Echinoderes tchefouensis Lou, 1934

Sørensen, Martin V., Gąsiorowski, Ludwik, Randsø, Phillip V., Sánchez, Nuria & Neves, Ricardo C., 2016, First report of kinorhynchs from Singapore, with the description of three new species, Raffles Bulletin of Zoology 64, pp. 3-27 : 19

Echinoderes tchefouensis Lou, 1934

Material examined. Echinoderes tchefouensis appeared on stations SI-01, SI-03, and SI-06, and was hence the most ubiquitous species in the area. A total of six adult specimens were mounted for LM, and deposited at the Natural History Museum of Denmark, under catalogue numbers ZMUC KIN- 857 to KIN- 862.

Notes on taxonomy and distribution. The species was originally described from the Yantai area on the Chinese Northeast Coast ( Lou, 1934). The original description was rather poor, and would in itself fit dozens of Echinoderes species. However, R. P. Higgins later collected specimens of Echinoderes in the area, and considered these to be conspecific with E. tchefouensis . Later, Higgins & Kristensen (1988) provided a note about the unusual lateral spine pattern in these specimens, with lateroventral spines/tubes on segments 5, 8 and 9 only. This enabled Sørensen et al. (2012a) to identify numerous specimens from adjacent waters as E. tchefouensis , and, based on these, provide a redescription that met present days’ requirements. The species is easily recognised because it lacks lateroventral spines on segments 6 and 7, combined with the presence of regular-sized glandular cell outlets type 2 in subdorsal position on segment 2, and a pair of extraordinary large outlets in laterodorsal positions on segment 8 (see Sørensen et al., 2012a for additional characters).

The record of E. tchefouensis in Singapore increases the known distributional range of the species, and makes it one of the apparently most widely distributed species of Echinoderes . According to the collectings of Sørensen et al. (2012a) the species covers an area from the Korean Peninsula in northeast, to an easternmost occurrence near Saipan Islands in the West Pacific, and south through the East China Sea and the Philippines, to Sipadan in Malaysian Borneo that until now has marked its southernmost point of distribution. However, the record of the species in Singapore, suggests that it not only has a wide West Pacific distribution, but also could be widespread in the Indonesian Archipelago, and perhaps even could extent into the Indian Ocean. With such a wide distribution, the species would be ideal for population genetic studies, where haplotypes from geographically very distant populations could be compared.

Another interesting finding is the appearance of E. tchefouensis at the intertidal station SI-06. Until now, the species has mostly been recorded from subtidal stations (9–140 m according to Sørensen et al., 2012a). The only other intertidal record of the species is from Saipan in the Northern Mariana Islands ( Sørensen et al., 2012a). Apparently the species is not only widely distributed, but also highly opportunistic and able to adapt to different habitats.