Planipapillus absonus, Douch & Reid, 2023

Douch, James K. & Reid, Amanda L., 2023, A new species of Planipapillus (Onychophora: Peripatopsidae) that defies the original concept of its genus, Memoirs of Museum Victoria (Mem. Mus. Vic.) 82, pp. 257-262 : 258-261

Planipapillus absonus sp. nov.

https://zoobank.org/NomenclaturalActs/CE8B797D-A435-4F76-

A4F5-3677B5EF2055

Figures 1 –3

Material examined. Holotype 1♂, Victoria, Mount Useful Natural Features and Scenic Reserve , 14.5 km N of intersection of Binns Rd & McEvoys Tk, 37° 43’ S, 146° 31’ E, 1108 m, 3 Apr 1999, coll. A. Reid and R. Roberts ( MV K7279 ) . Paratypes 1♂ 4♀, data as for holotype ( MV K7280 ) .

Diagnosis. Body with pale longitudinal mid-dorsal stripe, punctuated by pale transverse stripes dorsal to each leg pair. Dark blotches present at each stripe intersection. Antennal rings banded. Without ovoid patch of reduced papillae on head of males or females. Anterior accessory glands and gland papillae present. Posterior accessory glands straight.

Description. Measurements. HWE males 0.77–0.81– 0.84 mm (n = 2, holotype 0.84 mm HWE); HWE females 0.90–1.13– 1.31 mm (n = 4).

Colour pattern. Ground colour caerulean (fig. 1a), olivaceous, or pale yellow with evenly scattered black papillae (fig. 1b–d). Pale, mid-dorsal longitudinal stripe extends posteriorly from base of head along length of body, with pale, transverse stripes and dark blotches dorsal to each leg pair along dorsal midline (fig. 1a, b). Legs paler than dorsum, with pale patches at junction with feet. Papillae around anal opening pigmented as for rest of ventrum. Ventral pigment ivory white (fig. 1c). Spinous pads pale yellow or pale olivaceous. Integument between genital and anal openings pigmented as for rest of ventrum.

Antennal rings. Antennal rings banded dorsally, varying between ground colour and slightly darker than ground colour (fig. 1a–d). Distal 7–9 antennal rings with sensory bulbs; sensory pads with one row of sensilla.

Eyes. EDI males 0.07–0.08– 0.08 mm (n = 2, holotype 0.08 EDI); EDI females 0.07– 0.07–0.08 mm (n = 4).

Head (males). No modification of head papillae (fig. 1b, d).

Head (females). No modification of head papillae.

Dorsal integument. Males with 11–11.5–12 (n = 2, holotype 11), females with 12.0–14.8–17.0 (n = 4) papillae counted from mid-dorsal line to junction of leg 10. Primary papillae dome-shaped (fig. 1e), approximately equidistant, interspersed by at least one secondary papilla (fig. 1f).

Male reproductive tract. Male genital pad cylindrical, protuberant. Proximal vasa efferentia separate, do not lie parallel before fusing to form vas deferens; vas deferens projects anteriorly before looping posteriorly to gonopore.

Male glands and gland papillae. Crural papillae on ventral side of legs 2–8 and 11–14. Papillae shape differs among legs: semicircular or cylindrical proximally, tapered abruptly to narrower, semicircular or cylindrical distal section (legs 2–8; fig. 1g) or subconical, low, not divided into distinct basal and distal regions (legs 11–14). Crural glands straight, elongate, not folded (fig. 2). Anterior accessory glands and gland papillae present. Posterior accessory glands curved, bulbous, blunt distally (fig. 2).

Female crural papillae. Absent.

Legs. Two relatively short claws. Nephridiopores intersect third spinous pad on ventral side of legs 4 and 5 (fig. 1h), openings broad U-shaped with smooth distal margin (fig. 1h, i).

Etymology. The specific epithet absonus, Latin for “discordant”, refers to the lack of reduced head papillae posterior to the eyes in males of this species, controverting what was previously thought to be a consistent and defining feature of the genus Planipapillus .

Distribution. This species is known only from the type locality (fig. 3).

Habitat. Under log in montane damp forest, with canopy dominated by species of Eucalyptus L’Hér.

Figure 3. Map of eastern Victoria and south-eastern New South Wales, Australia, indicating the type locality of Planipapillus absonus sp. nov. (*) among the type localities of all nominal congeneric species (z).

Remarks. This species is referred to as P. sp. 5 by Rockman et al. (2001), who demonstrated its membership in the genus Planipapillus via analysis of COI, 12S, and Ftz nucleotide sequences (GenBank accession numbers AF337991, AF338008, and AF338028, respectively). The authors state that “DNA preparation and scanning electron microscopy (SEM) are destructive, but wherever possible voucher specimens of both sexes were lodged at the Australian Museum in Sydney”. DNA preparation would not have required the destruction of an entire individual, and no electron micrographs of P. sp. 5 are presented in the article. Despite this, no specimens from which the aforementioned sequences were obtained could be located in the Australian Museum.

Figures

Figure 1. Planipapillus absonus sp. nov.: a, dorsolateral view in natura, ©David Paul; b, dorsal view; c, ventral view; d, anteriodorsal view; e, primary papilla; f, secondary papilla; g, crural papilla, leg 6; h, leg 5; i, nephridiopore, leg 5. b–d, stacked stereomicrographs, holotype ♂ 0.84 mm HWE (MV K7279), scale bars = 1 mm; e–i, scanning electron micrographs, paratypes MV K7280, scale bars = 30 µm; e, f, h, I, ♀ 1.04 mm HWE; g, ♂ 0.77 mm HWE.