Pseudopallene
Creators: name: Arango, Claudia P.
name: Brenneis, Georg
Publisher: name: Zenodo
Year: 2013
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Pycnogonida
Pantopoda
Callipallenidae
Pseudopallene

description: Pseudopallene ‘variabilis’ -complex
Figs. 2 C,H, 3C, 15A– O
Material examined (S92303): 1 female (PSE3), 1 male (PSE3a), 1 female (PSE3b), Nov-21–24 2009, Fog Rock, Eaglehawk Neck, Tasmania, 5–20 m depth, on Orthoscuticella sp.; (S9224): 2 post-embryonic stages (TAS17, TAS30a), 26 Jan 2007, Fortescue Bay, Eaglehawk Neck, Tasmania, 21 m depth, in kelp forest; (S92306): 1 male (AM122), 1 female, May-9 2003, Pope's eye, Portsea, Victoria, 8 m depth, on Amathia sp.; (S92474): 1 female, 1 male (SHE001), Nov-26 2010, Devils Cave, Bass Point, New South Wales, 15 m depth, on bryozoans; 1 sub-adult (SHE006), Nov-26 2010, Loose Rock, Bass Point, New South Wales, 20 m depth, on bryozoans.
Diagnosis: Legs with no constrictions, femora slightly curved; three or four large heel spines gradually increasing in length from proximal to distal, followed by a smaller pair; proboscis narrowing at two thirds length showing a variable degree of rough, scabby cuticle with dark marks at the distal portion in the Victorian and Tasmanian material; chela fingers short with straight cutting edges, in some specimens somewhat irregular, movable finger slightly shorter, fingers similarly pigmented as distal proboscis portion. The specimens proposed in the complex have a molecular divergence>8 % in COI and>3 % ITS sequence distance from other congeneric species for which these DNA fragments are available.
Description: Leg span around 20 mm, but up to 40 mm, predominantly yellow body colouration when alive, specimens from Tasmania either uniformly yellow or with some red marks on body and legs, specimen from Victoria with some red marks on body and legs, specimens from New South Wales with red marks on dorsum and concentric bands on legs (Fig. 2 H). Body (Fig. 15 B,C,G,H,L,M) fully segmented, smooth cuticle. Neck (Fig. 15 B,G,L) distinct, low mid-dorsal mound on pre-ocular surface in some specimens from Tasmania, no mound evident in specimens from Victoria and New South Wales, no distinct longitudinal cuticular division line. Lateral processes (Fig. 15 C,H,M) 1.5–1.7 times longer than wide, glabrous. Abdomen (Fig. 15 C,H,M) horizontal, inflated, overreaching fourth lateral processes except in specimens from New South Wales. Ocular tubercle (Fig. 15 A,C,F,H,K,M) as wide as tall, with distinct dorsal papillae, two pairs of darkly pigmented eyes of equal size.
Proboscis (Fig. 15 A,F,L) bullet-shaped, inflated most of its length then tapering towards two thirds of its length, distal section of rough appearance, scabby, with dark stain or ‘burn’ on the cuticle of Tasmanian and Victorian specimens.
Cheliphore (Fig. 15 A,F,K) scape long, glabrous, slightly longer than proboscis, unconstricted in males, with clear proximal constriction in females; palm short, inflated, fingers shorter than palm, at least by half.
Oviger (Fig. 15 E,J, O) fifth article with distal apophysis in males, with compound spine formula 14:8:6:8 (Tasmania) varying to 16:13:11:11 (New South Wales) and 16:12:12:10 (Victoria). Terminal oviger claw serrated on both sides, longer endal serration, in Tasmanian specimens with 12 sharp, deep denticulations, other material with 16 shallow, blunt crenulations. Femur slightly curved; only spare, tiny spinules on tibiae. Three to four large proximal propodal heel spines gradually increasing in length, longest about half of the diameter of propodus, distally followed by one pair of smaller spines (Fig. 15 D,I,N).
Measurements of PSE3a (male from Tasmania) in mm: body length = 2.55; body width = 1.59; abdomen length = 0.53; ocular tubercle height = 0.29; proboscis length = 1.16; chela fingers= 0.46; scape = 1.43; oviger 5th article = 0.61, 10th article = 0.22, claw = 0.17; 3rd leg coxa 1 = 0.5, coxa 2 = 0.66, coxa 3 = 0.53, femur = 2.5, tibia 1 = 2.04, tibia 2 = 3.24, tarsus = 0.21, propodus = 0.79, claw = 0.40.
Remarks: Owing to considerable overlap in morphological characters and very low genetic distances of the molecular markers used, we are unable to unequivocally discriminate species within this grouping of Pseudopallene forms and therefore have opted for a preliminary summary of these individuals in the ‘variabilis’ -complex. The low sequence divergence values encountered between these specimens compared to the other, in part sympatrically occurring Pseudopallene species (Table 2) are all the more remarkable for the ‘variabilis’ -complex material’s origin from three distant geographic locations. The relatively low distance values in COI and ITS sequences and their monophyletic grouping in the MP analysis (Fig. 6) indicate close relationships of these forms. At the morphological level, the chelae, proboscis and propodus characters show high similarity and set these specimens aside from the rest of the Pseudopallene material investigated in this study. However, other morphological characters, such as body size, ovigeral compound spine count and the pre-ocular mid-dorsal mound are variable between the three geographic forms of this complex. The middorsal pre-ocular mound of some Tasmanian specimens (Fig. 15 A) is to a certain degree reminiscent of P. inflata Staples, 2005 described from the Althorpe Islands, South Australia. Yet, the latter species is diagnosed based on a high dorsal mound with a clear longitudinal cuticular division line at the front, a characteristic that is not found in this material, and also the name-giving inflated body segments of P. inflata are not found in our samples.
There is also morphological similarity to P. c h e v ro n Staples, 2007,described from South Australia, some of our individuals resembling it in size as well as proboscis, cheliphore and propodus characteristics. But none of our specimens showed the described characteristic V-shaped dorsal trunk markings, which are said to persist after preservation (Staples 2007). Also the overall pattern of red markings on live P. chevron (shown in Gowlett-Holmes 2008) does not correspond to the patterns observed on our material, some of the Tasmanian specimens being even plain yellow. At the moment, hypotheses of species identities within the ‘variablis’ -complex need further testing with more specimens (including unequivocally identified P. inflata and P. chevron material) and possibly fasterevolving genetic markers.
description: Published as part of Arango, Claudia P. & Brenneis, Georg, 2013, New species of Australian Pseudopallene (Pycnogonida: Callipallenidae) based on live colouration, morphology and DNA, pp. 401-436 in Zootaxa 3616 (5) on pages 428-430, DOI: 10.11646/zootaxa.3616.5.1, http://zenodo.org/record/220125