A Review on Taxonomy of Phylum Kinorhyncha

C. Jeeva, P. M. Mohan, P. Ragavan, V. Muruganantham

Department of Ocean Studies and Marine Biology, Pondicherry University, Brookshabad Campus, Port Blair, Andaman and Nicobar Islands, India.

DOI: 10.4236/ojms.2020.104020                

Abstract

Kinorhyncha is exclusively marine, holobenthic, free-living, meiofaunal species found in all marine habitats in the world. However, information on geographical distribution and taxonomical distributional status of Kinorhyncha are needed further understanding. This research article presents a compiled, up-to-date checklist of the Phylum Kinorhyncha based on bibliographical survey and revision of taxon names. Present checklist of this phylum comprises 271 species belonging to 30 genera and 13 families. The families are distributed under three orders, Echinorhagata Sorensen et al. 2015, Kentrorhagata Sorensen et al. 2015, Xenosomata Zelinka, 1907. Among the 271 valid species, in the last five years 82 new species emerged, two new orders and three families were described. It also includes nine new genera. This checklist could serve as a valuable tool to encourage comparison of inter and intraregional research on Kinorhyncha as well as it can be used as baseline data for future taxonomical revision.

Keywords

Checklist, Kinorhyncha, Meiofauna, Diversity, Distribution

1. Introduction

Kinorhyncha is exclusively marine, holobenthic, free-living, meiofaunal species within a size range of 0.13 - 1.04 mm body length [1]. Their distributions are global, and are found in all marine habitats, often reported to have a high tolerance towards variations in sediment size, salinity and hypoxia levels [2]. The first Kinorhyncha species was described 165 years ago by Dujardin [3]. However, the knowledge of these animals is far from complete due to the fact that very small communities of researchers are interested in this phylum (currently less than few tens of researchers are working in this field, worldwide). Studies of Zelinka [4] [5] [6] [7] [8] focusing on Kinorhynch systematics and his monograph “Monographie der Echinodera” [9] completely revised the “Systematic Systems” of Reinhard [10] [11], and described 12 species from adult stages (in addition to four species described earlier), 34 species from juvenile stages, and for the first time provided information on all aspects of the morphology and biology of this taxon [9]. 20th century studies of Higgins have been considered to be a major step forward in the taxonomic studies of Kinorhyncha. Studies of Higgins and Co-workers after 1960 described 60 new species, re-described 14 species, and established six new genera [12] - [41]. During the last decade, several new species were described by various researchers [42] - [81]. Further, the existing literature says that Sørensen [82] listed 205 species of Kinorhyncha described from adult specimens, whereas Neuhaus [1] listed 191 species of Kinorhyncha described from adult specimens, and 50 species of juvenile. However, molecular phylogenetic studies by Yamasaki et al. [83] and Sørensen et al. [84], and description of new species from various geographical location warrant that the periodical revision of the Kinorhyncha classification is essential to make the taxonomical work in a single floor, for the clear-cut discussion. An attempt has been made on this line and their results are discussed herewith.

2. Method

This review was carried out from the existing published results. The observed species are ordered alphabetically and grouped based on the taxonomic status under the following categories.

1) A Valid species (described from adult stage).

2) Nomina dubia (described only from Juvenile stage).

3) Taxon inquirendum (identity is uncertain or disputed by different experts).

A species known only from juvenile stages are generally regarded as nomina dubia, but names are available and valid according to the International Code of Zoological Nomenclature, which states that a new species may be described from any life history stage [85]. All taxon names were revised to employ currently accepted species names following WoRMS database [86].

3. Results

At present the phylum Kinorhyncha comprises of 271 species belonging to 30 genera and 13 families. The families are distributed under three orders, Echinorhagata Sørensen et al. 2015, Kentrorhagata Sørensen et al. 2015, Xenosomata Zelinka, 1907. Classification and list of species of Kinorhycha are given below.

4. Classification of Kinorhyncha

Class: Allomalorhagida Sørensen et al. 2015

Family: Dracoderidae Higgins & Shirayama, 1990

Genus: Dracoderes Higgins & Shirayama, 1990

Family: Franciscideridae Sørensen et al. 2015

Genus: Franciscideres Zotto et al. 2013

Family: Pycnophyidae Zelinka, 1896

Genus: Pycnophyes Zelinka, 1907

Genus: Leiocanthus Sánchez et al. 2016

Genus: Cristaphyes Sánchez et al. 2016

Genus: Higginsium Sánchez et al. 2016

Genus: Krakenella Sánchez et al. 2016

Genus: Setaphyes Sánchez et al. 2016

Genus: Fujuriphyes Sánchez et al. 2016

Family: Neocentrophyidae Higgins, 1983

Genus: Mixtophyes Sánchez et al. 2014

Genus: Neocentrophyes Higgins, 1969

Genus: Paracentrophyes Higgins, 1983

Class: Cyclorhagida Sørensen et al. 2015

Order: Echinorhagata Sørensen et al. 2015

Family: Echinoderidae Bütschli, 1876

Genus: Cephalorhyncha Adrianov, 1999

Genus: Echinoderes Claparède, 1863

Genus: Fissuroderes Neuhaus & Blasche, 2006

Genus: Meristoderes Herranz et al. 2012

Genus: Polacanthoderes Sørensen, 2008

Order: Kentrorhagata Sørensen et al. 2015

Family: Antygomonidae Adrianov & Malakhov, 1994

Genus: Antygomonas Nebelsick, 1990

Family: Cateriidae Gerlach, 1950

Genus: Cateria Gerlach, 1956

Family: Centroderidae Zelinka, 1896

Genus: Centroderes Zelinka, 1907

Genus: Condyloderes Higgins, 1969

Family: Semnoderidae Remane, 1929

Genus: Semnoderes Zelinka, 1907

Genus: Sphenoderes Higgins, 1969

Genus: Parasemnoderes Adrianov & Maiorova 2018

Family: Zelinkaderidae Higgins, 1990

Genus: Triodontoderes Sørensen & Rho, 2009

Genus: Zelinkaderes Higgins, 1990

Family: incertae sedis

Genus: Tubulideres Sørensen et al. 2007

Family: incertae sedis

Genus: Wollunquaderes Sørensen & Thormar, 2010

Order: Xenosomata Zelinka, 1907

Family: Campyloderidae Remane, 1929

Genus: Campyloderes Zelinka, 1907

Genus: Ryuguderes Yamasaki, 2016

Based on the literature collected, the present study reports 271 species valid species. Among these species, 82 species were added during the latter period of 2013 and was not included in the WoRMS data base (Table 1).

Table 1. List of species identified after the works of 2013 (which are not available currently in WoRMS database).

5. Discussion

Before this study, Nehaus [1] was prepared the checklist for Kinorhyncha which exhibited only 189 species. The present study included another 82 species and designated as a newly described species. Besides, Nehaus [1] classified 4 species (Echinoderes druxi, E. masudai, E. steineri and Pycnophyes echinoderoides) as valid, although they are regarded as a nomen dubium. However, these 4 species are also currently classified as taxon inquirendum by WoRMS [86] due to its taxonomical uncertainty and described in the present work. Based on the above consideration, now the Kinorhyncha has 271speceis as valid species, 51 species under the category of nomendubium and 4 species as taxon inquirendum. Table 2, exhibited the nomendubium as discussed by the Nehaus [1] for 50 species and WoRMS [86] described 55 species.

According to WoRMS [86] data base and Nehaus [1], a total of 189 Species and 191 Species were reported, respectively (Table 3). E. druxi d’Hondt, 1973.E. masudai Abe, 1930, E. steineri (Chitwood, 1951), P. calmani Southern, 1914, P. echinoderoides Zelinka, 1928, and P. oshoroensis Yamasaki et al. 2012 were named to be valid. However, according to WoRMS [86], out of these 6 species, 4 species namely E. druxi, E. masudai, E. steineri and P. echinoderoides were termed as taxon inquirendum. Whereas, the status of P. calmani is unaccepted, and P. oshoroensis Yamasaki et al. [87], is not recorded.

Based on the data presented in Table 3 and Table 4, species such as Campyloderes vanhoeffeni var. kerguelensis Zelinka, 1913, Centroderes eisigii Zelinka, 1928, E. augustae Sørensen & Landers, 2014 and E. skipperae Sørensen & Landers, 2014 are valid according to WoRMS [86], however, not added in the works of Nehaus [1]. Of these, 2 species, namely E. augustae Sørensen & Landers, 2014, and E. skipperae Sørensen & Landers 2014, were identified after 2014, i.e., after the works of Nehaus [1].

Table 2. List of invalid names given according to Nehaus (2013) and WoRMS database for nomendubium and taxon inquirendum.

Table 3. Consolidated lists of the Kinorhynch species (valid and invalid) identified across the globe.

Table 4. List of species present in India.

5.1. Echinoderes druxi and Echinoderes steineri

Higgins [26] states that common errors that occur in the taxonomic interpretation of Echinoderes are related to the lateral spines. Huys and Coomans [88] states their doubt about the spine formula for E. steineri Chitwood, 1951, and E. druxi d’Hondt, 1973. Moreover, the latter one is also proved to be a poorly described species [45].

5.2. E. masudai

E. masudai Abe, 1930 is a cyclorhagid Kinorhynch found on the Gogoshima Island near Hiroshima [89]. The description of the species was however too poor to do comparisons practically and E. masudai is considered as a “species indeterminata” [26] [90] and similarly it is currently designated as a taxon inquirendum.

5.3. Pycnophyes echinoderoides

Higgins [26] described species from juvenile stages, and mentioned it as species indeterminatum adding that it was uncertain to be matched with an adult of the same species. According to statement of Nehaus [1], E. druxi, and E. steineri, E. masudai, Pycnophyes echinoderoides are only considered as a not valid or poorly described species and indeterminate based on an inadequate description of the adult.

5.4. P. calmani

The first species assigned to this genus was P. communis Zelinka, 1908. Although this species was not described by Zelinka until 1928, these rules for “indication” were satisfied with the earlier paper. Later, Sánchez [91] stated that no available data exists for P. calmani, hence the character was coded as missing data. According to WoRMS [86] P. communis has become the accepted name for P. calmani.

5.5. C. eisigii

Echinoderes kowalewskii Reinhard [10] was considered as a nomen dubium, which was later identified as C. eisigii (Zelinka, 1928). This species differs from C. spinosus only by the lack of spines in segment 10 and by its smaller size. Unfortunately, Zelinka [9] included not only species known from adult life stages in the family Centroderidae, it has given clear information regarding C. eisigii and C. Spinosus [41]. WoRMS [86] is accepted the current status of C. eisigii.

5.6. Campyloderes vanhoeffeni var. kerguelensis

Campyloderes vanhoeffeni var. kerguelensis is considered as a variety species. As a result, Nehaus [1], might not have included this species in his paper. It is accepted as a variety species in WoRMS [86]. Three species, namely P. oshoroensis Yamasaki et al. 2012, E. augustae Sørensen & Landers, 2014, E. skipperae Sørensen & Landers, 2014 were published after the submission of list by Nehaus [1], hence this species were not added in his article. Remaining 82 species are described after 2013 and it is not updated as valid Species in WoRMS [86]. Simillary, the species Pycnophyes carinata Zelinka, 1912 (nomen nudum) is also not included in Nehaus [1].

5.7. Pycnophyes carinata

It is a poorly described species due to lack of identifying characters [8] and uncertain taxonomic significance. P. carinata is known from juvenile stage and according to Nehaus [1] it is a synonym name. As a result of this, it is considered as nomen dubium by WoRMS [86].

The present study has discussed almost 271 valid species under 30 genera. Among the 271 valid species, in the last three years 82 new species emerged along with two new Orders (Echinorhagata Sørensen et al., 2015, Kentrorhagata Sørensen et al. 2015,) and three Families (Franciscideridae Sørensen et al., 2015, incertae sedis and incertae sedis.) were described. It also includes nine new genera [(Mixtophyes Sánchez et al., 2014b; Francisderes Zotto et al., 2013; Leiocanthus Sánchez et al., 2016; Cristaphyes Sánchez et al., 2016; Higginsium Sánchez et al., 2016; Krakenella Sánchez et al., 2016; Setaphyes Sánchez et al., 2016; and Fujuriphyes Sánchez et al., 2016; Ryuguderes Yamasaki, 2016). The meiobenthic invertebrate group Kinorhyncha can be found in the oceans throughout the world, though these animals have been known for more than 150 years, only around 271 species are described till today.

6. Recent Scenario of Kinorhyncha—World Wide

Despite the fact that the distribution of Kinorhynca is widespread across the globe, research activities (more precisely taxonomy) are exclusively limited to few countries. Only few literatures are available from tropical shallow-water ecosystems. Though taxonomical studies have started long ago, it has received the attention of the researchers in the past two decades only. Here are a few of the notable taxonomical works given that are done across the globe.

Both Murakami et al. [89] and Adrianov et al. [92] have identified one species, each from Japan, which was followed by several other authors later, Yamasaki and Fujimoto [66] - (2Sp.); Yamasaki et al. [93] - (2 Sp.); Yamasaki [67] - (2Sp.), Yamasaki [73] - (1Sp.) and Sánchez and Yamasaki [94] - (2 Sp.). When compared to other countries, Korea adds to the species count with a total of 16 species in the recent years and proves to be active in the study of Kinorhyncha. Several authors have contributed to the identification of Kynorynchs like Thomsen et al. [61] - (1Sp.), Sørensen et al. [95] - (4Sp.), Sánchez et al. [60] - (4Sp.), Sørensen et al. [52] [96] - (4Sp.), Sørensen et al. [48] - (1Sp.), Sørensen et al. [47] - (1Sp.) and Altenburger et al. [68] - (1Sp.).

Spain has 8 species to its title Herranz et al. [55] - (1Sp.), Sørensen et al. [96] - (2Sp.) Sánchez et al. [53] - (2Sp.) and GaOrdóñez et al. [45] - (3Sp.). Australia, Lemburg [97] - (1Sp.), Sørensen and Thormar [51] - (1Sp.) and in Brazil, Zotto et al. [57] - (1Sp.), Sørensen and Landers [98] - (3Sp.) equally share 4 species each to his account.

Florida also has a near similar number of species identified such that of Spain, Herranz et al. [56] - (4Sp.), Sørensen et al. [43] - (2Sp.). Italy has the highest species identified across the globe, Zotto [69] - (1Sp.), Zotto and Todaro [99] - (36Sp.). Followed by Italy, the Iberian Peninsula has the highest Kinorynchs identified in the last two decades. Of this, the works of Sánchez et al. [53] - (1Sp.), Sánchez et al. [54] - (30Sp.), Sánchez et al. [62] [63] - (2Sp.) proves to be efficient with 33 identified species. Four species were identified in New Zealand by Neuhaus and Blasche [42]. Denmark has the least number of Kinorynch identified with a single species by Lundbye et al. [100].

The Panama sea exhibited 8 species [101] [102], followed by Mexico, Sørensen et al. [103] - (1Sp.); Sørensen and Landers [78] - (2Sp.) and Portugal [104] - (2Sp.).

7. Indian Scenario

Kinorhyncha is available from the intertidal zone to abyssal depths and from polar to tropical regions [1] [56] [95] [98] [105]. Still only a few dozen of literature is available from tropical shallow-water ecosystems. As far as India is concerned, works on Kinorhyncha remains scanty. The meiobenthic invertebrate group Cateria styx species has been reported from the east coast of India by Rao and Ganapati [106]. Ganapati and Rao [107] have identified species of Kinorhyncha present in Waltaire coast situated in Andhra Pradesh. Cateriagerlachi sp., were identified by Higgins [19] reported from the east coast of India. Pycnophyes sp., were collected from west coast of India by Dovgal et al. [108]. The specimen of Kinorhyncha family Pycnophyes sp., was collected from the west coast of India [108]. Although earlier work was carried out by Higgins [2] [21] in the Indian Ocean, the continuity of research was found to be negligible. According Vekatraman et al. [109] only nine species were reported in India till 1979. After 37 years, according to Jeeva and Mohan [110], works on Kinoryncha in India has taken a new shape with a first report of Echinoderes setiger (Greeff, 1869) from Andaman Islands (India). Thus, currently there are only 16 species (Table 4) that are identified in Indian waters.

Supplementary references where the species records are available given in [111] - [127].

8. Conclusion

The above list has a detailed status of all the species regarding the acceptance, non acceptance of species names and their acceptance as nomen dubium and taxon inquirendum in the last five years (i.e., after 2013), based on WoRMS [86] database and Nehaus [1]. This checklist record includes a total of 271 identified species out of which almost 82 species were published in articles. This research article could be useful for both present and future studies of Kinorhyncha, especially for controversial species status. Since, there is not much work on Kinorhyncha in India, this work could help initiate further research.

Acknowledgements

The authors thank Dr. Hiroshi Yamasaki (Japan) for his tireless help and suggestions. They also acknowledge the Head, Department of Ocean Studies and Marine Biology and authorities of Pondicherry University for providing the facilities to execute this project under the Ministry of Environment, Forest and Climatic Change (MoEFCC), New Delhi, through AICOPTAX funded programme.

Conflicts of Interest

The authors declare no conflicts of interest regarding the publication of this paper.

References

[1]	Neuhaus, B. (2013) Kinorhyncha (= Echinodera). In: Schmidt-Rhaesa, A., Ed., Handbook of Zoology, Gastrotricha, Cycloneuralia and Gnathifera, Volume 1: Nematomorpha, Priapulida, Kinorhyncha, Loricifera, Walter de Gruyter, Berlin, 181-348. https://doi.org/10.1515/9783110272536.181
[2]	Horn, T.D. (1978) The Distribution of Echinoderes coulli (Kinorhyncha) along an Interstitial Salinity Gradient. Transactions of the American Microscopical Society, 97, 586-589. https://doi.org/10.2307/3226174
[3]	Dujardin, F. (1851) Observations zoologies I. Sur un petit animal marin, l’Echinodère, formant un type intermédiaire entre les Crustacés et les Vers. Annales des sciences naturelles, Zoologie, Ser 3, 15, 158-160.
[4]	Zelinka, C. (1894) über die Organisation von Echinoderes. Verhandlungen der Deutschen Zoologischen Gesellschaft, 4, 46-49.
[5]	Zelinka, C. (1896) Demonstration von Tafeln der Echinoderes-Monographie. Verhandlungen der Deutschen Zoologischen Gesellschaft, 6, 197-199.
[6]	Zelinka, C. (1907) Zur Kenntnis der Echinoderen. Zoologischer Anzeiger, 32, 130-136.
[7]	Zelinka, C. (1908) Zur Anatomie der Echinoderen. Zoologischer Ameiger, 33, 629-647.
[8]	Zelinka, C. (1912) Die Spermatozoen der Echinoderen und ihre Genese. In: Stummer-Traunfels, R.R.V., Ed., Verhandlungen des VIII. Internationalen Zoologen-Kongresses zu Graz, Gustav Fischer, Jena, 520-527.
[9]	Zelinka, C. (1928) Monographie der Echinodera. Verlag Wilhelm Engelmann, Leipzig.
[10]	Reinhard, Z. (1885) Kinorhyncha (Echinoderes), leur structure anatomique et leur place dans le systeme. Travaux de la Societe des naturalistes a l’Universite Imperiale de Kharkow, 19, 205-305.
[11]	Reinhard, W. (1887) Kinorhyncha (Echinoderes), ihr anatomischer Bau und ihre Stellung im System. Zeitschrift fur wissenschaftlicheZoologie, 45, 401-467.
[12]	Higgins, R.P. (1960) A New Species of Echinoderes (Kinorhyncha) from Puget Sound. Transactions of the American Microscopical Society, 79, 85-91. https://doi.org/10.2307/3223976
[13]	Higgins, R.P. (1961) Three New Homalorhagid Kinorhynchs from the San Juan Archipelago, Washington. Journal of the Elisha Mitchell ScientificSociety, 77, 81-88.
[14]	Higgins, R.P. (1964) Three New Kinorhyncha from the North Carolina Coast. Bulletin of Marine Science, 14, 479-493.
[15]	Higgins, R.P. (1964) Redescription of the Kinorhynch Echinoderes remanei (Blake, 1930) Karling, 1954. Transactions of the American Microscopical Society, 83, 243-247. https://doi.org/10.2307/3224573
[16]	Higgins, R.P. (1966) Echinoderes arlis, a New Kinorhynch from the Arctic Ocean Pacific. Science, 20, 518-520.
[17]	Higins, R.P. (1966) Faunistic Studies in the Red Sea (in Winter, 1961-1962). Part II: Kinorhynchs from the Area of Al-Ghardaqa Zoologische Jahrbücher. Abteilung für Anatomie und Ontogenie der Tiere, 93, 118-126.
[18]	Higgins, R.P. (1967) The Kinorhyncha of New-Calcdunia. In: Expedition Francaise sur recifs coralliens de la Nouvelle Caledonia, Editions de la Fondation Singcr-Polignac, Paris, Vol. 2, 75-90.
[19]	Higgins, R.P. (1968) Taxonomy and Postembryonic Development of the Cryptorhagae, a New Suborder for the Mesopsammic Kinorhynch Genus Cateria. Transactions of the American Microscopical Society, 87, 21-39. https://doi.org/10.2307/3224334
[20]	Higgins, R.P. (1969) Indian Ocean Kinorhyncha: 1, Condyloderes and Sphenoderes, New Cyclorhagid Genera. Smithsonian Contributions to Zoology, 14, 1-13. https://doi.org/10.5479/si.00810282.14
[21]	Higgins, R.P. (1969) Indian Ocean Kinorhyncha, 2: Neocentrophyidae, a New Homalorhagid Family. Proceedings of the BiologicalSociety of Washington, 87, 113-128.
[22]	Higgins, R.P. (1977) Two New Species of Echinoderes (Kinorhyncha) from South Carolina. Transactions of the American Microscopical Society, 96, 340-354. https://doi.org/10.2307/3225864
[23]	Higgins, R.P. (1977) Redescription of Echinoderes dujardinii (Kinorhyncha) with Descriptions of Closely Related Species. Smithsonian Contributions to Zoology, 248, 1-26. https://doi.org/10.5479/si.00810282.248
[24]	Higgins, R.P. (1978) Echinoderes gerardi n.sp. and E. riedli (Kinorhyncha) from the Gulf of Tunis. Transactions of the American Microscopical Society, 97, 171-180. https://doi.org/10.2307/3225589
[25]	Higgins, R.P. (1982) Three New Species of Kinorhyncha from Bermuda. Transactions of the American Microscopical Society, 104, 305-316. https://doi.org/10.2307/3225748
[26]	Higgins, R.P. (1983) The Atlantic Barrier Reef Ecosystem at Carrie Bow Cay, Belize, II: Kinorhyncha. Smithsonian Institution Press, Washington DC, 1-138. https://doi.org/10.5479/si.01960768.18.1
[27]	Higgins, R.P. (1985) The Genus Echinoderes (Kinorhyncha: Cyclorhagida) from the English Channel. Journal of the Marine Biological Association, 65, 785-800. https://doi.org/10.1017/S0025315400052590
[28]	Higgins, R.P. (1986) A New Species of Echinoderes (Kinorhyncha: Cyclorhagida) from a Coarse-Sand California Beach. Transactions of the American Microscopical Society, 105, 266-273. https://doi.org/10.2307/3226298
[29]	Higgins, R.P. (1986) Kinorhyncha. In: Botosaneanu, L., Ed., Stygofauna Mundi. A Faunistic, Distributional, and Ecological Synthesis of the World Fauna Inhabiting Subterranean Waters (Including the Marine Interstitial), E.J. Brill & Dr. W. Backhuys, Leiden, 110-118.
[30]	Higgins, R.P. (1990) Zelinkaderidae, a New Family of Cyclorhagid Kinorhyncha. Smithsonian Contributions to Zoology, 500, 1-26. https://doi.org/10.5479/si.00810282.500
[31]	Higgins, R.P. (1991) Pycnophyes chukchiensis, a New Homalorhagid Kinorhynch from the Arctic Sea. Proceedings of the Biological Society of Washington, 104, 184-188.
[32]	Brown, R. and Higgins, R.P. (1983) A New Species of Kmorhynchus (Homalorhagida, Pycnophyidae) from Australia with a Redescription and Range Extension of Other Kinorhyncha from the South Pacific. Zoologica Scripta, 12, 161-169. https://doi.org/10.1111/j.1463-6409.1983.tb00561.x
[33]	Higgins, R.P. and Korczynski, R.E. (1989) Two New Species of Pycnophyes (Homalorhagida, Kmorhyncha) from the Canadian Coast of the Beaufort Sea. Canadian Journal of Zoology, 67, 2056-2064. https://doi.org/10.1139/z89-293
[34]	Higgins, R.P. and Rao, G.C. (1979) Kinorhynchs from the Andaman Islands. Zoological Journal of the Linnean Society, 67, 75-85. https://doi.org/10.1111/j.1096-3642.1979.tb01106.x
[35]	Higgins, R.P. and Kristensen, R.M. (1988) Kinorhyncha from Disko Island, West Greenland. Smithsonian Contributions to Zoology, 458, 1-56. https://doi.org/10.5479/si.00810282.458
[36]	Higgins, R.P. and Shirayama, Y. (1990) Dracoderidae, a New Family of the Cyclorhagid Kinorhyncha from the Inland Sea of Japan. Zoological Science, 7, 939-946.
[37]	Higgins, R.P. and Adrianov, A.V. (1991) Kinorhyncha from the Black Sea Redescription of Kinorhynchus paraneapolitanus. Transactions of the American Microscopical Society, 110, 328-336. https://doi.org/10.2307/3226769
[38]	Adrianov, A.V. and Higgins, R.P. (1996) Pycnophyes parasanmansis, a New Kinorhynch (Kinorhyncha. Homalorhagida Pycnophyidae) from San Juan Island. Proceedings of the Biological Society of Washington, 109, 236-247.
[39]	Pardos, F., Higgins, R.P. and Benito, J. (1998) Two New Echinoderes (Kinorhyncha, Cyclorhagida) from Spain, Including a Reevaluation of Kinorhynch Taxonomiccharacters. Zoologischer Anzeiger, 237, 195-208.
[40]	Martorelli, S. and Higgins, R.P. (2004) Kinorhyncha from the Stomach of the Shrimp Pleoticus muelleri (Bate, 1888) from Comodoro Rivadavia, Argentina. Zoologischer Anzeiger, 243, 85-98. https://doi.org/10.1016/j.jcz.2004.07.003
[41]	Neuhaus, B., Pardos, F., Sorensen, M.V. and Higgins, R.P. (2013) Redescription, Morphology, and Biogeography of Centroderes Spinosus (Reinhard, 1881) (Kinorhyncha: Cyclorhagida). Cahiers de Biologie Marine, 54, 109-131.
[42]	Neuhaus, B. and Blasche, T. (2006) Fissuroderes, a New Genus of Kmorhyncha (Cyclorhagida) from the Deep Sea and Continental Shelf of New Zealand and from the Continental Shelf of Costa Rica. Zoologischer Anzeiger, 245, 19-52. https://doi.org/10.1016/j.jcz.2006.03.003
[43]	Sorensen, M.V. (2007) A New Species of Antygomonas (Kinorhyncha: Cyclorhagida) from the Atlantic Coast of Florida, USA. Cahiers de Biologie Marine, 48, 155-168.
[44]	Sorensen, M.V., Heiner, I., Ziemer, O. and Neuhaus, B. (2007) Tubulideres seminoli gen. et sp. nov. and Zelinkaderes brightae sp. nov. (Kinorhyncha, Cyclorhagida) from Florida. Helgoland Marine Research, 61, 247-265. https://doi.org/10.1007/s10152-007-0073-8
[45]	GáOrdónez, D., Pardos, F. and Benito, J. (2008) Three New Echinoderes (Kinorhyncha, Cyclorhagida) from North Spain, with New Evolutionary Aspects in the Genus. Zoologischee Anzeiger, 247, 95-111. https://doi.org/10.1016/j.jcz.2007.07.001
[46]	Sorensen, M.V., Heiner, I. and Hansen, J.G. (2009) A Comparative Morphological Study of the Kinorhynch Genera Antygomonasand Semnoderes (Kinorhyncha: Cyclorhagida). Helgoland Marine Research, 63, 129-147. https://doi.org/10.1007/s10152-008-0132-9
[47]	Sorensen, M.V., Accogli, G. and Hansen, J.G. (2010) Postembryonic Development of Antygomonas incomitata (Kinorhyncha: Cyclorhagida). The Journal of Morphology, 271, 863-882. https://doi.org/10.1002/jmor.10844
[48]	Sorensen, M.V., Rho, H.S. and Kim, D. (2010) A New Species of Condyloderes (Cyclorhagida, Kinorhyncha) from Korea. Zoological Science, 27, 234-242. https://doi.org/10.2108/zsj.27.234
[49]	Sorensen, M.V., Pardos, F., Herranz, M. and Rho, H.S. (2010) New Data on the Genus Paracentrophyes (Homalorhagida, Kinorhyncha), with the Description of a New Species from the West Pacific. The Open Zoology Journal, 3, 42-59. https://doi.org/10.2174/1874336601003010042
[50]	Sorensen, M.V., Rho, H.S. and Kim, D. (2010) A New Species of the Rare Genus Sphenoderes (Cyclorhagida, Kinorhyncha), with Differential Notes on S. indicus Higgins, 1969. Marine Biology Research, 6, 472-484. https://doi.org/10.1080/17451000903334702
[51]	Sorensen, M.V. and Thormar, J. (2010) Wollunquaderes majkenae gen. et sp. nov. a New Cyclorhagid Kinorhynch Genus and Species from the Coral Sea, Australia. Marine Biodiversity, 40, 261-275. https://doi.org/10.1007/s12526-010-0048-x
[52]	Sorensen, M.V., Rho, H.S., Min, W.G., Kim, D. and Chang, C.Y. (2012) An Exploration of Echinoderes (Kinorhyncha: Cyclorhagida) in Korean and Neighboring Waters, with the Description of Four New Species and a Redescription of E. tchefouensis Lou, 1934. Zootaxa, 3368, 161-196. https://doi.org/10.11646/zootaxa.3368.1.8
[53]	Sánchez, N., Pardos, F., Herranz, M. and Benito, J. (2011) Pycnophyes dolichurus sp. nov. and P. aulacodes sp. nov. (Kinorhyncha, Homalorhagida, Pycnophyidae), Two New Kinorhynchs from Spain with a Reevaluation of Homalorhagid Taxonomic Characters. Helgoland Marine Research, 65, 319-334. https://doi.org/10.1007/s10152-010-0226-z
[54]	Sánchez, N., Herranz, M., Benito, J. and Pardos, F. (2012) Kinorhyncha from the Iberian Peninsula: New Data from the First Intensive Sampling Campaigns. Zootaxa, 3402, 24-44. https://doi.org/10.11646/zootaxa.3402.1.2
[55]	Herranz, M., Thormar, J., Benito, J., Sánchez, N. and Pardos, F. (2012) Meristoderes gen. nov., a New Kinorhynch Genus, with the Description of Two New Species and Their Implications for Echinoderid Phylogeny (Kinorhyncha: Cyclorhagida, Echinoderidae). Zoologischer Anzeiger, 251, 161-179. https://doi.org/10.1016/j.jcz.2011.08.004
[56]	Herranz, M., Sánchez, N., Pardos, F. and Higgins, R.P. (2013) New Kinorhyncha from Florida Coastal Waters. Helgoland Marine Research, 68, 59-87. https://doi.org/10.1007/s10152-013-0369-9
[57]	Zotto, M.D., Di Domenico, M., Garraffoni, A. and Sorensen, M.V. (2013) Franciscideres gen. nov. a New, Highly Aberrant Kinorhynch Genus from Brazil, with an Analysis of Its Phylogenetic Position. Systematics and Biodiversity, 11, 303-321. https://doi.org/10.1080/14772000.2013.819045
[58]	Sorensen, M.V. (2014) First Account of Echinoderid Kinorhynchs from Brazil, with the Description of Three New Species. Marine Biodiversity, 4, 251-274. https://doi.org/10.1007/s12526-013-0181-4
[59]	Herranz, M. and Pardos, F. (2013) Fissuroderes sorenseni sp. nov. and Meristoderes boylei sp. nov. First Atlantic Recording of Two Rare Kinorhynch Genera, with New Identification Keys. Zoologischer Anzeiger, 253, 93-111. https://doi.org/10.1016/j.jcz.2013.09.005
[60]	Sánchez, N., Rho, H.S., Min, W.G., Kim, D. and Sorensen, M.V. (2013) Four New Species of Pycnophyes (Kinorhyncha: Homalorhagida) from Korea and the East China Sea. Scientia Marina, 77, 353-380. https://doi.org/10.3989/scimar.03769.15A
[61]	Thomsen, V.G., Rho, H.S., Kim, D. and Sorensen, M.V. (2013) A New Species of Dracoderes (Kinorhyncha: Dracoderidae) from Korea Provides Further Support for a Dracoderid-Homalorhagid Relationship. Zootaxa, 3682, 133-142. https://doi.org/10.11646/zootaxa.3682.1.6
[62]	Sánchez, N., Herranz, M., Benito, J. and Pardos, F. (2014) Pycnophyes almansae sp. nov. and Pycnophyes lageria sp. nov., Two New Homalorhagid Kinorhynchs (Kinorhyncha, Homalorhagida) from the Iberian Peninsula, with Special Focus on Introvert Features. Marine Biology Research, 10, 17-36. https://doi.org/10.1080/17451000.2013.793804
[63]	Sánchez, N., Pardos, F. and Sorensen, M.V. (2014) A New Kinorhynch Genus, Mixtophyes (Kinorhyncha: Homalorhagida), from the Guinea Basin Deep-Sea, with New Data on the Family Neocentrophyidae. Helgoland Marine Research, 68, 221-239. https://doi.org/10.1007/s10152-014-0383-6
[64]	Sánchez, N., Pardos, F. and Sorensen, M.V. (2014) Deep-Sea Kinorhyncha: Two New Species from the Guinea Basin, with Evaluation of an Unusual Male Feature. Organisms Diversity & Evolution, 14, 349-361. https://doi.org/10.1007/s13127-014-0182-6
[65]	Neuhaus, B., Pardos, F., Sorensen, M.V. and Higgins, R.P. (2014) New Species of Centroderes (Kinorhyncha: Cyclorhagida) from the Northwest Atlantic Ocean, Life Cycle, and Ground Pattern of the Genus. Zootaxa, 3901, 1-69. https://doi.org/10.11646/zootaxa.3901.1.1
[66]	Yamasaki, H. and Fujimoto, S. (2014) Two New Species in the Echinoderes coulli Group (Echinoderidae, Cyclorhagida, Kinorhyncha) from the Ryukyu Islands, Japan. ZooKeys, 382, 2752. http://zookeys.pensoft.net/articles.php?id=3386 https://doi.org/10.3897/zookeys.382.6761
[67]	Yamasaki, H. (2015) Two New Species of Dracoderes (Kinorhyncha: Dracoderidae) from the Ryukyu Islands, Japan, with a Molecular Phylogeny of the Genus. Zootaxa, 3980, 359-378. https://doi.org/10.11646/zootaxa.3980.3.2
[68]	Altenburger, A., Rho, H.S., Chang, C.Y. and Sorensen, M.V. (2015) Zelinkaderes yong sp. nov. from Korea—The First Recording of Zelinkaderes (Kinorhyncha: Cyclorhagida) in Asia. Zoological Studies, 54, 1-13. https://doi.org/10.1186/s40555-014-0103-6
[69]	Zotto, M.D. (2015) Antygomonas caeciliae, a New Kinorhynch from the Mediterranean Sea, with Report of Mitochondrial Genetic Data for the Phylum. Marine Biology Research, 11, 689-702.
[70]	Adrianov, A.V. and Maiorova, A.S. (2016) Condyloderes kurilensis sp. nov. (Kinorhyncha: Cyclorhagida) a New Deep Water Species from the Abyssal Plain near the Kuril_Kamchatka Trench. Russian Journal of Marine Biology, 42, 11-19. https://doi.org/10.1134/S1063074016010028
[71]	Landers, S.C. and Sorensen, M.V. (2016) Two New Species of Echinoderes (Kinorhyncha, Cyclorhagida), E. romanoi sp. n. and E. joyceae sp. n., from the Gulf of Mexico. Zoo Keys, 594, 51-71. https://doi.org/10.3897/zookeys.594.8623
[72]	Sorensen, M.V., Gasiorowski, L., Randso, P.V., Sánchez, N. and Neves, R.C. (2016) First Report of Kinorhynchs from Singapore, with the Description of Three New Species. Raffles Bulletin of Zoology, 64, 3-27.
[73]	Yamasaki, H. (2016) Two New Echinoderes Species (Echinoderidae, Cyclorhagida, Kinorhyncha) from Nha Trang, Vietnam. Zoological Studies, 55, 32.
[74]	Yildiz, N.O., Sorensen, M.V. and Karaytug, S. (2016) A New Species of Cephalorhyncha Adrianov, 1999 (Kinorhyncha: Cyclorhagida) from the Aegean Coast of Turkey. Helgoland Marine Research, 70, 24. https://doi.org/10.1186/s10152-016-0476-5
[75]	Sánchez, N., García-Herrero, A., García-Gómez, G. and Pardos, F. (2017) A New Species of the Recently Established Genus Setaphyes (Kinorhyncha, Allomalorhagida) from the Mediterranean with an Identification Key. Marine Biodiversity, 48, 249-258. https://doi.org/10.1007/s12526-017-0651-1
[76]	Sorensen, M.V., Rohal, M. and Thistle, D. (2018) Deep-Sea Echinoderidae (Kinorhyncha: Cyclorhagida) from the Northwest Pacific. European Journal of Taxonomy, 456, 1-75. https://doi.org/10.5852/ejt.2018.456
[77]	Yamasaki, H. (2016) Ryuguderes iejimaensis, a New Genus and Species of Campyloderidae (Xenosomata: Cyclorhagida: Kinorhyncha) from a Submarine Cave in the Ryukyu Islands, Japan. Zoologischer Anzeiger—A Journal of Comparative Zoology, 265, 69-79. https://doi.org/10.1016/j.jcz.2016.02.003
[78]	Sorensen, M.V. and Landers, S.C. (2017) New Species of Semnoderidae (Kinorhyncha: Cyclorhagida: Kentrorhagata) from the Gulf of Mexico. Marine Biodiversity, 48, 327-355. https://doi.org/10.1007/s12526-017-0728-x
[79]	Yamasaki, H., Neuhaus, B. and George, K.H. (2018) New Species of Echinoderes (Kinorhyncha: Cyclorhagida) from Mediterranean Seamounts and from the Deep-Sea Floor in the Northeast Atlantic Ocean, Including Notes on Two Undescribed Species. Zootaxa, 4387, 541-566. https://doi.org/10.11646/zootaxa.4387.3.8
[80]	Yamasaki, H., Grzelak, K., Sorensen, M.V., Neuhaus, B. and George, K.H. (2018) Echinoderes pterus sp. n. Showing a Geographically and Bathymetrically Wide Distribution Pattern on Seamounts and on the Deep-Sea Floor in the Arctic Ocean, Atlantic Ocean, and the Mediterranean Sea (Kinorhyncha, Cyclorhagida). ZooKeys, 771, 15-40. https://doi.org/10.3897/zookeys.771.25534
[81]	Yamasaki, H., Neuhaus, B. and George, K.H. (2018) Three New Species of Echinoderidae (Kinorhyncha: Cyclorhagida) from Two Seamounts and the Adjacent Deep-Sea Floor in the Northeast Atlantic Ocean. Cahiers de Biologie Marine, 59, 79-106.
[82]	Sorensen, M.V. (2013) Phylum Kinorhyncha. Zootaxa, 3703, 63-66. https://doi.org/10.11646/zootaxa.3703.1.13
[83]	Yamasaki, H., Hiruta, S.F. and Kajihara, H. (2013) Molecular Phylogeny of Kinorhynchs. Molecular Phylogenetics and Evolution, 67, 303-310. https://doi.org/10.1016/j.ympev.2013.02.016
[84]	Sorensen, M.V., Zotto, D.M., Rho, H.S., Herranz, M., Sánchez, N., Pardos, F., et al. (2015) Phylogeny of Kinorhyncha Based on Morphology and Two Molecular Loci. PLoS ONE, 10, e0133440. https://doi.org/10.1371/journal.pone.0133440
[85]	ICZN (1999) International Code of Zoological Nomenclature, Fourth Edition. Adopted by the International Union of Biological Sciences. The International Trust for Zoological Nomenclature. http://taxonomicon.taxonomy.nl/Reference.aspx?id=5932
[86]	WoRMS (2020) Marine Speceis Database. http://www.marinespecies.org/aphia.php?p=taxdetails&id=101064
[87]	Yamasaki, H., Kajihara, H. and Mawatari, S.F. (2012) First Report of Kinorhynchs from Hokkaido, Japan, Including a New Species of Pycnophyes (Pycnophyidae: Homalorhagida). Zootaxa, 3425, 23-41. https://doi.org/10.11646/zootaxa.3425.1.2
[88]	Huys, R. and Coomans, A. (1989) Echinoderes higginsisp n (Kinorhyncha, Cyclorhagida) from the Southern North Sea with a Key to the Genus Echinoderes Clapardde. Zoologica Scripta, 18, 211-221. https://doi.org/10.1111/j.1463-6409.1989.tb00446.x
[89]	Murakami, C., Adrianov, A.V. and Shirayama, Y. (2001) Taxonomic Study of the Kinorhyncha in Japan. I Pycnophyetsu Tubuliferus Adrianov, 1989 (Kinorhyncha Homnalorhagida) from Japan. Publication Seto Marine Biological Laboratory, 39, 113-127. https://doi.org/10.5134/176298
[90]	Adrianov, A.V. and Malakhov, V.V. (1999) Cephalorhyncha of the World Ocean. KMK Scientific Press, Moscow, 1-400.
[91]	Sánchez, N. (2015) Advances in the Systematics and Phylogeny of Allomalorhagidkinorhynchs (Kinorhyncha, Allomalorhagida). PhD Thesis, Universidad Complutense de Madrid, 1-281.
[92]	Adrianov, A.V., Murakami, C. and Shirayama, Y. (2002) Echinoderes aureusn. sp. (Kinorhyncha: Cyclorhagida) from Tanabe Bay (Honsyu Island), Japan, with a Key to Thegenus Echinoderes. Species Divers, 7, 47-66. https://doi.org/10.12782/specdiv.7.47
[93]	Yamasaki, H., Hiruta, S.F., Kajihara, H. and Dick, M.H. (2014) Two Kinorhynch Species (Cyclorhagida, Echinoderidae, Echinoderes) Show Different Distribution Patterns across Tsugaru Strait, Northern Japan. Zoological Science, 31, 421-429. https://doi.org/10.2108/zs140011
[94]	Sánchez, N. and Yamasaki, H. (2016) Two New Pycnophyidae Species (Kinorhyncha: Allomalorhagida) from Japan Lacking Ventral Tubes in Males. Zoologischer Anzeiger: A Journal of Comparative Zoology, 265, 69-79. https://doi.org/10.1016/j.jcz.2016.04.001
[95]	Sorensen, M.V., Rho, H.S., Min, W., Kim, D. and Chang, C.Y. (2013) Occurrence of the Newly Described Kinorhynch Genus Meristoderes (Cyclorhagida: Echinoderidae) in Korea, with the Description of Four New Species. Helgoland Marine Research, 67, 291-319. https://doi.org/10.1007/s10152-012-0323-2
[96]	Sorensen, M.V., Herranz, M., Rho, H.S., Min, W., Yamasaki, H., Sánchez, N. and Pardos, F. (2012) On the Genus Dracoderes Higgins & Shirayama, 1990 (Kinorhyncha: Cyclorhagida) with a Redescription of Its Type Species, D. abei, and a Description of a New Species from Spain. Marine Biology Research, 8, 210-232. https://doi.org/10.1080/17451000.2011.615328
[97]	Lemburg, C. (2002) A New Kinorhynch Pycnophyes australensis sp. n. (Kinorhyncha: Homalorhagida: Pycnophyidae) from Magnetic Island, Australia. Zoologischer Anzeiger, 241, 173-189. https://doi.org/10.1078/S0044-5231(04)70072-8
[98]	Sorensen, M.V. and Landers, S.C. (2014) Two New Species of Echinoderes (Kinorhyncha: Cyclorhagida) from the Gulf of Mexico. Frontiers in Marine Science, 1, 1-18. https://doi.org/10.3389/fmars.2014.00008
[99]	Zotto, M.D. and Todaro, M.A. (2016) Kinorhyncha from Italy, a Revision of the Current Checklist and an Account of the Recent Investigations. Zoologischer Anzeiger, 265, 90-107.
[100]	Lundbye, H., Rho, H.S. and Sorensen, M.V. (2011) Echinoderes rex n. sp. (Kinorhyncha: Cyclorhagida), the Largest Echinoderes Species Found So Far. Scientia Marina, 75, 45-51. https://doi.org/10.3989/scimar.2011.75n1041
[101]	Pardos, F., Sánchez, N. and Herranz, M. (2016) Two Sides of a Coin: The Phylum Kinorhyncha in Panama. I. Caribbean Panama. Zoologischer Anzeiger, 265, 3-25. https://doi.org/10.1016/j.jcz.2016.06.005
[102]	Pardos, F., Herranz, M. and Sánchez, N. (2016) Two Sides of a Coin: The Phylum Kinorhyncha in Panama. II. Pacific Panama. Zoologischer Anzeiger, 265, 26-47. https://doi.org/10.1016/j.jcz.2016.06.006
[103]	Sorensen, M.V., Herranz, M. and Landers, S.C. (2016) A New Species of Echinoderes (Kinorhyncha: Cyclorhagida) from the Gulf of Mexico, with a Redescription of Echinoderes bookhouti Higgins, 1964. Zoologischer Anzeiger: A Journal of Comparative Zoology, 265, 48-68. https://doi.org/10.1016/j.jcz.2016.04.004
[104]	Neves, R.C., Sorensen, M.V. and Herranz, M. (2016) First Account on Kinorhynchs from Portugal, with the Description of Two New Species: Echinoderes lusitanicus sp. nov. and E. reicherti sp. nov. Marine Biology Research, 12, 455-470. https://doi.org/10.1080/17451000.2016.1154973
[105]	Sorensen, M.V. and Pardos, F. (2008) Kinorhynch Systematics and Biology. An Introduction to the Study of Kinorhynchs, Inclusive Identification Keys to the Genera. Meiofauna Marina, 16, 21-73.
[106]	Rao, G.C. and Ganapati, P.N. (19660 Occurrence of an Aberrant Kinorhynch Cateria styx Gerlach, in Waltair Beach Sands. Current Science, 35, 212-213.
[107]	Ganapati, P.N. and Rao, G.C. (1962) Ecology of the Interstitial Fauna Inhabiting the Sandy Beaches of Waltair Coast. Journal of the Marine Biological Association of India, 4, 44-57.
[108]	Dovgal, I., Chatterjee, T., Ingole, B. and Nanajkar, M. (2008) First Report of Limnoricus ponticus Dovgal & Lozowskiy (Ciliophora: Suctorea) as Epibionts on Pycnophyes (Kinorhyncha) from the Indian Ocean with Key to Species of the Genus Limnoricus. Cahiers de Biologie Marine, 49, 381-385.
[109]	Venkataraman, K., Raghunanthan, C., Sivaleela, G., Choudury, S., Mondal, T. and Raghuraman, R. (2015) Released on the Occasion of “National Workshop on Lesser Known Marine Animals of India” during 11-13 June 2015 Held at ZSI. Zological Survey of India, Kolkata, 1-4.
[110]	Jeeva, C. and Mohan, P.M. (2016) A Report of Echinoderes setiger Greeff, 1869 (Kinorhyncha, Cyclorhagida) in Intertidal Zone of Port Blair. Journal of the Andaman Science Association, 21, 205-256.
[111]	Adrianov, A.V. and Malakhov, V.V. (1994) Kinorhyncha: Structure, Development, Phylogeny and Taxonomy. Nauka Publishing, Moscow, 1-262.
[112]	Adrianov, A.V. and Maiorova, A.S. (2018) Parasemnoderes intermedius gen. n., sp. n.—The First Abyssal Representative of the Family Semnoderidae (Kinorhyncha: Cyclorhagida). Russian Journal of Marine Biology, 44, 355-362. https://doi.org/10.1134/S1063074018050024
[113]	Claparede, E. (1863) Beobachtungen iiber Anatomie und Entwicklungsgeschkhte wirbelloser Tiere an der Kiiste der Normandie angestellt. Wilhelm Engelmaim, Leipzig, 120 p. https://doi.org/10.5962/bhl.title.10030
[114]	Gerlach, S.A. (1956) über einen aberranten Vertreter der Kinorhynchen aus dem Küstengrundwasser. Kieler Meeresforsch, 12, 120-124.
[115]	Grzelak, K. and Sorensen, M.V. (2018) New Species of Echinoderes (Kinorhyncha: Cyclorhagida) from Spitsbergen, with Additional Information about Known Arctic Species. Marine Biology Research, 14, 113-147. https://doi.org/10.1080/17451000.2017.1367096
[116]	Herranz, M., Yangel, E. and Leander, B.S. (2017) Echinoderes hakaiensis sp. nov.: A New Mud Dragon (Kinorhyncha, Echinoderidae) from the Northeastern Pacific Ocean with the Redescription of Echinoderes pennaki Higgins, 1960. Marine Biodiversity, 48, 303-325. https://doi.org/10.1007/s12526-017-0726-z
[117]	Landers, S.C. and Sorensen, M.V. (2018) Echinoderes sylviae n. sp. (Kinorhyncha, Cyclorhagida), from the Gulf of Mexico, with Comparative Notes on a Similar Species Echinoderes spinifurca. Bulliton of Marine Science, 94, 1499-1514. https://doi.org/10.5343/bms.2017.1167
[118]	Nebelsick, M. (1990) Antygomonasin comitata gen et sp n. (Cyclorhagida, Kinorhyncha) and Its Phylogenetic Relationships. Zoologischer Anzeiger, 19, 143-152. https://doi.org/10.1111/j.1463-6409.1990.tb00248.x
[119]	Remane, A. (1929) Rotatoria. In: Grimpe and Wagler, Eds., Die Tierwelt der Nordund Ostsee, Part VIIe, AkademischeVerlagsgesellschaft, Leipzig, 1-156.
[120]	Sánchez, N., Yamasaki, H., Pardosa, F., Sorensen, M.V. and Martinezd, A. (2016) Morphology Disentangles the Systematics of a Ubiquitous but Elusive Meiofaunal Group (Kinorhyncha: Pycnophyidae). Cladistics, 32, 479-505.
[121]	Sánchez, N., García-Herrero, A., García-Gómez, G. and Pardos, F. (2018) A New Species of the Recently Established Genus Setaphyes (Kinorhyncha, Allomalorhagida) from the Mediterraneanwith an Identification Key. Marine Biodiversity, 48, 249-258. https://doi.org/10.1007/s12526-017-0651-1
[122]	Sorensen, M.V. (2008) A New Kinorhynch Genus from the Antarctic Deep-Sea and a New Species of Cephalorhyncha from Hawaii (Kinorhyncha: Cyclorhagida: Echinoderidae). Organisms, Diversity & Evolution, 8, 230e1-230e18. https://doi.org/10.1016/j.ode.2007.11.003
[123]	Sorensen, M.V. and Rho, H.S. (2009) Triodontoderes anulap gen. et sp. nov. A New Cyclorhagid Kinorhynch Genus and Species from Micronesia. JMBA, 89, 1269-1279. https://doi.org/10.1017/S0025315409000526
[124]	Sorensen, M.V. and Grzelak, K. (2018) New Mud Dragons from Svalbard: Three New Species of Cristaphyes and the First Arctic Species of Pycnophyes (Kinorhyncha: Allomalorhagida: Pycnophyidae). PeerJ, 6, e5653. https://doi.org/10.7717/peerj.5653
[125]	Timm, R.W. (1958) Two New Species of Echinoderiderella (Phylum Kinorhyncha) from the Bay of Bengal. Bombay Natural History Society, 55, 107-109.
[126]	Yamasaki, H. and Durucan, F. (2018) Echinoderes antalyaensis sp. nov. (Cyclorhagida: Kinorhyncha) from Antalya, Turkey, Levantine Sea, Eastern Mediterranean Sea. Species Diversity, 23, 193-207. https://doi.org/10.12782/specdiv.23.193
[127]	Zelinka, C. (1913) Die Echinoderen der Deutschen Südpolar-Expedition 1901-1903. Deutsche Südpolar-Expedition XIV, Zoologie VI, 419-437.