From where did you collect it? Did you collect it from the blood of fish like Clarias or Heteropneustes? And in its ID, hooks are more important than the body measurment.
Dear Rakesh, I collected them from the entrails. Some of them are yellow colored and some are white and some hooks are little damaged. Have you maybe an ID key with the pictures of Acanthocephala species???
Can you run some genetic analyses? Some acanthocephalans can be differentiated using simple PCR/RFLP (differenciation between P. laevis and P. terreticolis for instance, see Perrot-Minnot 2004). You can take a look at Brown et al. 1986 for identification based on the proboscis morphology. More recent ID keys might also exist.
Article A key to the species of Acanthocephala parasitic in British ...
Article Larval morphology, genetic divergence, and contrasting level...
They look like a species of Pomphorhynchus (but appear to have been heavily flattened). Pomphorhynchus laevis (Zoega in Muller, 1776) is a common parasite of Barbus barbus, and Pomphorhynchus bosniacus Kiskaroly & Cankovic, l969 has also been recorded from this host.