Luzonogryllus (Apterozacla) appa Tan & Alo, sp. nov.

(Figs 1–5)

Material examined. Holotype: PHILIPPINES: Mindanao • ♂; Lanao del Norte, Iligan, Barangay Rogongon, Sitio Lagkong, with denser and older forest; N8.22158 E124.46417, 823.1± 6.2 m.a.s.l.; 6 October 2025, 09h56; on tree trunk near ground; coll. J.R.A. Alo; MIN.25.85 (PNM).

Allotype: • ♀; same locality and details as holotype; MIN.25.86 (ZRC).

Paratypes: PHILIPPINES: Mindanao • 2♀; Lanao del Norte, Iligan, Barangay Rogongon, Sitio Lagkong, along stream; N8.22260 E124.46358, 788.9± 8.6 m.a.s.l.; 4 October 2025; 19h17; under dead trunk; coll. M.K. Tan et al.; MIN.25.5, 6 • 1♂; Lanao del Norte, Iligan, Barangay Rogongon, Sitio Lagkong, denser and older forest; N8.22146 E124.46249, 815.3± 5.9 m.a.s.l.; 5 October 2025, 19h34; on mossy rock; coll. M.K. Tan et al.; MIN.25.50 • 1♀; Lanao del Norte, Iligan, Barangay Rogongon, Sitio Lagkong, with denser and older forest; N8.22158 E124.46417, 823.1± 6.2 m.a.s.l.; 6 October 2025, 09h56; on tree trunk near ground; coll. J.R.A. Alo; MIN.25.87 (all ZRC).

Diagnosis. The new species is characterised by the colour pattern (see below) and the large male genitalia with distinctly-shaped pseudepiphallic lophi and median sclerite.

The new species differs from Luzonogryllus (Apterozacla) mindoroensis Gorochov, 2006 from Mindoro Island and Visayas region (see below) by the dorsum of the head having a yellow band along margin of eye but this ring does not extend ventrad towards gena and mouthparts (instead of the ring along margin of eye only present at laterally and extend ventrad towards gena and mouthparts), scapes cream coloured with two black bands at the basal and distal ends (instead of mostly dark brown), white rings on antennae broader, the pronotum mostly black (instead of mostly yellow brown with black patterns), its frons with a ventrad-pointing arrow-shaped stripe (instead of a diamond-shaped yellow patch nearer to mouthparts). It also differs in by male genitalia being larger and distinctly differently shaped.

It also differs from Luzonogryllus (Squamizacla) palawanensis Gorochov, 2006 from Palawan and Borneo Islands by the presence of yellow band along margin of its eye not extending ventrad towards gena and mouthparts, frons with a ventrad-pointing arrow-shaped yellow band (instead of a straight vertical yellow band), the absence of wings in males and the shape of the genitalia (most easily differentiated by the shape of pseudepiphallic median sclerite).

Etymology. The species is named after the fictional sky bison, Appa, from the ‘Avatar The Last Airbender’ animated series. This is due to the resemblance of having a ventrad-pointing arrow-shaped stripe on their frons, pubescent and stripped body; noun in apposition.

Description. Habitus as shown in Figs 1, 2. Head dorsum finely pubescent, mostly black, sometimes with faint yellow longitudinal stripes; with yellow band along margin of eye (Figs 3A–C). Fastigium with two rows of setae, scapes twice as wide as fastigium (Figs 3A–C). Scapes black basally, with median cream-coloured ring, distally black (Figs 3D, 3E). Antennae mostly black with white rings of relative regular intervals, rings basal of antennae narrower (Fig. 2). Eyes in dorsal view rounded, protruding anteriorly (Figs 3A–C) and in profile view higher taller than long (Figs 3D, 3E). Median ocellus rounded, grey (Figs 3D, 3E); lateral ocelli rounded, located close to one another between hind of scapes (Figs 3B, 3C). Face in anterior view flat, shiny and oblong, ca. 1.1 times higher than wide; with medial yellow band running down from median ocellus to labrum, appearing like arrow pointing ventrad (Fig. 3D). Maxillary palpi grey to black, slender and elongated, with fine short setae; with apical segment longest, enlarged obliquely at apex; with subapical and third segments cylindrical; subapical segment shorter than third segment (Figs 3F, 3G). Gena shiny black, margin of eye yellow (Figs 3F, 3G). Pronotal disk mostly black, with marmoration of yellow or cream; very densely pubescent, setae golden; ca. 1.4 times wider than long; anterior margin straight, lateral margins slightly convex, posterior margin at middle broadly concave; anterior and posterior margins with a row of long yellow setae (Figs 3A, 3B). Pronotal lateral lobe ca. 1.4 times higher than long; mostly black, dorsal end with pale stripe irregularly sinuous; finely pubescent; anterior and posterior margins also with row of long yellow setae; ventral margin broadly rounded towards anterior and posterior margins (Figs 3F, 3G). TI lacking tympanum. TIII with 2 inner and 5 outer subapical spurs, 3 inner and 3 outer apical spurs; with numerous tiny spines proximal of first subapical spurs and between subapical spurs. FI and FII generally black with two or three cream-coloured rings, sometimes ring incomplete; sometimes ventrally cream coloured (Fig. 2). TI and TII generally black with three cream-coloured rings of increasing width distally (Fig. 2). FIII cream coloured; with numerous black spots, bands and rings; apical part including knee black (Fig. 2). TIII black with three incomplete cream-coloured rings (Fig. 2). Tergites black with marmoration of cream colour and yellow patterns; densely pubescent, setae golden yellow (Figs 2, 3A–C); sternite cream coloured.

Male. Apterous. Anal plate trapezoidal, transverse, basal half with yellow or cream-coloured patch, apical margin broadly rounded (Fig. 4A). Subgenital plate typical of genus.

Male genitalia (Fig. 5) stout, distinctly larger than congeners. Pseudepiphallic median sclerite obliquely situated; at middle forming two oblique triangular apical lobules with acute apices, narrowly emarginated between these apical lobules. Pseudepiphallic lophi long, somewhat separated into two parts: basal part surpassing apex of pseudepiphallic median sclerite in lateral view elongated triangular with obtuse apex, in dorsal view external of apical part; apical part strongly sclerotized, more slender and elongated, in dorsal view lamellar slightly curved medially, with inner margin undulated, apex very slender and subacute, in lateral view at apex slightly bent ventrad. Pseudepiphallic parameres oblong, inner margin very straight, elongated, surpassing pseudepiphallic median sclerite and basal part of pseudepiphallic lophi but not apical part of pseudepiphallic lophi; at apex in dorsal view narrow and obtuse, in lateral view somewhat triangularly acute. Ectophallic apodeme robust and stout, in ventral view, at posterior end forked into two stout and broad arms, anterior end forming less sclerotized broadly oval plate. Ectophallic fold very small. Endophallic sclerite small, shaft like.

Female. Not different from male, also apterous. Frons with arrow-shaped yellow vertical stripe less pronounced than in males, instead with pyriform yellow spot at middle of frons and vertical yellow stripe between antennal sockets (very finely connected) (Fig. 3E). Anal plate not different from male, basal half with two yellow or cream-coloured lateral spots (instead of transverse band in males). Ovipositor typical of genus, relatively long; at apex with ventral valves slender and distinctly surpassing dorsal valves; dorsal and ventral valves with margins generally smooth without denticles, with apices acute (Figs 4B, 4C).

Measurements. See Table 1.

Type locality. PHILIPPINES: Mindanao: Lanao de Norte.

Distribution. Known only from type locality.