Description of a new
coral species Ctenactis triangularis (Scleractinia: Fungiidae) from
Andaman Islands, India
Tamal Mondal1 & C. Raghunathan 2
1,2 Zoological Survey of India,
Andaman and Nicobar Regional Centre, Port Blair, Andaman and Nicobar Islands
744102, India
1 t_genetics @yahoo.com (corresponding author), 2 raghuksc@rediffmail.com
Abstract: A new species of scleractinian coral Ctenactis triangularissp. nov. inthe family Fungiidae has been described from the
Andaman and Nicobar Islands. This
species has a triangular arm shaped corallum with the
mouth extending along all three arms. Septal dentition is long, cylindrical, equally
sized and closely arranged. Numerous pits on the costae and costal spines are spinulose. Ctenactis triangularis sp. nov. has an affinity with Ctenactis echinata (Pallas, 1766), Ctenactis crassa (Dana, 1846) and Ctenactis albitentaculata (Hoeksema,
1989), thus the morphological features have been compared with these three
species and discussed.
Keywords: Andaman & Nicobar Islands, coral, Ctenactis,Fungiidae.
doi: http://dx.doi.org/10.11609/JoTT.o3194.4653-9 | ZooBank:urn:lsid:zoobank.org:pub:12A21252-A751-46E5-BCF9-394ACB37012D
Editor: John Veron,
Coral Reef Foundation, Townsville, Australia Dateof publication: 26 August 2013 (online & print)
Manuscript details: Ms # o3194
| Received 10 May 2012 | Final received 17 July 2013 | Finally accepted 19 July
2013
Citation: Mondal,
T. & C. Raghunathan (2013). Description
of a new coral species Ctenactis triangularis (Scleractinia: Fungiidae) from Andaman Islands, India. Journal
of Threatened Taxa 5(12): 4653–4659; http://dx.doi.org/10.11609/JoTT.o3194.4653-9
Copyright: © Tamal Mondal & C. Raghunathan2013. Creative Commons Attribution 3.0 UnportedLicense. 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: The Ministry of Environment
and Forests, Government of India.
Competing Interest: Authors
declare no competing interest.
Acknowledgements: The
Authors are grateful to the Ministry of Environment and Forests, Government of
India for financial support and facilities provided. Authors are thankful to
the Director of this institution for his encouragement, support and extended
facilities.
For images, table -- click here
Mushroom corals (Family Fungiidae) are one of the most conspicuous groups
restricted to shallow-water habitats of coastal areas, islands and banks in the
tropical Indo-Pacific reefs. This
family is one of the very few in which species can be traced back to
pre-Linnaean literature (Tournefort 1706; Rumphius 1750). The Fungiidae includes both colonial forms and
the mushroom-shaped, monostomatous (presence of
single mouth), free living corals of the genera Cycloseris, Diaseris, Fungia, Ctenactis and Heliofungia. Although these genera are fundamentally monostomatus,
there is an incipient tendency to develop several mouths among the several species
under above said genera (Veron & Pichon 1980). All colonial fungiids are derived from the
solitary genus Cycloseris or else from four of
the five subgenera of Fungia, and have
inherited the septo-costal structures of their
predecessors (Wells 1966).
In the tropical Indo-Pacific
region, 41 species of fungiid corals have been found
(Hoeksema 1989) out of a total of 56 species of
mushroom corals recorded throughout the world (Veron2000). Venkataramanet al. (2003) recorded 22 species of mushroom corals in Indian waters. However, Ramakrishna et al. (2010)
recorded 44 species of mushroom corals from Andaman & Nicobar Islands.
Revisionary studies on the
family Fungidae revealed three species of Ctenactis—the occasionally polystomatous C. echinata (Pallas, 1766), the
consistently polystomatous C. crassa (= Herpetoglossasimplex) (Dana, 1846), and the almost consistently monostomatous C. albitentaculata (Hoeksema1989; Veron 2000). All three species constitute a genus
which can easily be separated from Fungia by
a combination of characters: (i) the coralla are more elongate and become much larger and
heavier; (ii) the septal and costal ornamentations
are coarser and more spinose; (iii) there exists a
clear tendency from monostomatism to polystomatism, in which C. albitentaculata and C. crassa are the
extremes and C. echinata an
intermediate form (Hoeksema 1989). The genus Ctenactis Verrill, 1864 is characterized by an elongate corallum with coarse, elongated septaldentations at least 1.5mm apart and composed of numerous, strongly diverging trabeculae. Costae are unequal, with strong and arborescentspines (Veron & Pichon1980). Only three species in this
genus Ctenactis have been recorded globally
all of which have been found in the Andaman & Nicobar Islands (Ramakrishna
et al. 2010).
The present specimen has
characteristic differences from the previously reported three species of genus Ctenactis and hence it is described as a new speciesCtenactis triangularis.
Material and Methods
The coral specimen was
collected in Rutland Island (Fig. 1), South Andaman by snorkeling as well as skindiving. Morphological measurements were made with Vernier Caliper. Characteristic features of the specimen were examined
using the digital stereozoom microscope, model Leica M205A. Two other specimens were observed at the study area. Taxonomic characters of the specimen
were studied by comparing the three related species—Ctenactis echinata (Pallas, 1766) and Ctetactis crassa (Dana, 1846) and Ctenacatis albitentaculata (Hoeksema,
1989)—in consultation with the keys prepared by Veron& Pichon (1980) and Veron(2000).
Systematic Position
Order ScleractiniaBourne, 1900
Suborder Fungiina Verrill, 1856
Superfamily Fungiicae Dana, 1846
Family FungiidaeDana, 1846
Genus Ctenactis Verrill,
1864
Species Ctenactis triangularis sp. nov.
(Image 1)
urn:lsid:zoobank.org:act:C3FF1598-96AD-4D94-A644-D7EEFD473DEA
Material Examined
Holotype: ZSI/ANRC-4899, 04.vii.2008, one
example collected (Image 1) at a depth of 4m in reef area of Surumai Dikri (11025.504’N
& 92040.301’E), located at Rutland Island, South Andaman. Length of the three corallumfrom the centre is 12.1cm, 10.2cm and 9.6cm. Width is
9.3cm, 8.4cm and 7.8cm. Height of the coralla is
3.9cm. Collected by C. Raghunathan and party; holotypedeposited in the National Zoological Collections of Zoological Survey of India,
Port Blair.
Paratype: One specimen was observed at
North Bay (11042.068’N & 92045.116’E) South Andaman
during December 2008 and another specimen was observed at Elephant Beach (12000.582’N
& 92056.838’E), Havelock Island, Ritchie’s Archipelago, Andamans, on 06 July 2010.
Diagnostic characters: Triangular
arm like corallum, oval-elongate mushroom corals, monostomatous (usually with a single, large mouth). The
mouth is divisible in three extensions and extends in each arm of the coralla. Oral surface is humped and convex around the
mouth. Septa straight or sinuous, the terminal ends of the corallaare regularly rounded. The septa are thick and equal in size with large, strong
dentition on the margin. The septal teeth are echinulate in structure. Costae are well developed with
large, cylindrical spines. The spinulose are present
on the top and side walls of the spine. Pits are present throughout the costae.
Comparison with the other Ctenactis species: The new species (Images 2A, 3A) was compared with the existing
specimens of Ctenactis echinata(Pallas, 1766) (Images 2B, 3B), Ctenactis crassa (Dana, 1846) (Images 2C, 3C) and Ctenacits albitentaculata(Hoeksema, 1989) (Images 2D, 3D) in order to
distinguish the new species from closely related species with morphological
characters. The comparative data is given in Table 1.
Etymology
The species has been named
after the triangle-shaped arm like coralla, which
gives a unique morphological character to distinguish it from other related
species.
Discussion
A newly described coral
species Ctenactis triangularissp. nov. isdescribed from the Andaman and Nicobar Islands. Although this species’ close affinity
with a few morphological characters of other closely related species such as Ctenactis echinataand Ctenactis crassa,
it distinctly differs from having a triangular flat-shaped corallum,
divisible mouth fossa, spinulose costal spines and
cylindrical septal teeth. It is pertinent to note that only three
species are reported under genus Ctenactisfrom world waters as well as the Andaman and Nicobar Islands. Morphological plasticity can be observed
among these species, but this is not morphological differentiation of
previously described species as all the characters of key components such as
septa, costae, mouth and their arrangement is totally different from previously
recorded species. The analytical
result of all the characters of the described species is definitely a new
description. The presently
described species from these Islands is a new addition to the genus Ctenactis. Coral reefs are very important marine
organisms, and play a vital role in enriching marine biodiversity. Threats, which can be categorized as
natural and anthropogenic, to the reef biodiversity, have been encountered for
a long time. As survival of the
coral reef environment means a lot for the sustainable development of a whole lot
of marine biota, conservation action plans have been taken for consideration
globally, to give them protection against anthropogenic degradation. Scleractiniancorals were included under CITES Appendix II. Not only that, scleractinianswere included as Schedule-I species under Indian Wildlife (Protection) Act,
1972 to make sure that proper protection as well conservatory measures are
ensured for the future generation.
References
Dana, J.D. (1846). Zoophytes. U.S. Exploring Exped. 1838–1842.
Hoeksema, B.W. (1989). Taxonomy,
phylogeny and biogeography of mushroom corals (Scleractinia:Fungiidae). Zoologische Verhandelingen Leiden 254: 1–295.
Pallas, P.S. (1766). Elenchus Zoophytorum. Van Cleef, Hagae-Comitum, 1-451.
Ramakrishna,
C. Raghunathan, T. Mondal& Sivaperuman (2010). Fungiids of Andaman and Nicobar
Islands. Guide to Fungiids of Andaman &
Nicobar Islands. Published by the Director, Zoological Survey of India, Kolkata,
101pp
Rumphius, G.E. (1750). Her Amboinsche Kruid-Boek. Herbarium AmboinscheAmsterdam, Pt 6.
Tournefort, J.P. de (1706). Observationssur les plantes qui naissent dans le fond de la mer. Mémoires de l’Académie royale des science (Paris) Annee1700.
Venkataraman, C., C. Satyanarayan,
J.R.B. Alfred & J. Wolstenholme (2003). Handbook
on Hard Corals of India. Published by the Director, Zoological Survey of India, Kolkata, 266pp.
Veron, J.E.N. & M. Pichon (1980). Scleractinia of
Eastern Australia - Part III. Australian Institute of
Marine Science. Townsville, 433p.
Veron, J.E.N. (2000). Corals
of the World - Volume 2. Australian Institute of Marine Science. Townsville,
429pp.
Verrill, A.E. (1864). List of
the polyps and corals sent by the Museum of Comparative Zoology to other
institutions in exchange, with annotations. Bulletin
of the Museum of Comparative Zoology, Harvard College. Cambridg 1: 29-60.
Wells, J.W. (1966). Evolutionary development in
the scleractinian family Fungiidae,
pp. 223–246. In: Rees, W.J. (ed.). The Cnidariaand Their Evolution. Symposium of the Zoological Society, Academic Press, London 16: pl. 1.