Parapallene elongata, 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 : 15-18

Parapallene elongata sp. nov.

Figure 6a–j. Plate 6a–f u r n:lsid:z o oba n k.org:a ct:4F3A48C 0 -2C E F- 4 4E 0 -8D19-

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Material examined. Holotype. Female ( SAMA E9454 ). 5 km., west of Port Noarlunga, 27 m., J. Ottaway, 28 Mar 1980.

Diagnosis. Habitus slender. Neck long. Eye tubercle conical. Lateral processes widely spaced, with narrow, inconspicuous dorsodistal rim. Longer segments of legs without processes or

Figure 6. Parapallene elongata sp. nov., female, holotype (SAMA E9454): a, b, trunk dorsal and lateral; c, proboscis and chelae, ventral; d, right chela; e, detached leg; f, propodus, leg 2; g, right oviger (inner); h, segment 4, (outer); i, segments 7–10; j, segment 10 and terminal claw.

Plate 6. Parapallene elongata sp. nov., female, holotype ( SAMA E9454 ): a–c, trunk; dorsal, lateral and ventral; d, proboscis and chelae ventral; e, detached leg; f, propodus .

tubercles. Propodus almost straight, two strong heel spines, sole spines sparse, many leg spines serrated, auxiliary claws absent.

Description. Holotype, female. Leg span about 25 mm. Trunk segmented,slender,elongate(fig.6a, plate6a), cephalondistinctly shorter than remainder of trunk, single minute dorsal spine on third trunk segment. Proboscis sits within a pronounced cuticular rim on the anterior-ventral margin of the cephalon (fig. 6c, plate 6d.), base of proboscis and neck minutely papillose ventrally (plate 6d), each neck papilla with minute apical seta, neck length about 2.5 times basal width, no proximal cuticular division or fold is seen in dorsal view. Lateral processes 2 and 3 separated by about 3.5 times basal width, length almost 3 times basal width, each with inconspicuous, dorsodistal rim bearing several tiny setae, rim raised to a tiny central point (plate 6b). Faint lateral cuticular line extends length of lateral processes and along lateral margins of trunk.

Eye tubercle taller than basal width, apical half conical, pointed in lateral view, bifurcate when viewed from anterior; four eyes of equal size, lenses convex, lateral sense organs conspicuous, positioned at base of conical part and above eyes (plate 6b).

Proboscis short, inserted obliquely into cephalon, distally trilobate, each lobe bearing several tiny setae.

Chelifore scape without protuberances or tubercles, strong notch on outer proximal edge, best seen ventrally (fig. 6c, plate 6d), 3–4 strong seta on inner margin and several smaller dorsodistal setae; chela palm with many setae, fingers smooth, moveable finger closing to outside.

Oviger ten segmented (fig. 6g –i), segment 4 longest, with strong dorsolateral cone on outer surface, at about one-third length (fig. 6h), segment 5 next longest, segment 6 with one, strong, simple spine and one lesser spine on distal inner margin and another more proximal spine. Terminal claw with about seven teeth on distal half. Oviger strigilis spines simple, spine formula, segments 7–10, 9:7:5:5.

Anal tubercle almost vertical, length about twice width, without spines, uniformly inflated throughout length, rounded distally, gaping at tip, unsegmented at base.

Legs (fig. 6e, plate 6b, e). Coxa 1 with two, long, distolateral spines, coxa 2 almost three times length of coxa 1, widest distally, with strong mediolateral spines; femur slightly longer than tibia 1, ventral surface irregular, with three spine-tipped swellings, femur and tibia 1 without dorsodistal tubercle, tibia 1 with two long, fine dorsal setae and one shorter dorsodistal seta, tibia 2 longest segment, many dorsal spines on distal two-thirds, most larger spines on femur and tibiae serrated, propodus hardly curved (fig. 6f), with 2 to 3 heel spines, distal-most spine largest, serrated, 3 to 7 sole spines, variably serrated, claw slender, auxiliary claws absent. Gonopores large, ventral, coxa 2 all legs.

Measurements of holotype (mm). Trunk length (frontal margin of cephalic segment to tip of fourth lateral processes), 5.25; width across second lateral processes, 1.82; proboscis length (ventral), 1.31; length of scape 0.59; anal tubercle length, 0.49. Oviger: seg. 1, 0.16; seg. 2, 0.19: seg. 3, 04; seg. 4, 1.05; seg. 5, 0.82; seg. 6, 0.63; seg. 7, 0.35; seg. 8, 0.31; seg. 9, 0.26; seg. 10, 0.21; claw. 0.313. Third leg: coxa 1, 0.41; coxa 2, 1.17; coxa 3, 0.55; femur, 2.69; tibia 1, 2.31; tibia 2, 3.47; tarsus, 0.18; propodus, 0.84; claw, 0.53.

Etymology. The specific name relates to the attenuated habitus of the specimen and widely spaced lateral processes.

Remarks. There are four superficially similar species of Parapallene that share an elongated neck, the absence of auxiliary claws, and the absence of prominent processes or tubercles on the lateral processes and legs. These species are P. algoae Barnard 1946 South Africa, P. longipes Calman, 1938 , East and South Africa, P. australiensis ( Hoek, 1881) southern and eastern Australia, and P. hospitalis Loman, 1908 Java Sea, Indonesia. None of those species share the simple oviger strigilis spines with these specimens. Geographically this species is closest to P. australiensis from which it can otherwise be distinguished by the more widely-spaced lateral processes (segments 2 and 3 separated by 3.5-times width, versus about 2-times in P. australiensis ), cephalon distinctly shorter than remainder of trunk (versus aslong in P. australiensis ) and a longer neck (3.5 times base width, versus 2-times in P. australiensis ).

Complete illustrations and measurements of the trunk and legs of Parapallene algoae have never been provided to enable direct comparison with that species. Both P. algoae and P. longipes are known from southern Africa and the ovigers share a total of 67 finely serrated and lanceolate spines. In his key, Stock (1991) recorded the neck length of P. longipes as 6-times the basal diameter but based on Calman’s figure of the P. longipes holotype ( Calman 1938, Fig. 5A), the length of the neck is 4 to 5 times the basal width; much the same as P. algoae . The only differences seem to be in the proportions of the femur and first tibia. According to Barnard (1954: 112) the first tibia of P. algoae is distinctly shorter than the femur, whereas the first tibia and femur of P. longipes are subequal ( Calman, 1938:156). Based on the figures provided by Barnard (1954, Fig.12) and Calman (1938: Fig 5A) there appears to be a significant difference in the lengths of the necks, otherwise, in the absence of a complete description of P. algoae , there is very little to justify the independent status of these species. Stock (1956) noted the lack of a fold of the exoskeleton at the base of the neck in P. algoae as a further difference, but this collar has almost certainly been induced after collection of the specimen.

Staples (2014b) noted that P. hospitalis is probably misplaced in this genus. Parapallene hospitalis differs significantly from the other species being compared here by having a distally rounded proboscis, an immoveable chela finger terminating in a strong tooth and a “ Pallenella - type ” oviger claw with short teeth on both margins. Parapallene hospitalis can be further distinguished by compound oviger spines and possession of cement glands on the femur and first tibia.

Using Stock’s (1991) key to the genus Parapallene , this proposed new species can be followed down to couplet 9 where it keys out with P. famelica Flynn, 1929 (non-Clark, 1963) but from which it can most readily be distinguished by the simple oviger spines and the absence of prominent dorsodistal tubercles on the femur and first tibia.