Abstract
The anatomy of Cossura pygodactylata Jones, 1956 (Annelida; Cossuridae) is presented, based on the study of specimens collected during the BIOICE project in Icelandic waters and additional material from the White Sea. General gross external and internal anatomy were investigated by means of micro-computed tomography (micro-CT) and compared with results obtained with light microscopy histological sectioning (LMHS). Micro-CT revealed a highly regionalised gut, posterior to the pharyngeal cavity and oesophagus, divided in an anterior stomach and a posterior intestine with different morphologies. The stomach is in the thoracic region, dorsally positioned and divided in a short and narrow anterior part and a longer posterior one, with an increasing diameter towards its posterior end. Both stomach regions bear a dorsal infolding of tissue, along its inner wall, that resembles to the typhlosole of the Clitellata. The heart is dorsally located and contains a heart body above the hind stomach. The intestine is wider than the stomach, without dorsal infolding inside the lumen and filling most part of the internal body cavity. A transitional cup-shaped gut element connecting the stomach and the intestine could be observed at the level of the last thoracic segment. In general, the resolution of micro-CT images reflects reasonably well the main elements of gross external and internal anatomy of cossurids, and that of gut architecture in particular.
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References
Alba-Tercedor J, Sánchez-Tocino L (2011) The use of the SkyScan 1172 high-resolution micro-CT to elucidate if the spicules of the sea slugs (Mollusca: Nudibranchia, Opisthobranchia) have a structural or a defensive function. SkyScan Users Meeting 2011:113–121
Day JH (1963) The Polychaete fauna of South Africa. Part 8: new species and records from grab samples and dredgings. Bull Br Mus Nat Hist, Ser Zool 10(7):383–445
Dinley J, Hawkins L, Paterson G, Ball AD, Sinclair I, Sinnett-Jones P, Lanham S (2010) Micro-computed X-ray tomography: a new non-destructive method of assessing sectional, fly-through and 3D imaging of a soft-bodied marine worm. J Microsc 238:123–133
Faulwetter S, Dailianis T, Vasileiadou A, Arvanitidis C (2013a) Contrast enhancing techniques for the application of micro-CT in marine biodiversity studies. Microsc Anal 27:4–7
Faulwetter S, Vasileiadou A, Kouratoras M, Dailianis T, Arvanitidis C (2013b) Micro-computed tomography: introducing new dimensions to taxonomy. ZooKeys 263:1–45
Fournier JA, Petersen ME (1991) Cossura longocirrata: redescription and distribution, with notes on reproductive biology and a comparison of described species of Cossura (Polychaeta: Cossuridae). Ophelia Suppl 5:63–80
Grube AE (1878) Annulata Semperiana. Beiträge zur Kenntniss der Annelidenfauna der Philippinen. Mem Acad Imp Sci St Petersb, Ser 7 25(8):1–300
Jones ML (1956) Cossura pygodactylata, a new annelid from San Francisco Bay (Polychaeta: Cirratulidae). J Wash Acad Sci 46:127–130
Marchán DF, Novo M, Fernández R, De Sosa I, Trigo D, Cosín DJD (2016) Evaluating evolutionary pressures and phylogenetic signal in earthworms: a case study–the number of typhlosole lamellae in Hormogastridae (Annelida, Oligochaeta). Zool J Linnean Soc 178(1):4–14
Michel C (1988) Intestine and digestive glands. In: Westheide W, Hermans CO (eds) The ultrastructure of Polychaeta. Microfauna Mar 4:157–176
Parapar J (2003) Oweniidae (Annelida, Polychaeta) from Icelandic waters, collected by the BIOICE project, with a description of Myrioglobula islandica n. sp. Sarsia 88:274–290
Parapar J, Candás M, Cunha-Veira X, Moreira J (2017a) Exploring annelid anatomy using micro-computed tomography: a taxonomic approach. Zool Anz 270:19–42
Parapar J, Kongsrud JA, Kongshavn K, Alvestad T, Aneiros F, Moreira J (2017b) A new species of Ampharete (Annelida: Ampharetidae) from the NW Iberian Peninsula, with a synoptic table comparing NE Atlantic species of the genus. Zool J Linn Soc. https://doi.org/10.1093/zoolinnean/zlx077
Parapar J, Moreira J, Helgason GV (2011) Distribution and diversity of the Opheliidae (Annelida, Polychaeta) on the continental shelf and slope of Iceland, with a review of the genus Ophelina in northeast Atlantic waters and description of two new species. Org Div Evol 11:83–105
Parapar J, Moreira J, Helgason GV (2013) First record of genus Orbiniella Day, 1954 (Polychaeta: Orbiniidae) in North Atlantic Ocean with the description of a new species. Zootaxa 4006:330–346
Parapar J, Moreira J, Gil J, Martín D (2016) A new species of the genus Terebellides (Polychaeta, Trichobranchidae) from the Iranian coast. Zootaxa 4117:321–340
Paterson GLJ, Sykes D, Faulwetter S, Merk R, Ahmed F, Hawkins LE, Dinley J, Ball AD, Arvanitidis C (2014) The pros and cons of using micro-computed tomography in gross and microanatomical assessments of polychaetous annelids. Mem Mus Vic 71:237–246
Rouse GW (2001) Cossuridae day, 1963. In: Rouse GW, Pleijel F (eds) Polychaetes. Oxford University Press, Oxford, pp 46–48
Rouse GW, Tzetlin AB (1997) Ultrastructure of the body wall and gametogenesis in Cossura cf. longocirrata (Cossuridae Polychaeta). Invert Reprod Develop 32:41–54
Saulnier-Michel C (1992) Chapter 2.3. Polychaeta: digestive system. In: Harrison FH, Gardiner SK (eds) Microscopic anatomy of invertebrates, vol. 7 Annelida, Wiley-Liss, New York, pp 53−69
Sykes D, Hawkins L, Ahmedl F, Faulwetter S, Arvanitidis C, Paterson G (2013) 3D virtual histology of Polychaetes using micro-CT. Microsc Microanal 19:644–645
Tampi PRS (1958) Anatomy of Armandia leptocirris Grube (Polychaeta). J Zool Soc India 10:15–32
Thulin G (1921) Biologisch-faunistiche Unterschungen aus dem Vresund. IV. Über Cossura longocirrata Webster & Benedict und über die Röhren von Disoma multisetosum Örsted. Lunds Univ Ersskr NF, Avd 2 17(10):2–15
Tzetlin AB (1994) Fine morphology of the feeding apparatus of Cossura sp. (Polychaeta, Cossuridae) from the White Sea. Mém Mus Natl Hist Nat 162:137–143
Webster HE, Benedict JE (1887) The Annelida Chaetopoda from Eastport, Maine. U.S. Commision of Fish and Fisheries. Rep US Fish Comm 1885:707–755
Zhadan A (2015) Cossuridae (Annelida: Polychaeta: Sedentaria) from Australian and adjacent waters: the first faunistic survey. Rec Aust Mus 67:1–24
Zhadan AE, Vortsepneva EV, Tzetlin AB (2012) Redescription and biology of Cossura pygodactylata Jones, 1956 (Polychaeta: Cossuridae) in the White Sea. Invertebr Zool 9:115–125
Zhadan A, Vortsepneva E, Tzetlin A (2014) Three-dimensional reconstruction of the musculature of Cossura pygodactylata Jones, 1956 (Annelida: Cossuridae). Zool Anz 253:181–191
Zhadan A, Vortsepneva E, Tzetlin A (2015) Ontogenetic development and functioning of the anterior end of Cossura pygodactylata Jones, 1956 (Annelida: Cossuridae). Zoomorphology 134:509–521
Acknowledgements
The authors would like to thank Gudmundur Gudmundsson, Director of Collections and Systematics Department (Icelandic Institute of Natural History, Reykjavik), Gudmundur Vidir Helgason (Institute of Biology, University of Iceland, Reykjavik) and the Director of the Sandgerdi Marine Centre until 2013 for their help and advice during JP visits to the SMC, and to Solrun Bragadóttir and the rest of the women of the SMC involved in sorting the specimens from the BIOICE samples. The authors are also grateful to María Candás and Xela Cunha-Veira (EBMG, USC) for their help with the micro-CT images. The authors would also like to thank Nathalie Yonow (Swansea, Wales, UK) for linguistic correction of the manuscript, two anonymous reviewers for their helpful comments that greatly contributed to improve the organisation and clarity of the information provided and Karin Meiβner, Guest Editor of Marine Biodiversity, for her support during the review process and generous effort to improve the presentation of the text.
Funding
This work was partially supported by several grants from the European Union’s Training and Mobility of Researchers program and the Universidade da Coruña to the first author to visit the Sandgerdi Marine Centre. The micro-CT study was financially supported by the project Fauna Ibérica XI - Polychaeta VI (CGL2014-53332-C5-3-P). The work of AZ, AT and EV was supported by grants 15-29-02447 and 16-04-00343 from the Russian Foundation for Basic Research. The histological investigations were supported by the Russian Scientific Foundation, grant 14-50-00029.
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This article is part of the Topical Collection on Biodiversity of Icelandic Waters by Karin Meißner, Saskia Brix, Ken M. Halanych, and Anna Jazdzewska.
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Parapar, J., Zhadan, A., Tzetlin, A. et al. Exploring the anatomy of Cossura pygodactylata Jones, 1956 (Annelida, Cossuridae) using micro-computed tomography, with special emphasis on gut architecture. Mar Biodiv 48, 751–761 (2018). https://doi.org/10.1007/s12526-018-0873-x
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DOI: https://doi.org/10.1007/s12526-018-0873-x