Tanystylum cinctum Child 1992

Tanystylum cinctum

MATERIAL EXAMINED.—ECUADOR. Bahia de Santa Elena, 02°13′09″S, 80°54′38″W, 3 m, sta 16–6671, 8 May 1966, 1 (holotype, USNM 234566), 1 with eggs, 4 (paratypes, USNM 234567).

DESCRIPTION.—Size very small; leg span 4.3 mm. Trunk circular, unsegmented, with partial fold or crease dorsally between ocular tubercle and abdomen. Lateral processes contiguous, each armed with a low conical dorsodistal tubercle bearing a short seta, except posterior pair, and a low rounded tubercle with seta on anterolateral surface of each lateral process except anterior pair. Cephalic segment extending only slightly beyond circle formed by contiguous lateral processes, armed at anterolateral corners with very short spine on low tubercle. Ocular tubercle large, almost at anterior of cephalic segment on elevated surface, about 1.5 times taller than its base, with a tall nodose apical cone at anterior and low rounded tubercle posteriorly. Eyes large, darkly pigmented, anterior pair larger than posterior pair, lateral sensory papillae prominent. Abdomen long, twice length of basal swelling, tapering slightly from basal bulge to pointed tip bearing 7–8 short setae. Abdomen placed well anterior, anterior of base in line with juncture of second and third pair of lateral processes, posterior not reaching to tips of fourth lateral processes and allowing their juncture to appear in dorsal view.

Proboscis bottle-shaped, broad at base, sides tapering gradually to become concave near tip. Mouth and lips small, flat.

Chelifore stumps large, with broad bases in dorsal aspect, carried bent dorsally, almost erect, armed with 5–6 short distal setae.

Palps 6-segmented, first five segments as long as proboscis. First and second segments subequal in length, third only half as long as its diameter, all armed with 1–2 short lateral setae. Fourth segment longest, three times longer than its diameter, armed with several short lateral setae, fifth segment little longer than its diameter, armed with 3–4 ventral setae, sixth segment long, slender, twice length of fifth, armed with few ventral and distal setae as long as segment diameter.

Ovigers typical, fourth and fifth segments longest but only about three times their diameters, seventh segment with lateral apophysis bearing three apical setae not as long as segment diameter and two slender endal spines. Eighth segment carried anaxially on seventh, armed with 2–3 ectal setae, without endal spines. Ninth segment slightly smaller than eighth, armed with one ectal seta and one endal plain spine, tenth segment smaller, only slightly longer than wide, with two distal spines each bearing pair of lateral teeth distally.

Legs also typical, with three dorsal bulges bearing setae on tibiae. Femur slightly longer than tibiae, bearing very short cement gland tube dorsodistally on large tubercle flanked by smaller tubercles with setae. Propodus robust, well curved, with three broad heel spines and several shorter sole spines. Claw large, broad, well curved, auxiliaries slender, slightly over half main claw length.

Female: Trunk and legs slightly larger, tubercles smaller or lacking on lateral processes. Ocular tubercle apical cone not as tall. Oviger smaller, typical for females, without denticulate spines or lateral teeth on terminal segment.

MEASUREMENTS (holotype, in mm).—Trunk length (chelifore insertion to tip 4th lateral processes), 0.63; trunk width (across 2nd lateral processes), 0.61; proboscis length, 0.36; abdomen length, 0.28; third leg, coxa 1, 0.14; coxa 2, 0.15; coxa 3, 0.13; femur, 0.39; tibia 1, 0.33; tibia 2, 0.33; tarsus, 0.09; propodus, 0.28; claw, 0.16.

DISTRIBUTION.—The new species is known only from the type-locality, Bahia de Santa Elena, Ecuador, in 3 meters.

ETYMOLOGY.—The species name (Latin: cinctum, a girdle, belt, or zone) pertains to the belt of the equator and thus to Ecuador, its type-locality.

intertidal