Additional Morphological Features and Molecular Data of Paracamallanus cyathopharynx (Nematoda: Camallanidae) Infecting Clarias gariepinus (Actinopterygii: Clariidae) in Kenya

Abstract

This study provides additional taxonomic features based on scanning electron microscopy (SEM) and molecular data for Paracamallanus cyathopharynx ( Baylis, 1923 ) (Nematoda: Camallanidae). Parasites were collected from the posterior end of the intestine of cultured freshwater Sharptooth catfish Clarias gariepinus (Burchell, 1822) from Kibos fish farm, Kisumu County, Kenya, from December 2017 to March 2018. Additional taxonomic features recorded for P. cyathopharynx include the occurrence of 4-5 equal length digitate processes on the caudal end of the female, 4 processes (2 smaller and 2 larger) on the male caudal end, and a description of the shape of the distal tip of the right spicule. The study provides SEM images of the exposed sclerotized buccal capsule. This gives more information on the tridents, the sclerotized plate that extends laterally from the buccal capsule, and the narrow isthmus separating the anterior buccal capsule from the posterior. The prevalence, intensity, mean intensity, and mean abundance was 52.91%, 2-38, 12.37 and 6.54, respectively. 18S rDNA fragments were amplified, sequenced, and compared to other camallanid taxa, and 18S data confirmed the identity of the newly obtained sequences (MN396556) as that of P. cyathopharynx, being identical to sequence DQ813445 from Tanzania. This represents the first geographical record of P. cyathopharynx in Kenya.