印痕有五種，台灣的叫做「帝王仿相手蟹」(Sesarmops imperator)

原產於西印度洋的印痕仿相手蟹 (Sesarmops impressus), 以往認為廣泛分布於印度西太平洋一帶，經過三位作者 (Peter Ng、李政璋、施習德) 檢視形態，並利用分生證據的支持，確認印痕仿相手蟹僅產於西太平洋，其他地區的種類則另有四種。兩個舊種 S. similis, S. atrorubens 分別產於 Samoa 和 Fiji; 以及兩個新種, S. indicus (印度仿相手蟹) 產於東印度洋, S. imperator (帝王仿相手蟹) 產於西太平洋一帶，包括東亞與東南亞。帝王仿相手蟹，由於體色為紫色，屬於皇室專有的顏色，加上體型巨大，因此使用帝王 (imperator) 作為種小名。全文可於 Zoological Studies 下載 (http://zoolstud.sinica.edu.tw/Journals/59/59-27.pdf)。

Five species within the Sesarmops impressus complex, with one named as Sesarmops imperator (帝王仿相手蟹) from West Pacific

Sesarmops impressus is a large sesarmid inhabited in freshwater stream, with the type locality believed from western Indian Ocean. Originally it was considered to be distributed widely in Indo-West Pacific, but after the morphological and molecular studies by Peter Ng, JJ Li & HT Shih, there are 5 species within this complex. True S. impressus is limited in western Indian Ocean. Two old species, S. similis and S. atrorubens are distributed in Samoa and Fiji, respectively. Additional two new species, S. indicus is distributed in eastern Indian Ocean and S. imperator is distributed widely in West Pacific, incl. East Asia and Southeast Asia. Because the purple coloration, associated with royalty, and its large-sized, the name "imperator" was used as the specific name. The PDF could be downloaded from Zoological Studies (http://zoolstud.sinica.edu.tw/Journals/59/59-27.pdf).