Laberiini, a new tribe of Tropiduchidae planthoppers from Madagascar (Hemiptera: Fulgoroidea)

. The tropiduchid monotypic genus Laberia Stål, 1866, endemic to Madagascar, is placed in a new tribe of its own Laberiini trib. nov. The tribe is placed in the subfamily Elicinae, and can be distinguished from other representatives of the subfamily by the unique combination of morphological characters of the head, tegmina, legs and genital structures. The genus Laberia and its only species Laberia palliata Stål, 1866 are redescribed, chresonymy is presented and nomenclatorial questions are clarified. Distributional data from Madagascar and doubtful presence of the taxon in Mauritius are discussed. Taxonomic content of Elicinae is briefly discussed.


Introduction
Tropiduchid planthoppers (Insecta Linnaeus, 1758, Hemiptera Linnaeus, 1758, Fulgoromorpha Evans, 1946 are most often found associated with herbaceous and woody dicotyledons, palms, grasses, rushes and ferns (Fennah 1982) in more than 20 plant orders (Bourgoin 2022), while several species are known to feed on crop plants (Fennah 1982; Bartlett et al. 2018). They are mainly present in the warmer regions of the globe (Fennah 1982), and distributed between the north temperate and the south subtropical bioclimatic zones (Bourgoin 2022). In these regions, they have adapted themselves to habitats ranging from rainforests to macchia and semideserts (Fennah 1982). Currently, the family Tropiduchidae Stål, 1866 includes 197 genera (7.8 % of the planthopper genera) and 680 species (4.9 % of the species), forming a medium-sized family within the Fulgoromorpha. They belong to the group of the 'higher Fulgoroidea' with 9 other families, whose monophyly and relationships have yet to be verified using phylogenetic analytical tools (Bartlett et al. 2018).
Despite this important taxonomic activity, the history of the family and its classification remains relatively simple (Fig. 1) compared to that of other planthopper families (e.g., Issidae Spinola, 1839; Wang et al. 2016). Tropiduchidae was first recognized by Stål (1866) and subsequently divided into Tambiini Kirkaldy, 1907 andTropiduchini Stål, 1866. The first elaborated classification of the family was provided by Melichar (1914) who divided it into six groups -Hiraciini Melichar, 1914, Peggionini Stål, 1866, Paricanini Melichar, 1914, Tripetimorphini Melichar, 1914, Tambiniini Kirkaldy, 1907, andTropiduchini Stål, 1866; the latter divided into Alcestini Melichar, 1914, Catulliini Melichar, 1914and Tangiini Melichar, 1914. After a few modifications by Muir (1923Muir ( , 1930 and cataloguing by Metcalf (1954), the family was thoroughly reviewed by Fennah (1982) who divided it into 16 tribes. Several other extant and extinct tribes were successively added and, finally, Gnezdilov (2013) divided the family into two subfamilies, Tropiduchinae and Elicinae, the latter being the topic of this paper. With the result of this paper, the family now accounts for 25 tribes, the relationships of which still remain to be totally investigated on a phylogenetic basis, using both morphological and particularly molecular analyses, for which sequenced taxa remain very few compared to the diversity of the family.

Material and methods
The nomenclature of the fore wing (tegmen) follows the interpretation proposed by  and Stroiński (2020). Antennal structures were named following Stroiński et al. (2011). The terminology of the genitalia follows Bourgoin (1988) and Bourgoin & Huang (1990) for the male and Bourgoin (1993) for the female.
To reveal genital structures, the whole abdomen of a specimen examined was cut off and cleared for 30 min in a warm (50°C) 10 % potassium hydroxide (KOH) solution with a few drops of black chlorazol (CAS No. 1937-37-7) for staining the ectodermic genital structures, based on the method introduced by Carayon (1969). Dissections and cleaning of the genital structures were carried out in distilled water.
Final observations were made in glycerol using Olympus SZH10 and SZX10 stereo microscopes. The photographs of the habitus and internal structures were taken using a stereo microscope Leica MZ 16 with IC3D camera. Final images were adjusted using Helicon ver. 5.0 software and Adobe Photoshop (ver. 7.0). The SEM photographs of uncoated specimens were taken in the Laboratory of Scanning Microscopy, MIZ PAS (Warsaw), using a scanning electron microscope HITACHI S-3400N under low vacuum conditions. The different proposed taxonomic rearrangements are displayed according to standardized models proposed by Bourgoin (2022),  and in other tropiduchid papers: Gnezdilov et al. (2016), Bourgoin et al. (2019Bourgoin et al. ( , 2021, Bourgoin & Wang M. (2020).

Measurements and abbreviations
Measurements were taken with a micrometer. The following measurements, ratios, and their abbreviations were used in this study: Total length = length of specimen from head apex to tegmina apex (in dorsal view) A/B = width of vertex measured at anterior margin / length of vertex measured at midline C/E = width of frons at upper margin / length of frons at midline D/E = maximum width of frons / length of frons at midline F/B = length of pronotum at midline / length of the vertex at midline G/F = length of mesonotum / length of pronotum at midline G/B+F = length of mesonotum / cumulative length of vertex and pronotum at midline G/H = length of mesonotum at midline / width of mesonotum between lateral angles I/J = length of tegmen measured from the base to the apical margin in median portion / width of tegmen measured at the widest part Label information of all specimens examined are provided verbatim with each line separated by a slash (/) and each label given in quotation marks ("").
The administrative division of Madagascar follows the results of the Malagasy constitutional referendum in 2007(HCC 2007.
The material studied is deposited in the following collections:

Tropiduchidae content and classification
Including fossil tribes, Tropiduchidae is currently divided into 2 subfamilies and 25 tribes including the one described here (some of them subdivided into subtribes), as a result of several recent transfers and changes of the status of several taxa -genera, subtribes and tribes (Gnezdilov 2007(Gnezdilov , 2012a(Gnezdilov , 2013Fletcher 2008;Stroiński & Gnezdilov 2009;Gnezdilov et al. 2016) (Fig. 2). A phylogenetic analysis was recently provided for Tropiduchini (Wang R.R. et al. 2017), but it remains the only one. The phylogeny of the family, including questions of its monophyly in the context of its current definition and content, as well as questions about the relationships of all these subunits (tribes and subtribes) to each other remain unanswered. An updated history of the classification of Tropiduchidae is summarized in Fig. 1.
In the subfamily Elicinae , taxa were originally put together to form the tribe Elicaini  in the family Lophopidae Stål, 1866 by  379) ( Fig. 2A-B). It comprised six genera: Elica Walker, 1857, Micromasoria Kirkaldy, 1904, Padanda Distant, 1906, Zeleja Melichar, 1915, Epiptyxis Gerstaecker, 1895and Ivinga Distant, 1911. The genus Padanda Distant, 1906(type species Padanda atkinsoni Distant, 1906 first synonymized under Cixiopsis Matsumura, 1900(Matsumura 1914 was resurrected by Melichar (1915: 382) and successively transferred to Dictyopharidae Spinola, 1839 (Muir 1930), Issidae (Muir 1934), Dictyopharidae (Metcalf 1946) and Tropiduchidae: Cixiopsini Fennah, 1982by Fennah (1982. The genera Zeleja  and Epiptyxis Gerstaecker, 1895 remain within the Lophopidae in the tribe Menoscini (Emeljanov 2013 and genus Ivinga Distant, 1911 was first transferred to Issidae by Fennah (1954: 457), as a subgenus of Trienopa Signoret, 1860 and later synonymized with Trienopa in the Tropiduchidae: Trienopini Fennah, 1954(Gnezdilov 2007. The generic name Micromasoria was proposed by Kirkaldy (1904: 279)  More recently, Gnezdilov (2007: 295) transferred the subtribe Gaetuliina Fennah, 1978 Fig. 2B blue arrows indicate when a genus was first classified in the current classification of the tribe, red arrows indicate when a genus was first wrongly placed in the tribe, then withdrawn for another tribe (left red arrow). Last column in grey provide the corresponding reference and basic information. Schmidt, 1912, Paraphilatis Melichar, 1914, Parathiscia Melichar, 1901and Pseudothiscia Schmidt, 1912. While the first genus currently remains incertae sedis within Fulgoroidea Latreille, 1807, the last four genera were grouped a year later (Gnezdilov 2013) to form a new tribe Parathisciini Gnezdilov, 2013. In this same paper he transferred Elicina from Nogodinidae, Bladinini into the Tropiduchidae, and concurrently synonymized (Gnezdilov 2013. Finally, he grouped ( However, the attribution of the extinct tribes Patollini and Austrini to Elicinae was not discussed by Gnezdilov (2013: 182). The main characters present in the female genitalia are not available because only male fossils are available in both tribes, and the absence of a nodal line alone is insufficient to accredit them to Elicinae. However, according to the very regular basal conformation of the tegmina venation and late forking of the main veins (ScP+R, MP and CuA), particularly with first 2 transverse veins of cells C2 and C4 aligned (as prefiguring a nodal line), the densification of transverses in the second apical half of the forewing, the simple venation of the forewing, and the short vertex, wider than long, it seems more appropriate to transfer Austrini from Elicinae to Tropiduchinae. Conversely, the non-regular basal venation in Patollini supports keeping this tribe within Elicinae.

Content and distribution
Currently, Elicinae includes 46 genera and 158 species and Elicini remains the most diverse tribe within the subfamily with 37 genera (1.5% of the Fulgoromorpha) and 143 species (1% of the Fulgoromorpha) (Bourgoin 2022; Fig. 2). Due to its complex history chronologically listed here, that we complete, we provide a graphical historical synopsis of the generic composition of the tribe ( Fig. 2A-B).
The fossil taxa of Elicini are known from the Eocene Baltic amber (Tritophania Jacobi, 1938)

Diagnosis
Head capsule narrower than thorax, projecting in front of eyes. Pedicel with plate organs on the whole surface reaching to its base. Rostrum long, ending between metacoxae. Tegmina broad, extending far beyond abdomen, held flattening tectiform, with their ventral faces not facing each other; costal area present and wide, with reticulate venation; nodal line not materialized. Hind tibia with 5-7 lateral spines. Metatarsal apical teeth asymmetrical. Male gonostyli symmetrical, not fused. Female: gonoplacs flat quadrangular, wide, without apical marginal teeth. Gonapophyses IX with a long, lateral, digitated process. Anal tube short, ring-shaped.
A new simplified key to higher taxa of Elicinae to accommodate the new tribe Laberiini trib. nov. is proposed here:
Tegmina (Figs 9B-F, 10A-D). Ratio I/J = 1.86-2.02; membranous, with dense network of veins and veinlets. Costal margin curved at base, arcuate to anteroapical angle; anteroapical angle widely arcuate, posterior margin arcuate, posteroapical angle widely obtuse; tornus straight; apex of clavus reaching ⅔ of tegmen length. Costal area present, wide, with apex reaching almost to ⅔ of tegmen length, merely basad of apex of clavus; costal area with prominent, reticulate network of veinlets. Basal cell rounded, slightly longer than wide. Stems ScP+R, MP and CuA leaving basal cells separately, in ScP+R→MP→CuA forking sequence on corium. Stem ScP+R with short stalk, shorter than basal cell, both branches ScP+RA and RP with few furcations, together with veinlets resulting in reticulate pattern, ultimate terminal of RP reaching anteroapical angle. Common stalk of MP about as long as basal cell, both branches MP 1+2 and MP 3+4 with number of furcations, together with veinlets resulting in reticulate pattern, the earliest terminal of MP 1+2 reaching anteroapical angle, the ultimate terminal of MP 3+4 exceeding posteroapical angle, reaching tornus. Common stem CuA distinctly longer than basal cell; branch CuA 1 weaker, with a few furcations, reaching tornus with three terminals, branch CuA 2 stronger, parallel to claval suture and vein CuP, reaching margin with single terminal. Claval suture and vein CuP distinct. Claval veins Pcu and A 1 fused in basal half of clavus length, joined vein Pcu+A 1 reaching apex of clavus; irregular veinlets between CuP and Pcu present. Costal cell narrow, with a few veinlets between stems Pc+CP and ScP+RA. Nodal line not materialized. Chitinized pterostigmal area absent. Veinlet icu present, connecting CuA 2 and apex of clavus. Veins with short, scarce setae on ventral surface.
Hind wing. Membranous, costal margin slightly curved at base, then almost straight, slightly concave at level of wing coupling apparatus, anteroapical angle widely rounded, apical margin distinctly curved, posteroapical angle widely rounded, anal lobe widely rounded. Basal cell slightly longer than wide, stems ScP+R and M leaving basal cell with a short common stalk. Stem ScP+R forked at level of wing coupling apparatus, ScP+RA 1 reaching margin distinctly basad of anteroapical angle, with 3 terminals; single rarp veinlet present. RP forked apicad of transverse veinlet rp-mp, about at the level of ending RA vein; RP with 4-6 terminals reaching margin basad of and at anteroapical angle. Transverse veinlets rp-mp 3-4. Stem MP forked usually about level of first fork of RP, with 4-5 terminals, single imp vein present between MP 1+2 and MP 3+4 . Stem CuA forked distinctly basad of stem ScP+R forking, before half of wing, multifurcation with 11-16 terminals and with 10-12 icu veins. Stem CuP single, stem Pcu subparallel to CuP in basal portion, apically curved towards CuP. Veins with short scarce setae on ventral surface.
Coloration (Figs 3A-C, 4A-F, 5). General coloration green. In dry and older specimens, general coloration reddish-brown or brown. Hind wing membranous, transparent, with one dark, round spot on anal area. Abdomen in ʻfreshʼ specimens with orange tergites and sternites yellowish, yellowish-brown to brown in oldest specimens.

Note
The genus Laberia was described by Stål (1866), based on single female specimen labelled as originating from Mauritius (Fig. 3D), as a new genus belonging to Ricaniidae. This seems to be a case of mislabelling, as since the original description it was never reported on Mauritius, and all specimens available came from Madagascar. Melichar (1898: 296) moved this genus to Nogodinidae, and Fennah (1978: 118) placed it in the tribe Bladinini Kirkaldy, 1907, subtribe Gaetulina Fennah, 1978 The subsequent changes in placement of Laberia in Tropiduchidae resulted from taxonomic views and opinions concerning Gaetuliini (see above). However, the type material of Laberia has never been re-examined since its description and its characters and taxonomic status needed to be reconciled with the taxonomic changes that took place around the families Nogodinidae-Tropiduchidae and their respective delimitation. A few additional specimens of the species were found dispersed in various collections enabling this revisionary study that led to our separation of the genus into a new tropiduchid Elicinae tribe, Laberiini trib. nov. Additionally, during this study, we also discovered that another 'mythical' taxon from Madagascar, Perinetia reticulata , originally described as a species of a monotypic genus of the family Acanaloniidae Amyot & Serville, 1834, was conspecific with Laberia palliata Stål, 1866.
The generic name Perinetia was proposed by various authors several times for various species of animals. Currently, all these usages have been replaced by new names. Hence, the generic name Perinetia becomes again available for the purposes of taxonomy. However, the oldest usage of this name for a genus is now believed to be a junior objective synonym. All subsequent proposals with Perinetia as generic name have already been replaced.