Ammothella sp.

Bravo, Maria Fernanda Montoya, Müller, Hans-Georg, Arango, Claudia P., Tigreros, Paulo & Melzer, Roland R., 2009, Morphology of shallow-water sea spiders from the Colombian Caribbean, add _ journal _ name _ here 32 (1), pp. 9-34 : 21-22

Ammothella sp.

Material. Juvenile (ZSM-A- 20071603), Bahia del Rodadero, Santa Marta; from brown algae on buoy; 0-0.3 m; 14.12.2004 ; Juvenile (ZSM-A-20060993), Bahia de Taganga, Santa Marta; under stone; 0-0.5 m; 05.01.2005

Description ( Fig. 12)

Living pycnogonid sand-coloured to transparent yellowish. Body of oval shape, with very long legs ( Fig. 12A). Segmentation completely visible ( Fig. 12B,C). Dorsal side of trunk smooth except for small branched hairs and gland pores distributed over the whole body surface ( Fig. 12C). Spines and protrusions absent distally as well as in the region of the coxae.

Eye tubercle with 4 pigmented eyes, 4× as long as wide, with pointed tip and one apical and 2 lateral sense organs as well as some branched hairs ( Fig. 12B). Abdomen 1.5× as long as eye tubercle ( Fig. 12B), dorsoproximally with 2 short setae, and 2 longer setae further distally. Abdomen fused with trunk segment 4 ( Fig. 12B).

Chelifores robust, composed of 3 articles ( Fig. 12B). 1 st of these short and thin, 2 nd becomes wider distally, thus being club-shaped. This article with long lateral and club-shaped dorsal bristles showing an irregular pattern. Chelae with some long spines at their base. Inner sides of fingers with pointed teeth. Palps made of 9 articles with numerous spines ( Fig. 12B). Of these, 2 and 4 are the longest. Ovigera as yet not developed in our specimen.

Legs very long and slender ( Fig. 12 D-J), with several spines and setae laterally and distally on each article. Coxa 2 dorsodistally with 2 long setae. 2 nd coxa 2× as long as coxa 1, having 2 dorsal setae and a couple of thin spines ( Fig. 12D). Femur rather thin, 4× as long as coxa 3. Dorsomedially and distally with a single long, thin spine. Further distally on each side one seta. Distal tip of femur on each side with one slender spine ( Fig. 12E). Tibia 1 slightly longer than tibia 2, both are thin and are armed with a similar number of spines arranged in a corresponding way. At ¼ of the length of tibia 1, are 2 setae and on the side 2 long spines. In the distal area and at the tip with further setae and several spines. Tibia 2 with several long spines dorsally ( Fig. 12F) and smaller spines everywhere on the surface ( Fig. 12G). Tarsus 0.25× as long as wide, equipped at the ventral side with one robust and several small spines ( Fig. 12H). Propodus slender, slightly curved, at its base armed with two large, pointed spines ( Figs 12H). Sole with row of 6 small spines and anterior pair of spines ( Fig. 12I). Main claw 0.75× as long as propodus. Accessory claws very long and thin, 0.8× as long as propodus ( Fig. 12I).

Remarks. Ammothella sp. is a small, slender species sampled from brown algae on a buoy. It was not possible to determine this species, since it is a juvenile not similar to juveniles of other Caribbean species of Ammothella . The eye tubercle is much longer than in other Ammothella species. The most similar species are A. spinifera and – to a lesser extent – A. appendiculata . However, our specimen can easily be distinguished form A. appendiculata as having no distal spination, and even the juveniles of A. spinifera possess at least precursors of the spines of the 2 nd segment that are missing in our pycnogonid. This also accounts for the spination of the legs: e.g., the setae of coxa 1 are lying side by side and not in a longitudinal row as in A. spinifera , and the other leg articles are different from the two other Ammothella as well. Another obstacle is the absence of ovigera in our juvenile. Hence, our specimen might be a juvenile of a previously undescribed species. Since we found only one single individual, further samples and studies will be necessary to assign this individual to a species.