Two new genera of Acanthopidae (Mantodea) from the Amazon region, with description of a new species

ABSTRACT Despite recent developments in the systematics of Acanthopinae Burmeister, 1838, the generic identity of two species, Acanthops parva Beier, 1942 and A. soukana Roy, 2002 remained ambiguous. The examination of the types and of previously unstudied specimens necessitated the creation of two new genera. Royacanthops n. gen. is introduced to accommodate Acanthops soukana Roy, 2002, and a new species from Brazil. Parvacanthops Schwarz & Moulin, n. gen. is proposed for Acanthops parva Beier, 1942. The resulting new combinations are Royacanthops soukana (Roy, 2002) n. comb. and Parvacanthops parva (Beier, 1942) n. comb. The male of R. soukana n. comb. is described for the first time. Three specimens from Brazil are described as Royacanthops confusa Schwarz & Moulin, n. gen., n. sp. The new genera are easily separated from other genera of Acanthopinae by morphological and genital characters. The geographic distribution of the two genera is briefly discussed. RÉSUMÉ Deux nouveaux genres d'Acanthopidae (Mantodea) d'Amazonie, avec la description d'une nouvelle espèce. Malgré des travaux récents sur la systématique des Acanthopinae Burmeister, 1838, la situation de deux espèces, Acanthops parva Beier, 1942 et A. soukana Roy, 2002 est restée ambiguë. L'examen des types et des spécimens jusque-là non étudiés justifie la création de deux nouveaux genres. Royacanthops n. gen. est introduit pour accueillir Acanthops soukana Roy, 2002 et une nouvelle espèce du Brésil, et Parvacanthops Schwarz & Moulin, n. gen. est proposé pour Acanthops parva Beier, 1942, avec les nouvelles combinaisons Royacanthops soukana (Roy, 2002) n. comb. et Parvacanthops parva (Beier, 1942) n. comb. Le mâle R. soukana n. comb. est décrit pour la première fois. Trois spécimens du Brésil sont décrits comme Royacanthops confusa Schwarz & Moulin, n. gen., n. sp. Les nouveaux genres se distinguent nettement des autres genres d'Acanthopinae par des caractères morphologiques et génitaux. La répartition géographique des deux genres est brièvement discutée.


INTRODUCTION
The praying mantises (Mantodea Latreille, 1802) present a striking morphological diversity. In South America, the family Acanthopidae Burmeister, 1838 contains some of the most cryptic and bizarre-looking mantodeans. According to our current knowledge, species from this family in their adult state look like dead or decomposing leaves, pieces of degraded plants, or are colorful "flower mantises", while the first instars frequently mimic ants (e.g. Grimaldi & Engel 2005;Agudelo et al. 2019;Rivera & Svenson 2020;Schwarz et al. 2020;Scherrer & Aguiar 2021). The ecological similarities to the Paleotropical family Hymenopodidae Giglio-Tos, 1915 are quite striking. Rivera & Svenson (2016) produced the first exhaustive molecular phylogeny of Neotropical earless artimantodeans. This phylogenetic scheme has been adopted in Rivera & Svenson (2020: 130), who added updates on taxonomy and identification keys. These authors treat Stenophyllidae Saussure, 1869 and Acontistidae Giglio-Tos, 1915 as separate families, while they were considered subfamilies before, and point out that half of the species of Acanthopidae Burmeister, 1838 are known by only one sex. The most recent integrative systematic arrangement of this family, based on morphological and genital synapomorphies, is given by Schwarz & Roy (2019: 111) (see also comments in Schwarz et al. 2020: 37). They propose to divide the family Acanthopidae into two subfamilies, Acanthopinae Burmeister, 1838 and Stenophyllinae Saussure, 1869, with the Acontistini Giglio-Tos, 1915 as a tribe of the latter.
In French Guiana, the diversity of Acanthopidae is high, with several genera and species known by only one specimen or one sex (Roy 2002a(Roy , 2004(Roy , 2015(Roy , 2019Moulin & Roy 2020). Acanthops soukana Roy, 2002 was described after a single female. Roy (2002a: 300) classified this 'remarkable' species in the genus Acanthops while indicating that it is distinguished from other species by the shape of its forewings and its coloration. Later, Schwarz & Roy (2018: 453) and Rivera & Svenson (2020: 133) indicated that the female holotype of A. soukana as well as the male of the Amazonian Acanthops parva Beier, 1942 are aberrant members of Acanthops and that the discovery of their opposite sex would confirm the generic identity of these species. Moulin & Roy (2020: 37) mentioned two individuals of A. soukana on the CardObs platform (https://inpn.mnhn. fr/espece/cd_nom/760691) of the "Inventaire national du Patrimoine naturel" (INPN, French natural heritage inventory), i.e., the female holotype and another specimen which sex was not specified. That individual is actually a male from the North-East of French Guiana, near Roura.
While working on the Acanthops preserved in the SMNK, the second author noticed two males from Brazil which fit the diagnosis of A. parva Beier, 1942sensu Lombardo & Ippolito (2004. One of them had a corresponding female, while the other, smaller one, bore an identification label "Acanthops erosula Stål, 1877; det. R. Ehrmann". The two males and the female were later (2020) assigned to A. parva and A. soukana, respectively, by the second author, but uncertainties about a putative synonymy of the two species remained. Examination of the male holotype of Acanthops parva Beier, 1942 showed that this taxon is not identical with the SMNK specimens nor with the specimen identified as A. parva by Lombardo & Ippolito (2004). The finding of the Guianese male finally confirmed that the Brazilian specimens represent an undescribed taxon.
In this study, we describe two new genera of Acanthopinae related to Plesiacanthops and Miracanthops to accommodate A. soukana from French Guiana and a new species from Brazil described below on one hand, and A. parva on the other hand. Royacanthops n. gen. is characterized by a prominent vertex with very large juxtaocular tubercles, a long and relatively slender pronotum, forewings with a strongly sinuate costal margin, abdominal tergites with remarkably large foliaceous lobes particularly in females, and the conformation of the male genitalia.
Parvacanthops Schwarz & Moulin, n. gen. is characterized by a small body size, a very convex and strongly tuberculate vertex, a pronotum with weakly expressed lateral expansions, forewings with a wide, gradually tapering costal margin without subapical and apical lobes, and the conformation of male genitalia. Morphological nomenclature and specimen preparation followed Brannoch et al. (2017), except for the following: head length includes the labrum, foretibia length includes the apical claw, and total length was measured from the vertex of the head to the tip of the abdomen. Genital dissection procedures and terminology follow Klass (1997) and Schwarz & Roy (2019). Specimens were studied using a Leica S8APO stereomicroscope connected to a Leica MC120 HD camera, or a Müller stereomicroscope.

MATERIAL AND METHODS
All measurements were taken with a caliper and are expressed in millimetres. The measurement of the total body length produces a general assessment of body size rather than an exact species-specific character, since head position, abdominal expansion, and wing position are all variable. The total body length should then only be used as a rough measurement to initially discriminate between the small and large Mantodea species when performing identifications.
Habitus images were taken with a Konica-Minolta Dynax 5D or with a Canon EOS60. Images of R. soukana (Roy, 2002) n. comb. were taken over an 18% grey card background for white balance standards. Photographs of R. confusa Schwarz & Moulin, n. gen., n. sp. and P. parva (Beier, 1942) n. comb. were taken against a white background 20 cm away using a Nissin MF18 macro ring flash. Images were processed in GIMP 2 and Adobe Photoshop CS5, respectively, to adjust levels, contrast, exposure, sharpness, and to add scale bars. Minor adjustments were made using the stamp tool to correct background aberrations and to remove distracting debris. Plates were constructing using Publisher 2016 and Adobe Photoshop CS5.

Distributions
The distribution map was created in QGIS software 3.8 Zanzibar, with administrative areas from GDAM, the database of Global Administrative Areas website (https://gadm. org/) (ig. 21).

MeasureMents
Antenna length. Anteroventral femoral spine count. All inner marginal ridge spines, except the distal genicular spur. Anteroventral tibial spine count. All inner marginal ridge spines, except the distal terminal spur. Body length. Length of body from vertex to posterior tip of abdomen (intraspecifically variable measurement, primarily for general size estimation). Comparative wing length. Ratio tegmen to pronotum length. Costal field width. Width at the widest point. Forewing length. From proximal margin of axillary sclerites to distal tip of the discoidal region. Forewing width. Width at the widest point. Head length. Length of head from vertex to bottom margin of labrum. Head width. From lateral margins of the eyes at the widest point. Hindwing length. From proximal margin of axillary sclerites to distal tip of the discoidal region.
Mesothoracic femur length. From most proximal margin abutting the trochanter to the distal side of the terminal spine insertion site. Mesothoracic tibia length. From most proximal groove near joint with the femur to the distal side of the terminal spine insertion site. Metathoracic femur length. From most proximal margin abutting the trochanter to the distal side of the terminal spine insertion side. Metathoracic tibia length. From most proximal groove near femoral joint to the distal side of the terminal spine insertion site. Metazona length. Center of supra-coxal sulcus to posterior margin. Pronotum length. From anterior margin to posterior margin. Pronotum shape. Ratio metazona to prozona. Pronotum width. From the lateral margins at the widest point, the supra-coxal bulge. Posteroventral femoral spine count. All outer marginal ridge spines, except the distal genicular spur. Posteroventral tibial spine count. All outer marginal ridge spines but except the distal terminal spur. Prothoracic coxa length. From pronotal insertion to trochanter. Prothoracic femur length. From proximal margin abutting trochanter to distal margin of genicular lobe. Prothoracic femur width. From dorsal to ventral margin, at the widest point. Prothoracic tibia length. From joint with femur to apex of apical claw. Prozona length. Anterior margin of pronotum to center of supra-coxal sulcus. Ratio forewings. Ratio between forewings length to width. Ratio pronotum. Ratio between pronotum width and length. Diagnosis. -Habitus typical for the subfamily, brown, resembling a dry leaf, with a slender pronotum as in Plesiacanthops and Miracanthops. Both sexes with convex vertex and prominent, tuberculate juxtaocular bulges; frontal shield with two projections on dorsal margin; pronotum long and relatively slender, with tuberculate prozona and two pairs of stronger tubercles anterior and posterior to supracoxal sulcus, respectively; dorsal margin of forefemora with a small but distinct basal lobe; spination formula of the foreleg F = 4DS/15-19AvS/6PvS; T = 17-22AvS/20-23PvS; forewings with costal margin strongly sinuate; alae shorter than tegmina; abdominal tergites with remarkably large foliaceous lobes; abdominal sternites with three posterior lobes; cerci short, the last segment flattened and indented, with the outer lobe just slightly larger than the inner lobe. Male. Pronotum with lateral margins of the metazona slightly produced, forming a distinct expansion along its length; walking-leg femora with rounded genicular lobes; subapical margin of forewings with a small but distinct lobe; alae with a triangular apex; genitalia with acute bl, a sinistrally re-curved sdp, a simple, serrated afa, and a large loa consisting of two lobes. Female. Pronotum with teeth along margin of the metazona; walkingleg femora with acute genicular lobes.  (Roy, 2002)  Coloration and habitus. Body and wings brown, resembling a dry leaf.

Royacanthops soukana
Head ( Fig. 2A). Triangular in frontal view, spotted with dark, without projections. Antennae moniliform, shorter than body, bearing black setae; scape and pedicel ochraceous; flagellum black. Vertex convex, higher than compound eyes, with small tubercles. Juxtaocular bulges protruding, with several small tubercles. Eyes rounded, with a small dorsolateral process. Lower frons wider than high, with two small projections on upper margin. Pronotum (Fig. 2C). Elongate, light brown with brown spots and a pair of darker spots at around two-thirds of the metazona. Prozona with smooth margins, and armed with four pairs of pointed tubercles, growing larger from front to back. Metazona with a fine and sparse denticulation along its lateral margins; armed at the posterior end of supracoxal dilatation with two paramedian conical tubercles with a blunt point.
Meso-and metathoracic legs. All segments setose. Coxae robust, relatively long. Femora slightly widened, with a deeply concave ventral margin, accommodating tibia when at rest; genicular lobes short and rounded. Tibiae darker, slightly arched, mesothoracic tibiae distinctly swollen in the basal half, metathoracic tibiae for almost two thirds of their length, with a very short apical lobe and two black terminal spines; tarsi with first tarsomere shorter than next four together.

Wings (Figs 1; 2B).
Forewings subopaque, brown, resembling dry leaves, with the postero-apical region more hyaline; costal area brown, slightly darker, opaque; costal area strongly sinuated, widest at about first quarter of wing, then convexly tapering towards Subcostal posterior at apical third of wing; subapical lobe weakly developed; stigma pale, almost hyaline. Hindwings with an ochraceous, spotted costal area; proximal part of discoidal and anal areas smoky; discoidal area with a well-developed apical lobe and two smaller lobes posteriad.
Abdomen (Fig. 3). Light brown, fusiform, shorter than wings; tergites 3 and 4 with thin lateral extensions; tergites 5 and 6 with large lateral, irregularly toothed lobes, more devel- oped on tergite 5; tergites 7 and 8 with small lateral lobes. Supraanal plate deeply indented, bearing short cerci, the last segment flattened and indented, with the outer lobe larger than the inner lobe. Sternites each with a median and two paramedian lobes at posterior margin. Subgenital plate with two small styli.
Genitalia (Fig. 4). L4A longer than wide; sdp very elongate and re-curved, with acute apex and with several small denticles at the base; bl on right site of ventral phallomere well developed, elongate, thin, with truncate apex and a sclerotized acute process pointing to the left. L4B with afa sclerotized, distally more so, short, with several sclerotized spines; loa setose, anterior lobe with elongate setae, posterior lobe with roughly triangular apex, indented on the left side; paa curved at the end, with a subapical digitiform process rendering the apex hammerhead-shaped. Ventral lamina longer than wide, with a wide sclerotized area; R3 with digitiform pia bearing several sclerotized teeth, and a well sclerotized pva.     (Figs 6; 7). Body and wings brown, resembling a dry leaf.

Coloration and habitus
Head (Fig. 9A, B). Triangular in frontal view, tuberculate, spotted with dark, without projections. Antennae moniliform, shorter than body, of general body color, segments darkened apically, flagellum bearing darkened setae. Vertex convex, higher than compound eyes, with small tubercles. Juxtaocular bulges protruding, with several small tubercles. Eyes ovoid, rounded anteriorly, with a small, conical, dorsolateral process. Lower frons wider than high, with two small projections on upper margin. Pronotum (Fig. 10A, B). Elongate, light brown with brown spots and a pair of darker spots at around two-thirds of the metazona. Prozona with smooth margins, and armed with three pairs of pointed tubercles, growing larger from front to back, and 1-2 additional single tubercles. Metazona as in R. soukana (Roy, 2002) n. comb., with an indistinct, sparse denticulation on the lateral margins.

Meso-and metathoracic legs
Wings (Figs 6; 7). Forewings subopaque, brown, resembling dry leaves, with the postero-apical region more hyaline; costal area brown, slightly darker, opaque; costal area strongly sinuated, widest at about first quarter of wing, then convexly tapering towards Subcosta posterior at apical third of wing; subapical lobe weakly developed; stigma irregularly shaped, opaque, shiny. Hindwings with an ochraceous, spotted costal area; proximal part of discoidal and anal areas smoky; discoidal area with a well-developed apical lobe and two smaller lobes posteriad.
Abdomen. Dark brown, fusiform, shorter than wings; tergites 3 and 4 with acute, triangular extensions; tergites 5 and 6 with large lateral, irregularly toothed lobes, more developed on tergite 5; tergites 7 to 9 with small subacute lobes. Supraanal plate deeply indented, bearing short 11-segmented cerci, first and last segment consisting of 3 and 2 fused segments, respectively. Apex of last segment flattened and indented (Fig. 13A, B), with the outer lobe larger than the inner lobe. Sternites each with a median and two paramedian lobes at posterior margin. Subgenital plate with two small, conical styli. Genitalia (Fig. 13C, D). Ventral phallomere (L4A) longer than wide; sdp very elongate and re-curved, with acute apex and with several small denticles at the base; bl on right site of ventral phallomere well developed, digitiform, with a very short spine accompanied by a yet shorter spine on the right apical margin. L4B with afa sclerotized, distally more so, short, with several sclerotized spines. Membranous lobe setose, anterior lobe with elongate setae, posterior lobe with roughly triangular apex, indented on the left side. Apical process digitiform, curved at the end. Right phallomere with pia bearing several sclerotized ridges, and a well sclerotized, L-shaped pva.

reMarks
The two males from the SMNK correspond very well to the specimen from the ANSP investigated by Lombardo & Ippolito (2004). The holotype from Roraima is distinctly larger than the two other known males, but agrees well in all other characters with the specimens from the lower Amazon. The paratype from Manaus has an aberrant configuration of posteroventral spines on the left femur (Fig. 11C). While the total spine number is six, the fifth spine is distinctly smaller than the others, and there is a callus between this spine and the sixth, where an additional spine was supposed to be. This spine seems to have been lost during postembryonic development. This specimen also has the right stylus shorter than the left one, a feature that is not apparent in the holotype (Fig. 13A, B). An interesting feature in most Acanthopoidea is the irregular size of bendable anteroventral spines. In most artimantodeans, the anteroventral row consists of short, rigid spines alternating with long, bendable spines (except the apical ones) (pers. obs.). In Acanthopoidea (except Angelidae Beier, 1935) the proximal 4-6 spines are arranged in two rows, with the medial (= inner) row consisting of bendable spines. As seen in the configurations here, the bendable spines in this group may be shorter than neighboring rigid spines. Coloration and habitus (Fig. 8). Body and wings light brown, resembling a dry, shriveled leaf. Head (Fig. 9C). Triangular in frontal view, without projections but tuberculate. Antennae moniliform, slightly longer than head, ochraceous, along first half of flagellum darkened at every second segment apex, in the second half at each segment. Vertex convex, slightly arched, higher than compound eyes, with four tubercles in a trapezoid arrangement. Juxtaocular bulges very large, protruding, with several distinct tubercles. Ocelli small. Eyes ovoid, with a blunt, triangular, dorsolateral process. Lower frons distinctly wider than high, with two small projections on upper margin. Pronotum (Fig. 10C). Elongate, tuberculate along its entire length, light brown with a pair of darker patches at around two-thirds of the metazona. Prozona with almost smooth margin, tuberculate, and with two pairs of robust paramedian projections, the posterior ones being larger. Supracoxal dilatation distinct, with subcircular margins. Metazona with parallel margins, 2.4 times as long as prozona, tuberculate, with a pair of robust paramedian projections at the posterior end of supracoxal dilatation and a pair of triangular projections at base; margins of metazona with thick, rounded teeth along their length.
Prothoracic legs (Fig. 11E, F). Same coloration as head and pronotum. Coxae trapezoid in cross-section; anterior sides tuberculate, with numerous whitish spots; posteroventral side with a few robust tubercles, some of them darkened; ventral margin with an irregular row of inclined small teeth; dorsal margin with 6 stronger, pale teeth interspersed with smaller teeth; apical lobes contiguous. Trochanter tuberculate. Femora triangular in cross-section; posterior side with several tubercles, some of them darkened, with 6 posteroventral spines; margin between spines heavily crenelated. Dorsal margin crenelated, with a small but distinct, darkened, triangular lobe at base; anterior side densely covered with light ochraceous spots, with two interrupted darker bands at middle and across femoral brush, respectively, and with dark spots at bases of the larger antero-ventral spines; clawgroove at basal fourth of femur; 18-19 anteroventral spines and 4 discoidal spines with brown tips; AvS configuration IiIIiIiIiIiIiIiiiI (right) and IiIIiIiIiIiIiiIiiiI (left). Tibiae with convex dorsal margin, spotted with dark and with somewhat darker apex; 23 posteroventral, decumbent spines, plus an additional, vestigial, thin spine on left tibia located before the antepenultimate spine (Fig. 11E); all spines with dark tips; 20-22 anteroventral spines with dark tips, spines on right tibia showing some size anomalies towards apex. Tarsi broken off near base, remaining parts dark. (Fig. 8B). With slight pubescence. Coxae relatively long, heavily keeled, dorsal side concave, accommodating femur when at rest. Femora rectangular in cross section, slightly widened, with a deeply concave ventral margin, accommodating tibia when at rest; genicular lobes acute. Tibiae keeled, somewhat darker dorsally, slightly arched, mesothoracic pair distinctly swollen in the basal half, metathoracic pair for almost two thirds of their length, with a triangular apical lobe and two terminal spines. Tarsi darkened, with first tarsomere much shorter than the remaining tarsomeres taken together. (Figs 8; 12). Forewings opaque, vein configuration resembling a dry leaf, spotted with brown, apical margin darkened; costal area strongly sinuated, widest near base, then convexly tapering towards Subcosta posterior at apical third of wing, then widening again into a triangular subapical lobe; Apex of forewing elongated into a digitiform lobe slightly widened at its end (apical half broken off on right tegmen); posterior margin of forewing subapically with three small lobes surrounding vein apices. Stigma triangular, shiny, light chestnut in color. Hindwings yellowish with dark apex; cells irregularly darkened in their middle, except those at base and along anterior margin of discoidal field; anal area relatively small; apex subtruncate, with slightly undulated margin. Abdomen (Fig. 8B). Brown, ovoid but appearing roughly circular due to lateral tergal lobes, shorter than wings. Tergites shiny, tergites 3-8 with a black band at posterior end, widest on tergite 4; tergites 3 and 4 with slender, triangular lateral lobes; tergites 5 and 6 each with a large, irregularly toothed, lateral lobe, more developed on tergite 5; tergites 7, 8 and 9 with small lateral lobes. Supraanal plate wider than long, deeply indented at apex. Cerci short, 11-segmented, the last segment flattened and indented, with the outer lobe only slightly larger than the inner lobe. Sternites each with a wide median and two acute paramedian lobes at posterior margin. Subgenital plate without peculiarities.

Differential Diagnosis
Males of R. confusa Schwarz & Moulin, n. gen., n. sp. can be distinguished from those of R. soukana (Roy, 2002) n. comb. by their comparatively shorter alae, a much weaker apical spine on bl pointing distad instead of sinistrad, and paa lacking a subapical lobe. Females of R. confusa Schwarz & Moulin, n. gen., n. sp. can be distinguished from those of R. soukana (Roy, 2002) n. comb. by their more distinct and rounder supracoxal dilatation, the thick and rounded vs smaller triangular teeth on the metazonal margin, the flatter subapical lobe on the tegmen, and the long, digitiform (vs short triangular) apical lobe.  and without subapical lobes on tegmina. Male with convex vertex armed by a paramedian pair of strong double tubercles; juxtaocular bulges moderately developed, tuberculate; frontal shield with two projections on dorsal margin; pronotum long and relatively slender, prozona with three pairs of tubercles, metazona without strong tubercles posterior of supracoxal sulcus; metazona of males with parallel margins, expansion along its length very indistinct in the anterior half, more developed in the posterior half; dorsal margin of forefemora with a very indistinct basal lobe; walking leg femora with subtriangular genicular lobes in males; forewings with very wide costal field gradually tapering towards apex; alae longer than tegmina in males, with a triangular apex; abdominal tergites with small triangular lobes; abdominal sternites with three posterior lobes; cerci short, the last segment flattened and indented, with the outer lobe just slightly larger than the inner lobe; genitalia with long bl curved to the left and with subacute apex, a long, dorso-dextrally curved sdp, a simple afa, and loa consisting of two rather small, setose lobes. Spination formula F=4DS/16AvS/6PvS; T=18AvS/24-25PvS.
etyMology. -Name consisting of the Latin prefix "parv-" (small) and "-acanthops", alluding to the small body size when compared to other members of the group.

Coloration and habitus.
Body and wings dark brown, resembling a dry leaf (Fig. 14A).
Head (Fig. 15). Triangular in frontal view, with pale spots. Antennae missing. Vertex very convex, with two paramedian bicuspidate tubercles. Juxtaocular bulges moderately protruding, with several small tubercles. Eyes rounded, with a small dorsolateral tubercle located slightly mediad from lateral margin of eye. Lower frons wider than high, with two rather long conical projections on upper margin. Pronotum (Fig. 14A). Elongate, brown, mottled with dark brown and pale, pair of darker spots at two-thirds of the metazona indistinct in the type. Prozona with smooth margins, and armed with six pairs of pointed tubercles, growing larger from front to back. Metazona indistinctly tuberculate, with almost smooth lateral margins; lateral expansion very indistinct in anterior half, becoming slightly wider in posterior half.
Prothoracic legs (Fig. 16). Same coloration as head and pronotum. Coxae rectangular, trapezoid in cross-section, with one or two stronger tubercles among scattered smaller tubercles on posteroventral side, and 15-18 very small dorsal spines of inequal size; anterior side with numerous pale spots. Trochanter slightly granular. Femora triangular in cross-section, spotted, with 6 posteroventral spines; margin between spines crenelated; dorsal margin almost smooth, with an indistinct lobe at base; 16 anteroventral spines, and 4 discoidal spines, large anteroventral spines with a dark spot around base. AvS configuration IiiIiIiIiIiIiIiI. Claw-groove at basal fourth of femur. Tibiae dark brown, spotted with pale; 24-25 decumbent, rather small posteroventral spines; 18 anteroventral spines; first tarsomere longer than remaining tarsomeres together.
Meso-and metathoracic legs. Typical for the group. All segments setose. Coxae robust, relatively long. Femora slightly widened, with a deeply concave ventral margin, accommodating tibia when at rest; genicular lobes triangular. Tibiae slightly arched, mesothoracic tibiae indistinctly swollen in the basal half, metathoracic tibiae for almost two thirds of their length, with a very short apical lobe and two proximally black terminal spines; tarsi with first tarsomere shorter than next four taken together.
Wings (Fig. 17). Forewings opaque, brown, resembling dry leaves, with the postero-apical region subopaque; costal field widest at about first quarter of wing, then tapering towards apex; forewing without subapical and apical lobes; stigma irregularly shaped, opaque, shiny. Hindwings with an ochraceous, spotted costal area; proximal two-thirds of discoidal and anal areas smoky; subapical part of hindwing subhyaline, apex subopaque; discoidal area with a distinct apical lobe. Abdomen. Dark brown, fusiform, shorter than wings; tergites with small triangular extensions. Supraanal plate deeply indented, bearing short 9-segmented cerci, first and last segment consisting of 3 and 2 fused segments, respectively. Apex of last segment flattened and indented (Fig. 18A), with the two lobes of roughly the same size. Sternites each with a median and two paramedian lobes at posterior margin. Subgenital plate with two small, conical styli. Genitalia (Fig. 18B). Ventral phallomere longer than wide; sdp very elongate, curved dorso-dextrad, with acute apex point-ing antero-sinistrad; bl on right side of ventral phallomere well developed, digitiform, apical part curved sinistrad, with subacute apex. Left phallomere with a simple, sclerotized afa. Membranous lobe indistinctly setose, not well developed. Apical process digitiform, curved at the end. Right phallomere as in related species.

reMarks
The holotype male is in relatively good condition, given its age and history. Pronotum, right femur, right hind leg, and abdomen are glued to the specimen, the latter with the ventral side up. The right forewing is also slightly damaged, and the antennae are missing. However, most taxonomically significant parts are still present.

Female
Unknown.  (Fig. 19) and the male by light trapping in a tree (Fig. 20). Interestingly, none of our R. confusa Schwarz & Moulin, n. gen., n. sp. specimens was obtained by light trapping. The male from Manaus was found in a fogging sample. The pair from Roraima has the same collection dates. Given the lack of flight ability in females and the notorious rarity of acanthopines in the wild, the respective pair had likely been found by manual searching while engaging in copulatory behavior. For the reasons given above, it is often difficult to draw conclusions on the microhabitat of a given species. While their preference for forests seems to be well supported, whether they inhabit mainly the canopy or are spread out across vegetation layers remains a matter of debate. At least some species of Acanthopinae are considered canopy dwellers (Rivera & Svenson 2016). The rarity of females might better be related to a lack of sampling effort. It is worth noting that no females of these two genera have been observed in more than twenty years.
According to our current, admittedly incomplete, knowledge, the genus Royacanthops n. gen. seems to be restricted to the northern part of the lower Amazon east of the Rio Negro, including the Guyanas (Fig. 21). It does not seem to overlap with the distributional area of the more westerly Miracanthops. Parvacanthops Schwarz & Moulin, n. gen. is only known from the male holotype collected south of the Amazon along the Rio Tapajos in the Brazilian state of Pará. These three genera have distinctly allopatric ranges according to current data. In contrast, Plesiacanthops, initially only known from the Guyanas, has a representative in the Western Amazon (Schwarz unpubl.).
There are still some difficulties in species identification in Acanthopinae, mainly due to marked sexual dimorphism. Females of some taxa remain elusive to this day, the most notorious example being the genera Lagrecacanthops and Parvacanthops Schwarz & Moulin, n. gen. The use of DNA barcodes can be of great use in associating sexes or taxa with each other (Scherrer 2014; Moulin in press), or to high-   light a cryptic species (Moulin 2020;Decaëns et al. 2021) when other criteria of integrative taxonomy have remained ineffective. More extensive molecular sampling within the well-diversified Acanthopinae is needed to test phylogenetic hypotheses (Rivera & Svenson 2016). As described in other groups of organisms (Guarnizo et al. 2015), we can also expect that the use of DNA barcoding, given exhaustive taxonomic and geographic coverage, will continue to modify our current perception of diversity distributed among biogeographical areas.