Orthotylus, FIEBER AND ALLIED, 1858

Symonds, Celia L. & Cassis, Gerasimos, 2018, Systematics And Analysis Of The Radiation Of Orthotylini Plant Bugs Associated With Callitroid Conifers In Australia: Description Of Five New Genera And 32 New Species (Heteroptera: Miridae: Orthotylinae), Bulletin of the American Museum of Natural History 2018 (422), pp. 1-229 : 33-46

OVERVIEW OF ORTHOTYLUS FIEBER AND ALLIED TAXA

REVIEW OF THE TAXONOMY OF ORTHOTYLUS : Generic concepts in the tribe Orthotylini are a work in progress. There are currently 222 orthotyline genera, with Orthotylus Fieber the nominotypical and most speciose genus of the tribe ( Cassis and Schuh, 2012). Orthotylus comprises 392 described species ( Schuh, 2002 –2013; Polhemus, 2013) and is found in all major biogeographical regions of the world. The centers of Orthotylus diversity are the Western Palearctic and Hawai’i (distribution summarized in table 3). Polhemus (2002; 2004; 2011; 2013) described nearly 100 new species of Orthotylus from Hawai’i, and found no basis for erecting a separate genus for their inclusion.

There are currently 16 junior synonyms of Orthotylus , with all but one described from the Palearctic region ( Schuh, 2002 –2013). Fieber (1858) first described Orthotylus , with O. marginalis designated as the type species. Reuter (1875) relegated Melanotrichus Reuter to a subgenus of Orthotylus and he was the first to adopt a subgeneric classification. In his study of British Orthotylus, Southwood (1953) recognized four subgenera based primarily on the morphology of the endosomal (as vesical) spicules and parameres. Wagner (1973), in an overview of Mediterranean Orthotylus species , recognized six subgenera, including those of Southwood (1953). More recently, Yasunaga (1999) erected Orthotylus (Yamatorthotylus) Yasunaga from the eastern Palearctic, Ehanno and Matocq (1990) described the subgenus Orthotylus (Parapachylops) Ehanno and Matocq from the western Palearctic, and Linnavuori (1994) described Orthotylus (Ericinellus) Linnavuori from the Afrotropical region (see table 4). Chinese authors have also followed this subgeneric approach ( Liu and Zheng, 2014).

Elsewhere in the world, subgenera have not been used in the classification of Orthotylus species. The Nearctic, Neotropical, and Australasian (including Hawaiian) species of Orthotylus have not been assigned to subgenera and often assigned to Orthotylus on a provisional basis ( Carvalho and Fontes, 1973; Carvalho and Schaffner, 1973; Carvalho, 1985; Kerzhner and Schuh, 1995; Schuh, 1995; 2002 –2013; Polhemus, 2002; 2004; Forero, 2009; Polhemus, 2011; 2013). Van Duzee (1916) and Knight (1968) described most Orthotylus spe- cies from North America. The South African species are few, scarcely documented, and mentioned only in general terms by Schuh (1974).

American workers recognized Melanotrichus as a valid genus ( Henry and Wheeler, 1988; Henry, 1991; Schwartz and Scudder, 2003). In contrast, Palearctic workers have traditionally treated it as a subgenus of Orthotylus ( Southwood, 1953; Wagner, 1973; Ehanno and Matocq, 1990; Linnavuori, 1994; Yasunaga, 1999). Knight (1927, 1968) described the majority of North American Melanotrichus species. Schuh (1995, 2002 –2013) treated Melanotrichus as a junior synonym of Orthotylus on a worldwide basis pending revision. Kelton (1979a) also found the North American species assigned to Melanotrichus ( Knight, 1927, 1968) to be paraphyletic, and transferred 15 species to a new genus Brooksetta Kelton (1979b) , after comparison with the Palearctic type of Melanotrichus , Orthotylus flavosparsus (Sahlberg) . Carvalho (1985) described South American species of Melanotrichus , however, these taxa are very different morphologically from the Palearctic taxa. Kerzhner and Schuh (1995) transferred these species to Orthotylus . Recently, Yasunaga and Duwal (2017) recognized 11 Asian species with Oriental and Palearctic distributions as congeners of Melanotrichus (after Henry and Wheeler, 1988), including one new species and 10 species transferred from Orthotylus , while also recognizing the need for a revision of Melanotrichus worldwide. In this case, the recognition of Melanotrichus as a valid genus represents an alternative classification that requires a much broader study than we present in this work.

Schuh (1974) listed nearly 40 genera as part of his suprageneric Orthotylus group, including Blephardiopterus Kolenati, Hadronema Uhler , Lopidea , Heterotoma Le Peletier and Serville , Pseudoloxops Kirkaldy , and Pseudopsallus . The above condition of the endosomal spicules applies to many orthotyline taxa worldwide, including the Neotropical genera Biobiocoris Carvalho and Chileria Carvalho ( Forero, 2009) We examined in detail the genitalic characas well as species of the recently described Aus- ters of the type species of Orthotylus , O. margitralian genera Acaciacapsus , Granitohyoidea , nalis Reuter, and putatively related Palearctic Harveycapsus , Myrtlemiris , and Naranjakotta species. These species possess pale hairlike sim- ( Cassis et al., 2010; Cheng et al., 2012a; Cassis ple setae, large and projecting parameres, the and Symonds, 2014a, 2014b, 2016). left paramere has a rounded and elongate sen-

TAXONOMIC CHARACTERS WITHIN ORTHOTY- sory lobe and elongate and angulate apophysis LUS: To assign the callitroid-inhabiting species to with a small, recurved apical hook, and the genus, we investigated the characters used by right paramere is roughly C-shaped. They also previous authors in establishing genera of possess two endosomal spicules, with the PES Orthotylini , including Orthotylus and its infrage- and DES arcuate and subequal in length, with a neric groups, as well as making novel observa- basal branch on DES and a basal keel attached tions of exemplar taxa from regions extralimital to the basal branch (fig. 7, 8C–E). Also, the to Australia. Our approach was first to gain a genital opening of the pygophore is large and detailed understanding of the key characters of there is a small, spinelike left tergal process Orthotylus . The genus is hyperdiverse, the only (figs. 7, 8A) and the ventral margin of the pygocosmopolitan genus in the tribe, and likely a con- phore is straight. The number, form, and posivenience group; as such, numerous genus groups tion of the endosomal spicules in relation to the are likely to overlap. Orthotylus is a highly het- secondary gonopore vary in infrageneric groups erogeneous genus morphologically, based on the of Orthotylus (table 4). In Orthotylus marginalis species currently placed within it. The characters and related Palearctic species, the endosomal that have been used in the infrageneric classifica- spicules are often branched and usually serrate tion of Orthotylus include: (1) relative lengths of on the distal margins. PES is left dorsolateral to the antennae; (2) eye to vertex ratio; (3) body the secondary gonopore but also extends to the color (yellow-green to dark brown, sometimes ventral surface, at the base of this spicule, with patterning); (4) dorsal vestiture type (simple sheathing the secondary gonopore, whereas setae or a mix of simple and scalelike setae) and DES is dorsad to the secondary gonopore and color; (5) pronotum shape; (6) pygophore (geni- extends to the right dorsal side of the secondary tal opening, presence of absence of tergal pro- gonopore (fig. 8C–E). A key characteristic for cesses); (7) paramere shape; (8) aedeagus Orthotylus is that the basal branch on DES is (positioning, shape, branching, and substructure connected by a small bridge and the small, of the endosomal spicules); and (9) female inter- sclerotized basal hook is connected to that basal ramal lobes (= K structures sensu Slater, 1950). branch (fig. 7; Southwood, 1953). The female

The key characters differentiating Orthotylus genitalia of O. marginalis has a divided intersubgenera are summarized in table 4. The paramere ramal sclerite, which are individually spinifer- and endosomal spicule structure is described in ous basally and at the medial angle, with the detail in a homologous approach to our character- medial region extending in a triangular shape ization of the Australian Orthotylini . The following beyond the margin of the interramal sclerites discussion gives a summary of key characters by (fig. 10C). The interramal lobes are divided at subgenus in the Palearctic region, and Orthotylus the apex and attached narrowly at the base, latsensu lato in other biogeographic regions as well as erally on the interramal sclerites, and are the Hawaiian Islands, and highlights examples of strongly spinose (fig. 10C). The ventral labiate some inconsistencies within the subgeneric groups. plate is broadly spinose (fig. 10A) and the ves- FIG. 7. Male genitalia and habitus of Orthotylus spp. Views dorsal unless otherwise stated. Scale bars = 0.1 mm, unless otherwise marked. tibulum is strongly sclerotized (fig. 10B), and subquadrate mediolateral lobes are present mesially on the dorsal labiate plate (fig. 10B).

Although there are repeated paramere and endosomal spicule patterns within Orthotylus , they are not defining for the described subgenera as presented. Within the nominotypical subgenus of Orthotylus there is considerable variation in the structure of the two endosomal spicules, which corresponds in part to differences in paramere structure as well ( Southwood 1953). Most species assigned to the nominotypical subgenus have branched and serrate endosomal spicules, some differing from Orthotylus marginalis (table 4), which Southwood (1953) recognized in his subgeneric species groups. In some species, such as Orthotylus virescens (Douglas and Scott) , O. ade- nocarpi (Perris), O. viridinervis (Kirschbaum) , and O. boreellus (Zetterstedt) , the endosoma has a slender unbranched ventral spicule (= PES) and a similar bifurcate, basally branched dorsal spicule (= DES) (see Southwood, 1953: figs. 97–110). Wagner (1973) also noticed this and transferred species to other Orthotylus subgenera.

Wagner (1973) provided a redescription of Orthotylus in his study of western Palearctic species, but in the main most of his characters are general to the subfamily Orthotylinae , except for the presence of endosomal spicules (as two chitin bands) and the presence of interramal lobes (as K structures). He then used external characters to define subgenera, including dorsal vestiture and secondarily supported by the structure of the endosomal spicules.

Yasunaga (1999: figs. 7–25) reported that Japanese species of Orthotylus (Orthotylus) have three endosomal spicules, although it is likely there are two spicules in some species (based on illustrations, the two dorsal spicules appear to be connected by a basal branch), which allies them with O. marginalis . In contrast, the male genitalia of Orthotylus japonicus Yasunaga are significantly different and putatively do not belong to the nominotypical subgenus, possessing three discrete endosomal spicules and differently configured parameres ( Yasunaga, 1999: figs. 26–30). Orthotylus (Orthotylus) nassatus Fabricius appears to be related to Orthotylus (Kiiorthoty- lus) gotchi Yasunaga ( Yasunaga, 1999: figs. 46–49), which has a distinctive left paramere hook and dorsal subbasal lobe, a similar flattened and distally serrate right paramere, and a greatly divided ventral spicule (PES); in addition, the dorsal spicule (DES) of both these species is without a basal branch or obvious basal keel (see Wagner, 1973: figs. 482A, E, 483A). Illustrations of African Orthotylus (Orthotylus) species ( Linnavuori, 1975; 1994) also suggest that they are distantly related to Orthotylus marginalis .

Numerous Palearctic species assigned to Orthotylus (Melanotrichus) are robust, possess hairlike and scalelike setae, and the parameres and two simple endosomal spicules define the group. Wagner (1973; fig. 503G) described one or more tergal processes on the genital capsule of the pygophore of these taxa, which are typically elongate and fingerlike, and project medially from right of centre. This is similar to the Palearctic species Orthotylus ericetorum (Fallén) . The African species assigned by Linnavuori (1994) to Orthotylus (Melanotrichus) have in common the vestiture and parameres typical of western Palearctic species (including the type species of the subgenus, O. flavosparsus Reuter ). They also have distinct differences, including a small phallotheca with a spiniferous patch distally, no endosomal spicules, a greatly elongate secondary gonopore, the pygophore without any tergal processes (also noted in North American species by Kelton, 1979a), and a distinctive pattern of scalelike setae on the pygophore ( Linnavuori, 1975; 1994). Asian species with Oriental and Palearctic distributions now treated as Melanotrichus possess a distinct character set including: a small body size and eyes, both dark simple setae and scalelike setae, small parameres, and a simple endosoma, without endosomal spicules ( Yasunaga and Duwal, 2017). On the basis of our observations and review of the literature, the absence or presence of endosomal spicules among these taxa brings into question the monophyly of Melanotrichus , regardless of its ranking, and the transfer of all the species by Yasunaga and Duwal (2017). We have considered character systems for only some of the species previously assigned to Melanotrichus at generic and subgeneric levels here, but not exhaustively, which is beyond the scope of this work. We are in agreement that the definition of Melanotrichus requires a comprehensive review.

The subgenus Orthotylus (Neopachylops) Wagner comprises species with complex serrate endosomal spicules and a combination of setal types, and at least two natural groups, not necessarily related, for the species included by Wagner (1973). Species such as Orthotylus adenocarpi bear little resemblance in paramere and endosomal spicule structure to those of the type Orthotylus concolor (Kirschbaum) . The male genitalia of Orthotylus ericetorum , the type of the junior synonym Litocoris Fieber appear to be similar to Orthotylus (Neopachylops) Wagner , but there are differences in the pygophore and parameres between these subgenera. Linnavuori (1994) erected the subgenus Orthotylus (Ericinellus) for two species, both of which occur in Africa, and these also resemble Orthotylus ericetorum , differing in the ecarinate vertex and simple aedeagus, which is without spicules.

Southwood (1953) erected the monotypic subgenus Orthotylus (Pinocapsus) Southwood (type: Orthotylus fuscescens (Kirschbaum)) based on two elongate, unbranched and smooth endosomal spicules and characteristic parameres. Subsequently, Wagner (1973) placed another two species in this subgenus, both of which have two similar endosomal spicules, but the parameres of only one resemble those of the type species ( Wagner, 1973: fig. 472). Southwood (1953) also erected the subgenus Orthotylus (Neomecomma) , for the Palearctic species, Orthotylus bilineatus (Fallén) . Its genitalia are undoubtedly distinct, and it is unlikely to be closely related to Orthotylus sensu stricto.

The type species of the monotypic subgenus Orthotylus (Yamatorthotylus) Yasunaga , Orthotylus xanthopoda Yasunaga , has large parameres that project beyond the genital opening of the pygophore (as in Orthotylus marginalis ) and there is a bifid left tergal process on the genital opening of the pygophore. The ventral margin of the genital opening is weakly convex and there are short, dark spinelike setae proximate to the opening. Yasunaga (1999: figs. 54–56) reported that the two endosomal spicules are bifurcate, but their configuration is difficult to discern from his illustration. Orthotylus is the most diverse group of true bugs in the Hawaiian Islands, and are thought to represent multiple insular radiations that putatively track different plant families ( Polhemus, 2011). Polhemus (2002) mentions that the paramere shapes are homologous among species found on host plants in the same genus or family. There is much congruence in the shapes of the parameres across the 100 or so species, as in the structure of the phallotheca and endosomal spicules. Key characters of these Hawaiian species are: (1) relatively small, elongate ovoid shape, mixed green-brown to black species, often bicolored (e.g., Orthotylus tantali , fig. 7); (2) simple setae on the dorsum; (3) short head in front of the eyes; (4) robust tibial spines on the legs; (5) simple transverse pygophore, without tergal processes; (6) simple parameres, with the left paramere L-shaped, with a weakly to moderately expanded and rounded sensory lobe, and the right paramere club shaped or L-shaped, with both parameres, particularly the right, with a clump of elongate setae on the outer distal lobe (e.g., figs. 7, 9F); (7) endosomal spicules mostly with smooth margins, divided into many branches, often with connecting membrane, and when serrate confined to the apices; and (8) phallotheca usually simple and open (fig. 7). Polhemus (2002; 2004; 2011; 2013) did not homologize the endosomal spicules nor provide detailed description of their substructure.

We examined in detail the male genitalia of the Hawaiian species, Orthotylus tantali Polhemus , and its L-shaped left and right parameres, pygophore, and phallotheca are relatively simple (fig. 7). The ventral margin of the genital opening of the pygophore is almost straight and the parameres are folded over each other and are situated just inside the ventral margin, beneath the aedeagus and phallotheca, both of which protrude only slightly (fig. 9D–F). Two distinctive endosomal spicules are present, which we interpret as a simplified PES and complex DES (fig. 7). PES is positioned in the left lateral position and DES is right dorsal, with PES relatively narrow and bifurcate, with short and elongate branches. DES is large and broad, with five branches emanating from a membranous midsection, and possesses a distinctive basal keel. Both spicules have smooth margins and are interspersed with membrane, as seen in the Australian orthotyline genus Myrtlemiris , although in the latter genus there are three distinct endosomal spicules ( Cheng et al., 2012a). The female of O. tantali has a lightly sclerotized opening of the vestibulum, in comparison with Orthotylus marginalis , and a spiniferous ridge or mediolateral band (mlb) along the posterior margin of the dorsal labiate plate (fig. 10E). The interramal sclerites appear to be an undivided plate across the posterior wall, obscured and covered by the interramal lobes, which are quadrate, uniformly spiniferous, and broadly fused across the sclerite base (fig. 10F).

The North American Orthotylus species are most commonly found on willows and poplars and, with the South African species (which feed on Acacia spp. ), are the least described morphologically within the genus. Van Duzee (1916) described taxa of three main body forms—small, green, and moderately elongate; medium sized, pale, and ovoid; and larger, dark, and elongate species. He also was the first author to use the morphology of the parameres in the classification of Orthotylus . The Nearctic species of Orthotylus possess one or two spicules ( Asquith and Lattin, 1993). We examined one of these species, Orthotylus cuneatus Van Duzee , which is distinctly different from the Palearctic and Hawaiian congeners. They possess a single endosomal spicule, which we interpret as DES (also see Asquith, 1991; Schwartz, 2011), that sheaths the secondary gonopore dorsally, is divided toward the base with two serrate branches, and does not possess a keel (fig. 7). The phallotheca is very simple and opens broadly, without enclosing margins (fig. 7). While this species is large and elongate, with large eyes (fig. 7), the abdomen is short and the male genitalia are small overall (fig. 7). This combination of characters is also seen in some Australian Orthotylini , for example, Ngullamiris whadjuk , described in this work, has a cup-shaped ventral margin of the pygophore (figs. 7, 9A–C), parameres that sit inside the ventral margin of the genital opening of the pygophore (fig. 9A, B), and the ventral surface of the pygophore has small spines (fig. 9C). In addition to the characters above, the male genitalia of O. cuneatus differs from Orthotylus marginalis in the possession of a simple opening of the phallotheca and simpler parameres (fig. 7). The left paramere is a curved L-shape with a rounded and unexpanded sensory lobe, tapering apophysis, and acuminate apex. The right paramere is club shaped with a small apical flange, which is also seen in species of callitroid-inhabiting Orthotylini . The female genitalia of Orthotylus cuneatus is also small in comparison with its body size, and the vestibulum opening is largely membranous, and at most very lightly sclerotized. On the posterior wall (fig. 10D), the interramal sclerites are joined at the base and without any spines, the medial region has a bulbous process rounded distally and does not extend beyond the margins of the interramal sclerites. The interramal lobes are small with pointed and medially curved apices, and fine spines uniformly distributed across the lobes (fig. 10D).

Kelton (1959) illustrated and described two species of American Orthotylus , O. notabilis Knight and O. ornatus Van Duzee. Both these species have similar paramere and endosomal spicule morphology, which is significantly different from O. cuneatus . He described four endosomal spicules, however, from the illustrations it appears these are two that are basally branched.

Neotropical Orthotylus species , like the Afrotropical species, have very complex and ornate endosomal spicules ( Carvalho and Fontes, 1973; Carvalho, 1985), and Forero (2009) described natural groupings within the genus. Characteris- tics of these species include the presence of two endosomal spicules, which are dorsal to the secondary gonopore. PES is simple and slender, with an apical branch, with smooth margins, and is positioned at the left dorsolateral to the secondary gonopore. DES is subequal in length to PES, with medial branching and at least two small subbranches, the margins are smooth, and it is positioned right dorsolateral to the secondary gonopore (see Forero, 2009: fig. 14A–D). Other supporting characters include the structures of the parameres, pygophore and pinched phallotheca ( Forero, 2009: figs. 14, 15). The South African Orthotylus species have been little documented and are highly variable, although natural groupings are apparent ( Schuh, 1974).

Many of the above characters in Orthotylus are also found in other Orthotylini genera. For example, Orthotylus marginalis has many characters that are also found in the callitroid-inhabiting Orthotylini such as: (1) the simple setae; (2) overall green body color; (3) the elongate ovoid body (fig. 7); (4) the left paramere roughly L-shaped, with an expanded sensory lobe, and elongate apophysis with a hooked apex (fig. 7); (5) the right paramere C-shaped (fig. 7); (8) the parameres large and everted from the pygophore in repose; (9) the genital opening of the pygophore having a straight ventral margin (fig. 8A, B), with a left lateral tergal process (figs. 7, 8A); and (10) phallotheca simple and large (fig. 7) extending beyond the genital opening of the pygophore in repose (fig. 8A). Similarly, the Australian species, Naranjakotta sidnica , which was previously placed in Orthotylus , shares many of these characters.

The above discussion focuses on genitalic characters, where considerable variation exists. It is also important to evaluate previous use of vestiture characters in the diagnoses of subgenera of Orthotylus (e.g., Southwood, 1953; Wagner, 1973; Linnavuori, 1994). There is little doubt that setal types are homoplasious in Orthotylus ( Polhemus, 2002) , but have not been consistently applied across the genus. For example, Orthotylus (Orthotylus) is generally diagnosed as having only simple hairlike setae, yet some species with scalelike setae have also been placed in the nominotypical subgenus (e.g., Orthotylus repandus Linnavuori and related Afrotropical species; Linnavuori, 1994). Also, the Orthotylus (Orthotylus) compactus species group contains species with and without scalelike setae, as well as simple setae of differing color ( Linnavuori, 1994). The presence or absence of mixed vestiture has been found to be genus defining in Australian orthotyline genera, such as Acaciacapsus and Naranjakotta , both of which have intermixed hairlike and scalelike setae, whereas Myrtlemiris has only hairlike simple setae ( Cheng et al., 2012a; Cassis and Symonds, 2014a, 2016). In Australian Orthotylini the color of scalelike setae can vary between species within a genus and in some cases even within a species, e.g., Naranjakotta myrtlephila Cassis and Symonds (2016) . Stonedahl and Schwartz (1986) also reported that different scalelike setae in the Orthotylini are important taxonomically.

As with most character systems in the Miridae , many are subject to convergence, particularly in the case of the male genitalic characters in Orthotylus and other genera of the Orthotylini , where there appears to be repeated evolution of paramere and endosomal spicule types. This is confounded by the largely regional studies of the tribe and nominotypical genus. However, this does not infer that they are of limited taxonomic value. On the contrary, the degree of diversification, particularly of the endosomal spicules, necessitates their use, but we argue for in-depth evaluation of their number, position, canting, and substructure.

AUSTRALIAN SPECIES PREVIOUSLY ASSIGNED TO ORTHOTYLUS: Four Australian species have been historically placed in Orthotylus ( Cassis and Gross, 1995) . These include: (1) Leptidolon australianus ( Carvalho, 1965) , which was originally in Orthotylus (Melanotrichus) . Subsequently it was transferred to the subfamily Phylinae based on illustrations of the male genitalia ( Schuh, 1995; Schuh et al., 2015). (2) Orthotylus eurynome Kirkaldy, 1902 , was described from New South Wales and Reuter (1900) incorrectly synonymized it with the European species Orthotylus ericetorum (Fallén) . We compared a female cotype of O. eurynome with O. ericetorum specimens and confirm them as separate species, the former being larger in size and more uniformly pale green color (cf. bright green), with translucent wing membrane (cf. dark gray) and larger eyes. We also examined unpublished male genitalic illustrations of Jose Carvalho of O. eurynome , which resembles Orthotylini sp. Scorpion Springs, which we used as an outgroup taxon in our phylogenetic analysis. (3) Orthotylus roseipennis Reuter was described from a female specimen ( Cassis and Gross, 1995) with the holotype housed in the Naturhistoriska Riksmuseet, Stockholm, Sweden ( Gustafsson, 2006; Cassis et al., 2012). Examination of the type photograph suggests that this species is allied to the Australian genus Myrtlemiris by the red coloration of the first antennal segment, orange head, and largely red cuneus ( Cheng et al., 2012a). It resembles Myrtlemiris astartephila Cheng, Mututantri, and Cassis , with the latter known from southwestern Western Australia, whereas O. roseipennis was recorded from northern Australia (no precise locality). This species needs further investigation to confirm whether it should be transferred to Myrtlemiris . Nonetheless O. roseipennis does not belong to the new callitroidinhabiting genera, and is retained within Orthotylus as incertae sedis. (4) Reuter (1905) placed Capsus sidnica Stål in Orthotylus ; the type is located at the University Museum (Zoology), Helsinki, Finland. It is a female in poor condition with the abdomen missing and the locality recorded as “Sydney.” Cassis and Symonds (2016) transferred this species to their new Australian genus Naranjakotta , based on the unique structure of the proximal endosomal spicule (PES) (see fig. 11, table 5).

GLOBAL PERSPECTIVE ON ORTHOTYLUS AND GENERIC CONCEPTS IN THE ORTHOTYLINI : Orthotylus is a diverse genus but is ill defined, and we regard it as a convenience group that is likely intermixed taxonomically with putatively related orthotyline genera. Furthermore, almost all studies on the genus and tribe have been regional in scope, and there are few case studies that test the monophyly of supraspecific taxa. Our study began with the discovery of numerous new species of callitroid-inhabiting orthotylines in Australia, collected during a continentwide survey program in Australia ( Cassis et al., 2007). We provisionally assigned these species to Orthotylus , based on their green coloration, complex elongate endosomal spicules, simple setae, and an L-shaped left paramere. On closer inspection, we found the male genitalia to be significantly different from those of Orthotylus marginalis , the type of the genus, and allied western Palearctic species ( Southwood, 1953; Wagner, 1973). In addition, we examined the literature on species assigned to Orthotylus from the Afrotropical (Linnavuouri, 1994), Oriental ( Yasunaga, 1999) and Neotropical ( Forero, 2009) regions, as well as Hawai’i ( Polhemus, 2002, 2004, 2011, 2013), and again found the genitalic characters to be fundamentally different.

Southwood’s (1953) British Orthotylus work is the early benchmark for studies on the genus and allied taxa. He explicitly recognized the importance of endosomal spicules (as vesical appendages), parameres, and female genitalic interramal lobes, in differentiating subgenera within Orthotylus . However, he was hesitant to raise these subgenera to generic rank based on internal characters, although he maintained the approach of classifying species into defined subgenera based in part on vesical types. As a result, he did not provide an overarching diagnosis for the genus.

Subsequently, Kelton (1959) in his comparative study of male genitalia of the Miridae , recognized the primary importance of the “vesica” in defining species and genera, in particular the secondary gonopore, ductus seminis, and associated sclerotized processes. His work was deliberately descriptive and a limited synthesis, and in the case of the Orthotylinae , he observed that the Orthotylini and Halticini shared the horseshoeshaped secondary gonopore. Within the Ortho- tylini, he recognized the presence or absence of sclerotized processes (spiculi or sclerites) associated with the “vesica” as distinctive at the species level and thus helpful for determining natural groupings of species. He also appreciated the value of the phallotheca in defining species. He examined 19 genera of which only two were Orthotylus species , and although he described fine details of the spicules he did not find any major trends in the morphology of the “vesica” among these taxa.

In recent decades mirid workers have examined in more detail the positioning and structure of the endosomal spicules in the Orthotylini . As part of this effort, authors have proposed hypotheses on the homology of the endosomal spicules ( Schwartz and Stonedahl, 1986; Stonedahl and Schuh, 1986; Stonedahl and Schwartz, 1986; Schwartz and Stonedahl, 1987; Asquith, 1991; Schwartz, 2004, 2011; Cassis, 2008; Forero, 2009; Cassis et al., 2010; Cheng et al., 2012a; Cassis and Symonds, 2014a, 2016).

In defining genera of Australian Orthotylini , we have focused primarily on endosomal spicule morphology (Cassis, 2008; Cheng et al., 2012a; Cassis and Symonds, 2014a, 2016). As a result we have diagnosed new genera on the number, structure, and arrangement of the endosomal spicules, as well as features of the phallotheca, pygophore, and parameres ( Cassis et al., 2010; Cheng et al., 2012a; Cassis and Symonds, 2014b, 2014a, 2016).

We found that the substructure of PES is critical in defining genera (see also table 5 and fig. 11). Fine details of PES serve as nonhomoplasious synapomorphies in the following Australian genera: (1) Naranjakotta (PES has a curved whiplike apex); (2) Myrtlemiris (PES has a medial membranous region; Cheng et al., 2012a); (3) Acaciacapsus (PES has a downturned medial process; Cassis and Symonds, 2014a); and (4) Blattakeraia (PES has a distally serrate submedial process; this work).

There are also important characters associated with the second dorsal endosomal spicules—