Pseudopallene flava, Arango, Claudia P. & Brenneis, Georg, 2013

Arango, Claudia P. & Brenneis, Georg, 2013, New species of Australian Pseudopallene (Pycnogonida: Callipallenidae) based on live colouration, morphology and DNA, Zootaxa 3616 (5), pp. 401-436 : 426-428

Pseudopallene flava sp. nov.

Figs. 2 D, 3A, 14A–H

Material examined: Holotype (J4520): 1 male (PSE1), Nov-21 2009, Eaglehawk Neck, Tasmania , 5–20 m depth, on Orthoscuticella spp. Paratypes (S92301): 1 sub-adult (PSE1a), 1 male (PSE1b), same location as holotype, other material from same location: ( S92302 ) 3 males, 3 females, 2 sub-adults, 1 male (GBTAS), Oct-25 2008, Waterfall Bay, Eaglehawk Neck, 20 m depth, on bryozoans.

Diagnosis: Large size, 40 mm leg span, glabrous, plain yellow, straight inflated proboscis narrowing just distally. Legs with no constrictions, shallow propodal heel, six heel spines, middle one largest. Terminal claw crenulated on both sides, ventral longitudinal groove distally. Sequence divergence from 8 to 14 % in COI and 3 to 23 % in ITS ( Table 2 ).

Description of male: Leg span 40 mm, uniformly yellow-coloured when live ( Fig. 2 D). Body (Fig. 14B,D) fully segmented, glabrous, smooth; lateral processes as long as wide; neck (Fig. 14A,B) short, pre-ocular surface smooth, indistinct longitudinal cuticular division line, no mid-dorsal mound. Ocular tubercle short (Fig. 14A,B), as tall as wide, with a pair of small dorsal papillae, four darkly pigmented eyes of equal size. Abdomen (Fig. 14B) horizontal, not swollen, reaching distal margin of fourth lateral processes.

Proboscis (Fig. 14A) inflated, ending in a small narrow tip, without mid-point constriction.

Cheliphore (Fig. 14A–C) scape long, unconstricted, smooth, slightly longer than proboscis; chela longer than scape, palm inflated, fingers shorter than palm, of equal length; movable finger slightly curved, with small midpoint bump on cutting edge; wide gap when fingers touch at tip.

FIGURE 14. Pseudopallene flava sp. nov., male holotype (J4520) A, frontal view; B, lateral view. Note absence of mid-dorsal cephalic mound; C, detail of chelae, ventral view, distal oviger articles at the bottom; D, dorsal view, some legs in complete view; E–F, female paratype ( S92302 ); E, third leg; F, propodus and terminal claw of third walking leg; G, distal oviger articles including terminal claw; H, oviger articles 4 to 10, male distal apophysis visible on 5th article. Scale bars on stereomicroscopic images = 1 mm or as shown.

Oviger’s (Fig. 14G,H) fifth article longest, slightly curved, with distal apophysis, two-thirds of article diameter; four distal-most articles decrease in size distally; oviger compound spine formula: 20:12:12:10. Terminal oviger claw margins crenulated, crenulation along total length endally, along half its length ectally, longitudinally folded on ventral side forming a groove.

Leg (Fig. 14D–F) articles uniform in thickness, smooth, tiny spinules seen under high magnification; coxa 2 almost 2.5 times as long as coxa 1; femur curved, longer than tibia 1; tibia 2 longest article; tarsus short, with one large ventrodistal spine aligned with heel spines; propodus with protruding but not too prominent heel; four to five large, subequal heel spines; main claw length about 60 % of propodus length.

Measurements of male holotype male in mm: body length = 4.22; body width = 2.46; abdomen length= 0.59; ocular tubercle height = 0.27; proboscis length = 1.48; scape = 1.70; palm = 1.05; chela fingers = 0.80; oviger 5th article = 2.68, 10th article = 0.41, claw = 0.24; 3rd leg coxa 1 = 0.65, coxa 2 = 1.71, coxa 3 = 0.76, femur = 4.72, tibia 1 = 3.76, tibia 2 = 5.19, tarsus = 0.27, propodus = 0.90, claw = 0.57.

Etymology: The species epithet ‘flava’ means ‘yellow’ (latin, fem.) describing the bright, uniform yellow colouration of the specimens that contrasts with their dark orange-red bryozoan host.

Remarks: P. f l a v a is the largest species found in the Tasmanian material. Although similar in overall body size and colouration to P. ambigua , it differs strikingly from the latter in proboscis and especially chela shape. Owing to the lack of a mid-point constriction of the proboscis, even the smaller sub-adult specimens of P. f l a v a can be easily distinguished from the slightly smaller sympatric P. constricta , which is also uniformly yellow in life. Compared to P. f l a v a, the Tasmanian specimens of the Pseudopallene ‘variabilis’ -complex (see next paragraph) are significantly smaller and of more slender appearance. Female specimens show a slight basal constriction of the cheliphore scape as in other callipallenid species (see Discussion).

Figures

FIGURE 2. Live colouration of some of the species of Pseudopallene and Stylopallene included in the study. A, fresh live bryozoans Orthoscuticella spp. with many Pseudopallene specimens; B, P. constricta sp. nov., male in ventral view with egg masses attached to the ovigers; C, P. ‘ variabilis’ - complex, frontal-ventral view, note black tips of proboscis and chela fingers; D, P. flava sp. nov. in its natural habitat; E, Close-up of P. brevicephala male characterized by uniform orange-red body and legs, bearing orange eggs and transparent post-embryonic stages; F, P. pachycheira attached to bryozoan, showing banding pattern and constrictions of long leg articles; G, P. h a r r i s i sp. nov. in its natural habitat showing red-and-yellow colouration; H, specimen from the P. ‘ variabilis’ - complex with yellow-and-red colouration attached to live bryozoan; I, Stylopallene cheilorhynchus showing characteristic live black-and-creamy-white banding, photograph taken in captivity. All specimens from Eaglehawk Neck, Tasmania except 2 G and 2 H collected at Bass point, New South Wales.