Micropathus ditto Beasley-Hall, 2025

Micropathus ditto Beasley-Hall sp. nov.

urn:lsid:zoobank.org:act:

Figs 1–2 View Fig View Fig , 5–6 View Fig View Fig , Table 1

Diagnosis

The hind femora are entirely unarmed and lack both apical and linear spines, the only known member of Micropathus with this configuration. The male suranal plate is rounded at the proximal margin and emarginate distally, forming two rounded lobes, unlike M. tasmaniensis and M. kiernani ( Figs 2 View Fig , 6b View Fig ). The male subgenital plate is triangular distally with a pronounced, rounded apex ( Fig. 6c View Fig ). The female suranal plate is triangular proximally and faintly emarginate distally ( Fig. 6d View Fig ). The female subgenital plate bears two lobes originating from its medial surface rather than the distal margin, further distinguishing the species from its close relatives. These lobes are separated at the bases by a distinct medial groove and remain in contact throughout their length ( Figs 6e View Fig ).

Etymology

Named after, a Pokémon from the video game franchise of the same name. Ditto has the unique ability to transform into an exact replica of other Pokémon and mimic their physical appearance. To us, this trait is reminiscent of M. ditto Beasley-Hall sp. nov. effectively hiding in plain sight: the species has been known to science for over sixty years, but until the present study it was considered a southern population of M. tasmaniensis . As a result, M. ditto has already been the subject of diverse studies concerning phylogenetic relationships, feeding habits, and chromosome numbers, but under an incorrect name ( Richards 1968; Eberhard 2001; Allegrucci et al. 2010; Richardson et al. 2013; Beasley-Hall et al. 2018; Allegrucci & Sbordoni 2019). This confusion was caused by the species sharing very similar morphology. Indeed, Richards’ description of M. tasmaniensis erroneously included an illustration of M. ditto (see redescription of the former below). The species name ‘ditto’ is not a Latin or latinised word and we therefore treat it as indeclinable in compliance with ICZN Article 31.2.3 (ICZN 1999).

Type material

Holotype

AUSTRALIA – Tasmania • ♂; Precipitous Bluff, Damper Cave ( PB1 ); 43.482° S, 146.59° E; 152 m a.s.l.; 3 Feb. 2023; S.M. Eberhard leg.; GenBank: PV368136 ( COI); TMAG F156341 View Materials ; TMAG. GoogleMaps

Paratypes

AUSTRALIA – Tasmania • 2 ♀♀; same data as for holotype; TMAG F156342 View Materials to F156343 View Materials ; TMAG GoogleMaps • 1 ♂; same data as for holotype; TMAG F156342 View Materials ; TMAG GoogleMaps • 1 ♀; same data as for holotype; ANIC 14- 008973 About ANIC ; ANIC GoogleMaps • 1 ♂; same data as for holotype; ANIC 14-008974 About ANIC ; ANIC GoogleMaps .

Other material examined

TASMANIA – Hastings Caves State Reserve • 1 ♂; near Platypus Walk; 43.413° S, 146.87° E; 23 Dec. 2018; M. Van Dyke leg.; photograph; iNaturalist 37292098. – Ida Bay • 3 ♀♀; Big Tree Pot Cave (IB-009); 43.463° S, 146.85° E; 211 m a.s.l.; 28 Sep. 2011; R. Eberhard leg.; valley entrance to cave; GenBank: PV368135 ( COI); TMAG F156345 to F156347; TMAG • 1 ♂; same data as for preceding; TMAG F073198; TMAG • 1 spec.; Exit Cave; 43.476° S, 146.839° E; 119 m a.s.l.; 23 Feb. 2011; S.M. Eberhard leg.; molecular data only; GenBank: PV197427 ( 12S rRNA); SARFMEE 12:0954. – Lune River • 1 ♀; unnamed cave; 43.445° S, 146.82° E; 551 m a.s.l.; 11 Aug. 2024; C. Fitzgerald leg.; photograph; iNaturalist 235051418 • 1 ♀; Lune River environs; 43.465° S, 146.87° E; elev. 225 m; 14 Dec. 2021; S. Grove leg.; photograph; iNaturalist 103213443. – Mystery Creek Cave • 2 ♂♂; 43.462° S, 146.85° E; 139–160 m a.s.l.; 21 Dec. 2023; J. Thurman leg.; photograph; iNaturalist 195459143, 195459145 • 1 ♀; same data as for preceding; 170 m a.s.l.; 13 Mar. 2021; T. Rudman leg.; photograph; iNaturalist 71119620 • 1 nymph; same data as for preceding; elev. 146 m; 26 Jun. 2024; B. Bell leg.; photograph; iNaturalist 225296767 • 1 ♀, 1 ♂; same data as for preceding; 151 m a.s.l.; 4 Feb. 2023; M. Van Schilt leg.; photograph; iNaturalist 148003491 • 3 ♀♀, 4 ♂♂, 3 nymphs; same data as for preceding; 177 m a.s.l.; 9 Dec. 2015; S. Grove leg.; photograph; iNaturalist 9359209. – Pindars Peak • 1 spec.; Morning Light Cave ( PP 1); 43.543° S, 146.67° E; 305 m a.s.l.; 24 Nov. 2011; S.M. Eberhard leg.; molecular data only; GenBank: PV197429 ( 12S rRNA); SARFMEE 12:0618; SARFMEE.

Description

MEASUREMENTS. ♂ body length 14–15 mm. ♀ body length 14–16 mm, ovipositor 11–12.5 mm. Hind tibia 23–25 mm; sexual dimorphism absent.

HEAD. Light brown and mottled with mid brown patterning on vertex and frons. Fastigium divided into two tubercles with a pale ocelliform spot on either side. Medial ocellus present.

BODY. Generally mid brown mottled with pale brown and ochreous patches particularly prominent on thoracic nota. Thoracic nota and abdominal sternites with row of pale brown flecks at distal margins. Thin medial line running down thoracic nota, not visible beyond metanotum.

LEGS. Ochreous brown with pale brown striations and patches concentrated proximally. Fore and middle legs as in generic diagnosis above, with ventral surface of tibiae bearing two rows of linear spines, one each prolaterally and retrolaterally, each containing 3–5 linear spines. Hind femur without apical or linear spines. Dorsal surface of hind tibia with 32–38 linear spines prolaterally and 28–32 retrolaterally. First segment of hind tarsus with 1–4 dorsal linear spines prolaterally and 1–3 retrolaterally. Second tarsal segment with 1–2 dorsal linear spines each prolaterally and retrolaterally.

MALE TERMINALIA. Suranal plate dark brown and densely setose except for proximomedially. Proximal margin of suranal plate rounded. Suranal plate straight laterally, becoming rounded distolaterally. Distal margin of suranal plate emarginate medially and curved ventrally, forming two wide, rounded lobes; underside of each lobe with a black, dentate fringe of tubercles which may be produced as thin spines. Sternite 9 with styles; proximomedially lacking setae and with a pale, V-shaped ridge; distal margin curved dorsally, subgenital plate originating underneath. Subgenital plate pale, without setae, and prominently triangular with rounded apex.

FEMALE TERMINALIA. Suranal plate mid brown and setose at distal margin but otherwise glabrous. Proximal margin of suranal plate broadly triangular and with rounded apex. Plate laterally convex, distal margin rounded and with a faint medial notch. Subgenital plate convex laterally with two long, narrow lobes produced from medial surface and separated by distinct medial groove, their length extending past distal margin and measuring over half that of plate; apices of lobes rounded. Basivalvulae present, bulbous, positioned lateromedially. Ovipositor light reddish brown. Ventral valve of ovipositor bearing 6–7 small, weakly produced teeth decreasing in size towards apex; each tooth often paired with sclerotised ridge on corresponding lateral surface.

Distribution

In limestone and dolomite caves of the Ida Bay, Precipitous Bluff, Pindars Peak, and Hastings karst areas in southern Tasmania, up to 500 m a.s.l. ( Fig. 1b View Fig ).

Remarks

Micropathus ditto Beasley-Hall sp. nov. was previously considered a southern population of M. tasmaniensis and is referred to as Micropathus “sp. nov. 2” in the phylogeny of Beasley-Hall et al. (2025). Its range notably includes caves at Ida Bay , a popular caving destination. In the past this karst area was subject to considerable cave fauna sampling, monitoring, and conservation studies driven in part by successive threats posed by native forest logging and limestone quarrying. As such, its life history and ecology – while still poorly known – may be slightly better studied than other Australian Rhaphidophoridae . Micropathus ditto co-occurs with cave-adapted glow-worms, beetles, spiders, and harvestmen ( Driessen 2009). The species is the main prey of the large, iconic Tasmanian cave spider Hickmania troglodytes ( Richards & Ollier 1976) . Eggs of M. ditto , laid in moist sediment banks, are also a key food source for troglobitic beetles at Ida Bay ( Driessen 2009) . Similar to the Rhaphidophoridae in the Northern Hemisphere, these surveys suggest Micropathus ditto is a keystone species due to their biomass and abundance in cave habitats.