Journal of Threatened Taxa | www.threatenedtaxa.org | 26 September 2016 | 8(11): 9377–9380

 

 

 

 

Reappearance of the rare Shingle Urchin Colobocentrotus (Podophora) atratus (Camarodonta: Echinometridae) after eight decades from the rocky shore of Kodiyaghat (Port Blair), South Andaman Islands, India

Vikas Pandey 1 & T. Ganesh 2

1,2 Department of Ocean Studies and Marine Biology, Pondicherry University, Brookshabad Campus, Port Blair, Andaman & Nicobar Islands 744112, India

1 vicky2555@gmail.com, 2 tganesh.es@gmail.com (corresponding author)

 

 

 

 

 

doi: http://dx.doi.org/10.11609/jott.2406.8.11.9377-9380

 

Editor: M. Nithyanandan, Environmental Department, La Ala Al Kuwait Real Estate. Co. K.S.C., Kuwait. Date of publication: 26 September 2016 (online & print)

 

Manuscript details: Ms # 2406 | Received 04 July 2016 | Final received 31 August 2016 | Finally accepted 02 September 2016

 

Citation: Pandey, V. & T. Ganesh (2016). Reappearance of the rare Shingle Urchin Colobocentrotus (Podophora) atratus (Camarodonta: Echinometridae) after eight decades from the rocky shore of Kodiyaghat (Port Blair), South Andaman Islands, India. Journal of Threatened Taxa 8(11): 9377–9380; http://dx.doi.org/10.11609/jott.2406.8.11.9377-9380

 

Copyright: © Pandey & Ganesh 2016. Creative Commons Attribution 4.0 International License. JoTT allows unrestricted use of this article in any medium, reproduction and distribution by providing adequate credit to the authors and the source of publication.

 

Funding: This work was carried out with the Pondicherry University fellowship.

 

Conflict of Interest: The authors declare no competing interests.

 

Acknowledgements: The authors thank the authorities of Pondicherry University for providing the necessary facilities to carry out this work and for the University fellowship to Vikas Pandey, and the Zoological Survey of India, Port Blair for their help

 

 

 

 

Andaman & Nicobar Islands are situated between 6045’–13045’N & 92012’–93057’E in the south-eastern Bay of Bengal. The The Andaman group of Islands is broadly separated into three regions, viz., North Andaman, Middle Andaman and South Andaman that contributes to 30% of Indian exclusive economic zone (EEZ) and a 1,962km long coastal line. Marine faunal diversity of these Islands have not been completely explored despite the fact that the coastal zones and fringing reefs of Andaman and Nicobar Islands harbours a rich variety of echinoderms, which is approximately half the echinoderm fauna of the Indian subcontinent (Sastry 2007).

Echinoderms have always drawn the attention of scientists since early times due to their beautiful symmetrical shape and accessibility on intertidal zone (James 1983). These are exclusively marine benthic invertebrates and contains about 6,500 known species and constitutes the only major group of deuterostome invertebrates, with relatively large and pentamerous radial symmetrical body. The echinoderms that encompass a substantial group of marine organisms including sea cucumbers, sea stars, brittle stars, sea urchins, and feather stars reach highest diversity in reef environments, but are also widespread on shallow shores. Due to their wide trophic preferences as, detritivores, filter-feeders, grazers, scavengers and active predators, they play an important role in structuring benthic communities in shallow coastal reaches (Himmelman & Dutil 1991).

Investigation on echinoderms of Indian waters was initiated as early as 1743 by Plancus and Gualtire (James 1983) when they reported Acanthaster planci off Goa coast. Bell (1887) reported echinoderms from the Andaman Islands for the first time. However works on echinoderms attained momentum after the works done by James (1987). Later Julka & Das (1978) did an extensive study on shallow water starfishes of these Islands. Sastry (1998, 1999, 2001, 2002) documented many echinoderms of Andaman & Nicobar Islands, which added several new species of echinoderms to the established list from these islands.

Sea urchins fall under the class Echinoidea, are echinoderms with alimentary, reproductive, nervous and water-vascular systems enclosed within a ‘test’ or shell usually rigid (rarely flexible) made up of plates, which bear movable spines. They are one of the most common and very important component of near-shore marine benthic communities worldwide that plays a major role in regulating the abundance, distribution and species composition of marine plants through selective feeding in a variety of habitats (Hernandez et al. 2008). As prey to a variety of predators (Pearse 2006) they act as a connecting link between primary producers and carnivores. Regular sea urchins are mostly herbivores and feed on algae (Barbera et al. 2011), whereas burrowing sea urchins are detritivore deposit feeders (Lawrence 2006). These forms play an important role in bio-turbation, especially spatangoids are important in this process due to their size, abundance and mobility (Chiold 1989; Barbera et al. 2011). By feeding on algae, urchins maintain the balance between coral erosion and algal growth. They are also considered very sensitive bio-indicators (Zizka 2012) to various nutrients and heavy metal pollution.

Colobocentrotus atratus (Linnaeus, 1758), commonly known as shingle urchin or helmet urchin, under the family Echinometridae was previously named as Echinus atratus Linnaeus, 1758. Colobocentrotus (Podophora) atratus is the currently accepted name (Clark & Rowe 1971). Genus Colobocentrotus has very peculiar morphology amongst the regular echinoids. The aboral spines are reduced and similar in length, which gives an overall compact mosaic structure on the aboral side of the urchin. Whereas, oral part of the urchin is surrounded by marginal flattened spines projecting from the ambitus (Clark & Rowe 1971). The tips of marginal spines are rounded and swollen, which makes the overall external shape of the urchin smooth and resembles a limpet or helmet.

Shingle Urchin C. atratus is an occupant of extreme wave swept areas of intertidal zone throughout the Indo-west Pacific (Santos & Flammang 2008), and possess significant medicinal properties. Albeit their high abundance in coastal waters of Hawaii, they were conferred the title of nationally endangered species by the Government of Hawaii (McCormack 2007). This species was never reported from the mainland coast of India. Even from the Andaman Islands where this species was reported for the first time (Sastry 2005), no reports are available after its occurrence (only one specimen) in the year 1935. But one specimen (Sastry 1999) of C. atratus was reported from Katchal, Great Nicobar Islands, which are separated from Andaman Islands by 10 degree Channnel. The present report of five live specimens of C. atratus from the south Andaman Islands proves its rarity in occurrence.

Materials and Methods: The present study was conducted along the east coast of South Andaman. A total of six rocky shore locations were chosen for the study of Macrobenthos. Seasonal survey at every three months interval was carried out to assess the macrofaunal distribution during December 2011 to December 2014. For the collection of macrobenthic samples a quadrat of 1m2 was used (English et al. 1997). From each location 12 random quadrat samples were studied covering upper, mid and lower intertidal zones. All the macrobenthic epifaunal groups within the quadrat were enumerated at species-level in the field to estimate species diversity and abundance. Simultaneously, digital photographs were taken for further taxonomic study. For the present study site (Kodiyaghat) no specific permits were required as the location is not privately owned or protected in any way, and the present study of Shingle Urchin is not a protected species of India.

Five individuals of C. atratus were found at Kodiyaghat (11031’532”N & 92043’457”E), on an uneven rocky terrain with a number of tide pools and big rocks. This location is directly connected to open sea and subjected to extreme wave action. For the first time in the three years of study period, only during the August 2014 sampling, five individuals of Shingle Urchins were noticed towards the lower shore where the wave action was very high. At this location a thorough survey was made to find more individuals in the north-south direction (~1km, parallel to the coast), but no individuals were noticed during the survey other than the recorded five.

The individuals of C. atratus were examined for their morphological characters (viz., number of ambulacral plates, marginal flattened spines, colour of the test and spines, the size of the test, and structure of tube feet). After a thorough examination, digital photographs were obtained for later reference. Considering the sparse population of the species, no individuals were removed from this area.

Taxonomy and Discussion:

Phylum: Echinodermata

Class: Echinoidea Leske, 1778

Order: Camarodonta Jackson, 1912

Family: Echinometridae Grey, 1855

Genus: Colobocentrotus Brandt, 1835

Sub genus: Podophora Agassiz, 1840

Species: atratus (Linnaeus, 1758)

This species was recorded for the first time from the Andaman Islands by Bell (1887) and later by Clarke (1925). Sastry (2005) reported this species from Carbyn’s cove of South Andaman based on a single specimen collected in 1935. In the present study, during a continuous three-year monitoring of macrobenthic epifauna along the South Andaman coast, we recorded five live specimens of C. atratus within 0.5m2 area off Kodiyaghat (11031’532”N & 92043’457”E; Fig. 1). This urchin is dark purple in colour at aboral and light magenta at oral side and shaped like a domed limpet. The size of largest individual among the five individuals was 7.5cm whereas smallest one recorded 4.5cm in diameter. The aboral surface is composed of modified spines to form a smooth, flattened shingle-like mosaic of modified polygonal plates with a flange of flattened spines forming a close fringe around the edge. Each ambulacra contains 11 plates and 25 marginal flattened spines (Image 1). Flattened plates are an adaptation for surviving in the heavy wave-swept environment. On the oral side there is another ring of smaller flattened spines and a number of sucker tipped tube feet offering a great degree of adhesion in a heavy wave-swept environment. The species has a hard body and it is very firmly attached to the rocks and all individuals were found in a narrow flat crevice at the low water line where the regular influx of tidal water was noticed. The rounded shape and marginal flattened spines are adaptations for resisting the force of the incoming waves to which the streamlined body of the urchin offers little resistance. In addition, numerous sucker tipped tube feet on the oral side of the organism helps in firm attachment to the substratum and gives advantage over other sympatric species (Santos & Flammang 2008). The Shingle Urchin is herbivorous and mainly grazes on red coralline algae.

Flattened spines reduces the chances of its breakage and thereby energy expense of repair. Mortenson (1943) speculated that the reduced spine was an adaptation to withstand extreme hydrodynamic forces, which was later confirmed by Gallien (1986), who measured the drag enacted on exposed C. atratus and Echinometra mathaei (a co-occurring echinoid) tests. The result showed that C. atratus was at a much reduced risk of dislodgment by wave-induced hydrodynamic forces and provide an explicit example of structural adaptation. Danny & Gaylord (1995) re-examined the conclusion and showed that the morphological changes in C. atratus is predominantly to make it possible for this urchin to survive in extreme surf zone. In addition, the morphology of this urchin is ideal for holding extra water, which can be indispensable to withstand high temperature and desiccation stress at low tide.

The significant re-appearance of C. atratus after an interval of 79 years in the south Andaman Islands, with a sparse population, and no reports of the occurrence of this species from mainland coast of India, suggests that it is a species that can be considered for long-term monitoring programme.

 

 

 

 

 

 

 

 

References

Barbera, C., D. Fernández-Jover, J.L. Jimenez, D.G. Silvera, H. Hinz & J. Moranta (2011). Trophic ecology of the sea urchin Spatangus purpureus elucidated from gonad fatty acids composition analysis. Marine Environmental Research 71(4): 235–246; http://dx.doi.org/10.1016/j.marenvres.2011.01.008

Bell, F.J. (1887). Report on a collection of Echinodermata from Andaman Islands. Proceedings of Zoological Society of London 1887: 139–145; http://dx.doi.org/10.1111/j.1096-3642.1887.tb02953.x

Chiold, J. (1989). Species distributions of irregular echinoids. Biological Oceanography 6: 79–162.

Clark, A.M. & F.W.E. Rowe (1971). Monograph of Shallow-water Indo-West Pacific Echinoderms. London, Trustees of the British Museum (Natural History), i-vii, 1-238pp, pls. 1–31.

Clark, H.L. (1925). A Catalogue of The Recent Sea Urchins (Echinoidea) in the Collection of The British Museum (Natural History). The British Museum, London, 250pp.

Denny, M. & B. Gaylord (1996). Why the urchin lost its spines: hydrodynamic forces and survivorship in three echinoids. The Journal of experimental biology 199(3): 717–729.

English, S., C.R. Wilkinson & V.J. Baker (1997). Survey Manual for Tropical Marine Resources. Australian Institute of Marine Science, Townsville, Australia.

Gallien, W.B. (1986). A comparison of hydrodynamic forces on two sympatric sea urchins: implications of morphology and habitat. MSc Thesis, University of Hawaii, Honolulu, HI, USA.

Hernández, J.C., S. Clemente, C. Sangil, & A. Brito (2008). The key role of the sea urchin Diadema aff. antillarum in controlling macroalgae assemblages throughout the Canary Islands (eastern subtropical Atlantic): an spatio-temporal approach. Marine Environmental Research 66(2): 259–270; http://dx.doi.org/10.1016/j.marenvres.2008.03.002

Himmelman, J.H. & C. Dutil (1991). Distribution, population structure and feeding of subtidal seastars in the northern Gulf of St. Lawrence. Marine Ecology Progress Series 76: 61–72; http://dx.doi.org/10.3354/meps076061

James, D.B. (1983). Research on Indian echinoderms-a review. Journal of the Marine Biological Association of India 25(1&2): 91–108.

James, D.B. (1987). Ecology of intertidal echinoderms of the Indian seas. Journal of the Marine Biological Association of India 24(1&2): 124–129.

Julka, J.M. & S. Das (1978). Studies on the Shallow‐Water Starfishes of the Andaman and Nicobar Islands. Mitteilungen aus dem Museum für Naturkunde in Berlin. Zoologisches Museum und Institut für Spezielle Zoologie (Berlin) 54(2): 345–351.

Lawrence, J.M. (2006). Edible Sea Urchins: Biology and Ecology. Developments in Aquaculture and Fisheries Sciences. Elsevier, Oxford UK, 380pp.

McCormack, G. (2007). Cook Islands Biodiversity Database. Version 2007.2. Cook Islands Natural Heritage Trust. Rarotonga. Available from: http://cookislands.bishopmuseum.org. Downloaded on 26 August 2014.

Mortensen. T. (1943). A Monograph of Echinoida. Vol. III, 3. Camarodonta. II. Echinoidae, Strongylocentrotidae, Parasaleniidae, Echinometridae. C. A. Reitzel, Copenhagen, 446pp.

Pearse, J.S. (2006). Ecological role of purple sea urchins. Science 314(5801): 940–941; http://dx.doi.org/10.1126/science.1131888

Santos, R. & P. Flammang (2008). Estimation of the attachment strength of the shingle sea urchin Colobocentrotus atratus, and comparison with three sympatric echinoids. Marine Biology 154: 37–49; http://dx.doi.org/10.1007/s00227-007-0895-6

Sastry, D.R.K. (1998). Some Echinoderms new to Mahatma Gandhi Marine National Park with two Records from India. Proceedings of Symposium on Island Ecosystem and Sustainable Development.: Andaman Science Association, Port Blair, 245pp.

Sastry, D.R.K. (1999). New records of Echinodermata from Andaman Island, Bay of Bengal. Journal of Andaman Science Association 15: 17–20.

Sastry, D.R.K. (2001). Echinodermata (other than Holothuroidea) from Ritchie’s Archipelago, Andaman Islands. Records of the Zoological Survey of India 99: 157–170.

Sastry, D.R.K. (2002). Echinodermata associated with coral reefs of Andaman and Nicobar Islands. Records of the Zoological Survey of India 100: 21–60.

Sastry, D.R.K. (2005). Echinodermata of Andaman and Nicobar Islands, Bay of Bengal: An annotated list. Records of the Zoological Survey of India 233: 1–207.

Sastry, D.R.K. (2007). Echinodermata of India: An annotated list. Records of the Zoological Survey of India 271: 1–387.

Zizka, M.D. (2012). Sea Urchins on the move: distribution change of Echinometra in Mo’orea French Polynesia. Berkeley Scientific Journal 15(1): 1–9.