Episomus

The weather-worn rails found along Taiwan trails are a good spot to find insects. On those trails where frequent rains and the yearly beat of typhoons has had their fill you can find so many creatures making homes in the seams. I found this little weevil plodding along the top of one-such railing in Neihu. They were courteous enough to stop walking as I loomed over to snap a few photos.

There are hundreds of weevil species in Taiwan, with more being found even today ([source])(url = "https://www.oist.jp/news-center/news/2024/10/30/12-new-oriental-weevil-species-discovered-using-advanced-imaging-tools"), though identifying them can be difficult. I found that many species, and even some families of weevils have not been fully researched. For this little guy, I was able to narrow the genus down to what I'm fairly certain is Episomus. There are only four species of this genus found in Taiwan, of which three are endemic:

• Episomus takahashii Kôno, 1928 (隆背象鼻蟲)
• Episomus chinensis Faust, 1897 (中國癩象) - Not endemic
• Episomus watanabei Kôno, 1932 (灰隆背象鼻蟲)
• Episomus albiguttatus (Matsumura, 1910) (Maybe 癩象屬)

The odd one out is Episomus albiguttatus, for which I couldn't find information with the Latin and Chinese names. Gagaphotos was the only site I could find showing a fourth Episomus species, so it could be the right one, but it's difficult to say if the photo is accurate. If the only noted finding was in 1910, I'm wondering if it exists, was misclassified, or if it's considerably rare. One thing I found was on this site about sea slugs:

The specific epithet albiguttatus is a Latin compound of albus ("white") and guttatus ("spotted, dotted"), meaning "with white spots", referring to the conspicuous white nodules on the dorsum.

This could match the photo, but going off a guess in Latin is not a fantastic indicator.

For the photo here, it leaves me guessing it's one of the other three. The name for Episomus watanabei in Chinese (灰隆背象鼻蟲), as well as the photos I found, insinuate a grayish coloring, whereas this one is more brown mixed with black. If I had to guess I'd say it is one of the latter two, and I'd lean towards Episomus chinensis, as the coloring and hind protuberances (apical tubercles) more closely match.

That being said, color is weak evidence, as the scales which lay on top of likely black cuticle will get scuffed and fade with age. I think this makes them look more distinguished, much like myself; aging like fine wine and all. A newly born weevil looks more evenly colored, so here it could be any of these, and having been around a bit longer.