Comprehensive Description

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Description

Austropallene calmani n. sp. Figs. 12a; 13a-c and 14a.

 

 

Sta. 90. 2 females (including holotype), 1 young.

 

Sta. 100. 1 female (incomplete).

 

Sta. 105. 1 ovigerous male (total length = 3.5 mm.)

 

 

Description of holotype: This female which measure 4.3 mm. in total length, resembles A. tibicina in general build although the lateral processes are more widely separated (fig. 12 a). The cephalic somite is equal to the sum of the two succeeding segments; the neck is of medium length and the large cephalic lobes each bear a sharply pointed spur. The ocular tubercle is low and wide, and the eyes are conspicuous. The lateral processes are rather more than twice as long as wide and are separated distally by intervals exceeding their own diameter, The first process has only one, each of the others has a pair of distal spurs; in some cases there is also a minute tubercle midway between the two spurs. The first lateral process on the left, the second on the right, side have undergone regeneration together with the respective walking legs. The proboscis is rather longer than the cephalic somite, of almost uniform diameter throughout the greater part of its length and bluntly conical at the apex (fig. 12 a). In lateral aspect the distal part curves slightly downwards. The abdomen is short, directed almost perpetually upwards.

 

 

The chelophores are robust and rather massive in proportion to the rest of the animal. The scape which is three times as long as wide, is narrowed proximally and bears 2-3 stout spines (fig. 12 a). The chela is rather shorter than the scape; the fingers are sharply pointed and the movable one fits into a cavity, bounded by a ventral lobe, some distance from the apex of the immovable one.

 

 

The walking legs are longer and more slender than those of A. tibicina (cf. figs. 13a and 12c). The spurs on the first coxa are longer than those of the lateral processes. The second coxa is four times as long as wide (maximum width near distal end), and bears two pairs of spinose projections on the proximal half. The femur is rather more than six times as long as wide, and there are 4-6 small dermal papillae on the ventral margin. The first tibia is ten times as long as wide, with 8-9 dermal papillae on the dorsal, and 4 minute ones on the ventral margin. The second tibia, the longest segment, is fourteen times as long as wide, with 8-9 dermal papillae on the dorsal margin. The tarsus is approximately one-sixth, the claw two-thirds of the propodus (fig. 13 a).

 

 

There are minute developing ova in the femur of each leg, but the specimen has apparently spawned previously and the femur has reached its maximum width. The female paratype, on the other hand, has scarcely reached sexual maturity for, although there are fairly large developing ova, the femur is more slender than in the holotype.

 

                                                                                                                                
 

TABLE 3

 
 

Species

 
 

Austropallene brachyura

 
 

A. tibicina

 
 

A. calmani

 
 

A. gracilipes

 
 

Sex

 
 

Female

 
 

Male

 
 

Female (T.N. 338)+

 
 

Female paratype

 
 

Male holotype

 
 

Male young

 
 

Female holotype

 
 

Male paratype

 
 

Female paratype

 
 

Male holotype

 
 

Male paratype

 
 

Length in mm.

 
 

6.3

 
 

5.5

 
 

5.3

 
 

3.6

 
 

4.3

 
 

3.9

 
 

4.3

 
 

3.5

 
 

4.5

 
 

5

 
 

4.7

 
 

No. of leg measured

 
 

3

 
 

3

 
 

2

 
 

3

 
 

4

 
 

3

 
 

3

 
 

2

 
 

4

 
 

3

 
 

3

 
 

4

 
 

3 & 4

 
 

Length/breadth of : Second coxa

 
 

4

 
 

5

 
 

4.2

 
 

4

 
 

3.8

 
 

3

 
 

5.5

 
 

6

 
 

4

 
 

5.8

 
 

5.8

 
 

8

 
 

7.4

 
 

“ : Femur

 
 

7

 
 

11

 
 

7

 
 

6.8

 
 

6.8

 
 

5.5

 
 

8.5

 
 

12

 
 

6.4

 
 

8.8

 
 

11

 
 

15

 
 

14

 
 

“ : First tibia

 
 

9.5

 
 

9

 
 

8.3

 
 

8

 
 

7.8

 
 

7

 
 

7

 
 

11

 
 

10

 
 

7.5

 
 

15

 
 

18

 
 

13*

 
 

“ : Second tibia

 
 

14

 
 

14

 
 

11.8

 
 

11.8

 
 

12

 
 

10

 
 

12

 
 

16

 
 

14

 
 

12

 
 

22

 
 

-

 
 

20

 
 

+ “Terra Nova” Collection

 
 

* This segment is more expanded distally than in the holotype

 
 

 

 

The male is very similar to the female as regards the general build of the body. The walking legs are more slender proximally (see table 3) ; there are 10-12 minute dermal papillae on the ventral margin of the femur and 2-3 pairs of spines on the second coxa; the tibiae are rather stouter than those of the female (cf. fig. 13a and b). The oviger is represented in fig. 12 c; there are 10+9+9+9 special spinules on the terminal segments.

 

The immature specimen from Sta. 90 may safely be referred to this species since there is already one prominent spine on the scape of the chelophore, although the fingers have not as yet acquired the same shape as in the adult.

 

 

Remarks: This species can easily be distinguished from A. tibicina by several well-marked characters. (1) The proboscis is much less curved in lateral aspect and is contracted only near the apex (cf. fig. 12a and b). (2) The chelophores are much more robust, with spinose scape and the palm of the chela is higher than long; in A. tibicina the height is equal to the length, measured to the base of the movable finger. (3) The walking legs are less setose and those of the female are more slender (see table 3 and figs. 12 c and 13a), with fewer dermal papillae, especially in the femur.

 

 

Distribution: Off the Antarctic Continent, in the Gauss and Victoria Quadrants.” (Gordon 1944, p. 42-45)

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Creative Commons Attribution Non Commercial 3.0 (CC BY-NC 3.0)

© National Museum of Natural History, Smithsonian Institution

Source: Antarctic Invertebrates Website (NMNH)

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