Description of Pallisentis thapari n. sp. and a re-description of Acanthosentis seenghalae (Acanthocephala, Quadrigyridae, Pallisentinae) using morphologicaland molecular data, with analysis on the validity of the sub-genera of Pallisentis.

Abstract

One new species of Pallisentis Van Cleave, 1928 is described from Channa punctatus (Bloch) from Gomti River (tributary of the Ganga River), in Uttar Pradesh, Lucknow district, India. Pallisentis thapari n. sp. is characterized morphologically by individuals having a globular proboscis armed with rooted hooks in 4 circles of 8-10 hooks each, the first circle more than 100 long and hooks gradually declining in size posteriorly. The trunk is cylindrical, with collar spines comprised of 15-17 complete circles of spines, each ring with 12-22 spines. As common in members of the genus, a narrow spine-free zone lies in between the rings of collar and trunk spines. Field of spines extends posteriorly to half of the body length, ending above the level of testes in males and slightly past mid-body in females; trunk spines have an optically-dense Y-shaped core. The trunk is only slightly wider at the anterior end. The syncytial cement gland of males contained 23-30 nuclei. Individuals of Channa striatus Bloch from the same locality also were infected with the new species. A second species of Acanthocephala, Acanthosentis seenghalae Chowhan, Gupta, Khera, 1988, was found as a parasite of Puntius sophore (Hamilton) from the same locality. The proboscis is short, globular, with 3 circles of hooks each circle bearing 6 hooks. The trunk is broad in the middle and tapered at both ends, with the posterior end narrower than the anterior end. Twelve to 16 circles of spines, each with 21-40 spines, extend from anterior end to just past mid-body in males and only to mid-body in females. The syncytial cement gland of males contains 6-10 nuclei. The analysis of 18s rDNA identified two clades of a monophyletic Pallisentis and placed the isolate of P. thapari n. sp. within that clade; previously established subgenera were not supported by the results of the analysis.