Piona mutawintji, K & PešićK, 2025

Piona mutawintji n. sp.

Zoobank: CBFFE474-C7A7-4EB4-BA1E-62BCE7BE5164

Figures 3-4 View Figure 3 View Figure 4

Material examined — Holotype male, New South Wales, pools in Homestead Creek , Mutawintji NP, 31 Oct. 2001, leg. H. Smit, dissected and slide mounted ( AMS) . Paratypes: 3/3/0, same data as the holotype, one female dissected and slide mounted ( AMS), 3/2/0 (in fluid, RMNH). Other material. New South Wales. 1/1/0, rockpools, Mootwingee Gorge, Mutawintji

NP, 31-x-2001 ; 1/0/0, artificial pool, Rockholes Loop, Mutawintji NP, 31 Oct. 2001. South Australia. 1/1/0, Round Swamp, Bool Lagoon Game Reserve, 12 Oct. 2001.

Diagnosis — In both sexes a part of the acetabula is incorporated into a genital plate (male)

or into a platelet (female). Palp with strong sexual dimorphism in P4 (in male P4 stocky, ventrally expanded, in female P4 slender, ventrally not expanded), in both sexes P-4 distal peg-like seta separated from distal segment margin. Genital field with 13-15 pairs of acetabula in both sexes.

Description — Colour yellowish. Dorsum with one pair of sickle-shaped platelets. Apodemes of Cx-I relatively short, posterior extensions of Cx-IV large. Palp with strong sexual dimorphism in P4, distal peg-like seta of P4 separated from distal segment margin. Legs long and slender.

Male — Cx-IV medially separated. Genital plates fused with Cx-IV, not extending beyond posterior extension of Cx-IV, with 13–14 pairs of acetabula, most of acetabula lying free in the idiosoma, not on plates ( Figure 3 View Figure 3 A-B), gonopore short. 5-6 pairs of acetabula lying on a platelet fused with the gonopore. Excretory pore with a sclerotized ring, not fused with the genital plates, anteriorly to flanking glandularia. (vgl-5) P4 stocky, ventral tubercles large, the distal one with a peg-like seta ( Figure 3D View Figure 3 ). III-L-6 about the half of length of III-L-5, anterior claw (sensu Harvey 1996) strongly curved with ventral clawlet, posterior claw long and nearly straight ( Figure 4D View Figure 4 , inset). IV-L-4 modified with posterior concavity lined with several proximal and two distal peg-like setae ( Figure 4E View Figure 4 ).

Female — Cx-III/-IV widely separated medially ( Figure 3E View Figure 3 ). Genital field with two pairs of plates: small anterior platelets bearing one acetabulum and surrounded by several setae, posterior plates sickle-shaped, with 12-13 pairs of acetabula, two or three of them free in idiosoma ( Figure 3F View Figure 3 ). Palp as illustrated in Figure 4A, P4 View Figure 4 slender, ventral tubercles short, flanked by some small setae, distal peg-like seta separated from distal segment margin.

Measurements — Male (holotype, in parentheses some measurements of paratype).

Idiosoma dorsally 825 (838, n=1) long and 619 (625, n=1) wide; dorsal platelet 58 long. Coxal field 550 long (measured from Cx-I tip to pend of posterior extension of Cx-IV), Cx-III width 538. Genital field 323 wide between outer edges of genital acetabula; gonopore 47 long.

Ejaculatory complex 126 long.

Palp: dorsal length/height: P1, 34/58; P2, 150/88; P3, 72/61; P4, 147/47; P5, 53/28. Capitulum ventrally 147 long, 200 with apodemes. Chelicera 222 long, basal segment 172 long, claw 68 long. Dorsal lengths of I-leg-1-6: 66, 95, 135, 175, 206, 191; dorsal lengths of II-leg-1-6: 72, 108, 141, 200, 225, 203; dorsal lengths of III-leg-1-6: 88, 120, 155, 209, 228, 124; dorsal lengths of IV-leg-1-6: 131, 113, 150, 206, 238, 198; swimming setae numbers are as follows: I-leg-4, 3; I-leg-5, 5; II-leg-4, 4; II-leg-5, 6; III-leg-4, 1; III-leg-5, 6; IV-leg-4, 3; IV-leg-4, 4-5.

Female Idiosoma dorsally 1520 long and 1047 wide. Coxal field 606 long, Cx-III width 775, medial length Cx-III+IV 163. Genital field 397 wide between outer margins of genital plates; gonopore 194 long, pregenital sclerite 138 wide.

Palp: dorsal length/height: P1, 44/66; P2, 170/94; P3, 88/69; P4, 178/50; P5, 69/28 Gnathosoma ventrally 191 long, 225 with apodemes. Chelicera 331 long, basal segment 225 long, claw 88 long. Dorsal lengths of I-leg-4-6: 203, 247, 247; dorsal lengths of II-leg-2-6: 141, 184, 253, 271, 244; dorsal lengths of III-leg-2-6: 141, 191, 253, 281, 256; dorsal lengths of IV-leg-1-6: 150, 144, 222, 291, 313, 266; swimming setae numbers are as follows: I-leg-4,

4; I-leg-5, 6; II-leg-4, 5; II-leg-5, 7; III-leg-4, 8; III-leg-5, 9; IV-leg-4, 5-7; IV-leg-4, 6-7.

Etymology — Named after the Mutawintji National Park, the location of the type locality.

The name is a noun in apposition.

Remarks — Due to the similar structure of the genital field (in both sexes only some acetabula incorporated into genital plate) and palp (P-4 distal peg-like seta separated from distal segment margin) the new species resembles Piona murleyi Harvey, 1996, a species known in both sexes from Western Australia ( Harvey 1996). From the latter species, the new species from South New Wales can easily be separated by P4 stockier and ventrally expanded (compare figure 4D with figure 88 in Harvey 1996), and the number of acetabula is much lower in P. murleyi, especially those acetabula not lying on the platelet fused with the gonopore (3 in murleyi, 9 in the new species).

Distribution — New South Wales, South Australia.