Ammothella marcusi Hedgpeth, 1948

Müller, Hans-Georg & Krapp, Franz, 2009, The pycnogonid fauna (Pycnogonida, Arthropoda) of the Tayrona National Park and adjoining areas on the Caribbean coast of Colombia 2319, Zootaxa 2319 (1), pp. 1-138 : 31-33

Ammothella marcusi Hedgpeth, 1948

Figs. 12–13

Ammothella marcusi Hedgpeth, 1948: 247 . Child 1982: 358, (literature). Stock 1986: 400. Müller 1990: 278.

Material: 22.— 4 males, 2 fem. (gravid) ( SMF 1120 ), Halimeda on reef top, 14. IV.1986 . 28.— 1 male ( SMF 1121 ), under stones, ca. 0.5 m, 4.IV.1986 .

39.— 2 fem. (gravid) ( ZFMK), from stones, 0–0.5 m, 17.III.1986 . 3 legless adults ( ZMA 3352 ), from stones, mesolittoral, 14.IV.1986 .

Description of male: Trunk relatively compact, in outline almost circular, completely segmented. Cephalon antero-laterally with obtuse tubercle above base of palps. Ocular process relatively low, about 3 times as tall as broad, with pointed tip and darkly pigmented eyes. Crurigers 1–3 each with two pointed spinelike distal outgrowths on antero- and postero-lateral aspects, which almost touch their respective neighbours on adjoining cruriger; cruriger 4 with only one such outgrowth on antero- and postero-lateral aspects. Abdomen erect, 3 times as long as ocular process, with some clavate and simple setae of different lengths.

Proboscis oval, about 3 times as long as diameter.

Cheliphore scape two-articled, its distal article about 1,5 times length of its basal article, both articles tightly covered with clavate setae, mostly on lateral aspect; chela very short and stump-like. Palp 9-articled, 2 nd and 4th articles longest; articles 2 and 3 with single feathered seta, articles 4 and 5 with several feathered setae; articles 6–9 with short simple setae, mainly on ventral surface. Oviger 10-articled; articles 2, 4 and 5 elongated and of near equal length; 7 th article in its distal half with pair of robust spines; articles 8–10 bearing flat spines with serrated edges, largest on tiny terminal article. Legs relatively slender; coxae 1 of all legs with dorso-lateral pair of short, club-shaped setae; coxae 1 with about 2–4 dorso-distal clavate setae, and single simple lateral seta; coxae 1–3 of almost equal length; femur 5 times as long as broad, sparsely beset with clavate and simple setae; short (1/4 of femur diameter) dorso-distal cement gland duct; tibia 1, 1.2 times as long as femur, with ventral row of about 11 clavate setae; tibia 2 slightly shorter than tibia 1, covered by simple setae only. Propodus feebly curved and robust, no heel; basal half of sole armed with 4 robust, distal half with 5 smaller and more slender spines; main claw moderately curved, about half length of propodus; auxiliaries little shorter than main claws.

Measurements: Trunk length 0.68; width 0.70 (across 2 nd crurigers); length of abdomen 0.35; length of proboscis 0.50; length of cheliphores 0.52, leg 4: coxa 1, 0.26; coxa 2, 0.21; coxa 3, 0.23; femur 0.55; tibia 1, 0.77; tibia 2, 0.75; tarsus 0.09; propodus 0.33; main claw 0.14; auxiliary claw 0.11.

Female: In habitus very close to male, but the lateral spiniform tubercle on the lateral processes more feeble. 2 nd article of ovigers in females shortened, 7 th article without the robust pair of spines, 3 flat serrated spines in their place.

Remarks: The species seems most closely related to Ammothella hedgpethi Fage, 1953 from the eastern Atlantic (Dakar), which resembles it but is somewhat more robust and lacks the lateral spiniform tubercles on the lateral processes (see Fage 1953b: 376).

A. marcusi has been sampled very scarcely, no sound data on preferred substrata or phenology are available.

Distribution: Tropical western Atlantic. All previous records were summarised in Müller (1990d: 278).

Figures

FIGURE 12. Ammothella marcusi Hedgpeth, 1948: A male dorsal, B male lateral, C male cheliphore, D female oviger, E distal 5 articles of female oviger.

FIGURE 13. Ammothella marcusi Hedgpeth, 1948: A male palp, B male leg 4.