Abstract
During surveys of the Gastrotricha of the Tropical Northwestern Atlantic (TNWA, Caribbean Sea), we came across numerous specimens of the uncommon macrodasyidan, Xenodasys riedli (Xenodasyidae). Abundance data on gastrotrichs is rare and entirely absent for this species; moreover, there are no data on morphological variation of X. riedli outside its type locality (North Carolina, USA). Here, we provide new abundance data on specimens collected from St. John Island (US Virgin Islands), as well as new metric and morphological data from specimens collected on San Salvador Island (Bahamas), Tobago, and a sublittoral environment on the Atlantic Coast of Florida (USA). In the interstitial environments of St. John, X. riedli was most abundant at 0.8 m depth in moderately well-sorted sediments. It reached maximum abundance of 89.5 ± 42.7 ind./102 cm and made up 69.7% of the total taxocoenosis. Metric variation revealed that specimens at all sites in the TNWA and Florida had smaller body sizes than those recorded at the type locality, but showed only limited variation in the size and number of taxonomic characters. Observations of specimen from Florida using scanning electron microscopy (SEM) revealed details that were overlooked in the type description. For example, we observed 8 dorsal head plates (11 in the original description), 1 pair of anterior medial plates, and 3 ventral plates, the latter of which were not described in the type specimens. We confirm the existence of round scales on the dorsolateral margins, and note that spineless-scales are also present in between the spined scales on the lateral body wall. We also determined that the lateral spined scales possess dorsal and ventral spines instead of anterior and posterior spines, which was their original assumed position. This research reveals that SEM remains the best diagnostic tool for characterizing gastrotrich morphology, and should be part of all future studies of gastrotrich taxonomy.
Similar content being viewed by others
References
Araújo TQ, Hochberg R (2016) First description of a gastrotrich with four scale types, including feathered biancres, a novel find for Gastrotricha. J Mar Biol Assoc U K. doi:10.1017/S0025315416000333
Clausen C (2004) Gastrotricha from the Faroe Bank. Sarsia 89:137–141
D’Hondt JL (1970) Inventaire de la faune marine de Roscoff: Gastrotriches, kinorhynques, rotifers, tardigrades. Editions de la Station Biologique de Roscoff, Roscoff
Gray JS (1971) The effects of pollution on sand meiofauna communities. In: Zavodnik D (ed) Proceedings of the Sixth European Symposium on Marine Biology, Rovinj, Croatia, Yugoslavia September 27-October 2, 1971. Thalassia Jugoslavica 7: 79-86
Hochberg R (2007) Comparative immunohistochemistry of the cerebral ganglion in Gastrotricha: an analysis of FMRFamide-like immunoreactivity in Neodasys cirritus (Chaetonotida), Xenodasys riedli and Turbanella cf. hyalina (Macrodasyida). Zoomorphology 126:245–264
Hummon WD (1974) Some taxonomic revisions and nomenclatural notes concerning marine and brackish-water Gastrotricha. Trans Am Microsc Soc 92:194–205
Hummon WD (1982) Gastrotricha. In: Parker SP (ed) Synopsis and classification of living organisms, vol 1. McGraw-Hill, New York, pp 857–863
Hummon WD (2010) Global_distribution_of_marine_Gastrotricha http://www.gastrotricha.unimore.it/Global_distribution_of_marine_Gastrotricha.pdf (accessed on 1st June 2015)
Hummon WD, Todaro MA, Kånneby T, Hochberg R (2010) Marine Gastrotricha of the Caribbean Sea. Proceedings of the 14th International Meiofauna Conference. 12-16 July 2010, Gent, Belgium
Kieneke A, Narkus S, Hochberg R, Schmidt-Rhaesa A (2013) Diplodasys rothei (Gastrotricha, Macrodasyida), a new marine gastrotrich species from the Bahamas. Meiofauna Marina 20:49–61
Kieneke A, Schmidt-Rhaesa A (2015) Gastrotricha. In: Schmidt-Rhaesa A (ed) Handbook of Zoology, Vol. 3: Gastrotricha and Gnathifera. De Gruyter, Berlin, pp 1-134
Kiesielewski J (1987) New records of marine Gastrotricha from the French coasts of Manche and Atlantic. I. Macrodasyida, with descriptions of seven new species. Bull Mus Natl Hist Nat, 4e serie 9:837–877
Rieger RM, Ruppert EE, Rieger GE, Schöpfer-Sterrer C (1974) On the fine structure of gastrotrichs with description of Chordodasys antennatus sp.n. Zool Scr 3:219–237
Schöpfer-Sterrer C (1969) Chordodasys riedli gen. nov., spec. nov. a macrodasyid gastrotrich with a chordoid organ. Cah Biol Mar 10:391–404
Short G, Tamm SL (1991) On the nature of paddle cilia and discocilia. Biol Bull 180:466–474
Swedmark B (1967) Trois nouveaux Gastrotriches Macrodasyoides de la faune interstitielle marine des sables de Roscoff. Cah Biol Mar 8:323–330
Todaro MA (1998) Meiofauna from the Meloria Shoals: Gastrotricha, biodiversity and seasonal dynamics. Biol Mar Mediterr 5:587–590
Todaro MA (2002) An interesting new gastrotrich from littoral meiobenthos (Long Beach Island, USA), with a key to species of Tetranchyroderma (Gastrotricha: Macrodasyida). J Mar Biol Assoc U K 82:555–563
Todaro MA, Hummon WD (2008) An overview and a dichotomous key to genera of the phylum Gastrotricha. Meiofauna Marina 16:3–20
Todaro MA, Guidi L, Leasi F, Tongiorgi P (2006a) Morphology of Xenodasys (Gastrotricha): the first species from the Mediterranean Sea and the establishment of Chordodasiopsis gen. nov and Xenodasyidae fam. nov. J Mar Biol Assoc U K 86:1005–1015
Todaro MA, Leasi F, Bizzarri N, Tongiorgi P (2006b) Meiofauna densities and gastrotrich community composition in a Mediterranean sea cave. Mar Biol 149:1079–1091
Todaro MA, Dal Zotto M, Jondelius U, Hochberg R, Hummon WD, Kånneby T, Rocha CE (2012) Gastrotricha: A Marine Sister for a Freshwater Puzzle. PLoS ONE 7:e31740
Todaro MA, Leasi F, Hochberg R (2014) A new species, genus and family of marine Gastrotricha from Jamaica, with a phylogenetic analysis of Macrodasyida based on molecular data. Syst Biodivers 12:473–488
Todaro MA, Dal Zotto M, Leasi F (2015) An integrated morphological and molecular approach to the description and systematisation of a novel genus and species of Macrodasyida (Gastrotricha). PLoS ONE 10(7), e0130278. doi:10.1371/journal.pone.0130278
Acknowledgements
Funding for this research was provided by the National Science Foundation to Rick Hochberg (DEB 0918499). Any opinions, findings, and conclusions or recommendations expressed in this article derive from the author(s) and do not necessarily reflect the views of the National Science Foundation. Many thanks to W.D. Hummon and T. Kånneby for the help provided during the expedition to St. John Island. Two anonymous reviewers are thanked for a number of constructive remarks on this manuscript.
Author information
Authors and Affiliations
Corresponding author
Additional information
Communicated by P. Martinez Arbizu
Rights and permissions
About this article
Cite this article
Schuster, J., Atherton, S., Todaro, M.A. et al. Redescription of Xenodasys riedli (Gastrotricha: Macrodasyida) based on SEM analysis, with first report of population density data. Mar Biodiv 48, 259–271 (2018). https://doi.org/10.1007/s12526-017-0667-6
Received:
Revised:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s12526-017-0667-6