Chelatrematidae n. fam., a new family of digenetic trematodes from the South Western Ghats, India, erected on the basis of morphological and molecular studies.

On the basis of the morphological characterization of Chelatrema neilgherriensis Manjula & Janardanan, 2006 recovered from the freshwater fish Barilius gatensis (Valenciennes, 1844) in the Wayanad region of the Western Ghats, the diagnostic features of the genus Chelatrema Gupta & Kumari, 1973 have been modified. Based on the phylogenetic analysis of C. neilgherriensis and comparative morphology studies relative to members of other families of Gorgoderoidea Looss, 1901, this genus is placed in a new family Chelatrematidae n. fam. The studies revealed the molecular and morphological closeness of Chelatrema with Paracreptatrematina limi Amin & Myer, 1982, and the latter is transferred to this new family. Hence the new family Chelatrematidae n. fam. comprises the genera Chelatrema and Paracreptatrematina.

Distribution of different species of metacercariae in two freshwater fishes: Haludaria fasciata (Teleostei: Cyprinidae) and Pseudosphromenus cupanus (Teleostei: Osphromenidae).

Information on the distribution and abundance patterns of trematodes are essential to reveal the ecology of host-parasite interactions. The Western Ghats of India, a biodiversity hotspot, is rich in freshwater fish diversity and endemism. Though there are several studies on various other aspects of fish ecology, studies on their parasitic fauna is meager. The objective of the present study is to explore the distribution and infection patterns of metacercariae of five species of trematodes in the freshwater fishes, Haludaria fasciata and Pseudosphromenus cupanus. The infection parameters were analyzed for each host and CART model was applied to analyze the environmental factors affecting parasite distribution patterns. All species of metacercariae showed an over-dispersed aggregate distributions. The classification tree models indicated that among the environmental factors considered, differences in host locality was the most influential factor in both fishes, followed at a greater distance by the factor seasonality. The parasite communities exhibited temporal and spatial differences in the infection pattern in response to seasonal and locational variations.

The costs of migration: Injuries in migratory waterbirds along the west coast of India.

The long distant, transcontinental migration of shorebirds entails many well identified costs in terms of time, energy, and direct mortality risk. Injuries from debris or from human structures and activities were observed as the major reasons for the direct mortality of shorebirds during migration worldwide. We recorded injured birds in major coastal wetlands of Kerala, for a period of 15 years from 2005 to 2019. The injured birds were observed in 9 different sites in various districts of Kerala. The highest instances of injuries were observed in Kadalundi-Vallikunnu Community Reserve, the major wintering and stop over site of migrant shorebirds in the west coast of India. During the study period, fifty-eight individuals of shorebirds belonging to four families were found to be injured. The highest proportion of injuries was recorded among the families Scolopacidae and Charadriidae comprising long distance migrant shorebird species and the lowest among Laridae and Ardeidae. We recommend that environmental authorities pay special attention to minimize anthropogenic debris along the flyways used by migratory birds thereby reducing the risk of injuries to some of these species. Proactive measures such as removal of discarded fishing gear or plastic debris from wintering areas as well as stopover areas could greatly reduce injuries in migratory birds arising from anthropogenic sources.

Tetracotyle wayanadensis (Trematoda: Digenea) metacercaria - A potential parasitic castrator of the freshwater fish Aplocheilus lineatus (Valenciennes, 1846): A histopathological and temporal variation study in the South Western Ghats, India.

Parasitic castration is a phenomenon where the parasite blocks or reduces the host reproductive output. This study explored the impact of Tetracotyle wayanadensis infection on the reproductive performance of the freshwater fish Aplocheilus lineatus. Heavily infected A. lineatus showed slow and sluggish movements with reduced food intake and feeding activities. Histopathological observations of the ovary revealed severe necrosis and degeneration of previtellogenic and vitellogenic oocytes and follicular atresia. The oogonial nests were absent; chromatin nucleolar oocytes irregularly shaped and vacuolated. Perinucleolar oocytes have a vacuolated appearance with the hypertrophied highly columnar follicular cells invading them. Vitellogenic oocytes had a shrunken appearance with folded zona radiata; yolk globules broken down into smaller granules together with vacuolar degeneration of the ooplasm. The hypertrophied highly columnar follicular cells invaded the early vitellogenic oocytes to phagocytize the degenerating material. Zona radiata was found broken and liquefaction of yolk globules was evident with advancement in follicular atresia. Seasonal variation of parasitic infection has also been studied. Metacercaria infecting the vital organs showed seasonal variation with the highest values for prevalence and abundance during monsoon and mean intensity during winter. The lowest values for these descriptors were documented during the post-monsoon period.

Studies on the life cycle of Pleurogenoides wayanadensis Shinad & Prasadan, 2018 (Digenea: Pleurogenidae) from the Western Ghats, India.

The life cycle of Pleurogenoides wayanadensis Shinad & Prasadan, 2018, infecting the frogs Hoplobatrachus tigerinus and Euphlyctis cyanophlyctis, is elucidated in this study. All the life cycle stages from egg to egg-producing adults were elucidated under natural conditions and successfully established in the laboratory. The life cycle took about 58 to 65 days for completion. Miracidia were released by teasing the eggs with fine needles. Sporocysts were found in the freshwater snail, Bithynia (Digoniostoma) pulchella, collected from paddy fields at Payode, Western Ghats, Wayanad region, in the months of October and November 2019. Cercariae were of the virgulate xiphidiocercous type. Metacercariae were recovered from the eyes of the damselfly naiads of the species Ischnura sp. and Copera sp., and the thorax and abdomen of the dragonfly naiads, Orthetrum sp. The metacercariae showed progenetic development. The growth and development of the metacercariae in the naiads that were exposed to cercariae, and development of the trematode in frogs that were force-fed with encysted metacercariae, have been studied at regular intervals. The prepatent period is 14-19 days. The present life cycle study of a Pleurogenoides spp. forms the seventh report from the world, fourth report from India and the third from Kerala.

Phylogenetic Position of Pleurogenoides Species (Plagiorchiida: Pleurogenidae) from the Duodenum of Indian Skipper Frog, Euphlyctis Cyanophlyctis (Amphibia: Dicroglossidae) Inhabiting the Western Ghats, India.

Two species of digenetic trematodes of the genus Pleurogenoides viz., P. cyanophlycti Shinad & Prasadan (2018a) and P. euphlycti Shinad & Prasadan (2018b) have been described from India. Information regarding the molecular data of various species of the genus Pleurogenoides Travassos, 1921 is virtually lacking. This study addresses the application of molecular markers to validate the phylogenetic position of P. cyanophlycti and P. euphlycti. In the present study, two species P. cyanophlycti and P. euphlycti were collected between January 2016 to October 2017, infecting the freshwater frogs inhabiting the Western Ghats, India. In the present study, the two species were identifi ed morphologically and by PCR amplification of the 28S ribosomal RNA gene. Phylogenetic tree results clearly demonstrate that both P. cyanophlycti and P. euphlycti belongs to the family Pleurogenidae Looss, 1899. Based on these results, we presented and discussed the phylogenetic relationships of P. cyanophlycti and P. euphlycti within family Pleurogenidae from India. Phylogenetic analyses showed that P. cyanophlycti and P. euphlycti cluster according to their vertebrate host and revealed an important congruence between the phylogenetic trees of Pleurogenoides and of their vertebrate hosts. P. cyanophlycti and P. euphlycti clearly constitute a separate, sister branch with other species of the genera, Pleurogenoides, Pleurogenes (=Candidotrema), Prosotocus and Brandesia. The present study firstly provides important information about the molecular study and phylogenetic analysis of P. cyanophlycti and P. euphlycti. This study will also serve as a baseline for Pleurogenoides species identifi cation for further studies.

A parapleurolophocercous cercaria and a furcocercous cercaria from the freshwater gastropods of the Western Ghats.

Two cercariae were recorded from freshwater snails, one each from Digoniostoma pulchella and Indoplanorbis exustus and named Cercaria sp. III Western Ghats n.sp. and Cercaria sp. IV Western Ghats n.sp. respectively. Cercaria sp. III Western Ghats n.sp. is distome, ocellate and pharyngeate with peculiar spines on the tail, belongs to the Parapleurolophocerca group. This cercaria has 10 pairs of penetration glands in two groups; thick walled large excretory bladder and 10 pairs of flame cells including a pair arising from the caudal excretory canal. Cercaria sp. III Western Ghats n.sp develops inside the sausage shaped redia. Developed cercariae were found outside the rediae, in the host tissue. The furcocercous cercaria, Cercaria sp. IV Western Ghats n.sp is elongate, non ocellate, pharyngeate and longifurcocercous with three crowns of spines beside mouth, three pairs of penetration glands, small excretory bladder and twenty-two flame cells including four flame cells in the tail stem. Asexual multiplication of the organism occurs inside the sporocyst in the hepatopancreas of I. exustus. The present paper reports two new cercariae with their intra-molluscan stages recovered from the snails of the Wayanad region of the Western Ghats, and their morphological and morphometric comparison with the related species to determine their systematic positions.

Two new species of furcocercous cercariae from freshwater gastropods of Western Ghats.

Two new furcocercous cercariae, Cercaria sp. I Western Ghats n. sp. and Cercaria sp. II Western Ghats n. sp. were found infecting the freshwater snails Indoplanorbis exustus and Thiara tuberculata respectively of the Wayanad region of the Western Ghats. Cercaria sp. I Western Ghats n. sp., a distome, apharyngeate, non-ocellate and spinose cercaria having three pairs of penetration glands, kidney- shaped small caeca and 20 pairs of flame cells including a pair in the furcae was recovered from I. exustus and Cercaria sp. II Western Ghats n. sp., a non-ocellate, pharyngeate, longifurcate furcocercous cercaria with two pairs of irregularly bordered penetration glands, septate caeca and 21 pairs of flame cells including three pairs in the furcae, from T. tuberculata. Sporocysts of Cercaria sp. I Western Ghats n. sp. were sausage-shaped while that of Cercaria sp. II Western Ghats n. sp. were thread-like and both of them developed in the hepatopancreas of their hosts. This paper describes the two new cercariae with their intramolluscan stages and compares them with related species to establish their systematic positions.

Description of Tetracotyle wayanadensis n. sp. (Digenea: Strigeidae) metacercaria infecting six species of freshwater fishes from Western Ghats, India.

Tetracotyle wayanadensis n. sp. (Digenea, Strigeidae) infecting different organs of six species of freshwater fishes, Haludaria fasciata (eye, buccal cavity), Amblypharyngodon melettinus (eye, buccal cavity), Aplochelus lineatus (operculum, heart, mesenteries), Pethia conchonius (brain), Parambassis thomassi (muscles, mesenteries) and Lepidocephalus thermali (mesenteries) collected from water bodies in the Wayanad region of the Western Ghats is described and illustrated. Tetracotyle wayanadensis n. sp. is new to the genus and is separated from its congeners on the basis of differences in morphology and morphometry. The present paper also describes the prevalence, intensity, mean abundance and sites of infection of the parasite in each host. The prevalence of infection of T. wayanadensis n. sp. in Haludaria fasciata is 7.5%, intensity of infection is 2.66 and mean abundance is 0.2; in Amblypharyngodon melettinus 10%, 6 and 0.6; in Aplochelus lineatus 12.2%, 6.2 and 0.76; in Pethia conchonius 7.14%, 5 and 0.36; in Parambassis thomassi 100%, 2 and 2; in Lepidocephalus thermali 10%, 2 and 0.2 respectively.

Description of Pleurogenoides cyanophlycti n. sp. (Digenea: Pleurogenidae) infecting Euphlyctis cyanophlyctis from the Western Ghats, India.

Pleurogenoides cyanophlycti n. sp. (Digenea, Pleurogenidae) from the intestine of the water skipper, Euphlyctis cyanophlyctis (Anura, Dicroglossidae), inhabiting the Western Ghats, India is described and illustrated. Pleurogenoides cyanophlycti n. sp. is new to the genus and is separated from its congeners on the basis of differences in morphology and morphometry. It is named after the host, E. cyanophlyctis.

Two new species of Pleurogenoides (Luhe, 1901) Travassos, 1921 (Digenea: Pleurogenidae) infecting two species of frogs of the Western Ghats, India.

Two new species of digenetic trematodes of the genus Pleurogenoides infecting the freshwater frogs, Euphlyctis cyanophlyctis and Hoplobatrachus tigerinus inhabiting the Western Ghats, India are described and illustrated. Pleurogenoides euphlycti n. sp. and P. wayanadensis n. sp. are separated from their congeners on the basis of differences in the morphology and morphometry. The prevalence of infection of P. euphlycti n. sp. in E. cyanophlyctis is 8.99% and in H. tigerinus 12.5% and the intensity is 6.5 and 7.0 respectively. Prevelance of P. wayanadensis n. sp. in E. cyanophlyctis is 4.49% and in H. tigerinus 6.25% and the intensity is 11.25 and 6 respectively. Since trematode parasites have complex life cycles, with multiple hosts that follow trophic level transfer, the parasite larvae may serve as reliable indicators of species diversity in an ecosystem.

Studies on the life-cycle of Pleurogenoides ovatus Rao, 1977 (Trematoda: Pleurogenetinae).

The life-cycle of Pleurogenoides ovatus Rao, 1977, infecting the frogs, Rana tigrina and R. cyanophlyctis has been elucidated. All the life-cycle stages from egg to egg-producing adults were successfully established in the laboratory. The life-cycle took about 80 days for completion. Cercariae were found in the freshwater snail. Digoniostoma pulchella, collected from paddy fields at Chelembra, Malappuram district of Kerala, during the monsoon months. Cercariae are of the virgulate xiphidiocercous type. Metacercariae occurred in the connective tissues, hepatopancreas and musculature of the freshwater crab, Paratelphusa hydrodromous. The growth and development of the metacercariae in P. hydrodromous have been studied in detail. Frogs became infected when they fed on infected crabs. The prepatent period is 10 days.