“Austrodecus pushkini, new species, Fig. 8
Material examined. Hero: 715-864, (one male, one female (paratypes, USNM 234614)), 715-865 (one female (paratype, USNM 234613)), 715-873 (one male, two females (paratypes, USNM 234612)), 715-874 (three females (paratypes, USNM 234611)), 715-875 (one male (holotype, USNM 234609)) two females (paratypes, USNM 234610)).
Other material. Eltanin: 11-960 (two males, seven females). Hero: 715-907 (one male, one female), 715-908 (one female).
Distribution. Known only from the type locality, Tierra del Fuego off Peninsula Mitre and Isla de Los Estados, Argentina, in 60-903 m.
Diagnosis. A species of the A. glaciale section. Trunk compact with closely crowded and very short lateral processes. Trunk with very low but broad dorsomedian tubercles increasing in height from anterior small bump to posterior large tubercle. Ocular tubercle short, broad, eyes prominent. Palps and ovigers conventional. First coxae of first and fourth leg pairs with single conical dorsodistal tubercle, first coxae of second and third leg pairs with two conical dorsodistal tubercles, the posterior tubercle smaller than the anterior tubercle on any one coxa. Cement gland orifice a slender ventromedian tube at the apex of a broad conical base. Propodi longer than second tibiae, auxiliary claws 0.5 to 0.6 times length of main claw.
Description. Size rather large among species of this genus, male leg span 7.6 mm. Trunk compact, lateral processes closely crowded and shorter than half their diameters. Trunk with broad low dorsomedian tubercles bearing short setae. Anterior tubercle lowest, a mere bump, each succeeding posterior tubercle taller until that at base of abdomen tubercle is almost as tall as its basal diameter. Ocular tubercle short, broad, with prominent posterior basal “tuck” or curve. Abdomen moderately long, slightly inflated proximally, reaching to distal tip of second coxae of fourth legs. Proboscis typical, moderately long.
Palps also typical of genus, long first segment arising from basal tubercle. Third segment about 0.6 length of first, armed with three stout curved endal spines and few setae. Terminal segment tiny, carried synaxially on slightly longer penultimate segment, both armed with fields of short ventral and distal setae.
Ovigers typical, 6-segmented, that of male slightly larger and more robust than slightly shorter and more slender oviger of female, both armed with 3-5 short distal setae on terminal segment and 2 short lateral setae on fourth segment.
Legs short, robust, armed with few short setae and typical long dorsodistal spine on major segments. First coxae of first and fourth leg pairs with single dorsodistal conical tubercle, first coxae of second and third leg pairs with two dorsodistal tubercles of unequal size, the posterior tubercle of each pair being smaller than the anterior tubercle. Second coxae with several low dorsodistal and laterodistatal papillae. Cement gland orifice at tip or short tube at apex of low cone placed at midventral point of femora. Second tibiae shorter than propodi which are moderately curved and armed with very few sole spines, dorsal setae, and robust short main claw. Auxiliaries about 0.6 length of main claw.
Measurements (holotype in millimeters). Trunk length (palp insertion to tip fourth lateral processes), 0.9; trunk width (across first lateral processes), 0.52; proboscis length, 0.84; abdomen length, 0.24; third leg, coxa 1, 0.27; coxa 2, 0.36; coxa 3, 0.28; femur, 0.74; tibia 1, 0.61; tibia 2, 0.45; tarsus, 0.13; propodus, 0.49; claw, 0.21.
Etymology. This species is named for A. F. Pushkin, of the Zoological Institute, Academy of Sciences, St. Petersburg, Russia, for his contribution to this genus (A. kelpi Pushkin, 1977).
Remarks. This species is closely related to A. kelpi Pushkin, and indeed was mistaken for that species until the male cement gland orifice of this species was compared with Pushkin’s figures. Very few species of Austrodecus have a very long tubular cement gland orifice with or without a cone at its base. The only species known with this character are A. aconae (Hedgpeth and McCain, described as Pantopipetta), A. kelpi Pushkin, A. tubiferum Stock, and A. staplesi Stock.
The latter two species differ from A. pushkini in having longer and very slender dorsal tubercles on the trunk and first coxae, by having mitten shaped terminal palp segments, and by belonging to the A. gordonae section of the genus, with 4-segmented ovigers and auxiliary claws which are vestigial or absent.
The news species is quite different from A. aconae by virtue of that species’ having a very slender attenuated habitus, a long slender and erect ocular tubercle, and three terminal palp segments (a situation thus far unique among the known Austrodecus species) arranged anaxially, and also by being a member of A. gordonae section.
There can be little doubt that the new species is closely related morphologically with A. kelpi, a relatively distant but nevertheless Subantarctic neighbor from the South Sandwich Islands. They are both compact with short lateral processes and ocular tubercles and have low broad dorsomedian trunk tubercles, very similar palps and proboscis, similar ovigers, and legs of approximately the same segment length rations. They differ fro the most part in the legs. The first coxae of the fourth leg pair of Pushkin’s species have two dorsodistal tubercles, with the posterior one smaller than the anterior tubercle. The same first coxae of this new species have a single tall tubercle and a tiny papilla in place of the smaller tubercle of Pushkin’s species. Other differences are found in the cement gland orifice which is a long tube on a very low basal bump in A. kelpi and a cone with short tube in A. pushkini. The cement gland tube of Pushkin’s species is located proximal to the ventral midpoint, while the cone and tube of the new species are on the ventral midpoint. The ocular tubercle of the two species is short and broad, but that of A. kelpi is only rounded dorsally while that of the new species is straight and has a “tuck” or proximal hump on its posterior.” (Child 1994b, p.69-71)
