Abstract The present study determined the distribution of freshwater gastropods in relation to several environmental variables, in two tributaries of the Mahaweli River, Hulu Ganga and Ma Oya in the Central Province of Sri Lanka. Pearson’s Correlation and a multivariate statistical technique, Canonical Correspondence Analyses (CCA) were used to explore the environmental variables responsible for the species composition. In total eight species of gastropods were recorded. The most influential factors for the four species recorded in Hulu Ganga were dissolved oxygen (DO), total dissolved solids, conductivity and elevation, whereas in Ma Oya they were pH, conductivity, DO and temperature. The results of CCA show that measured environmental variables explained 95.76% of the variation in gastropod abundance in Hulu Ganga, but only 60.63% was explained in Ma Oya. Hence, there may be other unmeasured environmental factor(s) that influence the diversity and distribution of gastropods in Ma Oya.
Abstract We here describe a new rupicolous day gecko species nested within the C. gracilis clade from Madurai, Tamil Nadu, India. The new species differs with a combination of morphological characters and molecular phylogenetics, from other closely related congeners. The sequence divergence of the new species in comparison with the congeners from the gracilis clade is 6.1–15.2% for the ND2 gene. The new species can also be differentiated from the congeners based on the following combination of morphological characters: conical and spine-like tubercles absent on flanks; adult SVL less than 35.0 mm; two precloacal pores; precloacal pores separated medially by two poreless scales; four femoral pores; number of mid-ventral scales 110–120; and a small black colour spot on the occiput.
Abstract Draposa is a relatively newly described wolf spider genus numbering 11 species, out of which eight have been reported from India. A new Draposa species from Kerala, Western Ghats, India, is described, photographed and illustrated. The male palp of the new species is similar to that of D. lyrivulva distributed in Pakistan, India and Sri Lanka, but it differs by having the following combination of characters: shorter tegular apophysis with a narrow and linear tip, prominent sub-apical protrusion, and embolus parallel to tegular apophysis.
Key words : Arachnida, distribution, Kerala, Pardosa, South Asia, taxonomy
Submitted date: 28 March 2022 Accepted date: 16 November 2022 Published date: 22 November 2022 Pp. 119–121.
Seaweed (macroalgae) diversity on the Dikwella coast, Southern Sri Lanka
M.L.I. De Silva*, M.S. Gunasinghe, P.H. Liyanagedara, M.A.S. Ranjula, H.M.S.M Herath, N. I. Bamunuarachchi & W.A.A.D.L Wickramasinghe *Corresponding author. E-mail: ninelawlis1@gmail.com
Seaweeds are photosynthetic and macroscopic eukaryotic organisms found in marine and brackish water environments. They are one of the major primary producers in marine ecosystems. They are also important in maintaining coastal biodiversity by interacting with other organisms. In addition to their biological and ecological importance, seaweeds are economically significant. Data from the Food and Agriculture Organization (FAO) shows that a total of 35 million tonnes of seaweed were produced through cultivation in 2019 and 97% of this was from East Asia. China was ranked as the top producer. In contrast to all the positives, there are a few negative impacts of seaweeds; including biofouling, habitat invasion, and unwanted beach drift.
Submitted date: 30 January 2022 Accepted date: 30 October 2022 Published date: 22 November 2022 Pp. 114–118, Pls. 35–36.
On the critically endangered red teruntum mangrove (Lumnitzera littorea)
S. Madhushanka*, K.B. Ranawana & M. Prassanna *Corresponding author. E-mail: shashimadhushanka2@gmail.com
Mangroves are ecologically important forest communities along tropical and subtropical coasts with 70 woody species belonging to about 30 genera in 20 families. Lumnitzera littorea (Jack) Voigt of the Family Combretaceae is a critically endangered true mangrove species indigenous to Sri Lanka. This species is distributed widely on the east coast of Africa, northern Australia, Polynesia, and tropical Asian countries. It is only known from a few locations in Sri Lanka. Therefore, in Sri Lanka L. littorea has been identified as a critically endangered (CR) species in 2007, 2012, and 2020 National Red Lists.