The morphology and genetic characterization of Iheringascaris goai n. sp. (Nematoda: Raphidascarididae) from the intestine of the silver whiting and spotted catfish off the central west coast of India

Redescription of alien nematode, Rostellascaris spinicaudatum (Malhotra and Anas, 2001) of evolutionary significance with revised key to the family Raphidascarididae Hartwich 1954

The redescription of Rostellascaris spinicaudatum has brought to focus Scanning Electron microscopic evidence of evolutionary consequence. The intestinal caeca, ventriculus and ventricular appendix of family Anisakidae; ventriculus and ventricular appendix of family Raphidascaridae; and along with it, post-cloacal collarette of family Physalopteridae in worms recovered from coral-reef associated fish hosts at 'Grande' island, evidently confirmed that the characters of as many as three families were encountered in R. spinicaudatum. The selective adaptation of these specific characters exhibited significant evolutionary trend, and indeed these could radiate connecting link features of Raphidascarididae. Additionally, an inversely bifurcated interlabia on head and pre-cloacal as well as specialized lateral 'sunflower' papillae comprised significant taxonomic information on systematics of ascaridoid (raphidascaridid) nematodes. Interestingly, these worms equipped with remarkably advanced features parasitized primitive host group like, Pisces, in the series of vertebrates, contrary to the characteristics of co-evolution in which parasitizing organism gradually acquired advanced features as it progressed up the ladder of evolution (from Pisces to Mammalia). In the parasitic world, therefore, the worm like Ancylostoma with its occupancy in the highly evolved group i.e. mammals obviously exemplified 'co-evolution', while on the contrary 'Reverse Co-evolution' was the event that was encountered in R. spinicaudatum.

Faunal change over 3 decades to reveal Rotundocollarette capoori n.gen., n.sp., a unique anisakid from Johnius dussumieri from the Central west coast of India at Goa

A unique anisakid roundworm, Rotundocollarette capoori n. gen., n.sp. infesting Johnius dussumieri from the Central West coast of India at Goa has been described. The worms are typically characterized by a cephalic collarette, a muscular collarette in post-caudal zone, intestinal caecum and a ventricular appendix. 3 pores, a part of cephalic infrastructure-a dorsal oral aperture, a dorso-laterally placed genital pore, and a sub-ventral excretory pore, at the junction of the bases of the 2 ventro-lateral lips, were typically unique as revealed by SEM studies. A pair of large squarish teeth flanked each of these three pores in the cephalic region, with 3-5 denticles in the median group, at the junction of the two arms of V-shaped structure, that joined 26-29 denticles on each arm of this V-shaped formation, running parallel and crossed past dentigerous ridges on each lip. In addition, a set of 49-50 medially organized denticles occupying the dorsal arm of V-shaped formation, in the medial space, were a conspicuous configuration, besides 70 min triangular denticles at the junction of sub-ventral lips. A spined mucron at the tip of tail. The key provided by Moravec and Justine (Parasite 27:58, 2020. 10.1051/parasite/2020053) to segregate Porrocaecum-like nematode genera (Porrocaecum, Pseudoterranova, Pulchrascaris, Euterranova, and Neoterranova) has been revised to include the newly proposed genus, Rotundocollarette capoori n.gen., n.sp. The significance of the emerging nematode as an environmental bioindicator has been specified.

Bioinvasion: a paradigm shift from marine to inland ecosystems

Anisakidosis is one of the most fearsome zoonotic food borne disease in aquaculture. The natural infections by anisakidoids or related variety in freshwater fish are not known, though sporadic experimental reports are available abroad (Butcher and Shamsi 2011). Invasive severity of anisakidoids in fish from Gangetic riverine ecosystems, i.e., in river Ganges at Fatehpur and Allahabad, as well as in river Yamuna at Allahabad, and molecular heterogeneity among these worms have been extensively investigated. The pathways of transmission of non-native alien species due to long distance migratory habits of Rita rita, man-made alterations including dredging in long stretches of the river bed of Ganges to facilitate ballast water transfer mechanism owing to the commercial ship movements between Haldia and Allahabad; and sudden water chemistry (salinity, hardness, alkalinity) alteration (due particularly to rainy period) oriented micro-fauna interchange are identified, and remedial measures suggested.

Ecological morphotaxometry of trematodes of garfish (Teleostomi: Belonidae) from Gangetic riverine ecosystem in India. I. Morphology and taxometric assessment of Cephalogonimus yamunii n.sp

A new endoparasitic fluke, Cephalogonimus yamunii n.sp. is described from the intestine of freshwater fish Xenentodon cancilla (Belonidae). The worms could be differentiated from C. amphiumae (Chandler 1932), C. apognichthysi (Gupta and Puri 1982), C. hanumanthai (Agrawal and Agarwal 1984), C. salamandrus (Dronen and Lang 1974), C. simhai (Singh 2010) and C. vesicaudus (Nickerson 1912) in a unipartite seminal vesicle, genital pore subterminal anteriorly, opening at the hind end of oral sucker, equatorial or sub-equatorial testes, besides other morphological attributes of shorter body and pharynx, larger oesophagus and oral sucker, smaller ventral sucker, testes, cirrus sac and ovary, and a terminal excretory pore. Taxometric substantiation has been presented by using Polythetic Divisive Classificatory System, and ecological attributes have been evaluated to validate specific distribution patterns in population dynamics of the new species in simultaneous contributions.

New data on the morphology of Iheringascaris inquies (Linton, 1901) (Nematoda: Anisakidae), a specific parasite of the marine fish Rachycentron canadum (Linnaeus), as revealed by SEM

Specimens of the type species of the ascaridoid genus Iheringascaris Pereira, 1935, I. inquies (Linton, 1901) (Anisakidae), were collected from the digestive tract and mesentery of its type host Rachycentron canadum (Linnaeus) (Rachycentridae, Perciformes) from off the Atlantic coast of South Carolina, USA, during May of 2011. Scanning electron microscopical examination, used for the first time for specimens originating from the West Atlantic, made it possible to study in detail some taxonomically important morphological features, such as the number and distribution of male caudal papillae, cephalic and cuticular structures, deirids and cloacal (anal) lips. The allocation of other, poorly described, species from different hosts in Indian waters to this genus needs to be confirmed.

Morphological and molecular diagnosis of anisakid nematode larvae from cutlassfish (Trichiurus lepturus) off the coast of Rio de Janeiro, Brazil

Anisakid nematode larvae from Trichiurus lepturus off coast of Rio de Janeiro were studied using light, laser confocal and scanning electron microscopy, in addition to a molecular approach. Mitochondrial cytochrome c-oxidase subunit 2 (mtDNA cox-2), partial 28S (LSU) and internal transcribed spacers (ITS-1, 5.8S, ITS-2) of ribosomal DNA were amplified using the polymerase chain reaction and sequenced to evaluate the phylogenetic relationships between the nematode taxa. The morphological and genetic profiles confirmed that, of the 1,030 larvae collected from the 64 fish examined, 398 were analysed, of which 361 were Hysterothylacium sp. and 37 were Anisakis typica. Larvae of Hysterothylacium sp. were not identified to the species level due to the absence of similar sequences for adult parasites; however, the ITS sequence clustered in the phylogenetic tree with sequences of H. deardorffoverstreetorum, whereas an mtDNA cox-2 and LSU concatenated phylogenetic analysis demonstrated the presence of two clades, both of them under the same name as the larval H. deardorffoverstreetorum. Data on the occurrence of parasites during the winter and summer months were compared using the t-test. The greatest prevalence and intensity of infection were recorded for larval Hysterothylacium, with a prevalence of 51.56% and an intensity of up to 55 parasites per fish. The larval Anisakis exhibit a higher abundance and intensity of infection in the winter months, and those of Hysterothylacium during the summer. However, the t-test indicated no significant differences between the abundance and intensity of infection recorded during the months of collection for either of these larval nematodes. All sequences generated in this study were deposited in GenBank.