, 1903) Unfortunately, there have been no investigations of the reproductive characteristics of phoronids within the Gulf of Mexico. Previous surveys have largely assumed that their specimens were solely Phoronis architecta (see Hedgpeth 1954, Paine 1961, Hildebrande and King 1973, 1975, Holland 1975, Flint, Kalke, and Rabalais 1981). Although a few actinotroch types have been collected from the plankton, they were not identified (Hedgpeth 1954, Hildebrand and King 1973, 1975). Some of the more widely observed adult specimens were provided to me by the Gulf Specimen Marine Laboratory and were collected near Panacea, Florida. These specimens have longitudinal muscle patterns, reproductive traits, and larval characteristics consistent with those originally described for P. architecta from Beaufort, North Carolina (Andrews 1890, Brooks and Cowles 1905, Santagata pers. obs.). Moreover, the longitudinal muscle patterns for phoronids from Panacea, Florida, differentiate these specimens from P. muelleri, and their reproductive traits separate them from P. psammophila. Overall, there are several problems concerning the species identification and diversity of phoronids in the Gulf of Mexico; however, until a comprehensive review of all North American phoronid species is completed, the best designation for the phoronid specimens from Panacea, Florida, remains P. architecta. Further sampling will be required to determine whether P. psammophila or another undescribed species similar to it also occurs within the Gulf of Mexico. At least 2 other phoronid species are reported from the Gulf of Mexico, Phoronis muelleri (Selys- Longchamps, 1903) and P. hippocrepia (Wright, 1856). Both species have circumglobal distributions and exhibit anatomical, reproductive, and larval characteristics that easily differentiate these species from P. architecta or P. psammophila (see Silén 1954, Emig 1982). Phoronis hippocrepia often occurs on hard substrates in tightly packed conspecific aggregations, and P. muelleri has been found at greater depths (Emig 1979, Emig 1982). Similar to other species of phoronids, P. muelleri and P. hippocrepia are found in the lower intertidal (itd) to moderately deep habitats worldwide. One other phoronid species that may occur in the Gulf of Mexico but has not been recorded is Phoronis ovalis (Wright, 1856). This species is smaller than other phoronid species, produces a slug- like larva, and has been found in burrows in the shells of the common jingle shell, Anomia simplex (d Orbigny, 1842), from the Atlantic coast of the southeastern United States (Stancyk, Maturo Jr., and Heard Jr. 1976) and also Stramonita (=Thais) haemostoma floridana (Conrad, 1837) from Brazil (Marcus 1949, Forneris 1959). Abbreviations Abbreviations used in the checklist are: csp = cosmopolitan; hsb = hard substrate; itd = lower intertidal; ne = northeast; nw = northwest; plk = planktonic; sft = soft substrate; sw = southwest. Acknowledgments This work was completed during a postdoctoral fellowship at the Smithsonian Marine Station (Fort Pierce, Florida). I thank the staff of the Smithsonian Marine Station, Friday Harbor Laboratories, Mary Rice, Valerie Paul, Darryl Felder (University of Louisiana at Lafayette), John Wes Tunnell (TAMU), Richard Greene (Smithsonian Libraries), Kris Metzger (HBOI library), Ed Ruppert (Clemson University), Dennis Allen (BMFL), Dan Rittschof (Duke Marine Laboratory), Richard Strathmann (FHL), and Russel L. Zimmer (USC). This publication is contribution 714 for the Smithsonian Marine Station at Fort Pierce. References 1. Andrews, E. A On a new American species of the remarkable animal Phoronis. Annales and Magazine of Natural History 5: Brooks, W. K., and R. P. Cowles Phoronis architecta: its life history, anatomy and breeding habits. Memoirs of the National Academy of Sciences 10: Brusca, R. C., and G. J. Brusca, Invertebrates. 2nd ed. Sinauer, Sunderland, Massachusetts. 936 pp. 4. Cohen, B. L Monophyly of brachiopods and phoronids: reconciliation of molecular evidence with Linnaean classification (the subphylum Phoroniformea nov.). Proceedings of the Royal Society of London. Series B 267: Cori, C. J Beitrag zur Anatomie der Phoronis [inaugural- dissertation]. University of Leipzig. Prague, Germany. 48 pp.

4 Santagata ~ Emig, C. C The systematics and evolution of the phylum Phoronida. Zeitschrift für Zoologische Systematik und Evolutionsforschung 12: Emig, C. C Notes sur la localisation, l écologie et la taxonomie des phoronidiens. Téthys 7: Emig, C. C., British and Other Phoronids. Synopses of the British Fauna No. 13, D. M. Kermack and R. S. K. Barnes, eds. Academic Press, New York. 57 pp. 9. Emig, C. C The biology of Phoronida. Advances in Marine Biology 19: Flint, R. W., R. D. Kalke, and S. C. Rabalais Quantification of Extensive Freshwater Input to Estuarine Benthos. Report to the Texas Department of Water Resources, Contract No. IAC (80 81). University of Texas Marine Science Institute, Port Aransas. 11. Forneris, L Phoronidea from Brazil. Boletim do Instituto Océanographico, San Paulo 10: Halanych, K. M The new view of animal phylogeny. Annual Review of Ecology, Evolution and Systematics 35: Halanych, K. M., J. D. Bacheller, A. M. A. Aguinaldo, S. M. Liva, D. M. Hillis, and J. A. Lake Evidence from 18S ribosomal DNA that the lophophorates are protostome animals. Science 267: Hedgpeth, J. W Phoronida. Page 367 in P. S. Galtsoff, ed. Gulf of Mexico, Its Origin, Waters, and Marine Life. Fishery Bulletin 89. Fishery Bulletin of the Fish and Wildlife Service, Volume 55, Washington, D.C. 15. Helfenbein, K. G., and J. L. Boore The mitochondrial genome of Phoronis architecta: comparisons demonstrate that phoronids are lophotrochozoan protostomes. Molecular Biology and Evolution 21: Herrmann, K Larval development and metamorphosis of Phoronis psammophila (Phoronida, Tentaculata). Helgoländer Wissenschaftliche Meeresuntersuchungen 32: Hildebrand, H. H., and D. King A Preliminary Biological Study of the Cayo del Oso and the Pita Island Area of the Laguna Madre Corpus Christi Power and Light Company, Corpus Christi, Texas. 18. Hildebrand, H. H., and D. King A Biological Study of the Cayo del Oso and the Pita Island Area of the Laguna Madre Corpus Christi Power and Light Company, Corpus Christi, Texas. 19. Holland, J. S., N. J. Maciolek, R. D. Kalke, and C. H. Oppenheimer A Benthos and Plankton Study of the Corpus Christi, Copano, and Aransas Bay Systems. III. Final report to the Texas Water Development Board. University of Texas Marine Science Institute, Port Aransas. 20. Marcus, E. du B- R Phoronis ovalis from Brazil. Boletim da Faculdade de Filosofia Ciências e Letras da Universidade de São Paulo, Série Zoologia 14: Paine, R. T Observations on Phoronis architecta in Florida waters. Bulletin of Marine Science 11: Passamaneck, Y. J., and K. M. Halanych Evidence from Hox genes that bryozoans are lophotrochozoans. Evolution and Development 6: Santagata, S., and R. L. Zimmer Comparison of the neuromuscular systems among actinotroch larvae: systematic and evolutionary implications. Evolution and Development 4: Selys- Longchamps, M. de Ueber Phoronis und Actinotrocha bei Helgoland. Helgoländer Wissenschaftliche Meeresuntersuchungen 6: Silén, L Developmental biology of the Phoronidea of the Gullmar Fiord Area (west coast of Sweden). Acta Zoologica (Stockholm) 35: Stancyk, S. E., F. J. S. Maturo Jr., and R. W. Heard Jr Phoronids from the East Coast of the United States. Bulletin of Marine Science 26: Wright, T. S Description of two tubicolar animals. Edinbury New Philosophical Journal 4: Zimmer, R. L Phoronida. Pp in A. C. Giese, J. S. Pearse, and V. B. Pearse, eds. Reproduction of Marine Invertebrates, vol. 6, Echinoderms and Lophophorates. The Boxwood Press, Pacific Grove, California. Submitted: March 2005 Accepted: April 2005

5 1136 ~ Phoronida Taxonomic summary for the Phoronida of the Gulf of Mexico. Component subgroups Total species Number of endemic species Number of nonindigenous species Phoronis Checklist of Phoronida from the Gulf of Mexico. Taxon Habitat- Biology Depth (m) Overall geographic range GMx range References / Endnotes Phylum: Phoronida Phoronis architecta (Andrews, 1890) sft itd 10 csp? ne, nw 10 1, 14, 19, 21 2, 26 3 Phoronis muelleri (Selys- Longchamps, 1903) sft itd 10 csp nw 9 4, 5 Phoronis hippocrepia (Wright, 1856) hsb itd 10 csp sw 9 6, 7 Unidentified actinotroch larvae plk unknown nw 14 8, 17 9, 18 1 Nueces- Corpus Christi Bay, Texas. 2 Panacea, Florida. 3 Tampa Bay and Seahorse Key, Florida. 4 Port Aransas, Texas. 5 Generally found at depths greater than 10 m but has also been found at depths greater than 200 m worldwide. 6 Veracruz, Mexico. 7 Generally found at 0 10 m but has been found at depths of 55 m worldwide. 8 Baffin Bay Laguna Madre, Texas. 9 Aransas Copano Bay, Texas.