Originally posted by sswroom at 2010-12-31 01:47
The body length is around 18mm.
Wow. That is rather big already. I don't suppose you included the appendages in that?
Anyway, I did a little reading and all that I can find seems to indicate that only Ligia exotica
is recorded for the region. All the visible features (length of antennae and uropodes and the shape of the telson) seem to fit well for this species also and with L. exotica
being a rather large species the 18mm are even still okay for a younger animal. So that all seems to come together nicely.
However, I should keep a little margin for error here as I don't have much literature on Asian woodlice and some new species or records may have been published that I don't know about. The whole of the western pacific is fairly rich with species of Ligia
, most of which look so much like L. exotica
that they have always been mistaken for this species historically and only recognized/described as separate species in the past few decades.
Closest to HK Ligia taiwanensis
Lee, 1994 might be noteworthy (from Taiwan of course) and a number of endemic species from various Japanese islands have been described between 1979-1999. Only Ligia cinerascens
Budde-Lund, 1885 (from the Kuril islands) carries an older date.
It would not be very surprising if it turns out that the some of the animals from the shores of HK that have so far been IDed as "Ligia exotica
" would at some point be proven to be a new lookalike species.
The other reason for caution is that with Hong Kong being the important harbour that it is (and always has been, especially when tall ships were still made of lumber) there is always the prospect of species from the other side of the ocean hitching a ride on a vessel. This way for example the northern European Ligia oceanica
has found its way to the American east coast. Of the American west coast species only Ligia baudiniana
Milne Edwards, 1840 might come close morphologically, but I don't think this is one. Still, with the harbour and all one would always have to take some introduced species into account too, which makes me a bit nervous about setting you up with a "fixed" ID.
Nevertheless Ligia exotica
seems to be the best option by far. Hopefully someone more savvy about Asian woodlice will be able to confirm the ID, but I should better still leave a tiny "cf." in place: Ligia cf. exotica