Page 7 - IJMS-2015v5n2

International Journal of Marine Science 2015, Vol.5, No.3, 1-7
http://ijms.biopublisher.ca
4
Figure 4 (a) Diagram of dorsal cirri bearing lateral pinnate gills
(40 X), (b) Microphotograph of 18th left foot of Dendronereis
aestuarina bearing lateral pinnate gills (front view)
Dorsal cirri bearing the lateral pinnate gills, which
commence at the 14th-15th foot. In the males, the
dorsal cirrus of the heteronereized segments bear a
series of wart-like protuberances on the ventral surface
while in the females examined these cirri were smooth.
COLOUR: Throughout their life the body is reddish
brown, the colour being probably due to the blood,
and the gills and dorsal vessels are bright red. The
body in front of the gills is much darker, and appears
to be coloured with reddish brown pigment.
DISTRIBUTION: D. aestuarina is widely distributed
along the Indian coast. It has been reported from both
east coast [Chilka Lake(Southern 1921,Kaushal and
Binford 1999), Kakinada Bay(Vijayakumar et al.
1991), mangroves of Tamil Nadu coast(Rouse and
Pleijel 2001)] & west coast of Indian [Cochin estuary
(Sarala Devi et al. 1991b), Periyar River (present
study), Nethravathi estuary(Jepsen et al. 1997),
Talapady River(Dorresteijn and Westheide 1999),
Ratnagiri coast(Westheide 2004), Mandovi – Zuari
estuary(Nimi 2003)].
TYPE LOCALITY: Brackish water environment of
Chilka Lake
REMARKS: There were four species described under
the genus Dendronereis. They are Dendronereis
aestuarina Southern, 1921; Dendronereis arborifera
Peters, 1854; Dendronereis dayi Misra (Endemic to
West Bengal, India), 1999 and Dendronereis
pinnaticirris Grube, 1878.
D. aestuarina was described by Southern (1921)from
nineteen specimens of this species, collected from
brackish water on November 27th, 1911, by Mr. S. G.
Platts in the Sunderbans, a district in the Gangetic
Delta and sent by him to the Indian Museum. The type
specimen is 160 mm long, and consists of 160
setigerous segments. It is a female full of immature
ova(Southern 1921, Gottfried Pillai 1965, Sunil
Kumar 2003,Chan 2009). In the lower reaches of
Periyar River such as Kodungallure-Azhikode estuary
and Cochin estuary, the dominant polychaetes were
Dendronereis aestuarina, Dendronereides zululandica,
Prionospio polybranchiata and Heteromastus
filiformis (Pillai 1977, Sarala Devi and Venugopal
1989,Sarala Devi et al. 1991b,Sarala Devi et al. 1992,
Sheeba 2000,Pillai 2001, Feebarani 2009).
Researches on the polychaetes in this region are
mainly concentrated on taxonomy and distribution.
3 Discussion
Nereididae is a group of polychaete worms that is
relatively well known for having been first mentioned
in pre-Linnaean writing. This family is one of the
most diverse polychaete families in the world and the
most diverse species in the Indian Ocean region. In the
present study, we report the occurrence of red
coloured mass reproductive swarming of Nereididae
polychaete D. aestuarina from the purely freshwater
environment of Periyar River in the south west
coast of India. There were no previous reports on
swarming phenomena of this species except on
species description reports of D. aestuarina from
brackish water environment of Chilka Lake by
Southern (1921).
Environmental cues control or synchronize the
breeding of many marine invertebrates. Of these,
photoperiod, temperature, endogenous and lunar
timing have been shown to moderate reproduction
either individually or in combination. In addition, they