Prototrygaeus contrarius Child 1992

Prototrygaeus contrarius

MATERIAL EXAMINED.—ECUADOR. Outer Gulf of Guayaquil, 03°19′S, 80°43′W, ∼80 m, Menzies trawl, sta 18B-769D, 10 Sep 1966, 1 (holotype, USNM 234564), 1 juv (paratype, USNM 234565).

DESCRIPTION.—Size moderately small; leg span 8.3 mm. Trunk slender, fully segmented, without tubercles or setae. Lateral processes extremely attenuated, slender, cylindrical, separated by half to as much as their diameters at their bases, glabrous, span of second lateral processes greater than trunk length. Ocular tubercle long, cylindrical, placed at anterior of cephalic segment, bearing tiny slender tubercle at apex. Eyes large, slightly pigmented, placed at apex of tubercle, posterior pair slightly larger than anterior pair.

Proboscis slender, gradually swelling distally before constricted tip with small rounded lips. Proboscis shorter than chelifores. Abdomen very long, extending to midpoint of second coxae of fourth legs, cylindrical, slightly swollen distally, carried horizontally, armed with few short distal setae.

Chelifores very long, slender, scape of two segments, second slightly more than three times length of first, second armed with 4–5 long dorsodistal and lateral setae, each 2–3 times as long as segment diameter. Chelae atrophied, with hint of fingers remaining as two distal knobs, armed with single lateral seta longer than chela diameter.

Palps short, not as long as proboscis, 8-segmented, armed with a short distal seta on third segment, 5–6 longer setae on fourth, terminal four segments with 4–5 long ventral and lateral setae, as long as twice segment diameter. Terminal segment a knob of reduced diameter hardly longer than wide.

Oviger 10-segmented, slender, second segment longest, fourth about 0.6 as long as second, third and fifth subequal, shorter than fourth. Second segment armed with two distal setae, fourth with 2–3 short distal setae, fifth with one lateral and two longer distal setae. Sixth segment with 6–7 long lateral setae, seventh joined anaxially to sixth, armed with two very long laterodistal setae, eighth with two similar setae and one endal short spine. Ninth segment a curved cylinder twice as long as wide, unarmed, tenth a tiny bud as wide as long, armed with two short terminal broad spines lacking serrations.

Legs very setose with many very long lateral setae on coxae and major segments. First coxae with pair of long laterodistal setae, second with 3–4 long lateral and ventrodistal setae, third coxae with same form of lateral setae and several ventral setae. Femur with 7–8 long proximoventral setae and three pairs of medianlateral setae. Cement gland dorsodistally with slender tube slightly shorter than segment diameter pointing distally. First tibiae with several long dorsal setae, 4–5 pairs of long lateral setae and several long ventrodistal setae. Second tibiae with similar dorsal and lateral setae and many shorter ventral setae along length of segment. Tarsus very short, with long dorsal seta and several shorter ventral setae. Propodus slender, slightly curved, armed with 4–5 dorsodistal setae longer than segment diameter, eight short lateral setae, four slender heel spines and 11–12 slightly shorter sole setae. Claw half propodal length, well curved, armed with 4–5 endal teeth pointing distally, increasing in size distally. Auxiliary claws as long as main claw, very slender, well curved.

Female: Unknown.

Juvenile: Chelae with simple pincer-like fingers lacking teeth. Trunk more stout, ocular tubercle much broader, capped with round knob at apex. Palp 8-segmented, ovigers incompletely formed in specimen available.

MEASUREMENTS (holotype, in mm).—Trunk length (chelifore insertion to tip 4th lateral processes), 0.91; trunk width (across 2nd lateral processes), 1.02; proboscis length, 0.5; abdomen length, 0.56; second leg, coxa 1, 0.19; coxa 2, 0.38; coxa 3, 0.33; femur, 0.72; tibia 1, 0.78; tibia 2, 0.7; tarsus, 0.07; propodus, 0.32; claw, 0.16.

DISTRIBUTION.—Known only from the type-locality, the outer Gulf of Guayaquil, Ecuador, in about 80 meters.

ETYMOLOGY.—The species name (Latin: contrarius, against, opposite) refers to the lack of agreement or contrariness in appendage segment counts between this new species and the type of the genus, Prototrygaeus ammothelloides Stock, and to the fact that the two species are found on opposite sides of the South American Continent.

DISTRIBUTION.—It is surprising to find this species as far south as the Isla San Felix off the Chilean coast in 75 meters. The species was described from a Galapagos Islands type series found in 0–6 meters. Until the present specimens were collected, it had not been recorded from any other place and was not known from the mainland.

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