Metallacantha aculeata Engelking, Ghirotto, Fianco, Sobral, Silva-Neto & Mendes, 2025

Metallacantha aculeata Engelking, Ghirotto, Fianco, Sobral, Silva-Neto & Mendes gen. et sp. nov.

urn:lsid:zoobank.org:act:B29475F3-2996-4B23-849C-A1955F8E2E29

Figs 1–21 View Fig View Fig View Fig View Fig View Fig View Fig View Fig View Fig View Fig , table 1

Diagnosis

As for the genus.

Etymology

From Latin aculeata , meaning “spiny” in reference to the many distinct spines of this katydid, especially the enlarged ones on its hind legs.

Type material

Holotype

BRAZIL – Bahia • ♂ ( Figs 2–4 View Fig View Fig View Fig , 17 View Fig ); Santa Teresinha, Pedra Branca district ; 12°50′41.6″ S, 39°29′28.6″ W; 10 Jul. 2024; P.W. Engelking and M. Fianco leg.; DZUP. GoogleMaps

Paratypes (7 specimens)

BRAZIL – Bahia • 1 ♀ ( Figs 10–14); Vitória da Conquista , near urban area; 14°53′47.6″ S, 40°51′55.5″ W; 13 Feb. 2023; S.P. Silva leg.; MZUSP GoogleMaps • 1 ♂ ( Figs 5–9 View Fig View Fig View Fig View Fig View Fig ); Caetité, CompleXo Uranífero de Lagoa Real ; 8–16 Jan. 2000; J.L. Nessimian and D.F. Baptista leg.; MNRJ • 1 ♀ ( Figs 15–16 View Fig View Fig ); Santa Teresinha, Pedra Branca district ; 12°50′ S, 39°30′ W; 430 m; 9 Feb. 2001; Jonas leg.; INPA GoogleMaps • 1 ♂, 1 ♀: Santa Teresinha, Pedra Branca district ; 12°50′41.6″ S, 39°29′28.6″ W; 10 Jul. 2024; P.W. Engelking and M. Fianco leg.; MZUSP GoogleMaps • 1 ♀, 1 ♂ nymph (nymph in Fig. 19 View Fig ); same data as for preceding; DZUP GoogleMaps .

Description

Male ( Figs 2–9 View Fig View Fig View Fig View Fig View Fig View Fig View Fig View Fig , 17 View Fig , 20–21 View Fig View Fig )

COLORATION ( Fig. 17 View Fig ). Description based on live specimens. General coloration light and dark green. Antennae, cerci, fore and mid tibiae terracotta pink. Palpi white. Eyes light brown. Two parallel stripes run from behind the eyes, passing through the lateral margins of the pronotum and on the thorax, right above the coxae I–III, ending right before the end of the coxae of hind legs. Superior stripe whitish and slightly wider, and the inferior stripe dark salmon to purplish, narrower, and matching the color of the ventral area of thorax and abdomen. Legs with green femora and hind tibia and light brown tarsi.

HEAD. Fastigium of verteX laterally flattened, with medial furrow ( Figs 3A View Fig , 5B View Fig ). Antennal orbit sclerites elevated, with bilobate apex, visible in dorsal and frontal view ( Fig. 3A View Fig ); eyes globular ( Fig. 3A View Fig ). Frons, clypeus, and genae slightly rugose. Frons straight, junction with genae divided by a vertical and straight keel, in frontal view. Clypeus quadrangular, labrum large and rounded, 1.3× longer than clypeus in frontal view. Scapus cylindrical and slightly tapering towards apex; pedicellus cylindrical, 0.65× shorter and narrower than scapus; antennal segments short, wide, with several short bristles gradually shorter towards the apex, making a velvet aspect; antennae length 7.1–7.6 cm, at least 5.8× longer than anterior femur. Lateral region of the head bearing a whitish band also running from behind the eyes and continuous with the inferior margin of lateral lobe. Withish region between inferior frons and superior clypeus. Pronotal disc anteriorly and laterally gently round, smooth, and posteriorly straight with a smooth medial projection in dorsal view ( Fig. 2B View Fig ); metazona moderately elevated, posterior margin elevated and with curved sides in lateral view ( Fig. 5B View Fig ). Pronotal disc 1.1× as wide as long anteriorly and 0.7× as wide as long posteriorly. Pronotal disc with lateral margins slightly elevated, with a whitish band running along the entire lateral edge. Pronotum, in dorsal view, slightly tapering towards the anterior portion in a slightly trapezoidal aspect. In lateral view, dorsolateral suture slender, straight, and further bearing a longitudinal suture dorsomedially ( Fig. 2B View Fig ). In dorsal and lateral views, furcal suture dorsomedially united and straight; laterally with bifurcated ramification anteriorly and posteriorly ( Fig. 2B View Fig ). Dorsolateral suture and furcal suture concolorous with pronotal disc ( Fig. 2B View Fig ). Probasisternum bearing two spines ( Fig. 5B View Fig ). Mesobasisternum subrectangular, anteriorly straight to slightly curving towards posterior portion, laterally slightly inwardly curved, posteriorly emarginate; bearing two posterocentral triangular acute projections ( Fig. 5C View Fig ). Metabasisternum elliptical, anteriorly straight to slightly curving and tapering towards posterior portion, posteriorly emarginated, and bearing two posterocentral triangular acute projections oriented hindward ( Fig. 5B–C View Fig ). Spines from pro to metabasisternum gradually increasing in size ( Fig. 5B–C View Fig ).

WINGS. Tegmina distally acuminated with apex round and gently inwardly curved in the anterior edge; posterior margin suboval, anterior margin slightly sinuous near apex ( Fig. 6 View Fig ). Tegmina showing numerous irregularly shaped, relatively small cells. Vein C weak, poorly curved, and bifurcated. Veins Sc and R parallel, very close to each other, almost straight at basal two-thirds; both strong and located on the medial region of tegmina, extending towards the tip. Vein Sc with two main bifurcations reaching margin of tegmina. Vein R with a single bifurcation near the apex that also bifurcated before contacting the margin. Vein M contiguous with MP strong and curved, MA weaker, sinuous, and bifurcated near the apex, one bifurcation merging with R and other with tegminal margin ( Figs 2C View Fig , 6 View Fig ; see also the similar female tegmina in Figs 12A View Fig , 16A View Fig ). Stridulatory area triangular, 0.7× as large as pronotum ( Figs 2B–E View Fig , 6 View Fig ); A1 sinuous, tapering towards the lateral region, file with delicate stridulatory teeth covering less than 10% of A1 width in the medial region similar to a zipper strip, with 87–105 wide, sharp and minute teeth ( Fig. 2E View Fig ); mirror elliptical to almost round, asymmetric at the sides with left anterior edge shorter than right anterior edge, and bearing an obtuse angle in the right lateral edge post-medially; scraper straight and sharp ( Figs 2C–E View Fig , 6 View Fig ). Membranous wing hyaline, triangular, reduced, unspotted, and with simplified venation, extending to two to three tergites ( Fig. 6A View Fig ).

LEGS. Robust and large in relation to the body ( Fig. 2 View Fig ), hind legs almost twice the length of the body ( Figs 2 View Fig , 5A View Fig ). Fore femur almost straight, mid femur very slightly downcurved ( Fig. 2 View Fig ). Tympanum present. All femora bearing rows of conical or triangular porrect spines, two dorsally and two ventrally – spines of the dorsal surfaces gradually shorter and becoming rounded, similar to mounds near the apex. Profemora with 6 spines on each ventral row and 11–12 on each dorsal row. Mesofemora with 7–8 spines on each ventral row and 11 on each dorsal row. Lateral carinae of all femora projected apically, forming triangular sharp spines. Pro and mesotibiae with basal third dorsoventrally widened, protibiae bearing tympanum at that widening, shown as a narrow slit ( Figs 2 View Fig , 5 View Fig ). Protibiae basally very slightly curved on the dorsal surface, dorsally without spines, ventrally, on apical half, with two sparse rows of thin, sharp, and porrect spines, two to three on each row. Mesotibiae slightly procurved, dorsally with a pair of large, almost straight, thin, and sharp spines on basal two-fifths, in one of the mid legs with a further single smaller spine more apically, pre-medially, located near posterior edge; ventrally with two rows with three spines similar to those of protibiae. Hind leg very thick. Metafemora slightly downcurved and very slightly recurved. Metafemora dorsally with two rows of slightly porrect conical spines stopping slightly before the apex, anterior row with 19–26 spines, posterior row with 19–22 spines; often with extra spines between rows near the apex ( Figs 2 View Fig , 5 View Fig ). Metafemora ventrally with two rows of slightly porrect spines, anterior row with 18–19 more triangular spines, posterior with 7–9 smaller spines distributed only on distal two-thirds ( Figs 2 View Fig , 5 View Fig ). Metatibiae slightly downcurved and extremely thorny ( Figs 2 View Fig , 5A View Fig , 7A View Fig ). Dorsally with an outer row of 7 slightly porrect, large, laterally flattened, and widened triangular spines with blackish and iridescent outer surfaces – the proximal three very large, the central one medium to small, and the distal three small and narrower, close to each other and near apex ( Figs 2 View Fig , 5A View Fig , 7A View Fig ). Dorsally with a further posterior row of 7–8 spines, the first four large, somewhat triangular, thorny, thin, long, and slightly sinuous (occasionally some are smaller), with some setae on the dorsal and medial region, apeX quite smooth and pointed ( Figs 2 View Fig , 5A View Fig , 7A View Fig ); the last four (or five in rows with eight spines) slightly porrect; the last three (or four in rows with eight spines) close to each other and near apex, pairing with those of the anterior row ( Figs 2 View Fig , 5A View Fig , 7A View Fig ). Ventrally with a single row of 12–13 spines on the anterior edge, all except the last thin, long and inwardly curving, those near apexes slightly porrect; first three smaller, gradually increasing in size towards posterior portion; the largest spines are those near the center of the tibiae; penultimate and antepenultimate spines smaller, decreasing in size towards posterior; last spine very porrect, straight, small, and conical, paired by a single spine on the posterior edge ( Figs 2 View Fig , 5A View Fig , 7A View Fig ).

ABDOMEN. Large, wide. Tergum X with posterior margin expanded and rounded ( Fig. 4A View Fig ). Subgenital plate rounded, anterior margin with a V-shaped depression, posterior margin slightly concave ( Fig. 4C View Fig , 7B View Fig ); lateral flange, styliform processes, and styli absent; cerci conical, at base 1.2× as wide as long ( Fig. 4 View Fig ).

GENITALIA ( Fig. 9 View Fig ). Membranous, dorsal lobe without titillator’s sclerites, composed of a slightly sclerotized round central lobe of rough surface more basally ( Fig. 9A View Fig ). Dorsal fold as an apical projection of 0.6x the length of the central lobe, basally with a central sulcus, apically further bifurcated into two short round lobes at the apex, those bearing several small dark sclerotized spines ( Fig. 9C View Fig ). Ventral lobe composed of symmetric upper and lower folds. Upper folds long, more than half the length of the genitalia, very similar to a cercus in which they are somewhat cylindrical, with a tapering apex and a widened base, further bearing several bristles from around half the length up to the apex ( Fig. 9B View Fig ). Lower folds as two wide and round lobes ( Fig. 9A View Fig ).

Female ( Figs 10–16, 18 View Fig )

COLORATION ( Fig. 18 View Fig ). Similar to the male, tegmina with or without a subquadrate dark brown spot on the anterior edge, below the main veins; ovipositor dark brown with blackish spots.

HEAD. Similar to the male, except: eyes slightly smaller; scapus and pedicellus slightly longer ( Fig. 11 View Fig ); antennae total length 9.5 cm, at least 5.8× longer than anterior femur ( Fig. 10).

THORAX. Similar to the male, eXcept wider. Pronotum significantly tapering towards anterior portion, trapezoidal in shape ( Figs 10, 11B–C View Fig ). Pronotal disc 1.1× wider than long; thoracic sternites wider due to a thicker thorax than that of males ( Figs 10, 12B View Fig ).

WINGS. Tegmina of females in the same shape as those of males ( Figs 12A View Fig , 16A View Fig ). Tegmina with cells smaller and veins more sinuous than those of males ( Figs 12A View Fig , 16A View Fig ). Tegmina with no modifications to sound production. Hind wings slightly smaller in comparison to those of males (but because the abdomen in females is much wider) and covering the same tergites as in males ( Figs 12C View Fig , 16B View Fig ).

LEGS. Similar to those of the male, except: hind legs 2× longer than body length (excluding ovipositor). Profemora with 6–7 spines on each ventral row and 9–10 on each dorsal row ( Fig. 10). Mesofemora with 7–8 spines on each ventral row, and 12–13 on dorsal rows ( Fig. 10). Protibiae ventrally on apical half with sparse rows of thin, sharp porrect spines, three on each row ( Fig. 10). Mesotibiae dorsally with a pair of large, almost straight, thin, and sharp spines on basal two-eighths ( Fig. 10).

ABDOMEN. Large, wide, like the thorax, overall thicker than that of male ( Fig. 10). Tergum X with posterior margin expanded and rounded ( Figs 14 View Fig , 15I–K View Fig ). Cerci conical, short, strongly tapering to an acuminate apex ( Figs 14 View Fig , 15I–K View Fig ). Subgenital plate trapezoidal, wider than long, and strongly indented into two triangular edges ( Figs 14B View Fig , 15J View Fig ). Ovipositor laterally flattened, long, curved, and with apeX widened in lateral view; apeX finely serrate, with several short and round projections dorsally, ventrally, and slightly laterodorsally and lateroventrally ( Fig. 14A–E View Fig ).

Nymph ( Fig. 19 View Fig )

Nymphs are fairly similar to adults, with several spines on their legs, including the characteristic widened iridescent metallic spines of foretibiae ( Fig. 19A View Fig ). Dorsally, the body is keeled mainly at the posterior areas of the thorax and the abdomen, making the mid-length of the katydid being projected, with tergum I as its highest point. Laterally, the abdomen also forms a keel on each side. The white lateral line is present, similar to that of adults, extending through all thorax, and, in addition, specimens bear further white lines at the anterior edge of tergum I bordering the thorax and on the lateral abdominal keels ( Fig. 19A View Fig ). In mid to later instars, nymphs exhibit raised wingbuds pointing upward, as in other Pterochrozinae ( Fig. 19B–C View Fig ).

Distribution ( Fig. 1 View Fig )

Known only from the State of Bahia in Brazil, in the municipalities of Anagé, Caetité, Santa Teresinha, and Vitória da Conquista. Photographic records from iNaturalist show the species further occurring in Condeúba and Ourolândia, also in Bahia.

Biological aspects

Specimens of Metallacantha aculeata gen. et sp. nov. were found resting atop or under bushes from 50– 210 cm above the ground, foraging and calling at night ( Fig. 17A View Fig ). In Santa Teresinha, specimens were found on or near Lantana L. ( Verbenaceae ) plants. Their green color matches with the color of the leaves, showing some camouflage despite their large body size. When handled, the individuals presented a warning display, raising their hind legs, ready to strike and push with the tibial spines if touched ( Figs 17B View Fig , 18E View Fig ). Both sexes of Metallacantha aculeata gen. et sp. nov. produced strong hissing sounds when disturbed, males by tegminal stridulation and females probably by also scraping their tegmina. Specimens from Santa Teresinha were reared briefly in captivity and ate leaves and flowers of different species of Lantana .

Bioacoustics

CALLING SONGS ( Fig. 20 View Fig ): Male calling songs were perfectly audible at distances of around 5 m in the field at night. Only calling songs at 23–24°C and 75% humidity were considered for analysis during nighttime. In the calling songs, males produce echemes of 4.2 ± 0.8 s (3.1– 6.18 s), with a regular intensity ( Fig. 20A–C View Fig ). The echemes are constituted by two single syllables, each one lasting 9.6 ±0.9 ms (7.5–12.5 ms) with a mute interval of 4± 0.8 s (2.9– 5.96 s) ( Fig. 20B–C View Fig ). Echemes are separated by a mute interval of 15.75± 5.9 s (36.5– 11.2 s) ( Fig. 20A View Fig ). Syllables are emitted with a dominant frequency of 10.5±1.8 kHz (7.7–13.3 kHz), the lowest frequencies were about 4.3±0.4 kHz (3.3–5.2 kHz) and the highest frequencies at 20.3±1.5 kHz (18.1–26.3 kHz), with a bandwidth of 90% of 5.7 ±0.2 kHz (5.4–6.2 kHz) ( Fig. 20D–E View Fig ).

AGGRESSIVE SONGS ( Fig. 21 View Fig ). The aggressive songs of males are sonorously similar to their calling songs but more vigorous, whereas females make a lower-pitched hissing sound, which is also made by scraping, probably with the wings. Males emit echeme sequences of about 0.6 ± 0.04 s (0.3– 0.8 s) of duration, composed by 16±2 echemes (5–22 echemes) ( Fig. 21A–B View Fig ). Each echeme is composed of two syllables, each one lasting 2.5±0.5 ms (3.9–1.5 ms), and echemes with a duration of 7.1 ±3.1 ms (10–4 ms), with a mute interval of 2±0.6 ms (1.2–3 ms) between syllables and 5.2±1.5 ms (3.4–6.3 ms) between echemes ( Fig. 21B–C View Fig ). Peak frequency was different between the first and second syllable, of about 12.3 ±1 kHz (10–13 kHz) in the first syllable and 8.9±0.7 kHz (7.4–9.9 kHz); the bandwidth of 90% was almost equal between the first and the second syllable, 4.4 ±0.7 kHz (2.7–6.1 kHz) in the first syllable and 4.5±0.4 kHz (3.4–5.4 kHz) in the second one ( Fig. 21C–D View Fig ). In the same behavior, females emit syllables that do not form echemes, and each syllable has a duration of 41±4 ms (33–44 ms); the peak frequency was 3.8±1.3 kHz (1.2–5.8 kHz), with a bandwidth of 5.4±0.5 kHz (4.1–5.8 kHz) ( Fig. 21G–H View Fig ).