Invasive records of Eriocheir hepuensis Dai, 1991 (Crustacea: Brachyura: Grapsoidea: Varunidae): Implications and taxonomic considerations

A review of the genus Eriocheir De Haan, 1835 and related genera, with the description of a new genus and a new species (Brachyura, Grapsoidea, Varunidae)

“…12A, the minimum evolution tree of Eriocheir COI sequences with bootstrap support values). However, the classification proposed by Naser et al (2012) does not seem to be sufficiently supported by their DNA analysis, mainly because the partial sequences of COI used by them seem to be rather short (<700 bps) for the case of Eriocheir. Moreover, from the ecology of the crabs of the genus Eriocheir it is known that strong migration and frequent cross-breeding are commonly observed (see, e.g., Naser et al, 2012: 71-72, and references cited therein), phenomena that obviously influence intraspecific as well as interspecific variability.…”

“…As already remarked above, DNA analysis may be useful in some ways, but it remains still unknown how the patterns observed in the base-arrangements reflect the patterns found in the morphological characters. Individual specimens are more or less different in their base-arrangement, even if they belong to the same species, as seen in other animals, so differences or similarities in base-arrangements could only be used very carefully in making final decisions about species boundaries, and then only in combination with reliable morphological characters (perhaps in the sense of the study by Naser et al, 2012, but then even more extensively). In view of this observation, it would seem to be still harder to make decisions at generic level using DNA analysis.…”

“…Remarks.-Eriocheir japonica (De Haan, 1835) has a wide distribution; Sakhalin, Japan (Hokkaido, Honshu, Shikoku, Kyushyu, the Ryukyu Islands including Kuroshima between Ishigaki-jima and Iriomote-jima), the western coast of Taiwan (Guo et al, 1997), the south-eastern coast of the Korean Peninsula, and the central and southern coasts of China (Naser et al, 2012). Type locality.-Japan (De Haan, 1835).…”

“…The DNA analysis performed by Naser et al (2012) indicates that mitten crabs are to be assigned to six species belonging to three genera, i.e., Eriocheir japonica (De Haan, 1835), E. sinensis H. Milne Edwards, 1853, E. hepuensis Dai, 1991, and E. ogasawaraensis Komai et al, 2006, as well as Neoeriocheir leptognatha (Rathbun, 1913) and Platyeriocheir formosa (Chan et al, 1995) (cf. Naser et al, 2012 fig.…”

“…The mitten crabs (Brachyura, Varunidae, Varuninae) as currently conceived (e.g., Naser et al, 2012), would allegedly comprise six species belonging to three genera, i.e., Eriocheir japonica (De Haan, 1835), E. hepuensis Dai, 1991, E. ogasawaraensis Komai, Yamasaki, Kobayashi, Yamamoto & Watanabe, 2006, E. sinensis H. Milne Edwards, 1853, Neoeriocheir leptognatha (Rathbun, 1913), and Platyeriocheir formosa (Chan, Hung & Yu, 1995). In the present study, however, it has turned out through exact examination and detailed comparison of the external morphological characters of these forms, including the male Plp1, that in the opinion of the present author they are to be reclassified into four genera including one new genus, and seven species including one new species, while one species, currently unnamed, remains as a species inquirenda.…”