Acrophylla alta, Coupland & Emmott, 2025

Coupland, Ross M. & Emmott, Angus J., 2025, A new giant species of Acrophylla Gray, 1835 (Phasmida: Phasmatidae: Phasmatini) from the highlands of the Wet Tropics, Queensland, Australia., Zootaxa 5647 (4), pp. 371-383 : 374-381

publication ID	https://doi.org/10.11646/zootaxa.5647.4.4
publication LSID	lsid:zoobank.org:pub:40007489-896D-4F0C-BBFE-B9A61D64AAC1
DOI	https://doi.org/10.5281/zenodo.15920421
persistent identifier	https://treatment.plazi.org/id/03D72B1D-4F56-543C-FF7D-6702FAF2FA19
treatment provided by	Plazi
scientific name	Acrophylla alta
status	sp. nov.

Treatment

Acrophylla alta sp. nov.

[Highlands Giant Acrophylla ]

( Figs. 2–4 View FIGURE 2 View FIGURE 3 View FIGURE 4 )

Holotype ♀, AUSTRALIA, Queensland, Millaa Millaa , 17°31’13”S 145°34’01”E, 19.xi.2024, R. M. Coupland, 1090m a.s.l. ( QM; Registration number: T261445 ). GoogleMaps

Paratype ♀, AUSTRALIA, Queensland, Upper Barron , 17°25’58”S 145°30’47”E, 09.ii.2025, P. van Oosterzee, N. Preece, A.J. Emmott, 1020m a.s.l. ( QM; Registration number: T261446 ) GoogleMaps .

Description. Very large, spinose stick-insect of generally light brown colouration featuring prominent light to emerald-green ventrolateral surfaces to the abdomen and mesonotum. Conspicuous white patch on lateral edge of forewings adjacent to base of metafemora. Faint mottling present on dorsal surfaces of forewings and pre-anal portion of hindwing. Prominent, dense spination on mesonotum, mesotibiae and metatibiae. Profemora heavily serrate tending to flanged on protibiae and tarsi. Conspicuous, lateral flanges present on mesotibiae and metatibiae. Cerci elongate with dull serrations ( Fig. 5A, B View FIGURE 5 ).

♀ ( Fig. 3 View FIGURE 3 ). Head: smooth, slightly longer than wide. Three ocelli present but not prominent. Eyes subtly mottled light brown/green with faint, broken longitudinal, light cream bands.Antennae thin, about same length as profemora, 26 segments, basal segment longer and wider than segment 2.

Thorax: Pronotum slightly longer than head, width similar, with subtle sculpturing on dorsal surface featuring randomly-spaced, small tubercles. Mesonotum, pronotum and head of uniform, light brown colouration. No spines present on underside of pronotum. Mesonotum approx. 4× length of pronotum with densely-spaced, pronounced spines on all surfaces ( Fig. 5C, D View FIGURE 5 ). Two thin, lateral lines of light green consistent with lateral abdominal colouration, running length of mesonotum, interspaced with a thicker, spinose line of light brown. Ventral surface of mesonotum and metanotum also densely spinose.

Abdomen: Smooth and lightly mottled with indistinct patterning on dorsal surface tending to blotching along lateral edges. Ventrolateral portions of abdominal segments 1–7 featuring striking green colouration ( Figs 2 View FIGURE 2 , 6A View FIGURE 6 & 7A View FIGURE 7 ). Different individuals may exhibit a lighter to emerald-green, possibly influenced by age or environmental factors. Colouration of ventral apex surfaces largely consistent with that of dorsal surface. Segments 5 and 6 slightly laterally lobed. Segments 7–9 shorter, smooth and uniform in colour. Segment 9 and anal segment roughly equal in length ( Fig. 5B View FIGURE 5 ). Operculum large, boat-shaped and tapered to pointed tip, reaching beyond end of anal segment ( Fig 5A View FIGURE 5 ).

Cerci: Long, similar length to abdominal segments 8–10. Indistinctly shaped, being both dorsally and laterally compressed along length with dull serrations on edges from mid to tips ( Figs. 5A, B View FIGURE 5 ).

Wings: Forewings approximately 0.5x length of hindwings ( Fig. 3B View FIGURE 3 ). Colouration of hindwing dorsal surfaces slightly lighter brown than mesonotum, femora etc and featuring subtle, mottled patterning overlayed with darker venations. Conspicuous white mark on lower edge of forewings adjacent to metafemora. This mark is somewhat triangular and rounded in shape, but the feature may vary in other individuals, as noted with other species within the genus, such as Acrophylla titan ( MacLeay, 1826) and A. cookorum (Brock, P.D. & Coupland, R.M., 2022) . Base of pre-anal portion of hindwing featuring distinct, dark brown patterning, not visible when at rest. Entire ventral surface of pre-anal portion also distinctly mottled in dark brown. Hindwings tessellated, black to light brown, lighter brown at edges with tessellated venations across entire surface ( Figs. 3B View FIGURE 3 , 7B View FIGURE 7 ). Several small, light brown accents equally spaced along outer edge of hindwings.

Legs: Profemora very long, robust and flanged with large serrations on outermost edges. Inner edges smooth, consistent with largely smooth protibiae. Slightly laterally lobed on distal-facing protarsal segments ( Fig. 6C View FIGURE 6 ). Metafemora, mesofemora and associated tibiae heavily spinose with dark spines on outer edges, tending to lighter spines on inner edges. Conspicuous, single lateral lobe present on lower, outer carina of both metatibiae and mesotibiae ( Fig. 6B, D View FIGURE 6 ). This feature is unique among the known Australian Acrophylla sp ..

Measurements [mm]: For holotype female (first), then paratype female. Note: paratype missing left foreleg. Length of body: 255, 260. Head: 11.5, 15.5. Antennae: 54, 54. Pronotum: 12.5, 12.3. Mesonotum: 48, 48.5. Metanotum: 20, 20.4. Forewing: 59.3 x 20.5, 60 x 17. Pre-anal portion of hindwing: 124.5 x 15.4, 122.7 x 17.4. Alae: 124.5 x 69.2, 118 x 70. Profemora: 63.3, 63. Mesofemora: 50, 52.5. Metafemora: 55.3, 59.7. Protibiae: 60.6, 68. Mesotibiae: 48.7, 51. Metatibiae: 55.8, 62.5. Cerci: 19, 20.3. Total length with prolegs outstretched: 410, 425 ( Figs. 3A, B View FIGURE 3 . & 7A, B View FIGURE 7 ). Unladen weight taken for paratype when alive, 34g. Another female individual examined (but not collected) (Rennee and Wayne Young pers. comm. February 2025) measured 275mm from head to tip of cerci, total length including profemora 410mm. This individual weighed an impressive 44g unladen weight ( Fig. 10 View FIGURE 10 ). These measurements would suggest that A. alta sp. nov. may be the heaviest known insect in Australia, surpassing the Giant Burrowing Cockroach, Macropanesthia rhinoceros ( Saussure, 1895) , (Matsumoto, T., 1992). For comparison, a mature female of the large Goliath Stick-insect, Clemacantha goliath ( Gray, 1834) plump with eggs, was found to weigh 21g (Sarah and Lewis Silvio pers. comm. March 2025).

Note. Colour and spine density appear to be somewhat variable characters within this species. It may be the case that older specimens exhibit darker green accents on the abdominal dorsolateral margins and are of darker brown colouration overall. Examination of specimens in future studies would help to clarify the degree of variation found within the species.

Differential diagnosis. The following notes are important to consider when comparing morphologically similar adult females of species within the genus Acrophylla . A. alta sp. nov. may appear superficially similar to A. titan , but features lobes on the mid and hind legs and more pronounced, dense spines on the forelegs and thoracic segments. The colouration also differs, with A. alta sp. nov. having conspicuous, green accents to the abdomen and lacking the stout, purple spines of A. titan . Note also that these two species occur at a significant geographic disparity (see table 1.). A. wuelfingi has similar colouration and size to A. alta sp. nov. and may occur concurrently at some locations, i.e. Danbulla, Qld. However, the mesonotum and legs are much less spinose in A. wuelfingi and the end of the abdomen (cerci and operculum) differ greatly in form and structure (see notes in table 1.). The egg morphology, if available, is also an important consideration when identifying species, with notable differences in the prominent features.

Egg. ( Fig. 4 View FIGURE 4 ) Pale cream colour with some light brown accents and greyish areas, featuring densely-spaced, shallow pitting on surfaces. Rounded base with slightly ovate sides and flat, circular, pitted operculum with prominent capitulum. Capitulum largely cylindrical, 1mm long and rounded at tip. Capitulum grey in colour at base, tending to orange/brown at middle with a greyish tip featuring some sculpturing. Large micropylar plate with much enlarged, rounded base portion, indented at apex. Edges of micropylar plate raised with well-defined ridge. Measurements: 5.8–6.1mm long, 3.8–4mm x 3.3–3.5mm wide.

Notes on male and sub-adult female individuals. So far, only a single image of what we believe constitutes a male of A. alta sp. nov. has been available for study ( Fig. 9 View FIGURE 9 ). The individual was observed at a location (Danbulla, Qld) where a likely sub-adult female was also photographed and uploaded to iNaturalist. Observations: https:// www.inaturalist.org/observations/254477430 and https://www.inaturalist.org/observations/253973769 respectively. Note: long cerci apparently present in both individuals, which differentiates them from A. wuelfingi , a species also known to occur in the area. From the angle of the photograph, the specific morphology of the cerci and other features cannot be clearly distinguished. The male appears to feature prominent dark mottling of the pre-anal portions of the hindwings and is of generally elongate, slender form. There are white edges to the forewings which is a common feature among male Acrophylla species. While apparently not particularly spinose, there are several low spines or tubercles on the mesonotum and the profemora appear somewhat serrate. There may also be a dark dorsal line along the length of the mesonotum; if so, an unusual feature, not known from other Acrophylla species. Future searches of suitable habitat may yield male(s) for study.

The sub-adult female’s general form is consistent with that of other species within the genus. That is, features such as spines and serrations are reduced but key characters remain, which are sufficient for identification to species level. There is more uniform colouration on sub-adult individuals than that found on adults and this is true of the insect in the observation, which appears to be of an overall brown/green colour. The apparent large size of the individual and developed form of the wing buds suggests it is approaching its final moult.

Etymology. Named on account of this species apparently occurring only in areas at high altitude with suitable habitat.

Distribution. So far only recorded from a handful of localities on the upland areas of the Wet Tropics Bioregion, Queensland. These locations include Mt Lewis National Park, Evelyn Tablelands (likely including the Maalan National Park), Topaz, Upper Barron, Mt Hypipamee and Danbulla.

Habitat and foodplants. Currently known to occur in areas featuring ‘Simple to complex notophyll vine forest of cloudy wet highlands on basalt’, Qld Government Regional Ecosystem ID’s 7.8.4 and 7.12.16. This species has been found feeding on Syzygium sp. cf. smithii, Myrtaceae , also noted on S. papyraceum , although may have been knocked from another tree as it was found on a low limb and in apparently poor condition, (Stephen Hey pers. comm. November 2024). Readily feeds on Guava, Psidium guajava , Mrytaceae in captivity. Likely to feed on other, local rainforest trees within suitable habitat types. In nature, A. alta sp. nov. is extremely well camouflaged despite the large mass of the females, the colouration and subtle patterning being well matched to the vegetation.