Pallenella georgia, Staples, 2025

Staples, David A., 2025, Pycnogonids, ‘ sea-spiders’ (Arthropoda, Pycnogonida) selected from the collections of the South Australian Museum with descriptions of new species and review of the genus Pallenella., Memoirs of Museum Victoria 84, pp. 1-47 : 20-22

Key to species of Pallenella

Group 1 Anal tubercle horizontal. Chela palm more or less oval shaped, outer surface inflated, fingers, orientated forward in line with palm, moderately slender, outer margins gently and evenly curved, tapering to blunt tips, length immoveable finger>1.5 times width at base. Cephalon pre-ocular mound never prominent, longitudinal cuticular division of cephalon present or absent. Heel well-developed or low, spines linear or grouped.

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– Propodal heel well-developed, 4–10 primary spines grouped or linear. Oviger spine count 27–41 2

Propodal heel low, 3–4 primary spines linear, increasing in size distally, followed by smaller pair. Oviger spine count 45–54 6

2. Propodal heel, spines grouped, 7–10 primary spines, propodal sole curved, diverging at transition of heel to propodal sole. Cephalon longitudinal cuticular division present or not present 3

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3 Propodal heel spines linear, 3–6 primary spines, sole diverging sharply or weakly at base of heel lobe on chela moveable finger present or absent 4

Cephalon longitudinal cuticular division present, distinct.

Chela cutting edges uneven, few gaps showing when fingers closed. Oviger spine count 27–29. Propodal heel sloping into sole, 7–10 primary spines, several secondary spines. Live colouring uniformly red, orange

P. brevicephala ( Staples, 2008) – Cephalon longitudinal cuticular division absent 5

4 Chela moveable finger cutting edge with mid-point lobe. Oviger spine count 37. Leg surface smooth; propodus length almost 5-times maximum width, heel prominent, spines grouped, random, propodal claw slender, equally curved both margins. Proboscis with dorsal swellings at about one-third and two-thirds length of swollen part, distal-most swelling strongly inflated dorsally due to blister-like bubble before narrowing to a lengthy terminal part. (8 eye lenses) P. difficile ( Arango, 2009)

– Chela moveable finger cutting edge without lobe or irregularities. Oviger spine count 38. Leg surface irregular, undulate, propodal heel spines arranged in ‘V’ pattern, first spine longest, claw length about 3.5 times maximum width, inner margin almost straight, curved at tip only, outer margin inflated, evenly curved. Margins of proboscis proximal part almost parallel, very slightly inflated. (8 eye lenses) P. reflexa ( Stock, 1968)

5 Propodal heel with 4 primary spines, sole almost straight,

diverging sharply from heel, claw length about 3.5-times maximum width, outer margin inflated, inner margin almost straight, curved at tip only. Proboscis with marked constriction distal to mid-point, swollen distally before tapering to tip. Chela finger margins smooth, cutting edges, separated by narrow gap for most of length. Oviger spine count 30. Live colouring uniformly bright yellow

P. constricta ( Arango and Brenneis, 2013)

– Propodal heel with about 6 primary spines, sole weakly curved, divergence from base of heel weak, claw length about 5-times maximum width, slender, curved outer margin slightly inflated. Proboscis without constrictions, slightly dilating distally before tapering to tip. Chela fingers touching at tips only, cutting edges mostly smooth, but slightly raised in proximal half of moveable finger. Oviger spine count 41. (8 eye lenses).

P. georgia sp. nov.

6 Chela moveable finger cutting edge with small mid-point bump. Oviger spine count 54, claw longitudinally folded, narrow at tip. Proboscis inflated, bullet-shaped, without constrictions. Propodus compact, length about 2.5-times width, heel 4 primary spines plus distal pair of short, side-by-side spines, first spine short, fourth primary spine longest, sole diverging at base of heel, claw outer margin inflated, inner margin almost straight, tip curved, pointed. Preocular longitudinal division line may be indistinct. Leg span about 40 mm. Live colouring yellow

P. flava ( Arango and Brenneis, 2013)

– Chela moveable finger cutting edge smooth or with small bump. Oviger spine count 45–49, claw with rounded tip, scoop-shaped. Proboscis slender, bullet-shaped, without constrictions. Propodus length 3.5–4.0-times width, sole divergence from heel slight. Leg span, 27–30 mm 7 7

– Smaller distal-most paired heel spines arranged linearly. Chela moveable finger cutting edges smooth, without irregularities. Oviger spine count 45. Live colouring predominantly yellow/orange with conspicuous red chevrons on the trunk dorsal surface

P. chevron ( Staples, 2007)

Smaller distal-most heel spines paired. Chela moveable finger with small protruding bump half way along cutting edge. Oviger spine count 49. Live colouring yellow, body markings absent P. baroni Brenneis et al., (2020)

Group 2. Anal tubercle horizontal. Chela palm conspicuously bulbous, fingers robust, short, length of immoveable finger <1.5 times width at base, almost straight, with low dorsal swelling; moveable finger outer edge strongly curved, typically with a distinct elbow-like bend at about one-third length, hook-like. Cephalon pre-ocular mound low or distinctly elevated, (but not acute), with or without longitudinal cuticular division. Propodal heel low or prominent.

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5 Femur and tibiae each divided by two conspicuous constrictions. Oviger spine count 27. Live colouring orange, brown but perhaps variable. (4 eye lenses)

P. pachycheira ( Haswell, 1885)

Femur and tibiae without constrictions, or irregularities 2

Pre-ocular surface evenly rounded, inflated or bulbous, longitudinal cuticular division absent. Propodal heel raised, graduating into sole or prominent and isolated, ~12 grouped spines, sole diverging at transition of heel to propodal sole 3

Pre-ocular surface distinctly elevated or low, longitudinal cuticular division present. Propodal heel low, 2–5 linear spines, sole weaky curved 4

Propodal heel raised, distal surface graduating into sole. Pre-ocular surface inflated, evenly rounded. Oviger spine count 45. Propodal claw slender, both margins curved equally. (8 eye lenses) P. brenneisi sp. nov.

Propodal heel prominent, isolated from sole by absence of intermediate spines. Pre-ocular surface bulbous. Oviger spine count 63. Propodal claw outer surface rounded, inflated, inner surface almost straight, only curved distally. (8 eye lenses) P. octolentium sp. nov.

Pre-ocular surface distinctly elevated 4–5 heel spines 5

Pre-ocular surface low, evenly rounded, 2–4 heel spines 6

Chela moveable finger with evenly curved outer margin, immoveable finger particularly short, strongly rounded, both fingers with rounded tips, cutting edges with opposing lobes and indentations, no conspicuous gaps showing when closed, immoveable finger very short, strongly rounded. Oviger spine count 44. Propodal claw slender, both margins equally curved. 4–5 heel spines. (8 eye lenses) P. watsonae ( Staples, 2008) 6 Moveable finger with mid-point lobe on cutting edge, proximal gap present when fingers closed. Pre-ocular surface distinctly elevated, 3-4 primary heel spines. Oviger spine count 51. Propodal claw outer margin inflated, inner margin straight, curved only at tip. Live colouring: trunk red with yellow lateral processes, leg segments two shades of red with distal bright yellow distal bands P. harrisi ( Arango and Brenneis, 2013)

– Pre-ocular surface low, evenly rounded. Chela moveable finger with low lobe on cutting edge, proximal gap between fingers when closed. 2–3 primary heel spines. Propodal claw slender, both margins equally curved. Cuticular longitudinal division of cephalon present but perhaps restricted to anterior margin 7

7 Length of lateral processes about 1.7 times basal width. Oviger spine count ~ 54. Male coxa 2 almost three times length coxa1, propodus curved, claw with both margins curved similarly. (8 eye lenses) P. smithi sp. nov.

– Length of lateral processes about 1.4 times basal width. Oviger spine count ~ 44. Male coxa 2, 2.2 times length coxa 1, propodus almost straight, claw with outer margin slightly inflated, more rounded than inner surface. (4 eye lenses P. ambigua ( Stock, 1956)

Group 3. Anal tubercle inclined. Chela immoveable finger almost in line with palm, pointed at tip, moveable finger evenly curved. Elevation of cephalon pre-ocular surface absent, longitudinal cuticular division absent. Legs smooth, tiny setae present but without spinules, propodal heel low or prominent, primary spines arranged linearly, sole diverging or not diverging at base of heel.

1 Propodal heel low, sole almost straight, not diverging from base of heel, claw broad, outer margin conspicuously inflated, inner margin almost straight, curved at tip only. Cephalon pre-ocular mound absent. Chela fingers about half length of palm, palm elongate 2