Comprehensive DescriptionRead full entry
“Achelia lagena new species Fig. 1
Material examined. Hero: 712-8 (one juvenile (paratype, USNM 234617)), 712-668 (one female (paratype, USNM 234618)), 715-874 (one male (holotype, USNM 234615), one male, two females, one juvenile, (paratypes, USNM 234616)).
Distribution. This species is known from off Peninsula Mitre, Tierra del Fuego, Argentina, in 135-137 m, and also in two localities on the nearby Isla de Los Estados in 23 m and along the shore.
Diagnosis. Trunk ovoid, lateral processes contiguous, with small paired dorsodistal tubercles, cephalic segment with similar anterolateral tubercles. Chelifores conventional. Palp 8-segmented, distal segments not ventrally serrate. Proboscis flask-shaped, inflated proximally, slender and tapering distally. Legs with scattered short setae rows, dorsodistal setae shorter than segment diameters, first coxae with four lateral setose tubercles, third coxae of third, fourth legs with long coxal spur equal to segment diameter, femoral cement gland tube on dorsodistal tubercle with adjacent spinose tubercle. Second tibia longest, tarsus with single stout ventral spine, several setae, propodus long, with four spines on low heel, several tiny sole spines. Auxiliary claws approximately half main claw length.
Description. Size moderately small; leg span 13.8 mm. Trunk compact, ovoid, lateral processes contiguous, armed with paired dorsodistal tubercles each bearing distal seta, posterior tubercle larger than anterior one, similar tubercles at corners of cephalic segment. Ocular tubercle tall, over twice longer than median diameter, with apical blunt tubercle, eyes large, of equal size, darkly pigmented. Abdomen elevated obliquely, distally tapering, armed with 2 paired dorsal setae not as long as segment diameter.
Proboscis flask-shaped, swollen proximally, abruptly tapering distally to half diameter of swollen part, slightly downcurved, lips rounded.
Chelifores typical, chelae atrophied to rounded bulbs with distal knob, scapes with 3 short dorsal and distal spines, the dorsodistal spine on small tubercle. Palps 8-segmented, without serrate distal segments, with setae increasing in number ventrally on distal segments.
Ovigers conventional, segments 3 and 5 subequal, slightly shorter than fourth. Strigilis segment 6 with stout, broad, proximal spine and few short lateral setae. Seventh, eighth, and ninth segments with single endal denticulate spine smaller than paired tenth segment spines.
Legs moderately slender, with few setae mostly in rows, none longer than its segment diameter. Tibia 2 the longest segment with tibia 1 slightly longer than femur. Cement gland tube short, at tip of bifurcate dorsodistal tubercle which has short seta-bearing tubercle adjacent. First coxae with 4 slender lateral tubercles each with distal setae, the posterodistal tubercle sometimes bifurcate with seta at each point. Male second coxae of posterior 2 leg pairs with long ventrodistal genital spur as long as segment diameter, bearing short distal setae. Tarsus short, with single stout ventral spine and several setae. Propodus long, moderately slender, with low heel bearing 4 spines increasing in size distally from the last. Sole with very small setae, claw robust, almost half propodal length, auxiliaries approximately half main claw length.
Measurements of holotype (in millimeters). Trunk length, 1.25; trunk width (across second lateral process), 1.09; proboscis length, 0.95; abdomen length, 0.59; fourth leg, coxa 1, 0.41; coxa 2, 0.48; coxa 3, 0.36; femur 1.26; tibia 1, 1.29; tibia 2, 1.31; tarsus, 0.14; propodus, 0.75; claw, 0.37.
Etymology. The name proposed for this new species (Latin: lagena, a flagon or flask) refers to the flask- or bottle-shaped proboscis.
Remarks. This species appears superficially to resemble many other Achelia, at least those of the southern hemisphere, except for the differences in its proboscis. The other known Achelia species, also in the southern hemisphere, have a proboscis which is proximally bulbous and distally tapering and downturned are A. transfuga Stock, 1954, and A. transfugoides Stock, 1973. These two closely related species are more like a species of Tanystylum, lacking as they do any form of chelae, but they have an extra palp segment and long denticulate strigilis spines which are more in keeping with species of Achelia.
The flask-shaped proboscis of this species is unique in a genus where the proboscis is almost always in the shape of a long teardrop with its widest point just before the midpoint. The widest point of this proboscis is at the bulbous proximal swelling well before the midpoint. From this proximal bulb the proboscis tapers gradually to a typical narrow tip, but the tapered part turns down in a definitive curve. As far as I have been able to determine, this proboscis shape does not occur in any other species in the genus.” (Child 1994, p.7-9)