Colossendeis australis Hodgson 1907

“Colossendeis australis

(Plate IX., fig. 1; Plate X., figs. 1 and 2.)

Specific characters: --

Body stout, with lateral processes widely separated, minutely scabrous, the spines being arranged in distinct rows on the appendages.

Proboscis enormous, bottle-shaped, more than half as long again as the body. Eyes, four, well developed.

Palp 10-jointed, the eighth and ninth joints equal, the tenth longer.

Claw of legs less than half the length of the propodus.

Under a lense the entire animal exhibits a beautifully mottled appearance, which, to a greater or less extent, appears to be characteristic of the genus. The Body shows the faintest traces of segmentation; the cephalon is short and only very little expanded, and the first pair of lateral processes is placed close against it.

The Ocular tubercle is situated in the middle of this area and is stout, with four well-developed eyes, two anterior and two posterior, the latter smaller than the others.

The Proboscis is of much greater diameter than the body, to which it is movably articulated; throughout the greater part of its length it is curved downwards; the mouth is very large. The organ is covered with minute spines, which seem to have, to some extent at least, an indistinct linear arrangement; the difficulty of making out their precise arrangement is accentuated by a growth of polyzoa.

The Abdomen is of moderate dimensions and somewhat claveate.

The ten-jointed Palp arises ventro-laterally, as close as possible to the proboscis. The two first joints are very short, and the third is rather more than twice the length of the fifth; the fourth is small; the sixth is barely one-third the length of the fifth, and the seventh is about half as long again as its predecessor; the eighth and ninth are shorter and sub-equal; the terminal one is absent from one side and injured on the other, but in the other specimen available it is a little longer. The lateral line appears along the greater part of the appendage. The entire limb is spinose, beginning with the third joint, and the minute spines are arranged longitudinally in rows as far as the end of the fifth joint, which, with the two preceding, bears a more or less complete whorl of spines at its distal extremity. Beyond the fifth joint the spines become stiff setae rather than spines; they are larger and more abundant and irregular, besides being aggregated on the ventral and inner side in the natural position of the limb.

The Ovigers are very long and, as characteristic of the genus, 10-jointed (fig. 1a). They arise from a small body-process immediately behind the palps, but nearer the middle line. The first three joints are small, the fourth and sixth are the longest and sub-equal, the fifth being about a quarter their size. The last four are sub-equal, and the appendage terminates in a small claw. The lateral line is distinctly marked. The entire limb is spinous. A few minute spines exist on the first three joints, beyond these they are arranged more or less clearly in lines and are more numerous. There is also a fringe of small spines on the outer margin of the distal extremity of each joint, but these are either inconspicuous or absent on the four terminal joints. With regard to the characteristic groups of spines on the four terminal joints, there are four rows on the three proximal joints and three only on the terminal joint. In both specimens the spines are so much worn as to give but a feeble idea of their true character (Plate X., figs. 1 and 2). The large size of the sockets in which they are planted is remarkable. The most ventral row, that which lies nearest the sea bottom in the natural position of the animal, comprises a small number, less than a dozen, of large stout spines. The second row, which in this species is not separated from the first by any conspicuous interval, contains approximately double the number of smaller spines; the sockets of this row are sometimes crowded together, and the spines are smallest and most crowded at the proximal end of the joint, and there are also deflected from a straight line by the articulation of the succeeding joint. Two other rows follow, but these have not the mathematical regularity of the former, nor are they so much deflected; they are reduced in number, but not in size. In structure the large spines appear to consist of a stout base almost circular in section and composed of a strong chitinous investment having a protoplasmic core; the spine tapers to a blunt point much worn, but with enough left to indicate a flattened blade at the extremity.

The Leg attains a length of 115 mm. The three coxae may be regarded as sub-equal in size, and short. The two tibiae are the longest joints and sub-equal, except in the first leg, where the second tibia is a trifle shorter than the first. The femur is a little shorter, and the tarsus less than half the length of any o f the three preceding joints; the propodus is just over half the length of the tarsus. On the first coxa there is dorsally and ventrally a median line of reddish colour, which appears to indicate the presence of a slight groove. On the second coxa the lateral line begins on each side of the joint, and passes to the extremity of the limb. The three coxae are minutely scabrous and possess a small fringe of minute spines at their distal margins. The remaining joints are more or less covered with these fine spines, which become a little more conspicuous as the extremity of the appendage is reached, which become a little more conspicuous as the extremity of the appendage is reached. Six rows are fairly well defined throughout the limb, a median dorsal, a median ventral, and two lateral, one on each side the so-called lateral line. The distal extremity of each joint bears a fringe of spines on the inside of the bend, largest and most conspicuous on the second tibia. The terminal claw is small, less than half the length of the propodus.

The Genital apertures occur on the second coxa of all the legs in both sexes, as shown in figs. 1b and 1c.

The above description has been prepared from an example taken in deep water. Another from shallow water presents certain differences: first, it is more spinose, especially the proboscis and the limbs; on the legs four additional irregular rows of spines may be distinguished between the six described for the deep-water specimen, two of these are dorsal and two ventral: and secondly, in the comparative length of certain joints. The third joint of the palp is distinctly less than twice the length of the fifth, and the fourth joint of the ovigerous leg is a little longer than the sixth.

The nearest ally of this species seems to be C. proboscidea, Sabine, form which, however, it may be instantly recognised by the wider intervals between the lateral processes and the presence of well-developed eyes.

Two specimens of this species were taken, one off Cape Wadworth, Coulman Island, 8-15 fm.; bottom: stones; the second off Mounts Erebus and Terror, 500 fm.; bottom: stones.

This latter specimen is the carrier of some half-dozen cirripedes of the genus Scalpellum.” (Hodgson 1907, p. 59-61)

Colossendeis australis ist eine Art der Asselspinnen (Pycnogonida). Sie lebt in den Gewässern um die Antarktis und der Antarktischen Halbinsel, den Südlichen Shetlandinseln, den Südsandwichinseln, Südgeorgien, den Falklandinseln, den Kerguelen, Neuseeland sowie den pazifischen und atlantischen Meeresbecken vor Chile und Argentinien in Tiefen von 15 bis 3.935 Metern.