Sakai, 1937
This new species is so closely allied to Leucosia haswelli Miers that only the points of difference between the two need be pointed out.
1. The carapace excluding fronto-orbital region is almost circular and globular, its upper surface being polished and punctate on the anterior surface. There are two impressed whitish spots on either side of the gastric region, similar in position to those of Leucosia longifrons; they are followed posteriorly by an indistinct whitish line on either side of the cardiac region. Contrary to haswelli, which has two large blotches near the posterior surface, the new species has a number of indistinct dark blotches on the upper surface.
2. The front is as in haswelli slightly produced beyond the eyes, its anterior margin being subtruncate or sinuate.
3. The antero-lateral borders are very slightly convex; they are marked by numerous granules extending from the posterior angle of the orbit to the level of the base of the first ambulatory legs; these granules are microscopical in the anterior half, but they regularly increase in size posteriorly.
4. The ventral surface of the ischium of the external maxillipeds of the female is armed with a prominent tubercle near the distal extremity, which is rudimentary in haswelli. There is a row of brown hairs along the inner border of the ischium and merus, but the hairs are worn out in the distal half of the latter segment.
5. The thoracic sinus is, contrary to haswelli, not typically Y-shaped, the limbs of the Y being short and asymmetrical, but the tail of the Y being defined by four or five large pearl-like granules as in haswelli.
6. The arm of the chelipeds is characterized by having the distal one third abnormally broadened. Upper proximal surface with three or four tubercles arranged obliquely in longitudinal line, and proximally to this line, there is a patch of about eight flat granules which are partly concealed by tomentum. The anterior border of this segment has a row of about seven or eight tubercles of irregular size, while its posterior border has a row of eleven or twelve milled tubercles and also inside of this row are about four tubercles. The anterior surface of this segment is closely covered with tubercles of various sizes except the distal surface, while the under surface is almost smooth. The wrist is provided with a row of four or five small granules along the inner border, the palm with its inner border granulated, the granules becoming smaller distally and finally continuous with the median sulcus of the immovable finger. Below this row of granules, there is also a row of punctuations. The outer border of palm is obtuse and not carinate as in Leucosia haswelli.
7. The merus of the ambulatory legs has a row of granules along the posterior border; the propodus and dactylus are compressed and carinate on both edges. (Sakai, 1937: 144)
Type locality: Hôzan, Kaohsiung, Taiwan.
Range: Taiwan - Kaohsiung (Sakai, 1937a), Fengshan and Kaohsiung (Lin, 1949); China - Guangdong and Fujian; Gulf of Tongking (Zarenkov, 1990); Philippines.