Preliminary Study Of Freshwater Crab Gastric Mill Morphological Characteristics And Its Roll In Taxonomy

Objectives:To research on taxonomical criteria and measures of establishing novel species of freshwater crabs by studying gastric mill of Family Parathelphusidae Genus Somanniathelphusa, Family Potamidae Huananpotamon lichuanense, Genus Sinopotamon, Genus Nanhaipotamon and Genus Johora using digital video microscope and SDC measuring software, based upon previous multi-criteria taxonomical research on teeth plate of urocardiac ossicle of gastric mill from 64 samples of Sinipotamon wanzaiense and comparing with holotypes, and To discuss the taxonomical value of gastric mill of freshwater crabs.Conclusion :Gastric mill can be used as a novel taxonomical criterion of freshwater crabs. Male and Female adult freshwater crabs have similar structural gastric mill, which can be used as a complemental taxonomical criterion instead of using the first pleopod of male crabs traditionally. Zygocardiac ossicle has less taxonomical value comparing with urocardiac ossicle due to its diverse characteristics. Further research is required to determine the value of zygocardiac ossicle in taxonomy of freshwater crabs. The results shows that gastric mill is a useful amendment and supplementary of current morphological classification system of freshwater crab.