Tanystylum isthmiacum Stock, 1955

Bamber, Roger & Takahashi, Yoshie, 2005, Some littoral sea spiders (Arthropoda: Pycnogonida) from Ecuador, with a new species of Anoplodactylus Wilson, 1878 (Phoxichilidiidae), Zootaxa 815, pp. 1-8 : 3

Tanystylum isthmiacum Stock, 1955

Stock, 1955, 247–249, Fig. 17.

Material: 2 females, 3 males (one carrying eggs), Playas, Guayas Province, 02º38.23’S 80º23.3’W, 29 July 2001, low water ( BMNH 2004.2904–2908). 1 female, 2 males (one carrying eggs), Playas, 11 August 2001, mid water ( BMNH 2004.2909–2911).

Remarks: Other specimens have been taken from Salinas, 02º11.67’S 80º58.85’W, Data, 02º41.42’S 80º20.17’W, and Cenaim, 01º57.62’S 80º43.72’W, all in Guayas Province.

This species has a distinct ectodistal apophysis on article 7 of male oviger. Previous records are from the Pacific Coasts of Costa Rica ( Isla Cocos), Mexico, Panama ( Isla Taboguilla, type locality) and Ecuador (also at Salinas; Stock, 1975b), from the intertidal to at least 6 metres depth ( Child, 1979). Stock (1955) discussed the differences from T. oculospinosum Hilton, 1942 (= T. duospinum Hilton, 1939 , see Child, 1996) based on Hedgpeth's re­examination (not publ.). Stock (1966) divided the species into two subspecies on the basis of proboscis morphology and number of palp segments. The Ecuador material would fall into the nominate subspecies T. isthmiacum isthmiacum . The subspecies T. i. difficile Stock, 1966 has an Atlantic and Caribbean distribution.