Arumatia Ghirotto & Crispino & Engelking & Neves & Góis & Chiquetto-Machado 2022, gen. nov.
Creators: name: Ghirotto, Victor Morais
name: Crispino, Edgar Blois
name: Engelking, Phillip Watzke
name: Neves, Pedro Alvaro Barbosa Aguiar
name: Góis, Júlia de
name: Chiquetto-Machado, Pedro Ivo
Publisher: name: Zenodo
Year: 2022
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Orthoptera
Diapheromeridae
Arumatia

description: Genus Arumatia Ghirotto gen. nov.
urn:lsid:zoobank.org:act: AF3FA2A0-9EBC-421C-A8CE-0244D8EB10A1
Figs 1–52
Type species
Arumatia aramatia Ghirotto gen. et sp. nov. by present designation.
Species included
Arumatia dubia (Caudell, 1904) gen. et comb. nov.
Arumatia fulgens (Zompro, 2004) gen. et comb. nov.
Arumatia anyami Ghirotto, Crispino & Neves gen. et sp. nov.
Arumatia crassicercata Ghirotto, Crispino & Engelking gen. et sp. nov.
Arumatia aramatia Ghirotto gen. et sp. nov.
Arumatia motenata Ghirotto gen. et sp. nov.
Arumatia diamante Ghirotto gen. et sp. nov.
Diagnosis
Elongate, small- to medium-sized, apterous stick insects. General features that allow the distinction of Arumatia Ghirotto gen. nov. from almost all other Diapheromerinae genera are the elongate head and body, thin legs with carinae bearing spiniform setae and very long basitarsi. Females can be further distinguished by the very long cerci and a shortened and acute subgenital plate covering the gonapophyses and gonoplac. Males are further distinguishable by the shortened sternum IX (lacking a portion anterior to the poculum) with asymmetric anterior margin delimiting an asymmetric poculum that is also partly fused to the sternum VIII. In most phasmids the male sternum IX is divided into an anterior portion that is similar in aspect to other sterna and a posterior specialised symmetric poculum that holds the male genitalia. In Arumatia gen. nov. the sternum IX is entirely specialised as an asymmetric poculum.
Arumatia Ghirotto gen. nov. has remarkable similarities with representatives of Phantasca Redtenbacher, 1906 (Diapheromerinae: Diapheromerini), including the general aspect of the subgenital plate, gonapophyses and gonoplac in females, the shortened, asymmetric and partly fused sternum IX and the tergum IX with lateral margins approaching each other ventrally in males, as well as general egg morphology.
Arumatia Ghirotto gen. nov. can be distinguished from Phantasca by the following set of characters. In both sexes: smaller and less protruding eyes and more elongate head and basitarsi. In females: narrower and longer legs, tergum VIII not significantly shorter than tergum X, very long and large cerci (always longer than tergum X), shortened and thicker gonapophyses, straight gonapophysis VIII (long and upcurving in Phantasca) and longer gonoplac. In males: absence of wings, longer metanotum and much shorter median segment, large and elongate vomer and sternum VIII and tergum VIII not fused but clearly separated (fused in Phantasca). Although males of Arumatia gen. nov. are readily distinguishable even by the naked eye from males of Phantasca by the significantly more elongate head, smaller eyes and absence of wings, females of Arumatia gen. nov. can be somewhat difficult to distinguish at first sight from females of some slender species of Phantasca with relatively long cerci.
Etymology
Taken in reference to the word Arumatiá, an indigenous name for stick insects in Brazil first recorded by Marcgravi (1648) and still used as a popular name for stick insects in some regions of the country. The gender is feminine.
Description
LENGTH. 66–113 mm for females; 56–70 mm for males.
HEAD. Elongate and smooth with sparse setae, vertex flat. Eyes small and slightly oval in outline. Galea elongate to broad, elliptical and bearing long setae, apically with dense tuft of hairy and large microtrichia forming round patch or band along apical edge. Galealobulus present, small, widely round and basally fused to galea. Labrum strongly notched anteromedially, round and asymmetric with right lobe significantly larger than left one. Antennae long, scapus longer than wide, basally constricted in dorsal view and slightly compressed dorsoventrally. Pedicellus subglobose.
THORAX. Smooth. Pronotum slightly longer than wide, transverse sulcus conspicuous and straight to gently curved. Profurcasternum round in females and oval in males. Mesothorax 4.8–7 × as long as prothorax. Mesonotum with a pair of lateral carinae continuing through metanotum and median
segment, mesepisternum lanceolate and regularly widening posteriorly, mesepimeron moderately elongate and slightly exceeding end of mesothorax. Metepimeron extremely elongate extending across entire length of median segment, posteriorly pointing and slightly exceeding posterior margin of median segment. Posterior margin of metanotum and anterior margin of median segment slightly widened, more conspicuously in females.
LEGS. Slender, and unarmed. Anterior legs ca as long as or slightly longer than hindlegs, midlegs distinctly shorter. Profemur with distinct basal curvature. Femora and tibiae with five carinae with or without few sparse setae among them. Carinae of profemora and protibiae distinctly keeled, mid and hind femora and tibiae weakly to distinctly keeled. Carinae of all femora, tibiae and tarsi bear one or two rows of short setae. On antero-, posteroventral and ventral carinae, last 1–3 setae stouter and spiniform in most species, and in some species on anterodorsal and posterodorsal as well. In two species, these three ventral carinae ending in apical spiniform projection. Ventral, antero- and posteroventral carinae of basitarsi frequently with longer or stouter (spiniform) setae mainly present on mid and hindlegs. All basitarsi very elongate, of about same length to significantly longer than respective following tarsomeres combined. Euplantulae well developed in all tarsomeres; composed of two symmetrical pads separated by a median groove in tarsomeres I–III, of two symmetrical pads to single domed pad in tarsomere IV, and of single flattened lobed pad in tarsomere V (which can be less developed in some species).
ABDOMEN. Smooth and bearing few setae across entire length. Median segment ranging from slightly more than half the length to same length as metanotum. Median segment anteriorly marked by two parasagittal ovoid stains. Combined length of segments II–X slightly longer than combined length of head, thorax and median segment. Terga II–VII and sterna II–VIII bear discrete lateral carinae near lateral margins. All segments longer than wide. Segments III–VII longest. In females: tergum X conical in lateral view, in dorsal view just slightly narrower towards apex, posterior margin round to strongly emarginate. Epiproct domed in dorsal view, short to very elongate. Paraprocts elongate and posteriorly acute, straight, setose on posterior margin, laterally bearing the cerci and not concealing them from ventral and lateral views. Cerci extremely elongate, straight, pointing to posterior, gradually tapering and ranging from slightly longer than terga IX to longer than IX, X and epiproct combined. Praeopercular organ absent, small and verruciform or conspicuously lobed and pointing towards posterior region. Subgenital plate roundly lanceolate to slightly more acute, reaching from ¼ of length of tergum X to slightly exceeding posterior margin of tergum X, bearing two parasagittal carinae beginning on anterior margin and running half the length of segment before becoming flatter and more setose, gradually tapering towards posterior. Subgenital plate totally covering gonapophyses and gonoplacs. Gonapophyses and gonoplacs flattened, dorsoventrally for gonapophyses VIII, lateroventrally for IX and laterally for gonoplacs. Gonapophyses VIII shorter in some species or longer than IX and gonoplacs in others, IX shorter than VIII and gonoplacs or slightly longer than VIII, gonapophyses VIII linear to lorate (having form of strap) and blunt to tapering towards the posterior, IX lorate to conical and tapering towards posterior. Gonapophyses IX ventrally folded to fit within gonapophyses VIII. Gonangulum distinctly reduced, flat and not lobed. Gonoplacs significantly elongate, basally widened, subsequently linear to lorate, setose, slightly shorter than both gonapophyses or exceeding both gonapophyses. In males: tergum X longer than wide, slightly widening towards posterior and roundly or v-shaped emarginate on posterior end. Thorn pads composed of ca 25 to 35 strong curved teeth, restricted to ventral area of posterior margin or extending ventrally and laterally on ventral area of posterior margin of latero-ventral flat flexing expansions. Cerci slightly shorter than tergum X, inwardly curved and with round apex. Epiproct discrete and hidden from dorsal view. Vomer elongate, dorsoventrally flattened (similar to most stick insects) or convex, terminal hook elongate and strongly sclerotized, either acute, single pointed or symmetrically bifid near posterior margin, presenting round apices. Tergum VIII very slightly longer than IX, curving towards ventral region near posterior margin and tapering towards anterior in lateral view. Sternum VIII completely separated from tergum VIII and partly fused with sternum IX. Delimitation between terga VIII and IX
as asymmetric sulcus extending towards anterior on left side. Sternum IX reduced, presenting only as poculum without evident anterior region. Due to asymmetry, poculum shorter on right side than left side. Poculum conical to round in lateral view, slightly wider than long, or longer than wide when viewed ventrally, posterior margin with wide emarginate curvature medially. Phallic organ bearing very elongate dorsal sclerite penetrating inside body cavity, wide longitudinal lobe with fine granulation and smaller basal lobe ventrally on right side.
Egg
Relatively small. Capsule subrectangular to ovoid and may or may not be constricted at opercular collar, laterally compressed. Capsule surface smooth, slightly roughly textured with lumpy or net appearance or roughly textured with small irregular reticulate ridges. Colour varying in shades of orangish or reddish brown, rarely greyish, with lighter band on dorsal surface extending towards anterior and posterior. Micropylar plate elongate, elliptical, with lighter elevated outer circle delimiting darker inner flat region connected to micropylar cup. Micropylar cup small and rounded, only slightly elevated. Median line short. Opercular collar narrower (constricted) than rest of capsule or of same width, not constricted. Opercular collar with minute and delicate bristles along edge. Operculum oval and with non-stalked capitular structure formed by irregularly reticulated or radially directed ridges and elevations of amberlike colour and texture.
Distribution (Fig. 52)
Arumatia gen. nov. is restricted to South America and so far only recorded from Brazil and Paraguay. While Arumatia anyami gen. et sp. nov. possibly occurs in the Amazon Forest along the border with Bolivia, all other species occur in the Cerrado (Fig. 53). Arumatia dubia gen. et comb. nov. is widely distributed in the Cerrado but is also recorded from the Chaco. The Cerrado, Chaco and other biomes such as the Caatinga are part of the South American Dry Diagonal, presenting environmental and faunal similarities (Vanzolini 1963; Prado & Gibbs 1993; Collevatti et al. 2020). Records from iNaturalist (Fig. 52: grey dotted shields) and the occurrence of species in close contact with the Caatinga (Fig. 52: x mark) suggest that the genus is also present in the xeric Caatinga biome. The Cerrado domain is a complex of biomes (see Fig. 53), and representatives of the genus are recorded for seasonal forests and savannah formations (Fig. 53). It is worth noting that A. anyami, the only Amazonian species of the genus, occurs in a region in close contact with the Beni savannahs of Bolivia (Fig. 52) and there is a possibility that it inhabits savannah formations present in small patches around the type locality. In Fig. 52, the shield symbol represents unidentified and potentially new species: one unidentified nymph in the MZUSP collection, in the Cerrado in the south of Mato Grosso State (Fig. 52: dark grey shield) and two records from iNaturalist of a potentially new species from Olho d’Água das Flores, Alagoas State and Campo Formoso, Bahia State, both in the xeric Caatinga biome (Fig. 52: grey dotted shields). We further plotted five points in Fig. 52 representing photographic records from iNaturalist of A. dubia from several localities, in Paraguay as well as Southeast and Central-West Brazil (Fig. 52: grey dotted circles).
Remarks
As mentioned in the diagnosis of Arumatia gen. nov., this genus shares a number of features with representatives of Phantasca, including the male sternum IX entirely specialised as an asymmetric poculum. Phantasca was revised by Hennemann et al. (2018) and is restricted to the Amazon region in South America, with most species inhabiting French Guiana.Although these authors discussed the absent or reduced anterior portion of the sternum IX which occurs in Phantasca and other Diapheromerinae genera (as well as in Arumatia gen. nov.), they did not mention the asymmetry of the poculum, a feature
present in several species of Phantasca as seen from pictures provided by them (Hennemann et al. 2018: figs 13, 24, 32, 62, 70, 77, 97, 116). However, to the best of our knowledge, no other Diapheromerinae is known to have an asymmetric poculum, which also includes representatives of genera with an absent or reduced anterior portion of sternum IX (that however have a symmetric poculum), which according to Hennemann et al. (2018) are closely related to Phantasca.
Males and eggs of Arumatia gen. nov. are completely different from those of Echetlus, Candovia and other related Old-World taxa. For example, males of Arumatia gen. nov. lack granules and tubercles on the body, have a relatively longer and thinner body that is especially evident in the metathorax, and have thinner cerci and an asymmetric poculum. Eggs of Arumatia gen. nov. are smooth, lacking the strongly rugose texture of those of Echetlus and Candovia and have a longer and narrower micropylar plate. Although the females of Arumatia Ghirotto gen. nov. may superficially resemble those of Echetlus and Candovia, the overall morphology and proportions of the body and legs readily distinguish them from females of these Old-World taxa (Paul Brock, pers. comm., 2022).
Key to species of Arumatia gen. nov.
Females
1. Median segment as long as metanotum; cerci longer than terga IX and X combined; praeopercular organ absent. ...................................................................................................................................... 2
– Median segment shorter than metanotum; cerci as long as terga IX and X combined or shorter; praeopercular organ present or absent ............................................................................................... 3
2. Cerci shorter than terga VIII–X combined but longer than IX and X combined; subgenital plate reaching only half the length of tergum X; Brazil (São Paulo, Minas Gerais, Paraná, Distrito Federal, Goiás) and Paraguay (Paraguarí) ................................... A. dubia (Caudell, 1904) gen. et comb. nov.
– Cerci about as long as terga VIII, IX and X combined; subgenital plate exceeding tergum X; Brazil (Mato Grosso) ............................................................ A. fulgens (Zompro, 2004) gen. et comb. nov.
3. Median segment slightly shorter than metanotum; cerci around the same length as of terga IX and X combined; subgenital plate reaching around ¾ the length of tergum X; praeopercular organ present; Brazil (Tocantins) ..................................................................... A. aramatia Ghirotto gen. et sp. nov.
– Median segment distinctly shorter than metanotum; other combination of characters ..................... 4
4. Head oval in dorsal view, wider than pronotum; mid and hind tibiae with three stronger spiniform setae at the end of all carinae; cerci robust, only slightly longer than tergum X; subgenital plate reaching around ¾ the length of tergum X; praeopercular organ present and small; Brazil (Goiás) ......................................... A. crassicercata Ghirotto, Crispino & Engelking gen. et sp. nov.
– Head about as wide as pronotum or narrower in dorsal view; setae on carinae of tibiae otherwise; cerci significantly longer than tergum X, only slightly shorter than terga IX and X combined; praeopercular organ absent or present ............................................................................................... 5
5. Head laterally convex, about as wide as pronotum in dorsal view; apical region of carinae of tibiae with uniform setae; epiproct short; subgenital plate reaching posterior margin of tergum X; praeopercular organ absent; Brazil (Rondônia), very likely Bolivia …............................................... ...................................................................... A. anyami Ghirotto, Crispino & Neves gen. et sp. nov.
– Head significantly elongate, parallel-sided; all three ventral carinae of all tibiae with sessile apical spine; epiproct prominent and elongate; subgenital plate reaching around ¼ to ⅓ the length of tergum X; praeopercular organ present.......................................................................................................... 6
6. Head 2 × as long as wide; all terga smooth; epiproct about half the length of tergum X, with round apex; praeopercular organ prominent and lobed; cerci as long as terga IX and X combined; Brazil (Minas Gerais) .......................................................................... A. motenata Ghirotto gen. et sp. nov.
– Head 2.3× as long as wide; tergum VI with two tubercles; epiproct more than half the length of tergum X, with roundly acute apex; praeopercular organ present but small; cerci shorter than terga IX and X combined; Brazil (Bahia).......................................... A. diamante Ghirotto gen. et sp. nov.
Males
1. Head with convex sides in dorsal view; mid and hind tibiae with one to few stronger spiniform setae at end of all carinae; tergum IX longer than X; poculum elongate and conical, pointed in lateral view; tergum X without lateral expansions; thorn pads restricted to ventral area of posterior margin of tergum X; Brazil (Tocantins)................................................ A. aramatia Ghirotto gen. et sp. nov.
– Head with parallel to concave sides in dorsal view; ventral carinae of all tibiae with sessile apical spine; tergum IX, about same length as X; poculum shortened and round in lateral view; tergum X with flat lateral expansions bent downwards; thorn pads reaching ventral area of lateral expansions; Brazil (Minas Gerais) ............................................................... A. motenata Ghirotto gen. et sp. nov.
description: Published as part of Ghirotto, Victor Morais, Crispino, Edgar Blois, Engelking, Phillip Watzke, Neves, Pedro Alvaro Barbosa Aguiar, Góis, Júlia de & Chiquetto-Machado, Pedro Ivo, 2022, Arumatia, a new genus of Diapheromerinae stick insects (Insecta, Phasmatodea) from Brazil, with the description of five new species and a reassessment of species misplaced in Australian genera, pp. 1-85 in European Journal of Taxonomy 827 (827) on pages 4-9, DOI: 10.5852/ejt.2022.827.1849, http://zenodo.org/record/6795618