Ascorhynchus tenuirostris Carpenter, 1892

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 : 2726

Ascorhynchus tenuirostris Carpenter, 1892

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Ascorhynchus tenuirostris Carpenter, 1892: 555–557 , pls 7–14. Stock, 1954: 135. Ascorhynchus tenuirostre (sic.): Child, 1990: 311.

Material examined. Turtle Bay, collected among Cladophora prolifera from intertidal rocky patches on a sandy beach during low tide (<0.5 m), 14 May 1999, one juvenile. Swain Reefs, 46 m, collected by trawling, found amongst the green alga Halimeda sp. and rubble, 22 November 1999, one W (Department of Primary Industries, DPI sta. DW P422).

Description. Adult male specimen: trunk 2.16 mm long, 1.05 mm wide, fully segmented, single dorsomedian tubercle per segment, each tubercle with small spines; abdomen horizontal, reaching far from distal margin of first coxae of fourth legs; proboscis long, narrow, pyriform, carried ventrally, with proximal and distal sutures. Palps nine-segmented. Fourth and fifth segments of ovigers subequal, compound spines in three rows on seventh segment and two rows on distal segments, longer spines formula 6:3:3:5. Dorsodistal spur on femur, tarsus small with three short distal spines, auxiliary claws absent.

Distribution. Only known before from its type locality in Torres Straits, North Queensland.

Remarks. The adult specimen morphology agrees with the description of the holotype (Carpenter, 1892) except for fewer rows of spines on the eighth segment. Another four species of Ascorhynchus are known for Australia (Clark, 1963). Ascorhynchus longicollis Williams, 1941 and A. compactum Clark, 1963 lack the conspicuous median tubercles in the trunk, in A. minutum Hoek, 1881 these are much shorter and there are longer dorsal spurs in coxae. Ascorhynchus melwardi Flynn, 1929 has no trace of a second segment or palm in the chelifores and the body is more setose, it is known from Cape York and Singapore, probably being the closest relative of A. tenuirostris . Ascorhynchus cactoides , another Indo-Pacific species related to A. tenuirostris differs mainly in a more spinose trunk armature and a broader proboscis. Ascorhynchus tenuirostris can be easily recognized mainly by the narrow shape of the proboscis and the one-segmented scape.