Meridionale ambigua (Stock, 1956)

Staples, David A., 2014, A revision of the callipallenid genus Pseudopallene Wilson, 1878 (Pycnogonida, Callipallenidae), Zootaxa 3765 (4), pp. 339-359 : 350-351

Meridionale ambigua (Stock, 1956)

Figures 3 F–H

Pseudopallene ambigua Stock, 1956a

Remarks. The holotype of M. ambigua has been studied previously by the author ( Staples, 2005) and can now be compared to the holotype of M. laevis . Stock did not compare his specimen with M. laevis ; a decision no doubt based on his understanding that the scape segments in M. laevis were two-segmented. Instead he compared his species to the less similar M. pachychiera with which it shared the one-segmented scapes.

Only one oviger claw now accompanies the M. ambigua holotype and the blunt serrations on the remaining claw are consistent with wear and tear. In all other specimens of M. ambigua examined in this review the oviger claw is consistently long and narrow with an acute tip. The characteristics of M. ambigua can be summarized as follows: The immoveable finger is strongly curved, the chitinous margin is variably developed, darker and thicker in some specimens than in others. The chitinous cutting edge of both fingers is smooth and the edges of both fingers run almost parallel with each other for almost two-thirds of their length, the cutting edge of the moveable finger is preceded by a low, variably developed node or chitinous thickening on the inner dorso-lateral margin ( Fig 3 H). A median cuticular division is restricted to the frontal margin of the cephalon; the lengths of the lateral processes are a little less than twice the basal diameter. In the holotype the proboscis is widest at about mid-length with vague constrictions at about one-third and two-thirds its length. In all other specimens examined the proboscis only has a vague constriction at about half its length. The arthrodial membrane at the base of proboscis is wide ( Fig 3 F) allowing partial extension and retraction of the proboscis. The oviger claw is slightly less than half the length of segment 10. The oviger spine formula of the holotype is 15:9:10:10. Coxa 2>three times length of coxa 1 and the propodal heel commonly has three spines. Stock’s (1956) observation of a ‘corona of fine hair around the mouth’ is not evident in the specimens examined. It is possible that Stock may have confused residual food or detritus around the mouth with setae.

The live colour of M. ambigua is predominantly yellow.

A photograph of mating specimens (probably M. ambigua ) is reproduced here (from Staples, 1981) to show the male chelifores grasping the female in the region of the proximal chelifore scape constriction ( Fig. 4 A).

Distribution. Bass Strait, Tasmania and Victoria.

Figures

FIGURE 3. Meridionale laevis; holotype, (BMNH 1881.38), 1 female, A, trunk dorsal view; B, left chela; C, leg 3; D, propodus, leg 3; E, proboscis and left chela, ventral view. Meridionale ambigua; male holotype (ZMH K 17680); F, anterior view; G, trunk, dorsal view; H, right chela (scale bar = 1 mm.).

FIGURE 4. Meridionale ambigua (probably); A, mating pair (male on top). Meridionale harrisi; B, J 46800, anterior view; C, J 53273, right chela. Cordylochele longicollis; D, trunk dorsal view; E, propodus; F, oviger claw. Parapallene hospitalis; (USNM 78569), G, trunk, dorsal view; H, distal oviger segments.