An annotated species list of regular echinoids from Sri Lanka with notes on some rarely seen temnopleurids.

The first recorded regular echinoid species from Sri Lanka, "Salmacis virgulatus" (now known as S. virgulata L. Agassiz in L. Agassiz Desor, 1846), was listed by Agassiz Desor (1846). Knowledge of Sri Lankan regular echinoids continued to advance until the end of the 19th century. However, there is a gap in knowledge between the mid-20th and the beginning of the 21st centuries due to a lack of systematic studies, with the exception of two checklists published by the IUCN Red List in 2006 and 2012. In the present study, we compiled a species list combining published data and new data based on fieldwork between 2013 and 2015. Echinoids were sampled by snorkelling, diving, examination of fisheries bycatch, and collection of tests from beaches. The updated species list presented in this study includes 39 regular echinoids belonging to 28 genera, nine families, and five orders. Phyllacanthus imperialis (Lamarck, 1816) and Temnopleurus toreumaticus (Leske, 1778), which were not recorded during the last 90 years, were confirmed to still occur in Sri Lanka by the present study. We develop an updated species list of regular echinoids to form a basis for future systematic work. The study recommends further investigation to evaluate the status of deep-sea species and additional field work off the northern and eastern coasts of Sri Lanka.

Seasonal variations in the total lipid content and fatty acid composition of cultured and wild Crassostrea madrasensis in Sri Lanka.

The marketplace contains a choice of both cultured and wild oysters, often subtle differences in taste and characteristics are observed between wild and cultured oysters. Therefore, seasonal variations of total lipid and total fatty acid compositions were studied in both, wild and cultured populations of Crassostrea madrasensis in Gangewadiya in Kala-Oya estuary and in cultured populations in the Puttalam lagoon in Sri Lanka over a 13 month period. The fatty acid profile was analyzed using Gas Chromatography. The average lipid percentage was 1.28 ± 0.02% and there was no significant difference between cultured and wild oysters (p > 0.05). A total of 17 fatty acids was detected. Significant monthly variations were seen in all fatty acids, except docosapentaenoic acid (DPA/C22.5(n-3)) and docosahexaenoic acid C226(n-3). Significantly high concentrations (p < 0.05) of omega 3 fatty acids were recorded during October while significantly higher omega 6 concentrations were recorded during April (p > 0.05). Saturated fatty acids had the highest concentration followed by polyunsaturated fatty acids and monounsaturated fatty acids. Palmitic acid was the major saturated fatty acid and docosahexaenoic acid was the major polyunsaturated fatty acid. The ratio of total n-3 PUFA to total n-6 PUFA were 2.6, 2.9 and 3.0 in Gangewadiya wild, Gangewadiya cultured and Kandakuliya cultured oysters, respectively. Though there were no significant differences in omega 3 to omega 6 ratios in cultured and wild oysters in Gangewadiya, a significantly higher ratio was calculated for cultured oysters in Kandakuliya. Hence, a discriminant analysis indicated that in terms of the fatty acid composition, cultured C. madrasensis in Kandakuliya is distinct compared to wild and cultured populations from Gangewadiya. Since, both wild and cultured C. madrasensis shared the same waters in Gangewadiya, the lack of differences can be explained. However, in both sites and under wild and cultured conditions, fatty acid ratio confirms the importance of C. madrasensis as an ideal source of omega 3.

Taxonomy and distribution of irregular echinoids (Echinoidea: Irregularia) from Sri Lanka.

The earliest information on Sri Lankan echinoid species belonging to the Irregularia dates back to Alexander Agassiz (1872). However, the current knowledge of diversity and distribution of irregular echinoids from Sri Lanka (formerly Ceylon) remains sparse. In addition, there are no recent taxonomic studies or biodiversity surveys for irregular echinoids, and no illustrated field-guides or reference collections are available specifically for Sri Lanka. To address these gaps, left open for more than 100 years since the work of Clark (1915), this study was conducted as an island-wide systematic sampling survey. Over 200 echinoid specimens were collected from 24 localities in Sri Lankan coastal waters by snorkelling and SCUBA diving down to 33 m depth. The collected specimens were identified using existing keys and authenticated with specimens available at the Natural History Museum in Vienna, Austria. The present study records 22 irregular echinoid species belonging to 15 genera and nine families in four orders. Among the identified irregular echinoids, six species, Echinocyamus megapetalus H.L. Clark, 1914, Fibularia ovulum Lamarck, 1816, Fibulariella angulipora Mortensen, 1948, Echinodiscus cf. truncatus L. Agassiz, 1841, Peronella oblonga Mortensen, 1948 and Brissus cf. agassizii Döderlein, 1885, are new records for Sri Lanka. Four unidentified, possibly new species belonging to the genera Fibularia, Jacksonaster and Metalia are reported, but kept in open nomenclature until more material becomes available. At present, the diversity of irregular echinoids from Sri Lanka now stands at 37 species representing 11 families in four orders. A dichotomous key is presented for all Sri Lankan irregular echinoids.

A comparison of the larvivorous habits of exotic Poecilia reticulata and native Aplocheilus parvus.

BACKGROUND: The exotic fish Poecilia reticulata is promoted in the tropics as a biological control agent for aquatic pathogenic carriers, such as mosquitoes. Such control measures are often adopted blindly, ignoring the potential of native species and the adverse effects of introduced species. The present study was conducted to assess the diet composition of two species of fish, the native Aplocheilus parvus and exotic P. reticulata, and to assess the availability of food items in their natural environment in four types of aquatic systems. Diet composition was estimated using 24 h gut contents analysis, in a clay quarry pit and a perennial reservoir for A. parvus, and in a man-made canal and a second-order natural stream for P. reticulata. Food items in these environments were quantified by analyzing water samples collected every 2 h. RESULTS: The diet of A. parvus in the clay quarry pit and reservoir consisted of adult or larval stages of Insecta, Maxillopoda and Malacostraca. In both habitats, A. parvus selectively fed on insect parts and insect larvae. The diet of P. reticulata consisted of filamentous algae, diatoms and detritus. The diet of A. parvus showed active selection of insectivore food items against their low availability. In contrast, the diet of P. reticulata showed consumption of food items in accordance with their availability in the environment. The highest mean number of food items in the gut for A. parvus was recorded around mid-day in the clay quarry pit, but no peak feeding time was identified in the perennial reservoir. For P. reticulata, peak feeding was recorded around mid-day in both the habitats. CONCLUSION: Irrespective of the type of environment and rate of occurrence, A. parvus preferred insect and insect larvae, whereas P. reticulata consumed the most readily available food items. The active selection of insects by A. parvus suggests they may have value as a biological control agent.

A review of previous studies on the Sri Lankan echinoid fauna, with an updated species list.

A comprehensive review and analysis of the literature on echinoids from Sri Lankan waters were conducted to compile an annotated list that integrates the existing published data with original data from recent research. According to the published literature, 115 echinoid species and one subspecies have been reported from Sri Lanka to date. However, the current study revealed that only 66 echinoid species and one subspecies belonging to 20 families can be verified to occur in Sri Lankan waters. According to the present analysis, 49 species were excluded from the list due to uncertain records (16) or synonymy (33) with other taxa known from the region. Of the 66 species and one subspecies occurring in Sri Lankan waters, 11 were first described from type material collected from this region. Six of the type specimens are "regular" echinoids and five are Irregularia. Out of these 11, Araeosoma coriaceum indicum has been recorded only from and appears to be endemic to Sri Lankan waters. However, 34 species of Sri Lankan echinoids have not been recorded in the last 90 years. Echinoid species recorded from Sri Lankan waters represent 6.7% of the currently accepted species of extant echinoids and include representatives of 28% of the extant echinoid families. Forty-five percent (45%) of echinoids recorded from the Indian coast (113 species and subspecies) are present in Sri Lankan waters. The current study highlights the need for systematic revision of echinoid records in Sri Lanka through field surveys and reconciliation of discrepancies in the existing literature. Offshore sampling is also needed due to lack of recent information on local deep-sea echinoids.

Species composition and population dynamics of malaria vectors in three previously ignored aquatic systems in Sri Lanka.

BACKGROUND: In 2015 alone there were an estimated 214 million new cases of malaria across the globe and 438,000 deaths were reported. Although indigenous malaria has not been reported in Sri Lanka since 2012, to date 247 imported cases of malaria have been identified. Knowledge of the locations, behaviour and vectorial capacity of potential malarial vectors is therefore needed to prevent future outbreaks. Attention is now being focused on some previously ignored habitats. METHODS: Active and abandoned granite and clay quarry pits, located in wet and intermediate zones, and agro wells located in the dry zone of Sri Lanka were mapped and sampled for 1 year, as potential mosquito breeding sites. Species composition and spatio-temporal variation in both malarial and other mosquito larvae were recorded. RESULTS: A total of 18 species of mosquito larvae were identified. Other than Anopheles culicifacies, the primary malaria vector, five species of potential malaria vectors (Anopheles vagus, Anopheles varuna, Anopheles nigerrimus, Anopheles peditaeniatus and Anopheles barbirostris) were found in all three aquatic systems. Additionally, Anopheles annularis was found in granite quarries and Anopheles subpictus and Anopheles pallidus in both types of quarry, but only during the initial sampling. Apart from potential malaria vectors, mosquito larvae such as Anopheles jamesii, Culex tritaeniorhynchus, Culex infula and Culex malayi were found in all three habitats at least once during the sampling period. Apart from potential malaria vectors and other mosquito larvae common to all three aquatic systems, Culex gelidus, Culex mimulus and Culex pseudo vishnui were detected in agro wells. Culex gelidus was also detected in granite quarry pits. Culex mimulus, Culex lutzia and Culex fuscocephala were detected in clay quarry pits. Accordingly, a total of 14, 13 and 15 mosquito species were identified in agro wells, granite and clay quarry pits, respectively. CONCLUSIONS: Although zero occurrence of indigenous malaria has been achieved in Sri Lanka, the current study emphasizes the potential for future epidemics. The presence of native flora and fauna in abandoned granite and clay quarry pits and the need to extract drinking water from agro wells demand bio-sensitive control methods in these three aquatic systems.