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. 2021 Apr 8;9:e62343. doi: 10.3897/BDJ.9.e62343

A small collection of Endeis juveniles (Arthropoda: Pycnogonida: Endeidae) sorted from the fouling organisms on the R/V Dayangyihao

Jianjia Wang 1,2, Dong Sun 3, Peng Tian 1, Dinyong Huang 1, Wentao Niu 1,✉, Feng Zhang 2,✉
PMCID: PMC8050013  PMID: 33867802

Abstract

Background

Endeis straughani Clark, 1970 was originally described from Queensland, Australia. Its range was extended to Ghana, West Africa when E. picta Bamber, 1979 was synonymised with E. straughani by Staples (1982). The current paper extends this range further, to include Port Louis, Mauritius.

New information

Five immature individuals gathered amongst hydroids during the 5th leg of the DY125-34 expedition were tentatively identified as E. straughani juveniles. Since these were collected from the fouling community on the ship’s hull, they probably originated in Port Louis (Mauritius) when the ship was docked there.

Keywords: Indian Ocean, Mauritius, new record, fouling communities on ship hulls

Introduction

The genus Endeis Philippi, 1843 includes 18 species distributed widely, except from the Arctic Ocean (Takahashi et al. 2007, Bamber et al. 2020). Stock (1968) established a key to 13 species, while Fry and Hedgpeth (1969) set up a key to seven species and there were also some regional keys for those species occurring in South Africa (Barnard 1954), Middle America (Child 1979), Japan (Nakamura and Child 1983), Colombia Caribbean Coast (Müller and Krapp 2009) and north-east Atlantic (Bamber 2010). After Stock’s key, seven Endeis species were described by Stock (1970), Clark (1970), Pushkin (1976), Bamber (Bamber 1979, Bamber 1992), Takahashi et al. (2007) and Müller and Krapp (2009), respectively, but Endeis picta Bamber, 1979 was synonymised with Endeis straughani Clark, 1970 (Staples 1982).

During the 5th leg of the DY125-34 expedition, which was returning to China from its work zone in the SWIR (Southwest Indian Ocean Ridge), five juvenile Endeis specimens were collected along with the hydroid, Leptothecata Cornelius, 1992 while sampling the water for zooplankton. Giving the difficulties associated with identifying juvenile specimens, this small collection (Fig. 1 A, B) was tentatively identified as Endeis straughani Clark, 1970 by their compact trunk, robust legs, tubercles located on the femur and on the second tibiae.

Figure 1.

Figure 1.

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Endeis straughani, (TIO2014DY34-5.003): A. trunk, dorsal view. (TIO2014DY34-5.002): B. trunk, ventral view. (TIO2014DY34-5.001): C. trunk, dorsal view; D. trunk, lateral view; E. leg 1; F. tarsus, propodus and claws of leg 1, enlarged, the arrow points to the obliquely short heel spine; G. tarsus, propodus and claws of leg 2, enlarged, the arrow points to the obliquely short heel spine. (TIO2014DY34-5.002): H. cephalon, ventral view, the arrow points to the oviger bud. Scale bars A and B = 1 mm; C, D and E = 0.5 mm; F, G and H= 0.2 mm.

Materials and methods

During the 5th leg (from 5/7/2015 to 5/12/2015) of the DY125-34 expedition, on its return trip to China from the work zone in SWIR, the expedition continued to collect zooplankton samples. These samples were collected by pumping seawater through a pipe which had its intake located 3 m below the surface and the outlet of the pipe was wrapped in a 20 µm mesh net to ensure the minimum size of samples collected. Sampling occurred over a 12-hour period each day. At one point during the return trip, several juvenile specimens of Endeis were accidentally collected along with several hydroids. Stock (1968), Clark (1970), Bamber (1979)and Staples (1982)were used to identify the Endeis specimens.

The five pycnogonids (No. TIO2014DY34-5.001-005), along with the hydroids, were preserved in 90% ethanol and stored at the Third Institute of Oceanography, Ministry of Natural Resources, China. Photographs were taken with an Auto-montage system on a Leica M205 FA stereomicroscope and z-stacks were created with the LAS software (Version 3.8). Measurements of the pycnogonids were made axially, dorsally for the trunk, laterally for the proboscis and legs and are given in mm.

Taxon treatments

Endeis straughani

Clark, 1970

353009C7-CB41-54E1-B160-112DB3BF49E2

Materials

  1. Type status: Other material. Occurrence: individualID: TIO2014DY34-5.001; individualCount: 1; lifeStage: juvenile; Taxon: scientificName: Endeis straughani Clark, 1970; kingdom: Animalia; phylum: Arthropoda; class: Pycnogonida; order: Pantopoda; family: Endeidae; genus: Endeis; Location: locationID: Mauritius; verbatimCoordinates: 71.5E; verbatimLatitude: 30.3S; Identification: identifiedBy: Jianjia Wang; Event: year: 2015; month: 5; day: 7; habitat: amongst hydroids

  2. Type status: Other material. Occurrence: individualID: TIO2014DY34-5.002; individualCount: 1; lifeStage: juvenile; Taxon: scientificName: Endeis straughani Clark, 1970; kingdom: Animalia; phylum: Arthropoda; class: Pycnogonida; order: Pantopoda; family: Endeidae; genus: Endeis; Location: locationID: Mauritius; verbatimCoordinates: 71.5E; verbatimLatitude: 30.3S; Identification: identifiedBy: Jianjia Wang; Event: year: 2015; month: 5; day: 7; habitat: amongst hydroids

  3. Type status: Other material. Occurrence: individualID: TIO2014DY34-5.003; individualCount: 1; lifeStage: juvenile; Taxon: scientificName: Endeis straughani Clark, 1970; kingdom: Animalia; phylum: Arthropoda; class: Pycnogonida; order: Pantopoda; family: Endeidae; genus: Endeis; Location: locationID: Mauritius; verbatimCoordinates: 80.4E; verbatimLatitude: 22.3S; Identification: identifiedBy: Jianjia Wang; Event: year: 2015; month: 5; day: 12; habitat: amongst hydroids

  4. Type status: Other material. Occurrence: individualID: TIO2014DY34-5.004; individualCount: 1; lifeStage: juvenile; Taxon: scientificName: Endeis straughani Clark, 1970; kingdom: Animalia; phylum: Arthropoda; class: Pycnogonida; order: Pantopoda; family: Endeidae; Location: locationID: Mauritius; verbatimCoordinates: 80.4E; verbatimLatitude: 22.3S; Identification: identifiedBy: Jianjia Wang; Event: year: 2015; month: 5; day: 12; habitat: amongst hydroids

  5. Type status: Other material. Occurrence: individualID: TIO2014DY34-5.005; individualCount: 1; lifeStage: juvenile; Taxon: scientificName: Endeis straughani Clark, 1970; kingdom: Animalia; phylum: Arthropoda; class: Pycnogonida; order: Pantopoda; family: Endeidae; genus: Endeis; Location: locationID: Mauritius; verbatimCoordinates: 80.4E; verbatimLatitude: 22.3S; Identification: identifiedBy: Jianjia Wang; Event: year: 2015; month: 5; day: 12; habitat: amongst hydroids

Notes

Identification

TIO2014DY34-5.001. Trunk glabrous, completely segmented. Collar with flat protuberances laterally. Cephalon with two short spines distally. Lateral processes separated by slightly more than their own diameter, each with 1-3 short distal dorsal spines. Ocular tubercle taller than its base diameter, with pointed peak; two pairs of eyes pigmented distinctly. Abdomen pointing slightly backwards, almost as high as ocular tubercle, with two lateral spines distally (Fig. 1 C, D).

Proboscis barrel-shaped, leaning downwards at about 45 degrees, little longer than half of the trunk, slightly inflated at proximal third, with few short setae along the length and dense short setae around the mouth (Fig. 1 C, D).

Legs slender (Fig. 1 E). First coxa short, second coxa 2 times as long as first or third coxa, with some short setae ventrally. The main articles with setae sparsely dorsally and laterally; femur slightly longer than first tibia, each with one long seta located on the distal tubercle; second tibia longest, with one long setae distally. Tarsus small, subtriangular, with one spine and few setae ventrally. Propodus gently curved, with some short setae dorsally and three long setae distally; heel prominent, with 2-3 robust spines of increasing length distally, with one obliquely short spine (Fig. 1 F, G); sole with 4-6 spines and some slender setae. Main claw stout, half the length of propodus; auxiliary claws slender, almost half of main claw.

Measurements of TIO2014DY34-5.001 in mm: trunk length from the anterior margin of the cephalon to the tip of 4th lateral processes 1.34; width across second lateral processes 0.68; proboscis length 0.76; abdomen length 0.25. First leg: coxa-1 0.17, coxa-2 0.34, coxa-3 0.18, femur 0.98, tibia-1 0.84, tibia-2 1.04, tarsus 0.06, propodus 0.51, main claw 0.25, auxiliary claw 0.12.

Trunk length (TL) and Trunk Width (TW) of other specimens: TIO2014DY34-5.002 (TL 1.29; TW 0.75), TIO2014DY34-5.003 (TL 1.03; TW 0.58), TIO2014DY34-5.004 (TL 0.99; TW 0.57), TIO2014DY34-5.005 (TL 0.41; TW 0.33).

Distribution

The type location for E. straughani is Queensland, Australia (Clark 1970). Bamber (1979) described E. picta from the coast of Ghana, West Africa which has since been synonymised with E. straughani by Staples (1982), thus greatly expanding the previous known range for this species. Our specimens were inadvertently collected from the fouling community on the expedition ship’s hull which probably originated from Port Louis, Mauritius, where the ship had previously been docked, expanding the species range even further.

Remarks

Identifying the juvenile Endeis specimens was not an easy task, especially since there were no adult males collected, which would have provided information on ovigers and cement glands that are very important for determining species in this genus. Our juvenile specimens agreed generally with the descriptions given by Clark (1970), Bamber (1979) and Staples (1982) and were especially consistent with the sub-adult characteristics mentioned by Staples (1982, p. 462). In addition, lateral process intervals, along with neck and lateral process spines and the variable number of heel spines in a single specimen, a characteristic also present on the adults described in Staples (1982) and which has not been reported for other Endeis species, added confirmation that these specimens were E. straughani or a very close relative.

Almost nothing is known about the Endeis life cycle, other than an incomplete description of the life cycle of Endeis spinosa (Montagu, 1808) by Dogiel (1913, Taf. XIX, figs. 1-4 and 7-8), who described the protonymphon larva and several developmental stages in this species. According to the four distinct types of pycnogonid postembryonic development which were characterised by Bain (2003), our Endeis specimens probably have the encysted larva type of development, even though we did not examine the hydroids in order to look for the earlier encysted stages.

Three specimens (TIO2014DY34-5.002, TIO2014DY34-5.003 and TIO2014DY34-5.004) have oviger buds (Fig. 1H) and show variations in the length of trunk (range from 0.99 mm to 1.29 mm) and transparency of the cuticle. Of the specimens with oviger buds, which will become adult males, the oldest juvenile (TIO2014DY34-5.002) is larger than the other two individuals and is no longer quite as transparent (Fig. 1B). The largest specimen (TIO2014DY34-5.001) is probably 1 or 2 moults away from the adult stage (Fig. 1C-G).

In the absence of a complete life cycle to compare these specimens and based on the presence of four pairs of legs (4th pair still not completely developed) and also the presence of oviger buds in several of the specimens, they are probably at least 1 or 2 moults away from becoming adults (Dogiel 1913, Bain 2003, Lovely 2005).

Endeis straughani can be distinguished from other similar Endeis species in the same region (Stock 1965, Stock 1974) as follows: E. clipeata (Möbius, 1902) has an apical cylindrical process on the propodus; E. meridionalis (Böhm, 1879) has distorted femurs and E. mollis (Carpenter, 1904) has widely separated lateral processes and no spurs on the main leg segments. Staples (1982) pointed out the characteristics for distinguishing E. straughani from E. biseriata Stock, 1968 which has widely separated lateral processes (nearly three times the diameter of a single lateral process).

Stock (1970) recorded two Endeis species, Endeis pauciporosa Stock, 1970 and Endeis flaccida Calman, 1923 from the Gulf of Aqaba and E. flaccida also occurred in the Aden Habour (Stock 1968). Endeis pauciporosa and E. flaccida can be easily distinguished from E. straughani since they have distorted femurs and alimentary diverticula in the legs with numerous branched caeca, respectively.

Endeis viridis Pushkin, 1976, found in the Crozet Archipelago and Kerguelen Islands (Pushkin 1976, Pushkin 1993), can be distinguished from E. straughani by having distinctly slender legs and relatively long auxiliary claws, more than half the length of the main claw.

The specimens sustained some damage, such as unnaturally distorted tibiae and other kinds of damage during collecting, probably due to the pumping actions of the collecting apparatus (Fig. 1 A, B and E).

Clark’s specimens (Clark 1970) retained a bright green colour after being preserved in alcohol and our specimens showed a range from bright purple to nearly transparent after being in alcohol for some time.

Discussion

Takahashi et al. (2007) indicated that most species of Endeis live in shallow waters, although some have been found on floating seaweed. Considering that the intake was fitted with an iron mesh and no seaweed or other attached objects were gathered, we speculate that our specimens were from the fouling communities attached to the ship's hull or to the collecting pipe. The R/V “Dayangyihao” had been defouled before sailing from Sanya (China) and only docked in Port Louis (Mauritius) four times during the expedition (Fig. 2). The hydroids (Order Leptothecata Cornelius, 1992) and the pycnogonids had not previously been recorded from Mauritius before, according to the Mauritius Oceanography Institute (2007) and, if they turn out to be a new species, this will expand the list of sea spiders known from Mauritius.

Figure 2.

Figure 2.

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The sampling stations and the docking position and duration of the R/V in the “DY125-34” expedition. ? the sampling location in 05/07/2015; ? the sampling location in 05/12/2015.

Supplementary Material

XML Treatment for Endeis straughani
BDJ.9.e62343-treatment1.xml (47.6KB, xml)

Acknowledgements

Thanks so much to Dr. Xikun Song (Xiamen University) for help in identifying the hydroids. This work was supported by the National Youth Science Foundation (Grant No. 41606207), Scientific Research Foundation of Third Institute of Oceanography, MNR (Grant No. 2019025) and China Ocean Mineral Resources Research and Development Association Program (Grant No. DY-125-02-QY-06). Thanks to Dr. Bonnie Bain and several anonymous reviewers for improving this manuscript.

Contributor Information

Wentao Niu, Email: wentaoniu@tio.org.cn.

Feng Zhang, Email: zhangfeng@hbu.cn.

References

  1. Bain B. A. Larval types and a summary of postembryonic development within the pycnogonids. Invertebrate Reproduction & Development. 2003;43(3):193–222. doi: 10.1080/07924259.2003.9652540. [DOI] [Google Scholar]
  2. Bamber R. N. A new species of Endeis (Pycnogonida) from West Africa. Zoological Journal of the Linnean Society. 1979;65(3):251–254. doi: 10.1111/j.1096-3642.1979.tb01094.x. [DOI] [Google Scholar]
  3. Bamber R. N. Some pycnogonids from the South China Sea. Asian Marine Biology. 1992;9:193–203. [Google Scholar]
  4. Bamber R. N., Costa A. C. The pycnogonids (Arthropoda: Pycnogonida) of São Miguel Azores, with description of a new species of Anplodactylus Wilson, 1878 (Phoxichilidiidae) Açoreana. 2009;Supplement 6:167–182. [Google Scholar]
  5. Bamber R. N. Sea-spiders (Pycnogonida) of the north-east Atlantic: Keys and notes for identification of British species. Linnean Society of London and The Field Studies Council.; 2010. [Google Scholar]
  6. Bamber R. N., El Nagar A., Arango C. P., editors. Pycnobase: World Pycnogonida Database. http://www.marinespecies.org/pycnobase. [2020-12-16T00:00:00+02:00];
  7. Barnard K. H. South African Pycnogonida. Annals of the South African Museum. 1954;41(3):81–158. [Google Scholar]
  8. Child C. A. Shallow-water Pycnogonida of the Isthmus of Panama and the coasts of Middle America. Smithsonian Contributions to Zoology. 1979;293:1–86. doi: 10.5479/si.00810282.293. [DOI] [Google Scholar]
  9. Clark W. C. New Pycnogonida from Queensland. Transactions of the Royal Society of New Zealand. 1970;12(3):13–20. [Google Scholar]
  10. Dogiel V. Embryologische Studien an Pantopoden. Zeitschrift für Wissenschaftliche Zoologie. 1913;107(4):575–741. [Google Scholar]
  11. Fry W. G., Hedgpeth J. W. Pycnoginida, 1: Colossendeidae, Pycnogonidae, Endeidae, Ammotheidae. The fauna of the Ross Sea. Part 7. New Zealand Oceanographic Institute Memoir No. 49, New Zealand Department of Scientific and Industrial Research Bulletin. 1969;198:1–139. [Google Scholar]
  12. Haswell W. A. On the Pycnogonida of the Australian coast, with descriptions of new species. Proceedings Linnean Society of New South Wales. 1884;9:1021–1033. [Google Scholar]
  13. Krapp F. New records of Endeis charybdaea (Dohrn, 1881) (Pycnogonida) in the Atlantic and Mediterranean seas. Sarsia. 1975;59(1):85–94. doi: 10.1080/00364827.1975.10411290. [DOI] [Google Scholar]
  14. Lovely E. C. The Life History of Phoxichilidium tubulariae (Pycnogonida: Phoxichilidiidae) Northeastern Naturalist. 2005;12(1):77–92. doi: 10.1656/1092-6194(2005)012[0077:tlhopt]2.0.co;2. [DOI] [Google Scholar]
  15. Institute Mauritius Oceanography. Database of Marine Organisms of Mauritius. http://moi.gov.mu/marinedb. [2021-02-03T00:00:00+02:00];
  16. Müller H. G., Krapp F. The pycnogonid fauna (Pycnogonida, Arthropoda) of the Tayrona National Park and adjoining areas on the Caribbean coast of Colombia. Zootaxa. 2009;2319(1):1–138. doi: 10.11646/zootaxa.2319.1.1. [DOI] [Google Scholar]
  17. Nakamura K., Child C. A. Shallow-water Pycnogonida of the Izu Peninsula, Japan. Smithsonian Contributions to Zoology. 1983;386:1–71. doi: 10.5479/si.00810282.386. [DOI] [Google Scholar]
  18. Pushkin A. F. New species of Endeidae (Pantopoda) from Subantarctic. Zoologicheskii Zhurnal. 1976;55(6):923–925. Russian. [Google Scholar]
  19. Pushkin A. F. The Pycnogonida fauna of the South Ocean. Biological results of the Soviet Antarctic expeditions. Russian Academy of Sciences. Explorations of the Fauna Seas. 1993;20:1–397. Russia. [Google Scholar]
  20. Staples D. A. Pycnogonida of the Calliope River and Auckland Creek, Queensland. Memoirs of the Queensland Museum. 1982;20(3):455–471. [Google Scholar]
  21. Stock J. H. Pycnogonida from the southwestern Indian Ocean. Beaufortia. 1965;13(151):13–33. [Google Scholar]
  22. Stock J. H. Pycnogonida collected by the Galathea and Anton Bruun in the Indian and Pacific Oceans. Videnskabelige Meddelelser fra Dansk Naturhistoriske Forening i Kjøbenhavn. 1968;131:7–65. [Google Scholar]
  23. Stock J. H. A new species of Endeis and other pycnogonid records from the Gulf of Aqaba. Bulletin Zoologisch Museum. 1970;2:1–4. [Google Scholar]
  24. Stock J. H. Medio- and infralittoral Pycnogonida collected during the I.I.O.E. near the landbase on Nossi-Be, Madagascar. Bulletin Zoologisch Museum. 1974;4:11–18. [Google Scholar]
  25. Takahashi Yoshie, Dick Matthew H., Mawatari Shunsuke F. Sea spiders (Arthropoda: Pycnogonida) from waters adjacent to the Nansei Islands of Japan. Journal of Natural History. 2007;41:61–79. doi: 10.1080/00222930601121783. [DOI] [Google Scholar]

Associated Data

This section collects any data citations, data availability statements, or supplementary materials included in this article.

Supplementary Materials

XML Treatment for Endeis straughani
BDJ.9.e62343-treatment1.xml (47.6KB, xml)

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