Endeis biseriata Stock, 1968

Arango, Claudia P., 2003, Sea spiders (Pycnogonida, Arthropoda) from the Great Barrier Reef, Australia: new species, new records and ecological annotations, Journal of Natural History 37 (22), pp. 2723-2772 : 2759

Endeis biseriata Stock, 1968

Endeis biseriata Stock, 1968: 57–60 , figure 21; 1979: 28–30, figure 9; 1992: 134.

Endeis biserata (sic.): Child, 1988b: 20; 1990: 332–333; 1996b: 554.

Material examined. Pandora Reef, 4–6 m, in rubble, 7 March 2000, one W; 19 April 2000, one X, one W. Goold Island , reef slope, 7 m , in rubble and algae, 18 April 2000, one X, one W; 24 August 2000, six W, three X. Rib Reef , reef slope, 8 m , in zoanthids, 8 July 2000, one X. Lucinda jetty, 3 m , in pilings scrapes,? September 1999, seven X, four W with eggs (coll. J. Cruz). Townsville Marina , on fouling panels with bryozoans and hydroids, 2 m , 13 October 1999, one X.

Description. Trunk length 2.5 mm, width 1.3 mm, fully segmented, crurigers apart by twice their diameter, with two distal tubercles, ocular tubercle tall, conical shape, cephalon with collar, proboscis long, inflated at mid-point, with short setae around oral surface. Ovigers seven-segmented, the fifth the longest, small spinules in the two last segments. Legs long, second tibia the longest, femur with long distal tubercle and two smaller ones, both tibiae with dorsal row of setae, curved propodus without heel, three heel spines, eight sole spines, claw half the size of the propodus, auxiliaries half the size of the main claw. Cement glands 40–42 pores distributed in two irregular rows laterally on each femur.

Distribution. Endeis biseriata was first found in Australia by Child (1990) at Lizard Island, in similar conditions to those reported here. This is an Indo-west Pacific species distributed from the Red Sea and Madagascar to Indonesia, the Philippines and Hawaii. It might have a pantropical distribution. These collections are within the depth range known for the species.

Remarks. Collections from several reefs of the central section of the GBR added to the Lizard Island record suggest the species could be common and continuously distributed in tropical North Queensland. The size and relatively high abundance allowed observations of preference of substratum and feeding behaviour. A total of 22 adults of E. biseriata were found exclusively on the zoanthid Protopalythoa sp. Some adults were seen inserting the tip of the proboscis into a polyp and remaining attached for about 1 min, or crawling from one polyp to the other, repeatedly inserting the proboscis (Arango, 2001).