Subject: Land planarians (Bipalium) of Sri Lanka [long]

I inquired after the identity of a terrestrial
flatworm which occurs in gardens, etc., in the lowlands of Sri Lanka
(e.g., Colombo, Kotte). What I have learned since then makes the
following corrections necessary: The front end of the worm is best
described as semicircular (anterior margin convex), and not 'horned'.
The width of the worm should have been (very approximately) about 0.5cm
(not 1cm). Terrestrial flatworms do not seem to be as unusual or rare
as I indicated, simply poorly studied relative to freshwater species.
Their systematic position is Phylum Platyhelminthes, Class Turbellaria,
Order Seriata, Suborder Tricladida, Infraorder Terricola. Within the
Terricola are grouped several families, of which the Geoplanidae and
Bipaliidae are mainly tropical, while the Rhynchodemidae seem to be
worldwide in distribution. I am fairly certain that the land planarian I
described belongs to the Bipaliidae and that it belongs to the genus
_Bipalium_. Several species of this genus are known from Sri Lanka, but I
have not been able to check what seems to be a complete list of world
species of Terricola (Ogren, Kwakatsu & Froehlich, 1993), so the list
below is certain to be very incomplete.

_Bipalium dendrophilum_ (Schmarda, 1859)
_Bipalium diana_ Humbert, 1861
_Bipalium proserpina_ Humbert, 1861
_Bipalium phoebe_ Humbert, 1861
_Bipalium ceres_ Moseley, 1874

The first report of a _Bipalium_ species from Sri Lanka seems to be the
following observation by Edgar Leopold Layard, a pioneer in the study
of Sri Lanks's birds and land snails: "I can speak by painful experience
of the land-leech, and I have seen another curious species at Pt. Pedro,
which is of a light brown colour above, white underneath; very broad and
thin, and has a peculiarly-shaped tail, half-moon shaped, in fact like a
grocer's cheese-knife; I have seen but two of these, and found them both
on the bark of trees, after some heavy rain." (Layard, 1853: 225). In
addition to incorrectly believing it to be a kind of land-leech, Layard
mistook the front end of the worm for its tail, as pointed out by Moseley
(1874), although he described its shape quite well. Schmarda (1859),
Humbert (1861), and Moseley (1874) described a total of five species of
this genus from Sri Lanka. Humbert's paper is said to have excellent
illustrations of the three species described by him, but I have not seen
it. _Bipalium kewense_ Moseley, 1878 is a very large species which is
believed to be indigenous to Indo-China and has been accidentally
introduced to many parts of the world; it is not known if this species
occurs in Sri Lanka. A good general account of Tricladida is given by Ball
& Reynoldson (198). Moseley's (1974) classic paper has a detailed account
of the anatomy of land planarians based primarily on the Sri Lankan
species _Bipalium diana_. Ogren (1995) reviews land planarian feeding
behaviour, including that of three species of _Bipalium_.

Moseley found that the land planarians he studied in Sri Lanka avoided
light and usually occurred in dark places such as under fallen leaves. His
specimens were collected at the Royal Botanic Gardens, Peradeniya, where
they were "especially abundant in Banana and Manilla-hemp plantations".
The best method of collecting the planarians was to place a large fresh
plantain-leaf on the grass near the plantation and after a few hours the
worms were found adhering to the under surface. Interestingly enough
Moseley found the common slug _Vaginula_ associated with the planarians.
All planarians are carnivores and terrestrial species like _Bipalium_ feed
on earthworms, etc. Species of this genus when moving carry the head
slightly raised and move it from side to side, evidently examining in this
manner anything in their way. They are able to produce a tough thread of
slime (mucus) from which they can suspend themselves. The ventral surface
has a median "ambulacral line" which is provided with cilia and is
apparantly the worms' means of locomotion. The longest specimen of
_Bipalium diana_ collected by Moseley was 5 1/2 inches long and 1/4 inch
in breadth.


Ball, I. R. & Reynoldson, R. B. 1981. British Planarians.
    Platyhelminthes: Tricladida. D. M. Kermack & R. S. K. Barnes (eds.),
    Synopses of the British Fauna (new series), 19. Cambridge University
    Press, Cambridge.
Humbert, A. & Claparede, E. 1861. Description de quelques especes
    nouvelles de Planaires de Ceylon, par M. Alois Humbert, suivie
    d'observations anatomiques sur le genre _Bipalium_, par M. Edouard
    Claparede. Memoires de la Societe de Physique et d'Histoire Naturelle
    de Geneve, 16: 293-? [NOT SEEN]
Layard, E. L. 1853. Rambles in Ceylon. Annals and Magazine of Natural
    History (ser. 2), 11(63): 224-236.
Moseley, H. N. 1874. On the anatomy and histology of the land-planarians
    of Ceylon, with some account of their habits, and a description of
    two new species, and with notes on the anatomy of some European
    aquatic species. Philosophical Transactions of the Royal Society of
    London, 164(1): 105-171, plts. 10-15.
Moseley, H. N. 1878. Description of a new species of land-planarian from
    the hothouses of Kew Gardens. Annals and Magazine of Natural History
    (series 5), 1(3): 237-239.
Ogren, R. E. 1995. Predation behaviour of land planarians. Hydrobiologia,
    305(1-3): 105-111.
Ogren, R. E., Kawakatsu, M. & Froehlich, E. M. 1993. Additions and
    corrections of the previous land planarian indices of the world
    (Turbellaria, Tricladida, Terricola). Addendum 1. Combined taxonomic
    index: Bipaliidae; Rhynchodemidae (Rhynchodeminae; Microplaninae);
    Geoplanidae (Geoplaninae; Caenoplaninae; Pelmatoplaninae)-exclusive
    of Winsor's second 1991 paper. Bulletin of Fuji Women's College 31:
    33-60. [NOT SEEN]
Schmarda, L. K. 1859. Neue wirbellose Thiere beobachtet und gesammelt
    auf einer Reise um die Erde 1853 bis 1857. Bd. 1. Neue turbellarien,
    rotatorien und anneliden. W. Engelman, Leipzig. [NOT SEEN]


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